JP4969941B2 - Polyimide composition, flexible wiring board and method for producing flexible wiring board - Google Patents

Description

  The present invention relates to a polyimide composition and a flexible wiring board having a polyimide layer formed of the polyimide composition, and relates to a method of manufacturing the flexible wiring board.

  Generally, a polyimide resin is easily obtained by reacting an aromatic tetracarboxylic dianhydride such as pyromellitic dianhydride and an aromatic diamine such as diaminodiphenyl ether in an aprotic polar solvent such as dimethylacetamide. It is obtained by film-forming a polyimide precursor having a high polymerization degree and heating or chemical imidization.

  And since this polyimide resin has properties such as chemical resistance, radiation resistance, electrical insulation, and mechanical properties, it is formed on conductors such as copper foil and is used in various electronic devices such as flexible wiring boards. Widely used.

  As a polyimide composition for forming a polyimide resin used for an electronic device such as a flexible wiring board, there is a composition in which a polymaleimide is contained in a fluorinated terminal amine oligomer (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 03-179026

  Generally, when a polyimide resin is used for an electronic device such as a flexible wiring board, it is necessary to form a polymer on a conductor. Therefore, it is necessary to prepolymerize the film before forming a film on a conductor. The polyimide resin disclosed in Patent Document 1 cannot be formed with only a fluorinated terminal amine oligomer. Therefore, polymaleimide is contained and heated to improve the film forming property by prepolymerizing the terminal amine oligomer. ing. Moreover, this polymaleimide becomes a crosslinking agent and improves heat resistance.

  The polyimide composition forming such a polyimide resin is subjected to pattern formation by alkali development so as to have a predetermined shape on the conductor. For example, a pattern can be formed by removing a predetermined portion with an alkaline solution such as sodium hydroxide or potassium hydroxide.

  However, if the polymaleimide that improves the heat resistance as described above is contained in the composition, the additive polymaleimide absorbs light, so that the photosensitive agent cannot be efficiently exposed. . Therefore, in a composition like patent document 1, when heat resistance is improved, alkali developability will fall under the influence of a crosslinking agent, and when alkali developability is improved, heat resistance will fall.

  Therefore, the present invention aims to provide a polyimide composition that has heat resistance and does not affect alkali developability, that is, has both heat resistance and alkali developability, and uses the polyimide composition. A flexible wiring board and a manufacturing method thereof are provided.

  The polyimide composition of the present invention includes an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and a second having an alkylene structure in the molecule. It is synthesized by polymerization with a diamine monomer having a diamine, and contains an imide oligomer having an amino group at a terminal, a crosslinking agent having a plurality of maleimide groups, and a photosensitizer.

  The polyimide composition of the present invention has photosensitizer, imparts photosensitivity, and enables alkali development. And an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and a diamine monomer having a second diamine having an alkylene structure in the molecule; By using, the alkali solubility of the synthesized imide oligomer is improved. Therefore, even when a crosslinking agent having a plurality of maleimide groups is added, the alkali developability is not affected and heat resistance can be imparted.

  The flexible wiring board of the present invention includes a conductor, an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride on the conductor, a first diamine having a hydroxyl group, and a molecule. Polyimide composition synthesized by polymerization with a diamine monomer having a second diamine having an alkylene structure therein, and containing an imide oligomer having an amino group at a terminal, a crosslinking agent having a plurality of maleimide groups, and a photosensitizer And a polyimide layer.

  The flexible wiring board of the present invention has a polyimide layer made of a polyimide composition imparted with photosensitivity by a photosensitizer and improved in heat resistance by a crosslinking agent. The polyimide layer includes an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and a second diamine having an alkylene structure in the molecule. It is easy to dissolve in an alkaline solution by using a diamine monomer having. Therefore, the flexible wiring board of the present invention can form a predetermined pattern by exposure and alkali development with an alkaline solution even when a crosslinking agent for improving heat resistance is added.

  The method for producing a flexible wiring board of the present invention includes an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and an alkylene structure in the molecule. And a step of synthesizing an imide oligomer having an amino group at a terminal by polymerization with a diamine monomer having a second diamine, and a step of forming a polyimide composition by adding a photosensitizer and a crosslinking agent to the imide oligomer. The polyimide composition is applied to a conductor to form a polyimide layer, and the conductor having the polyimide layer is exposed to light and then immersed in the alkaline solution to form a predetermined pattern. To do.

