JPH11330303A - Semiconductor plastic package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a semiconductor plastic package to be improved in adhesion to a surface metal foil, enhanced in heat dissipating properties, and restrained from absorbing moisture through the underside of a chip, by a method wherein at least a viahole is joined to an inner metal plate through a rear surface, and truncated conical metal projections provided to the metal plate are connected to the rear side of a metal foil which fixes a semiconductor chip. SOLUTION: A viahole is bored in a board so as to reach to an inner metal board, the board is subjected to a de-smearing treatment and plated with metal, and a circuit is formed on each side of the board. A semiconductor chip is fixed on the upper surface of a metal-cored printed wiring board provided with through-holes C, truncated conical metal projections are provided to a metal board b possessed of an iron core at positions where the semiconductor chip is fixed through a well-known etching method. Thermally conductive adhesive agent, is attached to the inner metal truncated conical metal projections of the printed wiring board under a metal foil d where the semiconductor chip is amounted if necessary, and the printed wiring board is bonded to the metal foil d. By this setup, a semiconductor plastic package enhanced in adhesion to a surface metal foil and reliability 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 novel semiconductor plastic package in which at least one semiconductor chip is mounted on a small printed wiring board, and more particularly to a relatively small package such as a microprocessor, a microcontroller, an ASIC, and a graphic. Suitable for high wattage, multi-terminal, high-density semiconductor plastic packages. The semiconductor plastic package of the present invention 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 semiconductor chip is fixed on a plastic printed wiring board such as a plastic ball grid array (P-BGA) or a plastic land grid array (P-LGA) as a semiconductor plastic package. Bonded to the conductor circuit formed on the upper surface of the printed wiring 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 plated the front and back circuit conductors 2. Description of the Related Art A semiconductor plastic package having a structure in which a semiconductor chip is sealed with a resin by connecting through a formed through hole is known. In the known structure, a plated heat diffusion through hole is formed from the upper metal foil for fixing the semiconductor chip to the lower surface in order to diffuse the heat generated from the semiconductor to the motherboard printed wiring board. Through this through-hole, moisture is absorbed by the resin adhesive containing silver powder used to fix the semiconductor, causing danger of interlayer blisters due to heating during mounting on the motherboard and heating when removing semiconductor components from the motherboard. This 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 that the amount of heat generated increases more and more, and heat dissipation is becoming insufficient only with through holes directly below the semiconductor chip for heat dissipation. .

[0003]

SUMMARY OF THE INVENTION The present invention provides a semiconductor plastic package which solves the above problems.

[0004]

According to the present invention, a metal plate having substantially the same size as a printed wiring board is disposed at a substantially central portion in a thickness direction of the printed wiring board.
At least one semiconductor chip is fixed with a heat conductive adhesive, the metal plate and the signal transmission circuit conductor on the surface are insulated with a thermosetting resin composition, and the semiconductor chip is formed on the printed wiring board surface. Connect with conductor by wire bonding,
At least a circuit conductor on the printed wiring board on the front surface and a circuit conductor formed on the opposite surface of the printed wiring board or a circuit conductor pad formed for connection with a solder ball to the outside of the package are formed on a metal plate. In a semiconductor plastic package with a structure in which the semiconductor chip, wires, and bonding pads are resin-sealed, at least one via hole is formed from the back surface of the inner metal layer A metal foil which is formed so as to be directly bonded to a board, turns the wall of the via hole into a heat conductor, and directly fixes a plurality of truncated conical metal projections of a metal plate constituting a part of the printed wiring board to a semiconductor chip; A semiconductor plastic package having a novel structure, characterized in that the projection is bonded to the metal foil with a heat conductive adhesive as necessary. To provide a cage. The semiconductor plastic package of the present invention, having the above structure, has good adhesion to the surface layer metal foil, excellent heat dissipation,
There is no moisture absorption from the lower surface of the semiconductor chip, and the heat resistance after moisture absorption, that is, the popcorn phenomenon is greatly improved, and the electrical insulation and the migration resistance after the pressure cooker are excellent, and it is also suitable for mass production. It has the characteristic that economic efficiency is improved.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The plastic package of the present invention has a metal protrusion having a truncated conical surface at substantially the center in the thickness direction of a printed wiring board, and a heat conductive adhesive is adhered on the truncated conical shape if necessary. A metal plate with good heat dissipation is placed, and the plated through holes for circuit conductor conduction on the front and back are the clearance hole diameters drilled in the metal plate,
Alternatively, a hole having a diameter smaller than the width of the slit hole is formed at substantially the center of the embedded resin, thereby maintaining the insulation with the metal plate.

