JPH0582928A - Manufacture of multilayered printed circuit board - Google Patents

Abstract

PURPOSE:To obtain a multilayered printed circuit board which enables high- density wiring, has flame retardancy and body permittivity, and is small in signal delay time by a method wherein an essential component of prepreg resin is a prepolymer of poly(p-hydroxystyrene) derivative. CONSTITUTION:In a multilayered printed circuit board where prepregs impregnated with resin into fiber cloths and circuit boards having circuit conductor layers are alternately piled up and adhered, an essential component of resin should be a prepolymer of poly(p-hydroxystyrene) derivative expressed by Formula [A is any of hydrogen, alkyl group, and halogen group; R is alkenoyl group of carbon number 2-4, aryl group, butanyl group, vinyl group, acryloyl group, methacryloyl group, or epoxymethacryloyl group; m is 1-4; and n is 1-100]. This structure can provide a compact multilayered printed substrate and reduce delay time of signal transmission by about 15%.

Description

Detailed Description of the Invention

[0001]

The present invention has a low dielectric constant characteristic,
In consideration of heat resistance, dimensional stability and flame retardancy, a novel multilayer printed circuit board having a small signal delay time is provided.

[0002]

2. Description of the Related Art Conventionally, a multilayer printed circuit board for industrial use such as a computer is a phenol resin containing a brominated modified resin or an addition type flame retardant for imparting flame retardancy.
Laminates using insulating materials such as epoxy resin and polyimide resin are mainly used. In particular, high density is desired for a large computer, and a polyimide resin having excellent heat resistance and dimensional stability is used as an insulating material. However, in recent years, with the increase in high-speed arithmetic processing of large-scale computers, a printed circuit board having excellent electrical characteristics has been demanded in order to improve the signal transmission speed. In particular, a printed circuit board having a low dielectric constant is required in order to shorten the signal transmission delay time and reduce the circuit thickness. As such a low dielectric constant laminated material, a laminated board using tetrafluoroethylene resin (PTFE) or polybutadiene resin has been developed. Examples of the laminated plate of this type include, for example, Proceeding N.P.C.O.N., (1981), pages 160 to 169 (Proc. NEPCON (1981) P.P160).
169) and JP-A-55-127426.

[0003]

However, since the resin is thermoplastic and the glass transition temperature is low, the PTFE laminated plate has a problem that the coefficient of thermal expansion is large at a high temperature and the dimensional stability is not sufficient. There is a concern about the reliability of through holes when they are chemically bonded, and when applied to a multilayer printed circuit board, the wiring density is about the same as that of epoxy resin, and there is not much merit as a low dielectric constant material. Further, since PTFE does not have a suitable solvent, a bonding method by heating, melting and pressing is generally used, but it has a drawback that the melting temperature is very high. Polybutadiene resin has a drawback that it is flammable due to its molecular structure. To impart flame retardancy, addition type flame retardants such as decabromodiphenyl ether and triphenyl phosphate, tribromophenyl methacrylate and tribromophenyl acrylate are added. Although it is necessary to add a reactive flame retardant such as, there is a problem in that the addition of these impairs the electrical characteristics, heat resistance, and dimensional stability inherent in the polybutadiene resin.

An object of the present invention is to provide a method for manufacturing a multilayer printed circuit board which enables high-density wiring, has flame retardancy, has a low dielectric constant, and has a short signal delay time.

[0005]

The present invention provides a method for producing a multilayer printed circuit board in which a prepreg in which a fiber cloth is impregnated with a resin and a circuit board having a circuit conductor layer are alternately laminated and adhered. Formula (I)

[0006]

[Chemical 2]

(In the formula, A is hydrogen, an alkyl group or a halogen group, and R is an alkenoyl, allyl, butanyl, vinyl, acryloyl, methacryloyl or epoxymethacryloyl group having 2 to 4 carbon atoms. And m is a number of 1 to 4 and n is a number of 1 to 100). A multilayer printed circuit board comprising a prepolymer of a poly (p-hydroxystyrene) derivative as an essential component. And a resin of the insulating layer of the circuit board, which is a composition containing a prepolymer of the poly (p-hydroxystyrene) derivative represented by the general formula (I) as an essential component. The present invention relates to a method for manufacturing a multilayer printed circuit board.

