JP2009068008A - Polyimide composition, flexible wiring board and manufacturing method of the flexible wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyimide composition which, even after alkali development, does not cause surface deposition of a white powder even when acid cleaning is not conducted, a flexible wiring board obtained using the composition and a manufacturing method thereof, and to provide a polyimide composition which has an improved alkali developability, enables alkali development with sodium carbonate in particular and is suitably used as a cover lay material for a flexible wiring board, a flexible wiring board obtained using the composition and a manufacturing method thereof. <P>SOLUTION: A hydrolyzate produced upon alkali development after light exposure can be fixed into a polyimide by reacting the hydrolyzate with a crosslinking agent. Thus, the surface deposition of the white powder can be prevented without conducting acid cleaning after the alkali development. Selection of a specific material as a component of the polyimide compound can enhance alkali solubility and impart a low elasticity and a flame retardance, which are required of a cover lay material for a flexible wiring board. <P>COPYRIGHT: (C)2009,JPO&INPIT

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. The polyimide precursor having a high degree of polymerization obtained is formed into a film or the like, and is obtained by heating or chemical imidization.

  And since this polyimide resin has properties such as excellent heat resistance, chemical resistance, radiation resistance, electrical insulation and mechanical properties, it is formed on a conductor such as copper foil, Widely used in various electronic devices.

  As a polyimide composition for forming a polyimide resin used for an electronic device such as a flexible wiring board, there is a polyimide composition obtained by uniformly dissolving an acid dianhydride, diaminopolysiloxane, and an epoxy resin in an organic solvent (for example, , See Patent Document 1). In addition, a polyimide composition containing polycarboxylic acid, diisocyanate, polyisocyanate, and epoxy resin is also disclosed, and there is one that provides a highly flexible material (see, for example, Patent Documents 2 and 3).

Japanese Patent No. 2598215 JP 2005-2192 A JP 2004-137370 A

  A photosensitive polyimide composition used for a flexible wiring board or the like is subjected to pattern formation by alkali development so as to have a predetermined shape on a conductor. For example, a pattern can be formed by removing a predetermined portion with an alkaline solution such as sodium hydroxide or potassium hydroxide. The inventors of the present invention conducted a voltage application test (ion migration test) in a moist heat environment after the alkali development, and found that white powder appeared on the surface. The white powder has a weakened layer with reduced molecular weight formed by hydrolyzing the polyimide with the alkaline solution remaining on the polyimide surface that has not been removed by alkali development. It is considered that the hydrolysis progressed and finally became powdery and appeared on the surface. Such exposure of white powder may significantly impair the reliability of electronic components and is an unprecedented problem.

  The above-described polyimide composition of Patent Document 1 contains an epoxy resin in order to compensate for a decrease in heat resistance due to the inclusion of a siloxane component. In Patent Document 1, alkali development with an alkali solution is not performed. The epoxy resin is added to compensate for a decrease in heat resistance and is thermally cured at a temperature equal to or higher than the curing temperature of the epoxy. Therefore, the hydrolyzate from the alkaline solution cannot be immobilized on the polyimide. For this reason, white powder appears on the polyimide surface. In Patent Documents 2 and 3, as in Patent Document 1, alkali development is not performed, and the epoxy resin is used for improving chemical resistance and moisture resistance. It cannot be immobilized on polyimide. For this reason, white powder appears on the polyimide surface.

  Since this white powder is a hydrolyzate in an alkaline solution, it is possible to prevent the white powder from appearing by washing the alkaline solution causing hydrolysis with an acid after alkali development. However, the cleaning with an acid has a problem that the manufacturing process increases.

  Therefore, the inventors of the present application (Japanese Patent Application No. 2006-214837) contain a polyimide compound obtained by a reaction between an acid dianhydride and a diamine having a hydroxyl group, a photosensitive agent, and a crosslinking agent. The polyimide composition, the flexible wiring board, and the manufacturing method of a flexible wiring board which were characterized were completed.

  In the polyimide composition of the present invention, the hydrolyzate produced in the alkali development step (hereinafter referred to as alkali development) can be immobilized on the polyimide with a crosslinking agent, and the progress of hydrolysis by the alkaline solution can be stopped. It was possible to prevent the white powder from appearing on the polyimide surface even when alkaline development was performed.

  However, depending on the selection of the polyimide compound, the alkali solubility is not sufficient, and the sodium carbonate-based alkali solubility required from the environmental load is not sufficient.

  Moreover, when using a polyimide composition as a cover-lay material of a flexible wiring board, it was not enough about the low elasticity and flame retardance which are naturally required.

