JP6766428B2 - Method of manufacturing a laminate - Google Patents

Description

The present invention is a laminate composed of a polyimide film and a substrate made of an inorganic substance and a method for manufacturing the same. More specifically, a device made of a thin film such as a semiconductor element, a MEMS element, and a display element and requiring fine processing. To obtain a laminate used for manufacturing a flexible device that is peeled off after the device is formed by temporarily forming the polyimide film on a substrate made of an inorganic substance as a support when forming the polyimide film on the surface. It is an invention concerning the manufacturing method of.
In particular, a thin film such as polyimide, which has excellent heat resistance and insulation properties, and a glass plate, a ceramic plate, a silicon wafer, and a substrate made of a kind of inorganic substance selected from metals, which have a coefficient of linear expansion almost equal to that, are included. It is an invention relating to a laminate having excellent dimensional stability, heat resistance and insulation, and a manufacturing method for obtaining the laminate, to which a laminated precise circuit can be mounted.

In recent years, technological development for forming these elements on a polymer film has been actively carried out for the purpose of reducing the weight and increasing the flexibility of functional elements such as semiconductor elements, MEMS elements, and display elements.
When forming functional elements such as semiconductor elements, MEMS elements, and display elements on the surface of polymer films, it is ideal to process them by a so-called roll-to-roll process that utilizes the flexibility that is a characteristic of polymer films. It is said that. However, in the semiconductor industry, the MEMS industry, and the display industry, process technologies for wafer-based or glass substrate-based rigid flat substrates have been constructed. A realistic choice is to attach a polymer film to a rigid support substrate made of inorganic materials such as metal plates, wafers, and glass substrates, form the desired element, and then peel it off from the support substrate to remove the existing infrastructure. It is possible to obtain a functional element formed on a polymer film by utilizing it.
When bonding a polymer film and a support substrate made of an inorganic substance, the surface smoothness, cleanliness, resistance to process temperature, and chemical solution used for microfabrication are at a level that does not hinder the formation of such functional elements. Tolerance is required. In particular, when the formation temperature of the functional element is high, not only the heat resistance of the polymer film but also the joint surface of the laminated body must withstand the processing temperature.
Among the semiconductor thin films, Si has a coefficient of linear expansion of about 3 ppm / ° C. When this thin film is deposited on a substrate, if the difference in the coefficient of linear expansion between the substrate and the thin film is large, stress is generated in the thin film. It may cause accumulation, deterioration of performance, warpage of thin film, and peeling. In particular, when a high temperature is applied during the thin film forming process, the stress due to the difference in the coefficient of linear expansion between the substrate and the thin film increases during the temperature change.
In the production of the low-temperature polysilicon thin film, a treatment such as 450 ° C. for 2 hours may be required in the dehydrogenation step. Further, in order to prepare a hydrogenated amorphous silicon thin film, a temperature of about 200 ° C. to 300 ° C. may be applied to the substrate. At this time, the thermoplastic resin as the polymer film does not satisfy the performance.
Conventionally, it has been widely practiced to attach a polymer film to an inorganic substrate and process it using an adhesive or an adhesive (Patent Document 1). However, when a process in a temperature range of about 200 to 500 ° C. such as polysilicon or an oxide semiconductor is required, a bonding adhesive or adhesive having sufficient resistance for practical use was used. The method is unknown.
As a method for avoiding the problem of heat resistance without using an adhesive, an adhesive, etc., a step of forming a resin substrate on a fixed substrate via an amorphous silicon film as a release layer and a step of forming the resin substrate on the resin substrate. At least a step of forming a TFT element and a step of peeling the resin substrate from the fixed substrate in the amorphous silicon film by irradiating the amorphous silicon film with laser light are performed, and the resin substrate is formed. Although it is disclosed in (Patent Document 2) that a display device having flexibility is produced by using a resin, the adhesive layer is irradiated with a laser or an etching means is used for peeling, which causes a complicated process and high cost. become.

In view of this situation, the present inventors have used a bonding method in which a polyimide film and an inorganic substrate such as a glass substrate are bonded to each other by using a silane coupling agent treatment to withstand a high temperature process of 400 ° C. to 500 ° C., and the method thereof. We have made proposals for laminates. (Patent Documents 3 to 5)
Further, as an application of such a method, a surface treatment and a selective inactivation treatment are used together on the inorganic substrate side, and a good adhesive portion having a relatively strong adhesive strength between the polyimide film and the inorganic substrate and a relatively weak easily peeling portion are used. The good adhesive part and the easy-peelable part are mainly provided on the outer peripheral part of the inorganic substrate, and the easy-peelable part is provided in the inner area. We proposed a technology that can peel off the device part formed in the easily peelable part together with the polyimide film with low stress by making a notch at the boundary between the two. (Patent Document 6)

Japanese Unexamined Patent Publication No. 2008-159935 JP-A-2009-260387 Japanese Patent No. 5152104 Japanese Patent No. 51265555 Japanese Patent No. 5152429 JP-A-2015-37441

In the technique disclosed in Patent Document 6, the surface of the inorganic substrate treated with the silane coupling agent is partially covered with a mask or the like, and blast treatment, vacuum plasma treatment, atmospheric pressure plasma treatment, corona treatment, active radiation irradiation treatment, By performing at least one inactivation treatment selected from the group consisting of active gas treatment and chemical treatment, the part covered with the mask is a good adhesive part and the part subjected to the inactivation treatment is easily peeled off. It is a department.
The laminate obtained by this method has sufficient resistance to semiconductor device manufacturing processes including vacuum process, wet processing process, high temperature processing process, etc., and the easily peeled part can be easily peeled from the substrate. It is extremely useful in industry, which makes it possible to manufacture flexible devices without destroying the devices.
However, in such a technique, when there is a step of being exposed to a high temperature in the manufacturing process of a flexible device, the adhesive strength of the easily peeled portion increases and peeling becomes difficult, so that the boundary between the good bonded portion and the easily peeled portion is formed. Was sometimes ambiguous.
In addition, when the mask is floated so as not to come into direct contact with the inorganic substrate, the inactivation treatment wraps around the gap between the mask and the inorganic substrate, and the boundary between the good adhesive portion and the easily peelable portion becomes ambiguous and unclear. Has occurred.
If the boundary between the good adhesive part and the easy peeling part is ambiguous, the peripheral part that should have been strongly adhered will peel off during the process, or stress will be applied to the device during the peeling operation of the part that should be easy peeling, and the device will break. This causes a problem that leads to a decrease in yield.

