JP2000236041A - Printed wiring board for chip-scale package superior in solder ball adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a chip-scale package which is superior in heat resistance, electric insulation after absorbing moisture, anti-migration characteristic and the like by improving the peeling strength of a solder ball. SOLUTION: This printed wiring board uses a double-sided copper-clad board, having at least 2 or more copper layers with a thickness of 0.2 mm or less as a substrate of a semiconductor chip scale package. At least 2 or more blind holes (b) are formed in a ball pad on the lower surface connected to an upper- surface copper pad by a through-hole conductor, so that a pad (e) for fixing a solder ball on the lower surface connected to the rear side of the upper-surface copper pad by the conductor is electrically connected by a swollen solder ball (c) which is melted and filled in the blind hole. Consequently, the peeling strength of the solder ball is improved by several levels and a printed wiring board for chip-scale package superior in electrical insulation, anti-migration characteristic and the like after subjecting it to pressure cooker treatment is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
For the printed wiring board for chip scale package, which is mounted on a small printed wiring board of almost the same size, the obtained printed wiring board is mounted with a semiconductor chip and used for microcontroller, ASIC, memory, etc. used. 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, a chip scale package (CSP)
As the base material, a thin plate such as a glass epoxy material, a polyimide film material, and a ceramic material is mainly used.
These packages have a solder ball spacing of 0.8m
m or more, the solder ball pitch and circuit line / space have become increasingly narrower in recent years in order to reduce the thickness, size, and weight of the board. And migration resistance have become problems.

In addition, the adhesion of a conventional solder ball such as a plastic ball grid array (P-BGA) or CSP to a substrate becomes smaller as the size of a solder ball pad becomes smaller.
It had become weaker and was the cause of the failure.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for reducing the diameter of a solder ball, which results in poor adhesion of the solder ball to a substrate.
It is still another object of the present invention to provide a printed circuit board for CSP which solves problems relating to heat resistance, electrical insulation after moisture absorption, and migration resistance of a substrate due to thin, small, and lightweight packages.

[0005]

SUMMARY OF THE INVENTION The present invention provides a semiconductor chip scale package having a thickness of 0.1 mm.
Using a double-sided copper-clad board of 2 mm or less, wire bonding or flip-chip bonding terminals for connecting the terminals of the semiconductor chip and the substrate are provided on the copper foil side of the upper surface, and electrically connected to the terminals. A copper pad is provided at a position on the upper surface that can be electrically connected to the blind hole provided on the lower surface, and a solder ball fixing pad is provided on the lower surface at a position corresponding to the copper pad.
More than one blind hole is provided, the solder ball fixing pad on the back side of the upper surface copper pad and the lower surface are connected with conductors,
The present invention also provides a printed wiring board for a chip scale package, wherein the printed wiring boards are electrically connected by solder balls that have been melt-filled into a blind hole and raised. Further, as the resin used for the copper-clad laminate, a polyfunctional cyanate ester and a thermosetting resin composition containing the cyanate ester prepolymer as an essential component are used. According to the present invention, a printed circuit board for CSP that has excellent adhesion to a substrate of a solder ball, and further, by using the above resin, has excellent properties such as heat resistance, electrical insulation after moisture absorption, and migration resistance. Is provided.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a printed wiring board for a chip scale package according to the present invention will be described with reference to FIG. 1 by taking as an example a method in which a semiconductor chip and a printed wiring board are connected by a wire bonding method. 0.2mm thick as substrate for semiconductor chip scale package
The following double-sided copper-clad laminate is used. On one side of the copper clad board,
A wire bonding terminal (1) for connecting a terminal of the semiconductor chip to the substrate is provided. When a semiconductor chip and a printed wiring board are connected by a flip chip method, flip chip bonding terminals (not shown) are provided. A copper pad (a) is provided at a position where the copper pad (a) is connected to the wire bonding terminal and is connected to the lower surface by a blind hole (b) conductor (m). The upper surface copper foil is formed using the copper foil on the upper surface side of the double-sided copper-clad laminate. A solder ball fixing pad (e) is provided around the blind hole (b) on the lower surface side. This fixing pad (e) is formed by using the copper foil on the lower surface side of the double-sided copper clad board. The present invention is characterized in that two or more blind holes are provided in one fixing pad (e). The upper surface side copper pad (a) and the blind hole conductor (m) are electrically connected. The blind hole conductor (m), the copper plating surface (n) on the back side of the upper surface copper pad (a) and the solder ball fixing pad (e) are formed by the solder ball (c) melt-filled in the blind hole (b). It is integrated. The semiconductor chip (i) is made of a heat conductive adhesive such as a silver paste (h)
Is bonded and fixed on the substrate. Semiconductor chip (i) is bonded with bonding wire (j)
(l) is connected. At least the semiconductor chip, the bonding wires and the bonding terminals are sealed with a sealing resin (k).

