JP2017088735A - Substrate manufacturing method - Google Patents

Abstract

【Task】
An object of the present invention is to provide a method for manufacturing a substrate that is low in cost and suppresses damage and yield reduction.
[Solution]
A method for manufacturing a substrate, comprising: an inorganic material layer forming step for forming an inorganic material layer on a surface to be bonded to a substrate for transporting a substrate on which an electronic element is formed; A substrate comprising: a coating step for applying a varnish on a material layer; a baking step for forming the varnish into a film; and a peeling step for peeling the substrate in a film form from the substrate for conveyance. A manufacturing method is provided.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a substrate on which an electronic element is mounted.

  In recent years, the manufacture of substrates on which electronic elements are mounted and formed on the surface has become active. In manufacturing the thin substrate, various methods for supporting the substrate have been proposed.

 In particular, in the manufacture of a flexible organic EL display that gives flexibility to a substrate, a thin substrate is fixed on a carrier substrate, and an electronic element mounting / forming process (process) is performed in that state. This manufacturing method includes, for example, the following processes.

1) Coating a transfer polyimide substrate with liquid polyimide (varnish).
2) After that, it is baked at a temperature of 300 ° C. to 500 ° C. for several hours to prepare a polyimide film.
3) Since polyimide is a film that easily permeates moisture, there may be a step of forming a multilayered inorganic / organic thin film thereon and adding a function of blocking moisture.
4) Finally, in order to peel the polyimide film from the transport glass substrate, laser irradiation is performed from the back surface of the transport glass substrate. Moreover, in order to peel off a film and glass efficiently by this laser irradiation, an inorganic film | membrane may be vapor-deposited beforehand. In this case, this inorganic film is called a sacrificial film and reacts with a laser, and there are cases where it is aimed to accelerate peeling by reacting oxygen, moisture, etc. inside the inorganic film. However, such an inorganic film itself does not have a peeling effect.

  The most problematic of the above processes is the peeling process. Since the liquid varnish is baked to form a film, the carrier substrate and the varnish surface are fixed. This is unavoidable even if an inorganic film as a sacrificial film is inserted as an interlayer. For this reason, after the panel is completed, laser irradiation is required from the back surface of the transport substrate to peel the film from the transport substrate. This laser irradiation equipment not only requires an excessive capital investment, but also a problem of damage and a decrease in yield due to laser irradiation is a major problem, which is the biggest obstacle to the spread of flexible organic EL displays.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a substrate that is low cost and suppresses damage and yield reduction.

  According to the present invention, there is provided a method for manufacturing a substrate, which is a transport substrate for transporting a substrate on which an electronic element is formed, and an inorganic material that forms an inorganic material layer on a surface to be bonded to the substrate. A layer forming step, a coating step for applying a varnish on the inorganic material layer, a firing step for forming the varnish into a film, and a peeling step for peeling the substrate in a film form from the substrate for conveyance. A method for manufacturing a substrate is provided.

  According to one aspect of the present invention, the above-described substrate manufacturing method further includes a surface treatment step of performing a surface treatment on the inorganic material layer after the inorganic material layer forming step.

  According to one aspect of the present invention, in the above-described substrate manufacturing method, the varnish application environment is an atmosphere substituted with nitrogen gas.

  According to one aspect of the present invention, the substrate manufacturing method further includes an ultraviolet irradiation step of irradiating the varnish that has been baked and formed into a film before the peeling step.

  According to one embodiment of the present invention, in the above-described substrate manufacturing method, ultraviolet light having a wavelength of 350 to 380 nm is irradiated in the ultraviolet irradiation step.

  According to one embodiment of the present invention, in the above-described substrate manufacturing method, ultraviolet rays having a wavelength of 240 to 270 nm are irradiated in the ultraviolet irradiation step.

  According to one aspect of the present invention, in the above-described substrate manufacturing method, the surface activation treatment step of performing the surface activation treatment on the surface of the transport substrate on which the inorganic material layer is formed is performed before the inorganic material layer formation step. Further prepare.

  According to one aspect of the present invention, in the substrate manufacturing method described above, the varnish application environment is performed in a nitrogen environment.

