JPH04222862A - Polyimide resin composition, prepreg and laminate thereof - Google Patents

Abstract

PURPOSE:To obtain a polyimide resin composition and prepreg thereof capable of producing laminates having excellent through-hole reliability and low dielectric constant, comprising a polyimide resin, diallyl phthalate, a promoter, a solvent, etc. CONSTITUTION:A resin composition comprising (A) 100 pts.wt. polyimide resin obtained by reacting an unsaturated bis-imide (e.g. maleic acid N,N-ethylene- bis-imide) with a diamine (4,4-diaminodicyclohexylmethane) containing >=11wt.% preferably at least one of alkyl and alkylene except methylene in the polyimide resin, (B) 20-200 pts.wt. diallyl phthalate, (C) a promoter (e.g. imidazole), a diluting solvent (e.g. dimethylformamide), etc., and preferably for flame retardance (D) 1-50 pts.wt. calculated as bromine content of a reactive group- containing brominated resin (preferably brominated epoxy resin), prepreg thereof and a laminate obtained therefrom.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a polyimide resin composition used for printed wiring boards, etc., a polyimide resin prepreg using this resin composition, and a polyimide resin laminate obtained by curing this prepreg. be.

0002

2. Description of the Related Art Polyimide resins and epoxy resins have been widely used as resins for laminated boards and the like. Among these, polyimide resins have been widely used in highly multilayer wiring boards for high-density packaging, as described in Japanese Patent Laid-Open Nos. 59-20659 and 61-40322.

However, in recent years, the dielectric constant of polyimide resin laminates has been reduced in order to increase the propagation speed of electrical signals in response to the increasing speed of computers and other electromechanical devices using semiconductor devices. As the number of layers increases, there is a strong desire to prevent penetration of through-hole plating in order to improve reliability, and to improve safety.

0004

[Problems to be Solved by the Invention] The present invention aims to reduce the dielectric constant of a laminate in order to adapt to higher propagation speeds of electrical signals, and to improve the through-hole reliability of resin base materials. A polyimide resin composition that can ensure good impregnability, prevent penetration of through-hole plating, and further improve safety due to flame retardancy, a prepreg thereof,
and to provide a laminate thereof.

[0005]

[Means for Solving the Problems] The present invention has been made in view of the above points. The present inventors conducted research on reducing the dielectric constant of commonly known addition-type polyimide resins, and as a result, discovered a chemical structure effective for lowering the dielectric constant and its quantitative contribution. In addition, it has been found that when a predetermined amount of diallyl phthalate (hereinafter referred to as DAP) is blended, the dielectric constant further decreases. Furthermore, when DAP is used, the intrinsic viscosity of the resin is reduced, and the impregnation of the resin into the base material is improved, making it possible to obtain a homogeneous and stable prepreg. We have discovered a polyimide resin composition and its prepreg that can be used to produce laminates. Furthermore, by blending a predetermined amount of brominated resin with reactive groups, it does not cause side effects such as reduced adhesion or heat resistance, and has flame retardant, low dielectric constant, and excellent through-hole reliability. We have discovered a polyimide resin composition and its prepreg that can be used to produce laminates.

The polyimide resin composition contains 1) polyimide resin, 2) 2 parts by weight based on 100 parts by weight of the polyimide resin.
DAP blended in an amount ranging from 0 to 200 parts by weight,
3) It is characterized by comprising an accelerator, a solvent, etc. Furthermore, in order to obtain flame retardancy, a bromine content range of 1 to 50 parts by weight is added to 100 parts by weight of the polyimide resin. It is characterized by containing a brominated resin having a reactive group.

[0007] Furthermore, polyimide resin prepreg has 1
) a polyimide resin, 2) DAP blended in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the polyimide resin, 3) a polyimide resin composition consisting of an accelerator, a solvent, etc. as a base material. It is characterized by being impregnated and semi-cured, and furthermore, in order to obtain flame retardance, it has a reactive group in the range of 1 to 50 parts by weight of bromine per 100 parts by weight of the polyimide resin. It is characterized by containing a brominated resin.

