JP2023055740A - Peeling method - Google Patents

Abstract

A device, a semiconductor device, a display device, and a light-emitting device each having a reduced thickness and weight are provided. Alternatively, an element, a semiconductor device, a display device, and a light-emitting device that are difficult to break are provided. Alternatively, a flexible element, semiconductor device, display device, and light-emitting device are provided. A substrate; a first resin layer formed in contact with the substrate; a second resin layer formed in contact with the first resin layer; The second resin layer is composed mainly of polyimide resin, and the interface between the first resin layer and the second resin layer is characterized by LC/MS ( A semiconductor device, a display device, and a light-emitting device using such an element capable of detecting a substance having a mass-to-charge ratio of 300 or more and 950 or less in liquid chromatography (mass spectrometry) measurement are provided. [Selection drawing] Fig. 1

Description

One embodiment of the present invention relates to an element, a semiconductor device, a display device, a separation method, and a method for manufacturing an element display device.

Note that one embodiment of the present invention is not limited to the above technical field. A technical field of one embodiment of the invention disclosed in this specification and the like relates to a product, a method, or a manufacturing method. Alternatively, one aspect of the present invention relates to a process, machine, manufacture, or composition (composition
of Matter). Therefore, the technical fields of one embodiment of the present invention disclosed in this specification more specifically include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, memory devices, driving methods thereof, Alternatively, manufacturing methods thereof can be given as an example.

Semiconductor elements, display elements, and the like are manufactured by laminating and processing various thin films on a glass substrate. Since glass has high heat resistance and high rigidity, it is possible to fabricate various elements on its substrates. Devices fabricated on glass substrates are widely used in displays. It is

On the other hand, a glass substrate having sufficient rigidity requires a certain thickness, and if it is large, its weight also increases, making it difficult to handle. Another aspect of glass is that it is fragile and susceptible to impact, making it easy to break.

Therefore, attention is being paid to semiconductor devices and display devices using resin substrates that are light and hard to break.

However, resins are generally weak against heat and often cannot withstand the heat applied to fabricate high-performance devices. In addition, there is also the problem that high-precision processing is difficult because the material is easily bent, expanded, and contracted.

By the way, a semiconductor device and a display device using a substrate made of resin can be used by having a curved surface or changing the shape by using a flexible substrate. This is a feature that is difficult to realize in a device using a hard and brittle glass substrate.

Such semiconductor devices and display devices are expected to be applied to various uses. For example, Patent Literature 1 discloses a flexible light-emitting device to which an organic EL (Electroluminescence) element is applied.

JP 2014-197522 A

An object of one embodiment of the present invention is to provide a thin and lightweight element, a semiconductor device, a display device, and a light-emitting device. Another object of one embodiment of the present invention is to provide an element, a semiconductor device, a display device, and a light-emitting device that are not easily damaged. Another object of one embodiment of the present invention is to provide a flexible element, a semiconductor device, a display device, and a light-emitting device.

An object of one embodiment of the present invention is to provide an element, a semiconductor device, a display device, and a light-emitting device which are thin, lightweight, and inexpensive. Alternatively, it is an object of one embodiment of the present invention to provide an element, a semiconductor device, a display device, and a light-emitting device that are hard to break and are inexpensive. Another object of one embodiment of the present invention is to provide a flexible and inexpensive element, semiconductor device, display device, and light-emitting device.

An object of one embodiment of the present invention is to provide methods for manufacturing thin and light elements, semiconductor devices, display devices, and light-emitting devices. Another object of one embodiment of the present invention is to provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device that are not easily damaged. An object is to provide methods for manufacturing a semiconductor device, a display device, and a light-emitting device.

An object of one embodiment of the present invention is to provide methods for manufacturing an element, a semiconductor device, a display device, and a light-emitting device which are thin, lightweight, and inexpensive. Alternatively, it is an object of one embodiment of the present invention to provide methods for manufacturing an element, a semiconductor device, a display device, and a light-emitting device that are hard to break and are inexpensive. Alternatively, one aspect of the present invention is a flexible and inexpensive element,
An object is to provide methods for manufacturing a semiconductor device, a display device, and a light-emitting device.

The description of these problems does not preclude the existence of other problems. One aspect of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the descriptions of the specification, drawings, and claims.

One aspect of the present invention includes a substrate, a first resin layer formed in contact with the substrate, a second resin layer formed in contact with the first resin layer, and the second resin layer. The second resin layer is composed mainly of polyimide resin, and the interface between the first resin layer and the second resin layer has an LC /MS (liquid chromatography mass spectrometry) is an element that detects substances with a mass-to-charge ratio of 300 or more and 950 or less.

Another embodiment of the present invention is an element having the above structure, which detects a substance having a mass-to-charge ratio of 350 to 900 in the LC-MS measurement.

Another embodiment of the present invention is an element having the above structure that detects 5 or more, preferably 10 or more substances having a mass-to-charge ratio of 300 to 950 in the LC-MS measurement.

Another embodiment of the present invention is an element in which the substrate has flexibility in the above structure.

Another embodiment of the present invention is a semiconductor device having the above structure, in which a transistor is formed in the first layer.

Another embodiment of the present invention is a semiconductor device having the above structure, in which the transistor includes a metal oxide in a channel formation region.

Another embodiment of the present invention is a display device having the above structure, in which a display element is formed in the one layer.

In another aspect of the present invention, a first resin layer containing polyimide as a main component is formed on a production substrate, a layer to be peeled is formed on the first resin layer, and the first resin layer is formed on the first resin layer. By irradiating the resin layer with laser light, the mass-to-charge ratio in LC/MS measurement inside the first resin layer is:
In the separation method, a separation region containing a substance of 300 to 950 is formed, and the formation substrate and the layer to be separated are separated in the separation region.

In another embodiment of the present invention, a first resin layer containing polyimide as a main component is formed over a formation substrate, a layer to be peeled including a transistor is formed over the first resin layer, and the By irradiating the first resin layer with a laser beam, a separation region containing a substance having a mass-to-charge ratio in LC/MS measurement of 300 or more and 950 or less is formed inside the first resin layer, and the production substrate and the layer to be peeled are separated at the separation region.

Another configuration of the present invention is a peeling method having a separation region containing 5 or more, preferably 10 or more substances having a mass-to-charge ratio of 300 or more and 950 or less in the LC/MS measurement in the above configuration.

In another aspect of the present invention, in the above structure, a separation region containing a substance having a mass-to-charge ratio in LC/MS measurement of 350 or more and 900 or less is formed inside the first resin layer, and The peeling method separates the substrate and the layer to be peeled at the separation region.

Another configuration of the present invention is a peeling method having a separation region containing 5 or more, preferably 10 or more substances having a mass-to-charge ratio of 350 or more and 900 or less in the LC/MS measurement in the above configuration.

Another embodiment of the present invention is a method for manufacturing a semiconductor device having the above structure, in which the transistor includes a metal oxide in a channel formation region.

Another embodiment of the present invention is a method for manufacturing a display device having the above structure, in which the layer to be peeled includes a display element.

Another embodiment of the present invention is a method for manufacturing a light-emitting device having the above structure, in which the layer to be peeled includes a light-emitting element.

Note that the light-emitting device in this specification includes an image display device using a light-emitting element. Moreover, a connector such as an anisotropic conductive film or TCP (Tape Carr) is attached to the light emitting element.
A module with an integrated circuit (IC) mounted on it, a module with a printed wiring board attached to the top of TCP, or a module with an IC (integrated circuit) directly mounted on the light emitting element by the COG (Chip On Glass) method is a light emitting device. may have. Additionally, the luminaire may have a light emitting device.

One embodiment of the present invention can provide a thin and lightweight element, semiconductor device, display device, and light-emitting device. Alternatively, one embodiment of the present invention can provide an element, a semiconductor device, a display device, and a light-emitting device that are not easily damaged. Alternatively, one embodiment of the present invention can provide an integrated element or a semiconductor device. Alternatively, one embodiment of the present invention can provide a flexible element, a semiconductor device, a display device, and a light-emitting device.

One embodiment of the present invention can provide an element, a semiconductor device, a display device, and a light-emitting device that are thin, lightweight, and inexpensive. Alternatively, one embodiment of the present invention can provide an element, a semiconductor device, a display device, and a light-emitting device that are hard to break and are inexpensive. Alternatively, one embodiment of the present invention can provide an integrated and inexpensive element or semiconductor device. Alternatively, one embodiment of the present invention can provide flexible and inexpensive elements, semiconductor devices, display devices, and light-emitting devices.

One embodiment of the present invention can provide methods for manufacturing thin and light elements, semiconductor devices, display devices, and light-emitting devices. Alternatively, one embodiment of the present invention can provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device that are not easily damaged. Alternatively, one embodiment of the present invention can provide a method for manufacturing an integrated element or a semiconductor device. Alternatively, one embodiment of the present invention can provide a method for manufacturing a flexible element, a semiconductor device, a display device, and a light-emitting device.

One embodiment of the present invention can provide methods for manufacturing thin, lightweight, and inexpensive elements, semiconductor devices, display devices, and light-emitting devices. Alternatively, one embodiment of the present invention can provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device that are hard to break and are inexpensive. Alternatively, one embodiment of the present invention can provide a method for manufacturing an integrated and inexpensive element or a semiconductor device. Alternatively, one embodiment of the present invention can provide methods for manufacturing flexible and inexpensive elements, semiconductor devices, display devices, and light-emitting devices.

Alternatively, another embodiment of the present invention can provide a new light-emitting element, a display module, a lighting module, a light-emitting device, a display device, an electronic device, and a lighting device. Alternatively, a light-emitting element with high emission efficiency can be provided. Alternatively, a display module, a lighting module, a light-emitting device, a display device, an electronic device, and a lighting device with low power consumption can be provided.

One embodiment of the present invention should have any one of the above effects.

The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process and an element. 4A and 4B show a peeling process and a light-emitting device or a display device; The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process and an element. 4A and 4B are diagrams showing an element and a light-emitting device or a display device; The figure showing a peeling process. 1A and 1B are diagrams showing a light-emitting device or a display device; A diagram representing an electronic device. A diagram representing an electronic device. A diagram representing an electronic device. Chromatograph on PDA detector obtained by LC/MS analysis of the release layer surface. Absorption spectrum of polyimide film. Chromatographs obtained by LC/MS analysis of comparative samples 1 and 2 with a PDA detector.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and those skilled in the art will easily understand that various changes can be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the descriptions of the embodiments shown below.

Various methods have been proposed for a method of separating elements formed on a fabrication substrate such as a glass substrate from the substrate and bonding them to a different substrate. In general, a method is adopted in which a separation layer made of a resin layer or an inorganic layer is used to form a portion with weak adhesion at the interface or inside thereof, and the elements formed on the production substrate are separated from the production substrate. If the adhesion to the manufacturing substrate is weakened to such an extent that it can be easily separated, peeling will occur during the formation process of the elements. sexuality increases.

Therefore, the present invention provides a separation method capable of separating elements formed on a layer to be separated from a production substrate with high yield. By being able to separate elements with good yield,
It is possible to suppress the increase in cost due to defective products, and to provide products at low prices.

