JPH11214572A - Method for producing double-sided metal foil-clad multilayer board with metal core - Google Patents

Abstract

(57) [Problem] To provide a double-sided metal foil-clad laminate for a multilayer semiconductor plastic package excellent in heat dissipation, heat resistance after moisture absorption and the like. SOLUTION: This is a multilayer semiconductor plastic package of a ball grid array using a double-sided metal foil-clad laminate containing a metal core, wherein a part of the metal core is exposed on a part of the surface and is fixed thereon. A semiconductor plastic package in which a semiconductor chip and its surrounding circuit conductors are connected by wire bonding, front and back circuits are connected to a metal core by through holes, and the semiconductor chip portion is resin-sealed. [Effect] A multi-layer semiconductor plastic package having a novel structure that is excellent in heat dissipation and heat resistance after moisture absorption and is suitable for mass productivity can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a double-sided metal foil-clad multilayer board for use in a novel semiconductor plastic package in which a semiconductor chip is mounted on a small printed wiring board. In particular, the present invention relates to a method for producing a double-sided metal foil-clad multilayer board for use in a semiconductor plastic package having a relatively high wattage and a high density of terminals such as a microprocessor, a microcontroller, an ASIC, and a graphic. The present semiconductor plastic package connects a semiconductor chip and a circuit conductor of a printed wiring board by wire bonding, and is mounted on a motherboard printed wiring board using solder balls and used as an electronic device.

[0002]

2. Description of the Related Art Conventionally, a chip is fixed on the upper surface of a plastic printed wiring board such as a plastic ball grid array (P-PGA) or a plastic land grid array (P-LGA) as a semiconductor plastic package, and the chip is printed. Bonded to the conductor circuit formed on the upper surface of the board by wire bonding, and formed solder pads on the lower surface of the printed wiring board to connect to the motherboard printed wiring board, and the front and back circuit conductors were plated 2. Description of the Related Art A semiconductor plastic package having a structure in which semiconductor chips are sealed with a resin and connected by through holes is known. In this known structure, in order to diffuse heat generated from the semiconductor to the motherboard printed wiring board,
A plated thermal diffusion through-hole is formed from the upper metal foil for fixing the semiconductor chip to the lower surface.

[0003] Water is absorbed by the resin adhesive containing silver powder used for fixing the semiconductor through the through-hole, and is heated by mounting when mounting on the motherboard and by heating when removing the semiconductor component from the motherboard. There is a risk of blistering, which is called the popcorn phenomenon. When this popcorn phenomenon occurs, the package often becomes unusable, and it is necessary to greatly improve this phenomenon. In addition, higher functionality and higher density of semiconductors mean more and more heat generation, and heat dissipation is insufficient with only through holes directly below the semiconductor chip for heat dissipation. Conventionally, these printed wiring boards for mounting semiconductor chips are prepared using a double-sided copper-clad laminate obtained by laminating and molding using a prepreg of a glass woven fabric base material inside and copper foil on both sides. Therefore, the structure described above must be adopted.

[0004]

SUMMARY OF THE INVENTION The present invention is to provide a double-sided metal foil-clad multilayer board for producing a printed wiring board for a semiconductor plastic package which has solved the above-mentioned problems.

[0005]

