JP2008195892A - Photosensitive polyimide composition, preparation method of soluble polyimide resin and preparation method of photosensitive polyimide composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive polyimide composition which is capable of forming a protective film that hardly deteriorates in a gold plating process and exerts a sufficient adhesion to a copper foil, retains a developability equivalent to those in conventional techniques and hardly causes problems such as residues, a preparation method of a soluble polyimide resin used as a component thereof, and a preparation method of the photosensitive polyimide composition. <P>SOLUTION: The photosensitive polyimide composition contains the soluble polyimide resin and a positive sensitizer, provided that the soluble polyimide resin is a condensation product of an aromatic tetracarboxylic acid dianhydride and a diamine, and the diamine comprises a silicone diamine and a diamine having a hydroxyl group. The weight average molecular weight of the soluble polyimide resin is 20,000-50,000 and exerts a unimodal molecular weight distribution with a variance of ≤2.0. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photosensitive polyimide composition used as a protective film of a flexible printed wiring board, a method for producing a soluble polyimide resin used as a component of the photosensitive polyimide composition, and production of the photosensitive polyimide composition. It is about the method.

  In recent years, with the miniaturization and weight reduction of electronic devices, miniaturization of devices and wiring has progressed, and an insulating protective film (hereinafter simply referred to as “protective film”) of a flexible printed wiring board (hereinafter referred to as FPC). The method using a photosensitive resin composition has been adopted for the formation. In this method, a photosensitive resin composition is applied to an FPC substrate on which wirings, elements, etc. are formed to form a coating film, and then only a predetermined portion is exposed and developed through a mask etc. Remove the part of the coating film that needs to be exposed.

  As such a photosensitive resin composition, a negative photosensitive resin composition called a solder resist (for example, acrylic-epoxy system) is widely used. However, since these have a structure in which the remaining film portion is cross-linked and hardened, it has the disadvantage that it is hard and brittle and does not have sufficient flexibility, so it is used only in a fine pattern portion in combination with a conventional coverlay. . Therefore, recently, a protective film having flexibility and excellent heat resistance has been desired as an alternative to coverlay, and a positive composition comprising a solvent-soluble resin (soluble resin) and a positive photosensitive agent has been proposed. Yes. Moreover, use of the soluble polyimide resin which provided the solubility to the polyimide resin excellent in heat resistance as a soluble resin is also proposed.

  As the soluble polyimide resin, a soluble polyimide resin synthesized using a diamine having a hydroxyl group has been proposed in Japanese Patent No. 2935994 (Patent Document 1), Japanese Patent Application Laid-Open No. 10-224017 (Patent Document 2), and the like. The polyimide resin is originally insoluble in a solvent, but is soluble and alkali developable by using a flexible monomer component and containing a diamine having a hydroxyl group in a certain ratio or more.

  Examples of the diamine having a hydroxyl group include compounds represented by the following structural formula.

By adding a silicone diamine to the diamine component used for the synthesis of the soluble polyimide resin, the flame retardance of the protective film, the adhesiveness with copper constituting the wiring, the flexibility, and the like can be improved. Therefore, a photosensitive polyimide composition comprising a soluble polyimide resin synthesized using a diamine component containing both a diamine having a hydroxyl group and a silicone diamine and a positive photosensitive agent has been proposed. (WO99 / 19771 Publication, Patent Document 3)
Japanese Patent No. 2935994 Japanese Patent Laid-Open No. 10-2224017 WO99 / 19771 publication

  However, when forming an FPC protective film using a conventional photosensitive polyimide composition, there is a problem that it is difficult to achieve both developability and plating resistance. That is, if a residue (remaining omission) occurs in the exposed portion, the pad portion and the connecting portion are poorly exposed, resulting in a poor electrical connection with the outside. Development is necessary to completely remove the film. However, in this case, the surface of the coating film (protective film) in the unexposed area is likely to be deteriorated in the gold plating process performed for the formation of the developer or the connection part, and new defects such as spot discoloration occur. Likely to happen.

