Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Patent
1995-09-07
1998-07-21
Ortiz, Angela Y.
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
26427215, 26427217, 264277, B29C 4502
Patent
active
057831343
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method of resin-sealing semiconductor device, comprising a circuit board with an IC mounted thereon, with thermoset resin, and, in particular, to a pinpoint gate method suitable for a transfer mold, whereby the resin is fed from below by a plunger.
Resin-sealed semiconductor devices with a plurality of electrodes have been developed in recent years as the high density mounting of IC chips progresses, A typical example of such a device is a PGA (pin grid array). The PGA has a circuit board with an IC chip mounted on one of the surfaces and sealed with resin and a plurality of pins positioned on the other surface and connected to the IC chip. Although the PGA has the advantage of being dismountably installed on a mother board, its size is large because of the existence of the pins and it is difficult to make it small.
Accordingly, a pad array carrier (hereinafter referred to as a PAC), whereon a pad is provided in place of the pins, has been developed as a small semiconductor device sealed with resin to replace the PGA.
However, sealing the semiconductor device with resin involves the risk of cutting wires due to poor mobility of molten resin. Thermoplastic resins are unsuitable for this application because the reliability of the seal after fabrication is poor. Therefore, thermoset resins which exhibit good mobility, high forming precision and reliability after sealing are used.
For molding a thermoset resin, a side gate system has been quite widely adopted as a gate system used for the resin forming metal mold, rather than a pinpoint gate system.
Normally, when a thermoset resin is molded using the side gate system, a sealed section 61 is formed by filling a cavity 55 with a thermoset resin 58 which has passed through a gate 60, as shown in FIG. 14. After the thermoset resin 58 has hardened, an upper metal mold 54 is separated from a lower metal mold 51, and an IC module 63 with a sealed section 61 formed thereon is removed together with the runner resin.
When the removed IC module 63 is separated from the runner resin, a gate remnant 64 connected to the sealed section 61 is formed as shown in FIG. 15. Therefore, it is necessary to remove the gate remnant 64. However, there is the problem that when the gate remnant 64 is removed a wiring pattern is destroyed, cracks are produced in the resin forming the sealed section, and the surface of the circuit board is contaminated with resin because the resin from the gate section runs onto and hardens on the surface of the circuit board.
For this reason, the pinpoint gate system which can eliminate the problems associated with the side gate system has been adopted for forming the PAG with thermoset resin.
However, when the thermoset resin is formed using a metal mold of the pinpoint gate system, the resin tends to plug the gate opening. In order to eliminate this problem, a metal mold which is provided with a runner lock pin for disengaging the resin from the gate opening after molding is used.
This forming method will now be explained with reference to FIG. 16.
A circuit board 53 to which an IC 52 is bonded is set between an upper metal mold (a mounting plate 80, a stripper plate 75, and a cavity block 73) which is heated to a specified temperature, for example, about 165.degree. C., and a lower metal mold (a movable side plate 71). A thermoset resin tablet 81 heated to a specified temperature is fed into a cull section 76 from a pot 82 of a plunger P. Following this, the thermoset resin is caused to flow from the cull section 76 into a cavity 74 through a lateral runner section 77 and a gate section 79 of a vertical runner section 78, by pressing the plunger P.
After the thermoset resin has been filled into the metal mold and held for a specified thermosetting time, for example, about 90 sec, the mold is opened and its engagement with the runner resin is released. Specifically, as shown in FIG. 17, first, the stripper plate 75 and the cavity block 73 are separated, and in order to pull away the runner
REFERENCES:
patent: 4954308 (1990-09-01), Yabe et al.
patent: 4961893 (1990-10-01), Rose
patent: 5071334 (1991-12-01), Obara
patent: 5215759 (1993-06-01), Juskey et al.
patent: 5286426 (1994-02-01), Rano, Jr. et al.
patent: 5302805 (1994-04-01), Hara
patent: 5344795 (1994-09-01), Hashemi et al.
patent: 5370517 (1994-12-01), Casati et al.
patent: 5424251 (1995-06-01), Sono et al.
patent: 5444909 (1995-08-01), Mehr
patent: 5510074 (1996-04-01), Rose
patent: 5563103 (1996-10-01), Komatsu
Asaumi Kazuhiko
Ikai Katsuhiko
Nayuki Teruo
Shimizu Hiroaki
Yabe Isao
Citizen Watch Co. Ltd.
Ortiz Angela Y.
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