As a result of diligent studies, the present inventors have obtained heat resistance and insulation properties in which a polyimide film having a higher level of heat resistance and flexibility and an inorganic substrate such as a glass plate, a ceramic plate, a silicon wafer, or a metal are laminated. We have found a laminate that is excellent in terms of quality, has a good adhesive portion and an easily peelable portion with a clear boundary, and is useful for forming a flexible device, and a method for producing the same.
That is, the present invention has the following configuration.
[1] In a method for producing a laminate in which a substrate made of an inorganic substance treated with a silane coupling agent and a surface-treated polyimide film are superposed and adhered to each other and bonded to each other by heating, the surface treatment of the polyimide film is performed. The production of a laminate comprising a step of contacting with an aqueous surfactant containing potassium hydroxide having a temperature of 12 ° C. or higher, 48 ° C. or lower, pH 8.5 or higher and 10.5 or lower for 10 seconds or longer. Method.
[2] The lamination according to [1], which comprises a step of reducing the moisture absorption rate of the polyimide film to 0.5% or less by drying at a temperature of 80 ° C. or higher after the surface treatment of the polyimide film. How to make a body.
[3] By partially inactivating the surface of the inorganic substance treated with the silane coupling agent, a good adhesive portion having a high adhesive strength of the polyimide film to the substrate and an easily peelable portion having a low adhesive strength are formed. The method for producing a laminate according to [1] or [2].
[4] The laminate according to any one of [1] to [3], wherein the thickness of the silane coupling agent layer formed by the silane coupling agent treatment is 50 nm or less.
[5] The laminate according to any one of [1] to [4], wherein the area of the inorganic substrate is 1700 square cm or more.
[6] The inactivation treatment is a treatment for exposing plasma to the substrate surface by passing the coupling agent-treated substrate between a pair of opposing electrodes in which plasma is generated by an alternating electric field. The method for producing a laminate according to any one of [1] to [5], wherein the frequency of the alternating electric field is 8 kHz or more and 300 kHz or less, and the electric field strength is 45 kV / m or more and 240 kV / m or less.
[7] The inactivation treatment is characterized in that the substrate is irradiated with plasma generated by an alternating electric field having a frequency of 8 kHz or more and 300 kHz or less in atmospheric pressure with an electric field strength of less than 45 kV / m. The method for producing a laminate according to any one of [1] to [5].

In the present invention, it is a laminated plate in which a polyimide film subjected to a specific surface treatment and an inorganic substrate such as glass are bonded via an ultra-thin silane coupling agent layer, and is preferably in a good bonded state and easily adhered. A peeling portion is provided, and the transition region from strong adhesion to easy peeling existing at the boundary between the two is extremely narrow. The present invention is to obtain a flexible electronic device by adhering and holding a polyimide film using an inorganic substrate as a temporary support, processing a fine device such as a fine circuit or a thin film TFT on the surface of the polyimide film, and then peeling the polyimide film from the inorganic substrate. Used for.
In the present invention, the greatest effect is that the adhesive strength between the polyimide and the inorganic substrate is stable, and a laminate in which the adhesive strength does not change significantly even after being exposed to a high temperature exceeding 400 ° C. can be realized.
In the present invention, by further combining with a specific inactivation treatment, the transition region of the strength of the peel strength is narrow and the boundary between the good adhesive portion and the easy peel portion is clear, so that the margin outside the device formation region is set. Since it can be made smaller, the effective area is expanded, the product yield is increased, and the productivity is improved. As a result of providing a clearer boundary, when the region on which the fine device is formed is peeled off, it becomes easy to obtain a trigger for peeling, and the production efficiency is improved.
Further, in the past, some curl was often seen at the end of the film at the portion peeled from the easily peeled portion, but when peeled from the laminate having a narrow transition region of the present invention, the curl at this end was conspicuous. It has disappeared and it has been found that the flatness of the resulting product has been improved.

FIG. 1 is a conceptual diagram showing an example of a measurement result showing a difference in adhesive strength between a good adhesive portion and an easily peelable portion obtained in the present invention.

The polyimide film used in the present invention is a polyamic acid film obtained by applying a solution of tetracarboxylic acid dianhydride and a polyamic acid obtained from a diamine to a substrate and drying the polyamic acid film to become self-supporting, and further dehydrating and condensing it by heat treatment or the like. It is a condensate obtained by reacting. The polyimide used in the present invention is preferably a condensate obtained from aromatic tetracarboxylic dianhydride and diamine.
Examples of fragrant tetracarboxylic acids include pyromellitic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic acid dianhydride, 3,3. ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) ) Phenyl] Proanoic acid anhydride and the like can be used. These tetracarboxylic dianhydrides may be used alone or in combination of two or more. When heat resistance is important, the aromatic tetracarboxylic acids are, for example, preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more of all tetracarboxylic acids.

In the present invention, a polyimide film made of an alicyclic tetracarboxylic acid can be used. Examples of the alicyclic tetracarboxylic acid include cyclobutanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3', 4,4'-bicyclohexyltetracarboxylic acid and the like. Examples include carboxylic acids and their acid anhydrides. Among these, dianhydrides having two anhydride structures (eg, cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3', 4,4 '-Bicyclohexyltetracarboxylic dianhydride, etc.) is suitable.

As the diamine preferably used in the present invention, phenylenediamine, diphenylaminoether, and aromatic diamines having a benzoxazole structure can be used. Specific examples of the aromatic diamines having a benzoxazole structure include the following, and it is possible to use two or more kinds of the diamines alone.

The molecular structure of aromatic diamines having a benzoxazole structure is not particularly limited, and specific examples thereof include the following. For example, 5-amino-2- (p-aminophenyl) benzoxazole, 6-amino-2- (p-aminophenyl) benzoxazole, 5-amino-2- (m-aminophenyl) benzoxazole, 6-amino -2- (m-aminophenyl) benzoxazole, 2,2'-p-phenylenebis (5-aminobenzoxazole), 2,2'-p-phenylenebis (6-aminobenzoxazole), 1- (5) −Aminobenzoxazole) -4- (6-aminobenzoxazolo) benzene, 2,6- (4,4'-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2,6- (4,4'-diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole, 2,6- (3,4'-diaminodiphenyl) benzo [1,2-d: 4,5-d'] d: 5,4-d'] bisoxazole, 2,6- (3,4'-diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole, 2,6- (3, 3'-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2,6- (3,3'-diaminodiphenyl) benzo [1,2-d: 4,5-d '] Examples include bisoxazole.

Among these, each isomer of amino (aminophenyl) benzoxazole is preferable, and 5-amino-2- (p-aminophenyl) benzoxazole is more preferable from the viewpoint of easiness of synthesis. Here, "each isomer" is each isomer in which two amino groups of amino (aminophenyl) benzoxazole are defined according to the coordination position (eg, "Chemical formula 1" to "Chemical formula 4" above. Each compound described in). These diamines may be used alone or in combination of two or more.

In the present invention, one or more of the diamines exemplified below may be used in combination as long as it is 30 mol% or less of the total diamine. Examples of such amines include 4,4'-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, and bis [4- (3-aminophenoxy) phenyl]. Sulfates, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3'-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'- Diaminodiphenylsulfoxide, 3,3'-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4 '-Diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4 -(4-Aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] propane, 1,2 -Bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane , 1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane, 1,4-bis [4- (4-aminophenoxy) phenyl] ) Phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) phenyl] butane, 2- [4- (4-amino) Phenoxy) phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-a) Minophenoxy) -3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2- Bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexa Fluoropropane, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4) -Aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [ 4- (4-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,3-bis [4- (4) -Aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 4,4'-bis [(3-Aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) phenyl] propane, 3,4 '-Diaminodiphenyl sulfide, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl ] Methan, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl ] Sulfoxide, 4,4'-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [4- (4-Amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- ( 4-Aminophenoxy) Phenoxy} Enyl] sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethyl] Benzene] Benzene, 1,3-bis [4- (4-amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluoro) Phenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4) -Amino-6-cyanophenoxy) -α, α-dimethylbenzyl] benzene, 3,3'-diamino-4,4'-diphenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3,4'-Diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxy Benzenephenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4 '-Diamino-4,5'-dibiphenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 4,4'-diamino-5-biphenoxybenzophenone, 3,4'-diamino-4-biphenoxy Benzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) benzene, 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) Benzene, 1,4-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino-5-) Biphenoxybenzoyl) benzene, 2,6-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzonitrile and some or all of the hydrogen atoms on the aromatic ring of the above aromatic diamine are c. A logene atom, an alkyl or alkoxyl group having 1 to 3 carbon atoms, a cyano group, or an alkyl halide group having 1 to 3 carbon atoms in which a part or all of the hydrogen atoms of the alkyl group or alkoxyl group are substituted with halogen atoms Examples thereof include aromatic diamines substituted with an alkoxyl group.

