JP2000323836A - Manufacture of metal core for printed wiring board having metal core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal core for a printed wiring board having excellent heat radiation, heat resistance after humid adsorption and the like with favorable workability at low cost in a printed wiring board having a metal core. SOLUTION: A clearance hole or slit is formed at a site other than where a semiconductor chip is mounted in a metal plate used to constitute a metal core. Subsequently, a metal core is formed by machining the semiconductor chip mounting site so that a plurality of protrusions in a truncated cone shape slightly taller than the metal core are provided on front and rear surfaces. Furthermore, a polyfunctional cyanate ester resin composite is used as a thermosetting resin composite. There can be provided a metal core for a printed wiring board for use in a semiconductor plastic package in a structure which is excellent in connection between the inner-layer metal core and the outer metal foil layer and heat radiation and suitable for mass production. Furthermore, there is provided a metal core with which a package excellent in properties such as electric insulation, anti-migration and the like after pressure cooking can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal core of a novel semiconductor plastic package having a metal core, wherein at least one semiconductor chip is mounted on a small printed wiring board. The resulting printed wiring board is suitable for use in relatively high wattage, multi-terminal, high-density semiconductor plastic packages such as microprocessors, microcontrollers, ASICs, and graphics. The present semiconductor plastic package 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, as a semiconductor plastic package, a semiconductor chip such as a plastic ball grid array (P-BGA) or a plastic land grid array (P-LGA) is fixed on the upper surface of a plastic printed wiring board. It is connected to the conductor circuit formed on the upper surface of the printed wiring board by wire bonding, and the lower surface of the printed wiring board is formed with conductor pads for connection with the motherboard printed wiring board using solder balls, and the front and back circuit conductors are plated 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 heat diffusion through hole, moisture is absorbed by the resin adhesive containing silver powder used for fixing the semiconductor, and by heating when mounting on the motherboard,
There is a risk of causing interlayer blisters due to heating when the semiconductor component is removed from the motherboard, which is called a 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.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printed wiring board for a semiconductor plastic package containing a metal core in which the above problems are improved.

[0004]