  Furthermore, the protective film formed using the conventional photosensitive polyimide composition has insufficient adhesive force with the copper foil constituting the FPC, so that a developer or a plating solution soaks from the opening, There was a risk of causing defects.

  The present invention is not easily deteriorated even in the gold plating process, in particular, it is difficult to cause spot defects and can form a protective film having sufficient adhesion to copper foil, and developability similar to that of conventional photosensitive polyimide compositions. It is an object of the present invention to provide a photosensitive polyimide composition and a method for producing the same that are less susceptible to problems such as residues.

  The present inventor has found that the soluble polyimide resin used as the base resin of the conventional photosensitive polyimide composition has a broad molecular weight distribution (dispersion), and has a two-peak distribution having peaks in the low molecular weight region and the high molecular weight region, It was found that it contains a lot of low molecular weight components. Since the high molecular weight component is hardly soluble in the solvent and the low molecular weight component is easily soluble, a residue (residual portion) is likely to occur in the exposed portion on the substrate of the FPC. As a result of diligent investigation, the surface of the polyimide resin is considered to be easily deteriorated. As a result, the molecular weight distribution of the polyimide resin is set to a specific range, and the molecular weight distribution is made to be a single distribution and narrowed so that both excellent developability and plating resistance can be achieved. And the present invention (photosensitive polyimide composition) was completed.

  The inventor further provides a method for synthesizing a soluble polyimide resin by condensation of an aromatic tetracarboxylic dianhydride and a diamine, wherein the aromatic tetracarboxylic dianhydride and a part of the silicone diamine are insoluble in the reaction solvent. It was found that the soluble polyimide resin constituting the photosensitive polyimide composition of the present invention can be easily synthesized by starting polymerization (condensation) in a suspended state and dissolving them as the polymerization proceeds. The method of the invention (a method for producing a soluble polyimide resin, a method for producing a photosensitive polyimide composition) was completed.

  In the conventional synthesis method, the molecular weight and the molecular weight distribution are easily changed for each synthesis (polymerization) lot, and as a result, the development property and the plating resistance are deteriorated. However, this problem is solved by the method of the present invention. .

The present invention, as claim 1 thereof,
A photosensitive resin composition containing a soluble polyimide resin and a positive photosensitive agent,
The soluble polyimide resin is a condensate of aromatic tetracarboxylic dianhydride and diamine,
The diamine contains a silicone diamine and a diamine having a hydroxyl group,
Provided is a photosensitive polyimide composition, wherein the soluble polyimide resin has a weight average molecular weight of 20,000 to 50,000, a molecular weight distribution of one peak distribution, and a dispersion of 2.0 or less.

  The condensate of aromatic tetracarboxylic dianhydride and diamine means a reaction product obtained by condensing aromatic tetracarboxylic dianhydride and diamine in an equimolar amount of about 1: 1.

  Here, the diamine having a hydroxyl group is preferably hexafluoro-2,2-bis (3-amino-4-hydroxyphenyl) propane (hereinafter referred to as 6FAP) represented by the following structural formula (II) ( Claim 2). By using 6FAP, film deterioration and film loss during development can be reduced.

  The copolymerization ratio of the diamine having a hydroxyl group, that is, the ratio of the diamine having a hydroxyl group in the total diamine used for the condensation is preferably in the range of 1 to 50 mol% (Claim 3). The smaller the copolymerization ratio of the diamine having a hydroxyl group, the lower the developability when forming a protective film (coating pattern) using the resulting photosensitive polyimide composition. As a result, in order to achieve sufficient development, a concentrated alkaline solution or organic solvent is required as a developer. On the other hand, the greater the copolymerization ratio of the diamine having a hydroxyl group, the lower the heat resistance of the coating film formed by applying and curing the composition to a substrate or the like, and the lower the plating resistance of the coating film. Therefore, the range of 1 to 50 mol% is preferable from the viewpoints of developability and plating resistance.

  Silicone diamine is a compound having a siloxane group in the skeleton and two primary amino groups at its ends, for example, those represented by the following structural formula (III) are widely used.