  According to one embodiment of the present invention, in the substrate manufacturing method, the thickness of the inorganic material layer formed on the transport substrate is 100 nm or less.

According to one embodiment of the present invention, in the substrate manufacturing method described above, the environment for forming the inorganic material layer is a pressure of 10 ⁻⁸ pa or less.

 ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the board | substrate which suppressed damage and the yield fall at low cost is provided.

It is a figure explaining the outline of a peeling tester. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows substrate processing conditions and baking and peeling conditions. It is a figure which shows the list of a test result. It is a figure which compares a factor and a test result.

  Hereinafter, the present invention will be described with reference to embodiments, but it is obvious that the present invention is not limited to these specific embodiments.

[Embodiment 1]
According to the present invention, there is provided a method for manufacturing a substrate, which is a transport substrate for transporting a film substrate on which an electronic element is formed, wherein an inorganic material layer is formed on a surface to be bonded to the substrate. A material layer forming step, a coating step for applying a varnish on the inorganic material layer, a firing step for forming the varnish into a film, and a peeling step for peeling the film-formed substrate from the transport substrate. A method for manufacturing a substrate is provided.

  The carrying substrate is for carrying a substrate on which an electronic element is formed, and may be composed of plate-like or film-like glass, a heat-resistant film, a wafer, or a composite material thereof. The conveyance substrate may be provided in a form wound in a sheet shape or a roll shape. The thickness of the transport substrate is preferably 0.1 mm or greater and 1.1 mm or less from the viewpoint that existing facilities can be used.

  Examples of the electronic element formed on the substrate include a TFT and an organic EL element, but are not limited thereto. When the electronic element is, for example, a TFT (thin film transistor), there is a heating step of about 300 ° C. to 500 ° C. in the formation process or the like.

(Inorganic material layer forming process)
The substrate manufacturing method according to the present embodiment includes an inorganic material layer forming step of forming an inorganic material layer on a surface to be bonded to the substrate in the transfer substrate.
This inorganic material is required to contain no or very little oxygen or moisture inside the material. Further, the flatness after the formation of the inorganic material is preferably Ra 50 nm or less.

The inorganic material layer is formed mainly of an inorganic material selected from the group consisting of metals, semiconductors, nitrides, nitride oxides, oxides and carbides. As the inorganic material layer, aluminum (Al), nickel (Ni), copper (Cu), iron (Fe), titanium (Ti), tantalum (Ta), chromium (Cr), gold (Au) and platinum (Pt) Metals including transition metals such as, solder alloys including tin (Sn), silver (Ag) or alloys thereof, semiconductors such as silicon (Si), silicon oxide (SiO ₂ ), silicon nitride (SiNx), silicon oxynitride (SiNxOy), aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), titanium nitride (TiN) and other silicon carbide (SiC), titanium carbide (TiC) and other nitrides, nitride oxides, oxides or carbides Can be adopted. In particular, silicon is preferable as the inorganic material layer. .

  The inorganic material layer is preferably formed by a deposition method such as plasma enhanced chemical vapor deposition (PECVD) or sputter deposition, but is not limited thereto. In addition, when an inorganic material layer is formed by depositing a predetermined inorganic material by plasma-enhanced chemical vapor deposition (PECVD) or sputtering deposition, an inorganic material other than the predetermined inorganic material is used. You may mix. For example, when sputter deposition is performed by irradiating a sputter target with a particle beam to release a predetermined inorganic material of the sputter target from the sputter target, an inorganic material other than the predetermined inorganic material is introduced into the path of the particle beam. A target may be placed. Thereby, the mixed inorganic material in which an inorganic material other than the predetermined inorganic material is mixed with the predetermined inorganic material can be sputter-deposited. For example, the predetermined inorganic material may be silicon (Si), and the inorganic material other than the predetermined inorganic material may be a transition metal such as iron (Fe).

  Further, it is more preferable that the film thickness and film quality of the inorganic material layer be adjusted so that the inorganic material layer can be easily peeled off after undergoing a heating process, a washing process, and the like.

  In the substrate manufacturing method according to this embodiment, the thickness of the inorganic material layer formed on the transport substrate is preferably 100 nm or less, and more preferably 10 nm or less. By setting the thickness of the inorganic material layer within this range, the surface roughness of the inorganic material layer is suppressed, and the bonding strength with the varnish becomes appropriate.

