JPH11345906A - Manufacture of deformed metal core for metal cored printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a metal core to be used for double sided metal clad laminate for a metal-cored semiconductor plastic package printed wiring board, which is good in adhesion with surface layer metal foil, excellent in heat dissipation and the heat resisting property after absorbing moisture. SOLUTION: Solder is printed on the position where a conical trapezoidal protrusion on the surface of a metal flat plate, an etching resist is arranged on the area other than the clearance hole forming part on the backside of the metal flat plate, and by forming an inner layer metal core by spraying an alkaline etchant at low pressure on the surface, and by spraying the alkaline etchant at higher pressure on the backside, a printed wiring board double sided metal clad laminate having excellent close contactness with the metal foil on the surface after formation of lamination, having the upper and the lower clearance holes almost in the same diameter, and having excellent insulating property of through hole and metal plate, can be obtained. As a result, the metal core to be used for the laminate can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel semiconductor plastic package having at least one semiconductor chip mounted on a small printed wiring board and having a plurality of truncated cone-shaped protrusions on one surface, The present invention relates to a method for manufacturing a metal core for a printed wiring board with a metal core having solder attached to the truncated conical protrusion. A semiconductor plastic package using a printed wiring board obtained by processing the same is used as a relatively high-wattage, multi-terminal, high-density package such as a microprocessor, a microcontroller, an ASIC, and a graphic. This 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 the through holes, moisture is absorbed by the resin adhesive containing silver powder used for fixing the semiconductor, and there is a danger of causing interlayer blisters due to heating during mounting on the motherboard and heating when removing the 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 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 The present invention provides a method of manufacturing a metal core for a semiconductor plastic package, which solves the above problems.

[0004]

According to the present invention, a frustum-shaped metal projection portion for directly fixing at least one semiconductor chip with a heat conductive adhesive, and a clearance hole for forming a front and back conduction hole. Or a prepreg, a resin sheet, a resin-coated metal foil, or a paint layer of a thermosetting resin composition in a semi-cured state is disposed on the front and back of a metal plate having slit holes formed thereon. A method for producing a metal core of a printed wiring board containing a metal core for a semiconductor plastic package, wherein the metal foil is arranged under heating and pressurizing, and is formed on a part of one side of a metal flat plate to form a truncated cone-shaped protrusion. A solder is formed by screen printing or the like, and an etching resist for forming a clearance hole or a slit hole by etching is left on the opposite surface. In the process, an etching solution with a lower pressure is sprayed on the surface on which the truncated cone is formed, and an etching solution is sprayed with a higher pressure on the opposite surface, so that the truncated cone and the clearance hole or slit hole are formed at one time. Provided is a method for manufacturing a metal core for a printed wiring board containing a metal core which can be formed simultaneously in an etching step.

Using this metal core, a semi-cured prepreg, a resin sheet, a metal foil with a resin, or a resin layer formed by coating with a paint is disposed on the front and back surfaces of the metal core. Then, it is laminated under heat and pressure to produce a double-sided metal foil-clad laminate. Using this, the printed wiring board produced is such that a semiconductor chip fixed to a metal foil on a metal core truncated conical projection with a heat conductive adhesive and a circuit conductor around the semiconductor chip are connected by wire bonding. At least, the signal propagation circuit conductor on the printed wiring board on the front surface is connected to a circuit conductor formed on the opposite surface of the printed wiring board or a connection conductor pad with the solder ball by a through-hole conductor, At least a semiconductor plastic package having a structure in which a semiconductor chip, a bonding wire, and a bonding pad are sealed with a resin, and a metal plate having substantially the same size as the printed wiring board has a substantially center in the thickness direction of the printed wiring board. And is insulated from the front and back circuit conductors by the thermosetting resin composition. A large diameter clearance hole or slit hole is drilled, the hole wall and the metal plate are insulated with a resin composition, and a plurality of truncated cone-shaped projections are formed on the lower surface of the metal foil of the semiconductor chip mounting part, with a low melting point. Connected with solder, the semiconductor chip is fixed on the surface of the metal foil with a heat conductive adhesive, and
At least one or more through-holes are directly connected to the metal of the inner layer, or connected to the metal core via holes from the back, so that the generated heat can escape to the motherboard through the heat-radiating through-holes or the conductors in the vias. By adopting the semiconductor plastic package described above, 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 can be significantly improved, and the heat dissipation can be greatly improved. In addition, a semiconductor plastic package having a novel structure that is suitable for mass productivity and has improved economic efficiency can be obtained, and the present invention has been completed.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the semiconductor plastic package of the present invention, a metal plate having good heat dissipation is arranged at substantially the center in the thickness direction of a printed wiring board, and plated through holes for conducting circuit conductors on the front and back are formed. By forming a hole having a diameter smaller than the diameter of the clearance hole or slit hole formed in the metal plate and forming the hole substantially at the center of the embedded resin, the insulation property with the metal plate is maintained.