  In the formula, a represents a number of about 1 to 10,000. In addition to the above, those represented by the following structural formulas are also exemplified.

式中、ａ＋ｂ（式がｂを含まない場合はａ）は１〜１００００程度の数を表す。

In the formula, a + b (a when the formula does not include b) represents a number of about 1 to 10,000.

  The soluble polyimide resin that is the base polymer of the photosensitive polyimide composition of the present invention has a weight average molecular weight in the range of 20000 to 50000, a single molecular distribution, and a dispersion of 2.0 or less. By adding a photosensitizer to a soluble polyimide resin having such an average molecular weight, molecular weight distribution, and dispersion, high photosensitivity and developability can be obtained as a photosensitive polyimide composition, and development residues are less likely to occur during development. And the heat resistance, solvent resistance, and plating resistance of the coating film obtained from this composition are excellent, and a protective film satisfying the required characteristics can be easily obtained.

  In particular, when the weight average molecular weight is in the range of 25,000 to 45,000, a protective film having further excellent characteristics can be obtained. Here, the single-peak distribution means that the molecular weight distribution curve has substantially one peak. Further, the dispersion represents the extent of the molecular weight distribution, and is specifically a value of (weight average molecular weight / number average molecular weight). Here, the weight average molecular weight, the number average molecular weight, and the molecular weight distribution curve are values measured by GPC and calculated by using standard polystyrene (TSK standard polystyrene).

  It is preferable that content of silicone diamine is 5-60 mol% with respect to all the diamine (Claim 4). In particular, when the molecular weight of the silicone diamine is about 500 to 1,000, it is preferably 10 to 60 mol% with respect to the total diamine. When it exceeds 60 mol%, the glass transition temperature of the film is lowered and the heat resistance is lowered. On the other hand, when it is less than 5 mol%, the warpage of the film tends to increase. More preferably, it is the range of 30-50 mol%. However, heat resistance and film warpage are also affected by the structure and content of other diamines.

  Specifically, as silicone diamine, BY16-853U, BY16-853C manufactured by Toray Dow Corning Silicone, X-22-1660B-3, KF-8010, X-22-161A manufactured by Shin-Etsu Chemical Co., Ltd. And X-22-161B and LS-7430 (1,3-bis (3-aminopropyl) tetramethyldisiloxane).

  The weight average molecular weight of the silicone diamine is preferably 1000 or less (Claim 5). At this time, a in the formula (III) is about 8 to 9 or less. When the weight average molecular weight exceeds 1000, the adhesive strength with a copper foil or the like tends to decrease.

  The diamine that can be used for the production of the soluble polyimide resin that is the base polymer of the photosensitive polyimide composition of the present invention includes the above-mentioned diamine having a hydroxyl group and the above-mentioned silicone diamine, which is contrary to the spirit of the present invention. Other diamines are included as long as they are not.

  Examples of other diamines include bis (3-aminopropyl) ether ethane, 3,3′-diamino-4,4′dihydroxydiphenylsulfone, 4,4′diamino-3,3′dihydroxybiphenyl, 2,2 -Bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, siloxane diamine, bis (3-aminopropyl) ether ethane, N, N-bis (3-aminopropyl) ether, 1,4-bis (3 -Aminopropyl) piperazine, isophoronediamine, 1,3'-bis (aminomethyl) cyclohexane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis (cyclohexylamine), 4, 4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, , 3′-diaminodiphenyl ether, 4,4′-diamino-diphenyl sulfone, 3,4′-diamino-diphenyl sulfone, 3,3′-diamino-diphenyl sulfone, 2,4′-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4- Aminophenoxy) phenyl] hexafluoropropane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 4,4′bis (4-aminophenoxy) biphenyl, 1,4-bis (4-aminophenoxy) benzene, 4,4'-diaminodiphenyl sulfide 3,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 3,3′diamino-4,4′dihydroxydiphenyl sulfone, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5- Diaminobenzoic acid, 2,6-diaminopyridine, 4,4′diamino-3,3′dimethoxybiphenyl, 4,4′diamino-3,3′dimethylbiphenyl, 9,9′-bis (4-aminophenyl) fluorene Etc.