  The present inventors have conducted intensive research in view of such a new problem. Therefore, the present invention provides a polyimide composition that does not expose white powder without acid washing even after alkali development, and provides a flexible wiring board using the polyimide composition and a method for producing the same. This is the first purpose.

  In addition, the inventors have improved the alkali developability based on alkali solubility, in particular, a polyimide composition that enables sodium carbonate-based alkali developability, and a flexible wiring board using the polyimide composition and its production A second object is to provide a method.

  A third object is to provide a polyimide composition suitable as a coverlay material for a flexible wiring board, a flexible wiring board using the polyimide composition, and a method for producing the same.

  The polyimide composition of the present invention that achieves the above object comprises a polyimide compound obtained by a reaction between an acid dianhydride and a diamine having a hydroxyl group, a photosensitive agent, and a crosslinking agent. A polyimide composition, wherein the acid dianhydride comprises 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, and the diamine having a hydroxyl group is 3,3′-diamino-4,4 ′ -Dihydroxydiphenyl sulfone is included.

  Moreover, this invention is a flexible wiring board with a coverlay which used such a polyimide composition as a coverlay material of a flexible wiring board.

  In addition, the present invention uses such a polyimide composition as a coverlay material for flexible wiring boards, and also has a flexible coverlay that heats and cures a hydrolyzate of a polyimide compound that is generated when treated with an alkaline solution. It is a manufacturing method of a wiring board.

  In the polyimide composition of the present invention, the diamine component has a hydroxyl group and a photosensitizer so that a predetermined pattern can be formed by exposure and alkali development by immersion in an alkali solution.

  Here, although the hydrolyzate resulting from the alkali solution remains on the surface of the polyimide composition that has not been removed by the alkali development, the hydrolyzate generated by the alkali development is caused by the crosslinking agent contained in the polyimide composition. It can be immobilized on polyimide. Thereby, the progress of the hydrolysis by the alkaline solution can be stopped, and even if the alkali development is performed, the white powder can be prevented from appearing on the polyimide surface. That is, the polyimide composition of this invention can fix a hydrolyzate to a polyimide layer on a flexible wiring board.

  Furthermore, the polyimide compound of the present invention contains 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride as an acid dianhydride, and the diamine having a hydroxyl group is 3,3′-diamino-4, It is composed of 4'-dihydroxydiphenyl sulfone and has extremely high solubility in this alkaline solution.

  Furthermore, by including a siloxane diamine containing a phenyl group as a diamine component, high flame retardancy and low elasticity can be obtained, which is suitable as a coverlay material for a flexible wiring board.

  In the present invention, by having a photosensitive agent, a predetermined pattern can be formed by alkali development after exposure. The hydrolyzate produced by this alkali development can be immobilized on polyimide by reacting with a crosslinking agent, and the white powder can be prevented from being exposed. Therefore, even if alkali development is performed, it is possible to prevent the white powder from appearing without washing with an acid.

  Furthermore, by selecting a specific material for the acid dianhydride and diamine component that constitutes the polyimide compound, it is possible to increase alkali solubility, and further, low elasticity and flame resistance required as a coverlay material for flexible wiring boards Can be 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 that can prevent white powder from being generated on the surface by alkali development. This polyimide composition contains a polyimide compound obtained by a reaction between an acid dianhydride and a diamine having a hydroxyl group, a photosensitive agent, and a crosslinking agent.

  By including a photosensitizer in the polyimide composition, a pattern can be formed by performing alkali development after exposure. In general, polyimide compounds are susceptible to hydrolysis with respect to alkali. Polyimide hydrolysis is thought to go through a two-step process. In the first stage, the imide ring in the polyimide is opened, and the polyamic acid structure (fragile layer) and decomposition occur. Further, when an alkali is present, this amide skeleton is also hydrolyzed until the polymer chain is broken. If hydrolysis continues in this state, the molecular weight is eventually lowered, and it is considered that this low molecular weight component comes to the surface as “white powder”. In the alkali development stage, it is considered that hydrolysis to the first stage amide occurs (fragile layer formation). At this time, since the time of immersion in the alkali is relatively short, the molecular weight does not decrease. Therefore, no apparent film deterioration can be confirmed. However, it has been found in the wet heat aging test and the like that the invisible fragile layer eroded by alkali is accelerated by the aging conditions to produce white powder on the surface. In the present invention, by containing a cross-linking agent, the cross-linking agent reacts with the hydrolyzate of polyimide, and the immobilization on the polyimide becomes possible, thereby preventing the white powder from being exposed.