That is, according to the present invention, a metal plate having substantially the same size as a printed wiring board is disposed substantially at the center in the thickness direction of the printed wiring board. At least a part of at least one metal plate is exposed in a protruding manner, and a semiconductor chip is fixed thereon, and the semiconductor chip is bonded to a circuit conductor formed on a surface of a printed wiring board around the semiconductor chip by wire bonding. Connected, at least the signal propagation circuit conductor on the printed wiring board on the front surface is a circuit conductor formed on the opposite surface of the printed wiring board or a through-hole conductor plated with a conductor pad for connection with the solder ball Use a printed wiring board that has at least one through hole directly connected to the inner metal core. In the method of manufacturing a double-sided metal foil-clad multilayer board for a semiconductor plastic package having a structure in which a bonding pad is sealed with a resin (FIG. 1), (1) a metal plate to be used for a metal core is prepared, and An etching resist is formed. (2) Etching is performed to form a projection on one side on which a semiconductor chip is mounted. (3) A liquid etching resist is applied to the entire surface of the metal plate again and dried, and then the surface is covered with a negative film punched out of a metal projection and irradiated with ultraviolet rays. (4) 1% resist in the unexposed clearance hole
After dissolving and removing with a sodium carbonate solution and etching from both sides to form a clearance hole, the etching resist is removed. (5) The prepreg sheet on the side having the metal protrusions is provided with a low-flow or no-flow prepreg sheet, a resin sheet, or a coating resin layer in which holes slightly larger than the area of the prepreg sheets are formed at the positions of the protrusions. A high-flow prepreg sheet, a resin sheet, and a resin, on which a circuit is formed on one side and a double-sided board or a multilayer board whose surface is chemically treated if necessary, and a resin flow and a resin flow sufficient to embed clearance holes are placed on the other side. A copper foil or a coated resin layer is arranged, and a metal foil or a single-sided copper-clad laminate is placed on the outside of the copper foil or a single-sided copper-clad laminate, if necessary. A double-sided metal-foil-clad multi-layer board with a metal core having a metal projection exposed on one side, characterized in that it is a multi-layer board with a metal core for a semiconductor plastic package. This is a method for manufacturing a multilayer board.

[0006] Using the double-sided metal foil-clad multilayer board with a metal core produced above, (7) a drill,
Drill a through hole slightly smaller than the conductor diameter of the clearance hole with a laser, etc., the hole wall and the metal plate are insulated with a resin composition, and at least one through hole is connected to the metal plate for heat dissipation. (8) Circuits are formed on the front and back sides, and (9) At least parts other than the metal pad for fixing the bonding pad, the solder ball pad, and the semiconductor chip are covered with a plating resist. , Nickel, and gold plating to make a printed wiring board, and a semiconductor chip is bonded and fixed to a metal projection of the printed wiring board with a metal powder mixed conductive-heat conductive adhesive, wire bonding, and resin sealing. By applying solder balls, a multilayer semiconductor plastic package is obtained.

The resulting semiconductor plastic package does not absorb moisture from the lower surface of the semiconductor, can greatly improve the popcorn phenomenon, and has a heat resistance and a post-pressure cooker treatment by using a polyfunctional cyanate resin composition. Was excellent in electrical insulation, migration resistance and the like, and the heat dissipation was also significantly improved. In addition, a semiconductor plastic package having a novel structure which is suitable for mass productivity and has improved economic efficiency was obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A semiconductor plastic package using a double-sided metal foil-clad multilayer board with a metal core according to the present invention has a metal plate with good heat dissipation disposed at substantially the center in the thickness direction of a printed wiring board. The plated through hole for conducting the circuit conductor is a hole with a diameter larger than the diameter of the through hole drilled in the metal plate, and it is formed almost at the center of the embedded resin, so that the insulation with the metal plate Hold.

In a known method of fixing a semiconductor chip on the upper surface of a metal-core printed wiring board having a through hole, heat from the semiconductor chip is dropped to a heat-dissipating through hole immediately below, similarly to a conventional P-BGA package. Heat must be dissipated and the popcorn phenomenon cannot be improved. The printed wiring board for a semiconductor plastic package prepared using the double-sided metal foil-clad multilayer board obtained by the present invention has at least one or more metal projections for fixing the semiconductor chip with a heat conductive adhesive exposed on the surface. There is a clearance hole larger than the through hole diameter at the position where the through hole is to be formed, and a through hole smaller than the clearance hole diameter is formed almost at the center of this clearance hole, and the front and back circuit is conducted by plating Has been
In addition, since at least one or more through holes are directly connected to the inner metal plate, the heat generated from the semiconductor in the plastic package in which the semiconductor chip is fixed, wire-bonded, and resin-sealed is directly Since the heat is conducted from the mounted metal part to the entire metal plate, it is transmitted to the metal pad on the lower surface through a through hole connected to this metal plate from a place other than immediately below the semiconductor chip, and diffused to the motherboard printed wiring board I do.

Although the metal plate used in the present invention is not particularly limited, a metal plate having a high elastic modulus, a high thermal conductivity and a thickness of 30 to 400 μm is preferable. Specifically, pure copper, oxygen-free copper, and others,
An alloy of 95% or more of copper with Fe, Sn, P, Cr, Zr, Zn, or the like, or a metal plate in which the surface of an alloy such as 42 alloy is copper-plated is preferably used. It is also possible to bond a uniform or different metal plate of a predetermined size on a smooth metal with a copper paste or the like having good heat conductivity.