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 present invention firstly prepares a metal plate having a metal core as a flat surface on both sides, and preferably forms a lead-free solder on a portion of the front surface where a frustoconical projection is formed by printing or the like, and the back surface has a clearance hole, or Processing is performed so that the etching resist in the portions other than the slit holes remains, and the front surface is formed with a lower pressure and the back surface is formed with a higher pressure. At the same time, a truncated cone-shaped projection is formed by etching, and a clearance hole is formed from the back surface. As an etchant, an alkaline etchant that does not dissolve solder is used. The truncated conical portion on the surface is formed below a portion corresponding to a metal foil for fixing at least one or more semiconductor chips in a range substantially equal to the area thereof. The etching pressure on the front and back surfaces of the metal plate varies depending on the desired height of the truncated cone-shaped protrusion and the thickness of the metal plate, but generally, the surface is 0.5 to 1.5 kgf / cm and the back surface is 1. The pressure is appropriately selected within the range of 0 to 2.5 kgf / cm.

[0008] The surface of the metal plate on which the metal truncated conical protrusions and the clearance holes or slit holes are formed is subjected to a known treatment as necessary so that the solder is not dissolved. Except for the tip of the truncated cone-shaped protrusion to which solder is attached, the insulating portion is formed of the thermosetting resin composition, except for the metal plate on which the surface treatment is performed and the truncated cone-shaped protrusion and the clearance hole or the slit hole are formed. The formation of the insulating portion by the thermosetting resin composition is performed by impregnating the thermosetting resin composition in a semi-cured state, placing a dried prepreg, a resin sheet, a metal foil with resin, or a paint on the front and back surfaces, as necessary. The metal foil is placed outside and laminated under heat and pressure, preferably under vacuum. The thickness of the prepreg or the like is formed by laminating and filling the clearance hole or the slit hole with a resin, and then the thickness of the solder on the metal truncated cone-shaped protruding portion is set to a thickness sufficient to melt and connect to the metal foil on the surface. .

In the clearance hole or the slit hole,
Since unfilling of the resin is likely to occur, a method in which a solventless liquid thermosetting resin composition is poured into a clearance hole or the like in advance and cured can be used, but in any method, a clearance hole or a slit in a metal plate can be used. The hole is processed so as to be filled with the thermosetting resin composition.

At least one or more through holes are directly connected to the inner metal core and used for heat dissipation, or a via hole is formed on the back surface, and the metal core and the surface metal foil on the back surface are connected to the conductor by metal plating. Or, it is filled with a heat conductive adhesive and connected.

[0011] The side surface of the metal plate may be any of a shape embedded with a thermosetting resin composition and an exposed shape. From the viewpoint of occurrence of rust and the like, it is preferable that the side surface is covered with the resin.

A hole having a small diameter is formed in a portion of the plate prepared by the above method other than the portion where the semiconductor chip is fixed, by a well-known method such as a drill or a laser, for drilling a hole for conducting the front and back circuits.

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 metal layer inside the through hole is formed by electroless plating or electrolytic plating to form a plated through hole.