  Among these, 1,3-bis (3-aminophenoxy) benzene (hereinafter referred to as “1,3-APB”) represented by the following structural formula (IV) is preferable from the viewpoint of transparency and flexibility. used.

  Moreover, the use of bis [4- (3-aminophenoxy) phenyl] sulfone or 1,4-bis (3-aminophenoxy) benzene is also preferred. Furthermore, 1,3-APB and diamines represented by the following structural formulas can also be used.

  The aromatic tetracarboxylic dianhydride constituting the soluble polyimide resin that is the base polymer of the photosensitive polyimide composition of the present invention includes 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3, 3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, bicyclo (2, 2,2) -Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, pyromellitic dianhydride, 2 , 2-bis (3,4-dicarboxylphenyl) hexafluoropropane dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-di Carboxylic acid dianhydride and the like.

  Among these, 4,4′-oxydiphthalic dianhydride (hereinafter referred to as “OPDA”) represented by the following formula (V) is preferable from the viewpoint of transparency and flexibility, and therefore an aromatic containing OPDA. Tetracarboxylic dianhydride is preferably used (claim 6).

  The photosensitive polyimide composition of the present invention is used for forming an FPC protective film, etc., but has developability comparable to that of conventional photosensitive polyimide compositions, and hardly causes problems such as residues. Is. On the other hand, it is also excellent in plating resistance and is less prone to defects such as deterioration and spot discoloration in the gold plating process.

  In many cases, the soluble polyimide resin used in the photosensitive polyimide composition of the present invention is already imidized at the stage of synthesis. Therefore, heating for forming an imide ring is not necessary, and a heat treatment step may be performed as necessary after pattern formation. This is performed to evaporate residual solvent contained in the pattern. Therefore, heating at a high temperature necessary for forming an imide ring is unnecessary.

The soluble polyimide resin that is the base polymer of the photosensitive polyimide composition of the present invention,
A condensation reaction step of condensing an aromatic tetracarboxylic dianhydride with a diamine containing a silicone diamine and a diamine having a hydroxyl group;
The condensation reaction step starts the condensation with the aromatic tetracarboxylic dianhydride and the silicone diamine suspended in a solvent that dissolves only a part of the aromatic tetracarboxylic dianhydride and the silicone diamine. Then, it can be produced by a method characterized by dissolving an aromatic tetracarboxylic dianhydride and silicone diamine in the solvent while raising the temperature. This invention provides the manufacturing method of this soluble polyimide resin in Claim 7.

  The method for producing a soluble polyimide resin of the present invention is the same as the conventional method for producing a polyimide resin in that it has a condensation reaction step of condensing an aromatic tetracarboxylic dianhydride and a diamine. However, in the production method of the present invention, in the condensation reaction of aromatic tetracarboxylic dianhydride and diamine, aromatic tetracarboxylic dianhydride and aromatic tetracarboxylic dianhydride are dissolved in a solvent that dissolves only a part of silicone diamine. The condensation is started in a state where the acid dianhydride and the silicone diamine are suspended, and then the condensation is further performed by dissolving the aromatic tetracarboxylic dianhydride and the silicone diamine in the solvent while raising the temperature. And

  Examples of the solvent that dissolves only a part of the aromatic tetracarboxylic dianhydride and the silicone diamine include γ-butyrolactone. Therefore, in a preferred embodiment of the method for producing the soluble polyimide resin according to the present invention, the aromatic tetracarboxylic dianhydride contains OPDA, the diamine having a hydroxyl group is 6FAP, and A method is provided wherein the solvent is γ-butyrolactone (claim 8).