According to the present invention, at least one semiconductor chip is fixed to a metal plate serving as a metal core by a known etching method, a cold machining method, a rolling irregular shape processing method, or the like. A projection approximately the same size as the chip is formed. It is also possible to form a projection by bonding a metal plate having substantially the same size as a semiconductor chip on a smooth metal plate with an adhesive or the like having good heat conductivity. The size of the projection is generally 5 to 20 mm square.

The height of the metal projection of the present invention is 100 to 250.
μm is preferred. Also, the height of the thermosetting resin layer formed by low-flow or no-flow prepreg, a resin sheet, or screen printing, etc.
The height combined with the height of the double-sided metal foil laminate or the double-sided metal foil multilayer board used thereon is slightly higher than the height of the metal projection.

A clearance hole slightly larger than the through hole is formed in the metal plate by a known method such as etching, drilling, punching, and UV laser. In particular,
The through hole wall and the metal plate clearance hole wall are:
It is preferable that the distance of 50 μm or more is insulated by a thermosetting resin. Generally, it is 70 to 200 μm. Although there is no particular limitation on the diameter of the through-hole for conducting the front and back circuits, the diameter is smaller than the clearance hole, generally 50 to
300 μm.

The entire metal plate is preferably subjected to a surface chemical treatment before lamination. Specifically, a generally known treatment such as a black oxidation treatment, a brown treatment, and a surface roughening treatment with a chemical may be performed.

As the resin of the thermosetting resin composition used in the present invention, generally known thermosetting resins are used.
Specific examples include an epoxy resin, a polyfunctional cyanate resin, a polyfunctional maleimide-cyanate resin, a polyfunctional maleimide resin, and a polyphenylene ether resin having an unsaturated group. Are used in combination. Polyfunctional cyanate ester resin compositions are preferred from the viewpoints of heat resistance, 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 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 43-184
68, 44-4791, 45-11712, 46-41112, 47-26853
And polyfunctional cyanate compounds described in JP-A-51-63149 and the like can also be used. In addition, a prepolymer having a molecular weight of 400 to 6,000 and having a triazine ring formed by trimerizing a cyanato group of these polyfunctional cyanate compounds is used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer using, for example, an acid such as a mineral acid or a Lewis acid; a base such as a sodium alcoholate or a tertiary amine; a salt such as sodium carbonate as a catalyst. 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 group-containing silicone resin with an ephalohydrin, and the like. These can 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, fluoro rubber, natural rubber; polyethylene, polypropylene,
Polybutene, poly-4-methylpentene, polystyrene,
AS resin, ABS resin, MBS resin, styrene-isoprene rubber, polyethylene-propylene copolymer, 4-fluoroethylene-6-fluoroethylene copolymers; polycarbonate, polyphenylene ether, polysulfone, polyester, polyphenylene sulfide, etc. High molecular weight prepolymers or oligomers; polyurethanes and the like are exemplified, and are appropriately used. Other known inorganic or organic fillers, dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents, photosensitizers, flame retardants, brighteners, polymerization inhibitors, thixotropic Various additives such as imparting agents are used in combination as needed. 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.

As the reinforcing base material of the prepreg, generally known inorganic or organic woven or nonwoven fabric is used. Specific examples include known glass fiber cloths such as E glass, S glass, and D glass, wholly aromatic polyamide fiber cloths, and liquid crystal polyester fiber cloths. These may be mixed. Alternatively, a thermosetting resin composition applied to the front and back of a film such as a polyimide film and heated to a semi-cured state can be used.

As the metal foil of the outermost layer or the metal foil of the single-sided metal-clad laminate, generally known ones can be used. Preferably thickness 3
Copper foil, nickel foil, etc. of up to 100 μm are used. Also,
On one side of the double-sided metal-clad laminate or double-sided metal foil-clad multilayer board used for the surface, a circuit is formed, and the metal projection is punched out slightly larger than the area of the projection, and a chemical surface treatment is performed if necessary.