Further, in the circuit forming process of the front and back sides, the metal foil portion of the semiconductor chip fixing portion which is in contact with the inner layer metal core truncated conical protrusion is left. Further, a resin layer is formed on the surface other than the metal foil portion on which the semiconductor chip is mounted, a via is formed by laser, plasma, etc., and then, if necessary, desmearing, plasma processing, near-ultraviolet processing is performed, and metal plating is performed. After the circuit is formed, a noble metal plating can be 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. Alternatively, after plating, if necessary, at least a semiconductor chip mounting portion, a bonding pad portion, and a surface other than the solder ball bonding pad portion on the opposite surface with a known thermosetting resin composition or a photo-selective thermosetting resin composition. A film is formed on

Materials used for the layer forming the blind via portion include the above-mentioned base material reinforcing prepreg, a resin-cured copper foil coated with a thermosetting resin composition on a copper foil, dried and semi-cured, or a paint. A generally known one is used. A generally known method can be used for forming a blind via. Specifically, a method of opening a via with a carbon dioxide laser, plasma, a method of opening with a photo via method, and the like can be given.

The semiconductor chip is fixed to the surface of the metal foil portion of the printed wiring board to which the semiconductor is bonded by using an adhesive or a metal powder mixed adhesive, and the semiconductor chip and the bonding pads of the printed wiring board circuit are connected by wires. Connection is made by a bonding method, and at least the semiconductor chip, bonding wires, and bonding pads 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 a solder ball to the package or 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 pads are connected by heating and melting the solder balls.

The metal plate used in the present invention is not particularly limited, but preferably has a high elastic modulus, a high thermal conductivity and a thickness of 30 to 300 μm. Specifically, pure copper, oxygen-free copper, and other alloys with 95% or more by weight of copper, such as Fe, Sn, P, Cr, Zr, and Zn, or a metal plate or the like in which the surface of the alloy is copper-plated are preferably used. used.

The height of the metal truncated cone of the present invention is 30 to 15
0 μm is preferred. In addition, as the solder to be formed on the metal plate by screen printing or the like before etching, generally known solders can be used, but from an environmental viewpoint, preferably, a lead-free solder having a melting point of 110 to 250 ° C. is used. You. Specifically, Sn-In, Sn-Bi, Sn-Ag-Bi, Sn-Zn, Sn-Bi-Cu, Sn-Ag-Cu, S
Solder such as n-Cu, Sn-Al is mentioned. The method of printing solder on the metal plate is not particularly limited, but a generally known method such as a method of placing a metal plate having a circular hole on the surface and printing molten solder in the hole may be used.
In addition, a heat conductive metal paste that is resistant to a generally known alkaline etchant may be used.

The range in which the truncated cone-shaped protrusion is formed is equal to or less than the area of the metal foil on the semiconductor chip mounting portion, and is generally 5 to 20 m.
It is formed in the range of m square. The size of the truncated cone is not particularly limited, but generally, the diameter of the truncated cone lower part is 0.1 to 5 mm, and the diameter of the upper part is 0.05 to 1 mm.

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, 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 the reaction of a polyol, a hydroxyl group-containing silicone resin and 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, natural rubber; polyethylene, polypropylene, polybutene, poly-4-methyl Penten, polystyrene, AS
Resin, ABS resin, MBS resin, styrene-isoprene rubber,
Polyethylene-propylene copolymer, 4-fluoroethylene-
6-fluorinated ethylene copolymers; high molecular weight prepolymers or oligomers such as polycarbonate, polyphenylene ether, polysulfone, polyester, and polyphenylene sulfide; and polyurethane are exemplified and used as appropriate. 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 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 18 μm is used.

The diameter of the clearance hole or slit hole formed in the metal plate is slightly larger than the diameter of the through hole for front and back conduction. Specifically, the through hole wall and the metal plate clearance hole, or the slit hole wall is 50μ
It is preferable that the distance of at least m 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 multilayer 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. Further, a resin sheet, a resin-coated metal foil or a paint in a semi-cured state without using a base material can also be used. The temperature at which a resin in a semi-cured state such as a prepreg is formed is generally 100 to 180 ° C. the time is
The time is 5 to 60 minutes, and is appropriately selected depending on the desired flow rate.

