JP2000260900A - Substrates for semiconductor plastic packages - Google Patents

Abstract

(57) [Summary] (Problem corrected) [Problem] A metal core under a semiconductor chip mounting part and a metal core under a surrounding circuit part are electrically insulated, and have a heat radiation property, a heat resistance after moisture absorption, and the like. Obtain excellent substrates for semiconductor plastic packages. SOLUTION: A semiconductor plastic package of a ball grid array using a metal core having a metal projection under a semiconductor chip mounting portion d having a flat plate, or a metal projection e having a single-sided convex shape or a double-sided convex shape, wherein at least the semiconductor chip is mounted. A metal plate portion located directly below the pad is supported by a thin metal plate portion s for holding extending from at least one corner of the metal plate frame on the outer peripheral portion, and is electrically connected to other portions of the metal plate. By adopting the separated shape, the metal core at the lower part of the semiconductor chip can be incorporated almost at the center of the substrate without falling off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel metal-core substrate for a semiconductor plastic package in which at least one semiconductor chip is mounted on a small printed wiring board. The printed wiring board obtained from the substrate is used for a relatively high wattage, multi-terminal, high-density semiconductor plastic package such as a microprocessor, a microcontroller, an ASIC, and a graphic. 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. 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 form conductor pads for connection 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 this known structure, in order to diffuse heat generated from the semiconductor to the motherboard printed wiring board,
A plated thermal diffusion through-hole is formed from the upper metal foil for fixing the semiconductor chip to the lower surface. Through the holes of the through-holes, moisture is absorbed by the resin adhesive containing silver powder used for fixing the semiconductor, and the interlayer blisters are heated by heating at the time of mounting on the motherboard and by heating at the time of removing the semiconductor components from the motherboard. There is a risk of this occurring, 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. For heat dissipation, only through holes directly below the semiconductor chip cannot sufficiently dissipate heat. Is coming. Further, the metal plate on which the semiconductor chip is directly mounted is connected to the metal plate portion having the clearance hole, and the metal core as the inner layer cannot be used as the power supply layer and the ground layer.

[0004]

SUMMARY OF THE INVENTION The present invention provides a substrate for a semiconductor plastic package having a metal core in which the above problems are improved.

[0005]

That is, according to the present invention, a metal plate is disposed at a substantially central portion in the thickness direction of a substrate, and the front and back of the metal plate are integrally insulated by a glass cloth base thermosetting resin prepreg. A signal transmission circuit and a semiconductor chip connection pad formed of copper foil are formed on one surface of the outermost layer, and a signal transmission circuit and a solder ball pad are formed on the opposite surface. A through-hole conductor for a propagation circuit is formed substantially at the center of the thermosetting resin composition embedded in the clearance hole formed in the metal plate so as not to contact the metal plate, and a part of the metal plate is grounded. Ball grid array semiconductor plastic package substrate with a metal plate as the core, which has a part of through-hole conductors and connection parts as layers or power supply layers. The metal core is supported at least by a thin metal plate portion for holding the metal plate portion located immediately below the semiconductor chip mounting pad from at least one corner of the metal plate frame on the outer periphery. And a substrate for a semiconductor plastic package, wherein the substrate is electrically separated from other portions of the metal plate. The printed wiring board using the obtained substrate can use the metal core of the inner layer for the ground layer and the power supply layer, has excellent electric and thermal conductivity, does not absorb moisture from the lower surface of the semiconductor chip, and has heat resistance after absorbing moisture. That is, the popcorn phenomenon can be greatly improved. Furthermore, by using a polyfunctional cyanate composition as a thermosetting resin, electrical insulation after pressure cooker,
It is possible to obtain a substrate for a semiconductor plastic package having a novel structure, which is excellent in migration resistance and the like, is suitable for mass production, and has improved economic efficiency.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a semiconductor plastic package, a metal plate having substantially the same size as a printed wiring board is arranged in a part of a thickness direction, and the metal plate and a circuit on the front and back sides are made of a glass cloth base material. Insulate with a thermosetting resin composition, connect a circuit conductor formed on the surface of the printed wiring board and a semiconductor chip by wire bonding or flip chip bonding, at least a signal transmission circuit conductor on the printed wiring board on the surface is A circuit conductor formed on the opposite surface of the printed wiring board or a circuit conductor pad formed for connection with the outside of the package by solder balls, and a metal plate and a through hole conductor insulated with a resin composition and connected. In wire bonding, at least
It has a structure in which a semiconductor chip, wires, and bonding pads are sealed with resin. The substrate of the present invention comprises:
It is used for a semiconductor plastic package having such a structure.

