Bonding is used in particular to create the visible connections in an electronic circuit with the board and thus to create contact points. This invention offers a non-destructive test procedure that can determine both simply and reliably whether a correct bond connection has been created.
This technology for testing heavy wire bonds can be used in the fabrication of electrical connections. Typically, wire bonding is used for connecting a so-called die to electrical connections of a chip housing, for example the semiconductors of an integrated semiconductor, a light emitting diode or a sensor.
Bonding is used particularly to connect the outwardly visible terminals in an electronic circuit to chip connectors via bonding wires, thereby creating contact points. When manufacturing such arrangements, it is important that the bond connections are correctly formed to guarantee the necessary current flow in operation. To ensure this, after having decided about the component arrangement checks are carried out in spot-check manner with one or more bonding connections. For this, a “shear test” is employed to verify the mechanical stability of the bonded connections, but this method has the disadvantage that the arrangements get destroyed. So, the goal of our invention was to provide a testing method and a testing apparatus, that both are simple and reliable, to determine if a correct bonding connection in a component arrangement has been formed, even in mass production.
Regarding the inventive method, the bonding connection is created between a bonding section of a bonding wire and a metal contact point. The bonding wire has a structured top-side surface in the region of the bonding section. Methods to structure the surface are described in DE102010038130. It can be recognized if the bonding connection has been produced correctly – in a way that the current flow necessary for operation as required by its function is guaranteed – by evaluating a thermogram that is provided by the testing apparatus. For testing the bonding connection, a specific voltage is applied to the bonding wire to heat the bonding connection, resulting in a specific thermogram.
Once the bonding connection was produced correctly – meaning that it is able to guarantee the current flow necessary for operation as required by its function – this can be seen by evaluating the thermogram.
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Large scale prototype
pending: DE, EP, JP, US
Technische Universität Berlin
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