The method of producing the semiconductor plastic package containing the irregularly shaped metal core obtained by the present invention is as follows (FIG. 1). (1) A plurality of circular solders are left on the surface of the metal plate b serving as the inner layer in the area equivalent to the semiconductor chip mounting area by using lead-free solder a. The liquid etching resist c is left on the opposite surface except for the clearance hole, and (2) the surface is processed by low pressure and the back surface is processed by high pressure to form a plurality of truncated conical protrusions on the surface. Then, holes having substantially the same diameter as the upper and lower sides of the clearance hole f are formed from the back surface, and the etching resist is removed. (3) Pre-preg e is placed on the upper and lower sides, and metal foil d is placed on the outside of the pre-preg e. After heating, pressurizing and laminating under vacuum, the through hole is not brought into contact with the inner metal foil with a drill at a predetermined position. Some of the through-holes are drilled in contact with the metal core and plated with metal. (5) Create circuits up and down by a known method, cover with a plating resist, apply noble metal plating, adhere the semiconductor chip to the surface of the semiconductor chip mounting metal foil part with a heat conductive adhesive, and perform wire bonding. Then, after sealing with a resin, a solder ball is bonded if necessary.

[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,
100 parts of (maleimidophenyl) methane are melted at 150 ° C,
The mixture was reacted for 4 hours while 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 BST # 200, manufactured by Nippon Talc Co., Ltd.) was added, and uniformly stirred and mixed to obtain Varnish A. Apply this varnish to thickness 100
μm glass woven cloth and dried at 150 ℃, gel time
(at 170 ° C.) A prepreg B in a semi-cured state having a thickness of 110 μm, which was prepared so as to be 50 seconds, was obtained. Meanwhile, a copper plate with a thickness of 250 μm and a purity of 99.9% to be used as the inner metal plate was prepared, and a 20 μm thick stainless steel plate was placed on the surface in a 13 mm square semiconductor chip mounting area in the center of a 50 mm square package. 2m on board
0.3mm round hole with a hole diameter of 0.3mm
A lead-free solder consisting of tin / silver = 0.5 / 96 / 3.5wt% (melting point: 221 ° C) is melted at 260 ° C and imprinted. On the other side, a liquid etching resist is applied over the entire surface of the metal foil to a thickness of 20µm.
After drying, the film was irradiated with ultraviolet rays so as to remove the etching resist in the clearance hole, developed with a 1% sodium carbonate solution, the surface was 1.5 kgf / cm ² , and the back was
Simultaneously etched from both sides at 2.5kgf / cm ² , 16 pieces of 117μm-height truncated cone-shaped protrusions including solder were created within a 13mm square at the center of a 50mm square package, and a 0.6mmφ clearance at the same time I opened a hole. The hole diameter of this clearance hole was almost the same in the upper and lower directions.
Put the prepreg B on top and bottom, and put the thickness on both outer sides
Place 12μm electrolytic copper foil, 230 ° C, 20kgf / cm ² , 30mmHg
It was laminated and molded under the following vacuum for 2 hours and integrated. Drill a through hole with a hole diameter of 0.25 mm at the center of the clearance hole so that it does not come into contact with the metal in the clearance hole, and connect the heat dissipation through holes to the four corner inner layer metal plates. Performed by electrolysis and electroplating,
A 17 μm copper plating layer was formed in the hole. Apply a liquid etching resist on the front and back, dry, apply a positive film, expose and develop, form a front and back circuit, then form a plating resist other than the semiconductor chip mounting part, bonding pad part and ball pad part, nickel The printed wiring board C was completed by applying gold plating. A 13 mm square semiconductor chip is bonded and fixed to the surface semiconductor chip mounting part with silver paste, wire bonding is performed, and then a semiconductor chip, wire, bonding pad part is formed using a liquid epoxy resin containing silica. Was sealed with a resin to prepare a semiconductor package (FIG. 1). Table 1 shows the evaluation results of this package.

