JP6531031B2 - Method of manufacturing substrate - Google Patents

Description

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

  In recent years, manufacture of a substrate having an electronic element mounted and formed on its surface has become popular. In the case of a thin substrate, various methods for supporting the substrate have been proposed for the production thereof.

 In particular, in the manufacture of a flexible organic EL display having a flexible substrate, a thin substrate is fixed on a transfer substrate, and in this state, the process of mounting and forming an electronic element is performed. This manufacturing method includes, for example, the following processes.

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

  The most problematic in the above process is the peeling process. In order to bake the liquid varnish to form a film, the transfer substrate and the varnish surface are fixed. This is inevitable even if an inorganic film as a sacrificial film is inserted as an intermediate film. Therefore, after completion of the panel, laser irradiation is required from the back surface of the transfer substrate to peel the film from the transfer substrate. The laser irradiation equipment not only requires excessive equipment investment, but also the problem of damage and yield reduction due to the laser irradiation is a major problem, which is the biggest obstacle to the spread of the flexible organic EL display.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a method of manufacturing a substrate with reduced damage and reduced yield at low cost.

  According to the present invention, there is provided a method of manufacturing a substrate, comprising: an inorganic material for forming an inorganic material layer on a surface to be joined to the substrate, in the substrate for conveyance for conveying the substrate having the electronic element formed on the surface. A layer forming step, a coating step of applying a varnish on the inorganic material layer, a baking step of forming the varnish into a film, and a peeling step of peeling the film-shaped substrate and the transport substrate A method of manufacturing a substrate is provided.

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

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

  According to one aspect of the present invention, the method for manufacturing a substrate described above further includes an ultraviolet light irradiation step of irradiating ultraviolet light onto the varnish which has been fired and becomes a film before the peeling step.

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

  According to one aspect of the present invention, in the method of manufacturing a substrate described above, ultraviolet light having a wavelength of 240 to 270 nm is irradiated in the ultraviolet light irradiation step.

  According to one aspect of the present invention, in the method of manufacturing a substrate described above, before the step of forming the inorganic material layer, the surface activation treatment step of performing surface activation treatment on the surface of the transfer substrate on which the inorganic material layer is formed Further equipped.

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

  According to one aspect of the present invention, in the method for manufacturing a substrate described above, the thickness of the inorganic material layer formed on the transfer substrate is 100 nm or less.

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

 According to the present invention, it is possible to provide a method of manufacturing a substrate with low damage and reduced yield and reduced yield.

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  The present invention will be described below by way of 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 of manufacturing a substrate, the substrate for transfer for transferring a film substrate having an electronic element formed on the surface, wherein an inorganic material layer is formed on a surface to be bonded to the substrate. A material layer forming step, a coating step of applying a varnish on the inorganic material layer, a baking step for forming the varnish into a film shape, and a peeling step of peeling the substrate in a film shape and the carrier substrate There is provided a method of manufacturing a substrate comprising the method.

  The transport substrate is for transporting a substrate having an electronic element formed on the surface, and may be made of a plate-like or film-like glass, a heat resistant film, a wafer or a composite material of these. The transfer substrate may be provided in the form of a sheet or a roll. The transport substrate preferably has a thickness of 0.1 mm or more and 1.1 mm or less from the viewpoint of being able to use existing equipment.

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

(Inorganic material layer formation process)
The method for manufacturing a substrate according to the present embodiment includes an inorganic material layer forming step of forming an inorganic material layer on the surface to be joined with the substrate in the transfer substrate.
The inorganic material is required to contain no or extremely low oxygen content and moisture inside the material. The flatness after formation of the inorganic material is preferably Ra 50 nm or less.

