JPH08204061A - Plastic semiconductor package - Google Patents

Abstract

PURPOSE: To provide a plastic semiconductor package of which the function defective during the surface mounting is lowered. CONSTITUTION: In a plastic semiconductor package where a semiconductor chip is bonded on a laminated board on which a circuit is formed, the semiconductor chip is electrically connected with a circuit and at least the connecting point with the semiconductor chip is sealed with a resin material, the laminated board having a humidity transmitting coefficient (JISZO2O8) of 0.60g/m<2> /24hr or less per 1mmt under the condition of 40 deg.C, 9O%RH is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention adheres a semiconductor chip to a laminated plate on which a circuit composed of opened glass cloth and thermosetting resin is formed, and at least the semiconductor chip and the connecting portion are sealed with resin. In the plastic semiconductor package obtained by the above, it is a plastic semiconductor package in which a defective rate at the time of surface mounting on a printed wiring board is remarkably reduced.

[0002]

2. Description of the Related Art Conventionally, a plastic semiconductor package using a printed wiring board using a general copper clad laminate is
One or more bare chips are attached to the surface or cavity of the printed wiring board with silver paste, and after sealing with resin by wire bonding, transfer or potting, moisture enters from the back surface of the printed wiring board due to the storage atmosphere, leaving bare chips. The silver paste adhering to is absorbed.

In the case of such a conventional plastic semiconductor package, when the moisture absorption amount of the silver paste exceeds a certain level and is surface-mounted on the printed wiring board without being dried, silver is generated due to heat shock during surface mounting. Starting from the paste, cracks occur in the sealing resin and the laminated plate. (Hereinafter, this phenomenon is referred to as the popcorn phenomenon)

[0004]

DISCLOSURE OF THE INVENTION The present invention reduces the moisture absorption of silver paste, which causes the popcorn phenomenon,
A plastic semiconductor package intended to significantly reduce the defect rate during surface mounting of the plastic semiconductor package.

[0005]

That is, according to the present invention, a semiconductor chip is adhered to a laminated plate on which a circuit is formed, the semiconductor chip and the circuit are electrically connected, and at least a connecting portion with the semiconductor chip is made of resin. In a sealed plastic semiconductor package, the moisture permeability (JIS Z 020
8) is 0.60g / m ² /0.1mmt at 40 ℃ and 90% RH.
A plastic semiconductor package characterized by using a laminated plate having a length of 24 hours or less, and preferably, the laminated plate has an air permeability (JIS L 1079) by increasing the distance between glass filaments (hereinafter referred to as opening). ) 10 cm ³ / cm ² / se
c. consisting of the following glass cloth and thermosetting resin,
The thermosetting resin has a glass transition temperature of 170 ° C. or higher,
A plastic semiconductor package characterized by containing a cyanate resin as at least one component, wherein the defect rate due to the popcorn phenomenon during surface mounting is significantly reduced.

The present invention will be described below. The present invention is a plastic semiconductor package such as a plastic pin grid array (hereinafter referred to as PGA), a plastic ball grid array (hereinafter referred to as BGA), and a laminated plate used for the plastic semiconductor package. Moisture permeability (JIS Z 0208) of 40 ° C, 90% RH
It is a plastic semiconductor package with 0.60g / m ² / 24hr per 0.1mmt.

As a method of reducing the moisture permeability of the laminated plate, there is a method of widening the gap between filaments of the glass cloth yarn (opening). The types of openable cloth include mechanically elliptical opened glass cloth such as rolls, ultrasonically opened glass cloth with solvent impregnated with glass cloth, or water jet. Examples of the glass cloth include fine glass cloth, and the air permeability of the glass cloth is 10 cm ³ / cm ² / sec. Or less according to the measurement method of JIS L 1079.

As the thermosetting resin, cyanate resin, polyvalent maleimide, epoxy resin, unsaturated polyester resin, phenol resin, diallyl phthalate resin, polyamine-bismaleimide resin, polymaleimide-isocyanate resin, and other thermosetting resins A composition obtained by appropriately mixing two or more of these; a thermosetting resin, a composition obtained by mixing two or more thereof, with polyvinyl butyral, acrylonitrile-butadiene rubber, a polyfunctional acrylate compound, and the like. Crosslinked polyethylene / epoxy resin, crosslinked polyethylene / cyanate resin, polyestercarbonate / cyanate resin, or other thermoplastic resin modified crosslinkable resin composition (IPN or semi-IPN) It is illustrated. Further, it is preferably a thermosetting resin composition containing a cyanate resin as at least one component.

Cyanate resins include 1,2-, 1,3- or
1,4-dicyanatephenylbenzene, 2,2-bis (4-cyanatephenyl) propane, 2,2-bis (3,5-dimethyl-
4-cyanatephenyl) propane, bis (4-cyanatephenyl) methane, etc., and a cyanate ester compound obtained by reacting a compound having two or more phenolic hydroxyl groups such as phenol novolac with cyanogen halide,
Examples thereof include cyanate resins such as those obtained by performing a preliminary reaction for forming a sym-triazine ring by heating or using a catalyst, and those mainly using these.

A thermosetting resin composition containing a filler can also be used. Examples of the filler include natural silica, fused silica, silica such as amorphous silica, white carbon, titanium white, aerosil,
Clay, talc, wollastonite, natural mica, synthetic mica, kaolin, aluminum hydroxide, magnesia, alumina, perlite and E-, A-, C-, L-, D
Glass fine powders such as-, S-, SII-, M-, and G20- are listed.