[0007] The material of the substrate is not particularly limited. For example, a double-sided copper-clad board obtained by attaching a copper foil directly or on both sides of a film with an adhesive, a multilayer board thereof, an organic or inorganic nonwoven fabric, a woven fabric, or the like. One or more prepregs obtained by impregnating and drying the cloth with the thermosetting resin composition are stacked, copper foils are arranged on both sides, and a thickness of 0.1 mm is applied under pressure and heating.
Known materials such as a double-sided copper-clad laminate of 2 mm or less, a multilayer plate thereof, and the like can be used. As the organic fiber, generally known ones such as a liquid crystal polyester and a wholly aromatic polyamide fiber can be used. Examples of the inorganic fibers include generally known glass fibers, and woven and nonwoven fabrics thereof are used. These blends may also be used. As the film, generally known films can be used, and specifically, a polyimide film, a polyparabanic acid film, a polyamide film and the like are used.

A generally known method can be used for forming two or more blind holes in one pad. For example, a method in which a copper foil is preliminarily etched and removed with a small-diameter hole, and a small-diameter via hole is formed in the double-sided copper-clad plate by irradiating a low-energy carbon dioxide gas laser having a low energy of 2 to 18 mJ / pulse, for example, When drilling via holes in copper-clad or multilayer boards with a carbon dioxide gas laser, apply a metal oxide treatment to the laser-irradiated surface, or use a metal oxide powder, carbon, or metal powder with a melting point of 900 ° C and a binding energy of 300 kJ / mol or more. Or a coating material in which a water-soluble resin is mixed, that is, an auxiliary material is applied to form a coating film, or an auxiliary sheet for perforation having an auxiliary material adhered to one surface of a thermoplastic film is disposed, preferably on the auxiliary material side. A method of forming via holes by exposing the surface of the copper foil with a carbon dioxide gas laser and then processing and removing the copper foil, and a method of forming holes with excimer laser and YAG laser. A method of drilling a plasma, generally known drilling methods can be used. The total thickness of the auxiliary material or the auxiliary sheet is preferably 30 to 200 μm.

The resin layer remaining on the copper foil surface at the bottom of the via hole is removed by a generally known removal method such as plasma or desmear, if necessary.

The carbon dioxide gas laser drilling auxiliary sheet of the present invention can be used as it is, but it is necessary to place it on a multilayer board and make it as close as possible when drilling, in order to improve the hole shape. preferable. In general, the sheet is fixed and adhered to the multilayer board by a method such as affixing it with a tape or the like, but in order to more completely adhere, the obtained sheet is double-sided copper-clad board, multilayer board. To the surface of the copper foil surface, facing the surface with the resin attached, heating and laminating under pressure, or after pre-wetting the resin surface layer 3 μm or less with moisture, laminating under pressure at room temperature, Has good adhesiveness and a good hole shape can be obtained.

As the resin composition, a resin composition which is not water-soluble and can be dissolved in an organic solvent can also be used. However, the carbon dioxide laser irradiation may cause the resin to adhere around the holes, and the removal of the resin requires an organic solvent instead of water, which is troublesome in processing, and also causes contamination in a post-process. It is not preferable because it causes problems.