The inorganic material layer is mainly formed 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) or platinum (Pt) And metals such as transition metals, solder alloys containing tin (Sn) and silver (Ag) or alloys thereof, semiconductors such as silicon (Si), silicon oxides (SiO ₂ ), silicon nitrides (SiN x), silicon oxynitrides (SiN x O y), aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), titanium nitride (TiN), silicon carbide (SiC), nitrides such as titanium carbide (TiC), nitride oxides, oxides or carbides It 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 forming an inorganic material layer by depositing a predetermined inorganic material by plasma-enhanced chemical vapor deposition (PECVD) or sputter deposition, the inorganic material other than the predetermined inorganic material may be used. It may be mixed. For example, when a sputtering target is irradiated with a particle beam and a predetermined inorganic material of the sputtering target is released from the sputtering target and sputter deposition is performed, an inorganic material other than the predetermined inorganic material is added to the path of the particle beam. Target may be placed. Thus, it is possible to sputter deposit a mixed inorganic material in which an inorganic material other than the predetermined inorganic material is mixed with the predetermined inorganic material. For example, the predetermined inorganic material may be silicon (Si), and an 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 the film quality of the inorganic material layer be adjusted in a state of being easily peeled off after passing through the heating step, the cleaning step and the like.

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

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

(Coating process)
The method of manufacturing a substrate according to the present embodiment includes an applying step of applying a varnish on the inorganic material layer.

The varnish is preferably a polymer having heat resistance. Specifically, a polyimide resin is preferable as the varnish.
Although the coating method of a varnish is not specifically limited, It is preferable that it is a slit coater. The varnish is preferably applied as a polyamic acid solution which is a precursor of polyimide. Further, it may be an imidized polyimide solution. The varnish is applied to a substrate and baked at a high temperature to remove the solvent, and the imidization reaction proceeds to form a polyimide film which is insoluble and infusible and which is excellent in heat resistance, chemical resistance and electrical insulation.

  The application of the varnish is more preferably performed in the air atmosphere within 24 hours after the formation of the inorganic film. More preferably, the varnish is applied in the air atmosphere within 12 hours after formation of the inorganic film.

  In the method of manufacturing a substrate according to the present embodiment, the varnish coating environment is preferably performed in an atmosphere substituted with nitrogen gas.

(Firing process)
The method for manufacturing a substrate according to the present embodiment includes a firing step for forming the varnish applied to the transfer substrate into a film shape. The film is fixed to the carrier substrate by firing.

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

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

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

(Multiple inorganic material layer formation process)

The method of manufacturing a substrate 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 subjected to the surface treatment after the surface treatment step. In this case, the inorganic material layer is preferably composed of a material different from that of the adjacent layer as a second inorganic material layer and a 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, peeling preferably occurs between these inorganic material layers. Moreover, it is also possible to make it easy to produce exfoliation between layers, when each inorganic material has a different amount of oxygen and moisture, respectively.

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

 In the method of manufacturing a substrate according to the present embodiment, it is more preferable to irradiate ultraviolet light with a wavelength of 350 to 380 nm in the ultraviolet light irradiation step. Or it is more preferable to irradiate the ultraviolet-ray of wavelength 240-270 nm.

(Surface activation process)
The method of manufacturing a substrate according to the present embodiment may further include a surface activation treatment step of performing surface activation treatment on the surface of the transfer substrate on which the inorganic material layer is formed, before the inorganic material layer forming step.
The surface activation treatment step may be a surface activation step which is activated by irradiating particles having a predetermined kinetic energy. The surface layer such as oxide or contaminant is removed by causing particles having a predetermined kinetic energy to collide and causing a substance (sputtering phenomenon) to physically flick off the substance forming the bonding surface, thereby removing surface energy The emerging surface of the 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 less likely to cause a chemical reaction with a substance that forms a bonding surface to be collided, and thus do not significantly change the chemical properties of the bonding surface by forming a compound or the like.
The particles to be collided with the surface to be activated can be given predetermined kinetic energy by accelerating the particles toward the bonding surface using a particle beam source or a plasma generator.

  The kinetic energy of the particles to be bombarded on the surface to be activated is preferably 1 eV to 2 keV. It is thought that the above-mentioned kinetic energy efficiently causes sputtering in the surface layer. Depending on the thickness of the surface layer to be removed, the property of the material and the like, the material of the new surface, and the like, the value of the desired kinetic energy can be set from the above range of kinetic energy.