In one embodiment of the present invention, separation is performed using a release layer using a polyimide resin. Since polyimide resin is relatively resistant to heat, it is possible to set a high limiting temperature for heating elements formed in the upper layer. Since sufficient heating can be performed, the reliability of the elements can be improved. In addition, it becomes possible to use an element with a higher fabrication temperature. Specifically 350
Since heating at 10° C. is also possible, it becomes easy to form a semiconductor device using a metal oxide and having good characteristics.

First, a peeling layer made of polyimide resin is formed on a production substrate. A commercially available polyimide resin can be used. Either a polyimide film formed by applying a solution containing a polyimide precursor and imidizing it, or a polyimide film formed by applying polyimide of any kind, or a polyimide film formed by other methods may be used. It doesn't matter if there is.

Subsequently, a layer to be peeled is formed on the peeling layer. The layer to be peeled may be a single layer or a layer consisting of a plurality of layers. For example, transistors, display elements, light-emitting elements, and the like correspond to this. A plurality of types of elements may be included in the layer to be peeled at the same time. In addition, any layer that can be formed over a formation substrate can be formed as a layer to be peeled.

After the layer to be peeled is formed, a supporting substrate is attached to the side of the layer to be peeled opposite to the glass substrate side using a sealing material, an adhesive, or the like. The support substrate may be used as it is after that without being separated, or a temporary substrate may be used on the premise that another separation step is performed.

After the supporting substrate is attached, the separation layer is irradiated with laser light through the formation substrate. The production substrate transmits the laser light and has sufficient heat resistance, rigidity, and strength to form the elements included in the layer to be peeled
It should have a sufficiently small expansion rate. Specifically, a glass substrate or the like is preferable.

Irradiation with laser light causes decomposition of molecules contained in the polyimide film, which is the layer to be peeled, including polyimide molecules. As a result, the strength of the film at the decomposed portion is lowered, and the layer to be peeled can be separated from the support substrate with a sufficiently small force.

Various molecules generated by decomposition of the polyimide film are present at the interface where the separation occurs. At this time, it prevents unintentional peeling, prevents damage to the layer to be peeled, and
It has been found that in a state in which the substrate to be prepared and the layer to be peeled can be separated with an appropriate trigger and force, a decomposed product of a specific molecular weight is present at the interface in a state of good peeling performance.

As described above, one or more substances having a molecular weight of 1000 or less are present at the interface that exhibits good peeling performance. Further, when the substance present at the peeling interface is washed away with an arbitrary organic solvent, and the obtained washing liquid is analyzed by LC/MS (liquid chromatography mass spectrometry), the mass-to-charge ratio (m/z) is 300 or more and 950 or less, preferably is one ion from 350 to 900,
Alternatively, multiple detections are made. The better the releasability, the more substances with a mass-to-charge ratio (m/z) detected from the interface of 300 or more and 950 or less, preferably 350 or more and 900 or less. Substances, more preferably 20 or more substances, more preferably 30 or more substances are detected. The number of substances detected is different if they have the same mass-to-charge ratio or molecular weight but different retention times in the liquid chromatographic separation in the LC/MS analysis. Furthermore, the LC/MS photodiode array (P
DA) In the chromatogram in the detector, the interface having better peelability has a larger amount of substances having a mass-to-charge ratio (m/z) of 300 to 950, preferably 350 to 900, that is, an area intensity ratio. Substances or ions detected from the peeled interface are substances generated as a result of decomposition of polyimide by laser irradiation, and do not include substances or ions derived from the glass substrate or the film used for peeling.

Therefore, by irradiating laser light so as to generate such decomposed products, products requiring a peeling method can be manufactured with a high yield and can be provided at low cost.

When a glass substrate is used and a polyimide film having a thickness of about 1 μm is used as a peeling layer, for example,
A XeCl excimer laser with a wavelength of 308 nm was used as the laser oscillator of the laser light, the setting energy of the oscillator was 980 mJ, the repetition frequency was 60 Hz, and the scan speed was 11.7.
mm/sec, and by adjusting the optical system, the cross section of the laser beam is formed into a linear shape of 0.6 mm × 300 mm, and an attenuator is used in the optical system, and the attenuation rate of the irradiation energy by the attenuator is 10%. Of course, other lasers may be used.

Note that a transistor is preferably formed in the layer to be peeled. A metal oxide is preferably included in a channel formation region of the transistor. A metal oxide can function as an oxide semiconductor.

Low temperature polysilicon (LTPS) is used in the channel formation region of the transistor.
In the case of using nature Poly-Silicon), it is necessary to apply a temperature of about 500° C. to 550° C., so the release layer is required to have high heat resistance.

However, a transistor using a metal oxide for a channel formation region can be formed at 350° C. or lower, further 300° C. or lower. Therefore, the layer to be peeled is not required to have high heat resistance. Therefore, the heat resistance temperature of the layer to be peeled can be lowered, and the range of selection of materials is widened.
Moreover, compared with the case of using LTPS, the process can be simplified, which is preferable.

In this embodiment, since the isolation region is formed inside the peeling layer, the thickness of the peeling layer is 15 nm.
It is preferable that the thickness is 50 μm or more and 50 μm or less. Note that the thickness of the release layer is 50 nm or more and 20 μm.
The following are preferable. By thinning the release layer as much as possible within the film thickness range,
It is possible to achieve weight reduction, thin film reduction, cost reduction, and flexibility improvement.

The element, the semiconductor device, the light-emitting device, and the display device of this embodiment are specifically described below together with their manufacturing methods.

The thin films (insulating films, semiconductor films, conductive films, etc.) that make up these elements and devices can be formed by sputtering, chemical vapor deposition (CVD).
) method, vacuum deposition method, pulse laser deposition (PLD: Pulse Laser Depos
ion) method, atomic layer deposition (ALD: Atomic Layer Deposition)
n) can be formed using a method or the like. As a CVD method, plasma chemical vapor deposition (P
ECVD) method or thermal CVD method may be used. As an example of the thermal CVD method, metal-organic chemical vapor deposition (
A MOCVD (Metal Organic CVD) method may also be used.

Thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device are processed by spin coating, dipping,
It can be formed by spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, knife coating, and the like.

When processing the thin film, it can be processed using a lithography method or the like. Alternatively, an island-shaped thin film may be formed by a film formation method using a shielding mask. Alternatively, the thin film may be processed by a nanoimprint method, a sandblast method, a lift-off method, or the like. Photolithography includes a method of forming a resist mask on a thin film to be processed, processing the thin film by etching or the like, and removing the resist mask, and a method of forming a photosensitive thin film, followed by exposure and development. and a method of processing the thin film into a desired shape.

When light is used in the lithography method, the light used for exposure is, for example, i-line (wavelength: 365 nm).
m), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof can be used. In addition, ultraviolet light, KrF laser light, ArF laser light, or the like can also be used. Moreover, you may expose by a liquid immersion exposure technique. As the light used for exposure, extreme ultraviolet light (EUV: Extreme Ultra-violet) or X-rays may be used. An electron beam can also be used instead of the light used for exposure. The use of extreme ultraviolet light, X-rays, or electron beams is preferable because extremely fine processing is possible. A photomask is not necessary when exposure is performed by scanning a beam such as an electron beam.

A dry etching method, a wet etching method, a sandblasting method, or the like can be used for etching the thin film.

[Manufacturing method example 1]
A peeling method of one embodiment of the present invention is described below using a display device as an example. First, production substrate 1
4, a release layer 23 is formed (FIG. 1).

FIG. 1A shows an example in which a resin layer 24 is formed over the entire surface of the production substrate 14 by using a coating method. The method for forming the resin layer 24 is not limited to this, and a printing method or the like may be used.

The resin layer 24 can be formed using various resin materials (including resin precursors). The resin layer 24 is preferably formed using a thermosetting material. In this embodiment,
The resin layer 24 is formed using a material having no photosensitivity (also referred to as a non-photosensitive material).

The resin layer 24 is preferably formed using a material containing a polyimide resin or a polyimide resin precursor. The resin layer 24 can be formed using, for example, a material containing polyimide resin and a solvent, or a material containing polyamic acid and a solvent.

The resin layer 24 is preferably formed using a spin coater. A thin film can be uniformly formed on a large-sized substrate by using the spin coating method.

The release layer 23 is preferably formed using a solution having a viscosity of 5 cP or more and less than 500 cP, preferably 5 cP or more and less than 100 cP, more preferably 10 cP or more and 50 cP or less. The lower the viscosity of the solution, the easier it is to apply. In addition, the lower the viscosity of the solution, the more it is possible to suppress the inclusion of air bubbles and form a good quality film.

Other methods for forming the resin layer 24 include dipping, spray coating, inkjet,
Dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, knife coating and the like can be mentioned.

The fabrication substrate 14 has rigidity to facilitate transportation, heat resistance to withstand the temperatures involved in the fabrication process of elements to be formed later, and transparency to the laser beam irradiated in the peeling process. A material with lightness is used. Materials that can be used for the production substrate 14 include, for example,
Examples include glass, quartz, sapphire, and resin. Among these, glass is preferable because of its versatility and from the viewpoint of cost and large area. Examples of glass include alkali-free glass, barium borosilicate glass, and aluminoborosilicate glass.

Next, the release layer 23 is formed by performing a first heat treatment on the resin layer 24 (see FIG. 1 (
B)).

The first heat treatment can reduce degassing components (eg, hydrogen, water, etc.) in the peeling layer 23 . In particular, it is preferable to heat at a temperature equal to or higher than the manufacturing temperature of each layer formed on the release layer 23 . As a result, degassing from the peeling layer 23 can be greatly suppressed in the manufacturing process of the transistor.

For example, when the transistor manufacturing temperature is up to 350° C., the film to be the peeling layer 23 is 35° C.
It is preferable to heat at 0 ° C. or higher and 450 ° C. or lower, more preferably 400 ° C. or lower, and 375
It is more preferable to heat at ℃ or less. As a result, degassing from the peeling layer 23 can be greatly suppressed in the manufacturing process of the transistor.

It is preferable to set the maximum temperature for manufacturing the transistor equal to the temperature for the first heat treatment because the first heat treatment can prevent the maximum temperature for manufacturing the display device from increasing.

By lengthening the treatment time, even when the heating temperature is relatively low, it may be possible to achieve the same peelability as when the heating temperature is higher. Therefore, if the heating temperature cannot be increased due to the configuration of the heating device, it is preferable to lengthen the processing time.

The time for the first heat treatment is, for example, preferably 5 minutes or more and 24 hours or less, more preferably 30 minutes or more and 12 hours or less, and even more preferably 1 hour or more and 6 hours or less. Note that the time for the first heat treatment is not limited to this. For example, the first heat treatment is RTA (Rapid The
In the case of using the rmal annealing method, the time may be less than 5 minutes.

As the heating device, various devices can be used, such as an electric furnace and a device that heats the object by heat conduction or heat radiation from a heating element such as a resistance heating element. For example, GRTA (G
as Rapid Thermal Anneal) device, LRTA (Lamp Rap
An RTA device such as an id Thermal Anneal) device can be used. LR
A TA apparatus is an apparatus that heats an object to be processed by radiation of light (electromagnetic waves) emitted from lamps such as halogen lamps, metal halide lamps, xenon arc lamps, carbon arc lamps, high pressure sodium lamps, and high pressure mercury lamps. The GRTA apparatus is an apparatus that performs heat treatment using high-temperature gas. The use of the RTA apparatus can shorten the processing time, which is preferable for mass production. Alternatively, the heat treatment may be performed using an in-line heating apparatus.