  According to the method for producing a flexible wiring board of the present invention, a polyimide layer made of a polyimide composition that is imparted with photosensitivity by a photosensitizer and improved in heat resistance by a crosslinking agent is formed. The polyimide layer includes an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and a second diamine having an alkylene structure in the molecule. The imide oligomer to be synthesized can be easily dissolved in an alkali solution by using a diamine monomer having a diamine monomer, and a predetermined pattern can be formed by exposure and alkali development with an alkali solution even when a crosslinking agent is added. it can. Therefore, a flexible wiring board having alkali developability and heat resistance can be produced.

  By having a photosensitizer, the present invention imparts photosensitivity and enables alkali development. And an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and a diamine monomer having a second diamine having an alkylene structure in the molecule; By using, the alkali solubility of the imide oligomer formed is improved. Therefore, even when a crosslinking agent having a plurality of maleimide groups is added, the alkali developability is not affected and heat resistance can be imparted. Therefore, by using this polyimide composition, a flexible wiring board having alkali developability and heat resistance is obtained.

  Hereinafter, the polyimide composition of this invention and the manufacturing method of a polyimide composition are demonstrated. Note that the present invention is not limited to the following description, and can be appropriately changed without departing from the spirit of the present invention.

  The polyimide composition of the present invention is a polyimide composition having both heat resistance and alkali developability. This polyimide composition contains an imide oligomer, a photosensitive agent, and a crosslinking agent having a plurality of maleimide groups.

  The imide oligomer constituting the polyimide composition of the present invention can be synthesized by polymerizing an acid dianhydride monomer and a diamine monomer. In the synthesis of the imide oligomer, 3,3′-diphenylsulfonetetracarboxylic dianhydride (DSDA) is used as the acid dianhydride monomer.

  This DSDA can improve the alkali solubility of the imide oligomer synthesized. This DSDA has sulfur and oxygen atoms with high electronegativity, and these atoms reach the imide carbonyl carbon through conjugation and are susceptible to base nucleophilic attack, so that alkali solubility is improved. It is thought to be a thing.

  The DSDA is not particularly limited as long as it is used in an amount less than the amount of the diamine monomer so that an imide oligomer having an amino group at the terminal can be synthesized by reaction with the following diamine monomer.

  As the diamine monomer that is polymerized with DSDA to synthesize an imide oligomer, an arbitrary diamine monomer having a hydroxyl group in the molecule is used. For example, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (BIS-AP-AF) is an example of a diamine.

  Since this BIS-AP-AF has a hydroxyl group, alkali solubility becomes high and alkali development becomes easy. This BIS-AP-AF is a highly flexible diamine and has a trifluoromethyl group in the molecule. A trifluoromethyl group is a bulky substituent that weakens the interaction between molecular chains. Therefore, the high flexibility and the trifluoromethyl group improve the solubility in a solvent. Thereby, when using the polyimide composition of this invention for a flexible wiring board, handling becomes easy and it can form the film | membrane of a uniform polyimide on a conductor.

  The amount of BIS-AP-AF in the diamine monomer is preferably at least 1 mol% in the diamine monomer. When the amount of BIS-AP-AF is 1 mol% or less, sufficient solvent and alkali solubility cannot be imparted.

  In addition to BIS-AP-AF, this first diamine is 4,4′-diamino-3,3′-biphenyldiol (HAB), 9,9-bis (3-amino-4-hydroxyphenyl) fluorene. (BAHF), 3,3′-diamino-4,4′-dihydroxydiphenylsulfone (BS-DA) and the like can also be applied.

  And as for the diamine monomer made to react with an acid dianhydride monomer with BIS-AP-AF which is 1st diamine, the 2nd diamine which has a C4 or more alkylene structure in a molecule | numerator as 2nd diamine is mentioned. . By having an alkylene structure, the flexibility of diamine increases and a film having a low elastic modulus is formed.

  As this 2nd diamine, it is preferable to use the diamine shown by the following general formula (1) or the following general formula (2).

  As a 2nd diamine shown by General formula (1), it is preferable that n in the said General formula (1) is an integer greater than or equal to 4. In General Formula (1), when the methylene unit is 4 or more, that is, n is 4 or more, the flexibility of the diamine is increased, and a polyimide having a low elastic modulus can be formed. Since a polyimide having a low elastic modulus can be formed, for example, when a polyimide layer is formed on a conductor with a flexible wiring board or the like, it is possible to improve the warpage caused by the difference in the coefficient of thermal expansion between the conductor and polyimide. That is, a flexible wiring board with less warping can be provided.