The present invention provides a resin for an insulating layer of a multilayer printed circuit board, represented by the following general formula (I):

[0009]

[Chemical 3]

(In the formula, A is hydrogen, an alkyl group and a halogen group, and R is an alkenyl or alkenoyl group having 2 to 4 carbon atoms, or an allyl group, butenyl group, vinyl group, acryloyl group, methacryloyl group, epoxy methacryloyl group. Where m is 1 to 4 and n is a number from 1 to 100), and a composition containing a prepolymer composed of a poly (p-hydroxystyrene) derivative as an essential component is preferable.

For example, a resin composition prepared by mixing at least one compound selected from polybutadiene and polyvalent carboxylic acid allyl ester with a prepolymer composed of the poly (p-hydroxystyrene) derivative represented by the above formula (I). Is preferably used.

The above polybutadiene and allyl carboxylic acid allyl ester are preferably 50% by weight or less of the total amount of the resin, particularly 30% by weight or less for the former and 20% by weight or less for the latter.

As the conductor layer of the present invention, a metal foil of copper, silver, gold, aluminum, chromium, molybdenum, tungsten or the like, or a circuit formed by plating, vapor deposition or the like is used. Particularly, copper is preferable, and copper foil is preferable.

As the insulating layer of the present invention, a vinyl ether, isobutenyl ether, allyl ether, acrylic acid ester, methacrylic acid ester of poly (p-hydroxystyrene) as the compound represented by the general formula (I) as described above. , Epoxy methacrylate and its bromide. These may be used alone or in combination of two or more as desired.

Examples of polybutadiene include 1,2-polybutadiene, cyclized polybutadiene, terminal epoxidized polybutadiene, polybutadiene glycol, polybutadiene carboxylic acid, urethane modified polybutadiene, maleated polybutadiene, terminal acrylic modified polybutadiene, and terminal ester modified polybutadiene. Various polymers and non-polymers containing polybutadiene having a vinyl side chain as a basic component can be used.

The polycarboxylic acid allyl ester is, for example, triallyl trimellitate, diallyl terephthalate,
Diallyl isophthalate, diallyl orthophthalate,
Triallyl trimellitate, triallyl cyanurate,
Triallyl isocyanurate, trimetaallyl isocyanurate, p, p'-dialyloxycarbonyldiphenyl ether, m, p'-dialyloxycarbonyldiphenyl ether, o, p'-dialyloxycarbonyldiphenyl ether, m, m'-di It is also possible to use one kind or a mixture of two or more kinds such as allyloxycarbonyl diphenyl ether. Further, a prepolymer obtained by preliminarily reacting these is also useful. By adding polybutadiene and polyvalent carboxylic acid allyl ester to the poly (p-hydroxysterene) derivative represented by the above general formula (I), flexibility, adhesiveness with copper foil, mechanical properties and the like are improved. The blending amount of these is not particularly limited, but if the blending amount increases, flame retardancy, heat resistance, dimensional stability, etc. decrease.

An example of a method for manufacturing a multilayer printed circuit board according to the present invention will be described.

First, a varnish is prepared by dissolving a poly (p-hydroxystyrene) derivative, polybutadiene, and a polycarboxylic acid allyl ester in an organic solvent. Examples of the organic solvent include toluene, xylene, acetone,
Methyl ethyl ketone, methyl isobutyl ketone, N, N
-Dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, trichloroethylene, trichloroethane, methylene chloride, dioxane, carbon tetrachloride, tetrachloroethylene, cyclohexanone, ethyl acetate, etc., which is a solvent that uniformly dissolves the resin composition. Can be used. A hardener such as a radical polymerization initiator is added to the varnish thus prepared to prepare an impregnating varnish.