When preparing the prepreg for a multilayer printed wiring board of the present invention, a base material is impregnated with a thermosetting resin composition and dried to obtain a semi-cured laminated material. In addition, resin is applied to semi-cured resin sheet and copper foil without using base material,
Dry and semi-cured products can be used. Alternatively, paints can be used. In this case, depending on the degree of the semi-cured state, high flow, low flow, or no flow is used. In case of no flow, when heating and pressurizing and laminating,
The flow of the resin is 100 μm or less, preferably 50 μm or less. At this time, it is important that the copper plate and the copper foil adhere to each other and no void is generated. In the case of high flow, the resin flowing out when laminated by heating and pressing is 2 mm or more, preferably 10 mm or more. This intermediate resin flow is referred to as low flow. The heating temperature is generally between 100 and 180 ° C. The time is 5 to 60 minutes, and is appropriately selected depending on the desired flow rate.

Since the heat generated from the semiconductor is conducted from the metal part directly mounted to the entire metal plate, the plated through hole is formed at least on the metal core and the metal pad on the lower surface from a place other than immediately below the semiconductor chip. One or more holes are formed to diffuse heat from the semiconductor chip to the motherboard printed wiring board.

The surface of the metal plate on which the projections and the through holes are formed is subjected to a surface treatment for improving adhesiveness and electric insulation such as oxidation treatment, formation of fine irregularities, and formation of a film by a known method, if necessary. . Except for the surface of the metal plate on which the projections and the clearance holes are formed and on which the semiconductor chip is directly fixed, the insulating portion is formed of a thermosetting resin composition.

The insulating portion is formed from the thermosetting resin composition in a semi-cured state so that when the base material is impregnated with the thermosetting resin composition and laminated and formed, the resin does not flow into the metal protrusions due to the resin flow. Using a low-flow prepreg, a no-flow prepreg, a film-like sheet, etc., place a hole in which a hole slightly larger than the area of the metal part with the protrusion for directly fixing the semiconductor chip is punched out in advance, etc. A circuit is formed on a metal foil on one side of a double-sided metal foil-clad laminate or a double-sided metal foil-clad multilayer board, and a chemical surface treatment is applied if necessary, and the circuit surface is placed on the prepreg side. The resin flows into the clearance hole during lamination molding to cover the entire surface on the opposite side of the plate, and the amount of resin that can be sufficiently filled and the high flow prepreg of resin flow DOO, a resin sheet overlaid with resin such as copper foil, a metal foil, if necessary on the outside, or placed on one side metal foil-clad laminate, heating, pressing, laminate molding under vacuum. The thickness of the prepreg sheet and the film-like sheet on the surface is made slightly higher than the height of the metal projections.
During the heating and pressurizing steps, a small amount of semi-cured thermosetting resin melted once by heat is poured from the front surface into the clearance hole of the metal plate, from the back surface, and from the back surface to fill the clearance hole. The other parts than the surface of the metal projection are integrated with the thermosetting resin composition.

Further, using a non-solvent or solvent type thermosetting resin composition, apply by screen printing or the like to places other than the metal plate projections. Then, it is cured by heating as it is, or is laminated and formed under heat and pressure to be integrated. The semi-cured state of the resin on the metal protrusion side is adjusted by heating so as to have a low-flow or no-flow when laminated and formed.
The back surface is high flow. A metal foil or a single-sided metal foil-clad laminate is placed on both outer sides, and when laminating and molding under heat and pressure, preferably under vacuum, the resin is poured into the clearance holes and thermally cured at the same time as described above. In the case of applying, a resin is poured into the clearance hole at a low pressure, and the solvent or air is removed while heating, and semi-cured or cured. If a solvent is contained, unfilling in the clearance hole is likely to occur, so it is poured into the solvent-free liquid thermosetting resin composition clearance hole in advance,
The method of hardening is common. In either method, processing is performed so that the inside of the clearance hole of the metal plate is filled with the thermosetting resin composition.

The side surface of the metal plate may be either a shape embedded with the thermosetting resin composition or an exposed shape.

Noble metal plating for wire bonding is formed on at least the surface of the wire bonding pad on the front and back circuits to complete the printed wiring board. In this case, a portion that does not require noble metal plating is covered with a plating resist in advance. After plating, if necessary, a film is formed on the surface with a known thermosetting resin composition or a photo-selective thermosetting resin composition.