As the resin of the thermosetting resin composition used as the substrate used in the present invention or as a part thereof, 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 point of the through hole shape in processing by high output carbon dioxide laser irradiation,
A thermosetting resin composition having a glass transition temperature of 150 ° C. or higher is preferred, and a polyfunctional cyanate resin composition is preferred from the viewpoints of moisture resistance, migration resistance, electrical properties after moisture absorption, and the like.

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 a 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-cy (Anatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting novolak with cyanogen halide. In addition to these,
8, 43-18468, 44-4791, 45-11712, 46-41112,
Polyfunctional cyanate compounds described in JP-A-47-26853 and JP-A-51-63149 can also be used. Further, the molecular weight of the polyfunctional cyanate compound having a triazine ring formed by trimerization of a cyanato group of the polyfunctional cyanate compound is 400.
~ 6,000 prepolymers are 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. A generally known polyimide resin 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 organic fillers, dyes,
Pigments, thickeners, lubricants, defoamers, dispersants, leveling agents,
Various additives such as a photosensitizer, a flame retardant, a brightener, a polymerization inhibitor, and a thixotropy-imparting agent are used in an appropriate combination as required. If necessary, the compound having a reactive group is appropriately blended with a curing agent and a catalyst.

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 auxiliary material used in the present invention has a melting point of 90.
As the metal compound having a binding energy of 300 kJ / mol or more at 0 ° C. or more, generally known metal compounds can be used. Specifically, as the oxide, titania such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, manganese dioxide, zinc oxide such as zinc oxide , Silicon oxide, aluminum oxide, rare earth oxides, cobalt oxides such as cobalt oxide, tin oxides such as tin oxide, and tungsten oxides such as tungsten oxide. Examples of the non-oxide include generally known ones such as silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, and rare earth oxysulfide. In addition, carbon can also be used. Further, various glasses which are a mixture of the metal oxide powders may be mentioned. In addition, carbon powder may be mentioned, and furthermore, a simple substance such as silver, aluminum, bismuth, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, zinc, or an alloy thereof Metal powder is used. These may be used alone or in combination of two or more. The average particle size is not particularly limited, but is preferably 1 μm or less.

It is preferable that the molecules are not dissociated by the irradiation of the carbon dioxide gas laser or are melted and scattered so that the metal adheres to the hole walls or the like and does not adversely affect the semiconductor chip and the hole wall adhesion. . Since Na, K, Cl ions and the like particularly adversely affect the reliability of the semiconductor, those containing these components are not suitable. The compounding amount is 3 to 97 vol%, preferably 5 to 95 vol%, and is preferably mixed with the water-soluble resin and uniformly dispersed. The water-soluble resin of the auxiliary material is not particularly limited, but a resin that does not peel off when kneaded and applied to the surface of the copper foil and dried or when formed into a sheet is selected. For example, generally known materials such as polyvinyl alcohol, polyester, polyether and starch are used.

The method for preparing the metal compound powder, the carbon powder, or the composition comprising the metal powder and the resin is not particularly limited, but is kneaded at a high temperature without a solvent in a kneader or the like, and extruded into a sheet on a thermoplastic film. A method of dissolving a water-soluble resin in water, adding the powder to the mixture, stirring and mixing the mixture uniformly, and applying the mixture to a thermoplastic film as a paint, followed by drying to form a film. And other generally known methods. Although the thickness is not particularly limited, it is generally used in a total thickness of 30 to 200 μm after drying. In addition, it is possible to similarly form a hole after performing a metal oxide treatment on the copper foil surface, but it is more preferable to use the above-mentioned auxiliary material also from the viewpoint of the hole shape and the like. When laminating under heat and pressure on the copper foil surface, the coating resin layer is directed to the copper foil surface, and with a roll, the temperature is generally 40 to 150 ° C, preferably 60 to 120 ° C.
In general, lamination is performed at a linear pressure of 5 to 30 kgf, preferably 10 to 20 kgf, and the resin layer is melted and brought into close contact with the copper foil surface. The selection of the temperature depends on the melting point of the water-soluble resin used, and also depends on the linear pressure and the laminating speed. In general, lamination is performed at a temperature higher by 5 to 20 ° C. than the melting point of the water-soluble resin. In the case of close contact at room temperature, the surface of the coating resin layer of 3 μm or less is moistened with water before lamination to dissolve a small amount of the water-soluble resin, and is laminated under the same pressure. The method of moistening with moisture is not particularly limited, for example, a method of continuously applying moisture to the coating resin surface with a roll, and then continuously laminating the surface of the copper-clad laminate,
A method in which water is continuously sprayed on the surface of the coating film in a spraying manner, and then continuously laminated on the surface of the copper-clad laminate may be used.