Note that the thickness of the release layer 23 may change from the thickness of the resin layer 24 due to heat treatment. For example, the release layer 23 may become thinner than the resin layer 24 due to the removal of the solvent contained in the resin layer 24 or the increase in density due to progress of curing. Alternatively, the release layer 23 may become thicker than the resin layer 24 due to an increase in volume due to the inclusion of heating atmosphere components during the heat treatment.

Heat treatment (also referred to as pre-baking treatment) for removing the solvent contained in the resin layer 24 may be performed before performing the first heat treatment. The temperature of the prebaking treatment can be appropriately determined according to the material used. For example, it can be performed at 50° C. or higher and 180° C. or lower, 80° C. or higher and 150° C. or lower, or 90° C. or higher and 120° C. or lower. Alternatively, the first heat treatment may serve as a pre-bake treatment, and the solvent contained in the resin layer 24 may be removed by the first heat treatment.

The release layer 23 has flexibility. The fabrication substrate 14 has lower flexibility than the peeling layer 23 .

The thermal expansion coefficient of the release layer 23 is preferably 0.1 ppm/° C. or more and 50 ppm/° C. or less, more preferably 0.1 ppm/° C. or more and 20 ppm/° C. or less, and 0.1 pp
More preferably, it is m/°C or more and 10 ppm/°C or less. The lower the coefficient of thermal expansion of the peeling layer 23, the more it is possible to suppress the occurrence of cracks in the layers constituting the transistors and the like due to heating.

Note that when the peeling layer 23 is finally positioned on the display surface side of the display device, light from the display element is transmitted through the peeling layer 23 and observed. It preferably has high translucency to visible light.

Next, the layer to be peeled 21 is formed on the peeling layer 23 . In this embodiment, an example in which a transistor and a display element are formed as elements to be formed in the layer to be separated 21 is shown; Arbitrary elements may be formed.

As the layer to be peeled 21, first, an insulating layer 31 is formed on the peeling layer 23 (FIG. 1C).

The insulating layer 31 is formed at a temperature equal to or lower than the heat-resistant temperature of the peeling layer 23 . It is preferably formed at a temperature lower than the temperature of the first heat treatment.

The insulating layer 31 can be used as a barrier layer that prevents impurities contained in the separation layer 23 from diffusing into a transistor or a display element in a layer to be separated later. For example, insulating layer 3
1 preferably has a function of preventing moisture or the like contained in the peeling layer 23 from diffusing into the transistor or the display element when the peeling layer 23 is heated. Therefore, the insulating layer 31 preferably has a high barrier property.

As the insulating layer 31, for example, a silicon nitride film, a silicon oxynitride film, a silicon oxide film,
An inorganic insulating film such as a silicon nitride oxide film, an aluminum oxide film, or an aluminum nitride film can be used. In addition, hafnium oxide film, yttrium oxide film, zirconium oxide film,
A gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, a neodymium oxide film, or the like may be used. Further, two or more of the insulating films described above may be laminated and used. In particular, it is preferable to form a silicon nitride film over the separation layer 23 and form a silicon oxide film over the silicon nitride film.

Note that in this specification and the like, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen. point to the material.

The inorganic insulating film is preferably formed at a high temperature because the higher the film formation temperature, the denser the inorganic insulating film and the higher the barrier property.

The substrate temperature at the time of forming the insulating layer 31 is preferably room temperature (25° C.) or more and 350° C. or less.
°C or higher and 300 °C or lower is more preferable.

Next, a transistor 40 is formed over the insulating layer 31 (FIG. 1C).

There is no particular limitation on the structure of the transistor included in the display device. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Further, the transistor structure may be either a top-gate structure or a bottom-gate structure. Alternatively, gate electrodes may be provided above and below the channel.

Here, the case of manufacturing a bottom-gate transistor including a metal oxide layer 44 as the transistor 40 is shown. Metal oxide layer 44 can function as a semiconductor layer of transistor 40 . A metal oxide can function as an oxide semiconductor.

In this embodiment, an oxide semiconductor is used as a semiconductor of the transistor. A semiconductor material with a wider bandgap and a lower carrier density than silicon is preferably used because the current in the off state of the transistor can be reduced.

The transistor 40 is formed at a temperature equal to or lower than the heat-resistant temperature of the peeling layer 23 . The transistor 40 is preferably formed at a temperature lower than the temperature of the first heat treatment.

Specifically, first, the conductive layer 41 is formed on the insulating layer 31 . The conductive layer 41 can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask.

The substrate temperature during the formation of the conductive film is preferably room temperature or higher and 350° C. or lower, and more preferably room temperature or higher and 300° C. or lower.

Each of the conductive layers included in the display device has a single-layer structure or a metal such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or an alloy containing these as a main component. It can be used as a laminated structure. Alternatively, indium oxide, indium tin oxide (ITO), indium oxide containing tungsten, indium zinc oxide containing tungsten, indium oxide containing titanium, ITO containing titanium, indium zinc oxide, zinc oxide (ZnO) , ZnO containing gallium, or ITO containing silicon may be used. Alternatively, a semiconductor such as polycrystalline silicon or an oxide semiconductor, or a silicide such as nickel silicide, whose resistance is reduced by containing an impurity element or the like, may be used. A film containing graphene can also be used. A film containing graphene can be formed, for example, by reducing a film containing graphene oxide. Alternatively, a semiconductor such as an oxide semiconductor containing an impurity element may be used. Alternatively, it may be formed using a conductive paste such as silver, carbon, or copper, or a conductive polymer such as polythiophene. Conductive paste is inexpensive and preferred. Conductive polymers are preferred because they are easy to apply.

Subsequently, an insulating layer 32 is formed. The insulating layer 32 can use an inorganic insulating film that can be used for the insulating layer 31 .

Subsequently, a metal oxide layer 44 is formed. The metal oxide layer 44 can be formed by forming a metal oxide film, forming a resist mask, etching the metal oxide film, and then removing the resist mask.

The substrate temperature during formation of the metal oxide film is preferably 350° C. or lower, more preferably room temperature or higher and 200° C. or lower, and even more preferably room temperature or higher and 130° C. or lower.

A metal oxide film can be formed using either one or both of an inert gas and an oxygen gas. Note that there is no particular limitation on the oxygen flow rate (oxygen partial pressure) during the formation of the metal oxide film. However, in order to obtain a transistor with high field-effect mobility, the oxygen flow ratio (oxygen partial pressure) during the formation of the metal oxide film is preferably 0% or more and 30% or less.
% or more and 30% or less, more preferably 7% or more and 15% or less.

The metal oxide film preferably contains at least indium or zinc. In particular, it preferably contains indium and zinc.

The metal oxide preferably has an energy gap of 2.0 eV or more, and 2.5 eV
more preferably. It is more preferably 3.0 eV or more. By using a metal oxide with a wide energy gap in this manner, off-state current of a transistor can be reduced.

A metal oxide film can be formed by a sputtering method. In addition, the PLD method,
A PECVD method, a thermal CVD method, an ALD method, a vacuum deposition method, or the like may be used.

Subsequently, a conductive layer 43a and a conductive layer 43b are formed. The conductive layer 43a and the conductive layer 43b are
It can be formed by forming a resist mask after forming a conductive film, etching the conductive film, and then removing the resist mask. The conductive layers 43a and 43b are connected to the metal oxide layer 44 respectively.

Note that a part of the metal oxide layer 44 that is not covered with the resist mask may be thinned by etching during the processing of the conductive layers 43a and 43b.

The substrate temperature during the formation of the conductive film is preferably room temperature or higher and 350° C. or lower, and more preferably room temperature or higher and 300° C. or lower.

As described above, the transistor 40 can be manufactured (FIG. 1C). In the transistor 40, part of the conductive layer 41 functions as a gate, part of the insulating layer 32 functions as a gate insulating layer, and the conductive layers 43a and 43b each function as either a source or a drain. .

Next, an insulating layer 33 is formed to cover the transistor 40 (FIG. 1D). The insulating layer 33 can be formed by a method similar to that of the insulating layer 31 .

Further, as the insulating layer 33, an oxide insulating film such as a silicon oxide film or a silicon oxynitride film formed in an atmosphere containing oxygen is preferably used. Furthermore, it is preferable to stack an insulating film such as a silicon nitride film, in which oxygen hardly diffuses or permeates, over the silicon oxide film or the silicon oxynitride film. An oxide insulating film formed in an atmosphere containing oxygen can easily release a large amount of oxygen by heating. Oxygen can be supplied to the metal oxide layer 44 by performing heat treatment in a state where such an oxide insulating film that releases oxygen and an insulating film that hardly diffuses and permeates oxygen are stacked. As a result, oxygen vacancies in the metal oxide layer 44 and defects at the interface between the metal oxide layer 44 and the insulating layer 33 can be repaired, and the defect level can be reduced.
Accordingly, a highly reliable display device can be realized.

Through the above steps, the insulating layer 31, the transistor 40, and the insulating layer 33 can be formed over the separation layer 23 (FIG. 1D).

When an organic insulating film is used for the insulating layer 34, the temperature applied to the separation layer 23 during formation of the insulating layer 34 is preferably room temperature or higher and 350° C. or lower, and more preferably room temperature or higher and 300° C. or lower.

When an inorganic insulating film is used for the insulating layer 34, the substrate temperature during film formation is preferably room temperature or higher and 350° C. or lower, and more preferably 100° C. or higher and 300° C. or lower.

Next, an opening is formed in the insulating layer 34 and the insulating layer 33 to reach the conductive layer 43b.

After that, a conductive layer 61 is formed (FIG. 1E). Part of the conductive layer 61 is the light emitting element 60
function as a pixel electrode. The conductive layer 61 can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask.

The conductive layer 61 is formed at a temperature equal to or lower than the heat-resistant temperature of the peeling layer 23 . The conductive layer 61 is preferably formed at a temperature lower than the temperature of the first heat treatment.

The substrate temperature during the formation of the conductive film is preferably room temperature or higher and 350° C. or lower, and more preferably room temperature or higher and 300° C. or lower.

Next, an insulating layer 35 is formed to cover the end of the conductive layer 61 (FIG. 1E). The insulating layer 35 can use an organic insulating film or an inorganic insulating film that can be used for the insulating layer 31 .

The insulating layer 35 is formed at a temperature equal to or lower than the heat-resistant temperature of the peeling layer 23 . The insulating layer 35 is preferably formed at a temperature lower than the temperature of the first heat treatment.

When an organic insulating film is used for the insulating layer 35, the temperature applied to the separation layer when forming the insulating layer 35 is preferably room temperature or higher and 350° C. or lower, and more preferably room temperature or higher and 300° C. or lower.

When an inorganic insulating film is used for the insulating layer 35, the substrate temperature during film formation is preferably room temperature or higher and 350° C. or lower, and more preferably 100° C. or higher and 300° C. or lower.

Next, an EL layer 62 and a conductive layer 63 are formed (FIG. 2A). Part of the conductive layer 63 functions as a common electrode for the light emitting elements 60 .

The EL layer 62 can be formed by a vapor deposition method, a coating method, a printing method, an ejection method, or the like. E.
When the L layer 62 is separately formed for each pixel, it can be formed by a vapor deposition method using a shadow mask such as a metal mask, an inkjet method, or the like.

The EL layer 62 may use either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound.

The conductive layer 63 can be formed using a vapor deposition method, a sputtering method, or the like.