  In addition, the polyimide composition used as the coverlay material of the flexible wiring board does not require a high elastic modulus of 1 GPa or more, but rather siloxane diamine is used as a part of the diamine component of the polyimide compound in order to obtain low elasticity. The By using this siloxane diamine, the entire polyimide layer has a low elasticity, and as a result, it is rarely used for applications requiring a PCT test (pressure cooker test), but it does not completely eliminate hydrolysis.

  The acid dianhydrides used in the present invention include 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride. This DSDA can improve the alkali solubility of the polyimide to be 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.

  Other acid dinumerators used in the present invention include, for example, pyromellitic dianhydride (PMDA), 2,3,6,7-naphthalenetetracarboxylic dianhydride (NTCDA), 4,4′- (Hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,4,3 ′, 4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,4,3 ′, 4′-biphenyltetracarboxylic acid Anhydride (BPDA or s-BPDA), 4,4′-oxydiphthalic anhydride (ODPA), 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorene dianhydride (BPF-PA ), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, etc. It said aromatic acid dianhydride and alicyclic acid dianhydride.

  As the diamine that reacts with the acid dianhydride to form a polyimide compound, one having a hydroxyl group in the molecule is used in order to improve developability. In the invention of the prior application, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (BIS-AP-AF) was used from the viewpoint of improving the solubility of polyimide. A polyimide composition characterized by comprising 3,3′-diamino-4,4′-dihydroxydiphenylsulfone (BSDA) is used.

  Since this BSDA has a hydroxyl group and a sulfone group, it has a sulfur atom and an oxygen atom having a large electronegativity like DSDA, and as a result, exhibits high alkali solubility.

  When the polyimide composition of the present invention is used as a coverlay material for a flexible wiring board, a siloxane diamine represented by the following structural formula 1 is used as another diamine component.

In the structural formula 1, R ¹ and R ² are alkylene groups which may be substituted. Specific examples thereof include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Can be mentioned. Examples of the substituent include a lower alkyl group such as a methyl group and an ethyl group, and an aryl group such as a phenyl group. Of these, a trimethylene group is desirable because of the availability of raw materials. R ¹ and R ² may be the same or different from each other, but they are preferably the same because it is difficult to obtain raw materials.

  Moreover, in said Structural Formula 1, m is an integer of 1-30, Preferably it is 1-20, More preferably, it is an integer of 2-20. This is because it is difficult to obtain raw materials when m is 0, and when m exceeds 30, the raw materials are separated without being mixed with the solvent. On the other hand, n is an integer of 0 to 20, preferably 1 to 20, more preferably an integer of 1 to 10. This is because when n is 1 or more, a diphenylsiloxane unit excellent in flame retardancy is introduced, the flame retardancy is improved as compared with the case where it is not introduced, and when it exceeds 20, the contribution to low elasticity is small. It is to become.

  By having such a dimethylsilylene skeleton, preferable low elasticity is given to the coverlay layer formed of the polyimide composition layer of the present invention, and as a result, the warp of the flexible wiring board can be reduced.

  In particular, a polyimide composition using a siloxane diamine having a dimethylsilylene skeleton and a diphenylsilylene skeleton gives low elasticity and flame retardancy, and is suitable as a coverlay material for flexible wiring boards. Specific examples of such siloxane diamines include KF-8010 having a dimethylsilylene skeleton, X-22-9409 and X-22-1660B-3 having a dimethylsilylene skeleton and a diphenylsilylene skeleton (all manufactured by Shin-Etsu Chemical Co., Ltd.) Can be mentioned.

  BSDA in diamine is used in the range of 30-60 mol%. When the BSDA is 30 mol% or more, preferable alkali solubility is exhibited when used in combination with DSDA, and when it is within 70 mol%, moderate alkali solubility can be maintained and development conditions can be easily adjusted.

  On the other hand, the said siloxane diamine in diamine is used in 40-70 mol%. If it is 40% or more, there is an effect that warpage can be kept low.

  In addition, although the siloxane diamine having only the dimethyldisilylene skeleton tends to decrease in flame retardancy as the mol% in the diamine increases, the siloxane diamine having a diphenylsilylene skeleton has a small effect on the flame retardancy. . Any siloxane diamine has an effect of not affecting the flame retardancy while maintaining the effect of low warpage as long as it is within 70 mol%.

  By the way, the solubility to an alkaline solution improves by using the diamine which has a hydroxyl group as a monomer of a polyimide. In the present invention, as described below, a photosensitive agent is used to impart alkali solubility to the exposed part. However, in the unexposed part, part of the polyimide is hydrolyzed by the alkaline solution. It will be decomposed and white powder will be exposed on the polyimide surface.