The substrate-reinforced multilayer board is first impregnated with the thermosetting resin composition and dried to form a B stage,
Create a prepreg. Next, a predetermined number of the prepregs are stacked, a copper foil is arranged on at least one side, and laminated under heat and pressure to form a copper-clad laminate. The thickness of the copper foil on both sides is preferably 5 to 18 μm. The inner layer copper foil is preferably 18
7070 μm. The multilayer board forms a circuit on the copper-clad laminate reinforced with the base material, and after the copper foil surface treatment, at least one side has B
Stage base reinforced prepreg, or resin sheet without substrate reinforcement, copper foil with resin, resin layer by paint application, etc., if necessary, place copper foil on the outside, heat, press, preferably A copper-clad multilayer board laminated and formed under vacuum is used. It is preferable that the base material be thin and have a high density. For example, for a 50 μm glass woven substrate, 5
And 0~60g / m ^2.

The diameter of the solder ball pad on the back side is generally
200 to 500 μm, in which two or more holes are drilled.
The hole diameter is not particularly limited, but is generally 50 to 150 μm when a high-density printed wiring board is prepared. Drilling is preferably performed with a high power carbon dioxide laser with an auxiliary material placed on the surface. A blind hole is formed by drilling, but even if part of the copper foil on the facing side is pierced, all or most of the facing hole will be filled by the subsequent panel plating, so the subsequent production of a printed wiring board Has no effect. When an auxiliary material is placed on the surface of a copper-clad plate and holes are drilled by directly irradiating laser energy of, for example, 20 to 60 mJ / pulse, burrs of copper foil occur around the holes. When a very high-density circuit is required, it is necessary to make the surface copper foil thin, and preferably, after irradiation with a carbon dioxide gas laser, both surfaces of the copper foil are planarly etched mechanically or with a chemical solution. By removing a part of the thickness of the original metal foil, burrs are also removed at the same time. The obtained copper foil is suitable for forming a fine pattern, and can form a via hole in which a copper foil around a hole suitable for a high-density printed wiring board remains. in this case,
Etching is preferable to mechanical polishing in that it is easier to remove burrs at the holes and the dimensional change due to polishing is less.

The method of etching and removing copper burrs generated in the holes according to the present invention is not particularly limited. For example, Japanese Patent Application Laid-Open Nos. 02-22887, 02-22896, 02-25089 and 02-2.
5090, 02-59337, 02-60189, 02-166789, 03-25
995, 03-60183, 03-94491, 04-199592, 04-263
No. 488 discloses a method of dissolving and removing a metal surface with a chemical (referred to as a SUEP method). The etching rate is generally 0.02 to 1.0 μm / sec.

When drilling a via hole with a carbon dioxide laser,
It is also possible to irradiate energy selected from 20 to 60 mJ / pulse from the beginning to the end. However, when first removing the copper foil of the surface layer and the inner layer, the copper foil is removed by selecting higher energy, and the bottom of the hole is 5 to 3 depending on the thickness of the copper foil.
It is preferable to perform drilling by irradiating energy selected from 5 mJ / pulse. In drilling, it is also possible to change the processing conditions when there is an inner copper foil inside the hole and when there is no inner layer copper foil. As the copper plating, generally known copper plating can be performed. Further, the inside of the blind hole may be partially filled with plating.