The solvent used when reacting (polymerizing) aromatic tetracarboxylic acids with aromatic diamines to obtain polyamic acid is not particularly limited as long as it dissolves both the raw material monomer and the produced polyamic acid. However, polar organic solvents are preferred, for example, N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, Examples thereof include hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, and halogenated phenols. These solvents can be used alone or in admixture. The amount of the solvent used may be an amount sufficient to dissolve the monomer as a raw material, and as a specific amount used, the weight of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by weight. The amount is preferably 10 to 30% by weight.

The polyimide film of the present invention preferably has a coefficient of linear expansion (both in the length direction and the width direction of the film) of −5 ppm / ° C. to + 20 ppm / ° C. In the polyimide film of the present invention, it is preferable that no glass transition point is observed in a region where the glass transition temperature is 250 ° C. or higher, preferably 300 ° C. or higher, more preferably 350 ° C. or higher, or 500 ° C. or lower. The glass transition temperature in the present invention is determined by differential thermal analysis (DSC).

The thickness of the polyimide film in the present invention is not particularly limited, but is preferably 1 μm to 200 μm, more preferably 3 μm to 60 μm. The thickness unevenness of these polyimide films is also preferably 20% or less. If it is 1 μm or less, it is difficult to control the thickness, and it is difficult to peel it off from the substrate made of an inorganic substance. If the thickness is 200 μm or more, the polyimide film is likely to be bent when the polyimide film is peeled off. By using these polyimide films, it is possible to greatly contribute to improving the performance of elements such as sensors and making electronic components lighter, smaller, shorter and thinner.

In the polyimide film of the present invention, in order to ensure handleability and productivity, a layer (polyimide film) in which a lubricant is added / contained in the polyimide to impart fine protrusions on the surface of the layer (polyimide film). It is preferable to ensure slipperiness. The protrusions due to the lubricant particles may be present on both sides of the film, or may be present on only one side. By passing through a polyamic acid containing a lubricant and a multilayer polyamic acid in which a polyamic acid without a lubricant is laminated, a film having lubricant protrusions on only one side can be obtained.

In the present invention, the polyimide film is surface-treated. The surface treatment of the polyimide film in the present invention is an aqueous surfactant solution containing potassium hydroxide having a temperature of 12 ° C. or higher, 48 ° C. or lower, a pH of 8.5 or higher and 10.5 or lower (hereinafter, abbreviated as surface treatment liquid). Including the step of contacting for 10 seconds or more. It is more preferable that the pH at the time of surface treatment is 9.5 or more and 10.9 or less. The contact time between the surface treatment liquid and the polyimide film is sufficient for 10 seconds or more, but it is preferable to contact the polyimide film for 30 seconds or more, preferably 60 seconds or more from the viewpoint of the size of the polyimide film, wet spread on the film surface, and process control. .. Further, the upper limit of the contact time is preferably 30 minutes or less, more preferably 10 minutes or less, still more preferably 5 minutes or less from the viewpoint of process control or throughput.
As a method of bringing the polyimide film into contact with the surface treatment liquid, a dip method can be used in the laboratory and a spray method can be used in the industrial production.

As the surfactant used in the surface treatment liquid of the present invention, anionic, nonionic, and cationic surfactants can be used. Particularly preferably, an anionic surfactant and a nonionic surfactant can be used in combination.
Examples of the anionic surfactant include alkyl sulfonates, alkyl benzene sulfonates, alkyl carboxylic acid salts, alkyl benzene carboxylic acid salts, alkyl phosphates, alkyl benzene phosphates and the like, and the use of alkyl benzene sulfonates is preferable. .. In the present invention, these alkali metal salts, ammonium salts, alkylammonium salts, dialkylammonium salts, trialkylammonium salts, tetraalkylammonium salts, monoalkanolamine salts, dialkanolamineenes, and trialkanolamine salts can be used. The use of potassium salts is preferred in the present invention.
The nonionic surfactant used in the present invention may be understood as a water-soluble compound having a polyalkylene glycol chain in the molecule.

The total amount of the surfactant in the surface treatment liquid in the present invention is preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.3% by mass or less. The lower limit of the total amount is 0.003% by mass.
In addition to potassium hydroxide and a surfactant, a chelating agent may be added to the surface treatment liquid of the present invention for the purpose of capturing polyvalent metal ions in the surface treatment liquid. Further, a defoaming agent for suppressing foaming of the surface treatment liquid may be added. As the defoaming agent, it is preferable to add a water-soluble alcohol compound.
In the present invention, it is preferable that the polyimide film and the surface treatment liquid are brought into contact with each other for a predetermined time and then washed with water.

The present invention includes at least a step of bringing the polyimide film into contact with the surface treatment liquid, followed by a step of reducing the moisture absorption rate of the polyimide film to 0.5% or less by drying the polyimide film at a temperature of 80 ° C. or higher. preferable.
If the polyimide film has a high moisture absorption rate, it may cause poor adhesion or variation in adhesive strength in the bonding process with the inorganic substrate, and further, partial peeling of the film may occur in the device processing process after bonding with the inorganic substrate. May occur.

The substrate made of an inorganic substance in the present invention is mainly composed of a glass plate, a ceramic plate, a silicon wafer, and a metal, and a composite of these glass plates, a ceramic plate, a silicon wafer, and a metal, in which these are laminated. Those in which these are dispersed, those in which these fibers are contained, those in which a thin film made of these materials is formed on the surface, and the like can be used.

The glass plate as the substrate made of the inorganic substance in the present invention includes quartz glass, high silicate glass (96% silica), soda lime glass, lead glass, aluminoborosilicate glass, and borosilicate glass (Pylex (registered trademark)). , Borosilicate glass (non-alkali), borosilicate glass (microsheet), aluminosilicate glass. Among them, those having a coefficient of linear expansion of 5 ppm / ° C. or less are desirable, and Corning 7059, 1737, EAGLE, Asahi Glass AN100, Nippon Electric Glass OA10, SCHOTT AF32, etc. for liquid crystal glass are desirable.

The ceramic plate as the substrate made of the inorganic substance in the present invention includes alumina, mulite, AlN, SiC, Si3N4, BN, crystallized glass, Cordierite, Spodumene, Pb-BSG + CaZrO3 + Al2O3, Crystallized glass + AL2O3, Crystallized Ca-BSG. , BSG + Quartz, BSG + Quartz, BSG + AL2O3, Pb + BSG + AL2O3, Glass-ceramic, ceramics for substrates such as zerodur material, TiO2, strontium titanate, calcium titanate, magnesium titanate. Capacitor materials such as alumina, MgO, steatite, BaTi4O9, BaTiO3, BaTi4 + CaZrO3, BaSrCaZrTio3, Ba (TiZr) O3, PMN-PT PFN-PFW, PbNb2O6, Pb0.5Be0.5Nb2O6, PbTiO3, BaTiO3, PbTiO3, BaTiO3 Includes piezoelectric materials such as 95PT-0.5BT, 0.873PZT-0.97PT-0.3BT, PLZT.

The silicon wafer as a substrate made of the inorganic substance in the present invention includes all n-type or p-type doped silicon wafers and intrinsic silicon wafers, and a silicon oxide layer and various types on the surface of the silicon wafer. In addition to silicon wafers including silicon wafers on which thin films are deposited, germanium, silicon-germanium, gallium-arsenide, aluminum-gallium-indium, and nitrogen-phosphorus-arsenide-antimony are often used. Includes general purpose semiconductor wafers such as InP (indium phosphide), InGaAs, GaInNAs, LT, LN, ZnO (zinc oxide), CdTe (cadmium telluride), ZnSe (zinc selenide).