A semiconductor chip is fixed to the surface of the metal projection portion of the printed wiring board using an adhesive or a metal powder mixed adhesive, and the semiconductor chip is connected to a bonding pad of a printed wiring board circuit by a wire bonding method. Then, at least the semiconductor chip, the bonding wires, and the bonding pads are sealed with a known sealing resin.

A solder ball is connected to the solder ball connection conductor pad on the opposite side of the semiconductor chip to form a P-BGA, and the solder ball is superimposed on a circuit on a motherboard printed wiring board, and the ball is melt-connected by heat. When the P-LGA is made without attaching solder balls to the package, and mounted on the motherboard printed wiring board, the solder ball connection conductor pads formed on the motherboard printed wiring board surface and the solder ball conductors for the P-LGA The pads are connected by heating and melting the solder balls.

[0034]

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 and 100 parts of bis (4-maleimidophenyl) methane were melted at 150 ° C. and reacted with stirring for 4 hours to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. 400 parts of bisphenol A type epoxy resin (trade name: Epicoat 1001, manufactured by Yuka Shell Epoxy Co., Ltd.) and cresol novolac type epoxy resin (trade name: ESCN-220F, manufactured by Sumitomo Chemical Co., Ltd.)
600 parts were added and uniformly dissolved and mixed. Further, 0.4 part of zinc octylate is added as a catalyst, and the mixture is dissolved and mixed. The resulting mixture is mixed with an inorganic filler (trade name: calcined talc BST-200, Nippon Talc Co., Ltd.)
Was added and mixed uniformly with stirring to obtain Varnish A.

The varnish was impregnated with a glass woven fabric having a thickness of 100 μm, dried at 150 ° C., and gelled (at 170 ° C.) for 7 seconds.
A semi-cured low-flow prepreg (prepreg B) having a thickness of 110 μm was prepared so that the resin flow was 110 μm in 170 ° C., 20 kgf / cm ² for 5 minutes. Also dried at 145 ℃, gel time (at 170 ℃) 120 seconds, resin flow 13 mm, thickness
A 107 μm high flow prepreg (prepreg C) was prepared.

On the other hand, a 400 μm thick C
Prepare alloy consisting of u: 97.45%, Fe: 2.4%, P: 0.03%, Zn: 0.12%, 13mm in the center of 50mm square package
A protrusion having a corner and a height of 220 μm was formed by an etching method.
After that, a liquid etching resist having a thickness of 25 μm was applied to the entire surface of the metal plate, dried, and the solvent was blown off. After that, a negative film having a protruded portion was layered, and a negative film was applied to the entire lower surface, and a clearance hole was applied. Then, the resist film in the clearance hole was removed with a 1% aqueous solution of sodium carbonate, and then a 0.6 mmφ clearance hole was formed by etching from both sides.

A black copper oxide treatment is applied to the entire surface of the metal plate.
The prepreg B, in which a hole larger in μm was punched, was covered, and the prepreg C was placed on the lower side. In addition, 12μm electrolytic copper foil was placed on both sides of prepreg C, a circuit was formed on one side of the double-sided copper-clad laminate similarly laminated, and a slightly larger hole was punched in the semiconductor chip mounting portion by punching. Copper oxide treatment is applied, and the circuit forming surface is placed on the front side with the circuit forming surface facing down. A 12 μm electrolytic copper foil is placed outside the prepreg on the back surface, and is placed under vacuum at 200 ° C., 20 kgf / cm ² , 30 mmHg or less. A double-sided copper-clad multilayer board with metal projections exposed on the surface was obtained by lamination molding for one hour.

The clearance hole has a hole diameter of 0.25 mm at the center so as not to contact the metal of the clearance hole.
Drill the through holes in the hole.The heat dissipating points are drilled at the four corners with a hole diameter of 0.25 mm so as to directly contact the metal plate.After desmearing, copper plating is performed by electroless and electrolytic plating. A copper plating layer of 18 μm was formed therein. After applying and drying a liquid etching resist on the front and back, a positive film was overlaid and exposed and developed to form a front and back circuit.
A plating resist was formed on portions other than the protruding portion, the bonding pad portion, and the ball pad portion, and plated with nickel and gold to complete a printed wiring board.