  In the method of claim 8, first, the silicone diamine is added to the solvent γ-butyrolactone, and then the aromatic tetracarboxylic dianhydride OPDA is gradually added, followed by stirring for a predetermined time to polymerize. Let it begin. Alternatively, the aromatic tetracarboxylic dianhydride may be first added to the solvent γ-butyrolactone, and then the silicone diamine may be gradually added to initiate the polymerization. Since it is room temperature at this time, OPDA of silicone diamine and aromatic tetracarboxylic dianhydride is hard to melt | dissolve, a part melt | dissolves and the remainder suspends. Thereafter, the reaction system is heated and heated. Silicone diamine and OPDA react gradually and dissolve in γ-butyrolactone as the temperature rises. When the temperature is raised to a predetermined temperature, the reaction is performed at that temperature for a predetermined time. Thereafter, the heating is stopped and the mixture is naturally cooled to around room temperature.

  Thereby, the soluble polyimide resin (polyimide silicone) whose weight average molecular weight is the range of 20000-50000, the molecular weight distribution is 1 peak distribution, and dispersion | distribution is 2.0 or less can be obtained easily.

  Instead of γ-butyrolactone alone as a solvent, a mixed solvent in which methyl benzoate, ethyl benzoate, methyl ethyl ketone (MEK), acetone, etc. are mixed in γ-butyrolactone is used to dissolve the entire amount of silicone diamine and OPDA from the beginning of the reaction. When the reaction proceeds in a homogeneous system, it becomes a molecular weight distribution of two peaks with another peak on the high molecular weight side. As a result, developability deteriorates and a residue is likely to remain in the exposed area.

  The photosensitive polyimide composition of the present invention can be obtained by mixing the soluble polyimide resin thus produced and a positive photosensitive agent. The present invention also provides a method for producing the photosensitive polyimide composition (claim 9). This mixing step can be performed in the same manner as in the case of a conventional photosensitive polyimide composition, for example, by dissolving the soluble polyimide resin and the positive photosensitive agent in a solvent.

  Examples of the positive photosensitive agent include naphthoquinonediazide compounds, and more specifically 1,2-naphthoquinone-2-diazide-5-sulfonic acid ester and 1,2-naphthoquinone-2-diazide-4-sulfonic acid. Examples include esters, 2,3,4-trihydroxybenzophenone, and 6, diadia-dihydro-5-oxo-1-naphthalenesulfonic acid ester of 2,3,4,4′-tetrahydroxybenzophenone. Specific product names include PC-5, NT-200, 4NT-300 manufactured by Toyo Gosei Co., Ltd., DTEP-300 manufactured by Daitokemix Co., Ltd., DTEP-350, and the like.

  As the solvent, an aprotic polar solvent is preferable, and N-methyl-2-pyrrolidone, N, N′-dimethylacetamide, dimethylformamide, dimethylsulfoxide, acetonitrile, diglyme, γ-butyrolactone, γ-valerolactone, phenol, toluene , Dioxane, tetrahydrofuran, sulfolane, hexamethylphosphoramide and the like. Among these, γ-butyrolactone is preferably used from the viewpoint of high volatility, odor and the like. The amount used is preferably 1 to 20 times (weight ratio) of the soluble polyimide resin.

  It is preferable to use the same solvent as that used for the synthesis of the soluble polyimide resin as the solvent because a solvent replacement operation is not necessary in the production of the photosensitive polyimide composition. Therefore, when OPDA is used as the aromatic tetracarboxylic dianhydride, γ-butyrolactone is preferable from this viewpoint.

  By using the photosensitive polyimide composition of the present invention, an FPC protective film is formed which is not easily deteriorated in the gold plating process, in particular, less likely to cause spot discoloration, and has sufficient adhesion to copper foil. be able to. Furthermore, also in the formation process of the protective film of this FPC, the developability similar to the conventional photosensitive polyimide composition is exhibited, and the residue and the like are small. That is, it becomes possible to achieve both excellent developability and plating resistance.

  Moreover, the photosensitive polyimide composition which has the said effect can be easily manufactured with the manufacturing method of the soluble polyimide resin of this invention, and the manufacturing method of the photosensitive polyimide composition.

  Next, the best mode for carrying out the present invention will be described below with reference to examples, but the present invention is not limited to these examples.