Examples of the metal as the substrate made of the inorganic substance in the present invention include single element metals such as tungsten, molybdenum, platinum, gold, silver, iron, nickel, aluminum and titanium, stainless steel, inconel, monel, mnemonic and carbon steel. Alloys such as silicon steel, Fe—Ni-based Invar alloys, Super Invar alloys, brass, white copper, bronze, and duralmin are included. Further, a multilayer metal plate in which another metal layer and a ceramic layer are added to the above metal is also included.

A silane coupling agent treatment is required on at least the adhesive surface side of the inorganic substrate of the present invention with the polyimide film.
The coupling agent preferably used in the present invention preferably has an amino group or an epoxy group. Specific examples of the coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl). ) -3-Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2-( 3,4-Epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane vinyl trichlorosilane, vinyltri Methoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl Triethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3- Acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3 -Chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanuppropyltriethoxysilane, tris-(3-trimethoxysilylpropyl) ) Isocyanurate, chloromethylphenetyltrimethoxysilane, chloromethyltrimethoxysilane and the like.
Other possible coupling agents include 1-mercapto-2-propanol, 3-mercaptopropionate methyl, 3-mercapto-2-butanol, 3-mercaptopropionate butyl, 3- (dimethoxymethylsilyl)-. 1-Propanethiol, 4- (6-mercaptohexaloyl) benzyl alcohol, 11-amino-1-undecenethiol, 11-mercaptoundecylphosphonic acid, 11-mercaptoundecyltrifluoroacetic acid, 2,2'-( Ethylenedioxy) diethanethiol, 11-mercaptoundecyltri (ethylene glycol), (1-mercaptoundic-11-yl) tetra (ethylene glycol), 1- (methylcarboxy) undec-11-yl) hexa ( (Ethylene glycol), hydroxyundecyl disulfide, carboxyundecyl disulfide, hydroxyhexadodecyl disulfide, carboxyhexadecyl disulfide, tetrax (2-ethylhexyloxy) titanium, titanium dioctyloxybis (octylene glycolate), zirconium tributoxymonoacetyl Examples thereof include acetonate, zirconium monobutoxyacetylacetonate bis (ethylacetacetate), zirconium tributoxymonostearate, and acetoalkoxyaluminum diisopropyrate.

Of these, those preferred are N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl). ) -3-Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- ( 3,4-Epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, aminophenyltrimethoxysilane , Aminophenylaminomethylphenetyltrimethoxysilane, aminophenylaminomethylphenetyltrimethoxysilane and the like. When heat resistance is required in the process, an aromatic connection between Si and an amino group can also be preferably used. In the present invention, these silane coupling agents can be used alone or in combination of two or more.

The treatment with a silane coupling agent in the present invention means forming a thin layer made of a silane coupling agent on the surface of a substrate, and may be paraphrased as coating. Examples of the method for treating the coupling agent in the present invention include a method in which a solution of the coupling agent is applied to a substrate made of an inorganic substance, dried and heat-treated, and a method in which the substrate is immersed in the solution of the coupling agent and then dried and heat-treated. it can.
There is an upper limit to the thickness of the silane coupling agent layer in order to effectively realize the present invention. The thickness of the silane coupling agent layer in the present invention is essential to be 100 nm or less, preferably 60 nm or less, more preferably 25 nm or less, still more preferably 12 nm or less. As a method for uniformly forming the silane coupling agent layer in such a thin region, a vapor phase coating method of the silane coupling agent can be exemplified. The film thickness of the silane coupling agent layer can be determined by an ellipsometry method.

In the present invention, as a method for treating the silane coupling agent, a method of applying the silane coupling agent to the surface of the substrate via the gas phase can be preferably used. That is, it is a method of exposing a substrate made of an inorganic substance to the vapor of the silane coupling agent, that is, the silane coupling agent in a substantially gaseous state. The vapor of the silane coupling agent can be obtained by a bubbling method, a baking method, etc., but if it is accompanied by heating at 200 ° C. or higher, it may cause a side reaction of the silane coupling agent, so it is used at a temperature lower than 200 ° C. Is preferable. It is more preferable to obtain the silane coupling agent vapor at 100 ° C. or lower, more preferably 40 ° C. or lower.

The carrier gas used to obtain the silane coupling agent vapor is preferably a dry gas having a dew point of −5 ° C. or lower. It is more preferable to use a dry gas having a dew point of −30 ° C. or lower, and even more preferably a dew point of −50 ° C. or lower. Moisture mixing in the carrier gas causes a side reaction of the silane coupling agent, hinders the stable supply of the silane coupling agent vapor, and also causes the generation of foreign matter derived from the silane coupling agent in the apparatus.

Since more silane coupling agents are flammable liquids, it is preferable to use an inert gas as the carrier gas, especially when a heat source is used. When a silane coupling agent layer is formed on a substrate by introducing silane coupling agent vapor into an apparatus in which a substrate made of an inorganic substance is installed, exposure is required to obtain a thickness of 100 nm or less required by the present invention. The duration is preferably 18 minutes or less, more preferably 6 minutes or less, still more preferably 2 minutes or less, and even more preferably 40 seconds or less.

The substrate temperature during the formation of the silane coupling agent layer on the substrate made of an inorganic substance is an appropriate temperature between -50 ° C and 200 ° C depending on the type of the silane coupling agent and the desired thickness of the silane coupling agent layer. It is preferable to control the temperature. However, from the viewpoint of work efficiency, it is preferable to set the temperature lower than the temperature at which the silane coupling agent vapor is generated. It is preferable to set the temperature to 5 ° C. or higher, more preferably 10 ° C. or higher.

The substrate made of the inorganic substance on which the silane coupling agent layer is formed is preferably heated to 70 ° C. to 200 ° C., more preferably 75 ° C. to 150 ° C. after exposure. By such heating, the hydroxyl group and the like on the surface of the substrate react with the alkoxy group and the silazane group of the silane coupling agent, and the silane coupling agent treatment is completed. The time required for heating is 0.1 seconds or more and 10 minutes or less. If the temperature is too high or the time is too long, the coupling agent may deteriorate. If the temperature is too low or the time is too short, the processing effect cannot be obtained. If the substrate temperature during exposure to the silane coupling agent is already 80 ° C. or higher, the subsequent heating can be omitted.

It is a preferable operation to clean the surface of the inorganic substrate before the treatment with the silane coupling agent by means such as short wavelength UV / ozone irradiation, or to clean the surface with a liquid cleaning agent.

In the present invention, a portion having a relatively high adhesive strength of the polyimide film to the inorganic substrate is referred to as a good adhesive portion, and a portion having a relatively low adhesive strength is referred to as an easy peeling portion.
FIG. 1 is an example of typical measurement results when the adhesive strength of a polyimide film is measured in the laminate of the present invention. The region S with high adhesive strength is a good adhesive portion, the region W with low adhesive strength is an easily peelable portion, and G is a transition region between the two.
In the present invention, when the average adhesive strength of the good adhesive portion is T ₁ , the average adhesive strength of the easily peelable portion is T _2, and the difference in adhesive strength is T = T _{1 −} T ₂ , the adhesive strength is T _{1 −} 0. It is preferable that the distance G from the position of 1 × T to the position of T ₁ −0.9 × T, that is, the width of the transition region G is 4 mm or less. The width G of the transition region is more preferably 3 mm or less, further preferably 2.4 mm or less, and further preferably 1.5 mm or less.