[0008] The polyimide resin laminate also contains 1) a polyimide resin, 2) DAP blended in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the polyimide resin, 3) and an accelerator. , a base material is impregnated with a polyimide resin composition consisting of a solvent, etc., and one or more sheets of semi-cured prepreg are laminated and cured. is characterized in that it contains a brominated resin having a reactive group in an amount of 1 to 50 parts by weight based on bromine content per 100 parts by weight of a polyimide resin.

[0009] These will be explained in detail below. Polyimide resins can be obtained by reacting unsaturated bis-imides with diamines and the like. In the polyimide resin obtained in this way, at least one of an alkyl group or an alkylene group other than a methylene group is added to the polyimide resin.
The content is preferably 1% by weight or more. This is because if the chemical structure includes less than 11% by weight of alkyl groups or alkylene groups other than methylene groups in the resin molecule, the dielectric constant of the polyimide resin cannot be lowered.

The unsaturated bis-imide is represented by (a) in Chemical Formula 1 at the end of the specification, in which D represents a divalent group containing a carbon-carbon double bond, and A represents at least two Diamines are represented by the following formula (b), and B in formula (b) is a divalent group having 30 or less carbon atoms. Can be used. H2 NB-NH2 (b
) Furthermore, are A in formula (a) and B in formula (b) the same?
or a straight-chain or branched alkylene group having fewer than 13 carbon atoms or a cyclic alkylene group having 5 or 6 carbon atoms in the ring, O,N and a heterocyclic group containing at least one S atom, or a phenylene or polycyclic aromatic group. These various groups may have substituents that do not cause unnecessary side reactions under the reaction conditions of a reaction temperature of 70 to 170°C and a reaction time of 30 to 350 minutes.

A in formula (a) and B in formula (b) also represent a number of phenylene groups or alicyclic groups bonded directly or by divalent atoms or groups such as You can also do that. For example, are they oxygen or sulfur?
An alkylene group of 1 to 3 carbon atoms or one of the following groups:

-NR4 -, -P(O)R3 -, -N
=N-, -O=N-, -CO-O-, -CONH-
, -SiR3 R4-, -NY-CO-X-CO-
NY-, -O-CO-X-CO-O-, -SO2 -,
and one of the group (c) of chemical formula 1 at the end of the specification. In these formulas, R3, R4 and Y each have 1 to 4 carbon atoms, and 5 or 6 carbon atoms in the ring.
represents a cyclic alkyl group having 5 or 6 carbon atoms, or a phenyl or polycyclic aromatic group, where X is a linear or branched alkylene group having fewer than 13 carbon atoms, represents a cyclic alkylene group having 5 carbon atoms, or a monocyclic or polycyclic arylene group.

The group D in formula (a) above is derived from the ethylene anhydride of chemical formula 1 (d) at the end of the specification, such as maleic anhydride, citraconic anhydride,
It can also represent tetrahydrophthalic anhydride, itaconic anhydride, and the product of a Diels-Alder reaction between a cyclodiene and one of these anhydrides.

Preferred unsaturated bis-imides of formula (a) that can be used include:

Maleic acid N·N-ethylene-bis-imide, maleic acid N·N-hexamethylene-bis-imide, maleic acid N·N-metaphenylene-bis-imide,
Maleic acid N.N-paraphenylene-bis-imide, maleic acid N.N-4.4-diphenylmethane-bis-imide [usually also referred to as N.N-methylenebis (N-phenylmaleimide)], maleic acid N.・N-4・4-
Diphenyl ether bis-imide, maleic acid N/N
-4,4-diphenylsulfone-bis-imide, maleic acid N・N-4,4-dicyclohexylmethane-bis-imide, maleic acid N・N-α・α-4,4-dimethylenecyclohexane-bis-imide , maleic acid N・N
- metaxylylene-bis-imide, maleic acid N/N-
Diphenylcycloxane-bis-imide, 1,3-bis(2-p-anilinopropylidene)benzene-bis-imide, 1,4-bis(2-p-anilinopropylidene)
Benzene-bis-imide, 1,4-bis(2-m-anilinopropylidene)benzene-bis-imide, 4,4-
Methylenedi-2,6-xylidine-bis-imide, 4.
4-methylenedi-2,6-diethylaniline-bis-imide, 4,4-diamino-3,3-diethyl-5,5-
Dimethyldiphenylmethane-bis-imide, 4,4-methylenedi-2,6-diisopropylaniline-bis-imide, 2,5-dimethyl-p-phenylenediamine-bis-imide, 2,2-bis(4-aminophenyl) Propane-bis-imide, 2,4-diaminomesitylene-bis-imide, 3,5-diethyl-2,4-tolylenediamine-bis-imide, and the like.

