JP2007288078A - Flexible electronic device and manufacturing method thereof - Google Patents

Abstract

The present invention provides a flexible electronic device that suppresses cracks that occur during transfer, improves resistance to bending stress of the obtained device, and has excellent display quality and electrical characteristics.
A method for manufacturing a flexible electronic device according to the present invention is a method for manufacturing a flexible electronic device, comprising: forming a base insulating film on a first substrate; and patterning a semiconductor layer on the base insulating film. Forming a gate insulating film on the base insulating film and the semiconductor layer pattern; forming a gate electrode pattern on the gate insulating film; and Forming a first interlayer insulating film on the gate electrode pattern; and forming the base insulating film, the gate insulating film, and the first interlayer insulating film in a portion where the semiconductor layer or the gate electrode pattern is not formed. And removing the film to form an island in the insulating film stack.
[Selection] Figure 6

Description

  The present invention relates to a flexible electronic device and a method for manufacturing the same, and more particularly to a flexible electronic device and a method for manufacturing the same in which cracks generated during transfer are suppressed and resistance to bending stress of the obtained device is improved.

A flexible electronic device is a device in which a thin film transistor is mounted on a plastic substrate, and application to electronic paper, an IC card, an IC tag, and the like has been studied by taking advantage of its flexibility.
For example, an electrophoretic display sheet (so-called EPD display device) in which an electrophoretic element is formed on a plastic transparent substrate is a flexible display device using electrophoresis in which particles dispersed in a solvent move by application of voltage. Compared to LCD (liquid crystal display), it is easier to process and handle, and is expected to be used for portable devices and information devices.

As a manufacturing method of a flexible electronic device, for example, a method of transferring a thin film device layer formed on an inorganic substrate to a flexible substrate has been proposed (Patent Document 1).
Japanese Patent Laid-Open No. 10-125931

However, when the process of transferring the thin film device layer to the flexible substrate or bending the obtained device, the internal stress generated by thermal stress or bending stress is not released, and stress concentration occurs locally, cracks and wiring patterns There is a problem that disconnection is caused.
These are differences in thermal expansion coefficient and Young's modulus between each layer in thin film device layers composed of inorganic insulating layers, organic insulating layers, amorphous layers, metal layers, etc., and thermal expansion coefficients between flexible substrates and thin film device layers. It is thought that this is due to the difference in Young's modulus. For example, when transferring a thin film device layer by thermocompression bonding, thermal stress is applied to the entire device, and undulation may occur around the pattern formed of a member having a high thermal expansion coefficient due to the difference in thermal expansion coefficient of each layer. is there.
Further, there is a problem that a crack generated from one place easily propagates through the inorganic insulating layer and spreads over the entire thin film device layer. In particular, cracks tend to occur and propagate easily in an inorganic insulating layer having a high Young's modulus.

  Accordingly, the present invention provides a flexible electronic device that suppresses cracks that occur when a thin film device layer is transferred to a flexible substrate, improves resistance to bending stress of the resulting device, and has excellent display quality and electrical characteristics. The purpose is to provide.

  The present invention provides (1) a method for manufacturing a flexible electronic device, the step of forming a base insulating film on a first substrate, the step of forming a semiconductor layer pattern on the base insulating film, and the base Forming a gate insulating film on the insulating film and the semiconductor layer pattern; forming a gate electrode pattern on the gate insulating film; and forming a gate electrode pattern on the gate insulating film and the gate electrode pattern. A step of forming an interlayer insulating film, and an insulating film stack by removing the base insulating film, the gate insulating film, and the first interlayer insulating film in a portion where the pattern of the semiconductor layer or the gate electrode is not formed And (2) a method of manufacturing a flexible electronic device including: forming a body into an island; and (2) over the island-insulated insulating film stack and on the first substrate. The method for manufacturing a flexible electronic device according to (1), further including a step of forming a source / drain electrode on the portion from which the film stack is removed; (3) the base insulation on the first substrate; The step of forming a film includes a step of forming a separation layer on the first substrate and a step of forming the base insulating film on the separation layer, and the pattern of the base insulating film and the semiconductor layer Detaching the thin film element layer including the gate insulating film, the pattern of the gate electrode, and the first interlayer insulating film from the first substrate, and transferring the thin film element layer to the second substrate. The method of manufacturing a flexible electronic device according to claim 1, further comprising: (4) a flexible electronic device, a flexible first substrate, and an island shape on the first substrate Formed into A flexible electronic device comprising: an insulating film laminated body comprising an insulating film laminated body including a base insulating film, a gate insulating film, and a first interlayer insulating film, and including a semiconductor layer and / or gate electrode pattern (5) a source / drain electrode formed on the insulating film stack formed in the island shape and on a portion of the first substrate where the insulating film stack is not formed; The flexible electronic device according to (4), including:

  “Flexible electronic devices” include displays, televisions, electronic books, electronic papers, wristwatches, electronic notebooks, calculators, mobile phones, personal digital assistants, etc., equipped with display units that use electrophoretic materials. IC cards, IC tags, and moreover, for example, flexible paper / film-like objects, those belonging to real estate such as wall surfaces to which these objects are attached, vehicles, flying objects, ships and other moving objects Including those that belong.

According to the present invention, the insulating film other than the part necessary for fulfilling the function as an electronic device is removed by etching, and the insulating film stack is islanded and separated from each other, so that the thin film device layer is transferred to the flexible substrate. In addition, when the obtained device is bent, the internal stress can be released and the stress concentration can be relaxed. As a result, the occurrence of cracks or the destruction of the drive circuit of the device can be suppressed, and the transfer yield and the reliability after manufacture can be improved.
Further, even if a crack occurs in one island, it can be prevented from propagating to the surrounding island.

  The following embodiment is an example for explaining the present invention, and is not intended to limit the present invention only to this embodiment. The present invention can be implemented in various forms without departing from the gist thereof.

  1-12 is a figure explaining each process of the manufacturing method of the flexible electronic device which concerns on embodiment of this invention.

  As shown in FIG. 1, a separation layer 120 is formed on a flexible substrate 100, a base insulating film 142 is formed thereon, and semiconductor layer patterns 143b and 143c are formed thereon.

  The flexible substrate 100 is made of resin, for example.

  The separation layer 120 is preferably made of a-Si (amorphous silicon). Alternatively, the separation layer 120 may be made of various oxide ceramics such as silicon oxide or silicate compound, titanium oxide or titanate compound, zirconium oxide or zirconate compound, lanthanum oxide or lanthanum oxide compound, PZT, PLZT, PLLZT, PBZT, etc. It may be made of ceramics or dielectric (ferroelectric), nitride ceramics such as silicon nitride, aluminum nitride and titanium nitride, organic polymers, alloys and the like.

The separation layer 120 can be formed by, for example, CVD methods (MOCVD, low pressure CVD, ECR-CVD, etc.), CVD, vapor deposition, molecular beam vapor deposition (MB), sputtering, ion plating, PVD and other various gas phase film formation methods, Various plating methods such as electroplating, immersion plating (dipping), electroless plating, Langmuir ProJet (LB) method, spin coating, spray coating, roll coating and other coating methods, various printing methods, transfer methods, inkjet methods, Performed by powder jet method or the like.
When the separation layer 120 is made of amorphous silicon, it is preferably formed by a CVD method, and when the separation layer 120 is made of ceramics or an organic polymer, it is preferably formed by spin coating. .

The formation of the base insulating film 142 is performed by, for example, a CVD method. The base insulating film 142 is preferably made of SiO ₂ or Si ₃ N ₄ .
Formation of the patterns 143b and 143c of the semiconductor layer (143) is performed by first depositing a-Si on the base insulating film 142 by a CVD method or the like, and then performing annealing by irradiating laser light from above. Is recrystallized to obtain a polysilicon layer. Next, the polysilicon layer is patterned to obtain semiconductor layer patterns 143b and 143c made of polysilicon islands.

  Next, as shown in FIG. 2, source / drain regions are formed. The mask layer 171 masks the entire semiconductor layer pattern 143c and a part of the semiconductor layer pattern 143b. For example, phosphorus is ion-implanted in a high concentration (n +) source into a region to be an n-type TFT of the semiconductor layer pattern 143b. An n + layer 144 that is a drain region (HDD region) is formed.