Examples of radical polymerization initiators are benzoyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, t-butyl peroxylavate, di-t-butyl peroxyphthalate, dibenzyl oxide and 2,5- Dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, t-butylhydroperoxide, di-t-butylperoxide 2,5-dimethyl-2,5-di (t -Butylperoxy) hexane (3), diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, pinane hydroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, cumene hydroperoxide, etc. .. These are resin compositions 10
0.1 to 10 parts by weight is preferably added to 0 parts by weight.

Next, the obtained impregnating varnish is impregnated onto a sheet-shaped substrate and dried at room temperature to 170 ° C. to obtain a prepreg having no tackiness. The setting of the drying temperature at this time depends on the solvent and the initiator used. After forming a circuit pattern on a cured laminated plate made of the obtained prepreg and copper foil, etc., stacking a required number of these, and sandwiching a prepreg sheet between them, 1 to 10 at 100 to 250 ° C.
Adhesive molding is performed under the condition of 0 kgf / cm ² to obtain a multilayer printed circuit board.

As the fiber cloth for the sheet-like base material, almost all fiber cloths generally used for laminated materials can be used. As the inorganic fiber, E glass, C glass, A glass, S glass, D containing SiO ₂ , Al ₂ O _3, etc. as components
Q using glass, YM-31-A glass and quartz
Various glass fibers such as glass can be used. Further, as the organic fiber, aramid fiber containing a polymer compound having an aromatic polyamideimide skeleton as a component can be used. The fiber cloth is preferably 20 to 40% by volume with respect to the insulating layer.

The present invention is a method for producing a multilayer printed circuit board, in which a prepreg in which a fiber cloth is impregnated with a resin and a circuit board having a circuit conductor layer are alternately laminated and adhered, and the resin is represented by the following general formula (I).

[0023]

[Chemical 4]

(Wherein A is any of hydrogen, an alkyl group and a halogen group, and R is an alkenoyl, an allyl group, a butanyl group, a vinyl group, an acryloyl group, a methacryloyl group or an epoxymethacryloyl group having 2 to 4 carbon atoms. A multilayer printed circuit, which is a composition containing as an essential component a prepolymer of a poly (p-hydroxystyrene) derivative represented by the formula (1) to (4) and m is a number from 1 to 4 and n is a number from 1 to 100. A method of manufacturing a board, wherein the resin of the insulating layer of the circuit board is a composition containing a prepolymer of a poly (p-hydroxystyrene) derivative represented by the general formula (I) as an essential component. The present invention relates to a method for manufacturing a multilayer printed circuit board.

The insulating layer has a thickness of 250 μm or less, preferably 2 to 5 fiber cloth layers per layer, and particularly 2 fiber cloth layers per thin layer having a thickness of 100 μm.
And the number of fiber cloth layers per one of the thick layers is 3 or less.
A layer having a thickness of 150 μm or less is preferable.

According to the present invention, pins provided on a ceramic multilayer circuit board on which semiconductor elements having a plurality of values are mounted are inserted and fixed in through holes provided on the multilayer printed board, and terminals of the multilayer printed board are provided on a backboard. In the method for producing an electrically connected multicore connector, at least one of the multilayer printed circuit board and the backboard is formed by alternately laminating a resin cloth-impregnated insulating layer and a circuit conductor layer. , The resin is of the general formula
A method for producing a structure including a multilayer printed circuit board, characterized by comprising a prepolymer of a poly (p-hydroxystyrene) derivative represented by (I) as an essential component, and a method for producing an insulating layer of the above-mentioned circuit board. The present invention relates to a method for producing a structure including a multilayer printed circuit board, wherein the resin is a composition containing a prepolymer of a poly (p-hydroxystyrene) derivative represented by the general formula (I) as an essential component.

[0027]

Example 1 250 g of brominated poly (p-hydroxystyrene) was dissolved in 500 g of chloroform, and sodium hydroxide 120 was added.
500g of aqueous solution was added with stirring, and the mixture was stirred at 25 ° C for 1
After reacting for a time, a sodium salt is obtained. Next, 200 g of a chloroform solution of 120 g of methacrylic acid chloride was gradually added and reacted at 25 ° C. for 2 hours, then the chloroform solution and the aqueous solution were separated, the chloroform solution and the aqueous solution were separated, and the chloroform solution was concentrated to give a reaction product. To get Further, this reaction product was dissolved in acetone, and the solution was added dropwise to methanol for purification.