  Here, the influence of the alkali solution on the polyimide using the diamine having a hydroxyl group will be described. First, polyimides respectively formed using the BIS-AP-AF and PMDA or BPDA were formed into a film. As a comparison, a polyimide formed using 2,2′-bistrifluoromethyl-4,4′-diaminobiphenyl (TFMB) and PMDA or BPDA, respectively, was formed into a film. And the infrared absorption spectrum before and behind immersion to the alkaline solution of these four types of polyimide films was measured. The immersion in the alkaline solution was performed at room temperature, and a 3 wt% sodium hydroxide solution was used, and the immersion was performed for a predetermined time in this solution. And the polyimide film immersed in the alkaline solution was washed with distilled water and dried, and then the infrared absorption spectrum was measured. The infrared absorption spectrum of polyimide by BIS-AP-AF and PMDA is shown in FIG. 1, the infrared absorption spectrum of polyimide by BIS-AP-AF and BPDA is shown in FIG. 2, and the red color of polyimide by TFMB and PMDA. The external absorption spectrum is shown in FIG. 3, and the infrared absorption spectrum of polyimide by TFMB and BPDA is shown in FIG.

As a result, the polyimide film using BIS-AP-AF having a hydroxyl group has no peaks (1778 cm ⁻¹ and 1730 cm ⁻¹ ) indicating imide carbonyl as shown in FIG. 1 and FIG. 2 and is immersed in an alkaline solution. It was found that imidocarbonyl disappeared. The same results were obtained with a polyimide film using BSDA. On the other hand, as for the polyimide film using TFMB which does not have a hydroxyl group, the change of the spectrum was not seen before and after immersion in an alkaline solution like FIG.3 and FIG.4. Thus, it was found that by using a diamine having a hydroxyl group, hydrolysis of polyimide by an alkaline solution occurred, and white powder was exposed on the surface. In the present invention, a hydrolyzate produced by alkali development of a polyimide using a diamine having a hydroxyl group is reacted with a crosslinking agent to be immobilized on the polyimide, thereby preventing the appearance of white powder.

  As diamines having similar effects, 4,4′-diamino-3,3′-biphenyldiol (HAB), 9,9-bis (3-amino-4-hydroxyphenyl) fluorene (BAHF), 3,3 ′ -Diamino-4,4'-dihydroxydiphenylsulfone (BSDA) or the like can also be used, but at least BSDA is used in the present invention as a combination that does not impair the alkali developability and the effect of the siloxane diamine used together.

  The polyimide compound contained in the polyimide composition is obtained by dissolving the above acid dianhydride and diamine in a solvent such as N-methyl-2-pyrrolidone (NMP), triethylene glycol dimethyl ether (triglyme), or γ-butyrolactone. The acid dianhydride and the diamine in the solvent are subjected to addition polymerization, and then formed by a cyclization dehydration reaction (heat imidization in a solution or chemical imidation with a dehydrating agent). Add an azeotropic agent such as toluene or xylene into the polyimide precursor and heat and stir to 180 ° C. or higher to dehydrate the polyamic acid component to form a polyimide component in which part or all of the polyamic acid is closed. . At this time, if necessary, a tertiary amine such as triethylamine, a basic catalyst such as aromatic isoquinoline, pyridine, or an acid catalyst such as benzoic acid or parahydroxybenzoic acid may be added as a catalyst for imidation. These compounds may be used alone or a plurality of compounds may be used in combination. The polyamic acid can also be ring-closed by a chemical imidizing agent such as acetic anhydride / pyridine or dicyclohexylcarbodiimide which is a dehydrating cyclization reagent.

  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 its alkali solubility upon exposure. Before exposure, the solubility in an alkaline aqueous solution is low. On the other hand, after exposure, the molecular structure of the diazonaphthoquinone compound changes to produce ketene, which reacts with water to produce carboxylic acid. And the produced | generated carboxylic acid further reacts with alkaline aqueous solution, and melt | dissolves. Therefore, the solubility in alkaline aqueous solution becomes high by irradiating light.

  By containing a diazonaphthoquinone compound as a photosensitizer, a polyimide compound having a hydroxyl group and relatively high alkali solubility has a hydrogen bond between the hydroxyl group and the diazonaphthoquinone compound. 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 amount of the photosensitive composition contained in the polyimide composition is preferably 10 to 30 parts by weight with respect to 100 parts by weight of the polyimide compound. Moreover, the expression of white powder is suppressed by using together with the crosslinking agent demonstrated below.