The substrate according to the present invention is a ball grid array semiconductor plastic package having a metal plate as a core in which a part of the metal plate has a connection portion with a through-hole conductor as a ground layer or a power supply layer. In the substrate for use, at least a metal plate portion directly below the semiconductor chip mounting pad is supported by a thin metal plate portion for holding extending from at least one corner of the metal plate frame on the outer peripheral portion, and The substrate is made using a metal plate that is electrically separated from other parts of the plate. In the present invention, as the thermosetting resin composition, a resin composition containing a polyfunctional cyanate ester and a cyanate ester prepolymer as essential components is preferably used.

The present invention is characterized in that the metal core of the semiconductor chip mounting portion and the surrounding metal core are electrically separated, and the outer peripheral metal core can be used for a power supply layer and the like.

In the metal core directly below the semiconductor chip mounting portion, a clearance hole is formed in the metal core, and the hole is filled with a thermosetting resin composition, and a through hole is formed substantially at the center of the thermosetting resin. It can also be used in a form that does not contact the metal core, or a form in which a through hole is directly connected to the metal core and used for heat dissipation. However, it is preferable that no hole is formed in the metal plate directly below the semiconductor chip on which the semiconductor chip is mounted, since there is no moisture absorption from the rear surface, and the popcorn phenomenon is particularly improved.

According to the present invention, trapezoidal projections are formed on both surfaces of a flat metal plate as a metal core by using a known method such as etching, punching, or cutting. A known metal core may be used, such as one having a truncated-cone-shaped metal projection or one having projections formed on the front and back surfaces. The metal core has a structure in which a metal part on which a semiconductor chip is mounted or a metal part immediately below the metal part is insulated from a surrounding metal core forming a signal propagation circuit conductor or the like. This makes it possible to form a ground layer and a power supply layer on the metal core.

As shown in FIG. 1, the metal core is formed so that the portion where the semiconductor chip in the center is mounted is finally insulated from the metal core in which the surrounding clearance holes are formed. A thermosetting resin, preferably a polyfunctional cyanate resin composition, is filled in the gaps and holes between the metal plate portion located immediately below and the metal plate frame on the outer periphery. This metal core is used as a metal core of a substrate of a printed wiring board for a semiconductor plastic package having a cross section as shown in FIG.

The method for producing the metal plate is not particularly limited,
For example, when forming a metal projection in the shape of a double-sided truncated cone, first leave an etching resist on both sides of the metal plate on the surface of the semiconductor chip mounting portion and on the opposite surface, and then etch from both sides to make the metal plate approximately half in the thickness direction. Then, a liquid etching resist is adhered to the entire surface, and a portion of the etching resist left as a protrusion in the metal protrusion forming area is left in a circular shape,
In addition, a method of forming a clearance hole or a slit hole at the same time as forming a clearance hole or a slit hole at the same time as forming a truncated conical protrusion on both surfaces by removing the etching resist in a portion to be a clearance hole or a slit hole in a circular shape and etching with an etchant from both sides to form a truncated conical projection on both surfaces. Create a metal core.

The surface of the metal plate on which the truncated conical protrusions and the clearance holes or the slit holes are formed is subjected to a surface treatment for improving adhesiveness and electric insulation such as oxidation treatment, formation of fine irregularities, and formation of a film by a known method. Apply as needed. A glass cloth base material prepreg is directly disposed on the surface-treated surface of the truncated cone-shaped protrusion, or a prepreg having a hole slightly larger than the area of the truncated cone-shaped protrusion is disposed, and a metal foil is formed outside the prepreg. Is placed and laminated under heat and pressure, preferably under vacuum, and the thermosetting resin composition of the prepreg is filled into the clearance holes or slit holes with the resin and integrated to form a substrate.