In the present invention, the adhesive strength of the portion of the inorganic substrate irradiated with atmospheric pressure plasma is reduced to become an easy-adhesive portion, and the portion not irradiated with atmospheric pressure plasma becomes a good adhesive portion. In the atmospheric pressure plasma treatment of the present invention, the boundary between the treated portion and the untreated portion is very clear, so that it is possible to clarify the boundary between the good adhesive portion and the easily peeled portion without using a mask. ..
Further, by not using a mask, it is possible to reduce the risk of scratches, contamination, and foreign matter adhering to the film surface. The required adhesive strength varies depending on each process. However, as a general theory, the 90-degree adhesive strength of the good adhesive portion between the laminated polyimide film and the substrate made of an inorganic substance is preferably 0.5 N / cm or more and 5 N / cm or less, and more preferably 0.8 N. / Cm or more and 2 N / cm or less. The 90-degree adhesive strength of the easily peeled portion is preferably 1/2 or less of that of the good bonded portion, and when the adhesive strength of the easily peeled portion is 1 N / cm, the easily peeled portion is 0.01 N / cm or more and 0. It is preferably .4 N / cm or less, and the adhesive strength of the easily peeled portion is more preferably 1/2 or less of that of the good adhesive portion and 0.01 N / cm or more and 0.2 N / cm or less. However, the lower limit of the adhesive strength of the easily peeled portion is a value in which the bending energy of the polyimide film is taken into consideration.

The atmospheric pressure plasma treatment in the present invention refers to a treatment of exposing an object to be processed to plasma generated by an alternating electric field under a pressure in the range of 0.3 atm to 3 atm.
Examples of the atmospheric pressure plasma treatment in the present invention include a direct type atmospheric pressure plasma treatment, a remote type atmospheric pressure plasma treatment, and a spot type atmospheric pressure plasma treatment.

Direct atmospheric pressure plasma treatment can be shown as an example of preferable atmospheric pressure plasma treatment in the present invention. The direct atmospheric pressure plasma treatment is a method of performing plasma treatment by passing a sample to be irradiated with plasma between two electrodes generating plasma. More specifically, plasma is generated by electric discharge between two parallel electrodes facing each other, one electrode is arranged so as to be on the back side of the sample to be irradiated with plasma, and the generated plasma is pulled out from between the parallel electrodes to sample. It is a method of irradiating the plasma. Compared to remote type and spot type atmospheric pressure plasma processing, direct atmospheric pressure plasma processing has a higher plasma density and can efficiently reduce the adhesive strength in a shorter time, and can process a large area at once. It is preferable in that it is possible.

The direct atmospheric pressure plasma treatment in the present invention is a method of generating plasma between a set of electrodes installed facing each other and placing an object to be processed between them, in other words, for atmospheric pressure plasma in a strong electric field. This is a method of exposing the object to be treated.
In the present invention, the preferable electric field strength is in the range of 45 kV / m or more and 500 kV / m or less, and more preferably 80 kV / m or more and 240 kV / m or less. If the electric field strength exceeds this range, an abnormal discharge may occur, which may cause problems such as leaving a discharge mark on the object to be processed. Further, when the electric field strength is smaller than this range, the processing effect becomes small and the processing takes time, so that the productivity is lowered. The electric field strength referred to here is the electric field strength when the object to be processed is not between the electrodes.
In the atmospheric pressure plasma treatment in the present invention, the frequency of the alternating electric field for generating plasma is preferably 8 kHz or more and 300 kHz or less, more preferably 12 kHz or more and 120 kHz or less, and further 20 kHz or more and 80 kHz or less. It is preferable to have. If the frequency falls below this range, the stability of the discharge decreases and it becomes difficult for the plasma to stand. Further, when the frequency exceeds this range, the leakage current in the processing device increases, so that the energy efficiency decreases.

The distance between the opposing electrodes that generate plasma in the present invention is preferably in the range of a minimum of 0.4 mm and a maximum of 5.5 mm, and further preferably in a range of a minimum of 0.8 mm and a maximum of 4 mm. If the distance between the electrodes is narrower than this range, abnormal discharge is likely to occur, and if it exceeds this range, the applied voltage for obtaining the required electric field strength becomes too high, and the power supply cost increases.
In the present invention, it is preferable that the distance between the electrode facing at least the coupling agent-treated surface of the substrate and the silane coupling agent-treated surface is 0.3 mm or more and 5.0 mm or less. Further, it is preferable to carry out the treatment in the range of 1.2 mm or more and 3.7 mm or less. If the distance between the electrode and the treated surface is less than this range, a problem may occur due to contact between the object to be processed and the electrode. Further, if the distance between the two exceeds this range, the processing effect becomes small, the processing requires a long time, the productivity decreases, and the plasma is diffused, so that the transition region of the strength of the adhesive strength tends to be widened.

Examples of the plasma treatment gas used in the present invention include hydrogen, helium, nitrogen, oxygen, argon, carbon tetrafluoride, dry air, and a mixed gas thereof, and nitrogen or dry air is preferable. The dew point of the dry air is preferably −5 ° C. or lower, more preferably −10 ° C. or lower, and further preferably −20 ° C. or lower.
In the atmospheric pressure plasma treatment of the substrate in the present invention, both the electrode and the substrate may be treated for a certain period of time without moving, or either or both of the electrode and the substrate may be treated while moving at a constant speed. .. Assuming that the irradiation time is the time from the start of irradiating the plasma to any one point in the atmospheric pressure plasma irradiation range on the substrate to the end of the irradiation, the preferable irradiation time is 0.5 seconds or more and 15.0 seconds or less. More preferably, it is 0.7 seconds or more and 12.0 seconds or less. Here, the time from the start of plasma irradiation to the end of irradiation means the time for the object to be processed to pass between the opposing electrodes that generate plasma. Strictly speaking, in the traveling direction of the object to be processed, the time required to pass between the surface connecting the electrode edges on the inlet side of the opposing electrodes and the surface connecting the edges of the electrodes on the exit side of the opposing electrodes. is there.

In the present invention, a remote plasma treatment can be exemplified as an atmospheric pressure plasma treatment that can be preferably used.
The remote plasma treatment in the present invention is a treatment for exposing an object to be processed to plasma generated by an alternating electric field under a pressure in the range of 0.3 atm to 3 atm, and is an alternating electric field having a frequency of 8 kHz or more and 300 kHz or less. This is a process of irradiating the substrate with the plasma generated by the above in a state where the electric field strength is less than 45 kV / m. In the present invention, the electric field strength is preferably less than 20 kV / m, and more preferably less than 5 kV / m. In the present invention, it is preferable not to actively accelerate the electric field of the plasma and not to apply an external electric field higher than the electric field generated by charging by plasma irradiation.

In the remote atmospheric pressure plasma processing in the present invention, the frequency of the alternating electric field for generating plasma is preferably 8 kHz or more and 300 kHz or less, more preferably 12 kHz or more and 120 kHz or less, and further 20 kHz or more and 80 kHz or less. It is preferable to have. If the frequency falls below this range, the stability of the discharge decreases and it becomes difficult for the plasma to stand. Further, when the frequency exceeds this range, the leakage current in the processing device increases, so that the energy efficiency decreases.