That is, according to the present invention, a metal plate having substantially the same size as a printed wiring board is arranged in a part of the printed wiring board in a thickness direction, and at least one metal plate is provided on one surface of the printed wiring board. The semiconductor chip is fixed, the metal plate and the signal propagation circuit conductor on the surface of the printed wiring board are insulated with a thermosetting resin composition, and the circuit conductor and the semiconductor chip are bonded by wire bonding or flip chip bonding. Connecting, at least a signal propagation circuit conductor on the surface of the printed wiring board, and a circuit conductor formed on the opposite surface of the printed wiring board or a circuit conductor pad formed for connecting the package to the outside with solder balls. The board is connected with a through-hole conductor insulated with a thermosetting resin composition composition, and in the case of wire bonding connection, at least a semiconductor chip, In a method of manufacturing a metal core for a printed wiring board used for a semiconductor plastic package having a structure in which a conductive chip, a wire, and a bonding pad are sealed with a resin, first, a clearance is formed on a metal plate serving as the metal core except for a portion where the semiconductor chip is mounted. Drill a hole or a slit hole, then process the semiconductor chip mounting location into a different shape using a mold, etc., and form a plurality of truncated cone-shaped metal protrusions on the front and back,
Provided is a method for manufacturing a metal core for a printed wiring board, wherein a metal core is formed by applying pressure from both sides so as to be slightly higher than a metal plate. This metal core is chemically treated, and a prepreg, a resin sheet, or a coating resin layer having a truncated cone-shaped metal projection area for mounting a semiconductor chip is formed on both sides thereof, and an insulating layer is formed slightly lower than the metal projection after lamination molding. Arranged so that it is placed, put a metal foil on the outside, heat, pressurized, preferably laminated and integrated under vacuum, integrated,
Create double-sided metal foil clad laminate with metal core. Drill through holes for through holes, apply desmear treatment if necessary, apply metal plating, leave the part on the metal foil on the surface of the semiconductor chip mounting part, and form a circuit on the other, at least the semiconductor chip on the surface Except for the mounting metal foil, the bonding pad, and the ball pad on the back surface, the coated wiring is covered with a plating resist, and nickel plating and gold plating are performed to obtain a printed wiring board for a semiconductor plastic package with a metal core. The obtained semiconductor plastic package is excellent in thermal conductivity, does not absorb moisture from the lower surface of the semiconductor chip, and greatly improves heat resistance after absorbing moisture, that is, the popcorn phenomenon. Furthermore, by using a polyfunctional cyanate resin composition as a thermosetting resin, it is excellent in electrical insulation after pressure cooker, migration resistance, and the like,
In addition, it is suitable for mass production and has improved economy.
A semiconductor plastic package having a novel structure can be obtained.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A semiconductor plastic package manufactured by using a copper-clad board manufactured according to the present invention has a metal plate having substantially the same size as a printed wiring board arranged in a part of the thickness direction. At least one or more semiconductor chips are fixed to one surface of the wiring board, and the metal plate and the signal propagation circuit conductor on the surface of the printed wiring board are insulated with a thermosetting resin composition. Are connected by wire bonding or flip chip bonding, and at least the circuit conductor on the surface of the printed wiring board,
A circuit conductor formed on the opposite surface of the printed wiring board or a circuit conductor pad formed for connecting the package to the outside with solder balls, is connected with a metal plate and a through-hole conductor insulated with a resin composition, In the case of wire bonding connection, a semiconductor plastic package having a structure in which at least a semiconductor chip, a wire, and a bonding pad are resin-sealed. In the metal core of the present invention, first, a clearance hole or a slit hole is formed in a metal plate other than the portion where the semiconductor chip is mounted, and then the portion where the semiconductor chip formed substantially in the center of the package is mounted is formed of gold. A plurality of truncated cone-shaped protrusions are formed by applying pressure to the front and back surfaces by molding or the like so that the height thereof is slightly higher than that of the metal plate, thereby forming a metal core. The surface of this metal core is chemically treated, and a semi-cured prepreg, a resin sheet, or a coating resin layer in which the protrusions are cut off slightly larger than the area having the metal protrusions is arranged, and a metal foil is placed outside the prepreg, Heating, under pressure, preferably after laminating and integrating under vacuum, mechanical drill, through holes for through holes with laser, etc., so as not to contact the inner metal plate,
If necessary, metal plating is performed after the desmear treatment to form circuits on the front and back. In the case of the wire bonding connection, at least parts other than the semiconductor chip, the wire bonding pads on the front surface, and the ball pads on the back surface are covered with a plating resist, and nickel plating and gold plating are performed to produce a printed wiring board. A semiconductor chip is fixed on a metal foil in contact with a truncated conical metal protrusion on the surface, and the semiconductor chip is connected to surrounding circuit conductors by wire bonding or flip chip bonding. In the case of wire bonding, at least a semiconductor chip, bonding wires, and bonding pads are sealed with a resin. The solder ball pad connected to the precious metal-plated metal foil on the frustoconical projection on the back side is made by melting the solder ball and joining it to the motherboard printed wiring board, and the front and back circuit conductors and plated through for conduction The holes have a structure insulated by a thermosetting resin composition.

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 dissipation through hole immediately below, similarly to a conventional P-BGA package. Heat must be dissipated, and the popcorn phenomenon cannot be improved. In the present invention, in a metal flat plate serving as a metal core, in addition to the place where the semiconductor chip is mounted, a clearance hole or a slit hole is formed by a known method, and then the central semiconductor chip mounting area is pressurized by machining. A plurality of truncated cone-shaped metal projections are formed on both sides. The height of the metal projection is slightly higher than the height of the metal plate, preferably 50 to 150 μm.
Is formed to have a height of On both sides of this metal core, a semi-cured prepreg, a resin sheet or a coating resin layer with a hole slightly larger than the area of the metal protrusion is arranged so as to be slightly lower than the height of the protrusion after lamination molding, and , A metal foil is placed and laminated under heat, pressure and preferably under vacuum to produce a double-sided metal foil clad board with an inner metal core. At the clearance hole or slit hole, make a through hole for front and back circuit conduction with a mechanical drill or laser etc. so that it does not contact the metal core of the inner layer, perform desmear treatment if necessary, apply metal plating, To form a circuit. After that, at least parts other than the semiconductor chip mounting part, the bonding pad part, and the solder ball pad part on the back surface are covered with a plating resist, and nickel plating and gold plating are performed to obtain a printed wiring board.

