Low profile welding fixture

Details Low profile welding fixture Low profile welding fixture

1998-11-09

2001-04-24

Evans, Geoffrey S. (Department: 1725)

Electric heating

Metal heating

For bonding with pressure

C219S158000, C219S161000, C228S044300

Reexamination Certificate

active

06222151

ABSTRACT:

FIELD OF THE INVENTION
This invention relates generally to fixtures and more specifically, to a low profile welding fixture that can hold a cover on an integrated circuit housing while the cover and integrated circuit housing are hermetically sealed to each other with the welding fixture permitting the repositioning of the cover and integrated circuit housing with respect to a welding unit so that welds can be performed on different sides of the cover.
BACKGROUND OF THE INVENTION
One of the problems encountered in hermetically sealing covers for integrated circuits is that if the covers are not held in proper alignment during the welding operation, the cover may leak. If the cover leaks, the cover must be milled off and replaced, which can cause damage to the integrated circuit housing. One of the methods of holding the cover on the integrated circuit housing is to use hand pressure. Another is to form covers with a step that engages the housing. However, as there is usually limited space in the welding units and because the integrated circuit housing and cover must be rotated 90 degrees to complete the welding operation, the use of hand pressure has lead to unacceptable yields. In other cases, the use of covers with a separate engaging step is not suitable or efficient. The present invention provides a welding fixture that can hold the cover on the integrated circuit housing during a welding operation on one side of the cover and permits rotation of the cover and integrated circuit housing so that the adjacent sides of the cover can be welded to complete the hermetic sealing of the cover to the integrated circuit housing. In addition, through the use of a cantilevered lever spring, the cover and integrated circuit housing can be held in pressure engagement with each other even though there may be small clearance between the cover and the welding machine.
DESCRIPTION OF THE PRIOR ART
U.S. Pat. No. 5,716,493 discloses a spring biased clip which holds an integrated circuit on both sides during the hermetic sealing of the cover to the integrated circuit.
U.S. Pat. No. 5,517,059 discloses a device for electron beam attachment or laser welding of semiconductor subassemblies.
U.S. Pat. No. 5,632,437 discloses a method of centering a member for applying pressure to the center of the package.
U.S. Pat. No. 4,804,130 discloses a method and apparatus for sealing lids to chip carrier assembles to increase the efficiency and reliability.
U.S. Pat. No. 4,538,956 discloses an arm for griping, manipulating and releasing a workpiece.
SUMMARY OF THE INVENTION
A fixture for holding two members in alignment and also in pressure engagement with each other during partial welding of the two members to each other and for holding the members in alignment and pressure engagement with each other while the two members are repositioned in the welding machine so the welding of the members to each other can be completed. The fixture includes a magnetic base for mounting the fixture with respect to a welding unit, an extension extending from the magnetic base with the extension angularly supporting a lever spring in a cantilevered fashion with the free end of the cantilevered spring engaging a ball held in position by a magnetic holder. The ball is positioned above the members so that pressure engagement of the ball with the free end of the cantilevered spring maintains the two members in alignment and pressure engagement with each other to enable the hermetic sealing of the two members to each other or to permit angular repositioning of the two members with respect to a welding unit without having to disturb the alignment and contact between the two members.


REFERENCES:
patent: 3938797 (1976-02-01), Frederick
patent: 4050618 (1977-09-01), Angelucci et al.
patent: 4283847 (1981-08-01), May
patent: 4538956 (1985-09-01), Kalkbrenner et al.
patent: 4804130 (1989-02-01), Kwan et al.
patent: 4902868 (1990-02-01), Slee et al.
patent: 5517059 (1996-05-01), Eytcheson et al.
patent: 5632437 (1997-05-01), Vongfuangfoo et al.
patent: 5716493 (1998-02-01), Vongfuangfoo et al.
patent: 5866867 (1999-02-01), Gore

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