(Example 1)
(Synthesis of soluble polyimide resin)
1. In a 1 L-separable flask equipped with a cooler, a mechanical stirrer, and a nitrogen introduction tube, in a nitrogen atmosphere, 140 g of γ-butyrolactone as a solvent was added to a silicone diamine (a compound represented by the structural formula (III)). KF8010 manufactured by Shin-Etsu Silicone Co., Ltd., molecular weight: 830, amine equivalent: 415) 49.80 g (0.06 mol) is added to dissolve a part, and the rest is suspended. Further, 2.0 g of pyridine as a catalyst and 100 g of toluene as an azeotropic solvent are added.

2. As an aromatic tetracarboxylic dianhydride, 37.22 g (0.12 mol) of OPDA (molecular weight: 310.2) is gradually added and charged in its entirety. At this time, a part of OPDA is dissolved and the rest is suspended. The mixture is stirred for 15 minutes, and further heated to 160 ° C. with a mantle heater while refluxing toluene, and allowed to react for 1 hour. During this time, the silicone diamine and OPDA are gradually dissolved and condensed. Thereafter, the heating is stopped and the mixture is naturally cooled to around room temperature (50 ° C. or lower).

3. Next, as diamine, 1,3-APB (molecular weight: 292.3) 5.85 g (0.02 mol) and 6FAP (molecular weight: 366) 14.64 g (0.04 mol) were added, and about 40% Add 15 g of solvent γ-butyrolactone so as to have a solid content. The mixture is stirred for 15 minutes and then heated to 160 ° C. in an oil bath and reacted for 3 hours to obtain a reaction solution. Thereafter, the pressure was reduced and toluene and pyridine were removed from the reaction solution to obtain a varnish.

  The varnish thus obtained was subjected to the following measurements. The results are shown in Table 1.

(Molecular weight measurement)
The dispersion (Mw / Mn), which is the ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn), of the obtained varnish was measured by GPC (manufactured by Tosoh Corporation, HLC-8220GPC). As a column, TSKgel GMH _HR- H manufactured by Tosoh Corporation was used, and as a carrier solvent, a solution obtained by dissolving LiBr in NMP at a concentration of 0.1 N was used. The molecular weight is a converted value calculated using standard polystyrene (TSK standard polystyrene). The GPC chart of the obtained varnish is shown in FIG.

(Evaluation of photosensitive developability)
To the obtained varnish, 15 phr of 1,2-naphthoquinone-2-diazide-5-sulfonic acid ester (manufactured by Toyo Gosei Co., Ltd., hereinafter referred to as PC5) was added and mixed as a photosensitive agent, and a photosensitive polyimide composition ( Photosensitive ink) was prepared. The photosensitive ink was applied by screen printing onto a 18 μm thick copper foil and then prebaked to obtain a 12 to 15 μm thick film. This film was exposed to 1000 mJ / cm ^{2 of} mercury lamp light through a predetermined mask.

  Development was performed by showering the developer using a conveyor-type development line. The developer used was 2.3% NaOH + 0.5% ethanolamine aqueous solution (40 ° C.). The 2 m developed part is rinsed pure and then dried at 80 ° C. The state of the dried film was visually observed and evaluated according to the following criteria. The results are shown in Table 1.

A: Clear patterning is possible up to L / S of 50 μm or less, and no deterioration of the film or penetration into the interface is observed.
○: Patterning is possible up to L / S of about 50 μm, and there is no residue. There is no deterioration of the film.
(Triangle | delta): Although it has patterned mostly, a residue is seen in an exposure part or deterioration of a film | membrane is seen.
X: Patterning is not possible or deterioration is remarkable.

(Evaluation of plating resistance)
Each photosensitive ink is applied onto a copper foil having a thickness of 18 μm, dried to form a resist film having a thickness of 12 to 15 μm, and irradiated with light through a predetermined mask. After development with electroless gold plating. The state after plating was observed and evaluated according to the following criteria. The results are shown in Table 1.

A: The number of spots observed is 0.3 or less per sample piece.
(Triangle | delta): The number of spots observed is larger than 0.3 and 1.0 or less per sample piece.
X: The number of spots observed is greater than 1.0 per piece of sample.

