JP5998994B2 - Method for producing polyimide laminate - Google Patents

Description

  The present invention relates to a method for producing a polyimide laminate that is small in warpage and excellent in adhesion between a substrate and a polyimide resin film.

In recent years, polyimide resin has been used favorably when forming a surface protective film or an interlayer insulating film of a semiconductor element because of excellent electrical characteristics, mechanical characteristics, and heat resistance.
However, the linear expansion coefficient of the polyimide resin film is usually 20 ppm / ° C. or more, and is based on the linear expansion coefficient of the metal substrate (usually 20 ppm / ° C. or less) and the linear expansion coefficient of the silicon wafer (about 3 to 4 ppm / ° C.). Is also big. For this reason, when a surface protective film or an interlayer insulating film is formed on these substrates using a polyimide resin, problems such as generation of cracks, disconnection of wiring, and warping of the substrate may occur.

As a method for solving these problems, a method of forming a polyimide resin film having a low linear expansion coefficient by using a polyimide resin having a specific structure is known.
For example, Patent Document 1 describes a photosensitive polyimide precursor obtained by reaction of tetracarboxylic acid or its acid anhydride and diamine, and a polyimide resin film obtained using this photosensitive polyimide precursor. . This document also describes that a polyimide resin film having a small linear expansion coefficient and residual stress can be formed by using a rigid tetracarboxylic acid or acid anhydride thereof and a rigid diamine.

However, even when the polyimide resin described in Patent Document 1 is used, it is difficult to obtain a polyimide resin film having a small linear expansion coefficient when the thickness of the polyimide resin film is increased.
For this reason, when a polyimide resin film is used as an interlayer insulating film, there is a problem that if the thickness is increased in order to increase the insulating property, the laminated body composed of the substrate and the polyimide resin film tends to warp.
Furthermore, when the thickness of the polyimide resin film is increased, there is a problem that the adhesion between the substrate and the polyimide resin film is likely to be lowered.

JP 2004-285129 A

  This invention is made | formed in view of the situation mentioned above, Comprising: It aims at providing the manufacturing method of the polyimide laminated body which is small in curvature and excellent in the adhesiveness between a board | substrate and a polyimide resin film.

  As a result of diligent research to solve the above problems, the present inventor formed a polyimide precursor resin film on a substrate, and then immersed the polyimide precursor resin film in a predetermined solvent, and then the polyimide precursor resin film. It was found that a polyimide laminate having the desired characteristics can be efficiently obtained by processing the first heat treatment, the cooling treatment, and the second heat treatment in this order at a predetermined temperature, and the present invention has been completed. .

  Thus, according to the present invention, the following (1) to (7) polyimide laminate production methods are provided.

(1) A method for producing a polyimide laminate comprising a polyimide resin film formed on a substrate, the method comprising the following steps a to c.
(Step a) On the substrate or on the polyimide precursor resin film already formed on the substrate, at least the polyimide precursor resin and the solvent A are contained, and the content of the solvent A is 46 to 95 weight with respect to the whole solution. % Polyimide precursor resin film-forming liquid is applied, and the resulting coating film is dried until the residual amount of solvent A is 1 to 45% by weight with respect to the entire coating film. Step of forming precursor resin film (step b) Step of immersing the polyimide precursor resin film obtained in step a in solvent B having affinity with solvent A (step c) After step b, polyimide precursor The polyimide precursor is processed in the order of the first heat treatment for heating the body resin film to 130 to 250 ° C., the cooling treatment for cooling to 0 to 120 ° C., and the second heat treatment for heating to 250 to 450 ° C. Polyimide in resin film The precursor resin was closed, forming a polyimide resin film

(2) The method for producing a polyimide laminate according to (1), further comprising the following step d.
(Step d) Step of flattening the surface of the polyimide resin film obtained in step c (3) The step b is a solvent having affinity with the solvent A for the polyimide precursor resin film obtained in step a. The manufacturing method of the polyimide laminated body as described in (1) or (2) which is a process immersed in B at 10-40 degreeC for 1 to 60 minutes.

(4) The method for producing a polyimide laminate according to any one of (1) to (3), wherein the linear expansion coefficient of the polyimide resin film is +1 to +21 ppm / ° C.
(5) The manufacturing method of the polyimide laminated body in any one of (1)-(4) whose film thickness of a polyimide resin film is 15-1000 micrometers.
(6) The manufacturing method of the polyimide laminated body in any one of (1)-(5) whose film thickness of the polyimide precursor resin film obtained at the process a is 15 micrometers or more.
(7) The polyimide laminate according to (1) to (6), wherein the substrate is a single-layer substrate having a linear expansion coefficient of +1 to +21 ppm / ° C., or a composite substrate formed by laminating two or more single-layer substrates. Body manufacturing method.

  According to the method for producing a polyimide laminate of the present invention, it is possible to obtain a polyimide laminate having a small warpage and excellent adhesion between the substrate and the polyimide resin film.