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. According to the present invention, first, a plurality of truncated cone-shaped protrusions are formed at positions where a semiconductor chip is fixed by a known method such as etching a metal plate serving as a metal core. Also, a clearance hole or a slit hole larger than the diameter of the through hole is formed at a position where the through hole is to be formed by a known etching method, a punching method, , Formed on the metal core by laser or the like.

The surface of the metal plate on which the truncated conical protrusions and the clearance holes or slit holes are formed is subjected to a surface treatment for improving adhesion and electrical insulation such as oxidation treatment, formation of fine irregularities, and formation of a film by a known method. Apply as needed. The surface treatment is performed to form a plurality of truncated cone-shaped protrusions, and a heat conductive adhesive is adhered thereon as necessary. The entire surface is formed of a thermosetting resin composition at such a height that the metal protrusions are slightly exposed. The formation of the insulating portion using the thermosetting resin composition is performed using a prepreg, a resin sheet, a resin-coated metal foil, or the like, which is obtained by impregnating the base material with the thermosetting resin composition in a semi-cured state and drying it. The heat generated from the semiconductor chip is conducted from this mounting portion, passes through the truncated conical protrusion of the inner metal plate, is transmitted to the metal plate, and is joined with the solder ball through a via hole on the back surface directly joined to the metal plate. Diffusion on motherboard printed wiring board. The back side is prepreg, metal foil with resin,
A resin sheet, a coated resin layer, and the like are placed, and a metal foil is disposed as necessary, and laminated and integrated under heating and pressure, preferably under vacuum. On the front and back layers, a single-sided metal foil-clad laminate, a single-sided circuit-formed double-sided metal foil-clad laminate, or a single-sided circuit-formed multilayer plate is arranged, and heated and pressed, preferably under vacuum, may be laminated and integrated. it can.

[0008] The side surface of the metal plate may be any of a shape embedded with a thermosetting resin composition and an exposed shape. It is preferable that the surface is not exposed.

In addition, a through-hole printed wiring board by the subtractive method is formed by laminating a metal foil or the like slightly larger than the printed wiring board on the outermost layers on the front and back sides during lamination molding, and laminating under heat and pressure. A metal-foil-clad laminate having a metal core covered on both sides with a metal foil for forming an outer layer circuit is formed.

In the case of laminating and molding without using a metal foil for the front and back layers, a circuit is formed by a known additive method to produce a printed wiring board.

[0011] In a plate prepared by the subtractive method or the semi-additive method, a through hole for conducting a circuit between the front and back is formed in a portion other than a portion for fixing a semiconductor by a known method such as drilling, laser or plasma. Drill holes.

The through hole for conducting the front and back circuits is formed substantially at the center of the metal plate clearance hole or slit hole in which the resin is embedded so as not to contact the metal plate. If necessary, a desmear treatment is performed, and then a metal layer is formed inside the through hole by electroless plating or electrolytic plating to form a plated through hole. In the full additive method, a circuit, a solder ball pad, and the like are simultaneously formed on the front and back surfaces.

In the semi-additive method, the through holes are plated and the front and back surfaces are also plated at the same time.
Circuits are formed above and below by a known method.

The via hole on the back surface is formed by a generally known method such as a carbon dioxide laser or a mechanical drill. Desmearing is performed if necessary, and metal plating is performed. Alternatively, a heat conductive adhesive is filled.