In the substrate manufacturing method according to the present embodiment, the inorganic material layer forming environment is preferably a pressure of 10 ⁻⁸ pa or less.

(Coating process)
In the manufacturing method of the board | substrate which concerns on this embodiment, the application | coating process which apply | coats a varnish on an inorganic material layer is included.

The varnish is preferably a polymer having heat resistance. Specifically, a polyimide resin is preferable as the varnish.
The method for applying the varnish is not particularly limited, but is preferably a slit coater. The varnish is preferably applied as a polyamic acid solution which is a polyimide precursor. Further, it may be an imidized polyimide solution. By applying this varnish to a substrate and baking it at a high temperature, the solvent is removed and the imidization reaction proceeds, resulting in an insoluble and infusible polyimide film with excellent heat resistance, chemical resistance, and electrical insulation.

  More preferably, the varnish is applied in an air atmosphere within 24 hours after the formation of the inorganic film. More preferably, the varnish is applied in an air atmosphere within 12 hours after the inorganic film is formed.

  In the substrate manufacturing method according to the present embodiment, it is preferable that the varnish application environment is an atmosphere substituted with nitrogen gas.

(Baking process)
In the manufacturing method of the board | substrate concerning this embodiment, the baking process for making the varnish apply | coated to the conveyance board | substrate into a film form is included. The film is fixed to the transport substrate by baking.

(Peeling process)
The substrate manufacturing method according to the present embodiment includes a peeling step of peeling the substrate and the transfer substrate.

(Surface treatment process)
In the substrate manufacturing method according to the present embodiment, it is more preferable to further include a surface treatment step of performing a surface treatment on the inorganic material layer after the inorganic material layer forming step.

In the substrate manufacturing method according to this embodiment, the surface treatment step is more preferably performed by sputtering of a rare gas or an inert gas. Specifically, it is more preferable that the sputtering is performed with neon (Ne), argon (Ar), and N ₂ gas.

(Multiple inorganic material layer forming process)

The substrate manufacturing method according to the present embodiment may further include an inorganic material layer forming step of forming an inorganic material layer on the inorganic material layer that has been subjected to the surface treatment after the surface treatment step. In this case, the inorganic material layer is preferably made of a material different from the adjacent layers as the second inorganic material layer and the third inorganic material layer. For example, it is more preferable that the inorganic material layer is Si and the second inorganic material layer is SiO ₂ . In the case where a plurality of inorganic material layers are formed, more preferably peeling occurs between these inorganic material layers. Further, since each inorganic material has a different amount of oxygen and moisture, it is possible to easily cause peeling between layers.

(UV irradiation process)
In the substrate manufacturing method according to the present embodiment, it is more preferable to further include an ultraviolet irradiation process for irradiating the varnish with ultraviolet light before the peeling process.

 In the substrate manufacturing method according to the present embodiment, it is more preferable to irradiate ultraviolet rays having a wavelength of 350 to 380 nm in the ultraviolet irradiation step. Alternatively, it is more preferable to irradiate ultraviolet rays having a wavelength of 240 to 270 nm.

(Surface activation treatment process)
The substrate manufacturing method according to the present embodiment may further include a surface activation treatment step of performing a surface activation treatment on the surface of the transport substrate on which the inorganic material layer is formed before the inorganic material layer formation step.
The surface activation process may be a surface activation process that is activated by irradiating particles having predetermined kinetic energy. By causing particles having a predetermined kinetic energy to collide and causing the material that forms the bonding surface to physically repel (sputtering phenomenon), the surface layer such as oxides and contaminants is removed, and the surface energy An emerging surface of high or active inorganic material can be exposed.

As particles used for the surface activation treatment, for example, a rare gas or an inert gas such as neon (Ne), argon (Ar), krypton (Kr), or xenon (Xe) can be employed. These rare gases are unlikely to cause a chemical reaction with a substance that forms a collision surface to be collided, so that a chemical property of the bonding surface is not greatly changed by forming a compound or the like.
Particles that collide with the surface to be surface activated can be given a predetermined kinetic energy by accelerating the particles toward the surface using a particle beam source or a plasma generator.