Examples of diamines of formula (b) that can be used include the following: 4,4-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, 2,6-diaminopyridine, metaphenynediamine, paraphenynediamine, 4,4-diaminodiphenylmethane, 2,2-bis-(4-aminophenyl) ) Propane, benzidine, 4,4-diaminophenyl oxide, 4,4-diaminodiphenyl sulfide, 4,4-
Diaminodiphenylsulfone, bis-(4-aminophenyl)diphenylsilane, bis-(4-aminophenyl)methylphosphine oxide, bis-(3-aminophenyl)methylphosphine oxide, bis-(4-
(aminophenyl) phenylphosphine oxide, bis-(4-aminophenyl) pheniramine, 1,5-diaminonaphthalene, meta-xylylene diamine, para-xylylene diamine, 1,1-bis-(para-aminophenyl)
Phthalane, hexamethylene diamine, 1,3-bis(2
-p-anilinopropylidene)benzene, 1,4-bis(2-p-anilinopropylidene)benzene, 1,4-
Bis(2-m-anilinopropylidene)benzene, 4.
4-methylenedi-2,6-xylidine, 4,4-methylenedi-2,6-diethylaniline, 4,4-diamino-
3,3-diethyl-5,5-dimethyldiphenylmethane, 4,4-methylenedi-2,6-diisopropylaniline, 2,5-dimethyl-p-phenylenediamine, 2.
2-bis(4-aminophenyl)propane, 2,4-diaminomesitylene, and 3,5-diethyl-2,4
-Tolylene diamine etc.

An addition type polyimide resin can be prepared by reacting the above bis-imide with a diamine. The molar ratio of bis-imide and diamine is 1 part bis-imide to 1 part diamine.
The range of 7 to 2.5 is preferable. If the bis-imide content is less than 1.7, the production of high molecular weight increases, resulting in a short curing time, which tends to cause problems in handling, while if the bis-imide content is more than 2.5, a large amount of unreacted raw material remains. It becomes easier to do. The reaction involves combining bis-imide and diamine with N-methylpyrrolidone (NMP) or N,N-dimethylacetamide (DM).
It can be carried out in a state dissolved in a solvent such as Ac), and the heating temperature during the reaction can be carried out in the range of about 70 to 170°C, and the reaction time can be carried out in the range of about 30 to 350 minutes. be able to.

The polyimide resin composition of the present invention contains DA in 100 parts by weight (hereinafter referred to as parts) of the polyimide resin.
P is blended in an amount ranging from 20 to 200 parts, and further,
Imidazole and organic peroxides are used as accelerators, and dimethylformamide (DMF) and DMA are used as diluting solvents.
It is a resin composition consisting of one or a mixture of one or more of the following: c, dioxane, NMP, MEK, etc. As the amount of DAP added increases, the dielectric constant of the resulting laminate tends to decrease; when less than 10 parts is added, there is almost no effect of lowering the dielectric constant, and when more than 200 parts are used, the dielectric constant decreases. The rate decreases, but it is hard as a laminate,
This is not desirable as it becomes brittle. Furthermore, since DAP also acts as a reactive diluent, it lowers the intrinsic viscosity and surface tension of the resin composition. Therefore, the resin composition penetrates well between the fibers of the base material, and it is possible to obtain a prepreg in which the filling of the resin into the base material is significantly improved. In the laminates cured with this prepreg, the penetration length of the through-hole plating is significantly shortened, and at the same time, the inner walls of the through-holes are finished extremely smooth, which improves the insulation between the through-holes and the inner layer circuits. Effects such as ensuring properties and significantly improving the reliability of the through hole can be obtained.