The method of forming the metal core is not particularly limited. For example, first, a clearance hole or a slit hole is punched, drilled, laser, or the like, except for a region where a truncated cone-shaped metal projection is formed on a flat metal plate. Etching or the like is performed, and then pressure is applied from above and below with a mold or the like to only the position where the truncated conical projection of the metal plate is formed, and the truncated conical projection is formed by mechanical processing. In this case, the size of the truncated cone-shaped projection is not particularly limited, but preferably, the diameter of the upper portion of the trapezoid is 50 to 500 μm, and the diameter of the lower portion is 100 μm to 1 mm. The height of the metal projection is slightly higher than the height of the original metal plate, preferably 50 to 150 μm.

The surface of the metal plate on which the truncated cone-shaped 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. A heat conductive adhesive or solder may be adhered to the truncated conical projection. In the surface-treated front and back frusto-conical protrusions, the prepreg, resin sheet, or coating resin layer slightly larger than the area of the shape is slightly lower than the height of the truncated conical protrusions after lamination molding. Arranged in such a way, put a metal foil on the outside, heat, pressurize, preferably laminated under vacuum, fill the clearance hole or slit hole with thermosetting resin, and put the tip of the truncated cone-shaped metal protrusion on the surface Or a metal foil with a metal core to form a double-sided metal foil clad board.

In the obtained double-sided metal foil-clad board, a through hole is formed at a place where a clearance hole or a slit hole is formed so as not to come into contact with a metal core by a known method such as a mechanical drill or a laser. Plate. It is preferable that a ball pad be formed on the back surface so as not to be in contact with the metal protrusion. In this case, the ball pad is connected to the metal foil on the metal protrusion by a circuit so that a circuit is formed by a generally known method. In this case, at least the surface layer other than the semiconductor chip mounting portion, the bonding pad portion, and the solder ball pad portion on the back surface are covered with a plating resist, and nickel and gold plating is performed to produce a printed wiring board. Thereafter, in the wire bonding, a semiconductor chip is bonded and fixed to the semiconductor chip mounting portion on the surface with a thermally conductive adhesive, wire-bonded, and resin-sealed to obtain a semiconductor plastic package. In the case of flip chip bonding, the heat dissipation bump is connected to the metal foil surface where the central frustoconical projection is in contact,
The signal propagation bumps are connected to other signal propagation circuits. The gap between the substrate and the semiconductor chip is filled with an underfill resin, cured and fixed. The solder ball pad on the back surface may be formed on a truncated conical projection, but in order to improve the adhesion of the ball, a circuit for connecting to the ball pad is provided on the truncated conical projection and connected to this conductor. Therefore, it is preferable to make it on the portion other than the upper portion of the protrusion.
Then, the solder ball pad portion on the back surface is joined to the motherboard printed wiring board with solder balls. The heat generated from the semiconductor chip is conducted from the semiconductor chip mounting portion, passes through the truncated conical projection of the metal core, and is transmitted to the metal core,
Conduction is transmitted to the solder ball pad through the metal truncated conical protrusion on the opposite surface, and diffuses to the motherboard printed wiring board joined by the solder ball.

[0010] The side surface of the metal plate may be in a form of being embedded with the thermosetting resin composition or in an exposed form, but from the viewpoint of preventing rusting, etc. It is more preferable that it is coated with.

The through hole for the front and back signal 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. Next, a conductor layer inside the through hole is formed by electroless plating or electrolytic plating to form a plated through hole.

After the front and back circuits are formed, noble metal plating is formed on at least the surfaces of the semiconductor chip mounting portion, the bonding pad portion, and the solder ball pad portion 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. Alternatively, after plating, a film is formed on at least the surface other than the bonding pad and the opposite surface of the solder ball bonding pad with a known thermosetting resin composition or a photo-selective thermosetting resin composition as necessary.

In the case of wire bonding, a semiconductor chip is fixed on a surface metal foil in contact with the inner layer frustum-shaped metal core of the printed wiring board 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, and the solder ball is superimposed on a circuit on a motherboard printed wiring board, and the ball is melt-connected by heat. When 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 formed on the motherboard printed wiring board surface and the solder ball conductor for the P-LGA The pad and
The solder balls are connected by heating and melting.

The metal plate used in the present invention is not particularly limited, but has a high elastic modulus and a high thermal conductivity and a thickness of 30 to 100 μm, preferably 50 to 75 μm. Specifically, pure copper, oxygen-free copper, and alloys of Fe, Sn, P, Cr, Zr, .Zn and the like containing 95% by weight or more of copper are 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 truncated conical protrusion of the present invention is not particularly limited, but is preferably set to be 50 to 150 μm higher than the base metal plate. Also, the thickness of the insulating layer of the prepreg, the resin sheet, etc., is slightly lower than the height of the metal truncated conical projections after lamination molding, preferably 5 to 10 μm lower, after lamination molding, between the truncated conical projections, and The clearance hole or the slit hole is filled with resin, and the tip of the truncated conical projection is brought into contact with and joined to at least a part of the surface metal foil by pressure.