The conductive layer 63 is formed at a temperature equal to or lower than the heat-resistant temperature of the peeling layer 23 and at a temperature equal to or lower than the heat-resistant temperature of the EL layer 62 . Further, it is preferable to form the film at a temperature lower than the temperature of the first heat treatment.

As described above, the light emitting element 60 can be formed (FIG. 2A). light emitting element 60
has a structure in which a conductive layer 61 partly functioning as a pixel electrode, an EL layer 62, and a conductive layer 63 partly functioning as a common electrode are stacked.

The light emitting element may be of top emission type, bottom emission type, or dual emission type. A conductive film that transmits visible light is used for the electrode on the light extraction side.
A conductive film that reflects visible light is preferably used for the electrode on the side from which light is not extracted. Here, it is assumed that a top-emission light-emitting element is manufactured.

Next, an insulating layer 74 is formed to cover the conductive layer 63 (FIG. 2B). The insulating layer 74 functions as a protective layer that prevents impurities such as water from diffusing into the light emitting element 60 . light emitting element 60
are encapsulated by an insulating layer 74 . After forming the conductive layer 63, the insulating layer 74 is preferably formed without exposure to the air.

The insulating layer 74 is formed at a temperature lower than the heat resistant temperature of the peeling layer 23 and lower than the heat resistant temperature of the light emitting element 60 . The insulating layer 74 is preferably formed at a temperature lower than the temperature of the first heat treatment.

The insulating layer 74 preferably has a structure including, for example, an inorganic insulating film with a high barrier property that can be used for the insulating layer 31 described above. Alternatively, an inorganic insulating film and an organic insulating film may be laminated and used.

The insulating layer 74 can be formed using an ALD method, a sputtering method, or the like. The ALD method and the sputtering method are preferable because low-temperature film formation is possible. The use of the ALD method is preferable because the coverage of the insulating layer 74 is good.

Next, a protective layer 75 is formed over the insulating layer 74 (FIG. 2C). The protective layer 75 can be used as the topmost layer of the display device. The protective layer 75 preferably has high transparency to visible light.

It is preferable to use an organic insulating film that can be used for the insulating layer 31 as the protective layer 75 because the surface of the display device can be prevented from being damaged or cracked.

In FIG. 3A, instead of the protective layer 75, a substrate 75 is formed on an insulating layer 74 using an adhesive layer 75b.
An example in which a is pasted together is shown.

For the adhesive layer 75b, various resins of various curable adhesives such as photocurable adhesives such as ultraviolet curable adhesives, reaction curable adhesives, thermosetting adhesives, and anaerobic adhesives can be used. Alternatively, an adhesive sheet or the like may be used.

For the substrate 75a, for example, polyester resin such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES ) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) Resin, ABS resin, cellulose nanofiber, etc. can be used. Various materials such as glass, quartz, resin, metal, alloy, and semiconductor may be used for the substrate 75a. In addition, when peeling off again and sticking to a different substrate, the substrate 7
Any substrate may be used for 5a. Also, in order to have flexibility, the substrate 75a
Depending on the thickness and material of the substrate, a substrate having a material and shape having a required degree of flexibility may be used.

Next, the production substrate 14 and the separation layer 23 are separated. For separation, the separation layer 23 is irradiated with laser light from the production substrate 14 side through the production substrate 14 to form a separation region 25 inside the separation layer 23 .
is formed (FIG. 3(B)). The separation region 25 is separated from the separation layer 2 by irradiating laser light.
This is the part where the molecules that make up 3 are decomposed and become brittle. Note that the separation region 25 in the figure is the separation layer 2
3 , it may be formed at the interface with the production substrate 14 in the separation layer 23 . When the separation layer 23 is made of polyimide resin, the separation region 25 includes LC/
At least one substance derived from ions having a mass-to-charge ratio of 300 to 950, preferably 350 to 900 in MS measurement is included. Such molecules are products of decomposition of polyimide due to laser irradiation, and can easily be produced on substrate 1 with an appropriate amount of force.
4 can be observed in the separation region 25 with good release performance. In the final product, since the molecule remains on the surface separated as the separation region 25, its presence can be confirmed by measurement.

For example, the laser to be irradiated is
A XeCl excimer laser with a wavelength of 308 nm was used as the laser oscillator of the laser light, the setting energy of the oscillator was 980 mJ, the repetition frequency was 60 Hz, and the scan speed was 11.7.
mm/sec, and by adjusting the optical system, the cross section of the laser beam is formed into a linear shape of 0.6 mm × 300 mm, and an attenuator is used in the optical system, and the attenuation rate of the irradiation energy by the attenuator is 10%. Of course, other lasers may be used.

After that, for example, by applying a pulling force to the separation region 25 in the vertical direction, the production substrate 1
The layer to be peeled can be peeled off from 4 (FIG. 3(C)). Specifically, the layer to be separated can be easily peeled off from the production substrate 14 by sucking a part of the upper surface of the substrate 75a and pulling it upward.

Here, at the time of peeling, a liquid containing water such as water or an aqueous solution is added to the peeling interface, and the peeling is performed so that the liquid permeates the peeling interface, whereby the peelability can be improved. In addition, it is possible to prevent static electricity generated at the time of peeling from adversely affecting functional elements such as transistors (destruction of semiconductor elements due to static electricity, etc.).

A starting point of separation may be formed by separating part of the separation layer 23 from the formation substrate 14 before the separation. For example, the starting point of separation may be formed by inserting a sharp instrument such as a knife into the separation region 25 . Alternatively, the release layer 23 may be cut with a sharp instrument from the substrate 75a side to form a separation starting point. Alternatively, a separation starting point may be formed by a method using a laser such as a laser ablation method.

The separation region 25 exposed by separation from the production substrate 14 and the substrate 29 may be bonded together using an adhesive layer 28 (FIG. 3D). The substrate 29 can function as a support substrate of the display device.

A material that can be used for the adhesive layer 75 b can be applied to the adhesive layer 28 . A material that can be used for the substrate 75 a can be applied to the substrate 29 .

Through the above steps, a display device in which a metal oxide is applied to a channel formation region of a transistor and an EL element is applied can be manufactured.

At least a substance derived from ions having a mass-to-charge ratio of 300 to 950, preferably 350 to 900, is present at the interface between the adhesive layer 28 and the peeling layer 23 of the display device thus manufactured. 1 will be included. In LC/MS measurement, substances derived from ions with a mass-to-charge ratio of 300 to 950 were generated by decomposition due to laser irradiation, and the other portion, that is, the interface between the peeling layer 23 and the layer to be peeled ( It is not detected at the interface with the insulating layer 31).

[Production method example 2]
In the following manufacturing method examples, the description of the same parts as in the manufacturing method example described above may be omitted.

First, the insulating layer 33 to the protective layer 75 are formed in the same manner as in the manufacturing method example 1. Next, as shown in FIG. It should be noted that when these constituent elements are manufactured, they are formed at a temperature equal to or lower than the heat resistance temperature of the peeling layer 23 . Each of these components is preferably formed at a temperature lower than both the temperature of the first heat treatment and the temperature of the second heat treatment.

Then, a separation region 25 is formed inside the separation layer 23 in at least a portion of the production substrate 14 where an element to be separated is formed by irradiating laser light. (FIG. 4(A)) The type, wavelength, output, etc. of the laser comply with the manufacturing method 1. FIG. At this time, the peeling layer 23 is provided with a portion that is not irradiated with laser light. Since the separation region 25 is not formed in the portion that is not irradiated with the laser beam, it is possible to prevent accidental peeling during transportation or the like.

Next, starting points of separation are formed in the release layer 23 (FIGS. 4B1 and 4B2).

For example, from the protective layer 75 side, a sharp-edged instrument 65 such as a knife is inserted into the inside of the end of the separation region 25 to make a frame-like cut 64 . This break 64 is the starting point of separation.

Alternatively, the inside of the separation region 25 in the peeling layer 23 may be irradiated with a frame-shaped laser beam and used as the starting point of the separation.

Note that in the case of forming a plurality of display devices with one manufacturing substrate (manufacturing multiple substrates), FIG.
, it is preferable to arrange a plurality of display devices inside the break 64 like the separation area 25 . Accordingly, a plurality of display devices can be separated from the manufacturing substrate at once.

Alternatively, a plurality of isolation regions 25 are formed on one fabrication substrate, and isolation regions 2 for each display device are formed.
A display element and a semiconductor element may be separately formed at the positions corresponding to 5. FIG. FIG. 4B3 shows an example in which four isolation regions are formed over the formation substrate. Frame-like cuts 6 in each of the four separation areas
By inserting 4, each display device can be peeled off at different timings.

In manufacturing method example 2, on the manufacturing substrate 14, a portion where the isolation region 25 is formed and a portion where the isolation region 25 is formed.
and a portion where is not formed. Since the separation layer 23 is not brittle in the portion where the separation region 25 is not formed, it is difficult to separate from the production substrate 14 . Therefore, the layer to be peeled 21 can be prevented from being peeled off from the formation substrate 14 at an unintended timing.
By forming the starting point of separation, the production substrate 14 and the layer 2 to be peeled can be separated at desired timing.
1 can be separated. Therefore, the timing of peeling can be controlled, and high peelability can be achieved. Accordingly, the yield of the separation process and the manufacturing process of the display device can be increased.

Next, the formation substrate 14 and the transistor 40 are separated (FIG. 5A).

In manufacturing method example 2, by irradiating the separation layer 23 with laser light, the molecules of the resin contained in the separation layer 23 are decomposed to form the separation regions 25 that are fragile regions.
By further separation, the layer 21 to be separated can be separated from the formation substrate 14 .

Next, the separation region 25 in the release layer 23 exposed by separation from the production substrate 14 and the substrate 29 are bonded together using an adhesive layer 28 (FIG. 5B). The substrate 29 can function as a support substrate of the display device.

Through the above steps, a display device in which a metal oxide is applied to a channel formation region of a transistor and an EL element is applied can be manufactured.

[Configuration example 1 of display device]
FIG. 6A is a top view of the display device 10A. 6B and 6C are examples of a cross-sectional view of the display unit 381 of the display device 10A and a cross-sectional view of the connecting portion with the FPC 372, respectively.

The display device 10A can be manufactured using the manufacturing method example 2 described above. Display device 10A
can be held in a bent state or repeatedly bent.

The display device 10A has a protective layer 75 and a substrate 29. As shown in FIG. The protective layer 75 side is the display surface side of the display device. The display device 10A has a display section 381 and a drive circuit section 382 . Display device 1
An FPC 372 is attached to 0A.

The conductive layer 43c and the FPC 372 are electrically connected via the connector 76 (see FIG. 6 (
B), (C)). The conductive layer 43c can be formed using the same material and in the same process as the source and drain of the transistor.

Various anisotropic conductive films (ACF: Anisotropic C
inductive Film) and anisotropic conductive paste (ACP: Anisotrop
IC Conductive Paste) or the like can be used.

The display device shown in FIG. 6C differs from the structure in FIG. 6B in that a transistor 49 is included instead of the transistor 40 and a colored layer 97 is provided over the insulating layer 33. . When using the bottom emission type light emitting device 60 , a colored layer 97 may be provided between the light emitting device 60 and the substrate 29 .

A transistor 49 illustrated in FIG. 6C has a conductive layer 45 functioning as a gate electrode in addition to the structure of the transistor 40 illustrated in FIG. 6B.

A structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates is applied to the transistor 49 . With such a structure, the threshold voltage of the transistor can be controlled. A transistor may be driven by connecting two gates and applying the same signal to them. Such a transistor can increase field-effect mobility and increase on-current compared to other transistors. As a result, a circuit that can be driven at high speed can be manufactured. Furthermore, it is possible to reduce the area occupied by the circuit section. By using a transistor with a large on-current, it is possible to reduce the signal delay in each wiring even when the number of wirings increases when the display device becomes larger or has higher definition, thus suppressing display unevenness. can do.

Alternatively, the threshold voltage of the transistor can be controlled by applying a potential for controlling the threshold voltage to one of the two gates and applying a potential for driving to the other.

As described above, when these display devices are manufactured, the release layer 23 is irradiated with laser light to decompose the resin molecules contained in the release layer 23, and the separation region 25, which is a brittle region, is formed.
is formed, and the layer 21 to be separated can be separated from the formation substrate 14 by separating from the separation region. In the region between the layer 28 and the peeling layer 23 (the interface between the adhesive layer 28 and the peeling layer 23), a mass At least one of substances derived from ions having a charge ratio of 300 or more and 950 or less is present. The peeling layer 23 in which molecules of these molecular weights are present has good peeling performance while suppressing unintentional peeling of the layer 21 to be peeled due to moderate decomposition of the molecules. , the display device can be manufactured with high yield.

Fourier Transform Infrared Spectroscopy
spectroscopy, FTIR), nuclear magnetic resonance spectroscopy ( ¹ H-NMR), gas chromatography mass spectrometry (GC/MS), liquid chromatography mass spectrometry (LC/MS), time-of-flight secondary ion mass spectrometry ( surface of the detached release layer 23 (separation region 25) or adhesion layer 28 using one or more analytical techniques such as TOF-SIMS) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS). By analyzing the surface of , the molecules present at the interface between the release layer 23 and the adhesive layer 28 can be identified.

For analysis by LC/MS, the surface of the peeling interface side of the glass substrate after peeling and the surface of the layer to be peeled on the peeling interface side are subjected to any solvent (toluene, chloroform, 1, 1, 3, 3 - Wash with hexafluoro-2-propanol (abbreviation: HFIP), etc.), and dilute the obtained washing solution with an arbitrary solvent (preferably an organic solvent used for LC/MS measurement, such as acetonitrile) to prepare a measurement sample. .

When analyzing a display device, first, in the transistor structure of the display device, a layer that becomes a separation interface, for example, a layer in which polyimide and an adhesive (epoxy resin or the like) are in contact is specified.
TEM-EDX (transmission electron microscope--energy dispersive X-ray analysis, etc.) can be used as an analytical technique used to identify the peeled interface. A method of analyzing the vicinity of the specified interface by an analysis method that can obtain molecular weight distribution information in the depth direction such as TOF-SIMS (time-of-flight secondary ion mass spectrometry),
Analysis can be performed using an analytical technique capable of obtaining lateral molecular weight distribution information, such as ALDI-MS (matrix-assisted laser desorption/ionization mass spectrometry). In addition, after specifying the peeling interface by the above method, peeling at the peeling interface and exposing the surface, the surfaces of both peeling interfaces are washed with an arbitrary solvent (toluene, chloroform, HFIP, etc.) to obtain The washed solution is diluted with an arbitrary solvent (preferably an organic solvent used for LC/MS measurement such as acetonitrile) to prepare a measurement sample, which can be subjected to LC/MS analysis.

[Production method example 3]
First, in the same manner as in Manufacturing Method Example 2, the separation layer 23 to the insulating layer 31 are formed over the manufacturing substrate 14 (FIG. 7A).

Next, a transistor 80 is formed over the insulating layer 31 (FIG. 7B).

Here, the case where a transistor having a metal oxide layer 83 and two gates is manufactured as the transistor 80 is shown.

The transistor 80 is formed at a temperature equal to or lower than the heat-resistant temperature of the peeling layer 23 . It is preferably formed at a temperature lower than both the temperature of the first heat treatment and the temperature of the second heat treatment.

Specifically, first, the conductive layer 81 is formed on the insulating layer 31 . The conductive layer 81 can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask.

Subsequently, an insulating layer 82 is formed. The insulating layer 82 can use an inorganic insulating film that can be used for the insulating layer 31 .

Subsequently, a metal oxide layer 83 is formed. The metal oxide layer 83 can be formed by forming a metal oxide film, forming a resist mask, etching the metal oxide film, and then removing the resist mask. A material that can be used for the metal oxide layer 44 can be used for the metal oxide layer 83 .

Subsequently, an insulating layer 84 and a conductive layer 85 are formed. The insulating layer 84 can use an inorganic insulating film that can be used for the insulating layer 31 . The insulating layer 84 and the conductive layer 85 are formed by forming an insulating film to be the insulating layer 84 and a conductive film to be the conductive layer 85, forming a resist mask, etching the insulating film and the conductive film, and forming a resist. It can be formed by removing the mask.

Next, the insulating layer 33 covering the metal oxide layer 83, the insulating layer 84, and the conductive layer 85 is formed. The insulating layer 33 can be formed by a method similar to that of the insulating layer 31 .

The insulating layer 33 preferably contains hydrogen. Hydrogen contained in the insulating layer 33 diffuses into the metal oxide layer 83 in contact with the insulating layer 33, and the resistance of a part of the metal oxide layer 83 is lowered. insulating layer 33
Since the metal oxide layer 83 in contact with functions as a low-resistance region, it is possible to increase the on current of the transistor 80 and improve the field effect mobility.

Next, an opening is formed in the insulating layer 33 to reach the metal oxide layer 83 .

Subsequently, a conductive layer 86a and a conductive layer 86b are formed. The conductive layer 86a and the conductive layer 86b are
It can be formed by forming a resist mask after forming a conductive film, etching the conductive film, and then removing the resist mask. The conductive layers 86a and 86b are electrically connected to the metal oxide layer 83 through openings in the insulating layer 33, respectively.

As described above, the transistor 80 can be manufactured (FIG. 7B). In transistor 80, part of conductive layer 81 functions as a gate, part of insulating layer 84 functions as a gate insulating layer, part of insulating layer 82 functions as a gate insulating layer, and part of conductive layer 85 functions as a gate insulating layer. acts as a gate. Metal oxide layer 83 has a channel region and a low resistance region. The channel region overlaps the conductive layer 85 with the insulating layer 84 interposed therebetween. The low resistance region has a portion connected to the conductive layer 86a and a portion connected to the conductive layer 86b.

Next, the insulating layer 34 to the light emitting element 60 are formed on the insulating layer 33 (FIG. 7C). Manufacturing method example 1 can be referred to for these steps.

The steps of FIGS. 8A and 8B are performed independently of the steps of FIGS. 7A to 7C.
A separation layer 93 is formed on a production substrate 91 in the same manner as the step of forming the separation layer 23 on the production substrate 14 .
to form

Next, an insulating layer 95 is formed on the separation layer 93 . Next, a colored layer 97 and a light shielding layer 98 are formed over the insulating layer 95 (FIG. 8B).

As for the insulating layer 95, the description of the insulating layer 31 can be used.

A color filter or the like can be used as the colored layer 97 . The colored layer 97 is the light emitting element 60
Place it so that it overlaps the display area of .

A black matrix or the like can be used as the light shielding layer 98 . The light shielding layer 98 is arranged so as to overlap with the insulating layer 35 .

Next, the surface of the manufacturing substrate 14 on which the transistor 80 and the like are formed and the surface of the manufacturing substrate 91 on which the colored layer 97 and the like are formed are attached to each other with an adhesive layer 99 (FIG. 8C). .

Next, the release layer 23 is irradiated with a laser beam to form a separation region 25 (FIG. 9A), and then a separation starting point is formed (FIG. 9B). Either the production substrate 14 or the production substrate 91 may be separated first. Here, an example is shown in which the production substrate 14 is separated before the production substrate 91 is separated.

The laser irradiation conditions for forming the isolation region 25 may be the same as the method described in the manufacturing method example 1. FIG.

As a method for forming the starting point of the separation, for example, there is a method of irradiating the inside of the separation region 25 of the separation layer 23a with a frame-shaped laser beam 66 from the formation substrate 14 side (the laser beam shown in FIG. 9C). See the light irradiation position 67). This method is suitable when a hard substrate such as glass is used for the production substrate 14 and the production substrate 91 .

There is no particular limitation on the laser used to form the starting point of separation. For example, a continuous wave laser or a pulsed wave laser can be used. The irradiation conditions (frequency, power density, energy density, beam profile, etc.) of the laser light are appropriately controlled in consideration of the thickness of the production substrate and the separation layer 23, the position of the separation region 25, the material, and the like.

In manufacturing method example 4, when laser light irradiation is performed to form the isolation region 25, the peeling layer 23 is provided with a portion irradiated with laser light and a portion not irradiated with laser light. A separation region 25 is formed in a portion irradiated with laser light to form the separation region 25 , and the peeling layer 23 is easily separated from the manufacturing substrate 14 . On the other hand, since there is no brittle portion in the separation layer 23 in the portion where the separation region is not formed, the separation layer 23 remains in a state where it is difficult to separate from the production substrate 14 .
Accordingly, it is possible to prevent the layer 21 to be peeled from being peeled off from the formation substrate 14 at an unintended timing. Similarly, when laser light irradiation for forming the separation region 94 is performed from the manufacturing substrate 91 , the peeling layer 93 is separated from the manufacturing substrate 91 unintentionally by providing a portion irradiated with the laser light and a portion not irradiated with the laser light. Separation at timing can be suppressed.

By forming the starting point of separation in only one of the separation layer 23 and the separation layer 93, the formation substrate 14 and the formation substrate 91 can be separated in separate steps. Accordingly, the yield of the separation process and the manufacturing process of the display device can be increased.

Next, after a separation starting point is formed in the separation layer 23 (separation region 25) from the formation substrate 14 side, the formation substrate 14 and the transistor 80 are separated (FIG. 10A). Here, an example in which the inner portion irradiated with the frame-shaped laser light 66 (which can also be referred to as the inner portion of the laser light irradiation region 67 shown in FIG. 9B) is peeled off from the manufacturing substrate 14 is shown. Further, in FIG. 10A, separation occurs in the adhesive layer 99 (adhesive layer 99
shows an example of cohesive failure), but is not limited to this. For example, the adhesive layer 99 may separate from the insulating layer 95 or the insulating layer 35 (also referred to as interfacial or adhesive failure) outside the irradiated region 67 .

Next, the peeling layer 23 exposed by separating from the production substrate 14 and the substrate 29 are bonded together with the adhesive layer 2 .
8 is used to bond them together (FIG. 10(B)). The substrate 29 functions as a supporting substrate of the display device.

Next, a separation starting point is formed in the separation layer 93 (separation region 94) (FIG. 11A).

In FIG. 11A, a sharp-edged instrument 65 such as a knife is inserted from the substrate 29 side to the inner side of the separation region 94 in the release layer 93 to make a frame-like cut. This is suitable when resin is used for the substrate 29 .

Alternatively, in the same manner as when the starting point of separation is formed in the separation layer 23, the separation layer 9 is removed from the production substrate 91 side.
3 may be irradiated with a laser beam in a frame shape.