The brominated poly (p-hydroxystyrene) methacrylate obtained as described above is dissolved in methyl ethyl ketone to obtain a varnish having a solid content of 40 to 50% by weight. Further, 3 parts by weight of dicumyl peroxide was added as a radical polymerization initiator to 100 parts by weight of the resin, and the varnish was then treated with E-glass cloth (thickness: 50 m).
Was impregnated and dried at 60 to 80 ° C. for 10 to 20 minutes to obtain a tack-free prepreg. Next, two prepregs were stacked and the prepreg side was surface-roughened copper foil (35 μm
Thickness) on both sides, pressure 30kgf / cm ² , temperature 180
It was heated at 0 ° C for 30 minutes and further pressed at 170 ° C for 1 hour to obtain a copper-clad laminate. The thickness of this insulating layer is about 10
It is 0 μm. An inner layer circuit pattern such as a signal layer, a power supply layer and a matching layer was formed on the obtained copper clad laminate by photoetching, and the copper surface of the circuit pattern was processed by the following method to form a double-sided wiring unit circuit sheet. ..

[0029]

[Outer 1]

Solution composition: (1) Concentrated hydrochloric acid 300 g, cupric chloride 50 g, distilled water 650
g (roughening of the copper surface).

(2) Sodium hydroxide 5 g, trisodium phosphate 10 g, sodium chlorite 30 g, distilled water 95
5 g (stabilization of copper surface).

After the above processing is completed, 30 layers are formed as the circuit conductor layer 2 by using the above prepreg resin sheet with the constitution shown in FIG. 1, 170 ° C., pressure 20 kg / c.
Adhesion was performed under conditions of m ² and 80 minutes to prepare a multilayer printed circuit board. Three prepreg resin sheets for multilayer adhesion were stacked. Its thickness is about 150 μm.

The multi-layered adhesion was performed by inserting guide pins into the holes provided on all four sides of the sheet to prevent misalignment.
After the multi-layered bonding, a hole having a hole diameter of 0.3 mm or 0.6 mm was opened by a microdrill, and the entire surface was subjected to chemical copper plating to form a through hole liquid 4. Next, the outermost layer circuit was formed by etching to form a multilayer printed circuit board. In the present embodiment, the thickness is about 4 mm × 570 mm × 420 mm, two kinds of line widths 70 μm and 100 μm, (channel / grid) 2-3 lines / 1.3 mm, and gap between layers is about 100 μm or less. I was able to get The glass cloth was about 30% by volume of the insulating layer.

Reference numerals 1 and 3 are insulating layers, 2 is a circuit conductor layer, 4 is a through hole, 1 is the above-mentioned expanded laminate, and 3 is a prepreg resin sheet.

Example 2 Multilayer printing was carried out in the same manner as in Example 1 except that brominated poly (p-hydroxystyrene) methacrylate obtained by reacting acrylic acid chloride in the same manner as in Example 1 was used. The circuit was manufactured.

Example 3 A multilayer printed circuit board was prepared in the same manner as in Example 1 except that brominated poly (p-hydroxystyrene) allyl ether obtained by reacting allyl chloride in the same manner as in Example 1 was used. Created.

Example 4 50 parts by weight of brominated poly (p-hydroxystyrene) methacrylate, 50 parts by weight of polybutadiene modified with diglycidyl ether bisphenol A, 3 parts by weight of dicumyl peroxide, 2-undecyl imidazole 2
A multilayer printed circuit board was prepared in the same manner as in Example 1 except that parts by weight were used.

Example 5 50 parts by weight of brominated poly (p-hydroxystyrene) acrylate, 45 parts by weight of phenol novolac type epoxy-modified polybutadiene, 5 parts by weight of triallyl isocyanurate, 3 parts by weight of dicumyl peroxide, 2- A multilayer printed circuit board was prepared in the same manner as in Example 1 except that 2 parts by weight of undecyl imidazole was used.

