JP2001007240A - Printed wiring board for high heat radiating ball grid array type semiconductor plastic package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board for high heat radiating BGA type semiconductor plastic package having excellence in heat radiation, heat resistance, electrical insulation after moisture absorption, anti-migration property and the like. SOLUTION: A throughhole is drilled in a laminated plate having a glass fabric as a base material and a copper foil on both surfaces. After copper plating is performed, a circuit is formed. The glass fabric base material and a thermosetting resin composite on the rear side copper foil portion, which is used as a semiconductor chip mounting portion, is cut and removed by sandblasting. Then, a noble metal plating is performed to form a printed wiring board. Furthermore, a polyfunctional cyanate ester resin composite is used as a resin for the copper foiled laminated plate and a prepreg.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a compact printed wiring board having at least one semiconductor chip mounted thereon.
The present invention relates to a high heat dissipation type printed circuit board for a ball grid array type semiconductor plastic package. The obtained printed wiring board has a semiconductor chip mounted thereon and is used for applications such as microcontrollers, ASICs, and memories. This package is connected to a motherboard printed wiring board using solder balls, and is used as an electronic device or the like.

[0002]

2. Description of the Related Art Conventionally, as a base material of a semiconductor plastic package, a thin plate such as a glass epoxy material, a polyimide film material, and a ceramic material has been mainly used. These packages have a solder ball spacing of 0.8 mm
As described above, the solder ball pitch and the circuit line / space are becoming narrower in recent years in order to reduce the thickness, size, and weight, and the heat resistance of the substrate and the electrical insulation after absorbing moisture when a multilayer board is formed. , Migration resistance and the like have been problems. In recent years, in a printed wiring board having a higher density, heat generated from a semiconductor chip cannot be sufficiently released by a conventional semiconductor plastic package.

[0003]

SUMMARY OF THE INVENTION The present invention provides a high heat dissipation type ball grid array type printed wiring board for a semiconductor plastic package, which solves the above problems.

[0004]

SUMMARY OF THE INVENTION The present invention provides a high heat dissipation semiconductor plastic package as a substrate.
Using a glass cloth substrate double-sided copper-clad laminate, create a circuit board with semiconductor chip bonding terminals, solder ball connection pads, circuits and through holes, and then place the semiconductor chip on the opposite copper foil A glass cloth and a thermosetting resin are removed preferably by a sand blast method to expose a surface of a copper foil on a back surface for fixing a semiconductor chip to provide a substrate. Thereafter, at least the semiconductor chip mounting portion, the bonding terminal portion, and the solder ball pad portion are plated with nickel and gold to form a printed wiring board. Furthermore, as a resin used for the double-sided copper-clad laminate, a polyfunctional cyanate ester, by using a thermosetting resin composition containing the cyanate ester prepolymer as an essential component, heat resistance, after moisture absorption A high heat dissipation type ball grid array type printed wiring board for a semiconductor plastic package having excellent properties such as electrical insulation and migration resistance was obtained.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a printed wiring board for a semiconductor plastic package of a high heat dissipation type ball grid array type according to the present invention will be described. First, a through hole is opened in a glass cloth substrate double-sided copper-clad laminate, and a through-hole copper plating is applied. Next, after forming the circuit on the front and back, the glass cloth base material and the thermosetting resin composition on the upper side up to the copper foil on the back surface serving as the semiconductor chip mounting portion are removed preferably by a sandblast method. Thereafter, the sandblast residue is cleaned by soft etching or the like, and at least the semiconductor chip mounting portion, the bonding pad portion, and the ball pad portion are plated with nickel or gold to form a printed wiring board. The method of making a printed wiring board is not limited to the above method, for example, drilling a through-hole, applying copper plating to the through-hole, a glass cloth substrate and a thermosetting resin composition by a sand blast method up to the copper foil on the opposite surface. A generally known method such as cutting, forming a circuit using a liquid resist, removing the liquid resist, and then plating with a noble metal can be employed. After removing the glass cloth base material and the thermosetting resin plastic material, the semiconductor chip is bonded and fixed with a heat conductive adhesive on the copper foil on the back of the printed wiring board, connected to the bonding pad by wire bonding, and the surface is Seal with a sealing resin. On the back surface, solder balls are melt-bonded to form a semiconductor plastic package. In addition, by using a polyfunctional cyanate resin composition as the thermosetting resin composition of the double-sided copper-clad laminate, a print excellent in heat resistance, heat resistance after pressure cooker, migration resistance, etc. A wiring board is obtained.