The particle beam source can also be used to provide particles with a predetermined kinetic energy. The particle beam source operates in a relatively high vacuum, for example at a background pressure of 1 × 10 ⁻⁸ Pa (pascal) or less. Substances removed from the surface of the metal area are efficiently exhausted out of the atmosphere by the operation of the vacuum pump to draw a relatively high vacuum. This can inhibit the adhesion of undesired substances to the exposed nascent surface. Furthermore, the particle beam source can apply a relatively high acceleration voltage so that high kinetic energy can be applied to the particles. Therefore, it is considered that removal of the surface layer and activation of the new surface can be performed efficiently.
Alternatively, the surface activation treatment may be performed in a vacuum or reduced pressure atmosphere where the background pressure is 1 × 10 ⁻⁸ Pa or more and less than the atmospheric pressure.

As a particle beam source, an ion beam source emitting an ion beam or a neutral atom beam source emitting a neutral atom beam can be used. A cold cathode ion source can be used as the ion beam source.
As a neutral atom beam source, a fast atom beam source (FAB, Fast Atom Beam) can be used. A fast atom beam source (FAB) typically generates a plasma and applies an electric field to the plasma to extract positive ions of ionized particles from the plasma and pass them through an electron cloud for neutralization. Have. In this case, for example, in the case of argon (Ar) as a 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 It may be set to a value between and 500 W (watts). For example, when the fast atom beam source (FAB) is operated at 100 W (watt) to 200 W (watt) and the high speed atom beam of argon (Ar) is irradiated for about 2 minutes, the oxides, contaminants, etc. The layer can be removed to expose the nascent surface.

In the present invention, particles used for surface activation may be neutral atoms or ions, may be radical species, or 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 may vary. Therefore, it is necessary to adjust the treatment time required for the surface activation treatment. For example, the presence of oxygen or carbon contained in the surface layer is confirmed by using surface analysis such as Auger Electron Spectroscopy (AES) or X-ray Photo Electron Spectroscopy (XPS). A time that can not be used or a longer time may be adopted as a processing time of the surface activation process.

  The particles can also be provided with a predetermined kinetic energy 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 cations of ionized particles in the plasma are accelerated toward the bonding surface by the voltage. Give the desired kinetic energy. Since plasma can be generated in an atmosphere with a low degree of vacuum of several Pascals (Pa), the vacuum system can be simplified, and processes such as vacuum drawing can be shortened.

  Conventionally, the transport substrate used once was disposable, but according to the manufacturing method of the above embodiment, the substrate such as laser irradiation is not damaged, and no organic adhesive is 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 transfer substrate by the ion beam.

  As mentioned above, although embodiment of this invention was described, it is obvious that combining each structure of these embodiment is also contained in this invention.

  Below, the Example of this invention is shown.

  In the following examples, a film formation process of an inorganic material layer was performed on a glass substrate by a room temperature bonding apparatus, and a varnish was applied on the substrate. After firing the varnish, a peeling test was carried out to verify the peeling strength under the conditions of film formation and the like. As a personal observation procedure, it was roughly "a glass substrate film-forming process-> varnish application-> temporary baking-> main baking-> peeling test. The conditions of the test are as follows.

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

(Application of varnish)
Varnish: Ube Industries, Ltd. (U-Vanish-S)
Slit coater: Tokyo Electron Ltd. Coating conditions: Coating pressure aiming 10 μm
Coating range 90mm x 70mm

(Peeling film deposition)
Cold bonding apparatus: Run technical service Co., Ltd. Test conditions: A test was made using two samples of each of the conditions described in [Table 2], using the L18 direct chart of [Table 1]. B: The number of times of film formation of the type of intermediate film SiO ₂ was 10 scans. A film of about 1.5 nm to 2 nm is formed in one scan.

(Temporary baking)
Hot plate: Asone Corporation EHP-250N
Residual heat: 90 ° C 5 minutes main firing 90 ° C 10 minutes

(Full firing and additional firing)
Firing furnace: Made by Denken KDF-900GL
Firing conditions: Temperature program recommended by varnish manufacturer (The heating time is set based on 10 minutes / 50 ° C)

(Peeling strength test)
Composite material testing machine: Instron Co., Ltd. 5865
Peeling speed: 300 mm / min
Peeling size: 60 mm (width)
Peeling test method:
-Peel off about 5 mm of one side of the varnish after firing and stick it 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 pasted with Kapton tape with the upper chuck.
-Peeling is performed at a peeling speed of 300 mm / min, and peeling is completed in a completely peeled state.