Comparative Examples 1 and 2 A prepreg resin sheet and a copper clad laminate were formed in the same manner as in Example 1 using epoxy resin and polyimide resin,
Similarly, a multilayer printed circuit board was manufactured. Comparative Example 1 with the former
And the latter was Comparative Example 2.

Comparative Example 3 50 parts by weight of 1,2-polybutadiene prepolymer 50 parts by weight of phenol novolac type epoxy-modified polybutadiene are dissolved in xylene to obtain a varnish having a solid content of 20 to 30% by weight. Furthermore, 3 parts by weight of dicumyl peroxide and 1 part by weight of 2-undecylimidazole were added as a radical polymerization initiator, and a multilayer printed circuit board was obtained in the same manner as in Example 1.

The characteristics of the brominated poly (p-hydroxystyrene) of the above Examples are shown in Table 1, and the main characteristics of the multilayer printed circuit boards according to these Examples and Comparative Examples are shown in Table 2.

As shown in Table 1, the bromine content is as high as 40% or more, and the thermal decomposition temperature is as high as 300 ° C. or more.
In particular, it can be seen that it has excellent properties when the relative dielectric constant is 3.5 or less.

[0043]

[Table 1]

[0044]

[Table 2]

The glass transition temperature was 10 mm in diameter and 2 mm in thickness, and the coefficient of thermal expansion of the cured resin was measured at a temperature rising rate of 2 ° C./min.
The temperature at which the coefficient of thermal expansion changes was defined as the glass transition temperature. The thermal decomposition temperature was measured at a temperature rising rate of 5 ° C / min in an air atmosphere for 10 mg of a sample obtained by crushing a resin cured product, and the temperature when the amount was reduced by 5% was defined as the thermal decomposition temperature. Relative permittivity is measured by glass cloth impregnated with resin and cured. JIS C64
The measurement was carried out according to 81 and the capacitance at a frequency of 1 MHz was measured and determined. The linear expansion coefficient is measured from 50 ° C to 20 ° C by measuring the coefficient of thermal expansion in the thickness direction of the laminated plate (10 mm square) at a temperature rising rate of 2 ° C / min.
It was obtained from the amount of change up to 0 ° C., and the value is almost the same as that of the resin. Solder heat resistance and bending properties were measured in accordance with JIS C6481, and solder heat resistance was examined at 260 ° C for 300 seconds to determine whether there was an abnormality in the appearance. The bending strength was measured at room temperature and 180 ° C. under the conditions that the glass cloth resin-impregnated laminated plate was cut into 25 × 50 mm, the distance between fulcrums was 30 mm, and the bending speed was 1 mm / min. The flame retardancy was measured according to the UL-94 vertical method, and was measured using a glass cloth resin-impregnated laminated board.

As shown in Table 2, each of the resin compositions used in the multilayer printed circuit board of the present invention contains a large amount of bromine, which is effective for flame retardancy, and is 180 ° C. or less, particularly in this example. It is cured by heating at a low temperature of 170 ° C or lower. Moreover, it is a suitable resin which has a small relative permittivity of 3.5 or less and a small linear expansion coefficient of 10 × 10 ⁻⁵ / ° C. or less, particularly 6 × 10 ⁻⁵ / ° C. or less.

Further, all glass transition temperatures are 200 ° C.
Above, especially those of 220 ° C. can be obtained. Moreover, the thermal decomposition temperature is 300 ° C. or higher, no blistering occurs even in solder heat resistance at 300 ° C., neither is abnormal, and flame retardancy is VO and bending strength is 40 at room temperature.
It is more than kg / mm. By using one having the above characteristics, the line width of the circuit conductor layer can be 100 μm or less, and even 70 μm is possible, and the number of channels / grid is 2-3 lines / 1.
It can be 3 mm. The thickness of the insulating layer may be 100 μm or less for the circuit conductor layer, and the prepreg multilayer adhesive layer may be 150 μm or less.