COMPARATIVE EXAMPLE 1 Two prepregs B (g) of Example 1 were used.
An electrolytic copper foil d having a thickness of μm was placed and laminated and molded at 200 ° C., 20 kgf / cm ² under vacuum for 2 hours 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 nickel plating and gold plating were performed. A through hole h for heat dissipation is formed at a place where a semiconductor chip is mounted. A semiconductor chip i is bonded on the through hole h with a silver paste, and after wire bonding, an epoxy sealing compound is used in the same manner as in the first embodiment. Resin sealing was performed (FIG. 2). Table 1 shows the evaluation results of this package.

Comparative Example 2 Epoxy resin (trade name: Epicoat 5045) 700
Part and epoxy resin (trade name: ESCN220F) 3
00 parts, 35 parts of dicyandiamide, and 1 part of 2-ethyl-4-methylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and this was dissolved to a thickness of 100 μm.
m glass woven cloth, dried and gelled for 15 minutes
A low flow prepreg C at 170 ° C. for 2 seconds was prepared. In addition, a high flow prepreg D having a gelling time of 150 seconds and a resin flow of 18 mm was prepared. Two prepregs D 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. Thereafter, a printed wiring board was prepared in the same manner as in Comparative Example 1, the mounting portion of the semiconductor chip was cut out with a counterbore machine, and a 200-μm-thick copper plate was punched out of the above-mentioned prepreg C on the back surface, and heated and heated. In the same manner, the printed circuit board with the heat radiating plate was made to adhere under pressure. This caused a slight sled. A semiconductor chip was directly bonded to the heat sink with a silver paste, connected by wire bonding, and then sealed with a liquid epoxy resin sealant (FIG. 3). Table 1 shows the evaluation results of this package.

COMPARATIVE EXAMPLE 3 When the inner metal core of Example 1 was etched, etching was performed from both the front and back surfaces at a pressure of 2 kgf / cm ² . Etching was stopped when the same height of the truncated cone was obtained. The clearance hole of the obtained metal plate has a front surface with a hole diameter of 0.3 mmφ and a rear surface with a hole diameter of 0.6 mmφ. Connected to the board.

Table 1 Item Practical example Comparative example 1 1 2 Good connectivity between the surface semiconductor chip mounting portion and the inner layer metal plate truncated conical projections ー ー Heat resistance after moisture absorption ¹⁾ Normal No abnormalities No abnormalities No abnormalities 24hrs. No abnormalities No abnormalities No abnormalities 48hrs. No abnormalities No abnormalities No abnormalities 72hrs. No abnormalities No abnormalities No abnormalities 96hrs. No abnormalities No abnormalities No abnormalities 120hrs. No abnormalities Partial peeling 144hrs. No abnormalities Partial peeling one Partial peeling 168hrs. No abnormality Partial peeling Partial peeling Heat resistance after moisture absorption ²⁾ Normal condition No abnormality No abnormality No abnormality No abnormality 24hrs. No abnormality Partial peeling Partial peeling 48hrs. No abnormality Large peeling Large 72hrs. No abnormality Wire Break Wire break 96hrs. No fault Wire break Wire break 120hrs. No fault Wire break Wire break 144hrs. No fault--168hrs. No fault--Glass transition temperature (℃) 237 235 160 Heat dissipation (℃) 36 55 48

<Measurement Method> (1) Connectivity between Semiconductor Chip-Mounted Metal Foil and Inner-Layer Metal Truncated Conical Protrusion The cross sections of the nine truncated conical protrusions were observed to determine whether or not there was connection. (2) Heat resistance after moisture absorption ¹⁾ JEDEC STANDARD TEST METHOD A113-A LEVEL3: 30 ℃ ・ 60%
After the treatment with 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) Electrical insulation 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. (4) Glass transition temperature Measured by the DMA method. (5) 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. (7) Adhesion between metal core and frustoconical metal protrusions Cross sections of all metal protrusions were observed.