  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 functional groups (for example, epoxy groups). This cross-linking agent can cause an addition reaction with a hydrolyzate of a polyimide compound after alkali development with an alkali solution at a relatively low temperature such as about 200 ° C., thereby immobilizing the hydrolyzate on the polyimide. Specifically, a hydrolyzate having an amino group or a carboxylic acid group at the terminal is generated from the polyimide compound by an alkaline solution. The cross-linking agent has a plurality of functional groups, and this functional group reacts with an amino group or a carboxyl group, and the broken bond is re-bonded by the cross-linking agent to fix the hydrolyzate to the polyimide. Thereby, it can prevent that a hydrolyzate expresses on the polyimide surface as white powder. As a functional group of this crosslinking agent, an epoxy group or a maleimide group is preferable. If it is a functional group having a plurality of epoxy groups or maleimide groups, it can be reacted with a hydrolyzate having an amino group or a carboxyl group at a relatively low temperature, and heating to other members even when used for flexible wiring boards Can reduce the influence of.

  Moreover, the adhesiveness between conductors, such as copper foil, and a polyimide can be improved with this crosslinking agent.

  As a quantity which makes this polyimide composition contain this crosslinking agent, it is preferable that it is 20 weight part or less with respect to 100 weight part of polyimide compounds. When the crosslinking agent is contained in an amount of 20 parts by weight or more, the stability of the polyimide composition is deteriorated and the viscosity is increased, so that the handling of the polyimide composition is deteriorated. Moreover, since photosensitivity falls, alkali development becomes difficult. In addition, since epoxy groups may also be hydrolyzed by an alkaline aqueous solution, it is desirable to add 1 part by weight or more in order to maintain the crosslinking effect, and further, the amount of the polyimide composition containing this crosslinking agent. More preferably, it is 5 to 10 parts by weight. By including the amount in this range in the polyimide composition, it is possible to prevent the white powder from appearing and to prevent the formed polyimide surface from deteriorating.

  The crosslinking agent having an epoxy 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 bis-type epoxy compounds, bis-A type epoxy compounds, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate and other alicyclic epoxy compounds, sorbitol polyglycidyl ether, poly Glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether , Hydrogenated bisphenol A diglycidyl ether, polyethylene glycol glycidyl ether, polypropylene glycol diglycidyl Glycidyl ether compounds such as ether, hydroquinone diglycidyl ether, glycidyl ester compounds such as diglycidyl phthalate and glycidyl terephthalate, halogenated flame retardant epoxy compounds such as dibromoneopentylglycol glycidyl ether, cresol novolac epoxy resin And phenol novolac epoxy resins.

  Examples of the crosslinking agent having a maleimide group as a functional group include 4,4′-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5. Examples include '-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide and the like.

  The polyimide composition may contain an oxazine compound. In the oxazine compound, the oxazine skeleton in the molecule is opened by heat and cured. By containing this oxazine compound in the polyimide composition of the present invention, it acts as a crosslinking agent, and the flame retardancy and adhesion to a metal such as copper can be improved in the polyimide composition. The addition amount may be as small as 5 parts by weight or less with respect to 100 parts by weight of the polyimide compound, for example.

  Examples of the oxazine compound include bisphenol F-type benzoxazine (6,6 ′-(1-methylidene) bis [3,4-dihydro-3-phenyl-2H-1,3-benzoxazine]), bisphenol S-type. Benzoxazine (6,6′-sulfonylbis [3,4-dihydro-3-phenyl-2H-1,3-benzoxazine]), bisphenol A type benzoxazine (the following structural formula 2), phenol novolac type benzoxazine ( The following structural formula 3) and the like can be mentioned.

  The polyimide composition may contain a rust preventive agent. Examples of the rust preventive include 2,3-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] propionohydrazide (CDA-), which is a hydrazide-based metal deactivator. 10), and when used for a flexible wiring board, resin deterioration of the polyimide composition in contact with the metal can be prevented.

  Examples of rust preventives other than CDA-10 include decamethylenecarboxylic acid disalicyloyl hydrazide as hydrazide-based compounds, and 3- (N-salicyloyl) amino-1,2,4-triazole as triazole-based compounds. However, it is not limited to these.

  The polyimide composition of the present invention can be formed by adding a photosensitizer and a crosslinking agent to a solution in which a polyimide composition synthesized by polymerization of DSDA, BSDA, and siloxane diamine is dissolved in NMP, GBL or the like. .

  And after evaporating the solvent in this polyimide composition, by exposing, the structure of the photosensitive agent in a polyimide composition is changed, and the alkali solubility of the location which performed exposure is improved. And the location which exposed was removed by being immersed in an alkaline solution, and a predetermined pattern (positive pattern) is formed.