As the double-sided copper-clad laminate of the present invention, a generally known glass cloth, preferably a woven cloth, is impregnated with a thermosetting resin and dried by placing electrolytic copper foil on both sides of a prepreg. What is obtained by laminating under heat, pressure and preferably under vacuum is used.

Examples of the glass fiber include nonwoven fabrics and woven fabrics using generally known glass fibers, for example, glass fibers such as E, S, and D, and generally have a thickness of 50 to 150 μm. Also, a blending using these yarns can be used. In the base material, a thin material is preferably a material having a high density. For example, 50
For a thickness of μm, 50 to 60 g / m ² is preferred. The weaving method is not particularly limited, but plain weaving is preferable. Nonwoven fabrics and woven fabrics made of organic fibers can be used, but a rigid glass cloth base material is preferable from the viewpoint of dust and the like.

As the resin of the thermosetting resin composition used in the present invention, generally known thermosetting resins are used. Specifically, an epoxy resin, a polyfunctional cyanate ester resin, a polyfunctional maleimide-cyanate ester resin, a polyfunctional maleimide resin, an unsaturated group-containing polyphenylene ether resin, and the like, and one or more kinds Are used in combination. From the viewpoints of heat resistance, migration resistance, electrical properties after moisture absorption, and the like, a polyfunctional cyanate ester resin composition is preferred.

The polyfunctional cyanate compound which is a preferred thermosetting resin component of the present invention is a compound having two or more cyanato groups in the molecule. Specific examples include 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1,6-, 1,8-, 2 , 6- or 2,
7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4-dicyanatobiphenyl, bis (4-dicyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) propane, 2, 2-bis (3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-cyanatophenyl) sulfone, tris (4 -Cyanatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting novolak with cyanogen halide.

In addition to these, Japanese Patent Publication Nos. 41-1928 and 43-1846
8, polyfunctional cyanate compounds described in JP-A-44-4791, JP-A-45-11712, JP-A-46-41112, JP-A-47-26853 and JP-A-51-63149 can also be used. Further, a prepolymer having a molecular weight of 400 to 6,000 and having a triazine ring formed by trimerization of a cyanato group of these polyfunctional cyanate compounds is used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer with a catalyst such as an acid such as a mineral acid or a Lewis acid; a base such as a tertiary amine such as sodium alcoholate; or a salt such as sodium carbonate. It can be obtained by: The prepolymer also contains some unreacted monomers and is in the form of a mixture of the monomer and the prepolymer, and such a raw material is suitably used for the purpose of the present invention. Generally, it is used after being dissolved in a soluble organic solvent.

As the epoxy resin, a generally known epoxy resin can be used. Specifically, liquid or solid bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, alicyclic epoxy resin; butadiene, pentadiene, vinylcyclohexene, dicyclopentyl ether, etc. And polyglycidyl compounds obtained by reacting a polyol, a hydroxyl-containing silicone resin with an epohalohydrin, and the like. These may be used alone or in combination of two or more.

As the polyimide resin, generally known ones can be used. Specific examples include a reaction product of a polyfunctional maleimide and a polyamine, and a polyimide having a terminal triple bond described in JP-B-57-005406.

These thermosetting resins may be used alone, but it is preferable to use them in an appropriate combination in consideration of the balance of properties.

Various additives can be added to the thermosetting resin composition of the present invention, if desired, as long as the inherent properties of the composition are not impaired. These additives include polymerizable double bond-containing monomers such as unsaturated polyesters and prepolymers thereof; polybutadiene, epoxidized butadiene, maleated butadiene, butadiene-
Low molecular weight liquid to high molecular weight elastic rubbers such as acrylonitrile copolymer, polychloroprene, butadiene-styrene copolymer, polyisoprene, butyl rubber, fluororubber, natural rubber; polyethylene, polypropylene, polybutene, poly-4-methyl Penten, polystyrene, AS
Resin, ABS resin, MBS resin, styrene-isoprene rubber,
Polyethylene-propylene copolymer, 4-fluoroethylene-
6-fluorinated ethylene copolymers; high molecular weight prepolymers or oligomers such as polycarbonate, polyphenylene ether, polysulfone, polyester, and polyphenylene sulfide; and polyurethane are exemplified and used as appropriate. In addition, other known inorganic and organic fillers,
Various additives such as dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents, photosensitizers, flame retardants, brighteners, polymerization inhibitors, and thixotropic agents may be used as desired. They are used in an appropriate combination. If necessary, the compound having a reactive group is appropriately blended with a curing agent and a catalyst. In order to increase the rigidity of the resin composition, it is preferable to add 20 to 80% by weight of an inorganic filler.