[0014] In the obtained double-sided metal foil-clad laminate, at a place where a clearance hole or a slit hole is formed, a through hole for a through hole is formed by a known method such as a mechanical drill or a laser so as not to come into contact with the metal core. , Metal plating the whole. The portion where the tip of the frustoconical projection on one side is in contact with the surface metal foil is left as a semiconductor chip mounting portion. On the opposite surface, a ball pad is formed avoiding a portion in contact with the metal protrusion. In this case, the ball pad is connected to the metal foil on the metal projection by a circuit, and a circuit is formed by a generally known method. The production method slightly varies depending on the shape of the metal core.

The semiconductor chips are connected by wire bonding or flip-chip bonding. In the case of wire bonding connection, at least the semiconductor chip mounting portion on the front surface, the bonding pad portion, and the solder ball pad portion on the back surface are covered with a plating resist, and nickel,
Apply gold plating to create a printed wiring board. afterwards,
A semiconductor chip is bonded and fixed to an upper surface of the semiconductor chip mounting portion with an electric / thermal conductive adhesive, wire-bonded, and resin-sealed to form a semiconductor plastic package. 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 mounting portion of the semiconductor chip, passes through the frustoconical projection of the metal core, is transmitted to the metal core, and passes through the frustoconical projection on the opposite surface to form a solder ball pad. And spread to the motherboard printed wiring board joined by solder balls. The above is an example, and other shapes such as (2), (3), and (4) in FIG. 3 can be similarly created. However, it is not limited to these shapes.

The side surface of the metal plate may be coated or exposed with the thermosetting resin composition, but may be formed in any shape. It is more preferable that it is coated with.

The through hole for conducting 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. 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. 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.

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 fused by heat. Alternatively, 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 conductive pads formed on the motherboard printed wiring board surface and the solder ball conductive pads for the P-LGA And
The solder balls are connected by heating and melting.

The metal plate used in the present invention is not particularly limited, but a metal plate having a high elastic modulus, a high thermal conductivity and a thickness of 30 to 500 μm is preferable. 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 trapezoidal or frustoconical projection of the present invention is not particularly limited, but is preferably 50 to 150 μm. Also, the thickness of the insulating layer of the prepreg, in the case of a truncated conical projection, is slightly lower than the height of the metal truncated conical projection after lamination molding, preferably 5 to 10μm lower, after lamination molding, at least the surface metal foil Contact with a part of In this case, a lead-free solder, a heat conductive adhesive, or the like may be adhered on the truncated cone-shaped protrusions, and the protrusions may be connected to the outer metal foil. The size of the truncated cone-shaped projection is not particularly limited, but generally, the diameter of the bottom is 0.
5-5mm, upper diameter is 0-1mm. On the other hand, a problem may occur in which the resin flows out onto the trapezoidal trapezoid and is covered with the resin. In this case, the resin that has flowed out by a generally known method such as a sand blast method after lamination molding is removed, and the metal core is removed. The surface is exposed to at least the area where the semiconductor chip is mounted. If there is a base or resin layer on the metal core on which the semiconductor chip is mounted, remove the surface base and resin layer after lamination molding by sandblasting to expose the semiconductor chip mounting part. Is also possible. The sand blasting method is a method in which fine-particle sand is sprayed at a high speed in a wet or dry method, and a resin or the like on the surface is shaved and removed.
As the particles, generally known powders such as glass beads or silicon carbide having a size of about 20 to 40 μm are used.

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 the molecule. Specific examples include 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1,6-, 1,8-, 2 , 6- or 2,7-
Dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4-dicyanatobiphenyl, bis (4-dicyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) propane, 2,2- Bis (3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-cyanatophenyl) sulfone, tris (4-cy (Anatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting novolak with cyanogen halide. In addition to these,
8, 43-18468, 44-4791, 45-11712, 46-41112,
Polyfunctional cyanate compounds described in JP-A-47-26853 and JP-A-51-63149 may also be used. Further, a molecular weight of 400 to 6,000 having a triazine ring formed by trimerization of a cyanato group of these polyfunctional cyanate compounds.
Are used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer with a catalyst such as an acid such as a mineral acid or a Lewis acid; a base such as a tertiary amine such as sodium alcoholate; or a salt such as sodium carbonate. It can be obtained by: The prepolymer also contains some unreacted monomers and is in the form of a mixture of the monomer and the prepolymer, and such a raw material is suitably used for the purpose of the present invention. Generally, it is used after being dissolved in a soluble organic solvent.