  And in general formula (1), it is still more preferable that a methylene unit is 40 or more, ie, n is 40 or more. Thereby, since the molecular weight of the monomer has reached nearly 1000, even if the degree of polymerization is as low as that of an oligomer (calculated degree of polymerization is about 20), the average molecular weight exceeds 10,000 and film formation becomes possible. Further, the alkali solubility of the synthesized imide oligomer in the alkali solution is very good.

  Moreover, as a 2nd diamine shown by General formula (2), it is preferable that m in the said General formula (2) is an integer greater than or equal to 10. In the general formula (2), when the tetramethylene oxide unit is 10 or more, that is, m is 10 or more, the same effect as when n in the general formula (1) is 40 or more can be obtained, Is preferred. An example of such a diamine is Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000.

  The second diamine is preferably contained in an amount of 30 wt% or more based on the weight of the total monomer including the acid dianhydride monomer and the diamine monomer. By using 30 wt% or more of the second diamine, film formation on a conductor or the like is improved.

  The second diamine is more preferably contained in an amount of 45 wt% or more based on the weight of all monomers including the acid dianhydride monomer and the diamine monomer. By using 45 wt% or more of the second diamine, a polyimide having improved solubility in an alkaline solution and a low elastic modulus can be formed. Therefore, it becomes a flexible wiring board with no warp and good alkali developability.

  The imide oligomer is synthesized by polymerizing DSDA as an acid dianhydride monomer and the above-mentioned first diamine and second diamine as a diamine monomer. After reacting an acid dianhydride monomer and a diamine monomer to produce an amic acid (imide precursor) component, heating and advancing imidization in the solution cause the amic acid component to ring-close, It can be synthesized (solution imidization). The solution imidization means may be any conditions as long as the cyclization dehydration reaction can be performed, and examples thereof include heating imidization in a solution and chemical imidization with a dehydrating agent. For example, in heat imidization, an azeotropic agent such as toluene and xylene is added to an imide precursor, and the mixture is heated and stirred at 180 ° C. or higher to perform a dehydration reaction of an amic acid component to form a ring-closed imide component. be able to. At this time, a tertiary catalyst such as triethylamine, a basic catalyst such as aromatic isoquinoline and pyridine, and an acid catalyst such as benzoic acid and parahydroxybenzoic acid may be added as a catalyst for imidization, if necessary. Further, for example, the amic acid can also be closed by a chemical imidizing agent such as acetic anhydride / pyridine or dicyclohexylcarbodiimide which is a dehydrating cyclization reagent. As for the usage-amount of a diamine monomer and an acid dianhydride monomer, it is preferable to make the diamine monomer excess. Thereby, the imide oligomer which has an amino group at the terminal is synthesized. By making the terminal an amino group, this amino group reacts with the maleimide group of the following crosslinking agent, and the heat resistance of the polyimide can be improved.

  The imide oligomer synthesized by polymerization of the acid dianhydride monomer and the diamine monomer is not particularly limited as long as it is an oligomer, but the amount of the acid dianhydride monomer and the amount of the diamine monomer are adjusted. The calculated degree of polymerization of the imide oligomer is, for example, about 20. For example, when the acid dianhydride monomer is 90 mol% and the diamine monomer is 100 mol%, the calculated polymerization degree becomes 19. With this calculated degree of polymerization, the number average molecular weight exceeds 10,000 when the second diamine having a relatively large molecular weight is used as the monomer. Thereby, even an oligomer can be formed on a conductor or the like. On the contrary, there is a necessary minimum number average molecular weight capable of forming a film even with an oligomer. You may grasp | ascertain this minimum required number average molecular weight, and may adjust the quantity of the acid dianhydride monomer and the quantity of a diamine monomer which become the calculation polymerization degree which satisfy | fills this number average molecular weight.

  This imide oligomer dissolves the acid dianhydride monomer and the diamine monomer as described above in a solvent such as N-methyl-2-pyrrolidone (NMP) and performs addition polymerization of the acid dianhydride and the diamine in the solvent. To synthesize. Here, as a solvent to be used, for example, an aprotic amide solvent such as NMP and N, N-dimethylacetamide, and a phenolic solvent such as cresol can be used. preferable. Also, xylene, toluene, ethylene glycol monoethyl ether, etc. can be mixed and used.