In order to ensure the flame retardancy required for the safety of electronic mechanical devices, it is preferable to blend a brominated resin having a reactive group as a flame retardant into the polyimide resin composition. The blending amount of the brominated resin having a bromine content is 1 to 5 by weight based on 100 parts by weight of the polyimide resin.
It is preferable to use it in a range of 0 parts by weight. The reason is 1.
If the amount is less than 50 parts by weight, flame retardancy cannot be obtained, and if the amount exceeds 50 parts by weight, the heat resistance of the resulting laminate will be poor and the dielectric constant will also increase, resulting in decreased performance. Furthermore, brominated resins having reactive groups are preferable because the flame retardant is reacted with the side chains and terminal groups of the polyimide resin, and is incorporated into the skeleton of the polyimide resin structure. This is because it is possible to obtain a product that combines reliability, heat resistance, and flame retardant performance.

[0020] Therefore, as a reactive group, an epoxy group,
Alkyl of 1 to 4 carbon atoms with allyl group, vinyl group, etc., cyclic alkyl with 5 or 6 carbon atoms in the ring, or phenyl or polycyclic aromatic, or less than 13 carbon atoms A brominated resin such as a linear or branched alkylene having atoms, a cyclic alkylene having 5 or 6 carbon atoms in the ring, or a monocyclic or polycyclic arylene can be used as appropriate. In particular, an epoxy group can be mentioned as a preferable reactive group since it maintains or improves heat resistance and interlayer adhesive strength.

To obtain a prepreg from the above polyimide resin composition, after impregnating the base material with the above polyimide resin composition, the polyimide resin and DAP, which is a reactive diluent, are mixed together while drying and evaporating the diluting solvent. It is obtained by allowing the reaction to proceed and semi-curing the resin composition in the base material. Furthermore, the reactive brominated resin contained in order to obtain flame retardancy reacts with the side chains and terminal groups of the polyimide resin during the preparation of this prepreg, and is incorporated into the skeleton of the polyimide resin structure. .

The type of substrate impregnated with the polyimide resin composition is not particularly limited. Usually, glass cloth or the like is used. In addition, inorganic fiber cloths such as quartz fiber cloths, nonwoven fabrics thereof, and highly heat-resistant organic fiber cloths such as polyimide resin fiber cloths and nonwoven fabrics may be used.

[0023] The temperature during semi-curing is 110 to 155
Preferably, it is carried out at °C. When the temperature exceeds 155°C, the reaction of DAP in particular progresses too much, the interlayer adhesive strength of the obtained prepreg decreases, and the effect of decreasing the dielectric constant becomes small.
This is because if the temperature is less than 10° C., the treatment takes a long time and is not practical. Semi-cured refers to the range generally referred to as the B stage in the curing process of thermosetting resins, and refers to a state in which the resin flows when heat is applied and a curing reaction can occur.

Next, a polyimide resin laminate can be made by laminating one or more of the polyimide resin prepregs described above. That is, it is made by laminating and molding a prepreg with a metal foil such as copper, nickel, or aluminum, or a metal foil with a circuit formed thereon, as necessary. The lamination molding can be performed by a conventional method.

[0025] In this laminate, a polyimide resin composition in which DAP is blended with a polyimide resin having the above chemical structure is used, and the base material is sufficiently filled with the resin composition. Therefore, by using this laminate, it is possible to obtain a laminate with a low dielectric constant and high through hole reliability, and a brominated resin having a reactive group is added to the polyimide resin composition containing this DAP. In a laminate using a blended polyimide resin composition, it is possible to obtain a laminate that has interlayer adhesion strength, through-hole reliability, and heat resistance and flame retardancy.
Multilayer laminates with more than one layer have useful properties.

The resin composition of the present invention is not limited to the above description, and may also be used as resins for covering electric wires, resins for semiconductor encapsulation, resins for heat-resistant molding materials, low dielectric constant and low moisture absorption. It is also useful as a resin for molding materials.

Next, the above invention will be explained by referring to examples and comparative examples.

[0028]

[Example] Examples 1 to 8 and Comparative Examples 1 and 2 were made of polyimide resin compositions having the respective formulations shown in the upper half of Table 1, and the characteristic values of laminates made of these resin compositions are shown below. It is shown in the lower half of 1.