  An alkaline solution remains on the surface of the polyimide composition on which the positive pattern is formed. This alkaline solution hydrolyzes the polyimide compound to produce a hydrolyzate having an amino group or a carboxyl group. At this time, a crosslinking agent reacts with an amino group or a carboxyl group, and a hydrolyzate is fixed to polyimide. Moreover, after immersing in an alkaline solution, reaction of a crosslinking agent and a hydrolyzate can be accelerated | stimulated by heating a polyimide composition, and a hydrolyzate can fully be fixed to a polyimide.

  Therefore, it can prevent that a hydrolyzate becomes white powder and it exposes on the polyimide surface. Therefore, it is possible to produce a polyimide composition that does not generate white powder even when alkali development is performed.

  This polyimide composition can be used for a flexible wiring board as shown in FIG. In this case, the polyimide composition is applied by a known coating method so as to cover the conductor 4 such as copper formed on the base material 2 so as to have a predetermined pattern. Then, the polyimide composition is dried to form the polyimide layer 3 (uncured state) on the conductor 4. The flexible wiring board 1 is provided with a mask layer that exposes light to a portion of the polyimide layer 3 to be removed, and after exposure, alkali development is performed by immersion in an alkaline solution, and the polyimide layer 3 is sufficiently heated. By setting the cured state, the flexible wiring board 1 having the polyimide layer 3 on which a predetermined positive pattern is formed is obtained. In the present invention, the cured state means that the polyimide skeleton is completely crosslinked by the crosslinking agent by heating the polyimide layer, and the uncured state is a state that has not yet reached the cured state. It is.

  The polyimide layer 2 left on the flexible wiring board 1 without being removed by alkali development fixes the hydrolyzate produced by the alkaline solution to the polyimide by a crosslinking agent. Therefore, it is possible to produce a flexible wiring board that does not generate white powder even when alkali development is performed. By heating the flexible wiring board 1 after alkali development, the reaction between the crosslinking agent and the hydrolyzate can be promoted, and the hydrolyzate can be sufficiently immobilized. At this time, since the reaction of the crosslinking agent proceeds at a relatively low temperature, the influence on other members due to heating at a high temperature can be reduced.

  Moreover, the flexible wiring board 1 using this polyimide composition can form a predetermined positive pattern by alkali development after exposure, and becomes a wiring board free from white powder. And by using this wiring board for an electronic component, a highly reliable electronic component can be provided.

[Example]
(Preparation of polyimide composition)
[Example 1]
137.47 g (100.48 mmol) of siloxane diamine X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd.), 16.41 g (purity 99.5%, 58.26 mmol) of BSDA was added to Dean-Stark. The solution was put into a 500 ml four-necked separable flask attached and completely dissolved with 238.5 g of N-methylpyrodon under a nitrogen atmosphere. Thereafter, 57.62 g (purity 99.7%, 160.33 mmol) of DSDA was added, and after stirring at 80 ° C. for 2 hours, 70 ml of toluene, an azeotropic agent for removing imidized condensed water, was added, The mixture was stirred and refluxed at 180 ° C. for 5 hours in a bath to obtain the desired product.

  15 parts by weight of a diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) and a bismaleimide-based crosslinking agent (BMI-4000, Yamato) with respect to 100 parts by weight of the solid content of the obtained polyimide compound solution 10 parts by weight of Kasei Kogyo Co., Ltd. was added to complete the target polyimide composition.

[Example 2]
143.34 g (104.78 mmol) of siloxane diamine X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd.), 18.71 g (purity 99.5%, 66.41 mmol) of BSDA was added to Dean-Stark. The solution was put into a 500 ml four-necked separable flask attached and completely dissolved with 229.5 g of N-methylpyrodon under a nitrogen atmosphere. Then, 58.45 g (purity 99.7%, 162.65 mmol) of DSDA was added and stirred at 80 ° C. for 2 hours, and then 70 ml of an azeotropic agent toluene for removing imidized condensed water was added to the oil bath. The mixture was stirred and refluxed at 180 ° C. for 5 hours to obtain the desired product.

  15 parts by weight of a diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) and a bismaleimide-based crosslinking agent (BMI-4000, Yamato) with respect to 100 parts by weight of the solid content of the obtained polyimide compound solution 10 parts by weight of Kasei Kogyo Co., Ltd. was added to complete the target polyimide composition.