  The polyimide composition contains a photosensitizer. By containing this photosensitizer, photosensitivity can be imparted to the formed polyimide composition. Examples of the photosensitizer include a diazonaphthoquinone compound. The polyimide composition containing the diazonaphthoquinone compound changes in alkali solubility upon exposure. Before exposure, the solubility in an alkaline solution is low. On the other hand, after exposure, the molecular structure of the diazonaphthoquinone compound changes to produce ketene, which reacts with an alkaline solution to produce carboxylic acid. The produced carboxylic acid is further reacted with water and dissolved. Therefore, the solubility to an alkaline solution becomes high by irradiating light.

  By containing the diazonaphthoquinone compound that is a photosensitizer, the hydroxyl group and the diazonaphthoquinone compound hydrogen bond in the imide oligomer having a hydroxyl group and relatively high alkali solubility. Thereby, the hydroxyl group which is easily dissolved in alkali is protected, and the alkali solubility is lowered. When the polyimide compound in this state is exposed to light, the molecular structure of the diazonaphthoquinone compound changes and alkali solubility is exhibited. Therefore, by containing a diazonaphthoquinone compound as a photosensitizer, sodium hydroxide (NaOH), potassium hydroxide, sodium carbonate, sodium bicarbonate, tetramethylammonium hydroxide (TMAH), etc. after exposure to the flexible wiring board. The pattern can be formed with an alkaline aqueous solution.

  The diazonaphthoquinone compound of the photosensitizer is not particularly limited as long as it is a compound having a diazonaphthoquinone skeleton. For example, 2,3,4-trihydroxybenzophenone o-naphthoquinonediazide-4-sulfonic acid ester, 2 3,4-trihydroxybenzophenone o-naphthoquinonediazide-5-sulfonic acid ester, 2,3,4-trihydroxybenzophenone o-benzoquinonediazide-4-sulfonic acid ester, and the like.

  The polyimide composition contains a crosslinking agent having a plurality of maleimide groups. The cross-linking agent having a plurality of maleimide groups causes an addition polymerization of double bonds in the maleimide group and a Michael addition reaction to the terminal amino group of an imide oligomer synthesized with excess diamine monomer. Thereby, the crosslinking agent can bridge | crosslink an imide oligomer. Since this crosslinking agent having a maleimide group causes an addition reaction at a relatively low temperature of about 200 ° C., even if it is used for a flexible wiring board, the influence of heating on other members can be reduced.

  As a quantity which makes this polyimide composition contain this crosslinking agent, it is preferable that it is 50 weight part or less with respect to 100 weight part of imide oligomers. Although this crosslinking agent can improve heat resistance, when it contains more than 50 weight part, since photosensitivity will fall, alkali development becomes difficult.

  The content of the crosslinking agent is more preferably in the range of 10 parts by weight to 30 parts by weight. If the polyimide composition contains an amount of crosslinking agent less than 10 parts by weight, sufficient heat resistance cannot be obtained. Moreover, when a crosslinking agent in an amount larger than 30 parts by weight is contained in the polyimide composition, the elastic modulus increases and causes warping when used in a flexible wiring board.

  The cross-linking agent having a maleimide group is not particularly limited as long as it has good compatibility with the polyimide composition to be formed, and examples thereof include the following compounds. Examples of the crosslinking agent include 4,4′-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4 ′. -Diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, etc. are mentioned.

  The polyimide composition of the present invention is obtained by adding a photosensitizer and a crosslinking agent to a solution in which an imide oligomer synthesized from the above acid dianhydride monomer and a diamine monomer is dissolved in NMP or the like. And a polyimide composition containing a crosslinking agent can be formed.

  This polyimide composition is coated on a conductor, etc., and formed into a film by drying or the like, and then exposed to light to change the structure of the photosensitive agent in the polyimide composition, and the alkali solubility of the exposed portion To increase. Then, by immersing in an alkaline solution, the exposed portion can be removed and a predetermined pattern (positive pattern) can be formed. After the positive pattern is formed, the remaining polyimide composition is heated at about 200 ° C. or higher, so that the crosslinking agent having a maleimide group can crosslink the imide oligomer and form a heat-resistant polyimide. That is, the polyimide composition of the present invention forms a flexible and low-elasticity polyimide, and has alkali developability and heat resistance.