In the remote atmospheric pressure plasma treatment in the present invention, the shape of the outlet from which the plasma is supplied to the substrate to be processed is preferably a slit shape or a spot shape. In the case of a slit shape, the width of the plasma supply port is preferably 0.2 mm or more and 10 mm or less, more preferably 0.4 mm or more and 5 mm or less, and further preferably 0.5 mm or more and 3 mm or less. In the case of a spot shape, the diameter of the plasma supply port is preferably 0.2 mm or more and 10 mm or less, more preferably 0.4 mm or more and 5 mm or less, and further preferably 0.5 mm or more and 3 mm or less. If the width or diameter of the plasma supply port is too small, the amount of plasma supplied is limited, which is not preferable. If it is too large, the plasma density in the gas is lowered and the effect of lowering the adhesive strength is diminished, which is not preferable.
The plasma flow rate in the present invention is defined by the flow rate of the gas supplied to the plasma generated by the alternating electric field, and is preferably 10 L / min or more and 300 L / min or less, and more preferably 30 L / min or more and 250 L / min or less. More preferably, it is 50 L / min or more and 200 L / min or less. If the plasma flow rate is too small, the amount of plasma supplied will be limited and the plasma will stay around the processing section, making the transition region of the adhesive strength unclear, which is not preferable. If the plasma flow rate is too large, the plasma density in the gas will decrease. It is not preferable because the effect of reducing the adhesive strength is diminished.
In addition, since a large amount of gas containing plasma is generated, it is preferable to provide a forced exhaust function in the equipment for performing this plasma treatment so that the atmosphere is constantly changed.

Examples of the plasma treatment gas used in the present invention include hydrogen, helium, nitrogen, oxygen, argon, carbon tetrafluoride, dry air, and a mixed gas thereof, and nitrogen or dry air is preferable. The dew point of the dry air is preferably −5 ° C. or lower, more preferably −10 ° C. or lower, and further preferably −20 ° C. or lower.

In the atmospheric pressure plasma treatment of the substrate in the present invention, both the electrode and the substrate may be treated for a certain period of time without moving, or either or both of the electrode and the substrate may be treated while moving at a constant speed. .. Assuming that the irradiation time is the time from the start of plasma irradiation to any point within the atmospheric pressure plasma irradiation range on the substrate to the end of irradiation, the preferable irradiation time is 0.1 seconds or more and 10.0 seconds or less. More preferably, it is 0.3 seconds or more and 8.0 seconds or less. Here, the time from the start of plasma irradiation to the end of irradiation means the time for the object to be processed to pass between the opposing electrodes that generate plasma. Strictly speaking, in the traveling direction of the object to be processed, the time required to pass between the surface connecting the electrode edges on the inlet side of the opposing electrodes and the surface connecting the edges of the electrodes on the exit side of the opposing electrodes. is there.

In the present invention, the pressure heat treatment preferably used when laminating a surface-treated polyimide film on a substrate made of an inorganic substance refers to press, laminate, and roll laminate, each of which is performed while applying temperature, and is preferably performed. These operations are performed in a vacuum. For pressing in vacuum, for example, pressing with 11FD manufactured by Imoto Seisakusho, or a film laminator that can apply pressure to the entire surface of the glass at once with a roll-type film laminator after evacuating or a thin rubber film after evacuating A method such as vacuum lamination by MVLP of Meiki Co., Ltd. can be used. Further, in the present invention, the pressurization step and the heating step may be sequentially performed. For example, a method such as laminating with a roll laminator and then heating in a dry oven can be exemplified.

Preferred pressurization methods include ordinary pressing in the air or pressing in vacuum, but in order to obtain stable adhesive strength over the entire surface, pressing in vacuum is more preferable. As for the degree of vacuum, a vacuum using a normal oil rotary pump is sufficient, and about 10 Torr or less is sufficient. The preferred pressure for pushing the sample is 1 MPa to 20 MPa, more preferably 3 MPa to 10 MPa. If the pressure is high, the substrate may be damaged, and if the pressure is low, some parts may not adhere to each other. The preferred heating temperature of the present invention is 150 ° C. to 400 ° C., more preferably 250 ° C. to 350 ° C.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The evaluation method of physical properties in the following examples is as follows.

<Reduced viscosity of polyamic acid solution>
The solution dissolved in N, N-dimethylacetamide so that the polymer concentration was 0.2 g / dl was measured at 30 ° C. using an Ubbelohde type viscosity tube.

<Thickness of polyimide film>
The thickness of the polyimide film was measured using a micrometer (“Millitron 1245D” manufactured by Fine Wolf Co., Ltd.).

<Tensile modulus, tensile strength and tensile elongation at break of polyimide film>
A strip-shaped test piece having a flow direction (MD direction) and a width direction (TD direction) of 100 mm × 10 mm is cut out from the film to be measured, and a tensile tester (Shimadzu Seisakusho Co., Ltd. “Autograph (registered trademark)) The tensile elastic modulus, tensile strength, and tensile elongation at break were measured in each of the MD direction and the TD direction under the conditions of a tensile speed of 50 mm / min and a distance between chucks of 40 mm using the model name AG-5000A).

<Coefficient of linear expansion (CTE) of polyimide film>
Regarding the flow direction (MD direction) and width direction (TD direction) of the polymer film to be measured, the stretch ratio was measured under the following conditions, and the intervals of 15 ° C. (30 ° C. to 45 ° C., 45 ° C. to 60 ° C.) The expansion / contraction rate / temperature at (...) was measured, this measurement was performed up to 300 ° C., and the average value of all the measured values measured in the MD direction and the TD direction was calculated as the linear expansion coefficient (CTE).
Device name; MAC Science "TMA4000S"
Sample length; 20 mm
Sample width; 2 mm
Temperature rise start temperature; 25 ° C
Temperature rise end temperature; 400 ° C
Temperature rise rate; 5 ° C / min Atmosphere; Argon initial load; 34.5 g / mm2

<Evaluation of polyimide film: slipperiness>
Two polyimide films are overlapped on different surfaces (that is, the outer surface and the inner surface of the film when wound as a film roll are overlapped instead of the same surfaces), and the overlapped polyimide films are sandwiched between the thumb and index finger. When the polymer film and the polymer film slipped when lightly rubbed together, it was evaluated as "○" or "good", and when it did not slip, it was evaluated as "x" or "poor". In some cases, the outer surfaces of the winding or the inner surface of the winding may not slip, but this is not an evaluation item.

<Appearance of laminated body>
A visual inspection of the laminate by an adult inspector with a visual acuity of 1.0 or higher was performed, and a blister (film floating: foreign matter entering between the substrate and the film) that correlates with the contamination of the substrate surface, especially the amount of adhering foreign matter, causes the film to form. The location where the film was lifted up like a tent and a space was created between the substrate and the film. Also called "bubble" or "float") was judged. Converted to the number per 100 square cm, the case where the number of blisters having a diameter of 0.2 mm or more was 0 to 3 was extremely small, 4 to 10 was small, 10 to 20 was large, and 21 or more was large.

<Easy peeling part, film appearance after peeling, edge curl>
An adult inspector with a visual acuity of 1.0 or more visually inspected the appearance of the film after peeling. The point of interest is the presence or absence of curl on the film edge. Neutralize the peeled film with a static elimination brush, place it on a flat metal surface plate with the side to be attached to the substrate facing down, and visually observe the presence or absence of floating of the film edge, and no curl is observed. The case was “⊚”, the case where the edge lift was less than 0.5 mm was “◯”, the case where 0.5 mm or more and less than 1.0 mm was “Δ”, and the case where 1.0 mm or more was “x”.
<Adhesive strength, transition area width>
According to the 90-degree peeling method of JIS K6854, the substrate and the film of the laminated body were peeled off, and the force (power) required for the peeling was recorded on the chart. The size of the actually produced material varies depending on the substrate, but the measurement point is positioned so that the boundary between the good adhesive part and the easily peelable part is almost in the center of the measurement part, and the length is at least 40 mm across the boundary. The distance was peeled off and measured.
The measuring device used was an Autograph AG-IS manufactured by Shimadzu Corporation, the measuring environment was a room temperature standard environment in the atmosphere, the peeling speed was 100 mm / min, and the measurement sample width was 10 mm.
The obtained chart typically has the form of FIG. 1, where T ₁ is the adhesive strength in the good adhesive region S and T ₂ is the adhesive strength in W, which is the easy peeling region, and T = T ₁ − T. ₂ and placed, from places where the adhesive strength is "T ₁ -0.1 × T", and the distance to the point where the adhesive strength is "T ₁ -0.9 × T" and the transition region G.