[Example 3]
106.41 g (77.78 mmol) of siloxane diamine X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd.), 25.72 g (purity 99.5%, 91.30 mmol) of BSDA was added to Dean-Stark. The solution was put into a 500 ml four-necked separable flask attached and completely dissolved with 256.5 g of N-methylpyrodon under a nitrogen atmosphere. Thereafter, 61.37 g (purity 99.7%, 170.77 mmol) of DSDA was added, and the mixture was stirred at 80 ° C. for 2 hours, and then 70 ml of an azeotropic agent toluene for removing imidized condensed water was added to the oil bath. The mixture was stirred and refluxed at 180 ° C. for 5 hours to obtain the desired product.

  15 parts by weight of a diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) and a bismaleimide-based crosslinking agent (BMI-4000, Yamato) with respect to 100 parts by weight of the solid content of the obtained polyimide compound solution 10 parts by weight of Kasei Kogyo Co., Ltd. was added to complete the target polyimide composition.

[Example 4]
121.31 g (88.67 mmol) of siloxane diamine X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd.), 31.16 g (purity 99.5%, 110.61 mmol) of BSDA attached to Dean-Stark The solution was poured into a 500 ml four-necked separable flask and completely dissolved with 229.5 g of N-methylpyrodon under a nitrogen atmosphere. Then, 68.03 g (purity 99.7%, 189.30 mmol) of DSDA was added and stirred at 80 ° C. for 2 hours, and then 70 ml of an azeotropic agent toluene for removing imidized condensed water was added to the oil bath. The mixture was stirred and refluxed at 180 ° C. for 5 hours to obtain the desired product.

  15 parts by weight of a diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) and a bismaleimide-based crosslinking agent (BMI-4000, Yamato) with respect to 100 parts by weight of the solid content of the obtained polyimide compound solution 10 parts by weight of Kasei Kogyo Co., Ltd. was added to complete the target polyimide composition.

[Example 5]
15 parts by weight of diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) and bis-F type epoxy resin (807, Japan) with respect to 100 parts by weight of the solid content of the polyimide compound solution obtained in Example 1 5 parts by weight of Epoxy Resin Co., Ltd.) was added to complete the target polyimide composition.

[Comparative Example 1]
137.44 g (100.46 mmol) of siloxane diamine, X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd.), 18.98 g (purity 99.0%, 51.30 mmol) of BIS-AP-AF was added to Dean. -It was put into a 500 ml four-necked separable flask equipped with Stark, and completely dissolved with 238.5 g of N-methylpyrodon under a nitrogen atmosphere. Thereafter, 55.08 g (purity 99.7%, 153.27 mmol) of DSDA was added and stirred at 80 ° C. for 2 hours, and then 70 ml of an azeotropic agent toluene for removing imidized condensed water was added to the oil bath. The mixture was stirred and refluxed at 180 ° C. for 5 hours to obtain the desired product.

  15 parts by weight of a diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) and a bismaleimide-based crosslinking agent (BMI-4000, Yamato) with respect to 100 parts by weight of the solid content of the obtained polyimide compound solution 10 parts by weight of Kasei Kogyo Co., Ltd. was added to complete the target polyimide composition.

[Comparative Example 2]
15 parts by weight of diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) is added to 100 parts by weight of the solid content of the polyimide compound solution obtained in Comparative Example 1, and the target polyimide composition is obtained. Completed.

[Comparative Example 3]
15 parts by weight of diazonaphthoquinone photosensitizer (4NT-300, manufactured by Toyo Gosei Co., Ltd.) is added to 100 parts by weight of the solid content of the polyimide compound solution obtained in Example 1, and the target polyimide composition is added. Was completed.

(Confirm development)
The polyimide compositions of Examples 1 to 4 and Comparative Example 1 were applied to one side of a copper foil that had been subjected to a chemical polishing treatment corresponding to 0.3 μm in advance to a thickness of 10 μm, and dried at 80 ° C. for 10 minutes.

Next, an ultrahigh pressure mercury lamp is exposed with a cumulative light amount of 2500 mJ / cm ² through a positive mask for resolution evaluation (300 μm / 300 μm line & space pattern), and 3 wt% sodium hydroxide 40 ° C. aqueous solution or sodium carbonate The substrate was immersed in a 1 wt% 40 ° C. aqueous solution and then immersed in warm water at 40 ° C. for 2 minutes for alkali development. Thereafter, it was thoroughly washed with distilled water and dried to complete a series of development processes. The developability was evaluated by the minimum immersion time when a 300 μm / 300 μm line & space was opened. In addition, it is so suitable that immersion time is short.