  This polyimide composition can be used for a flexible wiring board as shown in FIG. In this case, a polyimide composition is applied to a conductor such as the copper foil 1 by a known coating method. Then, the polyimide composition is dried to form the polyimide layer 3 on the copper foil 2. The flexible wiring board 1 is exposed with a polyimide layer 3 provided with a mask layer, and then immersed in an alkaline solution and subjected to alkali development to form a predetermined positive pattern on the polyimide layer 3 on the copper foil 2. can do.

  The copper foil 2 having the polyimide layer 3 on which the positive pattern is formed is heated at, for example, about 200 ° C., and the imide oligomer is crosslinked with a crosslinking agent to produce the flexible wiring board 1 having the heat-resistant polyimide layer 3. .

  In the flexible wiring board manufactured by such a method, a polyimide layer made of the above polyimide composition is formed on a conductor such as a copper foil. This polyimide layer is given photosensitivity by a photosensitizer and has high heat resistance by a crosslinking agent. And this polyimide layer uses the 2nd diamine described in the said General formula (1) or General formula (2) for the acid dianhydride monomer which has a 3,3'- diphenyl sulfone tetracarboxylic dianhydride. Thus, even if a crosslinking agent is easily added to the alkali solution, a predetermined pattern can be formed by alkali development. Therefore, a flexible wiring board having alkali developability and heat resistance can be produced.

  Specific examples of the polyimide composition to which the present invention is applied will be described based on experimental results. In this example, test pieces were prepared with the compositions shown in Tables 1 to 4 in Examples 1 to 5 and Comparative Examples 1 to 17, and evaluated according to the following items. The film formability in the table is an evaluation of the film formability on the copper foil. ○ indicates that the film could be formed, △ indicates that the film could be formed, but the film did not form a good film , X indicates a case where the film could not be formed. The warpage in the table is an evaluation related to the warpage of the test piece. The circle indicates that the test piece did not warp, the cross indicates that the test piece has warped, and − indicates that the test is not performed. Further, the developability is an evaluation regarding the alkali developability of the test piece, where ◯ indicates that a predetermined pattern is formed, × indicates that the predetermined pattern cannot be formed, and − indicates that the test is not performed. Furthermore, the heat resistance in the table is an evaluation of the appearance of the polyimide layer under a pressure cooker test (PCT) 121 ° C. × 2 atm × 24 hours × saturated water vapor condition as a heat resistance test. If there is no appearance abnormality and heat resistance, △ indicates that the polyimide layer has some appearance abnormality but heat resistance, × indicates that the polyimide layer has appearance abnormality and there is no heat resistance. Show.

  In Example 1, 7.63 g of BIS-AP-AF (purity 99.00%) and 60.0 g of elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 were weighed into a 500 ml four-necked separable flask. In a nitrogen atmosphere, it was completely dissolved with 210 g of dehydrated NMP. Thereafter, 22.32 g of DSDA (100% purity) was weighed and gradually added. Then, it stirred at 80 degreeC for 2 hours, the Dean-Stark trap (Dean-Stark-Trap) was set, 50 cc of toluene was added, and the reaction liquid was heated up to 180 degreeC. Toluene was refluxed at 180 ° C., and condensed water generated during imidization was removed out of the system. After 4 hours, toluene was recovered from the trap, and further stirred for 1 hour. Thereafter, the reaction vessel was reduced in pressure to completely remove residual toluene, thereby synthesizing an imide oligomer. The calculated degree of polymerization of the imide oligomer at this time is 19.

  To 100 parts by weight of the synthesized imide oligomer, 20 parts by weight of diazonaphthoquinone (NT-200) as a photosensitizer and 20 parts by weight of bisphenol A diphenyl ether bismaleimide (BMI4000: manufactured by Daiwa Kasei Kogyo) as a crosslinking agent are added. A polyimide composition was obtained.

  And this polyimide composition was apply | coated on copper foil so that the polyimide layer after drying might be set to 12 micrometers. This confirmed that the polyimide layer which consists of a polyimide composition was able to be formed into a film on copper foil. It dried for 10 minutes at 100 degreeC, and formed the flexible wiring board as a test piece which has a polyimide layer on copper foil. At this time, the curvature of the test piece after polyimide layer formation was not able to be confirmed.

The polyimide layer of the test piece was irradiated (exposed) with a high-pressure mercury lamp at 50 mW / cm ² and 700 mJ / cm ² through a positive image mask. Then, the polyimide layer on copper foil was immersed in 1 wt% sodium hydroxide aqueous solution, and it was confirmed whether a positive pattern could be formed in a polyimide layer within 90 second. As a result, a positive pattern was formed within 90 seconds.