After forming the front and back circuits, a noble metal plating is formed on at least the surface of the wire bonding pad 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. Or, after plating, if necessary, a known thermosetting resin composition, or a photoselective thermosetting resin composition, at least on the semiconductor chip mounting portion, the bonding pad portion, and the surface other than the solder ball bonding pad portion on the opposite surface. Form a film.

On the printed wiring board, a heat conductive adhesive is adhered on the inner layer frustoconical projection under the metal foil on which the semiconductor chip is mounted, if necessary, and is bonded to the metal foil during lamination molding. Thereby, the adhesiveness with the surface metal foil is improved, and a material having excellent reliability is obtained. On this metal foil, a semiconductor chip is fixed using a heat conductive adhesive,
Further, the semiconductor chip and the bonding pad of the printed wiring board circuit are connected by a wire bonding method, and at least the semiconductor chip, the bonding wire, and the bonding pad are sealed with a known sealing resin.

A solder ball is connected to the solder ball connecting conductor pad on the opposite side of the semiconductor chip to form a P-BGA, the solder ball is superimposed on a circuit on a motherboard printed wiring board, and the ball is melted by heat to print the motherboard. When connecting to the wiring board or making a P-LGA without attaching solder balls to the package and mounting it on the motherboard printed wiring board, the solder ball connection conductor pad and P-LGA formed on the motherboard printed wiring board surface The solder balls are connected to the solder ball conductor pads by heating and melting the solder balls.

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 500 μm is suitable. Specifically, pure copper, oxygen-free copper, and others,
An alloy of 95% by weight or more of copper with Fe, Sn, P, Cr, Zr, Zn, or the like is preferably used. Further, a metal plate or the like in which the surface of the alloy is plated with copper may be used.

The height of the metal-cone-shaped protrusion having the heat conductive adhesive adhered thereto is not particularly limited, but is preferably 50 to 150 μm. Also, the thickness of the insulating layer of the prepreg, resin sheet, resin-coated metal foil, coating resin, etc. is slightly lower than the height of the metal truncated conical projection, preferably 5 to 15 μm lower,
After lamination molding, it is connected to the surface metal foil. The size of the truncated cone is not particularly limited, but generally, the diameter of the bottom is 0.1 ■ 5 m.
m, the diameter of the upper part is 0 to 1 mm.

Known materials can be used as the heat conductive adhesive. Specific examples include a silver paste, a copper paste, a solder paste, and a lead-free solder such as a tin-silver-copper-based solder. The range of the protruding portion of the metal truncated cone is set to be smaller than the area of the semiconductor chip, generally within 5 to 20 mm square, and to be present below the fixing portion of the semiconductor chip.

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 ester resin, a polyfunctional maleimide-cyanate ester resin, a polyfunctional maleimide resin, and an unsaturated group-containing polyphenylene ether resin. 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 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-cyanatophenyl)
Phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting novolak with cyanogen halide.

In addition to these, Japanese Patent Publication No. 41-1928 / 43-1846
8, 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. 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. The prepolymer comprises the above-described polyfunctional cyanate ester monomer, for example, a mineral acid,
It can be obtained by polymerization using an acid such as a Lewis acid; a base such as a tertiary amine such as sodium alcoholate; a salt such as sodium carbonate as a catalyst. 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, generally known epoxy resins 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 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, and 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 And high molecular weight prepolymers or oligomers such as polyphenylene sulfide; and polyurethane. In addition, other known inorganic or organic fillers, dyes, pigments, thickeners, lubricants, defoamers,
Various additives such as a dispersant, a leveling agent, 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.

As the reinforcing base material of the prepreg, generally known inorganic or organic woven or nonwoven fabrics are 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 outermost metal foil, generally known ones can be used. Preferably, a copper foil, a nickel foil or the like having a thickness of 3 to 180 μm is used.

The diameter of the clearance hole or the width of the slit formed in the metal plate is formed slightly larger than the diameter of the through hole for front and back conduction. Specifically, it is preferable that a distance of 50 μm or more between the through hole wall and the metal plate clearance hole or slit hole wall is insulated by the thermosetting resin composition. The diameter of the through-hole for front / back conduction is not particularly limited, but is preferably 50 to 300 µm.