(UV irradiation)
UV irradiator: Run Technical Service Co., Ltd. ODF bonding apparatus UV irradiation condition:
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 1 minute after lighting. The UV lamp used a metal halide lamp, and the wavelength was changed by a cut filter. By adjusting the irradiation time, the total heat of irradiation was made equal.

  The results of each test are shown in FIG. 2 to FIG. Further, FIG. 22 shows a list of test results. The relationship between each factor shown in Table 1 and the bonding strength is considered to be related as shown in FIG.

Claims (11)

A method of manufacturing a substrate,
In conveying the substrate for conveying the substrate having the electronic element is formed on the surface, the planned bonding surfaces of the substrate, and an inorganic material layer forming step of forming an inorganic material layer,
A surface treatment step of subjecting the inorganic material layer to a surface treatment under a rare gas or an inert gas after the inorganic material layer forming step;
Applying a varnish on the inorganic material layer;
A baking process for forming the film into a varnish,
And a peeling step of peeling the film-like substrate and the transfer substrate from each other .
The material of the said inorganic material layer is a silicon | silicone, The manufacturing method of the board | substrate characterized by the above-mentioned .   The method for producing a substrate according to claim 1, wherein the varnish application environment is performed in an atmosphere substituted with nitrogen gas. The method for producing a substrate according to claim 1 or 2 , further comprising an ultraviolet irradiation step of irradiating ultraviolet light onto the varnish which has been fired to form a film before the peeling step. The method for producing a substrate according to claim 3 , wherein ultraviolet light having a wavelength of 350 to 380 nm is irradiated in the ultraviolet irradiation step. The method for producing a substrate according to claim 3 , wherein ultraviolet light having a wavelength of 240 to 270 nm is irradiated in the ultraviolet irradiation step. The method according to any one of claims 1 to 5 , further comprising a surface activation treatment step of subjecting the surface of the transfer substrate on which the inorganic material layer is to be formed to a surface activation treatment prior to the inorganic material layer formation step. The manufacturing method of the board | substrate as described in. The method for producing a substrate according to any one of claims 1 to 6 , wherein the varnish application environment is performed under a nitrogen environment . The method according to any one of claims 1 to 7 , wherein the thickness of the inorganic material layer formed on the transfer substrate is 100 nm or less. The method for producing a substrate according to any one of claims 1 to 8 , wherein the environment for forming the inorganic material layer is a pressure of 10 ^-8 pa or less. A method of manufacturing a substrate,
An inorganic material layer forming step of forming a layer made of copper on a surface to be joined to the substrate, in a substrate for transfer for transferring a substrate having an electronic element formed on the surface;
A surface activation treatment step of subjecting the surface of the transfer substrate on which the inorganic material layer is to be formed to a surface activation treatment prior to the inorganic material layer formation step;
A surface treatment step of subjecting the inorganic material layer to a surface treatment after the inorganic material layer formation step;
Applying a varnish on the inorganic material layer;
A baking process for forming the film into a varnish,
An ultraviolet irradiation step of irradiating ultraviolet rays to the varnish which has been fired and becomes a film;
And a peeling step of peeling the film-like substrate from the substrate for transfer,
A method of manufacturing a substrate, wherein the coating step is performed under a nitrogen environment. A method of manufacturing a substrate,
An inorganic material layer forming step of forming a layer made of silicon on a surface to be joined to the substrate, in a substrate for transfer for transferring a substrate having an electronic element formed on the surface;
A surface treatment step of subjecting the inorganic material layer to a surface treatment;
After the surface treatment step, SiO on the inorganic material layer subjected to the surface treatment is further added. ₂ Forming a second inorganic material layer comprising
Applying a varnish on the second inorganic material layer;
A baking process for forming the film into a varnish,
And a peeling step of peeling the film-like substrate from the substrate for transfer,
A method for producing a substrate, further comprising at least one step selected from the group consisting of the following (1) to (3).
(1) A surface activation treatment step of subjecting the surface of the transport substrate on which the inorganic material layer is to be formed to a surface activation treatment before the inorganic material layer formation step.
(2) A surface treatment step of subjecting the second inorganic material layer to a surface treatment under a rare gas or an inert gas.
(3) an ultraviolet irradiation step of irradiating ultraviolet rays to the varnish which has been fired to be in the form of a film.