A semiconductor chip having a size of 13 mm square is adhered and fixed to the protruding portion with a silver paste, wire-bonded, and then resin-encapsulated by transfer molding using an epoxy encapsulating compound containing silica to form a solder ball. To make a semiconductor package (Fig. 1). This was connected to an epoxy resin mother board printed wiring board by melting solder balls. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 1 Two prepregs C of Example 1 were used, and 12 μm electrolytic copper foils were arranged on the upper and lower sides, and laminated and molded at 200 ° C., 20 kgf / cm ² , and 30 mmHg or less for 2 hours. A copper-clad laminate was obtained. Drill a through hole with a hole diameter of 0.25 mmφ at a predetermined position,
Copper plating was performed after the desmear treatment. Circuits were formed on and under the plate by a known method, plating resist was applied, and nickel plating and gold plating were applied. This has a through hole for heat radiation under the place where the semiconductor chip is mounted, the semiconductor chip is bonded with silver paste on this, and after wire bonding, the epoxy sealing compound is used in the same way as in Example 1. It was sealed with resin and solder balls were attached (Fig. 2). Also connected to the motherboard in the same way. Table 1 shows the evaluation results of the semiconductor plastic package.

Comparative Example 2 500 parts of an epoxy resin (trade name: Epicoat 1045), 500 parts of an epoxy resin (trade name: ESCN220F), 300 parts of dicyandiamide, and 2 parts of 2-ethylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. Then, this was impregnated into a glass woven fabric having a thickness of 100 μm, and a gel time (at 170 ° C.) of 10 seconds, a no-flow prepreg (prepreg D) having a resin flow of 98 μm, a gel time of 150 seconds, and a resin flow of 18
mm high flow prepreg (prepreg E) was prepared.

Using two prepregs E, 170 ° C., 20 kgf
Laminate molding was carried out for 2 hours under a vacuum of 30 mmHg / cm ² to produce a double-sided copper-clad laminate. After that, a printed wiring board was created in the same manner as in Comparative Example 1, and a semiconductor chip mounting portion was cut out with a counterbore machine, and then a copper plate having a thickness of 200 μm was punched out on the back surface using the above-mentioned no-flow prepreg D. Then, they were similarly bonded under heat and pressure to prepare a printed wiring board with a heat sink. This slightly warped. A semiconductor chip was directly adhered to the heat sink with silver paste, connected by wire bonding, sealed with liquid epoxy resin, and solder balls were attached to the surface opposite to the metal bonding surface.
(FIG. 3). Similarly, it was connected to the motherboard using solder balls. Table 1 shows the evaluation results of the semiconductor plastic package.

[0043]

[Table 1] Example 1 Comparative example 1 Comparative example 2 Heat resistance after moisture absorption (1) Normal condition No abnormality No abnormality No abnormality No abnormality 72hrs No abnormality No abnormality No abnormality 96hrs No abnormality No abnormality Partial peeling 120hrs No abnormality Partial peeling Partial peeling 144hrs No abnormality Partial peeling Partial peeling 168hrs No abnormality Partial peeling Partial peeling Heat resistance after moisture absorption (2) Normal No abnormality No abnormality No abnormality 24hrs No abnormality Partial peeling Partial peeling 48hrs No abnormality Large peeling Large 72hrs No fault Wire break Wire break 96hrs No break Wire break Wire break 120hrs No break Wire break Wire break 144hrs No break-- 168hrs No break -- Glass transition temperature (℃) 234 234 145 Pressure cook Normal 6 × 10 ¹⁴ 4 × 10 ¹⁴ 6 × 10 ¹⁴ Insulation after car treatment 200hrs 6 × 10 ¹² 5 × 10 ¹² 2 × 10 ⁸ Resistance value (Ω) 500hrs 5 × 10 ¹¹ 3 × 10 ¹¹ <10 ⁸ 700hrs 6 × 10 ¹⁰ 2 × 10 ¹⁰ 1000hrs 2 × 10 ¹⁰ 9 × 10 ⁹ Migration resistance Normal 6 × 10 ¹³ 6 × 10 ¹² 6 × 10 ¹² Functionality 200hrs 4 × 10 ¹¹ 5 × 10 ¹¹ 7 × 10 ⁹ (Ω) 500hrs 3 × 10 ¹¹ 3 × 10 ¹¹ < 10 ⁸ 700hrs 2 × 10 ¹¹ 9 × 10 ¹⁰ 1000hrs 9 × 10 ¹⁰ 8 × 10 ¹⁰ Heat dissipation (° C) 36 56 48