When preparing a prepreg for a printed wiring board of the present invention, a substrate is impregnated with a thermosetting resin composition and dried to obtain a semi-cured laminated material. Also, a resin sheet in a semi-cured state without using a base material 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. In the case of no flow, when the laminate is molded by heating and pressing, the flow of the resin is 100 μm or less, preferably 50 μm.
m or less. At this time, it is important that the metal plate and the metal foil adhere to each other and no void is generated. The temperature at which the prepreg is made is generally between 100 and 180 ° C. The time is 5 to 60 minutes, and is appropriately selected depending on the desired flow rate.

The method for producing the semiconductor plastic package containing the metal core of the present invention is not particularly limited. For example, the following method shown in FIGS. 1 and 2 is used. (1) The entire surface of the metal plate serving as the inner layer is coated with a liquid etching resist, and the solvent is removed by heating. Then, a negative film is formed so that the resist corresponding to the portion where the semiconductor chip is fixed remains in a small circle, After UV irradiation, 1
A portion other than the circular exposed portion and a clearance hole portion on the back surface are dissolved and removed with a sodium hydroxide solution. The metal plate is melted to a predetermined thickness by etching to form frustum-shaped projections and clearance holes on the surface, then the etching resist is removed, and the entire surface of the metal plate is subjected to chemical surface treatment (FIG. 1 (1)). (2) Lead-free solder a is attached on the truncated cone (FIG. 1 (2)), and (3) a thermosetting resin composition is applied to a metal foil on the surface,
A metal foil with resin in a semi-cured state obtained by drying is placed. In this case, the resin layer is formed such that the tips of the truncated cone-shaped protrusions remain slightly thinner than the thickness of the metal foil. A prepreg, resin sheet, metal foil with resin, or coated resin layer is placed on the back side, and if necessary, metal foil, single-sided metal foil-clad laminate, single-sided circuit-formed double-sided metal foil-clad laminate, or single-sided circuit-formed multilayer board (3), and (4) after laminating under heat, pressure and vacuum (FIG. 2)
(4)), (5) A through hole is drilled at a predetermined position so as not to contact the inner metal foil (Fig. 2 (5)). (6) A via hole is formed on the back side with a mechanical drill, laser, etc. After plating up to the inner layer metal plate and performing desmear treatment, metal plating is performed, and circuits are formed on the upper and lower sides by a known method. After covering the parts other than the semiconductor chip mounting part on the front surface, the bonding pad part, and the solder ball pad part on the back surface with plating resist, apply precious metal plating, and the inner metal plate becomes a truncated conical projection and metal foil with a heat conductive adhesive The semiconductor chip is bonded with lead-free solder on the semiconductor chip mounting portion that is in contact with the semiconductor chip, wire bonding is performed, and then resin sealing is performed, and if necessary, solder balls are bonded (FIG. 2).
(6)).

[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, Yuka Shell Epoxy Co., Ltd.) and cresol novolac type epoxy resin (trade name: ESCN-220F, Sumitomo Chemical Co., Ltd.) 60
0 parts were added and uniformly dissolved and mixed. Further, 0.4 part of zinc octylate is added as a catalyst, dissolved and mixed, and an inorganic filler (trade name: calcined talc BST-200, Nippon Talc Co., Ltd.) is added.
Was added and mixed uniformly with stirring to obtain Varnish A.
This varnish is applied to a glass woven fabric having a thickness of 100 μm, dried, and gelled (at 170 ° C.) for 50 seconds, 170 ° C., 20 kgf / cm ² , 5
A prepreg B in a semi-cured state having an insulating layer thickness of 113 μm was prepared so that the resin flow per minute was 10 mm. Varnish A was applied to the treated surface of the 12 μm electrolytic copper foil and dried to obtain resin-coated copper foil C having a gelling time of 65 seconds and an insulating layer thickness of 114 μm.