For other purposes, flame retardants, lubricants,
Other additives can be added. The metal foil (especially copper foil) of the present invention is not particularly limited as long as it is used for electricity, and is appropriately selected according to the application.

[0012]

The present invention will be described below with reference to examples. In the examples, "parts" and "%" are based on weight unless otherwise specified. Example 1 540 parts of 2,2-bis (4-cyanatephenyl) propane and 60 parts of bis (4-maleimidophenyl) methane at 150 ° C.
Pre-react for 130 minutes, add methyl ethyl ketone and N,
It was dissolved in a mixed solvent with N-dimethylformamide. 600 parts of bisphenol A type epoxy resin (trade name; Epicoat 1001, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 450 to 500) and 0.1 part of zinc octylate were dissolved to obtain a varnish.

An open glass cloth having a thickness of 0.1 mm (air permeability 8 cm ³ / cm ² / sec.) Was impregnated with this varnish and dried to obtain a prepreg. Two prepregs obtained above were stacked, and 18 μm electrolytic copper foil was stacked on both sides of the prepreg.
Laminate molding was performed under conditions of kgf / cm ² , 180 ° C., and 2 hours to obtain a double-sided copper-clad laminate having an insulating layer thickness of 0.2 mm.

The obtained double-sided copper-clad laminate is made into a printed board, and an epoxy-based Ag paste (Ablestick
Silicon wafer (10 mm x 10 mm) with a 965-1L)
After bonding the epoxy compound (made by Nitto Heavy Industries, Ltd.)
Molded with NT8500) and made a pseudo package. The pseudo package was subjected to moisture absorption treatment at 40 ° C., 85% RH, 48 hrs, immersed in solder at 260 ° C. for 5 seconds, and observed when heat shocked.

Example 2 360 parts of 2,2-bis (4-cyanatephenyl) propane and 40 parts of bis (4-maleimidophenyl) methane at 150 ° C.
Pre-react for 130 minutes, add methyl ethyl ketone and N,
It was dissolved in a mixed solvent with N-dimethylformamide. Brominated bisphenol A type epoxy resin (trade name;
Epicoat 1121, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 450-500) 600 parts and zinc octylate 0.1 part were dissolved to obtain a varnish.

An open glass cloth having a thickness of 0.1 mm (air permeability 8 cm ³ / cm ² / sec.) Was impregnated with this varnish and dried to obtain a prepreg. Two prepregs obtained above are stacked, and 18 μm electrolytic copper foil is stacked on both sides of the prepreg.
Lamination molding was performed under the conditions of 0 kgf / cm ² , 180 ° C. and 2 hours to obtain a double-sided copper clad laminate having an insulating layer thickness of 0.2 mm.

The obtained double-sided copper clad laminate was formed into a printed board in the same manner as in Example 1, and an epoxy-based Ag paste (965-1L manufactured by Ablestick Co.) was attached to the printed board to form a silicon wafer (10 mm × 10 mm). After the adhesion, a pseudo package was prepared by molding with an epoxy encapsulation compound (NT8500 manufactured by Nitto Heavy Industries, Ltd.). The pseudo package is 40 ℃, 85% RT, 48hrs
After moisture absorption treatment at 260 ° C., it was immersed in solder at 260 ° C. for 5 seconds, and the state when heat shock was given was observed.

Comparative Example 1 Same as Example 2 except that the air permeability of the opened glass cloth having a thickness of 0.1 mm was 15 cm ³ / cm ² / sec. Comparative Example 2 The same procedure as in Example 2 was carried out except that an unopened glass cloth having a thickness of 0.1 mm was used and the air permeability thereof was 25 cm ³ / cm ² / sec. The results of the experiment are shown in Table 1.

[0019]

[Table 1] Measurement items, etc. Actual 1 Actual 2 Ratio 1 Ratio 2 Resin composition BT / EP wt / wt 50/50 40/60 40/60 40/60 Air permeability of glass cloth (cm ³ / cm ² / sec) 8 8 15 25 Glass transition temperature (DMA method) (℃) 200 180 180 180 Moisture permeability of laminate (g / m ² / 24hrs) 0.40 0.40 0.80 1.00 Number of cracks generated during heat shock / Number of tests 0/10 0 / 10 2/10 6/10

[0020]

As is clear from the detailed description of the invention, the examples, and the comparative examples, according to the plastic semiconductor package of the present invention, a plastic semiconductor package in which the popcorn phenomenon resulting from the moisture absorption of the silver paste is remarkably improved. It can be manufactured, and its significance is extremely high.

Claims (3)

[Claims] 1. A plastic semiconductor package in which a semiconductor chip is bonded to a laminated plate on which a circuit is formed, the semiconductor chip and the circuit are electrically connected, and at least a connecting portion with the semiconductor chip is sealed with a resin, The moisture permeability (JIS Z0208) of the laminate is 0.1 mmt under the conditions of 40 ° C and 90% RH.
Plastic semiconductor package characterized by comprising using a 0.60 g / m ² / 24hr or less is laminated plate per. 2. The laminated plate is made of a glass cloth and a thermosetting resin having an air permeability (JIS L 1079) of 10 cm ³ / cm ² / sec or less formed by widening the intervals of glass filaments. Item 2. The plastic semiconductor package according to item 1. 3. The thermosetting resin has a glass transition temperature of 170
2. The plastic semiconductor package according to claim 1, wherein the temperature is not less than C and the cyanate resin is at least one component.