The multilayer printed circuit board obtained by the manufacturing method according to the present invention has a low dielectric constant characteristic like the polybutadiene-based material generally known as a low dielectric constant material, and is currently a multilayer printed circuit board for a large computer. Since the relative permittivity can be reduced from 4.7 to 3.5 or less as compared with the epoxy-based material and the polyimide-based material applied to, the signal transmission delay time can be 6.2 ns / m, which is a 15% reduction. Furthermore, the heat resistance and linear expansion coefficient characteristics shown by the glass transition temperature, thermal decomposition temperature, solder heat resistance, etc. are superior to those of epoxy-based materials and polybutadiene-based materials, and are equivalent to those of polyimide-based materials. .. The flame retardance complies with UL standard V-O class without the addition of flame retardants.

Embodiment 6 FIG. 2 is a perspective view showing an example of a computer mounting structure using a multilayer printed circuit board obtained by the manufacturing method of the present invention.

In the LSI multi-chip module package 55, an LSI is mounted on a water-cooled multilayer ceramic substrate, and the LSI is joined to the multilayer printed board 5 by pins provided on the substrate. Terminals for connection are provided at either end of the multilayer printed circuit board 5, and the connector 10
Is connected to both ends and connected to an external terminal. One of the connectors is connected to a multi-core connector provided on the backboard 6 to form a three-dimensional mounting structure. The LSI is cooled by water through the cooling pipe 9.

The multi-layer printed circuit board of the present invention is used for the backboard 6 and the multi-layer printed circuit board 5, and is manufactured in the same manner as in the first embodiment. In the computer-implemented structure using the multilayer printed circuit board of the present invention, as compared with the case where the signal transmission delay time is relative permittivity of 4.7, it is 15
% Can be reduced.

[0052]

The multilayer printed circuit board obtained by the manufacturing method of the present invention is compact because the insulating layer uses a resin having a low relative dielectric constant, heat resistance and flame retardancy, and a low thermal expansion coefficient. A multilayer printed circuit board can be provided. As a result, a remarkable effect that the signal transmission delay time can be reduced by about 15% as compared with the conventional case is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional perspective view of a multilayer printed circuit board showing an example of the present invention.

FIG. 2 is a perspective view showing a computer-mounted structure showing an example using the multilayer printed circuit board of the present invention.

[Explanation of symbols]

1 ... Resin impregnated cured sheet, 2 ... Circuit, 3 ... Prepreg resin sheet, 4 ... Through hole, 5 ... Multilayer printed circuit board,
6 ... back boat, 7 ... multi-core connector, 8 ... multi-chip module package, 9 ... cooling water pipe, 10 ... connector.

Front Page Continuation (72) Inventor Akio Takahashi 4026 Kuji Town, Hitachi City, Hitachi, Ibaraki Prefecture Hitachi Research Laboratory Ltd. (72) Inventor Motoyo Wajima 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitachi Research Co., Ltd. (72) Inventor Toshikazu Narahara 4026 Kujimachi, Hitachi City, Ibaraki Hitachi, Ltd., Hitachi Research Laboratory (72) Inventor Ryo Hiraga, 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd.

Claims (2)

[Claims] 1. A method for manufacturing a multilayer printed circuit board, wherein a prepreg impregnated with a resin on a fiber cloth and a circuit board having a circuit conductor layer are alternately laminated and adhered, wherein the resin is represented by the following general formula (I): (In the formula, A is any one of hydrogen, an alkyl group and a halogen group, R is an alkenoyl, an allyl group, a butanyl group, a vinyl group, an acryloyl group, a methacryloyl group or an epoxymethacryloyl group having 2 to 4 carbon atoms, A method for producing a multilayer printed circuit board, comprising a prepolymer of a poly (p-hydroxystyrene) derivative represented by the formula: m is 1 to 4 and n is a number from 1 to 100 .. 2. The resin for the insulating layer of the circuit board is a composition containing a prepolymer of a poly (p-hydroxystyrene) derivative represented by the general formula (I) as an essential component. 1. A method for manufacturing a multilayer printed circuit board according to 1.