  After forming the positive pattern, the test piece having the polyimide layer was heated at 200 ° C. for 1 hour in a nitrogen atmosphere to crosslink the imide oligomer. After crosslinking, the test piece was tested for heat resistance using a PCT machine. The test piece was put into a PCT machine (test machine), and taken out from the test machine after 24 hours. Although it was not a favorable result, the appearance abnormality of the polyimide layer of the test piece before and after PCT was not so much, and it confirmed that it had heat resistance.

  In Example 2, an imide oligomer having the same composition as in Example 1 was synthesized. And the quantity of the crosslinking agent was increased to 20 weight part, and the polyimide composition was formed by the method similar to Example 1. FIG. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed.

  The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern was formed within 90 seconds by this alkali development. After the positive pattern was formed, a heat resistance test was performed on the test piece having the polyimide layer. As a result, the appearance abnormality of the polyimide layer of the test piece before and after the PCT was not observed, and it was confirmed that the test piece had heat resistance.

  In Example 3, an imide oligomer having the same composition as in Example 1 was synthesized. And the quantity of the crosslinking agent was increased to 30 weight part, and the polyimide composition was formed by the method similar to Example 1. FIG. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed.

  The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern was formed within 90 seconds by this alkali development. After the positive pattern was formed, a heat resistance test was performed on the test piece having the polyimide layer. As a result, the appearance abnormality of the polyimide layer of the test piece before and after the PCT was not observed, and it was confirmed that the test piece had heat resistance.

  In Example 4, an imide oligomer having the same composition as in Example 1 was synthesized. And the quantity of the crosslinking agent was increased to 40 weight part, and the polyimide composition was formed by the method similar to Example 1. FIG. It was confirmed that a polyimide layer can be formed by applying this polyimide composition on a copper foil. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  Although the warpage of the test piece was confirmed, the same alkali development as in Example 1 was performed on the formed test piece. As a result, a positive pattern was formed within 90 seconds by this alkali development. After the positive pattern was formed, a heat resistance test was performed on the test piece having the polyimide layer. As a result, the appearance abnormality of the polyimide layer of the test piece before and after the PCT was not observed, and it was confirmed that the test piece had heat resistance.

  In Example 5, an imide oligomer having the same composition as in Example 1 was synthesized. And the quantity of the crosslinking agent was increased to 50 weight part, and the polyimide composition was formed by the method similar to Example 1. FIG. It was confirmed that a polyimide layer can be formed by applying this polyimide composition on a copper foil. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  Although the warpage of the test piece was confirmed, the same alkali development as in Example 1 was performed on the formed test piece. As a result, a positive pattern was formed within 90 seconds by this alkali development. After the positive pattern was formed, a heat resistance test was performed on the test piece having the polyimide layer. As a result, the appearance abnormality of the polyimide layer of the test piece before and after the PCT was not observed, and it was confirmed that the test piece had heat resistance.

  In Comparative Example 1, 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride (BPDA) was used as the acid dianhydride monomer, and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industries) as the diamine monomer. Co., Ltd.) 1000 was used at a composition ratio in Table 1 to synthesize a polyimide compound. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed. The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern could not be formed by this alkali development.

  Comparative Example 2 was carried out using BPDA as the acid dianhydride monomer and BIS-AP-AF and trimethylenebis (4-aminobenzoate) (CUA-4) as the diamine monomer in the composition ratios shown in Table 1. A polyimide compound was synthesized in the same manner as in Example 1. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent and a photosensitizer. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  In Comparative Example 3, Example 1 was performed using BPDA as the acid dianhydride monomer and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 as the diamine monomer in the composition ratio of Table 1. Similarly, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Comparative Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed. The alkali development similar to the comparative example 1 was performed with respect to the formed test piece. As a result, a positive pattern could not be formed by this alkali development.

  In Comparative Example 4, BPDA and DSDA were used as acid dianhydride monomers, and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 were used as diamine monomers in the composition ratios shown in Table 1. In the same manner as in Example 1, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed. The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern could not be formed by this alkali development.

  In Comparative Example 5, an imide oligomer was synthesized in the same manner as in Example 1 using DSDA as the acid dianhydride monomer and BIS-AP-AF as the diamine monomer in the composition ratio of Table 1. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied onto a copper foil, and it was confirmed that a polyimide layer could not be formed.