The range in which the metal truncated cone-shaped protrusions are formed is around the semiconductor chip area, and is generally within 5 to 20 mm square.
It should be present at the semiconductor chip fixing location and the opposite surface. Preferably, a ball pad is formed avoiding a portion of the metal foil in contact with the metal projection on the back surface, and the ball pad and the circuit are connected to the metal foil on the projection so that the ball pad is bonded to the substrate. Peel strength (ball shear strength) when pressure is applied to the ball from the side while maintaining strength
To be able to hold.

As the resin of the thermosetting resin composition used in the present invention, generally known thermosetting resins are used. Specifically, an epoxy resin, a polyfunctional cyanate ester resin, a polyfunctional maleimide-cyanate ester resin, a polyfunctional maleimide resin, an unsaturated group-containing polyphenylene ether resin, and the like, and one or more kinds Are used in combination. 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-cy (Anatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting novolak with cyanogen halide.

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

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

As the polyimide resin, generally known ones can be used. Specific examples thereof 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 used in 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-acrylonitrile copolymer, polychloroprene, butadiene-styrene copolymer. Polymer, polyisoprene,
Low molecular weight liquid such as butyl rubber, fluoro rubber, natural rubber, etc.
High molecular weight elastic rubbers; polyethylene, polypropylene, polybutene, poly-4-methylpentene, 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. 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 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 18 μm is used.

The diameter of the clearance hole or the width of the slit formed in the metal plate is 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 the 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 the prepreg for a printed wiring board of the present invention, the substrate is impregnated with a thermosetting resin composition and dried to obtain a semi-cured laminated material. Further, a resin sheet in a semi-cured state without using a base material can be used. Paints can also be used. The temperature for forming a semi-cured resin layer such as a prepreg is generally 100 to 180 ° C. The time is 5 to 60 minutes, and is appropriately selected depending on the desired flow rate.

The method for producing the metal core of the present invention and the printed wiring board for a semiconductor plastic package using the metal core are not particularly limited, but for example, the following method (FIGS. 1 and 2). (1) In the metal plate (a) serving as the metal core, a clearance hole (b) is punched out at a place other than the place where the semiconductor chip is fixed, and (2) a mold ( A projection with a truncated cone shape (d) is formed in c), and this surface is treated with black copper oxide. (3) On both sides, arrange the prepreg which is slightly larger than the area of the metal protrusion at the center part, heat, press, and laminate under vacuum to form a double-sided metal foil clad laminate with metal core (e) Create Then, (4) a hole is drilled in the clearance hole with a mechanical drill so as not to contact the metal core. (5) The whole is plated with copper after the desmear treatment. (6) A circuit is formed on both sides, (7) Leave the metal foil for mounting the semiconductor chip in contact with the truncated conical protrusion on the surface of the metal core, and connect the solder ball pad on the back side directly to the copper foil on the metal protrusion with a circuit avoiding the truncated cone. Circuits are formed on the front and back sides, and except for the metal foil part, bonding pad and solder ball pad part on the surface that will be the semiconductor chip mounting part, it is covered with plating resist, and nickel plating and gold plating are applied to create a printed wiring board I do. (8-1) In the case of wire bonding, a semiconductor chip is bonded and fixed to the surface with a silver paste, and after the wire bonding, at least the semiconductor chip, wires, and wire bonding pads are resin-sealed. On the back surface, a solder ball is melt-bonded to a pad to form a semiconductor plastic package. (8-2) In the case of flip-chip bonding, a heat dissipation bump is joined to a central metal foil in contact with a metal core, and a signal bump is joined to a signal propagation pad.