[0024]

The present invention will be specifically described below based on 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
Parts, mixed and dissolved, 500 parts of an inorganic filler (trade name: calcined talc BST- # 200, manufactured by Nippon Talc Co., Ltd.), and 8 parts of black pigment were added, and the mixture was uniformly stirred and mixed to obtain varnish A. Obtained. The varnish was impregnated with a glass woven cloth having a thickness of 50 μm (weight: 53 g / m ² ), dried at 150 ° C., and gelled for 120 minutes at at 170 ° C.
Prepreg with a resin composition content of 51 wt% (prepreg
B) was created. Electrodeposited copper foil having a thickness of 12 μm is placed above and below 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, and a double-sided copper-clad laminate C having a total thickness of 134 μm is formed. I got

On the other hand, a varnish prepared by dissolving polyvinyl alcohol powder in water was added to 800 parts of talc (average particle size: 0.4 μm, trade name: BST # 200), and the mixture was uniformly stirred and mixed. This was applied on one side of a polyethylene terephthalate film having a thickness of 50 μm so as to have a thickness of 30 μm.
After drying for a minute, an auxiliary material D with a talc content of 40 vol% was formed. On the above-mentioned copper clad laminate, it was arranged so that the resin surface faced the copper foil side, and was heat-pressed with a hot roll at 100 ° C. Hole diameter 1
One hundred μm holes were made in a 7 mm square with a direct carbon dioxide laser at a power of 40 mJ / pulse and one shot was made in the copper foil. Next, the output was set to 20 mJ / pulse, and one shot was taken.
/ Pulse irradiates one shot, and three holes of 100 μm are equally formed in a 300 μm diameter solder ball pad [Fig.
b]. Perform a SUEP treatment, dissolve the copper foil to a residual thickness of 5 μm, put it in a plasma device, and in an oxygen atmosphere for 10 minutes,
Further, a treatment was performed for 5 minutes in an argon atmosphere to remove the residual resin layer inside the via hole and remove the surface layer of the front and back copper foils to obtain a thickness of 4 μm. This was put in an aqueous solution of potassium permanganate, wet-treated in an ultrasonic wave, and then subjected to ordinary electroless and electrolytic copper plating on the plate [FIG. 1-f, m]. The surface is soft-etched to form a circuit (200 lines / space = 50/50 μm) on the front and back by the existing method, and at least a semiconductor chip portion and a bonding pad portion [FIG.
l], except for the solder ball pad portion (FIG. 1-e), coating with a plating resist [FIG. 1-g], and plating with nickel and gold [FIG. 1-1] to produce a printed wiring board. A semiconductor chip (FIG. 1-I) is adhered and fixed to this with a silver paste (FIG. 1-h), connected to a bonding pad (FIG. 1-1) with a bonding wire (FIG. 1-j), and a sealing resin [FIG. 1-k]. Further, a solder ball [FIG. 1-c] was melt-bonded.
Table 1 shows the evaluation results of the printed wiring board.

Example 2 700 parts of an epoxy resin (trade name: Epikote 5045), 300 parts of an epoxy resin (trade name: ESCN-220F), 35 parts of dicyandiamide, and 1 part of 2-ethyl-4-methylimidazole were mixed with methyl ethyl ketone and dimethyl. It was dissolved in a mixed solvent of formamide, uniformly stirred and mixed. This was impregnated into the same glass cloth as in Example 1 and dried to prepare a prepreg E having a gelation time of 150 seconds. Use three prepregs E,
190 ° C., and laminate molding under vacuum of below 20kgf / cm ^2, 30mmHg,
A 189 μm-thick double-sided copper-clad laminate was prepared. Similarly, hole diameter 1
Three blind holes of 25 μm were made, and the holes were filled with 27% by volume by pulse plating (Nihon Renonal method). Thereafter, a printed wiring board was prepared in the same manner, and solder balls were connected. Table 1 shows the evaluation results of the printed wiring board.