  In Comparative Example 6, an imide oligomer was synthesized in the same manner as in Example 1 using DSDA as the acid dianhydride monomer and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 as the diamine monomer in the composition ratio of Table 1. did. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed. The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern could not be formed by this alkali development.

  In Comparative Example 7, Example 1 was performed using DSDA as the acid dianhydride monomer and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 as the diamine monomer in the composition ratio of Table 2. In the same manner as above, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent and a photosensitizer. This polyimide composition was applied onto a copper foil, and it was confirmed that a polyimide layer could not be formed.

  Comparative Example 8 uses DSDA as the acid dianhydride monomer and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 as the diamine monomer in the composition ratio of Table 2. In the same manner as above, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent and a photosensitizer. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed although it was not a good polyimide layer. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  In comparative example 9, DSDA was used as the acid dianhydride monomer, and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 were used as the diamine monomer in the composition ratios shown in Table 2. In the same manner as above, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  In Comparative Example 10, DSDA was used as the acid dianhydride monomer, and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 were used as the diamine monomer in the composition ratios shown in Table 2. In the same manner as above, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  In Comparative Example 11, DSDA was used as the acid dianhydride monomer, and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 were used as the diamine monomer in the composition ratios shown in Table 2. In the same manner as above, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed.

  The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern was formed within 90 seconds by this alkali development. After the positive pattern was formed, a heat resistance test was performed on the test piece having the polyimide layer. As a result, the appearance abnormality of the polyimide layer of the test piece before and after the PCT was confirmed, and it was confirmed that there was no heat resistance.

  In Comparative Example 12, Example 1 was performed using DSDA as the acid dianhydride monomer and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 as the diamine monomer in the composition ratio of Table 2. In the same manner as above, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed.

  The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern was formed within 90 seconds by this alkali development. After the positive pattern was formed, a heat resistance test was performed on the test piece having the polyimide layer. As a result, the appearance abnormality of the polyimide layer of the test piece before and after the PCT was confirmed, and it was confirmed that there was no heat resistance.

  In Comparative Example 13, Example 1 was performed using DSDA as the acid dianhydride monomer and BIS-AP-AF and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 as the diamine monomer in the composition ratio of Table 3. In the same manner as above, an imide oligomer was synthesized. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed.

  The alkali development similar to Example 1 was performed with respect to the formed test piece. As a result, a positive pattern was formed within 90 seconds by this alkali development. After the positive pattern was formed, a heat resistance test was performed on the test piece having the polyimide layer. As a result, the appearance abnormality of the polyimide layer of the test piece before and after the PCT was confirmed, and it was confirmed that there was no heat resistance.

  In Comparative Example 14, DSDA as the acid dianhydride monomer, BIS-AP-AF as the diamine monomer, Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 and 1,3-bis (3-aminophenoxy) benzene (APB) ) Were used in the composition ratios shown in Table 4 to synthesize imide oligomers as in Example 1. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  In Comparative Example 15, DSDA as the acid dianhydride monomer, BIS-AP-AF as the diamine monomer, Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 and bis [4- (3-aminophenoxy) phenyl] sulfone ( An imide oligomer was synthesized in the same manner as in Example 1 using BAPS-M) at the composition ratio shown in Table 4. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, warpage of the test piece was confirmed.

  In Comparative Example 16, BPDA and pyromellitic dianhydride (PMDA) were used as the acid dianhydride monomer, and BIS-AP-AF and 2,2′-bis (trifluoromethyl) -4,4′- were used as the diamine monomer. A polyimide compound was synthesized in the same manner as in Example 1 using diaminobiphenyl (TFMB) at the composition ratio shown in Table 4. And the polyimide composition was formed by the method similar to Example 1 without using a crosslinking agent. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed. When alkali development was performed on the formed test piece using a 3 wt% aqueous sodium hydroxide solution (3% NaOH aq.), A positive pattern was formed in 150 seconds.

  In Comparative Example 17, a polyimide compound was synthesized in the same manner as in Example 1 using BPDA and PMDA as acid dianhydride monomers and BIS-AP-AF and TFMB as diamine monomers in the composition ratios shown in Table 4. And the polyimide composition was formed by the method similar to Example 1 using 10 weight part of crosslinking agents. This polyimide composition was applied on a copper foil, and it was confirmed that a polyimide layer could be formed. After film formation, it was dried in the same manner as in Example 1 to obtain a test piece. At this time, the warp of the test piece could not be confirmed. When the developed test piece was alkali-developed using a 3 wt% aqueous sodium hydroxide solution (3% NaOH aq.), A positive pattern could be formed in 200 seconds.