By forming the separation starting point, the formation substrate 91 and the separation layer 93 can be separated at desired timing. Therefore, the timing of peeling can be controlled, and high peelability can be achieved. Accordingly, the yield of the separation process and the manufacturing process of the display device can be increased.

Next, the formation substrate 91 and the transistor 80 are separated (FIG. 11B). Here, an example is shown in which the inner portion where the frame-shaped cut is made is peeled off from the production substrate 91 .

Next, the release layer 93 exposed by separating from the production substrate 91 and the substrate 22 are bonded together with the adhesive layer 1 .
3 (FIG. 12(A)). The substrate 22 can function as a support substrate of the display device.

In FIG. 12A, light emitted from the light-emitting element 60 is extracted to the outside of the display device through the colored layer 97 and the peeling layer 93 . Therefore, it is preferable that the visible light transmittance of the peeling layer 93 is high.

The release layer 93 may be removed. Thereby, the light extraction efficiency of the light emitting element 60 can be further improved. In FIG. 12B, the release layer 93 is removed, and the insulating layer 9 is formed using the adhesive layer 13 .
5 shows an example in which a substrate 22 is attached.

A material that can be used for the adhesive layer 75 b can be applied to the adhesive layer 13 .

A material that can be used for the substrate 75 a can be applied to the substrate 22 .

Manufacturing Method Example 4 is an example of manufacturing a display device by performing the separation method of one embodiment of the present invention twice.
In one embodiment of the present invention, functional elements and the like that constitute a display device are all formed over a manufacturing substrate; Alignment accuracy is not required. Therefore, a flexible substrate can be easily attached.

As described above, when these display devices are manufactured, the peeling layer 23 and the peeling layer 93 are irradiated with laser light to decompose the resin molecules contained in the peeling layer 23 and the peeling layer 93.
By forming the isolation region 25 and the isolation region 94 which are fragile regions and separating them from the isolation region, the element formation region can be separated from the manufacturing substrate 14 and the manufacturing substrate 91. Therefore, the display of this embodiment mode is performed. A region between the adhesive layer 28 and the peeling layer 23 (the interface between the adhesive layer 28 and the peeling layer 23) and between the adhesive layer 13 and the peeling layer 93 included in the display device manufactured by applying the device manufacturing method (the interface between the adhesive layer 13 and the peeling layer 93) has a mass-to-charge ratio of 300 or more in LC/MS measurement, which is generated by decomposition of the peeling layer 23 or the peeling layer 93 due to irradiation with laser light. There is one or more substances derived from 950 or less ions. The peeling layer 23 and the peeling layer 93 in which molecules of these molecular weights are present have good peeling performance while suppressing unintended peeling due to moderate decomposition of the molecules. can be manufactured.

[Modification]
Manufacturing method example 4 (FIG. 18C) shows the case where the adhesive layer 99 is also formed outside the isolation region 25 and the isolation region 94 . The adhesion outside the separation region is high, and if the separation is performed as it is, the yield of separation may be lowered, such as the occurrence of defective separation.

Therefore, as shown in FIGS. 13A and 13B, by configuring the adhesive layer 99 so as not to overlap the outside of the isolation region 25 and the outside of the isolation region 94, it is possible to reduce delamination defects. becomes.

For example, if an adhesive with low fluidity or an adhesive sheet is used for the adhesive layer 99, the adhesive layer 9
It is easy to form 9 in an island shape (FIG. 13(A)).

Alternatively, a frame-shaped partition wall 96 may be formed, and an adhesive layer 99 may be filled in the inside surrounded by the partition wall 96 and cured (FIG. 13B).

When the partition 96 is used as a component of the display device, it is preferable to use a hardened resin for the partition 96 . At this time, it is preferable that the partition wall 96 does not overlap the outside of the isolation region 25 and the outside of the isolation region 94 either.

When the partition 96 is not used as a component of the display device, it is preferable to use an uncured or semi-cured resin for the partition 96 . At this time, the partition wall 96 may overlap one or both of the outside of the isolation region 25 and the outside of the isolation region 94 .

In this embodiment, an example is shown in which an uncured resin is used for the partition wall 96 and the partition wall 96 does not overlap the outside of the isolation region 25 and the outside of the isolation region 94 .

A method of forming separation starting points in a configuration in which the adhesive layer 99 does not overlap the outside of the isolation region 25 and the outside of the isolation region 94 will be described. An example of peeling the formation substrate 91 is described below.
A similar method can be used when the formation substrate 14 is separated.

In FIGS. 14A to 14E, the laser beam 66 for separating the production substrate 91 and the peeling layer 93
will be explained.

As shown in FIG. 14A, a starting point of separation can be formed by irradiating at least one region of the separation layer 93 where the separation region 94 and the adhesive layer 99 overlap with the laser beam 66 .

Since it is preferable that the force for separating the formation substrate 91 and the separation layer 93 is concentrated at the starting point of separation,
It is preferable to form the starting point of separation in the vicinity of the end portion of the adhesive layer 99 rather than in the central portion thereof. In particular, it is preferable to form the starting point of separation in the vicinity of the corners rather than in the vicinity of the sides, even in the vicinity of the ends.

14B to 14E show an example of the laser beam irradiation region 67. FIG.

FIG. 14B shows a laser beam irradiation region 67 at one corner of the adhesive layer 99 .

By continuously or intermittently irradiating the laser beam, a solid-line or broken-line separation starting point can be formed. In FIG. 14C, three laser light irradiation regions 67 are shown at the corners of the adhesive layer 99 . FIG. 16D shows an example in which the laser beam irradiation region 67 is in contact with one side of the adhesive layer 99 and extends along one side of the adhesive layer 99 . As shown in FIG. 14(E),
The laser beam irradiation region 67 may be located not only in the region where the adhesive layer 99 and the separation region 94 overlap, but also in the region where the non-cured partition wall 96 and the separation region 94 overlap.

After that, the formation substrate 91 and the separation layer 93 can be separated. Note that part of the partition 96 may remain on the formation substrate 14 side. The partition wall 96 may be removed, or the next step may be performed without removing it.

[Configuration example 2 of display device]
FIG. 15A is a top view of the display device 10B. FIG. 15B is an example of a cross-sectional view of the display portion 381 of the display device 10B and a cross-sectional view of the connection portion with the FPC 372 .

The display device 10B can be manufactured using the manufacturing method example 5 described above. Display device 10B
can be held in a bent state or repeatedly bent.

The display device 10B has substrates 22 and 29 . The substrate 22 side is the display surface side of the display device 10B. The display device 10B has a display section 381 and a drive circuit section 382 . An FPC 372 is attached to the display device 10B.

The conductive layer 86c and the FPC 372 are electrically connected via the connector 76 (FIG. 15).
(B)). The conductive layer 86c can be formed using the same material and the same process as the source and drain of the transistor.

As described above, when these display devices are manufactured, the release layer 23 is irradiated with laser light to decompose the resin molecules contained in the release layer 23, and the separation region 25, which is a brittle region, is formed.
is formed, and the separation layer 93 is separated from the separation region, whereby the element formation region can be separated from the formation substrate 14 . Therefore, the region between the adhesive layer 28 and the peeling layer 23 (the adhesive layer 28 and the peeling layer 23 ) included in the display device manufactured by applying the method for manufacturing the display device of this embodiment mode.
LC generated by decomposing the peeling layer 23 due to the irradiation of the laser beam.
/MS measurement, one or more substances derived from ions having a mass-to-charge ratio of 300 to 950 are present. The release layer 23 in which molecules of these molecular weights are present has good release performance while suppressing unintended release due to moderate decomposition of the molecules.
A display device can be manufactured with a high yield.

This embodiment can be appropriately combined with other embodiments. Further, in this specification, when a plurality of configuration examples are shown in one embodiment, the configuration examples can be combined as appropriate.

(Embodiment 1)
In this embodiment, a display device of one embodiment of the present invention and a manufacturing method thereof will be described with reference to drawings.

The display device of this embodiment mode includes a first display element that reflects visible light and a second display element that emits visible light.

The display device of this embodiment mode has a function of displaying an image using one or both of light reflected by the first display element and light emitted by the second display element.

An element that reflects external light for display can be used as the first display element. Since such an element does not have a light source, power consumption during display can be extremely reduced.

A reflective liquid crystal element can be typically used for the first display element. or the first
Shutter type MEMS (Micro Electro Mech
In addition to optical interference type MEMS elements, microcapsule type, electrophoresis type, electrowetting type, electronic liquid powder (registered trademark) type, and the like can be used.

A light-emitting element is preferably used for the second display element. The brightness and chromaticity of the light emitted by such a display element is not affected by external light, so it has high color reproducibility (a wide color gamut), high contrast, and vivid display. can be done.

For the second display element, for example, an OLED (Organic Light Emitting
Diode), LED (Light Emitting Diode), QLED (Q
A self-luminous light emitting element such as a uantum-dot Light Emitting Diode) can be used.

The display device of this embodiment has a first mode for displaying an image using only the first display element,
It has a second mode in which an image is displayed using only the second display element and a third mode in which an image is displayed using the first display element and the second display element, and these modes are used. It can be switched automatically or manually.

In the first mode, an image is displayed using the first display element and external light. Since the first mode does not require a light source, it is a very low power consumption mode. For example, when a sufficient amount of outside light enters the display device (eg, in a bright environment), display can be performed using light reflected by the first display element. For example, it is effective when the outside light is sufficiently strong and the outside light is white light or light in the vicinity thereof. The first mode is a mode suitable for displaying characters. In addition, since the first mode uses light reflected from outside light, it is possible to perform display that is easy on the eyes.
The effect is that the eyes are less likely to get tired.

In the second mode, an image is displayed using light emitted by the second display element. Therefore, it is extremely vivid (high contrast and high color reproducibility) regardless of the illuminance or the chromaticity of the outside light.
can be displayed. For example, it is effective when the illuminance is extremely low, such as at night or in a dark room. In addition, when the surroundings are dark, the user may feel dazzled by bright display. In order to prevent this, it is preferable to perform display with suppressed luminance in the second mode. As a result, power consumption can be reduced in addition to suppressing glare. The second mode is a mode suitable for displaying vivid images (still images and moving images).

In the third mode, display is performed using both reflected light from the first display element and light emission from the second display element. Power consumption can be suppressed more than in the second mode while displaying more vividly than in the first mode. For example, it is effective when the illuminance is relatively low, such as under indoor lighting, in the morning or in the evening, or when the chromaticity of outside light is not white. In addition, by using light that is a mixture of reflected light and emitted light, it is possible to display an image that makes one feel as if one is looking at a painting.

With such a structure, a highly visible and convenient display device or an all-weather display device can be realized regardless of the brightness of the surroundings.

The display device of this embodiment mode includes a plurality of first pixels each having a first display element and a plurality of second pixels each having a second display element. The first pixels and the second pixels are preferably arranged in a matrix.

Each of the first pixel and the second pixel can have one or more sub-pixels. For example, the pixel may have one sub-pixel (such as white (W)), three sub-pixels (three colors of red (R), green (G), and blue (B), or yellow (Y), cyan (C), and magenta (M)), or a configuration with four sub-pixels (red (
R), green (G), blue (B), and white (W), or red (R), green (G),
blue (B), yellow (Y), etc.) can be applied.

