Active solid-state devices (e.g. – transistors – solid-state diode – Encapsulated – With specified encapsulant
Reexamination Certificate
1999-12-01
2001-07-03
Thomas, Tom (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Encapsulated
With specified encapsulant
C257S787000, C257S789000, C257S794000, C257S795000
Reexamination Certificate
active
06255739
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device having a semiconductor element sealed with a resin, and more specifically, to a semiconductor device having a highly recyclable package. The present invention further relates to a thermoplastic resin composition excellent in adhesiveness to a carrier member such as a leadframe.
Conventionally, it is known that a semiconductor device is formed by mounting a semiconductor element on a leadframe and thereafter sealing the semiconductor element with a thermosetting resin. Such a semiconductor device is formed as follows.
A leadframe having a semiconductor element mounted thereon is placed in a cavity formed by combining an upper mold and a lower mold. The semiconductor element is electrically connected to the leadframe by, for example, a bonding wire. Then, an epoxy resin (thermosetting resin) is injected through an injection port (gate) facing within the cavity. The epoxy resin thus injected is heated to solidify, with the result that the semiconductor element and the leadframe are integrated into one body. As described, the thermosetting resin is widely employed in manufacturing the semiconductor device since the thermosetting resin has a good flowability and adhesiveness.
However, when the thermosetting resin is cured, nearly 60 seconds in average is required until a curing reaction is completed. Due to the long reaction, the semiconductor device decreases in productivity. In addition, since the flowability of the thermosetting resin is too high, burrs are easily produced. Furthermore, once the thermosetting resin is heated, original flowability cannot be brought back. Therefore, the thermosetting resin cannot be recycled. Consequently, when the semiconductor devices using the thermosetting resin become out of use, they have no choice but to be subjected to the land-fill disposal or incineration disposal.
To reduce the curing time, it is considered to use a thermoplastic resin in place of the thermosetting resin. When the thermoplastic resin is used, it is estimated to take 10 seconds for curing. If the thermoplastic resin is used, the original flowability of the thermoplastic resin can be brought back by heat treatment. The thermoplastic resin is therefore advantageous in view of the recycle use.
However, compared to the thermosetting resin, the thermoplastic resin has low adhesion properties to the leadframe, so that moisture contents and oily contents may enter through an interface between the leadframe and the resin. Since the thermoplastic resin has a problem of low moisture resistance, it has not conventionally been used.
In addition, the thermoplastic resin has a large linear expansion coefficient, so that stress is applied to the semiconductor element after solidification. As a result, cracks are produced in the semiconductor element.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a highly reliable thermoplastic resin composition having high adhesion properties to a leadframe and a semiconductor element and generating no cracks in the semiconductor element.
According to the present invention, there is provided a resin composition containing a thermoplastic resin as a main component and having a line expansion coefficient of 4.75×10
−5
[1/°C.] or less at a temperature of 150° C. to 200° C. and a line expansion coefficient of 6.0×10
−5
[1/°C.] or less at 80-200° C.
According to the present invention, there is provided a resin composition containing a thermoplastic resin as a main component, in which a line expansion coefficient ratio between a flow direction and a normal direction of the flow direction is 0.55 or more.
According to the present invention, there is provided a resin composition containing polyphenylene sulfide in which a line expansion coefficient at 150° C. to 200° C. is of 4.75×10
−5
[1/°C.] or less, a line thermal expansion coefficient at 80 to 130° C. is 6.0×10
−5
[1/°C.] or less, and a line expansion coefficient ratio after solidification between a flow direction and a normal direction of the flow direction is 0.55 or more.
According to the present invention, there is provided a semiconductor device and a method of manufacturing the semiconductor device which uses a thermoplastic resin composition to seal a semiconductor element and a lead frame, and has good properties equivalent to a semiconductor device formed of a thermosetting resin.
The semiconductor device has a semiconductor element, a semiconductor sealing resin composition for sealing the semiconductor element; and a conducting material electrically connected to the semiconductor element an end of which is sealed with the semiconductor sealing resin composition.
The method of manufacturing a semiconductor device comprises a step of electrically connecting a semiconductor element to a conducting material, and a step of sealing the semiconductor element with the semiconductor sealing resin composition.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
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Adachi Masaki
Yamamura Megumi
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kabushiki Kaisha Toshiba
Parekh Nitin
Thomas Tom
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