Hereinafter, the manufacturing method of the polyimide laminated body of this invention is demonstrated in detail.
The manufacturing method of the polyimide laminated body of this invention is a manufacturing method of the polyimide laminated body which forms a polyimide resin film on a board | substrate, Comprising: It has the following processes a-c.
(Step a) On the substrate or on the polyimide precursor resin film already formed on the substrate, at least the polyimide precursor resin and the solvent A are contained, and the content of the solvent A is 46 to 95 weight with respect to the whole solution. % Polyimide precursor resin film-forming liquid is applied, and the resulting coating film is dried until the residual amount of solvent A is 1 to 45% by weight with respect to the entire coating film. Step of forming precursor resin film (step b) Step a Step of immersing the obtained polyimide precursor resin film in solvent B having affinity with solvent A (step c) After step b, polyimide precursor By treating the resin film in the order of a first heat treatment for heating to 130 to 250 ° C., a cooling treatment for cooling to 0 to 120 ° C., and a second heat treatment for heating to 250 to 450 ° C., a polyimide precursor resin Before polyimide in the film Body resin by ring closure to form a polyimide resin film

(substrate)
The substrate used in the present invention is not particularly limited as long as it can support a polyimide precursor resin film or a polyimide resin film and is stable under heating conditions when the polyimide precursor resin is closed.
Examples of the substrate include inorganic substrates such as glass substrates, ceramic substrates, and semiconductor substrates, and metal substrates such as stainless steel substrates, aluminum substrates, and copper substrates.

  Examples of the glass substrate include those made of glass materials such as soda lime glass, soda potassium glass, soda aluminum silicate glass, alumino borosilicate glass, alumino borosilicate glass, low expansion glass, and quartz glass.

  Examples of the ceramic substrate include those made of a ceramic material such as alumina, zirconia, mullite, cordierite, steatite, magnesium titanate, calcium titanate, strontium titanate, aluminum nitride, silicon carbide, and silicon nitride.

  As the semiconductor substrate, elemental semiconductor materials such as silicon (Si), germanium (Ge), selenium (Se), tin (Sn), tellurium (Te), SiC, GaN, GaP, GaAs, GaSb, AlP, AlAs, Examples include those made of compound semiconductor materials such as AlSb, InP, InAs, InSb, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, AlGaAs, GaInAs, AlInAs, and AlGaInAs.

  The thickness of the substrate is not particularly specified, but an advantage is usually observed in a thin film substrate of 600 μm or less, preferably 200 μm or less, more preferably 30 to 200 μm.

  In the present invention, it is preferable to use a single layer substrate having a linear expansion coefficient of +1 to +21 ppm / ° C. or a composite substrate in which two or more single layer substrates are stacked as the substrate. By using such a substrate, the difference between the linear expansion coefficient of the polyimide resin film formed thereon is reduced, and thus the warpage of the laminate is reduced.

Examples of the substrate having a linear expansion coefficient include inorganic substrates such as glass substrates, ceramic substrates, and semiconductor substrates, and metal substrates such as stainless steel substrates, aluminum substrates, and copper substrates.
Among them, an inorganic substrate having a linear expansion coefficient of +3 to +17 ppm / ° C. or a single-layer substrate of a metal substrate, or a composite substrate formed by laminating two or more of these single-layer substrates is preferable, a Si substrate, a SiC substrate, a GaN substrate, And a semiconductor substrate selected from GaAs substrates and those having a metal layer (wiring layer) formed on these substrates are more preferred. These substrates may be used as they are, or may be subjected to a surface treatment in order to enhance adhesion with the resin. As the surface treatment, a conventionally known general method can be used. Specific examples include silane coupling agent treatment, aluminum alcoholate treatment, aluminum chelate treatment, and titanate coupling agent treatment. .

(Polyimide resin film)
The manufacturing method of the polyimide laminated body of this invention forms a polyimide resin film on a board | substrate.
As long as the polyimide resin film formed on the substrate is generated by the ring closure reaction (thermal imidation reaction) of the polyimide precursor resin, the type of polyimide precursor resin or polyimide resin. However, a known polyimide resin film can be used.

  As a polyimide precursor resin, what has a repeating unit shown by following formula (1) formed by the polycondensation reaction of tetracarboxylic acid or its acid anhydride, and diamine is mentioned.

In Formula (1), R ¹ is a tetravalent organic group, preferably an organic group having 6 to 30 carbon atoms, more preferably an organic group having 6 to 30 carbon atoms having an aromatic ring. is there. R ² is a divalent organic group, preferably an organic group having 6 to 30 carbon atoms, more preferably an organic group having 6 to 30 carbon atoms having an aromatic ring.

  Examples of the tetracarboxylic acid or its acid anhydride include tetracarboxylic acid represented by the following formula (2) and its acid anhydride.

In formula (2), R ¹ represents the same meaning as described above.

  Examples of the tetracarboxylic acid represented by the formula (2) or an acid anhydride thereof include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, benzene-1,2,3. , 4-tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, naphthalene-2, 3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1 , 2,5,8-tetracarboxylic dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexa Hydronaphthalene-1,2,5 -Tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloro Naphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene -1,4,5,8-tetracarboxylic dianhydride, 1,4,5,8-tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 3,3 ', 4 4'-biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, 2,3,3', 4'-diphenyltetracarboxylic dianhydride, 2,3 ", 4,4" -p-terphenyltetracarboxylic acid 2,2 ", 3,3" -p-terphenyltetracarboxylic dianhydride, 2,3,3 ", 4" -p-terphenyltetracarboxylic dianhydride, 2,2-bis ( 2,3-dicarboxyphenyl) -propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3- Dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3 , 4-Dicarbo Xylphenyl) ethane dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, perylene-4,5,10,11 -Tetracarboxylic dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6, Aromatic tetracarboxylic dianhydrides such as 7-tetracarboxylic dianhydride and phenanthrene-1,2,9,10-tetracarboxylic dianhydride and their water additives; cyclopentane-1,2,3 4-tetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, bicyclo [2,2,2] oct-7-en-2-exo, 3-exo, 5-exo, 6-exotetracar Acid 2,3: 5,6-dianhydride, bicyclo [2,2,1] heptane-2-exo, 3-exo, 5-exo, 6-exotetracarboxylic acid 2,3: 5,6- Alicyclic acid dianhydrides such as dianhydrides; pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2 , 3,4,5-tetracarboxylic dianhydride and the like heterocyclic derivative dianhydrides; and tetracarboxylic acids corresponding to these.

