Metal fusion bonding – With means to juxtapose and bond plural workpieces – Wire lead bonder
Reexamination Certificate
1999-02-05
2001-06-19
Shaw, Clifford C. (Department: 1725)
Metal fusion bonding
With means to juxtapose and bond plural workpieces
Wire lead bonder
C228S009000, C228S104000, C228S180500
Reexamination Certificate
active
06247629
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to wire bonding of integrated circuit devices and particularly to techniques for monitoring wire bonders utilized in connection with making layered packages.
Layered packages are widely utilized in the electronics industry for packaging a variety of devices. They can include laminate packages and single-layered and multi-layered packages. Exemplary laminate packages include those without leadframes such as multichip modules including the MCM-L, MCM-C, and MCM-D packages, without excluding cerdip style packages.
Wire bond machines are used to make connections between various components of layered and non-layered electronic packages. One conventional technique, known as gold ball bonding, involves applying a molten metal ball to a bond location on a die. A ceramic capillary, for example, is then pulled from the bonded ball to a second bond location on a package and a bond is then formed to a lead on the package. The wire is then ripped from the lead, leaving two metal bonds connected by a wire.
Another conventional technique, known as aluminum wedge bonding, uses a wedge that feeds a wire through a clamp. Ultrasonic energy may be used to wedge bond the aluminum wire to form the first bond. The wedge rises, forms a wire loop, moves to the second bond site and forms a second bond like the first bond. The clamp pivots away from the tool to tear the wire at the second bond.
A large number of these connections may be made between a die and a laminate package. Testing of the packaged part for a variety of defects is normally done after the packaging process is complete. Defects may arise from poor bonds, or the total absence of a bonding wire. Poor bonds may occur, for example, due to adhesion problems or due to improper deformation of the wire.
Continuity tests in packages using leadframes are relatively straightforward. Since the leadframe is effectively located in one easily accessible strata, it can readily be accessed for testing to determine whether or not good bonds are made.
Because layered packages are tested after manufacturing, the packaged devices must sometimes be discarded because the bonds were not good. Thus, it would be desirable to have a practical technique for monitoring the wire bond apparatus used to make layered packages.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a method for wire bonding a layered package having a die and a laminate package comprises the step of making a wire bond to a die. A wire bond is also made to the laminate package. The continuity of the wire bonds to the die and the laminate package are then checked.
In accordance with another aspect of the present invention, a method for wire bonding layered packages having a die and a laminate package includes the step of securing the die to the laminate package. A wire bond connection is made from the die to the laminate package. The continuity of that connection is checked by making an electrical connection to ground through the wire bonder.
In accordance with still another aspect of the present invention, a method for wire bonding layered packages having a die and a laminate package includes the step of securing the die to the laminate package. A wire bond connection is made from the die to the laminate package. The continuity of the connection is checked by making electrical contact to the laminate package through the wire bond clamp and applying a drive signal through the wire bond connection.
In accordance with yet another aspect of the present invention, a wire bond monitoring apparatus includes a continuity tester electrically connectable to a die and a laminate package. A flexible contact is electrically connected to the continuity tester. The flexible contact is arranged to flexibly contact the laminate package to make electrical connection for testing.
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Gochnour Derek J.
Jacobson John O.
Thummel Steven G.
Micro)n Technology, Inc.
Shaw Clifford C.
Stoner Kiley
Trop Pruner & Hu P.C.
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