Comparative Examples 1 and 2 A printed wiring board was prepared in the same manner as in Example 1 except that 0 or 1 blind hole having a hole diameter of 100 μm was formed in the solder ball pad. Table 1 shows the evaluation results.

Comparative Example 3 A prepreg was prepared in the same manner as in Example 2 except that a glass cloth having a weight of 48 g / cm ² was used.
Two sheets were similarly laminated and formed into a double-sided copper-clad laminate. A hole was not made in the solder ball pad, and thereafter, a printed wiring board was prepared and evaluated in the same manner. Table 1 shows the results.

[0029]

[Table 1]

Note: Glass transition temperature: ° C., ball shear strength: kgf, viscoelasticity: × 10 ¹⁰ dyne / cm ² .

<Measurement method> 1) Glass transition temperature Measured by a DMA method. 2) Ball shear strength measurement It was measured by pulling from the side. 3) Measured by DMA. 4) Insulation resistance value after pressure cooker processing Create a comb pattern of line / space = 50 / 50μm,
Place the used prepreg on this,
After laminating and molding, it is treated at 121 ° C. and 2 atm for a predetermined period of time, then post-treated at 25 ° C. and 60% RH for 2 hours, and 500 VDC is applied for 60 hours.
Seconds later, the insulation resistance between the terminals was measured. 5) Migration resistance The test piece of 4) was applied at 85 ° C. and 50 VDC, and the insulation resistance between the terminals was measured. 6) Blind hole heat cycle test Connect 100 pads with each blind hole,
Cycle is 260 ℃, solder immersion 30 seconds → room temperature 5 minutes 200 cycles,
The maximum value of the rate of change of the resistance value is shown.

[0032]

According to the printed wiring board for a semiconductor chip scale package of the present invention, there is provided a printed wiring board in which the shear strength of solder balls is greatly improved. ,
Furthermore, by using a polyfunctional cyanate ester and the cyanate ester prepolymer as a resin for the copper-clad laminate, it is used for chip scale packages with excellent heat resistance, electrical insulation after pressure cooker treatment, migration resistance, etc. A printed wiring board is provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating three ball diameters of the ball pad of Example 1.
FIG. 4 is an explanatory view showing a joint state between a 1 mm blind hole and a 0.3 mm solder ball.

[Explanation of symbols]

 a Copper foil pad on upper surface b Blind hole of 100 μmφ c Solder ball d Glass cloth base thermosetting resin layer e Solder ball pad on lower surface f Copper plating g Plating resist h Silver paste i Semiconductor chip j Bonding wire k Sealing resin l Bonding terminal m Blind hole conductor n Copper-plated surface behind top pad

Claims (2)

[Claims] 1. A double-sided copper-clad plate having a thickness of 0.2 mm or less is used as a substrate of a semiconductor chip scale package, and wire bonding or flipping for connecting a terminal of the semiconductor chip and the substrate is provided on a copper foil side on an upper surface. A copper pad is provided at a position where a chip bonding terminal is provided and electrically connected to the terminal and electrically connectable to a blind hole provided on the lower surface, and a solder ball is fixed on a lower surface at a position corresponding to the copper pad. A pad is provided, two or more blind holes are provided in the solder ball fixing pad, and the solder ball fixing pad on the lower surface connected to the back side of the upper surface copper pad and the conductor is melt-filled into the blind hole and raised. A printed wiring board for a chip scale package, wherein the printed wiring board is electrically connected by solder balls. 2. The insulating layer of the copper clad board is formed by impregnating an organic or inorganic base material with a polyfunctional cyanate ester and a thermosetting resin composition containing the cyanate ester prepolymer as an essential component, followed by drying. The printed wiring board according to claim 1, which is a laminate obtained by laminating prepregs obtained by lamination.