  Examples of the diamine include compounds represented by the following formula (3).

In formula (3), R ² represents the same meaning as described above.

  As the diamine represented by the formula (3), 4,4′-diaminobenzanilide, 4,4′-diamino-2,2′-ditrifluoromethylbiphenyl, 2,2′-di (p-aminophenyl)- 5,5′-bisbenzoxazole, 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole, 2,2′-di (p-aminophenyl) -5,5′-bis Benzimidazole, 3,6- (4-aminophenyl) pyridazine, 4,4′-diaminobenzanilide, p-phenylenediamine (PPDA), 4,4′-diaminobiphenyl, m-phenylenediamine, 1-isopropyl-2 , 4-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 4,4 ′ Diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, benzidine, 4,4 ″ -diamino -P-terphenyl, 3,3 "-diamino-p-terphenyl, bis (p-aminocyclohexyl) methene, bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl- δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6- Diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xy Examples include len-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, and p-xylylenediamine.

  The polyimide precursor resin can be obtained by a polycondensation reaction between the tetracarboxylic acid or its acid anhydride and a diamine. Such a reaction can be carried out in a polar organic solvent such as dimethylacetamide or N-methyl-2-pyrrolidone. The reaction conditions are not particularly limited, but are usually 0.5 to 50 hours, preferably 5 to 30 hours under ice cooling or room temperature.

The weight average molecular weight of the polyimide precursor resin is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000.
The molecular weight distribution of the polyimide precursor resin is preferably 1.3 to 3, more preferably 1.5 to 2.5.
In addition, a weight average molecular weight and molecular weight distribution are the polystyrene conversion values obtained by the gel permeation chromatography method which uses N, N- dimethylacetamide as a solvent.

  The polyimide precursor resin may have an actinic functional group at the terminal. Examples of the polyimide precursor resin having an actinic radiation functional group include those described in JP-A No. 11-282157. Moreover, the terminal may have a functional group expected to suppress the release of copper ions such as a tetrazole group and an imidazole group. Examples thereof include those described in JP-A-10-260531.

  In this invention, the polyimide resin film formed on a board | substrate contains the polyimide resin produced | generated by ring-closing the above polyimide precursor resin.

The manufacturing method of the polyimide laminated body of this invention is a method of manufacturing a polyimide resin film on a board | substrate, Comprising: It has the said process a-process c, It is characterized by the above-mentioned.
Hereinafter, the manufacturing method of the polyimide laminated body of this invention is demonstrated in detail in order of a process.

1. Step a
The process a contains at least the polyimide precursor resin and the solvent A on the substrate or the polyimide precursor resin film already formed on the substrate, and the content of the solvent A is 46 to 95 weight with respect to the entire solution. % Polyimide precursor resin film-forming liquid is applied, and the resulting coating film is dried until the residual amount of solvent A is 1 to 45% by weight with respect to the entire coating film. This is a step of forming a precursor resin film.

The above-mentioned “polyimide precursor resin film already formed on the substrate” means that the “residual amount of solvent A is a coating film already formed on the substrate by performing step a of the present invention at least once. It means 1 to 45% by weight of the polyimide precursor resin film ”.
Thus, the polyimide precursor resin film formed in step a is a polyimide precursor resin formed by applying the polyimide precursor resin film-forming liquid and drying the obtained coating film once each. It may be a film, or may be a polyimide precursor resin film formed by repeating these operations two or more times. By repeating these operations twice or more, a polyimide precursor resin film having a large thickness and a uniform film thickness can be efficiently formed.

The polyimide precursor resin forming liquid to be used contains at least the polyimide precursor resin and the solvent A, and the content of the solvent A is 46 to 95% by weight, preferably 50 to 90% by weight based on the entire solution. When the content of the solvent A is within the above range, a polyimide precursor resin film having a predetermined solvent residual amount can be easily formed.
In this specification, the solvent contained in the polyimide precursor resin film forming liquid is referred to as “solvent A”.

As a polyimide precursor resin, what was demonstrated previously can be used.
The content of the polyimide precursor resin in the polyimide precursor resin film forming liquid is preferably 5 to 54% by weight, more preferably 10 to 50% by weight.

The solvent A is not particularly limited as long as it dissolves or disperses the polyimide precursor resin and other components.
As the solvent A, a polar solvent is preferable. For example, water; amide solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, hexamethylphosphoric triamide; sulfur-containing systems such as dimethyl sulfoxide and sulfolane Solvent; and the like. Among these, amide solvents and sulfur-containing solvents are more preferable, amide solvents are more preferable, and N-methyl-2-pyrrolidone is particularly preferable. These solvents can be used alone or in combination of two or more.

  In the present invention, the reaction solution after the polycondensation reaction of the above tetracarboxylic acid or its acid anhydride and diamine can be used as it is as a polyimide precursor resin film forming solution. Therefore, in this case, the solvent used in the polycondensation reaction is the solvent A.

As described above, the solvent A dissolves or disperses the polyimide precursor resin and other components. Moreover, when using the reaction liquid after a polycondensation reaction as it is as a polyimide precursor resin film formation liquid, the solvent A raises a polycondensation reaction efficiently.
Since these characteristics are required, a polar solvent is preferably used as the solvent A.