On the other hand, a 200 μm-thick Cu:
Prepare an alloy plate of 99.9%, Fe: 0.07%, P: 0.03%, apply 25μm of liquid etching resist on the top and bottom and dry it. On the surface, within the center 13mm square of 50mm square package, 2mm width A negative film created so that a circular resist with a diameter of 300 μm remains, and a negative film formed so that the resist in the clearance hole is removed on the back surface.
Dissolve and remove with 1% sodium carbonate solution. Etch from both sides. Height 117μm, bottom diameter 520μm, top 25
25 frustoconical projections with a hole diameter of 0.6
A clearance hole of mm was opened (FIG. 1 (1)). Lead-free solder (tin / silver / copper = 96 / 3.5 /
0.5%) with a thickness of 5 μm (FIG. 1 (2)), the resin body and the copper foil C are placed on the upper surface, a prepreg B is placed on the lower surface, and a 12 μm electrolytic copper foil is placed on the outside of the prepreg B (FIG. 1 (2)). 1
(3)), laminated and molded under a vacuum of 230 ° C., 20 kgf / cm ² and 30 mmHg or less for 2 hours, and integrated (FIG. 2 (4)). In the clearance hole, a through hole having a hole diameter of 0.25 mm was drilled at the center so as not to contact the metal core of the clearance hole (FIG. 2 (5)). Also, on the back,
In the center 13 mm square, a hole with a hole diameter of 100 μm is opened in copper foil by etching method, a via hole is made to the inner metal plate by irradiating carbon dioxide laser, and after desmear treatment, copper plating is performed by electroless and electrolytic plating. Then, a copper plating layer of 17 μm was formed in the hole. Attaching an etching resist on the front and back, overlaying a positive film, exposing and developing, forming a front and back circuit, forming a plating resist other than the semiconductor chip mounting part, bonding pad part and ball pad part, applying nickel and gold plating To complete the printed wiring board. After bonding and fixing a 13 mm square semiconductor chip with silver paste to the portion where the truncated conical protrusion on the surface is connected to the copper foil, wire bonding is performed, and then using a silica-containing epoxy sealing liquid resin, the semiconductor chip portion, The wire portion and the bonding pad portion were sealed with resin, and solder balls were joined to form a semiconductor plastic package (FIG. 2 (6)). This semiconductor plastic package was melt-bonded with a solder ball to an epoxy resin mother board printed wiring board. Table 1 shows the evaluation results.

Example 2 A printed wiring board was prepared in the same manner as in Example 1 except that lead-free solder was not used, and a semiconductor plastic package was prepared. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 1 Two prepregs B of Example 1 were used, and 12 μm electrolytic copper foils were arranged on the upper and lower sides (FIG. 3 (1)), at 200 ° C. and 20 kgf / cm.
^2. Lamination molding was performed for 2 hours under a vacuum of 30 mmHg or less to obtain a double-sided copper-clad laminate (FIG. 3 (2)). 0.25m hole diameter in place
An mφ through-hole was drilled and copper plated after desmearing. Circuits were formed on and under the plate by a known method, and were covered with a plating resist and then plated with nickel and gold (FIG. 3 (3)). This has a through hole for heat dissipation at the place where the semiconductor chip is mounted, the semiconductor chip is bonded with silver paste on this, and after wire bonding, it is sealed with a resin for epoxy sealing in the same manner as in Example 1. And solder balls were joined (Fig. 3
(4))). Similarly joined to the motherboard. Table 1 shows the evaluation results.

Comparative Example 2 700 parts of an epoxy resin (trade name: Epikote 5045), 300 parts of an epoxy resin (trade name: ESCN220F), 35 parts of dicyandiamide, and 1 part of 2-ethyl-4-methylimidazole were prepared by mixing methyl ethyl ketone and dimethylformamide. Uniformly dissolved in a mixed solvent, impregnated in a glass woven cloth with a thickness of 100 μm and dried, gelling time (at 170 ° C) for 10 seconds, resin flow
98μm no-flow prepreg (prepreg D), gelling time 150 seconds, resin flow 18mm high-flow prepreg
(Prepreg E) was prepared. Two prepregs E were laminated and molded at 190 ° C., 20 kgf / cm ² , and a vacuum of 30 mmHg or less for 2 hours to prepare a double-sided copper-clad laminate (FIG. 4A).
After that, a printed wiring board was prepared in the same manner as in Comparative Example 1, the semiconductor chip mounting portion was cut out with a counterbore machine, and a copper plate having a thickness of 200 μm was punched out from the no-flow prepreg D on the rear surface, Adhesion was similarly performed under heating and pressure to produce a printed wiring board with a heat sink (FIG. 4).
(2)). This slightly warped. A semiconductor chip was directly adhered to the heat sink with silver paste, connected by wire bonding, and sealed with liquid epoxy resin (FIG. 4).
(3)). Similarly, it was joined to a motherboard printed wiring board. Table 1 shows the evaluation results.