<Thickness of coupling treatment layer>
The thickness (nm) of the coupling treatment layer (SC layer) was separately prepared by applying and drying a coupling agent on a washed Si wafer in the same manner as in each Example and Comparative Example to prepare a sample. The film thickness of the coupling-treated layer formed on the Si wafer was measured by an ellipsometry method using a spectroscopic ellipsometer (“FE-5000” manufactured by Photol) under the following conditions.
Reflection angle range; 45 ° to 80 °
Wavelength range; 250 nm to 800 nm
Wavelength resolution; 1.25 nm
Spot diameter; 1 mm
tanΨ; Measurement accuracy ± 0.01
cosΔ; measurement accuracy ± 0.01
Measurement; Method Rotating detector method Deflection angle; 45 °
Incident angle; 70 ° fixed detector; 0 to 360 ° in 11.25 ° increments
Wavelength; 250nm-800nm
The film thickness was calculated by fitting by the nonlinear least squares method. At this time, the model is an Air / thin film / Si model.
n = C3 / λ4 + C2 / λ2 + C1
k = C6 / λ4 + C5 / λ2 + C4
The wavelength dependence C1 to C6 was obtained by the formula of.

<Pretreatment of inorganic substances>
Before applying the silane coupling agent, the surface of the substrate made of inorganic material is irradiated with UV light for 2 minutes using a UV / ozone cleaning reformer "SKR1102N-03" manufactured by LAN Technical Service Co., Ltd. to remove stains. I used it after.

<Application example 1>
A silane coupling agent layer was formed on the substrate under the following conditions using an apparatus for generating silane coupling agent vapor.
Non-alkali glass (OA-10G manufactured by Nippon Electric Glass Co., Ltd.) of 370 mm × 470 mm × 0.7 mmt was used as a substrate, set vertically on a glass stand, and placed in a chamber into which silane coupling agent vapor was introduced. Next, a silane coupling agent (“KBM-903” manufactured by Shin-Etsu Chemical Co., Ltd .: 3-aminopropyltrimethoxysilane) was added to a device that generates silane coupling agent vapor by sending a carrier gas to the liquid surface of the silane coupling agent. After adding 100 g and adjusting the temperature to 40 ° C., nitrogen gas was sent at a flow rate of 10 L / min. The generated silane coupling agent vapor was introduced into the chamber through a pipe and held for 20 minutes. Then, the substrate was taken out of the chamber and heat-treated on a hot plate at 110 ° C. for 1 minute to obtain a substrate S1 on which a silane coupling agent layer was formed.

<Application example 2>
The same operation as in Coating Example 1 was carried out except that the time for holding the non-alkali glass substrate in the chamber into which the silane coupling agent vapor was introduced was changed to 10 minutes to obtain the substrate S2.

<Application example 3>
The same operation as in Coating Example 1 was carried out except that the time for holding the non-alkali glass substrate in the chamber into which the silane coupling agent vapor was introduced was changed to 5 minutes to obtain the substrate S3.

<Application example 4>
Silane coupling agent (“KBM-903” manufactured by Shin-Etsu Chemical Co., Ltd .: 3-aminopropyltrimethoxysilane) 0.5 parts by mass and 99.5 parts by mass of isopropyl alcohol are stirred and mixed in a clean glass container and silane. It was used as a coupling agent solution. On the other hand, a 300 mm × 350 mm × 0.7 mmt Pyrex (registered trademark) glass plate is set in a spin coater manufactured by Japan Create Co., Ltd., and 50 ml of isopropyl alcohol is first dropped into the center of the glass and shaken off at 500 rpm for cleaning, and then. Approximately 30 ml of the previously prepared silane coupling agent solution was dropped onto the center of the glass plate, and the mixture was rotated at 500 ml for 10 seconds, then the rotation speed was increased to 1500 rpm for 20 seconds, and the silane coupling agent solution was shaken off. Next, the glass plate is taken out from the stopped spin coater, placed on a hot plate at 100 ° C. with the silane coupling agent coated surface facing up, and heat-treated for about 3 minutes to form a silane coupling agent layer. The inorganic substrate S4 was obtained.

The cloth-inorganic substrate on which the silane coupling agent layer was formed as described above was partially inactivated to form a latent image of a good adhesive portion and an easily peelable portion.
<Inactivation treatment 1>
The inactivation treatment 1 is a direct atmospheric pressure plasma treatment.
The silane coupling agent layer side of the obtained substrate S1 was subjected to atmospheric pressure plasma treatment by the following procedure using a normal pressure plasma surface treatment device "AP-T05-S320 type" manufactured by Sekisui Chemical Co., Ltd. That is, the substrate 1 is placed on the stage serving as one of the electrodes, and the head with the pair of electrodes attached thereto has a gap distance of 1.3 mm between the silane coupling agent layer side of the substrate and the electrode attached to the head. Arranged as. While flowing nitrogen gas with a dew point of -20 ° C at a flow rate of 18 L / min, a voltage of 240 V is applied between the electrodes at a frequency of 30 kHz to generate plasma, and the head passes over the substrate treated with a silane coupling agent at a speed of 1000 mm / min. By doing so, atmospheric pressure plasma treatment was performed. The irradiation width of the plasma was set to 70 mm, and the time (irradiation time) from the start of the plasma irradiation to any one point in the irradiation range to the end of the irradiation was 1.8 seconds.
<Inactivation treatment 2>
The inactivation treatment 2 is a remote atmospheric pressure plasma treatment.
The silane coupling agent layer side of the obtained substrate S1 was subjected to the following procedure using a normal pressure plasma surface treatment device "AP-T05-S320" manufactured by Sekisui Chemical Co., Ltd. with a modified plasma blowing nozzle and power supply. Atmospheric pressure plasma treatment was performed.
The substrate 1 was placed on an XY stage installed in a box chamber having an internal capacity of 3 cubic meters having a ventilation function, and a plasma blowing nozzle having a nozzle diameter of 1 mmφ was installed on the substrate 1 at a distance of 1.5 mm from the surface of the substrate.
Plasma generated by applying a voltage of 240 V between the electrodes at a frequency of 30 kHz while flowing nitrogen gas with a dew point of -20 ° C between the pair of electrodes with a plasma source distance of 2 mm at a flow rate of 130 L / min. Was guided to the plasma blowing nozzle, and the XY stage was operated so that the nozzle moved at a relative speed of 100 mm / min on the substrate treated with the silane coupling agent, and a predetermined easily peeling portion pattern was drawn. The time (irradiation time) from the start of irradiating the plasma to any one point in the irradiation range to the end of the irradiation was 0.6 seconds.