[0041]

According to the present invention, a semiconductor chip is fixed to one surface of a printed wiring board, and a semiconductor circuit conductor is connected by wire bonding to a circuit conductor formed on the surface of the printed wiring board around the semiconductor chip. The signal propagation circuit conductor on the wiring board is connected to the circuit conductor formed on the opposite surface of the printed wiring board or the connection conductor pad with the solder ball by a through-hole conductor, and at least one through-hole conductor is provided. A semiconductor with a structure in which the hole is directly bonded to the metal core or connected to the back surface of the metal core by a via hole plated with metal or filled with a heat conductive adhesive, and the back surface semiconductor chip is sealed with resin. A method of manufacturing a metal core for a printed wiring board containing a metal core used for a plastic package, the method comprising forming a truncated conical projection on a smooth metal plate surface. Attach solder, attach an etching resist to the back surface except for the part where a clearance hole or slit hole is made, and etch with an alkaline etchant at a lower pressure from the front surface and at a higher pressure from the back surface. Solder adheres to the truncated cone-shaped projection, and the upper and lower clearance holes or slit holes have substantially the same diameter, and a printed wiring board using a double-sided metal foil-clad laminate is obtained by laminating. The through-hole hole wall and the metal plate are insulated by the resin composition,
The plurality of truncated conical protrusions formed at the lower portion of the semiconductor chip mounting portion are firmly connected by solder, and
Manufacture of a semiconductor plastic package in which more than one through hole is connected to the inner metal plate, or the metal core and the ball pad on the back side are joined by via holes, and the generated heat is released through this metal plate The present invention provides a method. According to the production method of the present invention, the connection reliability between the inner metal core and the surface metal foil is excellent, 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 can be significantly improved. In addition, it is possible to obtain a metal core for a printed wiring board used for a semiconductor plastic package having a novel structure, which has improved heat dissipation, is suitable for mass productivity, and has improved economic efficiency.

[Brief description of the drawings]

FIG. 1 is a manufacturing process of a metal core of Example 1 and a double-sided copper-clad laminate for a semiconductor plastic package using the same.

FIG. 2 shows a manufacturing process of the semiconductor plastic package of Comparative Example 1.

FIG. 3 shows a manufacturing process of the semiconductor plastic package of Comparative Example 2.

[Explanation of symbols]

 a Solder b Metal plate c Etching resist d Metal foil e Glass cloth base thermosetting resin layer f Clearance hole g Prepreg B h Heat dissipation through hole i Semiconductor chip j Silver paste k Bonding wire l Sealing resin m Solder ball n plating Resist o Front and back circuit conduction through hole p Prepreg C

Claims (3)

[Claims] A metal core printed wiring board for directly fixing at least one semiconductor chip with a heat conductive adhesive, a plurality of truncated conical metal protrusions, and a clearance hole for forming front and back conduction holes. A prepreg, a resin sheet, a resin-coated metal foil or a paint layer of a thermosetting resin composition in a semi-cured state is arranged on the front and back of the metal plate on which the slit holes are formed, and further, if necessary, a metal foil A method of manufacturing a metal core of a double-sided metal foil-clad laminate containing a metal core for a semiconductor plastic package obtained by laminating and molding under heat and pressure, comprising a truncated cone-shaped projection on a part of one surface of the metal plate. A solder for forming is arranged, and an etching resist for forming a clearance hole or a slit hole by etching is arranged on the opposite surface. By spraying an alkaline etchant at a lower pressure on the raised surface and spraying an alkaline etchant on the opposite surface at a higher pressure, a truncated cone-shaped projection and a clearance hole or a slit hole are simultaneously formed. A method for producing a metal core for a printed wiring board containing a metal core having an irregular shape. 2. The method for producing a metal core for a printed wiring board according to claim 1, wherein said metal plate is a copper alloy of 95% by weight or more of copper or pure copper. 3. The method for manufacturing a metal core for a printed wiring board according to claim 1, wherein said solder is a lead-free solder having a melting point of 110 to 250 ° C.