Next, as shown in FIG. 3, a gate insulating film 153 made of, for example, SiO _{2 is} formed on the base insulating film 142 and the semiconductor layer patterns 143b and 143c by, for example, a CVD method.

Next, as shown in FIG. 4, a pattern of the gate electrode 152 is formed on the gate insulating film 153. For the gate electrode 152, a metal such as aluminum or tantalum, or a material such as polysilicon can be used.
Further, the semiconductor layer pattern 143c is masked by the mask layer 172, and, for example, phosphorus is ion-implanted at a low concentration into a predetermined region of 143b, and an n− layer which is a low concentration (n−) source / drain region (LDD region). 145 is formed.

  Next, as shown in FIG. 5, using the mask layer 173 and the gate electrode 152 as a mask, for example, boron (B) ions are implanted into a predetermined region of the semiconductor layer pattern 143b to form a p + layer 146.

Next, as shown in FIG. 6, a first interlayer insulating film 147 made of, for example, SiO _{2 is formed} on the pattern of the gate insulating film 153 and the gate electrode 152 by, eg, CVD.
Further, for example, a mask made of polyimide (not shown) is patterned, and the gate insulating film 153 and the first interlayer insulating film 147 are selectively etched to form the first contact hole 157. The first contact hole 157 penetrates the gate insulating film 153 and the first interlayer insulating film 147 and reaches the semiconductor layer patterns 143b and 143c.
At this time, the base insulating film 142, the gate insulating film 153, and the first interlayer insulating film 147 are selectively removed by etching in a portion where the semiconductor layer patterns 143 b and c and the gate electrode 152 pattern are not formed. Then, the laminated body (142, 153, 147) of the insulating film is made into an island. Using the separation layer 120 as an etching stopper, the separation layer 120 is exposed at the etched portion.

  Next, as shown in FIG. 7A, a partial cross-sectional view, and in FIG. 7B, FIG. 7A as viewed from above, a stack of insulating films formed into islands (142, 153, 147) and a source / drain electrode 158 made of a metal such as aluminum on the isolation layer 120 exposed by etching.

Next, as shown in FIG. 8, a second interlayer insulating film 160 is formed on the source / drain electrodes 158 and the first interlayer insulating film 147. The second interlayer insulating film 160 may be an inorganic insulating film such as SiO ₂ or Si ₃ N _4, but is preferably made of a resin such as acrylic. By using the resin, the second interlayer insulating film 160 can be easily planarized.

By adopting the manufacturing method including the steps as described above, the insulating film other than the portion necessary for fulfilling the function as an electronic device is removed by etching, and the insulating film stack (147, 153, 142) is removed from the island. Therefore, when the thin film device layer is transferred to the flexible substrate or the obtained device is bent, the internal stress can be released and the stress concentration can be reduced. As a result, the occurrence of cracks or the destruction of the drive circuit of the device can be suppressed, and the transfer yield and the reliability after manufacture can be improved.
Further, since the insulating film stack is islanded and separated from each other, even if a crack occurs in one island, it can be prevented from propagating to the surrounding island.

  Next, as shown in FIG. 9, the second interlayer insulating film 160 is etched to form a second contact hole 162 reaching the source / drain electrode 158, and the pixel electrode 161 is patterned. The pixel electrode 161 is formed using an oxide semiconductor such as ITO or a metal such as aluminum.

Next, as shown in FIG. 10A, a primary transfer substrate 163 made of a resin such as glass or acrylic is bonded onto the TFT using a water-soluble adhesive 164, and a laser is applied from the back surface of the substrate 100, for example. Irradiate light. When the laser beam is transmitted through the substrate 100 and irradiated onto the separation layer 120, peeling occurs in the layer or the interface of the separation layer 120, and the thin film device becomes a primary transfer substrate 163 as shown in FIG. Is transcribed.
Preferable examples of the water-soluble adhesive 164 include epoxy-based, acrylate-based, and silicone-based adhesives.