  It is preferable that the kinetic energy of the particles colliding with the surface to be surface activated is 1 eV to 2 keV. It is considered that the above kinetic energy efficiently causes a sputtering phenomenon in the surface layer. A desired value of kinetic energy can also be set from the above kinetic energy range according to the thickness of the surface layer to be removed, the properties such as the material, the material of the new surface, and the like.

A particle beam source can also be used to impart a predetermined kinetic energy to the particles. The particle beam source operates in a relatively high vacuum, such as a background pressure of 1 × 10 ⁻⁸ Pa (pascal) or less. The substance removed from the surface of the metal region is efficiently exhausted out of the atmosphere by the operation of the vacuum pump to draw a relatively high vacuum. Thereby, adhesion of the undesirable substance to the exposed new surface can be suppressed. Furthermore, since the particle beam source can apply a relatively high acceleration voltage, high kinetic energy can be imparted to the particles. Therefore, it is considered that the surface layer can be efficiently removed and the nascent surface can be activated.
Alternatively, the surface activation treatment may be performed in a vacuum or reduced pressure atmosphere in which the background pressure is 1 × 10 ⁻⁸ Pa or more and less than atmospheric pressure.

As the particle beam source, an ion beam source that emits an ion beam or a neutral atom beam source that emits a neutral atom beam can be used. As the ion beam source, a cold cathode ion source can be used.
As the neutral atom beam source, a fast atom beam source (FAB, Fast Atom Beam) can be used. A fast atomic beam source (FAB) typically generates a plasma, applies an electric field to the plasma, extracts particles cations ionized from the plasma, passes them through an electron cloud, and neutralizes them. Have. In this case, for example, when argon (Ar) is used as the rare gas, the power supplied to the fast atom beam source (FAB) may be set to 1.5 kV (kilovolt), 15 mA (milliampere), or 0.1 To a value between 500 W (watts). For example, when a fast atom beam source (FAB) is operated at 100 W (watts) to 200 W (watts) and irradiated with a fast atom beam of argon (Ar) for about 2 minutes, the oxide, contaminants, etc. (surface) Layer) can be removed to expose the nascent surface.

In the present invention, the particles used for surface activation may be neutral atoms or ions, may be radical species, and may be a particle group in which these are mixed.
Depending on the operating conditions of each plasma or beam source, or the kinetic energy of the particles, the removal rate of the surface layer can vary. Therefore, it is necessary to adjust the treatment time required for the surface activation treatment. For example, the presence of oxygen and carbon contained in the surface layer is confirmed using surface analysis methods such as Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS). You may employ | adopt the time which becomes impossible or longer than it as a processing time of a surface activation process.

  A predetermined kinetic energy can also be given to particles using a plasma generator. By applying an alternating voltage to the bonding surface of the substrate, a plasma containing particles is generated around the bonding surface, and the cations of the ionized particles in the plasma are accelerated toward the bonding surface by the voltage. Thus, given kinetic energy is given. Since the plasma can be generated in an atmosphere with a low degree of vacuum of about several pascals (Pa), the vacuum system can be simplified and the steps such as evacuation can be shortened.

  Conventionally, the transport substrate once used was disposable, but according to the manufacturing method of the above embodiment, the substrate such as laser irradiation is not damaged and the organic adhesive is not used. There is also an advantage that the transfer substrate can be reused.

  Further, the inorganic material layer formed by sputtering has an advantage that it can be easily removed from the carrier substrate by an ion beam.

  Although the embodiments of the present invention have been described above, it is obvious that the present invention includes combinations of the configurations of these embodiments.

  Examples of the present invention are shown below.

  In the following examples, an inorganic material layer was formed on a glass substrate by a room temperature bonding apparatus, and varnish was applied on the substrate. After firing the varnish, a peel test was conducted to verify the peel strength according to the film forming conditions. In my opinion, the general procedure is “glass substrate film formation → varnish application → temporary firing → main firing → peeling test”. The test conditions are as follows.