  However, since the polar solvent preferably used normally as the solvent A has a high boiling point (usually 150 ° C. or higher), the solvent A can be efficiently removed from the coating film obtained by applying the polyimide precursor resin film-forming liquid. Was difficult. When the solvent A remains in the polyimide resin film, there is a problem that the linear expansion coefficient of the polyimide resin film increases.

In particular, when a polyimide resin film having a large film thickness such as an insulating film is formed, it is more difficult to remove the solvent A. Therefore, conventionally, a polyimide resin film having a large film thickness and a small linear expansion coefficient is used. It was hard to get.
The method for producing a polyimide laminate of the present invention solves this problem. As will be described later, by performing step b after step a, a polyimide resin having a large film thickness and a small linear expansion coefficient is obtained. A film can be formed efficiently.

The polyimide precursor resin forming liquid may contain an inorganic heat dissipating filler. By using a polyimide precursor resin forming liquid containing an inorganic heat dissipating filler, a polyimide laminate having a polyimide resin film with better thermal conductivity can be obtained.
This polyimide laminate is suitable for use as a semiconductor chip material because it can efficiently release the heat generated when the semiconductor is driven and contributes to improving the reliability of the semiconductor.

The inorganic heat dissipating filler is not particularly limited as long as it has heat dissipating properties, and known ones can be used.
Examples of the inorganic heat dissipation filler include silicon oxide, alumina, aluminum nitride, silicon nitride, and boron nitride. A heat radiation filler can be used individually by 1 type or in combination of 2 or more types.

The shape of the inorganic heat radiation filler to be used is not particularly limited. For example, a spherical shape, a plate shape, a needle shape, or the like can be used. Especially, since it is excellent in heat dissipation, a plate shape or a needle shape is preferable.
The inorganic heat dissipating filler preferably has an average particle diameter of 0.1 to 50 μm, and more preferably 0.5 to 20 μm.
The average particle size of the inorganic heat dissipating filler is a value measured by a laser diffraction / scattering method.

  When the inorganic heat dissipation filler is contained, the content thereof is preferably 15 to 60% by weight, more preferably 20 to 60% by weight, and particularly preferably 30 to 45% by weight with respect to the polyimide precursor resin. When there is too much content of an inorganic heat radiation filler, although heat dissipation will improve, there exists a possibility that board | substrate adhesiveness may fall significantly or the mechanical characteristic of a polyimide resin film may fall.

  The manufacturing method of this invention which has a solvent immersion process is especially useful when forming a polyimide resin film using the polyimide precursor resin formation liquid containing an inorganic thermal radiation filler. That is, according to the production method of the present invention, the polyimide resin chain is oriented in a certain direction, and at the same time, the inorganic heat dissipating filler is also oriented in accordance with the orientation direction of the polyimide resin chain. A resin film is easily obtained.

The polyimide precursor resin film-forming liquid may contain various additives.
Examples of the additive include an adhesion assistant, a leveling agent, a polymerization inhibitor, a photopolymerization initiator, and a photosensitive assistant.

  The method for applying the polyimide precursor resin film-forming liquid on the substrate or the polyimide precursor resin film already formed on the substrate is not particularly limited, and a conventionally known method can be used. Examples of the coating method include spin coating, dip coating, roll coating, curtain coating, die coating, and slit coating.

In this invention, after apply | coating a polyimide precursor resin film formation liquid, the residual amount of the solvent A is 1-45 weight% with respect to the whole coating film, Preferably it is 3-40 weight% from the whole coating film. Preferably it is dried to 5 to 35% by weight. When the residual amount of the solvent A is less than 1% by weight, the removal of the solvent in the next step b becomes worse. On the other hand, when the residual amount of the solvent A exceeds 45% by weight, the finally obtained polyimide resin film does not become a uniform film.
The drying temperature is usually 50 to 130 ° C., preferably 60 to 120 ° C., more preferably 70 to 110 ° C., and the drying time is usually 1 to 60 minutes, preferably 1 to 50 minutes, more preferably 1 to 40. Minutes.

The film thickness of the polyimide precursor resin film obtained in step a is usually 15 μm or more, preferably 15 to 1000 μm, more preferably 15 to 800 μm. By being in this range, a polyimide resin film having a sufficient thickness can be formed.
As described above, the polyimide precursor resin having a large thickness and a uniform film thickness is obtained by repeating the coating of the polyimide precursor resin film forming liquid and the drying of the obtained coating film twice or more. A film can be formed efficiently.

2. Step b
Step b is a step of immersing the polyimide precursor resin film obtained in step a in the solvent B having affinity with the solvent A.
In this specification, the solvent used in step b is referred to as “solvent B”.
By performing the step b, the solvent A can be efficiently removed from the polyimide precursor resin film. For this reason, even if the film thickness is large, a polyimide resin film having a small linear expansion coefficient can be easily formed, and a polyimide laminate having a small warpage can be obtained.

Moreover, while performing said process b, said effect is acquired, On the other hand, the adhesiveness between a board | substrate and a polyimide resin film may fall.
In the method for producing a polyimide laminate of the present invention, as will be described later, by performing step c after step b, this problem of lowering adhesion can be solved.

The solvent B is a solvent having affinity with the solvent A. The solvent B is preferably one that is uniformly mixed with the same volume of the solvent A at 25 ° C. By immersing the polyimide precursor resin film in the solvent B having such characteristics, the solvent A remaining in the polyimide precursor resin film can be efficiently removed.
Moreover, since the solvent B can be efficiently removed by drying in the next step c, the solvent B is preferably a solvent having a relatively low boiling point. The boiling point of the solvent B is preferably 120 ° C. or lower, more preferably 110 ° C. or lower. The lower limit of the boiling point of the solvent B is not particularly limited as long as the immersion treatment can be performed at around room temperature.