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

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 economical 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 woven or nonwoven fabrics are used. Specific examples include known glass fiber cloths such as E glass, S glass, and D glass. These may be mixed. In the present invention, generally known organic fiber cloths can be used although the strength is inferior to that of the glass substrate. Specific examples thereof include wholly aromatic polyamide fiber cloth and liquid crystal polyester fiber cloth. 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. A generally known metal foil can be used as the outermost layer. Preferably 3 to 1 thickness
8 μm copper foil, nickel foil or the like is used.

The diameter of the clearance hole or the width of the slit hole 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 and a metal foil with a resin can also be used. Alternatively, paints can be used. However, from the viewpoint of strength, a glass cloth base prepreg is optimal. The temperature for forming a resin layer such as 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 printed wiring board for a semiconductor plastic package containing a metal core of the present invention is not particularly limited, but for example, the following method. (1) After coating the entire surface of the metal plate serving as the metal core with a liquid etching resist and removing the solvent by heating, the entire surface of the resist where the semiconductor chip is to be fixed, and the area in which the metal truncated conical protrusion on the opposite surface is to be formed, is entirely covered. Leave about 1 other thickness
/ 2 etching. (2) After removing the etching resist, (3) Cover the entire surface again with a liquid etching resist, leave the etching resist in a small circular shape on the surface of the surface that will become the truncated conical projection on which the semiconductor chip is mounted, and further on the back surface Leave the resist in a small circular shape also on the part to be left as a truncated cone-shaped projection, and also leave the entire resist except the clearance hole forming part. (4) Etch with an etchant from above and below, and form a truncated cone-shaped projection on the front and back And a clearance hole is formed at the same time. (5) On both sides,
Place a prepreg with a hole slightly larger than the metal protrusion, place a copper foil on the outside, (6) Laminate under heat, pressure, vacuum, and then drill through holes for through holes (7) Copper plating the entire surface, forming a solder ball pad on the metal foil on the back surface, excluding the bonding pad and the solder ball pad portion on the back surface on the metal foil portion on the front surface that will be the semiconductor chip mounting part Cover with a plating resist, apply nickel plating and gold plating to create a printed wiring board.

On the surface, a semiconductor chip is bonded and fixed with a silver paste, and after 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.

[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 BST # 200, manufactured by Nippon Talc Co., Ltd.) was added, followed by uniform stirring and mixing to obtain Varnish A. This varnish is 100μ thick
m glass woven cloth, dried, gel time (at 170 ℃)
A semi-cured prepreg B having an insulating layer thickness of 147 μm was prepared so that the resin flow was 10 mm in 5 seconds at 170 ° C., 20 kgf / cm ² and 5 minutes.