  First, as in Comparative Example 16 and Comparative Example 17, the time required for alkali development is increased by adding a crosslinking agent to the polyimide composition. From this, it can be seen that when a crosslinking agent is added to improve heat resistance, alkali developability generally decreases. In the present invention, as in Examples 1 to 5, it is understood that an alkali solution having a concentration lower than that of the alkali solutions used in Comparative Examples 16 and 17 is used, and alkali development can be performed in a shorter time. PCT was found to have heat resistance. That is, it was found that the polyimide composition of the present invention has both heat resistance and alkali developability.

  When Comparative Examples 13 to 15 are compared, when APB or BAPS-M, which is a diamine having a phenylene unit, and Elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 are used in combination as the diamine monomer, the warpage of the test piece is confirmed. I found out that Thereby, in order to improve the curvature of a test piece, it turns out that the diamine which has an alkylene structure is suitable. Further, even in the case of CUA-4 having three methylene units as in Comparative Example 2, since the warpage of the test piece was confirmed, a diamine having four or more relatively long chain methylene units should be suitable. I understood.

  As in Comparative Example 8 and Comparative Example 9, 30 elastomers (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000 as the second diamine are used with respect to the total monomer weight of the acid dianhydride monomer and the diamine monomer. It has been found that when an amount less than% by weight is used, the film formability on the copper foil is lowered. Therefore, good film formability can be obtained by using the second diamine in an amount of 30% by weight or more.

  As in Comparative Example 10 and Comparative Example 11, 45% of elastomer (registered trademark: Ihara Chemical Industry Co., Ltd.) 1000, which is the second diamine, was added to the total monomer weight of the acid dianhydride monomer and the diamine monomer. If an amount less than% by weight is used, warping of the formed specimen is confirmed. Therefore, a flexible wiring board without warping can be provided by using 45% by weight or more of the second diamine.

  Like Example 1 thru | or Example 5, favorable heat resistance and alkali developability are obtained by containing the crosslinking agent of the quantity of 50 weight part or less with respect to 100 weight part of imide oligomers. Moreover, the curvature of the test piece was not confirmed by making the polyimide composition contain the amount of the crosslinking agent in the range of 10 parts by weight or more and 30 parts by weight or less. That is, a flexible wiring board without warping can be provided, which is more preferable.

It is sectional drawing of the flexible wiring board of this invention.

Explanation of symbols

1 Flexible wiring board 2 Conductor 3 Polyimide layer

Claims (9)

An acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and a second diamine having an alkylene structure having 4 or more carbon atoms in the molecule An imide oligomer synthesized by polymerization with a diamine monomer having an amino group at the terminal;
A cross-linking agent having a plurality of maleimide groups;
A polyimide composition comprising a photosensitizer.   The polyimide composition according to claim 1, wherein the first diamine is 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane. The second diamine is represented by the following general formula (1)
The polyimide composition according to claim 1, wherein the polyimide composition is a diamine represented by the formula (1), wherein n is an integer of 4 or more. The second diamine is represented by the following general formula (2)
2. The polyimide composition according to claim 1, wherein the polyimide composition is a diamine represented by the formula (2), wherein m is an integer of 10 or more.   2. The polyimide composition according to claim 1, wherein the second diamine is contained in an amount of 30 wt% or more based on the total monomer weight of the acid dianhydride monomer and the diamine monomer.   2. The polyimide composition according to claim 1, wherein the second diamine is contained in an amount of 45 wt% or more based on the total monomer weight of the acid dianhydride monomer and the diamine monomer.   2. The polyimide composition according to claim 1, wherein the crosslinking agent is contained in an amount of 50 parts by weight or less based on 100 parts by weight of the imide oligomer.   2. The polyimide composition according to claim 1, wherein the crosslinking agent is contained in a range of 10 parts by weight to 30 parts by weight with respect to 100 parts by weight of the imide oligomer. Conductors,
On the conductor, an acid dianhydride monomer having 3,3′-diphenylsulfonetetracarboxylic dianhydride, a first diamine having a hydroxyl group, and a second diamine having an alkylene structure in the molecule It is synthesized by polymerization with a diamine monomer having an imide oligomer having an amino group at a terminal, a cross-linking agent having a plurality of maleimide groups, and a polyimide layer made of a polyimide composition containing a photosensitizer. Flexible wiring board.