When an amide solvent or a sulfur-containing solvent is used as the solvent A, the solvent B is preferably a polar solvent other than the amide solvent or the sulfur-containing solvent. Examples of such polar solvents include water; alcohol solvents such as methanol and ethanol; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone;
These polar solvents can be used alone or in combination of two or more. Among these, as the solvent B, a mixed solvent of two or more selected from water, acetone and methanol is preferable, and a mixed solvent of water and acetone is more preferable. In the mixed solvent of water and acetone, the mixing ratio (weight ratio of water: acetone) is usually 1:99 to 99: 1, preferably 5:95 to 95: 5.

The temperature at which the polyimide precursor resin film is immersed in the solvent B is usually 10 to 40 ° C, preferably 15 to 35 ° C. Since the immersion temperature is within this range, the evaporation of the solvent B can be suppressed, so that the operation can be performed safely. Moreover, when using 2 or more types of solvent B, since the change of a mixing ratio can be suppressed by using the said temperature conditions, the solvent A can be removed from a polyimide precursor resin film with sufficient reproducibility.
The time for immersing the polyimide precursor resin film in the solvent B is usually 1 to 60 minutes, preferably 1 to 45 minutes, more preferably 1 to 30 minutes. When the immersion time is within this range, the solvent A can be efficiently removed from the polyimide precursor resin film.

  In step b, at least the polyimide precursor resin film may be immersed in the solvent B. Therefore, the polyimide precursor resin film may be immersed in the solvent B together with the substrate, or the polyimide precursor resin film may be immersed in the solvent B in a state where a part of the substrate is not in contact with the solvent B.

3. Process c
Step c is a first heat treatment for heating the polyimide precursor resin film to 130 to 250 ° C. after the step b, a cooling treatment for cooling to 0 to 120 ° C., and a second heat treatment for heating to 250 to 450 ° C. In this step, the polyimide precursor resin in the polyimide precursor resin film is closed to form a polyimide resin film.

  In step c, by treating the polyimide precursor resin film in the order of the first heat treatment, the cooling treatment, and the second heat treatment, a polyimide resin film having excellent adhesion to the substrate can be formed.

The heating temperature in 1st heat processing is 130-250 degreeC, Preferably it is 150-240 degreeC, More preferably, it is 170-230 degreeC. When the heating temperature is lower than 130 ° C., it becomes difficult to obtain a polyimide resin film having excellent adhesion to the substrate, and when it exceeds 250 ° C., the polyimide resin film may swell.
The heating time is not particularly limited, but is usually 1 to 120 minutes, preferably 1 to 90 minutes, and more preferably 1 to 60 minutes. When the heating time is within this range, a polyimide resin film having excellent adhesion to the substrate can be obtained. The heating method is not particularly limited, and a conventionally known method can be used.

The cooling temperature in the cooling treatment is 0 to 120 ° C, preferably 10 to 110 ° C, more preferably 25 to 100 ° C. When the cooling temperature is within this range, a polyimide resin film having excellent adhesion to the substrate can be obtained.
The cooling process only needs to be able to cool to a predetermined temperature, and the cooling time can be appropriately determined.
There is no particular limitation on the cooling method. For example, it can be cooled by air drying.

The heating temperature in the second heat treatment is 250 to 450 ° C, preferably 300 to 450 ° C, more preferably 350 to 450 ° C. When the heating temperature is lower than 250 ° C., imidization tends to be incomplete, and when it exceeds 450 ° C., the polyimide resin is easily deteriorated because it is heated too much.
The heating time is not particularly limited, but is usually 1 to 120 minutes, preferably 1 to 90 minutes, and more preferably 1 to 60 minutes. By being in this range, a polyimide resin film having excellent adhesion to the substrate can be obtained. The heating method is not particularly limited, and a conventionally known method can be used. For example, the temperature may be increased stepwise, such as heating at 250 ° C. for 30 minutes and then heating at 450 ° C. for 30 minutes.

  By performing step c, the polyimide precursor resin in the polyimide precursor resin film is closed, and a polyimide resin is formed.

The linear expansion coefficient of the formed polyimide resin film is preferably +1 to +21 ppm / ° C., more preferably +3 to +20 ppm / ° C. If the linear expansion coefficient is within the above range, it is close to the linear expansion coefficient of a general substrate. Therefore, when manufacturing a semiconductor chip or the like using the polyimide laminate obtained in the present invention, or when using it In addition, problems such as generation of cracks due to heating and heat generation, disconnection of wiring, and warping of the substrate are less likely to occur.
The linear expansion coefficient can be measured by a conventionally known measuring apparatus and measuring method.

The film thickness of the formed polyimide resin film is usually 15 to 1000 μm, preferably 15 to 800 μm, more preferably 15 to 500 μm. When the film thickness is 15 μm or more, a highly insulating polyimide resin film can be formed.
In order to increase the film thickness of the polyimide resin film, in step a as described above, the polyimide precursor resin film is repeatedly applied by applying the polyimide precursor resin film forming liquid and drying the obtained coating film. The film thickness can be increased.

4). Other Steps In the method for producing a polyimide laminate of the present invention, after step c is completed, the following step d may be performed as necessary.
(Step d) Step of flattening the surface of the polyimide resin film obtained in step c

Step d is performed as a pretreatment when a wiring is formed on the polyimide resin film or as a cueing process when a metal post (conductive via) is embedded in the polyimide resin film.
The surface of the polyimide resin film can be flattened by a conventionally known method such as cutting, grinding, or polishing.