<Manufacturing of polyimide film>
[Manufacturing Example 1]
(Preparation of polyamic acid solution)
After replacing the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod with nitrogen, 398 parts by mass of 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA) and paraphenylenediamine (paraphenylenediamine) ( 147 parts by mass of PDA) was dissolved in 4600 parts by mass of N, N-dimethylacetamide and added, and colloidal silica was dispersed in dimethylacetamide as a lubricant (Nissan Chemical Industry Co., Ltd. "Snowtex (registered trademark)). DMAC-ST30 ") was added so that silica (lubricant) was 0.15% by mass based on the total amount of polymer solids in the polyamic acid solution, and the mixture was stirred at a reaction temperature of 25 ° C. for 24 hours and shown in Table 1. A brown and viscous polyamic acid solution V1 having a reducing viscosity was obtained.

(Preparation of polyimide film)
The polyamic acid solution V1 obtained above is applied to a smooth surface (non-slip agent surface) of a long polyester film (“A-4100” manufactured by Toyobo Co., Ltd.) having a width of 1050 mm using a slit die to achieve a final film thickness (imide). The film was applied so that the film thickness after conversion was 25 μm, dried at 105 ° C. for 20 minutes, and then peeled off from the polyester film to obtain a self-supporting polyamic acid film having a width of 920 mm.
Next, the obtained self-supporting polyamic acid film was gradually heated in a temperature range of 150 ° C. to 420 ° C. by a pin tenter (first stage 180 ° C. × 5 minutes, second stage 270 ° C. × 10 minutes, The third stage was subjected to heat treatment (420 ° C. for 5 minutes) to imidize, and the pin gripping portions at both ends were dropped by slits to obtain a long polyimide film F1 (1000 m roll) having a width of 850 mm. The characteristics of the obtained film F1 are shown in Table 1.

[Manufacturing Example 2]
(Preparation of polyamic acid solution)
After replacing the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod with nitrogen, 223 parts by mass of 5-amino-2- (p-aminophenyl) benzoxazole (DAMBO) and N, N-dimethylacetamide 4416 A dispersion formed by adding colloidal silica as a lubricant and dispersing colloidal silica in dimethylacetamide together with 217 parts by mass of pyromellitic dianhydride (PMDA) (Snowtex (Nissan Chemical Industry Co., Ltd.)). Add the registered trademark) DMAC-ST30 ") so that the silica (lubricant) becomes 0.12% by mass based on the total amount of polymer solids in the polyamic acid solution, and stir at a reaction temperature of 25 ° C. for 24 hours. A brown and viscous polyamic acid solution V2 having a reduced viscosity shown in Table 1 was obtained.

(Preparation of polyimide film)
Using the polyamic acid solution V2 obtained above instead of the polyamic acid solution V1, a polyamic acid film was obtained by the same method, and then the first stage 150 ° C. × 5 minutes, the second stage 220 ° C. × It was imidized by heat treatment for 5 minutes and 3rd stage at 485 ° C. for 10 minutes, and the pin gripping portions at both ends were dropped by slits to obtain a long polyimide film F2 (1000 m roll) having a width of 850 mm. The characteristics of the obtained film F2 are shown in Table 1.

[Manufacturing Example 3]
(Preparation of polyamic acid solution)
In Production Example 2, the same procedure was carried out except that a dispersion in which colloidal silica was dispersed in dimethylacetamide (“Snowtex (registered trademark) DMAC-ST30” manufactured by Nissan Chemical Industries, Ltd.) was not added, and the polyamic acid solution V3 was operated in the same manner. Got

(Preparation of polyimide film)
The polyamic acid solution V2 obtained above was imidized on a smooth surface (non-slip agent surface) of a long polyester film (“A-4100” manufactured by Toyo Spinning Co., Ltd.) having a width of 1050 mm using a comma coater. After that, the film was applied so that the film thickness was equivalent to 5 μm, then the polyamic acid solution V3 was applied using a slit die so that the final film thickness including V2 was 38 μm, and dried at 105 ° C. for 25 minutes. After that, it was peeled off from the polyester film to obtain a self-supporting polyamic acid film having a width of 920 mm.
Next, the obtained self-supporting polyamic acid film was heat-treated with a pin tenter at the first stage of 180 ° C. × 5 minutes, the second stage of 220 ° C. × 5 minutes, and the third stage of 495 ° C. × 10 minutes) to imidize the film. The pin gripping portions at both ends were dropped by slits to obtain a long polyimide film F3 (1000 m roll) having a width of 850 mm. The characteristics of the obtained film F3 are shown in Table 1.

<Surface treatment of polyimide film>
The obtained polyimide films F1 to F3 were surface-treated with the surface treatment solutions shown in Tables 2 to 4 and the treatment conditions.

<Example 1>
On the atmospheric pressure plasma-treated substrate thus obtained, the surface-treated surface of the polyimide film 1 obtained in Production Example 1 was subjected to a roll pressure of 8 kgf / cm2 and a roll using a precision sheet-fed bonding machine (SE650nH manufactured by Climb Products Co., Ltd.). A temporary laminated substrate was obtained by laminating a film 10 mm inside from the outer circumference of the glass at a speed of 5 mm / sec. Then, the obtained temporary laminated substrate was placed in a clean oven, heated at 200 ° C. for 1 hour in a nitrogen atmosphere, and then allowed to cool to room temperature to obtain the laminate L1 of the present invention. Table 2 shows the results of evaluating the obtained laminate.
Hereinafter, the laminated body was prepared under the same conditions and evaluated. The results are shown in Tables 2-4.

The laminated plate of the present invention is extremely useful when manufacturing a flexible electronic device using a processing device compatible with a hard substrate such as a glass substrate or a silicon wafer. In particular, according to the present invention, a good adhesive portion and an easy bonding portion are provided. It is extremely useful when the boundary of the peeled portion is clear, the curl of the film after peeling is small, or when a large number of flexible electronic devices are allocated and manufactured in one substrate.

Claims (7)

In a method for producing a laminate in which a substrate made of an inorganic substance treated with a silane coupling agent and a surface-treated polyimide film are overlapped and brought into close contact with each other and bonded to each other by heating.
The surface treatment of the polyimide film is characterized by including a step of contacting with an aqueous surfactant solution containing potassium hydroxide having a temperature of 12 ° C. or higher, 48 ° C. or lower, pH 8.5 or higher and 10.5 or lower for 10 seconds or longer. A method for manufacturing a laminate. The production of the laminate according to claim 1, further comprising a step of reducing the moisture absorption rate of the polyimide film to 0.5% or less by drying at a temperature of 80 ° C. or higher after the surface treatment of the polyimide film. Method. By partially inactivating the surface of the inorganic substance treated with the silane coupling agent, a good adhesive portion having a high adhesive strength of the polyimide film to the substrate and an easily peelable portion having a low adhesive strength are formed. The method for producing a laminate according to claim 1 or 2. The laminate according to any one of claims 1 to 3, wherein the thickness of the silane coupling agent layer formed by the silane coupling agent treatment is 50 nm or less. The laminate according to any one of claims 1 to 4, wherein the area of the inorganic substrate is 1700 square cm or more. The inactivation treatment is a treatment for exposing plasma to the substrate surface by passing the coupling agent-treated substrate between a pair of opposing electrodes in which plasma is generated by an alternating electric field, and the alternating electric field. The method for producing a laminate according to claim 3, wherein the frequency of the laminated body is 8 kHz or more and 300 kHz or less, and the electric field strength is 45 kV / m or more and 240 kV / m or less. The claim is characterized in that the inactivation treatment is a treatment of irradiating a substrate with plasma generated by an alternating electric field having a frequency of 8 kHz or more and 300 kHz or less in atmospheric pressure in a state where the electric field strength is less than 45 kV / m. Item 3. The method for producing a laminate according to Item 3 .