Table 1 Item Example Comparison Example 1 2 1 2 Heat resistance after moisture absorption ¹⁾ Normal state No abnormality No abnormality No abnormality No abnormality 24hrs. No abnormality No abnormality No abnormality No abnormality 48hrs. No abnormality No abnormality No abnormalities No abnormalities 72hrs. No abnormalities No abnormalities No abnormalities No abnormalities No abnormalities 96hrs. No abnormalities No abnormalities No abnormalities Partial peeling 120hrs. No abnormalities No abnormalities Partial peeling partial peeling 144hrs. No abnormalities No abnormalities Partial peeling Partial peeling 168hrs No abnormalities No abnormalities Partial peeling Partial peeling Heat resistance after moisture absorption ²⁾ Normal conditions No abnormalities No abnormalities No abnormalities No abnormalities 24 hrs. No abnormalities No abnormalities Partial peeling Partial peeling 48 hrs. No abnormalities No abnormalities Large peeling Large peeling 72hrs. No abnormalities No abnormalities Wire breaks Wires 96hrs. No abnormalities No abnormalities Wire breaks Wires 120hrs. No abnormalities No abnormalities Wire breaks Wires 144hrs. No abnormalities No abnormalities − -168hrs. No abnormality No abnormality--Glass transition temperature (° C) 237 237 234 160

[0040] Table 1 (Continued) Item implementation example comparisons Example 1 2 1 2 pressure cooker treatment after the insulation resistance (Omega) normal state ^{4 × 10 14 5 × 10 14} 6 × 10 14 5 × 1014 200hrs. 6 × 10 ¹² 5 × 10 ¹² 5 × 10 ¹² 2 × 10 ⁸ 500 hrs. 6 × 10 ¹¹ 3 × 10 ¹¹ 3 × 10 ¹¹ <10 ⁸ 700 hrs. 5 × 10 ¹⁰ 6 × 10 ¹⁰ 2 × 10 ¹⁰ −1000 hrs. 2 × 10 ¹⁰ 1 × 10 ¹⁰ 1 × 10 ₁₀ − Migration resistance (Ω) Normal 6 × 10 ¹³ 6 × 10 ¹³ 4 × 10 ¹³ 6 × 10 ¹³ 200 hrs. 5 × 10 ¹¹ 4 × 10 ¹¹ 4 × 10 ¹¹ 3 × 10 ⁹ 500 hrs. 4 × 10 ¹¹ 4 × 10 ¹¹ 4 × 10 ¹¹ <10 ⁸ 700 hrs. 1 × 10 ¹¹ 2 × 10 ¹¹ 1 × 10 ¹¹ −1000 hrs. 9 × 10 ¹⁰ 1 × 10 ¹⁰ 8 × 10 ¹⁰ -Heat dissipation (° C) 35 36 56 48 Adhesion to surface copper foil Very good Good--

<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 DMA method. 4) Insulation resistance value after pressure cooker treatment A comb-shaped pattern was formed between terminals (rainn / supe-su = 70/70 μm), and a prepreg or resin layer used respectively was formed thereon, and was cured by heating. The sample was treated at 121 ° C. and 2 atm for a predetermined period of time, followed by post-treatment at 25 ° C. and 60% RH for 2 hours. After applying 500 VDC for 60 seconds, the insulation resistance between the terminals was measured. 5) Migration resistance The test piece of the above 4) was applied at 85 ° C. and 85% RH at 50 VDC, and the insulation resistance between the terminals was measured. 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. 7) Adhesion to Surface Metal Foil All cross sections of the truncated conical protrusion were observed.