On the other hand, Cu: 9 having a thickness of 490 μm serving as an inner metal plate
Prepare an alloy plate of 9.9%, Fe: 0.07%, P: 0.03%, size 50 mm
The etching resist was etched from both sides by 140 μm from both sides of the corner package semiconductor chip mounting portion and the area on the opposite surface thereof, and then the etching resist was dissolved and removed to obtain a metal plate C. Again, a liquid etching resist is applied to the entire surface at 25 μm, and a 300 μm diameter is formed at the central portion of the semiconductor chip mounting portion and at the portion to be formed into a truncated conical projection formed on the back surface.
Except for the etching resist in the clearance hole part, dissolve the metal plate by etching from above and below, leaving the circular etching resist of, and within the center 13 mm square of the metal plate surface,
At the same time as making 256 frustum-shaped projections with a height of 140 μm, a bottom diameter of 655 μm, and a top diameter of 199 μm, and 64 on the back, a clearance hole with a hole diameter of 0.6 mmφ was made in the outer metal plate,
Metal plate D was used. Apply black copper oxide treatment to the entire metal plate,
On the front and back surfaces of the prepreg B, place a punched-out part of the truncated cone-shaped protrusion, place 12 μm electrolytic copper foil on the upper and lower sides, at 200 ° C., 20 kgf / cm ² , under a vacuum of 30 mmHg or less. Lamination molding was carried out for 2 hours and integrated. Then 0.25mm in diameter
Drill a through hole in the clearance hole part (c) with a mechanical drill so that it does not contact the inner metal core, further mount the semiconductor chip in the center, and place the metal plate in a place insulated from the surrounding metal plate and the slit. Drill 20 holes (k) to connect, and also 8 holes (j) in the outer metal part so as to connect directly to the metal plate, after desmearing, copper plating electroless, electrolytic plating 20μm Attached. Circuits were formed on the front and back surfaces, a plating resist was formed on a part of the semiconductor chip mounting portion, a wire bonding portion, and a ball pad portion on the back surface, and nickel and gold plating were performed to complete a printed wiring board. After bonding a 13 mm square semiconductor chip (f) with silver paste (g) to the copper foil surface that has electrical and thermal conductivity in contact with the truncated conical protrusion that is the semiconductor chip mounting part on the surface Then, wire bonding (h) is performed, and then the semiconductor chip (f), wires and bonding pads are resin-sealed using a silica-containing epoxy sealing compound (i), and solder balls (m) are bonded to the back surface. A semiconductor plastic package was prepared (FIG. 3A). 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 In Example 1, a liquid etching resist having a thickness of 25 μm was adhered to the entire surface of the metal plate C, the resist was left on the convex portions on both sides, and the resist at the portions serving as clearance holes and slit portions was removed and etching was performed. Thus, in FIG. 1, a metal plate E in which both central surfaces of the metal plate are trapezoidal projections was prepared. After that, the resin is molded in the same manner, and the resin which has flowed out to the convex portion is removed by blowing sand by a sand blast method, and then a part of the convex portion serving as a semiconductor chip mounting portion, a bonding pad portion, and a ball pad portion on the back surface are formed. Was covered with a plating resist, and nickel plating and gold plating were performed to prepare a printed wiring board. Similarly, connection was made by wire bonding, sealing was performed with an epoxy compound sealing resin, and solder balls were connected to form a semiconductor plastic package (FIG. 3).
(2)). This package was processed in the same manner as in Example 1 and joined to a motherboard printed wiring board. Table 1 shows the evaluation results.

Example 3 In Example 1, a copper plate having a thickness of 200 μm was used as a metal plate, an etching resist was attached to the front and back surfaces, and the resist was removed only at portions where the clearance holes and slits would be formed, and etching was performed. Thus, a metal plate F having a clearance hole with a smooth semiconductor chip mounting portion in FIG. 1 was prepared. Using this, a black copper oxide treatment was performed, prepreg B was placed on both sides, 12 μm electrolytic copper foil was placed outside the prepreg B, and similarly laminated and formed to produce a printed wiring board and a semiconductor plastic package (FIG. 3 (3) )). Example 1
The same processing as above was carried out and joined to the motherboard. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 1 In Example 1, a metal plate (s) for holding the central semiconductor chip mounting portion was prepared without the metal plate (s). However, the central metal plate fell off, and the subsequent printed wiring board was prepared. It was impossible.

Comparative Example 2 Two prepregs B of Example 1 were used, and 12 μm electrolytic copper foil was placed on the upper and lower sides, and laminated and molded at 200 ° C., 20 kgf / cm ² , and a vacuum of 30 mmHg or less for 2 hours. A copper-clad laminate was obtained. 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 has a through hole for heat dissipation at the place where the semiconductor chip is mounted, a semiconductor chip is bonded with a silver paste on this, and after wire bonding, resin sealing is performed with an epoxy sealing compound in the same manner as in Example 1. And solder balls were joined (FIG. 4). It was joined to the motherboard as in Example 1. Table 1 shows the evaluation results
Shown in

Comparative Example 3 300 parts of epoxy resin (trade name: Epicoat 5045, manufactured by Yuka Shell Epoxy Co., Ltd.) and 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. Impregnation and drying were performed to prepare a no-flow prepreg (prepreg G) having a gelling time of 10 seconds and a resin flow of 98 μm, and a high-flow prepreg (prepreg H) having a gelling time of 150 seconds and a resin flow of 18 mm.