[0031]

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 bis (4-
100 parts of (maleimidophenyl) methane are melted at 150 ° C,
The mixture was reacted for 4 hours with stirring to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. Add bisphenol A type epoxy resin (trade name: Epicoat 1001, Yuka Shell Epoxy Co., Ltd.)
) And 600 parts of a cresol novolac type epoxy resin (trade name: ESCN-220F, manufactured by Sumitomo Chemical Co., Ltd.) were uniformly mixed and dissolved. Further, as a catalyst, zinc octylate 0.4
Was added and dissolved and mixed. To this, 500 parts of an inorganic filler (trade name: calcined talc, manufactured by Nippon Talc Co., Ltd.) was added, and uniformly mixed by stirring to obtain Varnish A. The varnish was impregnated with a 150 μm thick glass woven fabric, dried, and gelled for 50 seconds (at 170 ° C.), 1
A semi-cured prepreg B having an insulating layer thickness of 80 μm was prepared so that the resin flow was 10 mm at 70 ° C., 20 kgf / cm ² , and 5 minutes.

On the other hand, a 70 μm-thick Cu: 9
Prepare an alloy plate of 9.9%, Fe: 0.07%, P: 0.03%, size 50 mm
In addition to the semiconductor chip mounting part of the corner package, the hole diameter is 0.6 m
The clearance hole of m was opened. On the other hand, within 15 mm square of the part where the semiconductor chip in the center is mounted, using a mold from the top and bottom, 75 μm higher than the original metal plate, bottom diameter 945 μm,
Thirty-six frustoconical protrusions with an upper diameter of 212 μm and thirty-six were also formed on the back surface. The entire surface of the metal plate is subjected to black copper oxide treatment, and the semiconductor chip mounting portion of the prepreg B is 15 mm in area on the front and back surfaces.
Place one punched out corners, place the electrolytic copper foil of 12μm above and ^{below, 200 ℃, 20kgf / cm 2} , 30mmHg or less under vacuum
Lamination molding was carried out for 2 hours and integrated. A through hole with a hole diameter of 0.25 mm is drilled in the clearance hole with a mechanical drill, and after desmearing, the whole is electroless and electrolytically plated.
A circuit was formed on the front and back surfaces by applying a μm copper plating. The solder ball pad on the back was created avoiding the truncated cone.
A plating resist was formed on portions other than the semiconductor chip mounting portion, the wire bonding portion, and the ball pad portion on the back surface, and nickel and gold plating were performed thereon to complete a printed wiring board. After bonding a semiconductor chip of 13 mm square with silver paste on the heat conductive copper foil surface in contact with the tip of the truncated cone-shaped protrusion that is the semiconductor chip mounting part on the surface, wire bonding is performed, and then A semiconductor chip, a wire and a bonding pad were resin-encapsulated using a silica-containing epoxy encapsulation compound resin, and a solder ball was bonded to the back surface to produce a semiconductor package. 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.

Comparative Example 1 In Example 1, a solder ball pad on the back surface was formed on a truncated cone-shaped projection, a printed wiring board was prepared in the same manner, and joined to a motherboard printed wiring board with solder balls. Table 1 shows the evaluation results.

Comparative Example 2 Two prepregs B (FIG. 3, g) of Example 1 were used, and 12 μm electrolytic copper foils (FIG. 3, f) were arranged on the upper and lower sides at 200 ° C. and 20 kgf / c.
Lamination molding was performed for 2 hours under a vacuum of m ² and 30 mmHg or less to obtain a double-sided copper-clad laminate. A through hole having a hole diameter of 0.25 mmφ was drilled at a predetermined position, and copper plating was performed after desmear treatment. 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. This is a through hole for heat dissipation at the place where the semiconductor chip is mounted
(FIG. 3, h) is formed, and a semiconductor chip is bonded thereon with a silver paste (FIG. 3, l), and wire bonding is performed.
(FIG. 3, m) After that, using the epoxy sealing compound in Example 1,
Resin sealing (Fig. 3, j) in the same manner as above, and solder balls (Fig. 3,
o) was joined. Similarly joined to the motherboard. Table 1 shows the evaluation results.