Glass substrate: non-alkali glass (100 × 100) OA-10G

(Varnish application)
Varnish: Ube Industries, Ltd. (U-Vanish-S)
Slit coater: Tokyo Electron Co., Ltd. Application conditions: Aim for application pressure 10 μm
Application range 90mm x 70mm

(Peeling film formation)
Room temperature bonding apparatus: manufactured by Run Technical Service Co., Ltd. Test conditions: The test used L18 direct table of [Table 1], and two samples were manufactured under each condition described in [Table 2]. B: The number of deposition of SiO ₂ of the intermediate film type was 10 scan. A film of about 1.5 nm to 2 nm is formed at 1 scan.

(Temporary firing)
Hot plate: EHP-250N manufactured by ASONE CORPORATION
Residual heat: 90 ° C 5 minutes Main firing 90 ° C 10 minutes

(Main firing and additional firing)
Firing furnace: KDF-900GL manufactured by Denken Co., Ltd.
Firing conditions: According to the temperature program recommended by the varnish manufacturer (heating time is set based on 10 minutes / 50 ° C)

(Peel strength test)
Composite material testing machine: 5865 manufactured by Instron Corporation
Peeling speed: 300mm / min
Peeling size: 60mm (width)
Peel test method:
-One side of the varnish after baking is peeled off by about 5 mm and attached to a glass substrate with Kapton tape.
・ Fix the varnish coated substrate with the lower chuck, and fix the opposite side of the glass substrate bonded with Kapton tape with the upper chuck.
-Peeling is performed at a peeling speed of 300 mm / min, and the peeling is finished in a state where the peeling is completed.

(UV irradiation)
UV irradiation device: Run Technical Service Co., Ltd. ODF bonding apparatus UV irradiation conditions:
Wavelength 1 (254 nm) 23.5 mW / cm ² 20 minutes 28,200 mJ / cm ²
Wavelength 2 (365 nm) 48.0 mW / cm ² 10 minutes 28,200 mJ / cm ²
The illuminance was measured at the center of the lower stage quartz. Illuminance measurement in 1 minute after lighting. As the UV lamp, a metal halide lamp was used, and the wavelength was changed by a cut filter. By adjusting the irradiation time, the total irradiation heat amount was made equal.

  2 to 21 show the results of each test. FIG. 22 shows a list of test results. The relationship between each factor shown in Table 1 and the bonding strength is considered to have the relationship shown in FIG.

Claims (10)

A method for manufacturing a substrate, comprising:
An inorganic material layer forming step of forming an inorganic material layer on a surface to be bonded to the substrate in a transport substrate for transporting a substrate on which an electronic element is formed on the surface;
An application process of applying varnish on the inorganic material layer;
A baking step for making the varnish into a film,
A method for producing a substrate, comprising: a peeling step of peeling the substrate in film form from the substrate for conveyance.   The substrate manufacturing method according to claim 1, further comprising a surface treatment step of performing a surface treatment on the inorganic material layer after the inorganic material layer forming step.  The manufacturing method of the board | substrate of Claim 1 or 2 made | formed in the atmosphere where the application | coating environment of varnish was substituted by nitrogen gas.   The method for producing a substrate according to any one of claims 1 to 3, further comprising an ultraviolet irradiation step of irradiating ultraviolet rays onto the varnish that has been baked and formed into a film before the peeling step.   The method for producing a substrate according to claim 4, wherein in the ultraviolet irradiation step, ultraviolet rays having a wavelength of 350 to 380 nm are irradiated.   The method for producing a substrate according to claim 4, wherein in the ultraviolet irradiation step, ultraviolet rays having a wavelength of 240 to 270 nm are irradiated.   7. The method according to claim 1, further comprising a surface activation treatment step of performing a surface activation treatment on a surface of the transport substrate on which the inorganic material layer is formed before the inorganic material layer formation step. The manufacturing method of the board | substrate of description.   The method for producing a substrate according to any one of claims 1 to 7, wherein the varnish is applied in a nitrogen environment.   The method for manufacturing a substrate according to claim 1, wherein the inorganic material layer formed on the transport substrate has a thickness of 100 nm or less. The method for manufacturing a substrate according to any one of claims 1 to 9, wherein the environment for forming the inorganic material layer is a pressure of 10 ^-8 pa or less.