The thermosetting resin composition of the present invention can be cured by heating itself, but has a low curing rate and is inferior in workability and economic efficiency. Can be used. The amount used is 0.005 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the thermosetting resin.

The glass cloth substrate-reinforced copper-clad laminate is first impregnated with a thermosetting resin composition and dried to obtain
A prepreg is prepared by heating and drying at 0 to 180 ° C., preferably 120 to 150 ° C. to form a B stage. Next, double-sided copper-clad laminate, copper foil on both sides of this prepreg, heating, pressing,
Preferably, it is laminated and formed under vacuum to obtain a copper-clad laminate. The thickness of the copper foil is preferably 18-70 μm.

As the sandblasting method, generally known ones can be mentioned. Specifically, a dry or wet sand blast method can be used. The type of sand is not particularly limited, but generally known ones such as silica sand and glass powder can be used. It is sprayed to the place where sand is to be ground, and the glass cloth base material and the thermosetting resin composition are ground and removed. Cover the parts that are not to be cut in advance or apply resin, and protect the parts other than to be cut off when sand is sprayed. The method of shaving the resin and glass cloth layer is not limited to the sandblast method,
A generally known router, laser, or the like can be used.

Thereafter, the surface of the copper foil is preferably cleaned by performing a process such as soft etching, and nickel plating and gold plating are performed by a standard method. In this case, it is also possible to perform precious metal plating first and then cover with a permanent protection resist.

[0019]

The present invention will be specifically described below with reference to examples and comparative examples. Unless otherwise specified, “parts” indicates parts by weight. Example 1 900 parts of 2,2-bis (4-cyanatophenyl) propane,
100 parts of (maleimidophenyl) methane are melted at 150 ° C,
The mixture was reacted for 4 hours with stirring to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. Add bisphenol A type epoxy resin (trade name: Epicoat 1001, Yuka Shell Epoxy Co., Ltd.)
) And 600 parts of a cresol novolac type epoxy resin (trade name: ESCN-220F, manufactured by Sumitomo Chemical Co., Ltd.) were uniformly mixed and dissolved. Further, as a catalyst, zinc octylate 0.4
Was added and dissolved and mixed. To this, 500 parts of an inorganic filler (trade name: calcined talc, manufactured by Nippon Talc Co., Ltd.) and 8 parts of a black pigment were added, followed by uniform stirring and mixing to obtain Varnish A. This varnish is impregnated with a glass woven fabric of 100 μm thickness and dried at 150 ° C.,
Gelation time (at 170 ° C) 120 seconds, resin composition content is 51 wt%
Prepreg B was prepared.

An electrolytic copper foil having a thickness of 18 μm was placed on both sides of the two prepregs B and laminated and molded at 200 ° C., 20 kgf / cm ² , and a vacuum of 30 mmHg or less for 2 hours. ,
a) was obtained. In places other than fixing this semiconductor chip,
A through-hole with a diameter of 0.2 mm for connecting the front and back circuits was opened, and 20 μm of through-hole plating was applied (FIG. 1, b). Circuit on front and back
(FIG. 1, c) is formed, and a portion other than the upper portion of the backside copper foil to be a semiconductor chip mounting portion is covered with a sandblasting resist, and sandblasting sand is sprayed from the surface, a glass cloth base material, thermosetting. The resin composition was cut to expose the surface of the inner bonding pad portion. Thereafter, the sandblasting resist was peeled off and removed with an alkaline aqueous solution, and after soft etching, a portion other than the semiconductor chip mounting portion, the bonding pad portion and the ball pad portion was covered with a plating resist, and nickel plating and gold plating were performed to produce a printed wiring board. . The semiconductor chip mounting portion of this printed wiring board (FIG. 1,
d) A 4mm square semiconductor chip (Fig. 1, e) is bonded and fixed with a silver paste (Fig. 1, f), and wire bonded (Fig. 1, g).
Thereafter, sealing was performed with a liquid epoxy sealing resin (FIG. 1, h). Table 1 shows the evaluation results of the semiconductor plastic package.

Comparative Example 1 In Example 1, 700 parts of an epoxy resin (trade name: Epicoat 5045), 300 parts of an epoxy resin (trade name: ESCN-220F), and dicyandiamide 35 were used as the thermosetting resin composition.
And 1 part of 2-ethyl-4-methylimidazole was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and the mixture was uniformly stirred and mixed. This was impregnated into the same glass cloth as in Example 1, dried, and gelled for 15 minutes.
Prep C for 0 seconds was created.

