Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – Of specified material other than copper
Patent
1991-12-30
1994-05-24
Hille, Rolf
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
Of specified material other than copper
257666, H01L 2348, H01L 2944, H01L 2960
Patent
active
053151526
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a lead frame preferably employable for a plastic sealing type integrated circuit package or the like. Further, the present invention relates to a semiconductor package using the foregoing lead frame.
BACKGROUND ART
In recent years, as a large number of semiconductor elements are highly integrated with each other and produced on a mass production line, research works have been positively conducted for developing a material employable for the semiconductor elements. In addition, it has been requested in many application fields that development works are conducted further with respect to each member for the semiconductor element in consideration of properties required for the material employable for the foregoing member and a cost level of the material.
For example, a Fe-Ni based alloy such as 42 wt % Ni-Fe, 29 wt % Ni-17 wt % Co-Fe or the like each having a thermal expansion coefficient approximate to that of the semiconductor elements has been hitherto used as a material for a lead frame used for a semiconductor package such an integrated circuit package or the like. Since expensive nickel and cobalt are used as alloy components for the iron based lead frame, there appear problems that lead frames are produced at a high cost, and an excellent property of heat radiation, i.e., excellent thermal conductivity, which is required as a number of semiconductor elements are highly integrated with each other, is not satisfactory. In view of the foregoing problems, a comparatively inexpensive copper alloy having an excellent property of heat radiation is being used as a material employable for lead frames at present. For example, a Cu-Sn based copper alloy, a Cu-Sn-Ni-Si based copper alloy, a Cu-Fe-P based copper alloy and a Cu-Sn-Ni-Si-Zn based copper alloy are used as a copper alloy employable for lead frames.
However, in a case where a plastic sealing type semiconductor package is constructed using a lead frame made of one of the aforementioned copper alloys, there arises a difficulty that a sufficiently excellent property of adhesiveness of the lead frame to a sealing plastic is hardly obtained. If the lead frame has poor adhesiveness to the sealing plastic, moisture resistance, weather resistance, erosion resistance or the like of an integrated circuit, a large scale integrated circuit or the like are affected adversely. Therefore, incorrect adhesion of the lead frame to the sealing plastic reduces reliability on an integrated circuit package, a large scale integrated circuit or the like.
For this reason, it has been strongly requested that a lead frame exhibiting an excellent property of adhesiveness to the sealing plastic is developed. In addition, it has been likewise intensely requested that a excellent reliable semiconductor package using the foregoing lead frame is developed.
The present invention has been made in consideration of the aforementioned background.
An object of the present invention is to provide a lead frame having an excellent property of adhesiveness to a sealing plastic.
Another object of the present invention is to provide a semiconductor package having an excellent reliability by using the foregoing lead frame having an excellent property of adhesiveness to a sealing plastic.
DISCLOSURE OF THE INVENTION
According to a first aspect of the present invention, there is provided a lead frame which is characterized in that the lead frame comprises a matrix for the lead frame consisting essentially of a copper based alloy containing dispersive particles, a part of the dispersive particles being distributed and exposed on the surface of the matrix, and an oxide layer formed at least on a part of the matrix for the lead frame, the part contacting with a sealing plastic, the oxide layer containing an oxide of the dispersive particles distributed on the surface of the matrix for the lead frame.
In addition, according to a second aspect of the present invention, there is provided a lead frame which is characterized in that the lead frame compri
REFERENCES:
patent: 4640723 (1987-02-01), Sugai et al.
patent: 5004581 (1991-04-01), Takagi et al.
patent: 5028282 (1991-07-01), Kubozono et al.
patent: 5149499 (1992-09-01), Kim et al.
Kuse Takashi
Nakashima Nobuaki
Clark S. V.
Hille Rolf
Kabushiki Kaisha Toshiba
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