  As shown in Table 1, the BSDA polyimide compositions of Examples 1 to 4 can be alkali-developed in a short time of 30 seconds or less. Moreover, about Example 4, it can develop also with respect to sodium carbonate type aqueous alkali solution, and the improvement of workability | operativity can be anticipated. On the other hand, when Example 1 and Comparative Example 1 are compared, it can be seen that BIS-AP-AF type polyimide has a longer development time than BSDA type polyimide and has poor workability.

(White powder confirmation test)
Copper pattern for evaluation (TEG) (35 μm / 35 μm line and space pattern) base obtained by subjecting the polyimide compositions of Examples 1 to 4 and Comparative Examples 1 to 3 to a chemical polishing treatment equivalent to 0.3 μm in advance It was applied on the material so as to have a thickness of 10 μm and dried at 80 ° C. for 10 minutes to form a cover layer.

Next, an ultra-high pressure mercury lamp is exposed through a positive mask with an integrated light amount of 2500 mJ / cm ² and immersed in a 3 wt% sodium hydroxide 40 ° C. aqueous solution for the immersion time evaluated in “Confirmation of developability”. Alkali development was performed by immersing in warm water at 40 ° C. for 2 minutes. Thereafter, it was thoroughly washed with distilled water and dried to complete a series of development processes. The TEG with the cover layer was post-baked at 200 ° C. for 1 hour and then allowed to cool.

  Wiring was connected to the obtained TEG, and an ion migration test was performed for 1000 hours by applying 30 V in an environment of 85 ° C. and 85%.

  In Examples 1 to 5 and Comparative Example 1, it can be seen that generation of white powder can be suppressed by adding bismaleimide (BMI-4000) or an epoxy resin (Bis-F type) as a crosslinking agent.

  In Table 1, the composition of the dicarboxylic acid component and the diamine component of the polyimide compounds synthesized according to Examples 1 to 5 and Comparative Examples 1 to 3 and the numerical values corresponding thereto are displayed. Are all components (ie, DSDA, X-22-9409, BSDA, and BIS-) when all diamine components (X-22-9409, BSDA and BIS-AP-AF) are combined to make 100 moles. AP-AF).

(Flame retardance)
The polyimide composition of Example 1 was coated on a flat 25 μm-thick polyimide film (Upilex 25S, Ube Industries, Ltd.) so that the dry thickness was 10 μm, and dried at 80 ° C. for 10 minutes. Subsequently, it heated at 200 degreeC under nitrogen atmosphere for 1 hour, and bridge | crosslinking of the polyimide composition was completed. When the combustion test of the obtained polyimide film piece was performed, UL-94-VTM-0 was satisfied.

It is an infrared absorption spectrum of polyimide by BIS-AP-AF and PMDA. It is an infrared absorption spectrum of polyimide by BIS-AP-AF and BPDA. It is an infrared absorption spectrum of polyimide by TFMB and PMDA. It is an infrared absorption spectrum of polyimide by TFMB and BPDA. It is sectional drawing of the flexible wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible wiring board 2 Base material 3 Polyimide layer 4 Conductor

Claims (8)

A polyimide compound obtained by reacting an acid dianhydride with a diamine having a hydroxyl group;
A photosensitizer,
A polyimide composition comprising a crosslinking agent,
The acid dianhydride comprises 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride,
A polyimide composition, wherein the diamine having a hydroxyl group comprises 3,3′-diamino-4,4′-dihydroxydiphenylsulfone. Diamine has the following structural formula 1
(In the structural formula 1, m is an integer of 1 or more, n is 0 or an integer of 1 or more, and R ¹ and R ² are each independently an optionally substituted alkylene group) The polyimide composition according to claim 1, comprising a siloxane diamine.   The polyimide compound according to claim 1, wherein the crosslinking agent has a plurality of epoxy groups or maleimide groups.   The polyimide composition according to claim 1, wherein the crosslinking agent is contained in an amount of 20 parts by weight or less based on the polyimide compound.   The polyimide composition according to claim 1, wherein the crosslinking agent is contained in an amount of 5 parts by weight or more and 10 parts by weight or less based on the polyimide compound.   A flexible wiring board with a coverlay, comprising a conductor and a polyimide composition layer formed by applying the polyimide composition according to any one of claims 1 to 5. Adjusting the polyimide composition according to any one of claims 1 to 5,
Applying the polyimide composition to a conductor to form a polyimide layer;
And a step of forming a predetermined pattern by exposing the polyimide layer to the alkaline solution after exposure.   The flexible wiring with coverlay according to claim 7, wherein after the treatment with an alkaline solution, the hydrolyzate generated by hydrolysis of the polyimide compound with the alkaline solution is reacted with the crosslinking agent by heating. A manufacturing method of a board.