Using two prepregs H at 190 ° C., 20
Laminate molding was performed for 2 hours under a vacuum of kgf / cm ² and 30 mmHg or less to prepare a double-sided copper-clad laminate. After that, a printed wiring board was prepared in the same manner as in Comparative Example 2, 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 of the backflow prepreg G on the back, using
Bonding was similarly performed under heat and pressure to produce a printed wiring board with a heat sink. This slightly warped. A semiconductor chip was directly bonded to this heat sink with silver paste, connected by wire bonding, and sealed with liquid epoxy resin.
(FIG. 5). Similarly, it was joined to a motherboard printed wiring board. Table 1 shows the evaluation results.

Table 1 Item Practical example Comparative example 1 2 3 2 3 Heat resistance after moisture absorption A) Normal No abnormality No abnormality No abnormality No abnormality No abnormality No abnormality 24hrs. No abnormality No abnormality No abnormality No abnormality No abnormality 48hrs No abnormalities No abnormalities No abnormalities No abnormalities No abnormalities 72hrs. No abnormalities No abnormalities No abnormalities No abnormalities No abnormalities 96hrs. No abnormalities No abnormalities No abnormalities No abnormalities No partial peeling 120hrs. No abnormalities No abnormalities No abnormalities 144hrs. No abnormalities No abnormalities No abnormalities Partial peeling Partial peeling 168hrs. No abnormalities No abnormality No abnormalities Partial peeling Partial peeling Heat resistance after moisture absorption B) Normal No abnormalities No abnormalities No abnormalities No abnormalities No abnormalities 24hrs. Abnormalities None No abnormality No abnormality Partially peeled Partially peeled 48 hrs. No abnormality No abnormality No abnormality No abnormality Peeled Large Peeled large 72 hrs. No abnormalities No abnormalities No abnormalities No broken wires No broken wires 120hrs. No abnormalities No abnormalities No broken wires No broken wires 144hrs. No abnormalities No abnormalities No abnormalities--168hrs. No abnormalities No abnormalities No abnormalities--

Table 1 (continued) Item Practical example Comparative example 1 2 3 2 3 Insulation resistance value after treatment with pressure cooker (Ω) Normal 5 × 10 ¹⁴ 4 × 10 ¹⁴ 5 × 10 ¹⁴ 6 × 10 ¹⁴ 6 × 10 ¹⁴ 200hrs.5 × 10 ¹² 6 × 10 ¹² 5 × 10 ¹² 5 × 10 ¹² 5 × 10 ⁸ 500hrs.5 × 10 ¹¹ 5 × 10 ¹¹ 4 × 10 ¹¹ 3 × 10 ¹¹ <10 ⁸ 700hrs. 6 ^{× 10 10 5 × 10 10 5} × 10 10 4 × 10 10 over ^{1000hrs. 4 × 10 10 3 ×} 10 10 3 × 10 10 2 × 10 10 over migration resistance (Omega) normal state 5 × 10 ¹³ 6 × 10 ¹³ 5 × 10 ¹³ 5 × 10 ¹³ 4 × 10 ¹³ 200hrs.6 × 10 ¹¹ 5 × 10 ¹¹ 5 × 10 ¹¹ 4 × 10 ¹¹ 3 × 10 ⁹ 500hrs.6 × 10 ¹¹ 6 × 10 ¹¹ 6 × 10 ¹¹ 4 × 10 ¹¹ <10 ⁸ 700hrs. 2 × 10 ¹¹ 1 × 10 ¹¹ 1 × 10 ¹¹ 1 × 10 ¹¹ー 1000hrs. 9 × 10 ¹⁰ 9 × 10 ¹⁰ 9 × 10 ¹⁰ 8 × 10 ¹⁰ー Glass transition temperature (℃) 234 234 234 234 160 Heat dissipation (° C.) 32 33 41 56 48

<Measurement method> 1) Heat resistance after moisture absorption A) JEDEC STANDARD TEST METHOD A113-A LEVEL3: 30 ° C, 60%
After the treatment with RH for a predetermined time, the substrate was checked for abnormality after three cycles of reflow soldering at 220 ° C. by cross-sectional observation and electrical check. 2) 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. 3) Insulation resistance value after pressure cooker process A comb-shaped pattern between terminals (line / space = 50/50 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. 4) Migration resistance The test piece of the above 3) was applied at 85 ° C. and 85% RH at 50 VDC, and the insulation resistance between the terminals was measured. 5) Glass transition temperature Measured by the DMA method. 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.