The polyimide resin film formed by the production method of the present invention has a small coefficient of linear expansion, and is almost the same as the coefficient of linear expansion of a commonly used substrate. Therefore, since the polyimide laminate obtained by the production method of the present invention hardly warps, the surface of the polyimide resin film can be flattened cleanly.
For example, in the polyimide laminate obtained by the production method of the present invention, the surface roughness (Rz) of the polyimide resin film is usually 3 μm or less, preferably 2 μm or less, more preferably by cutting the surface of the polyimide resin film. Can be 1 μm or less.

  Thus, the surface roughness of this polyimide resin film can be easily made small by carrying out the planarization process of the polyimide resin film of the polyimide laminated body obtained by the manufacturing method of this invention. When a metal layer such as a wiring layer is formed on such a polyimide resin film, the adhesion between the metal layer and the polyimide resin film is excellent.

According to the method for producing a polyimide laminate of the present invention, a polyimide resin film having a large film thickness, a small linear expansion coefficient, and excellent adhesion to the substrate is formed on the substrate. Therefore, this polyimide resin film is suitable as an interlayer insulating film.
The polyimide laminate obtained by the present invention has the above polyimide resin film on a substrate, and is suitably used as a semiconductor chip material.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to these Examples.

(Production Example 1) Preparation of polyimide precursor resin film forming liquid 1 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride 9.0 g (0.03 mol), 2,2′-di (p -Aminophenyl) -6,6′-bisbenzoxazole 12.3 g (0.029 mol) and 5-aminotetrazole 0.2 g (0.002 mol) were added to 113 g of N-methyl-2-pyrrolidone (NMP). It melt | dissolved and stirred for 24 hours at room temperature, and the polymerization reaction was performed.
In the following examples, this polymerization reaction solution was used as the polyimide precursor resin film forming solution 1 as it was. The NMP content in the entire solution was 84% by weight. The concentrations of the polyimide precursor resin were 16% by weight, Mw = 68000, and Mw / Mn = 1.9.
In addition, a weight average molecular weight and molecular weight distribution are the polystyrene conversion values obtained by the gel permeation chromatography method which uses tetrahydrofuran as a solvent.

(Production Example 2) Preparation of Polyimide Precursor Resin Film Formation Liquid 2 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride 11.0 g (0.04 mol) and 1,4-diaminobenzene 3 0.9 g (0.04 mol) was dissolved in 78 g of N-methyl-2-pyrrolidone (NMP) and stirred at room temperature for 24 hours to carry out a polymerization reaction.
In the following Examples, this polymerization reaction liquid was used as the polyimide precursor resin film forming liquid 2 as it was. The NMP content in the entire solution was 82% by weight. The concentrations of the polyimide precursor resin were 18% by weight, Mw = 48000, and Mw / Mn = 1.9.

(Production Example 3) Preparation of Substrate Surface Treatment Solution In a 100 ml clean bottle, put 28.7 g of ethanol, 0.3 g of 3-aminopropyltriethoxysilane (manufactured by AMAX Co., Silaace S330), 1.0 g of ion-exchanged water for 10 minutes. The substrate surface treatment solution was prepared by stirring.

(Production Example 4) Surface Treatment of Silicon Wafer After setting a silicon wafer having a thickness of 525 μm (linear expansion coefficient 4 ppm / ° C.) on the base of the spin coater, 2 ml of the substrate surface treatment solution prepared in Production Example 3 was applied to the entire surface of the silicon wafer. It was hung with a polyethylene dropper so as to spread. Next, the silicon wafer was rotated at 500 rpm for 10 seconds and 1500 rpm for 20 seconds to remove excess substrate surface treatment solution. Thereafter, the silicon wafer was dried by heating on a hot plate at 130 ° C. for 2 minutes and then air-cooled.

(Production Example 5) Preparation of Polyimide Precursor Resin Film Forming Liquid 3 (Inorganic Heat Dissipation Filler-Containing Polyimide Precursor Resin Film Forming Liquid) Toluene 200 g and boron nitride (BN-GP: average particle size 8 μm, manufactured by Denki Kagaku Kogyo) 30 g Was added to obtain a suspension. While this suspension was stirred at room temperature under a nitrogen atmosphere, a toluene solution of a silane coupling agent (S-330: manufactured by Chisso Corporation) was added to the suspension (silane coupling agent 0.6 g / toluene 50 g). Then, the surface treatment of boron nitride was carried out by continuing stirring at room temperature for 1 hour and at 120 ° C. for 1 hour. After adding 200 g of dehydrated N-methylpyrrolidone (NMP) to the obtained reaction solution, the temperature was raised to 180 ° C. under a nitrogen stream, and toluene was distilled off. After cooling this to room temperature, NMP was added to obtain a total amount of 200 g of NMP dispersion (inorganic heat dissipating filler dispersion 1) containing 30 g of boron nitride (BN-GP).

Inorganic heat dissipation filler dispersion 1 42.13 g, 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole 12.051 g (0.0288 mol), 5-aminotetrazole 0.204 g (0 .0024 mol), 19.53 g of NMP, and 55.34 g of N, N-dimethylacetamide (DMAc) were mixed under a nitrogen atmosphere. Next, while stirring this mixture under ice cooling, 8.827 g (0.03 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added in powder form, The polymerization reaction was carried out by continuing stirring for 2 hours under cooling and 22 hours at room temperature (25 ° C.).
In the following examples, this polymerization reaction liquid was used as the polyimide precursor resin film forming liquid 3 as it was. The polyimide precursor resin film forming liquid 3 was a cream having a viscosity of 60 poise. The content of boron nitride was 30% by weight with respect to the polyimide precursor resin, and the tetrazole molecular terminal modification rate of the polyimide precursor resin was 8 mol%.