Next, as shown in FIG. 11A, a secondary transfer substrate (flexible substrate) 166 made of, for example, resin is bonded to the surface from which the substrate 100 and the separation layer 120 have been peeled using a water-insoluble adhesive 165. To do.
Next, as shown in FIG. 11B, the entire laminate is immersed in water to peel off the primary transfer substrate 163. Since the primary transfer substrate 163 is bonded by the water-soluble adhesive 164, it can be easily peeled off.

  The resin used for the substrate 100, the primary transfer substrate 163, and the secondary transfer substrate 166 may be either a thermoplastic resin or a thermosetting resin. For example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene- Polyolefin such as vinyl acetate copolymer (EVA), cyclic polyolefin, modified polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polyamideimide, polycarbonate, poly- (4-methylbenten-1), ionomer, Acrylic resin, polymethyl methacrylate, acrylic-styrene copolymer (AS resin), butadiene-styrene copolymer, polio copolymer (EVOH), polyethylene terephthalate (PET), polypropylene terephthalate (PBT), prici Polyester such as rhohexane terephthalate (PCT), polyether, polyetherketone (PEK), polyetheretherketone (PEEK), polyetherimide, polyacetal (POM), polyphenylene oxide, modified polyphenylene oxide, polyarylate, aromatic polyester (Liquid crystal polymer), polytetrafluoroethylene, polyvinylidene fluoride, other fluororesins, styrene, polyolefin, polyvinyl chloride, polyurethane, fluororubber, chlorinated polyethylene, and other thermoplastic elastomers, epoxy resins Phenol resins, urea resins, melamine resins, unsaturated polyesters, silicone resins, polyurethanes, etc., or copolymers, blends, polymer alloys, etc. mainly composed of these. One or (for example as a laminate of two or more layers) or a combination of two or more may be used among al.

  Next, as shown in FIG. 12, a display element layer 170 including microcapsules 242, ITO electrodes 260, and a counter substrate 280 is formed. For example, a display element layer 170 in which an electrophoretic material including a microcapsule 242 is coated on a PET (counter substrate 280) in which a transparent electrode (260) such as ITO is uniformly formed is bonded to a transfer body. To obtain an electrophoretic display device.

  The flexible electronic device of the present invention is a substrate 100, a separation layer 120 formed on the substrate 100, and an insulating film laminate formed in an island shape on the separation layer 120. , An insulating film stack including a pattern of the semiconductor layer 143 and / or the gate electrode 152, an insulating film stack, and an exposed structure, each of which includes a stacked body of the base insulating film 142, the gate insulating film 153, and the first interlayer insulating film 147. A source / drain electrode 158 formed on the isolation layer 120 and a second interlayer insulating layer 160 are included.

  By adopting the manufacturing method or configuration as described above, the insulating film stack (147, 153, 142) is made into an island by removing the insulating film other than the portion necessary for fulfilling the function as an electronic device by etching. Since they are separated from each other, when the obtained device is bent, internal stress can be released and stress concentration can be relaxed. As a result, the occurrence of cracks in bending or the destruction of the drive circuit of the device can be suppressed, and the reliability of the device can be improved. Further, since the insulating film stack is islanded and separated from each other, even if a crack occurs in one island, it can be prevented from propagating to the surrounding island.

  In the above embodiment, the case where the microcapsule is used as the display element layer 170 has been described. However, the present invention is not limited to this, and a liquid crystal, an organic EL material, or the like may be bonded.

  In addition, the primary transfer substrate 163 may be an independent device such as a liquid crystal cell, for example, a thin film transistor, a thin film diode, a ferroelectric thin film element, a color filter, an electrode layer, a dielectric layer, A part of the device may be configured like an insulating layer or a semiconductor element.

  In addition to TFTs, thin film devices include, for example, thin film diodes, photoelectric conversion elements (photosensors, solar cells) and silicon resistance elements composed of silicon PIN junctions, other thin film semiconductor devices, electrodes (eg, ITO, Transparent electrodes such as mesa films), actuators such as switching elements, memories, piezoelectric elements, micromirrors (piezo thin film ceramics), magnetic recording thin film heads, coils, inductors, thin film highly magnetically permeable materials, and micro magnetic devices that combine them A filter, a reflective film, a dichroic mirror, or the like may be used.