[0042]

According to the present invention, the heat generated from the semiconductor chip is transmitted from the upper metal projection to the metal core through the heat conductive adhesive, or is bonded to the ball pad portion on the rear surface through the heat dissipation through hole. With a structure that escapes to the solder balls that have escaped and diffuses to the motherboard printed wiring board, it has excellent heat dissipation, 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 greatly improved. The present invention provides a semiconductor plastic package substrate having a novel structure, which has excellent insulation properties and resistance to migration after pressure cooker treatment, is suitable for mass production, and has improved economic efficiency. The shape of the metal core is not limited to the illustrated one.

[Brief description of the drawings]

FIG. 1 is a plan view of a metal core according to a first embodiment.

FIG. 2 shows a metal core when the metal core of Example 1 is finished to a package size. This is arranged substantially at the center in the thickness direction of the package.

FIG. 3 is a cross-sectional view of a semiconductor plastic package using the metal core of the present invention. FIG. 1A is a cross-sectional view of the semiconductor plastic package according to the first embodiment. (2) is a sectional view of the semiconductor plastic package of Example 2. (3)
FIG. 9 is a sectional view of a semiconductor plastic package according to a third embodiment. (4) A sectional view of a semiconductor plastic package using a one-sided trapezoidal metal core.

FIG. 4 is a manufacturing process diagram of a semiconductor plastic package of Comparative Example 1.

FIG. 5 is a manufacturing process diagram of a semiconductor plastic package of Comparative Example 2.

[Explanation of symbols]

 a metal plate b slit c clearance hole d semiconductor chip mounting part e metal conical projection f semiconductor chip g heat conductive adhesive h bonding wire i sealing resin j outer metal core connection through hole k semiconductor mounting metal core connection through Hole 1 Plating resist m Solder ball n Through-hole for conduction of front and back circuit 0 Through-hole for heat dissipation p Metal foil q Pre-preg Br r Pre-preg G s Holding metal part of semiconductor chip mounting part

Claims (6)

[Claims] A metal plate is disposed at a substantially central portion in the thickness direction of a substrate, and the front and back surfaces of the metal plate are insulated and integrated with a glass cloth base thermosetting resin prepreg. The signal propagation circuit and the semiconductor chip connection pad formed by the above, the signal propagation circuit and the solder ball pad are formed on the opposite surface, and the front and back are electrically coupled by through-hole conductors, and the through-hole conductor for the signal propagation circuit is formed on a metal plate. Formed substantially in the center of the thermosetting resin composition embedded in the formed clearance hole so as not to contact the metal plate, and a part of the metal plate is used as a ground layer or a part of a through hole as a power supply layer. A substrate for a ball grid array semiconductor plastic package having a metal plate having a structure having a conductor and a connection portion as a core, wherein the metal core is at least a semiconductor. A metal plate portion located directly below the pad mounting pad is supported by a thin metal plate portion for holding at least from one corner of the metal plate frame on the outer periphery, and another portion of the metal plate. A substrate for a semiconductor plastic package, wherein the substrate is electrically separated from the substrate. 2. The semiconductor plastic package substrate according to claim 1, wherein the shape of the metal core is vertically smooth. 3. The semiconductor plastic package substrate according to claim 1, wherein the shape of the metal core is a trapezoidal projection only on the semiconductor chip mounting portion or a trapezoidal projection on the back surface together with the mounting portion. 4. The substrate for a semiconductor plastic package according to claim 3, wherein said convex protrusion has a truncated cone shape. 5. The substrate for a semiconductor plastic package according to claim 1, wherein said metal plate is a copper alloy of 95% by weight or more of copper or pure copper. 6. The thermosetting resin composition according to claim 1, wherein said thermosetting resin is a thermosetting resin composition containing a polyfunctional cyanate ester and said cyanate ester prepolymer as essential components. Substrate for semiconductor plastic package.