[0042]

According to the present invention, a metal plate having substantially the same size as the printed wiring board is arranged at substantially 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 semiconductor chip is fixed with a heat conductive adhesive, the metal plate and the surface circuit are insulated with a thermosetting resin composition such as a polyfunctional cyanate ester, and the circuit formed on the surface of the printed wiring board. A conductor and a semiconductor chip are connected by wire bonding, at least a signal propagation circuit conductor on the printed wiring board on the surface, a circuit conductor formed on the opposite surface of the printed wiring board or a conductive pad for connection with the solder ball. Are connected by a through-hole conductor insulated with a metal plate and a resin composition, and at least a semiconductor chip portion, a wire portion, and a bonding pad portion are resin-sealed. In Mark Package, at least
One via hole is directly joined to the inner layer metal plate from the back surface, and the hole wall of the via hole is made a heat conductor, and a plurality of truncated conical metal projections of the metal plate constituting a part of the printed wiring board are formed. A plurality of truncated cone-shaped metal projections of a metal core are brought into contact with the back side of the metal foil for directly fixing the semiconductor chip, and if necessary, the metal projections are bonded and fixed to the metal foil with a heat conductive adhesive. In addition, there is provided a semiconductor plastic package having a novel structure having a configuration in which a semiconductor chip is fixed with a heat conductive adhesive. According to the present invention, the heat generated from the semiconductor chip passes through this metal plate frustoconical projection, conducts to the inner metal plate, escapes to the solder ball through the via hole on the back surface directly connected to the metal plate, Excellent heat dissipation, no moisture absorption from the underside of the semiconductor chip, greatly improved heat resistance after moisture absorption, that is, popcorn phenomenon, and also suitable for mass production Thus, a semiconductor plastic package having a novel structure with improved economy is provided.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of a semiconductor plastic package according to a first embodiment.

FIG. 2 is a manufacturing process diagram of the semiconductor plastic package of the first embodiment.

FIG. 3 is a manufacturing process diagram of the semiconductor plastic package of Comparative Example 1.

FIG. 4 is a manufacturing process diagram of a semiconductor plastic package of Comparative Example 2.

[Explanation of symbols]

 a Lead-free solder b Metal plate c Clearance hole d Metal foil e Resin layer f Prepreg B g Front and back circuit conduction through hole h Sealing resin i Semiconductor chip j Silver paste k Bonding wire l Solder ball m Plating resist n Prepreg C o Heat radiation For through hole

Claims (3)

[Claims] 1. A metal plate having a size substantially the same as that of a printed wiring board is disposed at a substantially central portion in a thickness direction of the printed wiring board, and at least one semiconductor chip is thermally conductive on one surface of the printed wiring board. It is fixed with an adhesive, the metal plate and the signal transmission circuit conductor on the surface are insulated with a thermosetting resin composition, and the semiconductor chip is connected to the circuit conductor formed on the surface of the printed wiring board by wire bonding. The circuit conductor on the printed wiring board on the front surface and the circuit conductor formed on the opposite surface of the printed wiring board or the circuit conductor pad formed for connection with the outside of the package by a solder ball are connected to a metal plate and a resin. Connected with a through-hole conductor insulated with the composition, and at least a semiconductor plastic package having a structure in which the semiconductor chip, wires, and bonding pads are resin-sealed. At least one via hole is formed so as to be directly joined to the inner metal plate from the back surface, the inner wall of the via hole is made into a heat conductor, and a plurality of cones of the metal plate forming a part of the printed wiring board are formed. A semiconductor plastic package, wherein a trapezoidal metal projection is in contact with the back side of a metal foil to which a semiconductor chip is directly fixed, and the projection is bonded to the metal foil with a heat conductive adhesive if necessary. 2. The semiconductor plastic package according to claim 1, wherein the metal plate is made of a copper alloy containing 95% by weight or more of copper or pure copper. 3. The semiconductor plastic package 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.