The following polyimide resins in Table 1 were used. #1 is synthesized from maleic acid N,N-4.4-diphenylmethane-bis-imide and 4.4-diaminodiphenylmethane, and does not contain an alkyl group or an alkylene group in the resin molecule. #2 is
It is synthesized from 1,4-bis(2-p-anilinopropylidene)benzene-bis-imide and 1,4-bis(2-m-anilinopropylidene)benzene, and the alkyl group is added to the resin. Contains 17% by weight in the molecule.

The brominated resins used as flame retardants are those represented by (1) and (2) in Chemical Formula 1 at the end of the specification, respectively, and the types are specified with (■) in front of the compounding amounts in Table 1. ■ is a reactive brominated phenol.
Lunovolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., BREN
-S) ■ is a non-reactive polycyclic aromatic brominated resin (manufactured by Gray Lake Co., Ltd., BC58), and the accelerator is 2-ethyl-4-methylimidazole (2E4MZ, Shikoku Kasei Co., Ltd.). The diluting solvent has a resin solids content of about 55~
DMF was used in each case to give a concentration of 70%.

From the comparison of the dielectric constant characteristic values of Examples 1 to 3 and 5 to 7 and Comparative Example 1 in Table 1, the D
It was confirmed that the dielectric constant decreased as the amount of AP added increased. Furthermore, from a comparison of the chemical structures of #1 polyimide resin in Examples 1 to 3 and 5 to 7 and #2 polyimide resin in Examples 4 and 8, it was found that 11% by weight of alkyl groups were contained in the resin molecules.
In the case of #2 containing the above, it was confirmed that the effect of further lowering the dielectric constant was achieved. This dielectric constant measurement is based on JIS, C
6481.

[0032] Furthermore, in the formulations of reactive brominated resins having reactive groups in Examples 5 to 8, the interlayer adhesion strength and It was confirmed that flame retardancy could be ensured while maintaining a high level of heat resistance. This flame retardancy test was conducted according to UL-94.

Next, the resin composition shown in Table 1 was applied to a thickness of 0.1 m.
m, 95 g/m2 E glass cloth impregnated, 140
Each prepreg was obtained by drying for 35 to 60 minutes in a dryer at .degree. A laminate was formed using this prepreg in the following manner.

[0034] A double-sided roughened copper foil of 18 μm was placed on both sides of the prepreg, and a steam press was used to heat the molding temperature to 1.
30℃, molding pressure 30kg/cm2, molding time 90
Lamination molding was carried out under conditions of 1 minute to obtain a double-sided copper-clad laminate for an inner layer printed wiring board. The copper foil of the double-sided copper-clad laminate thus obtained was etched to form a circuit and blackened to create an inner layer printed wiring board, and 35 inner layer printed wiring boards were placed between each of the above-mentioned inner layer printed wiring boards. The same 4 sheets of prepreg as above are layered, and 35 μm thick copper foil is layered above and below through 4 sheets of prepreg, 6
Place it in a mold of 5 kg/cm using a steam press.
Immediately heat to 130 °C while applying pressure in step 2.
It was held for 0 minutes. Thereafter, it was heated to 200° C. under a pressure of 30 kg/cm 2 and held for 120 minutes, and then cooled to room temperature while the pressure was applied to obtain a double-sided copper-clad multilayer laminate.

The adhesion force when the layers of this laminate are peeled off in a 90 degree direction is expressed as the interlayer adhesion force [k] of the characteristic values in Table 1.
g/cm]. Also, 0.4 mm on this laminate
Using a φ drill bit, the rotation speed is 40,000 rpm, and the feed rate per rotation is 50 μ/rev.
00 holes were drilled and throughhole plating was performed using a combination of electroless plating and electrolytic plating using a conventional method, and the cross section of the throughholes at holes 990 to 1000 was observed with a microscope to determine the throughholes produced during throughhole plating. The plating penetration length and through-hole wall surface roughness were measured, respectively, and the results are shown in the characteristic value column of Table 1. Furthermore, in Examples 5 to 8 in which reactive flame retardants were added, the penetration length of throughhole plating was also lower than in Examples 5 to 8, in which DAP was added.
The wall surface roughness of the sample was also reduced compared to Comparative Examples 1 and 2. However, in Example 3, in which a non-reactive brominated resin is blended to impart flame retardancy, although flame retardance is obtained, heat resistance is reduced. Due to this decrease in heat resistance, the through-hole wall surface becomes rough and cracks occur due to the heat generated during drilling, resulting in poor plating penetration length and through-hole wall surface roughness, and the DAP formulation. The effect of using a large amount will be lost. However, when a reactive brominated resin is blended as described above, flame retardancy can be ensured and heat resistance is not reduced. This prevents the through-hole wall surface from becoming rough or cracking due to heat generated during drilling, and the through-hole plating penetration length and through-hole wall roughness are significantly reduced compared to comparative examples. .