(Example 2)
Except that ABPS was used instead of 6FAP, the same reaction as in Example 1 was performed to produce a varnish, and the same measurement was performed.

(Comparative Example 1)
A varnish was produced in the same manner as in Example 1 except that a mixed solvent in which 40 g of methyl benzoate was mixed with 100 g of γ-butyrolactone was used instead of 140 g of γ-butyrolactone as a solvent. In this reaction, silicone diamine and OPDA were completely dissolved from the beginning of the reaction, and there was no portion to be suspended. The varnish of Comparative Example 1 thus obtained was measured in the same manner as the varnish of Example 1. The results are also shown in Table 1. Moreover, the GPC chart of the obtained varnish is shown in FIG.

(Comparative Example 2)
Instead of 140 g of γ-butyrolactone as a solvent, a mixed solvent obtained by mixing 40 g of methyl benzoate with 100 g of γ-butyrolactone was used, and except that ABPS was used instead of 6FAP, the same reaction as in Example 1 was performed, and the varnish was obtained. Manufactured. Also in this reaction, silicone diamine and OPDA were completely dissolved from the beginning of the reaction, and there was no portion to be suspended.

  As shown in Table 1, according to the photosensitive polyimide compositions of Examples 1 and 2 which are products of the present invention, both excellent developability and plating resistance can be achieved, whereas Comparative Example 1 In the photosensitive polyimide composition, it is difficult to achieve both excellent developability and plating resistance. In particular, in Comparative Example 2 in which 6FAP is not used, the plating resistance is inferior.

2 is a GPC chart of varnishes obtained in Example 1 and Comparative Example 1.

Claims (9)

A photosensitive resin composition containing a soluble polyimide resin and a positive photosensitive agent,
The soluble polyimide resin is a condensate of aromatic tetracarboxylic dianhydride and diamine,
The diamine contains a silicone diamine and a diamine having a hydroxyl group,
The soluble polyimide resin has a weight average molecular weight of 20,000 to 50,000, a molecular weight distribution of one peak distribution, and a dispersion of 2.0 or less.   The photosensitive polyimide composition according to claim 1, wherein the diamine having a hydroxyl group is hexafluoro-2,2-bis (3-amino-4-hydroxyphenyl) propane.   Content of the diamine which has the said hydroxyl group is 1-50 mol% with respect to all the diamines, The photosensitive polyimide composition of Claim 1 or Claim 2 characterized by the above-mentioned.   The photosensitive polyimide composition according to any one of claims 1 to 3, wherein the content of the silicone diamine is 5 to 60 mol% with respect to the total diamine.   The photosensitive polyimide composition according to claim 1, wherein the silicone diamine has a weight average molecular weight of 1000 or less.   The photosensitive polyimide composition according to any one of claims 1 to 5, wherein the aromatic tetracarboxylic dianhydride contains 4,4'-oxydiphthalic dianhydride. A condensation reaction step of condensing an aromatic tetracarboxylic dianhydride with a diamine containing a silicone diamine and a diamine having a hydroxyl group;
The condensation reaction step starts the condensation with the aromatic tetracarboxylic dianhydride and the silicone diamine suspended in a solvent that dissolves only a part of the aromatic tetracarboxylic dianhydride and the silicone diamine. Then, a process for producing a soluble polyimide resin, which is carried out by dissolving aromatic tetracarboxylic dianhydride and silicone diamine in the solvent while raising the temperature.   The aromatic tetracarboxylic dianhydride contains 4,4′-oxydiphthalic dianhydride, and the diamine having a hydroxyl group is hexafluoro-2,2-bis (3-amino-4- The method for producing a soluble polyimide resin according to claim 7, wherein the solvent is γ-butyrolactone.   A method for producing a photosensitive polyimide composition, comprising: producing a soluble polyimide resin by the method for producing a soluble polyimide resin according to claim 7 or 8; and then mixing the soluble polyimide resin and a positive photosensitive agent. .

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