[Example 1]
(Formation of polyimide precursor resin film)
The polyimide precursor resin film forming liquid 1 prepared in Production Example 1 was applied onto the silicon wafer subjected to the surface treatment in Production Example 4 by spin coating (rotated at 500 rpm for 10 seconds and 1500 rpm for 30 seconds).
Thereafter, this coated silicon wafer was heated on a hot plate at 90 ° C. for 6 minutes to remove NMP in the coated film, and then air-cooled. The residual amount of NMP in the formed polyimide precursor resin film was 38% by weight.
The residual amount of NMP in the polyimide precursor resin film is as follows: the weight of the silicon wafer (9.7 g), the weight of the silicon wafer after applying the polyimide precursor resin solution (13.2 g), and 90 ° C. for 6 minutes. It calculated from the weight (10.6 g) of the silicon wafer after heating and the polyimide precursor resin concentration (16 wt%).

(Immersion of polyimide precursor resin film)
Subsequently, the silicon wafer with a polyimide precursor resin film was immersed in a mixed solvent of water and acetone (water: acetone weight ratio = 7: 3) at 25 ° C. for 20 minutes. After the immersion treatment, the surface of the polyimide precursor resin film-coated silicon wafer was dried under a nitrogen stream.

(Thermal imidization)
Next, the silicon wafer with the polyimide precursor resin film is heated at 200 ° C. for 60 minutes in a N ₂ atmosphere using a thermostat (first heat treatment), and then the silicon wafer is taken out from the thermostat to 25 ° C. The silicon wafer after air cooling (cooling treatment) and then air cooling is heated according to the following temperature program under a N ₂ atmosphere using a thermostat (second heat treatment) to obtain a silicon wafer 1 with a polyimide resin film. It was.
(Temperature program in the second heat treatment)
1: 60 ° C. for 60 minutes, 2: Temperature rise to 150 ° C. at 5 ° C./min, 3: 150 ° C. for 60 minutes, 4: Temperature rise to 400 ° C. at 5 ° / min, 5: 400 ° C. for 60 minutes, 6: Cool to room temperature

(Flattening)
Next, the surface of the polyimide resin film of the polyimide resin film-coated silicon wafer 1 was cut using a surface planar (DFS 8910, manufactured by Disco Corporation).

[Example 2]
In the formation process of the polyimide precursor resin film, it was carried out except that the polyimide precursor resin film forming liquid 2 prepared in Production Example 2 was used instead of the polyimide precursor resin film forming liquid 1 prepared in Production Example 1. A silicon wafer 2 with a polyimide resin film was obtained in the same manner as in Example 1.

[Comparative Example 1]
In the thermal imidization step, a silicon wafer with a polyimide resin film is formed by the same method as in Example 1 except that the first heat treatment and the cooling treatment are not performed and the thermal imidization is performed only under the heating conditions of the second heat treatment. 3 was obtained.

[Comparative Example 2]
The silicon wafer 4 with a polyimide resin film was formed by the same method as in Comparative Example 1 except that the thermal imidization process was performed subsequent to the polyimide precursor resin film formation process without performing the immersion treatment of the polyimide precursor resin film. Obtained.

[Comparative Example 3]
A silicon wafer 5 with a polyimide resin film was formed in the same manner as in Example 1 except that the thermal imidization process was performed subsequent to the polyimide precursor resin film formation process without performing the immersion treatment of the polyimide precursor resin film. Obtained.

  The following tests were performed using silicon wafers 1 to 5 with polyimide resin films obtained in Examples 1 and 2 and Comparative Examples 1 to 3.

1. Adhesiveness between polyimide resin film and substrate A silicon wafer with a polyimide resin film after cutting was cut into 1 cm square, and the polyimide resin film side was surface-treated by an argon reverse sputtering method. Next, a measurement sample was prepared by bonding an aluminum stud pin with an epoxy adhesive to the polyimide resin film after the surface treatment.
Using a thin film adhesion strength measuring instrument (Quad Group, Romulus), the adhesion force of the measurement sample produced by the above method was measured and judged according to the following criteria.
○ ... 30 MPa or more Δ ... 10 MPa or more and less than 30 MPa × ... less than 10 MPa Evaluation results are shown in Table 1.

2. Surface roughness (Rz) of polyimide resin film
The surface shape of the silicon wafer with a polyimide resin film after the flattening process was measured using a stylus type surface shape measuring instrument (Dektak 150, manufactured by ULVAC), and the surface roughness (Rz) was calculated.
The measurement results are summarized in Table 1.

3. Adhesiveness between polyimide resin film and upper surface metal layer A metal layer was formed on the surface of the polyimide resin film after the planarization using a sputtering apparatus (I-miller, manufactured by Shibaura Mechatronics). Next, 11 pieces were cut from the surface of the metal layer in the vertical direction and the horizontal direction (intersection angle 90 degrees) at 1 mm intervals to prepare test pieces. Using this test piece, a cross-cut tape test was conducted, and the adhesion with the upper metal layer was evaluated according to the following criteria.
If the surface of the polyimide resin film is rough, there is a difference in the adhesion between the polyimide resin layer and the upper metal layer depending on the location. The uniformity of the sheath can be evaluated.
○ ・ ・ ・ No peeling point
Δ: 1-50 peeled
X: The peeled portion is 51 to 100
The evaluation results are summarized in Table 1.