<Measurement method> 1) Heat resistance after moisture absorption (1) JEDEC STANDARD TEST METHOD A113-A LEVEL3: 30 ℃ ・ 60
After the treatment at% RH for a predetermined time, the presence or absence of abnormality in the substrate after three cycles of reflow soldering at 220 ° C. was confirmed by cross-sectional observation and electrical check. 2) Heat resistance after moisture absorption (2) JEDEC STANDARD TEST METHOD A113-A LEVEL2: 85 ℃ ・ 60
After processing at% RH for a predetermined time (Max. 168 hrs.), The presence or absence of abnormality in the substrate after three cycles of reflow soldering at 220 ° C. was confirmed by cross-sectional observation and electrical check. 3) Glass transition temperature Measured by the DAM method.

4) Insulation resistance value after pressure cooker treatment A comb-shaped pattern between terminals (line / space = 70 μm / 70 μm) was prepared, and the prepregs used were arranged on each of them and laminated and formed similarly. Was treated at 121 ° C. and 2 atm for a predetermined time, followed by post-treatment at 25 ° C. and 60% RH for 2 hours, and the insulation resistance between its terminals was measured 60 seconds after applying 500 VDC. 5) Migration resistance Using the test piece of the above 4), the insulation resistance between the terminals was measured by applying 50 VDC at 85 ° C. and 85% RH. 6) Heat dissipation The package was adhered to the same motherboard printed wiring board with solder balls and used continuously for 1000 hours, and then the temperature of the package was measured.

[0046]

According to the present invention, a metal plate having substantially the same size as the printed wiring board is disposed substantially at the center of the printed wiring board in the thickness direction, and at least one metal plate is provided on one side of the printed wiring board. The projection is exposed, the semiconductor chip is fixed thereon, and the semiconductor circuit conductor is connected by wire bonding to the circuit conductor formed on the surface of the printed wiring board around the semiconductor chip. The upper signal propagation circuit conductor is connected to the circuit conductor formed on the opposite surface of the printed wiring board or the conductor pad for connection with the solder ball with a through-hole conductor, and at least one or more through-holes are made of metal. A printed wiring board directly connected to a core, wherein at least a semiconductor chip, wires and bonding pads are sealed with a resin. In the method for manufacturing a double-sided metal foil-clad multilayer board used for a printed wiring board for a plastic package, (1) a metal plate used for a metal core is prepared, an etching resist is formed on the surface of the metal plate, and (2) etching is performed. A convex projection on which a semiconductor chip is mounted is formed on one side. (3) A liquid etching resist is applied again on the entire surface of the metal plate, and the solvent is removed by drying. And irradiate with ultraviolet light. (4) Remove the unexposed resist in the clearance hole
After dissolving and removing with a 1% sodium carbonate solution, etching is performed from both sides to form a clearance hole, and then the etching resist is removed. (5) The prepreg sheet on the side having the metal protrusions is provided with a low-flow or no-flow prepreg sheet, a resin sheet, or a resin layer in which holes slightly larger than the area of the prepreg sheets are formed at the positions of the protrusions. A double-sided board or multilayer board with a circuit formed on one side and a chemically treated surface, with holes slightly larger than the metal projections, placed with the circuit side facing the prepreg side, and clearance on the opposite side A high-flow prepreg sheet, resin sheet, resin-coated copper foil or resin layer having a sufficient amount of resin and resin flow to fill the hole is arranged, and if necessary, a metal foil or a single-sided copper-clad laminate is arranged outside thereof. (6) A double-sided metal foil-clad multilayer board with a metal core having metal projections exposed on one side is formed under heat and pressure, preferably under vacuum. By using a polyfunctional cyanate ester resin composition as a thermosetting resin to be used for a prepreg sheet or a resin layer to be applied, a printed multi-layer wiring board made using the obtained double-sided metal foil-clad multilayer board can be used as a semiconductor. The package manufactured by fixing the chip, wire bonding, and resin sealing does not absorb moisture from the underside of the semiconductor chip, greatly improving the heat resistance after the moisture absorption treatment, that is, the popcorn phenomenon, and also improving the heat dissipation In addition, a semiconductor plastic package having a novel structure which is suitable for mass productivity and improved in economic efficiency was obtained.