Using two prepregs C (FIG. 2, l),
Place 18μm electrolytic copper foil (Figure 2, k) on both sides, 190 ℃, 20k
Laminate molding was performed under vacuum of gf / cm ² and 30 mmHg or less to prepare a double-sided copper-clad laminate. Circuits are formed on both sides, copper-plated through holes (FIG. 2, m) for heat dissipation are formed in the copper foil portion of the semiconductor chip mounting portion, and the semiconductor chip mounting portion, wire bonding pad portion, and solder ball pad are formed. The other parts are covered with plating resist (Fig. 2, i), nickel plating, gold plating to make a printed wiring board, the surface is mounted with a semiconductor chip (Fig. 2, e), wire bonding (Fig. 2,
g), epoxy resin compound sealing (Fig. 2, h),
The back surface was joined with a solder ball (FIG. 2, j) to form a semiconductor plastic package. Table 1 shows the evaluation results.

[0023]

[Table 1]

<Measurement method> 1) Glass transition temperature Measured by the DMA method. 2) Insulation resistance value after pressure cooker processing Create a comb pattern with line / space = 50 / 50μm,
On this, the prepregs respectively used were arranged, and the laminated and molded one was treated at 121 ° C. and 2 atm for a predetermined time,
Post-treatment was performed at 25 ° C. and 60% RH for 2 hours, and the insulation resistance value between the terminals was measured 60 seconds after 500 VDC was applied. 3) Migration resistance The test piece of 3) was applied at 85 ° C. and 85% RH at 50 VDC to measure the insulation resistance between terminals. 4) Heat dissipation The package was bonded to the same motherboard printed wiring board with solder balls and used continuously for 1000 hours before measuring the package temperature.

[0025]

According to the present invention, a through hole is formed in a glass-clad double-sided copper-clad laminate, copper plating is performed, and a circuit is formed on the front and back surfaces. The cloth substrate and the thermosetting resin composition were cut and removed by sandblasting, and at least the semiconductor chip mounting portion, the bonding pad portion, and the ball pad portion were subjected to noble metal plating, and the semiconductor chip was formed into a printed wiring board. A semiconductor plastic package excellent in heat dissipation is provided by bonding and fixing with a heat conductive adhesive, mounting a semiconductor chip by wire bonding, and sealing with a sealing resin. Furthermore, by using a polyfunctional cyanate ester as the thermosetting resin composition and the cyanate ester prepolymer as an essential component, it is excellent in heat resistance, electric insulation after pressure cooker treatment, migration resistance and the like. Was obtained, and a product suitable for mass production was obtained.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of a printed wiring board of Example 1 and a semiconductor plastic package using the same.

FIG. 2 is a manufacturing process diagram of a semiconductor plastic package of Comparative Example 1.

[Explanation of symbols]

 a Glass cloth substrate double-sided copper-clad laminate b Copper-plated through hole c Circuit d Copper foil with semiconductor chip e Semiconductor chip f Heat conductive adhesive g Bonding wire h Sealing resin i Plating resist j Solder ball k Copper foil l Prepreg C m Heat dissipation through hole

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Katsuji Komatsu 6-1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo factory F-term (reference) 5E336 AA04 AA08 BB02 BB16 BB17 BC15 BC26 BC34 CC31 CC43 CC58 EE08 GG03 5E338 AA02 AA16 AA18 BB03 BB05 BB19 BB25 CC01 CC04 CD02 EE02

Claims (3)

[Claims] 1. A glass cloth substrate on both sides of a copper-clad laminate,
After creating a circuit board on which circuits, semiconductor chip bonding terminals, solder ball connection pads, and through-hole conductors are arranged, remove the glass cloth base material and thermosetting resin on the upper side of the place where the semiconductor chip is to be mounted, and remove the opposite side. A printed circuit board for a high heat dissipation ball grid array type semiconductor plastic package, wherein a surface of a copper foil for fixing a semiconductor chip formed on the copper foil is exposed. 2. The printed wiring board according to claim 1, wherein the glass cloth substrate and the thermosetting resin composition are removed by a sandblast method. 3. The thermosetting resin composition of a glass cloth substrate double-sided copper-clad board is a thermosetting resin composition containing a polyfunctional cyanate ester and the cyanate ester prepolymer as essential components. 3. The printed wiring board for a high heat dissipation ball grid array type semiconductor plastic package according to 1 or 2.