4). Linear expansion coefficient of polyimide resin film A silicon wafer with a polyimide resin film before flattening was immersed in a 50% hydrofluoric acid solution for 5 minutes to peel off the polyimide resin film. The polyimide resin film was washed with running water and then vacuum dried at 130 ° C. for 3 hours. The polyimide resin film after drying was cut into 20 mm × 4 mm to prepare a test piece.
Using a thermomechanical analyzer (EXSTAR TMA / SS7100, manufactured by SII Nano Technology), the linear expansion coefficient of the test piece was measured twice in the range of 30 to 300 ° C. at a rate of temperature increase of 5 ° C./min. The average linear expansion coefficient (ppm / ° C.) of 80 to 280 ° C. of the second round was taken as the linear expansion coefficient of the polyimide resin film.
The measurement results are summarized in Table 1.

5. Film thickness of polyimide resin film A part of the polyimide resin film of the silicon wafer with the polyimide resin film after the flattening process was shaved to expose the silicon wafer. Using a stylus type surface shape measuring instrument (ULVAC, Dektak 150), the surface shape of the silicon wafer with the polyimide resin film is measured, and the difference between the portion where the polyimide resin film is present and the portion where the silicon wafer is exposed, It was set as the film thickness of the polyimide resin film.
The measurement results are summarized in Table 1.

The following can be seen from Table 1.
The polyimide resin films obtained in Examples 1 and 2 have a low coefficient of linear expansion and excellent adhesion to the substrate.
On the other hand, in Comparative Example 1, as a result of not performing the first heat treatment and the second heat treatment in the thermal imidization step (step c), the obtained polyimide resin film is inferior in adhesion to the substrate.
Comparative Example 2 does not perform the polyimide precursor resin film immersion step (step b), and does not perform the first heat treatment and the second heat treatment in the thermal imidization step (step c), resulting in a large linear expansion coefficient. In addition, the adhesion to the substrate is poor.
In Comparative Example 3, as a result of not performing the immersion process (process b) of the polyimide precursor resin film, the linear expansion coefficient is large.

Example 3
In Example 1, instead of the polyimide precursor resin forming liquid 1, an inorganic material was formed on the silicon wafer in the same manner as in Example 1 except that the polyimide precursor resin forming liquid 3 obtained in Production Example 5 was used. A polyimide resin film containing a heat dissipating filler was formed.
About this polyimide resin film, the adhesiveness of a polyimide resin film and a board | substrate, the linear expansion coefficient, and the film thickness were investigated by the method similar to the above. The results are shown in Table 2.

[Comparative Example 4]
In Example 3, the immersion treatment of the polyimide precursor resin film was not performed, and the thermal imidization process was performed subsequent to the polyimide precursor resin film formation process. In addition, an inorganic heat dissipating filler-containing polyimide resin film was formed.
About this polyimide resin film, the adhesiveness of a polyimide resin film and a board | substrate, the linear expansion coefficient, and the film thickness were investigated by the method similar to the above. The results are shown in Table 2.

Table 2 shows the following.
In Example 3, a polyimide resin film containing an inorganic heat dissipating filler and having excellent substrate adhesion and a low linear expansion coefficient was obtained.
On the other hand, the polyimide resin film obtained in Comparative Example 4 is inferior in substrate adhesion and does not have a sufficiently low linear expansion coefficient.

Claims (7)

A method for producing a polyimide laminate, which comprises forming a polyimide resin film on a substrate, comprising the following steps a to c.
(Step a) On the substrate or on the polyimide precursor resin film already formed on the substrate, at least the polyimide precursor resin and a polar solvent (solvent A) having a boiling point of 150 ° C. or higher are contained. A polyimide precursor resin film-forming solution having a content of 46 to 95% by weight based on the entire solution is applied, and the resulting coating film has a residual amount of solvent A of 1 to 45% by weight based on the entire coating film. The polyimide precursor resin film obtained in the step (step b) step a of forming the polyimide precursor resin film on the substrate is dried to a boiling point having an affinity for the solvent A of 120 ° C. or lower. After the step of immersing in the solvent (solvent B) (step c) and step b, the polyimide precursor resin film is heated to 130 to 250 ° C., cooled to 0 to 120 ° C., and 250 Second heating to heat to ~ 450 ° C By processing in the order of sense, by ring closure of the polyimide precursor resin of the polyimide precursor resin film, forming a polyimide resin film Furthermore, the manufacturing method of the polyimide laminated body of Claim 1 which has the following processes d.
(Step d) Step of flattening the surface of the polyimide resin film obtained in step c   The step b is a step of immersing the polyimide precursor resin film obtained in the step a in a solvent B having an affinity for the solvent A at 10 to 40 ° C. for 1 to 60 minutes. Or the manufacturing method of the polyimide laminated body of 2.   The manufacturing method of the polyimide laminated body in any one of Claims 1-3 whose linear expansion coefficient of a polyimide resin film is + 1- + 21 ppm / degrees C.   The manufacturing method of the polyimide laminated body in any one of Claims 1-4 whose film thickness of a polyimide resin film is 15-1000 micrometers.   The manufacturing method of the polyimide laminated body in any one of Claims 1-5 whose film thickness of the polyimide precursor resin film obtained at the process a is 15 micrometers or more.   The method for producing a polyimide laminate according to claim 1, wherein the substrate is a single layer substrate having a linear expansion coefficient of +1 to +21 ppm / ° C., or a composite substrate formed by laminating two or more single layer substrates.