The display device of this embodiment mode can have a structure in which both the first pixel and the second pixel perform full-color display. Alternatively, the display device of this embodiment mode can have a structure in which black-and-white display or grayscale display is performed in the first pixel, and full-color display is performed in the second pixel. Monochrome display or grayscale display using the first pixels is suitable for displaying information that does not require color display, such as document information.

(Embodiment 2)
In this embodiment, a CA that can be used for the transistor disclosed in one embodiment of the present invention is described.
The configuration of C (Cloud-Aligned Composite)-OS will be described.

A CAC-OS is, for example, one structure of a material in which elements constituting a metal oxide are unevenly distributed with a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or in the vicinity thereof. In the following description, one or more metal elements are unevenly distributed in the metal oxide, and the region containing the metal element has a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or a size in the vicinity thereof. The mixed state is also called mosaic or patch.

Note that the metal oxide preferably contains at least indium. Indium and zinc are particularly preferred. In addition to them, element M (M is gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium , tantalum, tungsten, or magnesium).

For example, an In-M-Zn oxide having a structure of CAC-OS refers to an indium oxide (hereinafter referred to as InO _X1 (X1 is a real number greater than 0)) or an indium zinc oxide (hereinafter referred to as In _X2 Zn _Y2 O _Z2 (where X2, Y2, and Z2 are real numbers greater than 0), an oxide of element M (hereinafter referred to as MO _X3 (where X3 is a real number greater than 0)),
or zinc oxide of element M (hereinafter M _X4 Zn _Y4 O _Z4 (where X4, Y4, and Z4 are 0
real number greater than ). ) and so on, the material is separated into a mosaic shape, and the mosaic InO _X1 or In _X2 Zn _Y2 O _Z2 is distributed in the film (hereinafter also referred to as a cloud shape).

That is, in the In-M-Zn oxide having the structure of CAC-OS, a region containing MO _X3 as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component are mixed. It is a metal oxide that contains Therefore, metal oxides are sometimes described as composite metal oxides. In this specification, for example, the first region means that the atomic ratio of In to the element M in the first region is greater than the atomic ratio of In to the element M in the second region. Assume that the concentration of In is higher than that of the region No. 2.

Note that a metal oxide having a structure of CAC-OS does not include a stacked structure of two or more films with different compositions. For example, it does not include a structure consisting of two layers, a film containing In as a main component and a film containing Ga as a main component.

Specifically, CAC-OS in In--Ga--Zn oxide (In--
Ga--Zn oxide may be specifically referred to as CAC-IGZO. ) will be explained. I
CAC-OS in n-Ga-Zn oxide is InO _X1 or In _X2 Zn _Y2 O
_Z2 and gallium oxide (hereinafter referred to as GaO _X5 (X5 is a real number greater than 0)),
Alternatively, gallium zinc oxide (hereinafter referred to as Ga _X6 Zn _Y6 O _Z6 (X6, Y6, and Z6 are real numbers greater than 0)) and the like are separated into a mosaic shape, and a mosaic InO _X1 or In _X2 Zn _Y2 O _Z2 is a cloud-like metal oxide.

That is, the CAC-OS in the _{In--Ga--Zn oxide has a structure in which a region containing GaO.sub.2X5 as a main component and a region containing In.sub.2X2ZnY2O.sub.2 or InO.sub.2X1 as a} main component are mixed. It is a composite metal oxide with In addition, the region containing GaO _X5 as the main component and the region containing In _X
2 Zn _Y2 O _Z2 or a region containing InO _X1 as a main component may not be able to observe a clear boundary in some cases.

Note that IGZO is a common name, and may refer to one compound of In, Ga, Zn, and O. Representative examples include InGaO ₃ (ZnO) _m1 (m1 is a natural number), or In _(
1+x0) Ga _(1−x0) O ₃ (ZnO) _m0 (−1≦x0≦1, m0 is an arbitrary number).

The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. note that,
The CAAC structure is a layered crystal structure in which a plurality of IGZO nanocrystals have a c-axis orientation and are connected without being oriented in the ab plane.

In this specification and the like, CAC-IGZO means a metal oxide containing In, Ga, Zn, and O, in which a plurality of regions containing Ga as a main component and a plurality of regions containing In as a main component are
It can be defined as a metal oxide that is randomly dispersed in a mosaic pattern.

The crystallinity of CAC-OS in In--Ga--Zn oxide can be evaluated by electron diffraction. For example, in an electron beam diffraction pattern image, a ring-shaped region with high brightness is observed. Also, a plurality of spots may be observed in a ring-shaped area.

The CAC-OS in the In--Ga--Zn oxide has a structure different from that of the IGZO compound in which metal elements are uniformly distributed, and has properties different from those of the IGZO compound. That is, In-Ga
-The CAC-OS in the Zn oxide has a region mainly composed of GaO _X5 and the like, and a region containing In _X2
A region containing _ZnY2OZ2 or _InO2X1 as a main component is separated from each other, and the regions containing each element as a main component have _a mosaic structure.

Gallium may be replaced with aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium. When it is contained, the CAC-OS has a region that is partly observed in the form of nanoparticles containing the metal element as a main component and a region that is partly observed in the form of nanoparticles containing In as a main component. are distributed randomly in a mosaic pattern.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is GaO _X5
is a region with high conductivity compared to a region containing, for example, as a main component. That is, In _X2 Zn _Y
Conductivity develops when carriers flow through a region containing ₂ O _Z2 or InO _{2 X1} as a main component. Therefore, a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is distributed in the metal oxide in a cloud shape, so that a high field effect mobility (μ) can be realized.

On the other hand, a region containing GaO _X5 or the like as a main component is In _X2 Zn _Y2 O _Z2 or InO _X
This region has a higher insulating property than the region containing ₁ as the main component. In other words, by distributing the region mainly composed of GaO _{2 X5} or the like in the metal oxide, it is possible to suppress leakage current and realize good switching operation.

Therefore, when the CAC-OS in In--Ga--Zn oxide is used for a semiconductor element, Ga
Insulation due to O _{2 X5} and the like and conductivity due to In _X2 Zn _Y2 O _Z2 or InO _{2 X1} act in a complementary manner, resulting in high on-current (I _on ) and high field effect mobility ( μ), and low off-current (I _off ) can be achieved.

Semiconductor devices using CAC-OS in In--Ga--Zn oxide have high reliability. Therefore, CAC-OS in In--Ga--Zn oxide is most suitable for various semiconductor devices including displays.

This embodiment can be appropriately combined with other embodiments.

(Embodiment 3)
In this embodiment, a display module and an electronic device of one embodiment of the present invention will be described.

A display module 8000 shown in FIG. 16 includes a touch panel 8004 connected to an FPC 8003, a display panel 8006 connected to an FPC 8005, a frame 8009, a printed circuit board 8010, and a battery 8011 between an upper cover 8001 and a lower cover 8002.
have

For example, the display device manufactured using the separation method of one embodiment of the present invention is used as the display panel 8006.
can be used for Thereby, the display module can be manufactured with a high yield.

The upper cover 8001 and the lower cover 8002 are connected to the touch panel 8004 and the display panel 8004.
006, the shape and dimensions can be changed as appropriate.

As the touch panel 8004, a resistive or capacitive touch panel can be used by overlapping the display panel 8006 with it. Alternatively, the display panel 8006 can have a touch panel function without providing the touch panel 8004 .

The frame 8009 has a function of protecting the display panel 8006 as well as a function as an electromagnetic shield for blocking electromagnetic waves generated by the operation of the printed circuit board 8010 . The frame 8009 may also function as a heat sink.

The printed circuit board 8010 has a power supply circuit, a signal processing circuit for outputting a video signal and a clock signal. A power supply for supplying power to the power supply circuit may be an external commercial power supply, or may be a power supply using a battery 8011 provided separately. The battery 8011 is
It can be omitted when a commercial power supply is used.

In addition, the display module 8000 may be additionally provided with members such as a polarizing plate, a retardation plate, and a prism sheet.

According to one embodiment of the present invention, a highly reliable electronic device having a curved surface can be manufactured. Further, according to one embodiment of the present invention, a flexible and highly reliable electronic device can be manufactured.

Examples of electronic devices include televisions, desktop or notebook personal computers, computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones, mobile game machines, personal digital assistants, audio Examples include playback devices and large game machines such as pachinko machines.

Further, the display device of one embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Therefore, it can be suitably used for portable electronic devices, wearable electronic devices (wearable devices), electronic book terminals, and the like.

A mobile information terminal 800 shown in FIGS. 17A and 17B includes a housing 801, a housing 802, a display unit
03, a display portion 804, a hinge portion 805, and the like.

The housing 801 and the housing 802 are connected by a hinge portion 805 . The portable information terminal 800
From the folded state (FIG. 17(A)), it can be unfolded as shown in FIG. 17(B).

The display device manufactured using the separation method of one embodiment of the present invention is separated into the display portion 803 and the display portion 80.
4 can be used for at least one of them. Accordingly, a portable information terminal can be manufactured with a high yield.

Each of the display units 803 and 804 can display at least one of document information, still images, moving images, and the like. When document information is displayed on the display portion, the portable information terminal 800 can be used as an electronic book terminal.

Since portable information terminal 800 can be folded, it has high portability and excellent versatility.

The housing 801 and the housing 802 may have a power button, an operation button, an external connection port, a speaker, a microphone, and the like.

A mobile information terminal 810 illustrated in FIG. 17C includes a housing 811, a display portion 812, and operation buttons 81.
3. It has an external connection port 814, a speaker 815, a microphone 816, a camera 817, and the like.

A display device manufactured using the separation method of one embodiment of the present invention can be used for the display portion 812 . Accordingly, a portable information terminal can be manufactured with a high yield.

Portable information terminal 810 includes a touch sensor in display portion 812 . All operations such as making a call or inputting characters can be performed by touching the display unit 812 with a finger, a stylus, or the like.

Further, by operating the operation button 813 , the power can be turned on and off, and the type of image displayed on the display portion 812 can be switched. For example, it is possible to switch from the mail creation screen to the main menu screen.

In addition, by providing a detection device such as a gyro sensor or an acceleration sensor inside the mobile information terminal 810, the orientation (vertical or horizontal) of the mobile information terminal 810 is determined, and the screen display orientation of the display unit 812 is determined. can be switched automatically. In addition, the orientation of the screen display can be switched by touching the display portion 812, operating the operation button 813, voice input using the microphone 816, or the like.

The mobile information terminal 810 has one or more functions selected from, for example, a telephone, a notebook, an information viewing device, and the like. Specifically, it can be used as a smartphone. Personal digital assistant 810 is capable of executing various applications such as mobile phone, e-mail, text viewing and composition, music playback, video playback, Internet communication, and games, for example.

A camera 820 illustrated in FIG. 17D includes a housing 821, a display portion 822, an operation button 823, a shutter button 824, and the like. A detachable lens 826 is attached to the camera 820 .

A display device manufactured using the separation method of one embodiment of the present invention can be used for the display portion 822 . Thereby, cameras can be manufactured with a high yield.

Although the camera 820 is configured such that the lens 826 can be removed from the housing 821 and replaced, the lens 826 and the housing 821 may be integrated.

The camera 820 can capture still images or moving images by pressing the shutter button 824 . Further, the display unit 822 has a function as a touch panel, and the display unit 82
It is also possible to take an image by touching 2 .

Note that the camera 820 can be separately equipped with a strobe device, a viewfinder, and the like. Alternatively, these may be incorporated in the housing 821 .