Comparative Example 3 300 parts of an epoxy resin (trade name: Epicoat 5045, manufactured by Yuka Shell Epoxy Co., Ltd.) and an epoxy resin (trade name: E
SCN220F, manufactured by Sumitomo Chemical Co., Ltd.) 700 parts, dicyandiamide 35 parts, 2-ethyl-4-methylimidazole 1 part are dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and this is dissolved in a 100 μm thick glass woven fabric. Impregnate, dry, gel flow time 10 seconds, resin flow 98 μm no-flow prepreg (prepreg C, FIG. 4, p), and gel time 150
Seconds, resin flow 18mm high flow prepreg (prepreg
D) created. Using two prepregs D, 190 ℃,
Laminate molding was performed for 2 hours under a vacuum of 20 kgf / cm ² and 30 mmHg or less to prepare a double-sided copper-clad laminate. Thereafter, 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 C (FIG. 4, p) on the back surface. The printed circuit board with the heat radiating plate was prepared by bonding the same under heat and pressure. This slightly warped. A semiconductor chip (FIG. 4, k) is bonded directly to the heat sink with a silver paste (FIG. 4, l), and wire bonding (FIG. 4,
m), and sealed with a liquid epoxy resin (FIG. 4, j).
Similarly, it was joined to a motherboard printed wiring board. Table 1 shows the evaluation results.

[0036] Table 1 Item implementation example comparisons Example 1 1 2 3 Ball shear strength 1.5 1.0 over over (kgf) heat resistance A) normal status abnormality Not determined No change No change after moisture absorption 24hrs. No error over No change No abnormalities 48hrs. No abnormalities-No abnormalities No abnormalities 72hrs. No abnormalities-No abnormalities No abnormalities 96hrs. No abnormalities-No abnormalities Partially peeled 120hrs. No abnormalities-Partially peeled partial peelings 144hrs. No abnormalities-Partial peeling one Partial peeling 168hrs. No abnormality-Partial peeling Partial peeling Heat resistance after moisture absorption B) Normal No abnormality-No abnormality No abnormality 24hrs. No abnormality-Partial peeling Partial peeling 48hrs. No abnormality-Large peeling Large peeling large 72hrs No abnormality-Wire break 96hrs. No error-Wire break 120hrs. No problem-Wire break 144hrs. No problem---168hrs. No problem---

[0037] Table 1 (Continued) Item implementation example comparisons Example 1 1 2 3 pressure cooker treatment after the insulation resistance (Omega) normal state 5X10 ¹⁴ over 6X10 ¹⁴ 6X10 ¹⁴ 200hrs. 7X10 ¹² over 5X10 ¹² 5X10 ⁸ 500hrs . 8X10 ¹¹ over ^{4X10 11 <10 8 700hrs. 3X10} 10 over 5X10 ¹⁰ over 1000hrs. 2X10 ¹⁰ over 2X10 ¹⁰ over migration resistance Omega) normal state 5X10 ¹³ over 5X10 ¹³ 4X10 ¹³ 200hrs. 6X10 ¹¹ over 4X10 ¹¹ 3X10 ⁹ 500hrs. 7 × 10 ¹¹ over ^{5X10 11 <10 8 700hrs. 2X10} 11 over 1X10 ¹¹ over 1000hrs. 8X10 ¹⁰ over 8X10 ¹⁰ over the glass transition temperature (℃) 234 234 234 160 heat radiation (° C.) 36 over 56 48

<Measurement Method> 1) Ball Shear Strength A solder ball was attached to a ball pad having a diameter of 0.65 mm, and the strength at the time of peeling by pressing from the side was measured. 2) Heat resistance after moisture absorption A) JEDEC STANDARD TEST METHOD A113-A LEVEL3: 30 ℃ ・ 60%
After treatment at RH for a predetermined time, the presence or absence of an abnormality in the substrate after three cycles of reflow soldering at 220 ° C. was confirmed by cross-sectional observation and electrical check. 3) Heat resistance after moisture absorption B) 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. 4) Insulation resistance value after pressure cooker treatment A comb-shaped pattern between terminals (line / space = 70/70 μm) was created, and the prepregs used were placed on each of these patterns. After treatment for a predetermined time at atmospheric pressure, post-treatment was performed at 25 ° C. and 60% RH for 2 hours, and insulation resistance between terminals was measured 60 seconds after 500 VDC was applied. 5) Migration resistance The test piece of 4) was applied at 85 ° C. and 85% RH at 50 VDC, and the insulation resistance between the terminals was measured. 6) Glass transition temperature Measured by the DMA method. 7) Heat dissipation The package was bonded 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.