The resin composition of the present invention is not limited to the above description, and may also be used as a resin for covering electric wires, a resin for semiconductor encapsulation, a resin for heat-resistant molding materials, a resin with a low dielectric constant or a low moisture absorption. It is also useful as a resin for molding materials.

[0037]

Effects of the Invention: A laminate obtained by obtaining a prepreg using the polyimide resin composition of the present invention, laminating and curing the prepreg reduces the dielectric constant of the laminate, and increases the propagation speed of electric signals. It is suitable for use in a single-layer multilayer laminate due to high through-hole reliability due to good filling properties of the resin into the base material, and furthermore, it is possible to improve safety due to flame retardancy.

[0038]

[Chemical formula 1]

[0039]

[Table 1]

Claims (12)

[Claims] 1. A polyimide comprising: 1) a polyimide resin, 2) diallyl phthalate blended in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the polyimide resin, and 3) a promoter, a solvent, etc. Resin composition. 2. The polyimide resin of claim 1 is a polyimide resin prepared by reacting an unsaturated bis-imide with a diamine, and wherein at least one of an alkyl group or an alkylene group other than a methylene group is added to the polyimide resin. The polyimide resin composition according to claim 1, wherein the polyimide resin composition contains at least % by weight. 3. The polyimide resin composition according to claim 1 is blended with a brominated resin having a reactive group in an amount of 1 to 50 parts by weight of bromine based on 100 parts by weight of the polyimide resin. The polyimide resin composition according to claim 1. 4. The polyimide resin composition according to claim 1, wherein the brominated resin having a reactive group according to claim 3 is a brominated epoxy resin. 5. 1) a polyimide resin; 2) diallyl phthalate blended in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the polyimide resin; 3) a polyimide comprising an accelerator, a solvent, etc. A polyimide resin prepreg characterized by impregnating a base material with a resin composition and semi-curing it. 6. The polyimide resin of claim 5 is a polyimide resin prepared by reacting an unsaturated bis-imide with diamide, and wherein at least one of an alkyl group or an alkylene group other than a methylene group is added to the polyimide resin. The polyimide resin prepreg according to claim 5, wherein the polyimide resin prepreg contains at least % by weight. 7. The polyimide resin composition according to claim 5 is blended with a brominated resin having a reactive group in an amount of 1 to 50 parts by weight of bromine based on 100 parts by weight of the polyimide resin. The polyimide resin prepreg according to claim 5. 8. The polyimide resin prepreg according to claim 5, wherein the brominated resin having a reactive group according to claim 7 is a brominated epoxy resin. 9. 1) a polyimide resin; 2) diallyl phthalate blended in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the polyimide resin; 3) a polyimide comprising an accelerator, a solvent, etc. A polyimide resin laminate, characterized in that one or more semi-cured prepregs are laminated and cured by impregnating a base material with a resin composition. 10. The polyimide resin of claim 9 is a polyimide resin prepared by reacting an unsaturated bis-imide with diamide, and wherein at least one of an alkyl group or an alkylene group other than a methylene group is added to the polyimide resin. The polyimide resin laminate according to claim 9, characterized in that the polyimide resin contains at least % by weight. 11. The polyimide resin composition according to claim 9 is blended with a brominated resin having a reactive group in an amount of 1 to 50 parts by weight of bromine based on 100 parts by weight of the polyimide resin. The polyimide resin laminate according to claim 9. 12. The polyimide resin laminate according to claim 9, wherein the brominated resin having a reactive group according to claim 11 is a brominated epoxy resin.