18A to 18E are diagrams showing electronic devices. These electronic devices are housed in a housing 9000
, display unit 9001, speaker 9003, operation keys 9005 (including a power switch or an operation switch), connection terminals 9006, sensors 9007 (force, displacement, position, speed, acceleration,
Angular velocity, number of rotations, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays. included), a microphone 9008, and the like.

A display device manufactured using the separation method of one embodiment of the present invention can be suitably used for the display portion 9001 . Accordingly, electronic devices can be manufactured with a high yield.

The electronic devices illustrated in FIGS. 18A to 18E can have various functions. For example, a function to display various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a calendar, a function to display the date or time, a function to control processing by various software (programs), Wireless communication function, function to connect to various computer networks using wireless communication function, function to transmit or receive various data using wireless communication function, read and display programs or data recorded on recording media It can have a function to display on the part, etc. Note that the functions of the electronic devices shown in FIGS. 18A to 18E are not limited to these, and may have other functions.

18A is a perspective view of a wristwatch-type mobile information terminal 9200, and FIG. 18B is a perspective view of a wristwatch-type mobile information terminal 9201, respectively.

A mobile information terminal 9200 shown in FIG. 18A can execute various applications such as mobile phone, e-mail, reading and creating sentences, playing music, Internet communication, and computer games. Further, the display portion 9001 has a curved display surface, and display can be performed along the curved display surface. In addition, the mobile information terminal 9200 is capable of performing short-range wireless communication according to communication standards. For example, by intercommunicating with a headset capable of wireless communication, hands-free communication is also possible. In addition, the portable information terminal 9200 has a connection terminal 9006 and can directly exchange data with another information terminal through a connector. Also, charging can be performed through the connection terminal 9006 .
Note that the charging operation may be performed by wireless power supply without using the connection terminal 9006 .

Unlike the portable information terminal shown in FIG. 18A, the display surface of the display portion 9001 of the portable information terminal 9201 shown in FIG. 18B is not curved. In addition, the outer shape of the display portion of the portable information terminal 9201 is non-rectangular (circular in FIG. 18B).

18C to 18E are perspective views showing a foldable personal digital assistant 9202. FIG. Note that FIG. 18C is a perspective view of the portable information terminal 9202 in an unfolded state, and FIG.
18E is a perspective view of the portable information terminal 9202 in a state in which it changes from one of the unfolded state and the folded state to the other, and FIG. 18E is a perspective view of the portable information terminal 9202 in the folded state.

The portable information terminal 9202 has excellent portability in the folded state, and has excellent display visibility due to a seamless wide display area in the unfolded state. A display portion 9001 included in the portable information terminal 9202 is supported by three housings 9000 connected by hinges 9055 .
By bending between the two housings 9000 via the hinge 9055, the portable information terminal 9
202 can be reversibly transformed from an unfolded state to a folded state. For example, the mobile information terminal 9202 can be bent with a curvature radius of 1 mm or more and 150 mm or less.

This embodiment can be appropriately combined with other embodiments.

In this embodiment, a method of forming a release layer by forming a polyimide thin film on a glass substrate, adhering a release film to the polyimide, and irradiating a laser from the glass substrate side will be described. A solution of soluble polyimide on a glass substrate (product number at Tochigi Plant: S
O0100001) was dropped in an appropriate amount, and a film was formed by spin coating. After film formation, the substrate is 400
℃ for 1 hour, and after the baking, a peeling film was adhered. As a bonding method, an adhesive (Nissin Resin, CEP05) is applied linearly on polyimide, and a 125 μm PET film (Panac Co., Ltd., CT100/Lumirror 125UF83) is placed as a release film, and stretched with a laminator to adhere. let me Then, an excimer laser (wavelength: 308 nm) was irradiated from the glass substrate side so that the energy density was 439 (mJ/cm ² ). After irradiation, the release layer was separated from the glass substrate by notching the release film.

For the peeling film having the separated layer to be peeled and the glass substrate after peeling, LC/MS analysis was performed on the surface of the glass substrate and the surface of the peeling layer on the peeling film side. A release film having a layer to be peeled to be analyzed and a glass substrate after separating the layer to be peeled are cut into an arbitrary size, and the surface of the glass substrate on which the layer to be peeled was formed and the peeling having the layer to be peeled. The surface of the film layer to be peeled was washed 3 times with 15 drops of a mixed solution of acetonitrile and chloroform at a volume ratio of 7:3, and the obtained washing liquid was used as a measurement sample. As a solvent used for washing away, a mixed solution of acetonitrile and 1,1,1,3,3,3-hexafluoro-2-propanol (abbreviation: HFIP) at a volume ratio of 7:3 was also used. As a reference, the surfaces of the release film (PET\CEP05) and the glass substrate were similarly washed with the mixed solvent of the two types, and used as a reference sample.

For the two types of samples prepared as above and two types of reference samples, LC
/MS analysis was performed. In the LC/MS analysis, LC (liquid chromatography) separation was performed by Acquity UPLC manufactured by Waters, and MS analysis (mass spectrometry) was performed by Xevo G2 Tof MS manufactured by Waters. The column used for LC separation is Acquity
UPLC BEH C8 (2.1×100 mm 1.7 μm), column temperature 40° C.
and As for the mobile phases, mobile phase A was acetonitrile and mobile phase B was 0.1% formic acid aqueous solution. In addition, the injection amount of the sample was set to 5.0 μL.

For LC separation, a gradient method was used in which the composition of the mobile phase was changed.
30:70 mobile phase A:mobile phase B for up to 9 minutes, then the composition is changed so that the ratio of mobile phase A:mobile phase B at 9 minutes is 95:5. A linear gradient was applied to , then held at the same rate for up to 15 minutes.

Electrospray ionization was used for MS analysis.
Zation (abbreviation: ESI) ionization is performed, and the capillary voltage is 3.0107
5 kV, sample cone voltage of 30 V, detection was performed in positive and negative modes. The mass range for measurement was m/z=100-1200. FIG. 19 shows a chromatograph of a PDA (photodiode array) detector obtained by the LC/MS analysis performed as described above. Table 1 summarizes the area ratios of the peaks detected in FIG. Table 1 shows only the mass-to-charge costs detected in the negative mode, since no ions were detected in the positive mode.

As can be seen from Table 1, a large number (5 or more, preferably 10 or more) of substances derived from ions having a mass-to-charge ratio of 300 or more and 950 or less were detected from the separation interface of the peeling layer in a plurality of LC/MS measurements. This substance is produced by decomposition of the polyimide of the release layer by absorbing the laser.

FIG. 20 shows the absorptivity of laser light when a polyimide film formed in the same manner as in the above experiment was similarly irradiated with laser light having a wavelength of about 308 nm. Under the above conditions, the polyimide film is
It shows an absorptance of 94.3%, indicating that most of the irradiated laser light is absorbed. That is, by absorbing the irradiated laser light, the polyimide film decomposes, resulting in LC/M
It is thought that in the S measurement, many substances derived from ions with a mass-to-charge ratio of 300 or more and 950 or less were detected.

Here, the soluble polyimide solution used (product number at Tochigi Plant: SO0100001
) will be described for the LC/MS analysis of the low-molecular-weight components contained in. When the soluble polyimide solution and chloroform were mixed at a volume ratio of 1:1, deposition of polyimide was confirmed. The mixture was allowed to stand for 1 hour until the polyimide precipitated.

Similarly, Comparative Sample 2 was prepared using 1,1,1,3,3,3-hexafluoro-2-propanol (abbreviation: HFIP) instead of chloroform.

LC/MS analysis was performed on the two comparative samples prepared as described above. LC/
The apparatus and analysis conditions used for the MS analysis are the same as those used for analyzing the release layer surface described above.

A PDA (photodiode array) detector chromatograph obtained by LC/MS analysis is shown in FIG. 21A shows the results of Comparative Sample 1, and FIG. 21B shows the results of Comparative Sample 2. FIG. Nothing was detected from the PDA chromatograph as can be seen from Figures 21 (A) and (B). Meanwhile, some ions were detected by the MS detector. Table 2 summarizes the detected mass-to-charge ratios and retention times. Table 2 shows only the mass-to-charge costs detected in negative mode, since no ions were detected in positive mode.

As can be seen from Table 2, it was confirmed that the soluble polyimide solution contained several types of low-molecular-weight components that were soluble in chloroform and HFIP, to the extent that they could be detected by MS.

Comparing this comparative sample with the peeled sample, the low molecular weight components with a mass-to-charge ratio (m/z) of 300 or more and 950 or less detected in the peeled sample were contained in the soluble polyimide solution. It was confirmed that it was not a product, but occurred in the peeling process. Since the low molecular weight component generated in the peeling step is present at the peeling interface, it is considered that good peelability was obtained by notching the production of the low molecular weight component.

Therefore, the production of these substances causes embrittlement of the part, and peeling occurs at the embrittled part as a notch. The peeling method of the present invention, in which an embrittled layer is formed from degraded polyimide, can provide a peeling portion when peeling is desired. In other words, it is characterized in that the layer to be peeled can be held on the substrate in a step where peeling should not be performed. Therefore, the substrate prepared by using the peeling method of the present invention can provide a layer to be peeled at low cost, short tact time, and high reliability.

10A display device 10B display device 13 adhesive layer 14 production substrate 21 layer to be peeled 22 substrate 23 peeling layer 24 resin layer 25 isolation region 28 adhesive layer 29 substrate 31 insulating layer 32 insulating layer 33 insulating layer 34 insulating layer 35 insulating layer 40 transistor 41 Conductive layer 43a Conductive layer 43b Conductive layer 43c Conductive layer 44 Metal oxide layer 45 Conductive layer 49 Transistor 60 Light emitting element 61 Conductive layer 62 EL layer 63 Conductive layer 64 Cut 65 Tool 66 Laser beam 67 Irradiation area 74 Insulating layer 75 Protective layer 75a Substrate 75b Adhesive layer 76 Connector 80 Transistor 81 Conductive layer 82 Insulating layer 83 Metal oxide layer 84 Insulating layer 85 Conductive layer 86a Conductive layer 86b Conductive layer 86c Conductive layer 91 Manufacturing substrate 93 Separation layer 94 Separation region 95 Insulating layer 96 Partition 97 Colored layer 98 Light shielding layer 99 Adhesive layer 372 FPC
381 display unit 382 drive circuit unit 800 portable information terminal 801 housing 802 housing 803 display unit 804 display unit 805 hinge unit 810 portable information terminal 811 housing 812 display unit 813 operation button 814 external connection port 815 speaker 816 microphone 817 camera 820 Camera 821 Housing 822 Display Unit 823 Operation Button 824 Shutter Button 826 Lens 8000 Display Module 8001 Upper Cover 8002 Lower Cover 8003 FPC
8004 Touch panel 8005 FPC
8006 display panel 8009 frame 8010 printed circuit board 8011 battery 9000 housing 9001 display unit 9003 speaker 9005 operation key 9006 connection terminal 9007 sensor 9008 microphone 9055 hinge 9200 mobile information terminal 9201 mobile information terminal 9202 mobile information terminal

Claims (1)

forming a first resin layer containing polyimide as a main component on the production substrate;
forming a layer to be peeled on the first resin layer;
A separation region is formed by irradiating the first resin layer with a laser beam,
A peeling method for separating the formation substrate and the layer to be peeled at the separation region.

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