FIG. 1 is a partial cross-sectional view showing a polysilicon patterning process in the manufacturing method according to the embodiment. FIG. 2 is a partial cross-sectional view showing an n + ion implantation step in the manufacturing method according to the embodiment. FIG. 3 is a partial cross-sectional view showing a step of forming a gate insulating film in the manufacturing method according to the embodiment. FIG. 4 is a partial cross-sectional view showing gate electrode patterning and N-ion implantation steps in the manufacturing method according to the embodiment. FIG. 5 is a partial cross-sectional view showing a p + ion implantation step in the manufacturing method according to the embodiment. FIG. 6 is a partial cross-sectional view showing the first contact hole patterning and island forming steps in the manufacturing method according to the embodiment. FIG. 7A is a partial cross-sectional view showing the patterning process of the source / drain electrodes in the manufacturing method according to the embodiment, and FIG. 7B is a view seen from above. FIG. 8 is a partial cross-sectional view showing the formation process of the second interlayer insulating film in the manufacturing method according to the embodiment. FIG. 9 is a partial cross-sectional view showing a pixel electrode patterning step in the manufacturing method according to the embodiment. FIG. 10A is a partial cross-sectional view showing a primary transfer substrate bonding and laser light irradiation process in the manufacturing method according to the embodiment, and FIG. 10B is a partial cross-sectional view showing a manufacturing substrate peeling process. . FIG. 11A is a partial cross-sectional view showing a secondary transfer substrate bonding step in the manufacturing method according to the embodiment, and FIG. 11B is a partial cross-sectional view showing a peeling step of the primary transfer substrate. FIG. 12 is a partial cross-sectional view showing a process of forming a display element layer in the manufacturing method according to the embodiment.

Explanation of symbols

100 substrate, 120 separation layer, 142 base insulating film, 143b, c semiconductor layer pattern, 171, 172, 173 mask layer, 144 n + layer, 145 n− layer, 146 p + layer, 153 gate insulating film, 152 gate electrode, 147 First interlayer insulating film, 157 first contact hole, 158 source / drain electrode, 160 second interlayer insulating film, 161 pixel electrode, 164 water-soluble adhesive, 163 primary transfer substrate, 165 water-insoluble adhesive, 166 Secondary transfer substrate, 242 microcapsule, 260 ITO electrode, 280 counter substrate, 170 display element layer

Claims (5)

A method for manufacturing a flexible electronic device, comprising:
Forming a base insulating film on the first substrate;
Forming a semiconductor layer pattern on the base insulating film;
Forming a gate insulating film on the pattern of the base insulating film and the semiconductor layer;
Forming a gate electrode pattern on the gate insulating film;
Forming a first interlayer insulating film on the gate insulating film and the gate electrode pattern;
Removing the base insulating film, the gate insulating film, and the first interlayer insulating film in a portion where the pattern of the semiconductor layer or the gate electrode is not formed, and islanding the insulating film stack;
A method for manufacturing a flexible electronic device.   2. The flexible device according to claim 1, further comprising a step of forming source / drain electrodes on the island-formed insulating film stack and on a portion of the first substrate from which the insulating film stack is removed. Electronic device manufacturing method. The step of forming the base insulating film on the first substrate includes a step of forming a separation layer on the first substrate and a step of forming the base insulating film on the separation layer.
Peeling the base insulating film, the semiconductor layer pattern, the gate insulating film, the gate electrode pattern, and the thin film element layer including the first interlayer insulating film from the first substrate;
The method of manufacturing a flexible electronic device according to claim 1, further comprising: transferring the thin film element layer to a second substrate. A flexible electronic device,
A first substrate having flexibility;
An insulating film laminated body formed in an island shape on the first substrate, comprising a laminated body of a base insulating film, a gate insulating film, and a first interlayer insulating film, and a pattern of a semiconductor layer and / or a gate electrode An insulating film laminate including:
Including flexible electronic devices.   The semiconductor device further includes source / drain electrodes formed on the insulating film stack formed in the island shape and on a portion of the first substrate where the insulating film stack is not formed. 4. The flexible electronic device according to 4.

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