[Brief description of the drawings]

FIG. 1 is a manufacturing process of a double-sided metal foil-clad multilayer board of the present invention.

FIG. 2 shows a semiconductor plastic package manufacturing process using the double-sided metal foil-clad multilayer board of the present invention.

FIG. 3 is a cross-sectional view of a single-sided convex inner layer metal plate used in the present invention.

FIG. 4 is a perspective view of a single-sided convex inner layer metal plate used in the present invention.

FIG. 5 shows a semiconductor plastic package manufacturing process of Comparative Example 1.

FIG. 6 shows a semiconductor plastic package manufacturing process of Comparative Example 2.

[Explanation of symbols]

a: metal plate, b: etching resist, c: exposed etching resist, d: single-sided circuit-formed double-sided metal foil-clad laminate, e: low-flow prepreg sheet B, f: metal foil, g: high-flow prepreg sheet C, h: through-hole for front and back circuit conduction, i: semiconductor chip, j: bonding wire, k: heat conductive paste, l: solder ball, m: plating resist, n: sealing resin, o: through-hole for heat radiation

Claims (3)

[Claims] At least one metal plate having substantially the same size as the printed wiring board is disposed at substantially the center in the thickness direction of the printed wiring board, and at least one metal plate is provided on one surface of the printed wiring board. The projection is exposed, and the semiconductor chip is fixed thereon, and the semiconductor chip is connected by wire bonding to the circuit conductor formed on the surface of the printed wiring board around the semiconductor chip. Are connected to the circuit conductor formed on the opposite surface of the printed wiring board or the conductor pad for connection with the solder ball and the plated through-hole conductor, and at least one or more through-holes are provided. Is a printed wiring board directly connected to a metal core, wherein at least a semiconductor chip, a wire, and a bonding pad are resin-sealed. The method of manufacturing a double-sided metal foil-clad multilayer board used for the semiconductor plastic package, (1) providing a metal plate used in the metal core, forming an etching resist on the surface of the metal plate. (2) Etching is performed to form a projection on one side on which a semiconductor chip is mounted. (3) A liquid etching resist is applied again on the entire surface of the metal plate, and the solvent is dried and removed. Then, the surface is covered with a negative film punched out of metal projections, and irradiated with ultraviolet rays. (4) 1% resist in the unexposed clearance hole
After dissolving and removing with a sodium carbonate solution and etching from both sides to form a clearance hole, the etching resist is removed. (5) The prepreg sheet on the side having the metal protrusions is provided with a low-flow or no-flow prepreg sheet, a resin sheet, or a resin layer formed by coating, in which holes slightly larger than the area of the prepreg sheet are formed. A hole slightly larger than the area of the metal protrusion is formed on the top, a circuit is formed on one side, and a double-sided board or a multilayer board whose surface is chemically treated as necessary is arranged, and a clearance hole is sufficiently embedded on the opposite side A high-flow prepreg sheet having a large amount of resin and a resin flow, a resin-coated copper foil, a resin sheet, or an applied resin layer is arranged, and a metal foil or a single-sided metal foil-clad laminate is arranged outside thereof, as necessary. (6) Laminating under heat and pressure, preferably under vacuum, and integrating to form a double-sided metal foil-clad multilayer board with a metal core with metal projections exposed on one side. A method for producing a double-sided metal foil-clad multilayer board with a metal core for a semiconductor plastic package. 2. The method for producing a double-sided metal-foil-clad multilayer board with a metal core according to claim 1, wherein the metal sheet and the circuit metal of the surface layer are an alloy having a copper content of 95% or more or pure copper. 3. The double-sided metal core according to claim 1, wherein the insulating resin composition is a thermosetting resin composition containing a polyfunctional cyanate ester and the cyanate ester prepolymer as essential components. A method for producing a metal foil-clad multilayer board.