[0039]

According to the present invention, a metal plate having substantially the same size as a printed wiring board is arranged in a part of the printed wiring board in the thickness direction, and at least one semiconductor is provided on one surface of the printed wiring board. The chip is fixed, the metal plate and the signal transmission circuit conductor on the surface of the printed wiring board are insulated with a thermosetting resin composition, and the signal transmission circuit conductor and the semiconductor chip are connected by wire bonding or flip chip bonding. The circuit conductor on the surface of the printed wiring board and the circuit conductor or the semiconductor plastic package formed on the opposite surface of the printed wiring board are connected to the outside by a solder ball conductor. In wire bonding, at least a semiconductor chip, a wire, and a bonding pad are provided. Printed circuit board metal core used for semiconductor plastic package with resin-sealed structure In the manufacturing method, a clearance hole or a slit hole is formed in a metal plate serving as a metal core other than a portion where the semiconductor chip is mounted, and then a plurality of truncated cone-shaped protrusions are formed on the front and back sides by machining at the portion where the semiconductor chip is mounted. Is formed so as to be slightly higher than the original height of the metal core to provide a metal core manufacturing method. By forming the truncated-cone-shaped projections by machining, it can be manufactured at lower cost and in a shorter time than when formed by etching or the like, and is economical. Furthermore, a chemical treatment is applied to the entire surface of the metal core, and a prepreg, a resin sheet or a coating resin layer of a thermosetting resin composition, which is cut slightly larger than the area of the truncated cone, is disposed on both surfaces thereof, and the outside thereof is provided. After placing the metal foil, laminating it under heat and pressure and integrating it, form a circuit on the surface, open a through hole for through hole, apply metal plating after desmear treatment, The chip is fixed, preferably avoiding the solder ball pad on the back surface on the truncated conical protrusion, forming a circuit on the front and back, at least on the metal foil for mounting the semiconductor chip on the front and back, the bonding pad, except for the ball pad on the back surface. By coating with a plating resist and forming a printed wiring board with a metal core obtained by applying nickel plating and gold plating, it has excellent adhesion strength with solder balls, No moisture absorption from the lower surface of the conductor chip, heat resistance after moisture absorption, i.e. method of manufacturing a metal core to allow the provision of a printed wiring board popcorn phenomenon can be greatly improved is provided. Furthermore, by using a polyfunctional cyanate ester resin composition as a resin, the electric insulation after pressure cooker treatment, excellent in migration resistance, in addition to being suitable for mass production, improved economy, A method for manufacturing a semiconductor plastic package having a novel structure is provided.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of a double-sided copper-clad laminate used for a semiconductor plastic package containing a metal core of the present invention.

FIG. 2 is a view showing a manufacturing process of a metal core having another shape according to the present invention.

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

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

[Description of Signs] a Metal plate b Clearance hole c Mold for making truncated cones d Metal truncated cones e Double-sided copper-clad laminate with metal core f Copper foil g Prepreg B h Through holes for heat dissipation i Through holes for front and back circuit conduction Hole j sealing resin k semiconductor chip l silver paste m bonding wire n plating resist o solder ball p prepreg C

Claims (4)

[Claims] A metal plate having substantially the same size as the printed wiring board is disposed on a part of the printed wiring board in a thickness direction, and at least one semiconductor chip is fixed to one surface of the printed wiring board; The board and the signal propagation circuit conductor on the surface of the printed wiring board are insulated with a thermosetting resin composition, and the circuit conductor and the semiconductor chip are connected by wire bonding or flip chip bonding, and at least signal propagation on the surface of the printed wiring board is performed. A circuit conductor and a circuit conductor pad formed on the opposite surface of the printed wiring board or a circuit conductor pad formed for connecting the package to the outside with solder balls,
In a method of manufacturing a metal core for a printed wiring board used for a semiconductor plastic package having a structure in which a metal plate and a through hole conductor insulated by a resin composition are connected, a portion of a metal plate serving as a metal core on which a semiconductor chip is mounted In addition, a clearance hole or a slit hole is formed, and then the semiconductor chip mounting portion is formed by machining so that a plurality of truncated cone-shaped protrusions on the front and back are slightly higher than the height of the metal core. A method for manufacturing a metal core for a printed wiring board with a metal core. 2. The method according to claim 1, wherein the machining is a method of pressing a metal mold having irregularities from both sides of the metal plate to be a semiconductor chip mounting portion to provide truncated conical projections on both sides of the metal plate. A method for producing a metal core for a printed wiring board containing a metal core according to claim 1. 3. The method according to claim 1, wherein the metal plate is a copper alloy containing 95% by weight or more of copper or pure copper. 4. The printed wiring board for a semiconductor plastic package according to claim 1, wherein the thermosetting resin is a polyfunctional cyanate ester and a thermosetting resin composition containing the cyanate ester prepolymer as an essential component. Production method.