Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – With contact or lead
Reexamination Certificate
1999-06-04
2001-05-08
Abraham, Fetsum (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
With contact or lead
C257S048000, C257S503000, C257S673000, C257S700000, C257S758000, C257S778000, C257S781000
Reexamination Certificate
active
06229206
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a bonding pad test configuration for establishing whether or not a semiconductor chip is bonded. The configuration has a circuit that evaluates a state of a bond between a bonding wire and a bonding pad and is able to activate and deactivate operating and test modes depending on the determined bond state.
When semiconductor chips are being manufactured and when they have to pass through operating and test modes, it should always be evident whether or not the respective semiconductor chips are already reliably bonded. For this, it would be particularly advantageous if the semiconductor chip were itself able to recognize whether or not it is already bonded, so that it is then possible for the individual operating and test modes to be activated and deactivated depending on its respective fitment state. Such a property of the semiconductor chip would have the considerable advantage that it would be possible to dispense with putting the chip into an appropriate test lab, with the considerable waste of time that this entails. Until now, no-one has thought of producing a test configuration with which a semiconductor chip can itself recognize whether or not it is already bonded.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a bonding pad test configuration, which overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which a semiconductor chip is able to establish whether or not it is already bonded, in order for it to be possible to activate and deactivate respective operating and test modes depending on the bond state determined for the semiconductor chip.
With the foregoing and other objects in view there is provided, in accordance with the invention, in a semiconductor chip, a bonding pad test configuration for determining if the semiconductor chip is bonded, including:
a bonding pad divided into at least two parts; and
a circuit for evaluating a state of a bond between a bonding wire and the bonding pad, the circuit disposed in the semiconductor chip and using signals derived from the at least two parts of the bonding pad to determine if the bonding wire is in contact with the at least two parts, the circuit activating and deactivating operating and test modes in dependence on the state of the bond determined by the circuit.
The invention achieves the object with a test configuration of the type mentioned in the introduction in that the bonding pad is divided into at least two parts, so that the circuit produced in the semiconductor chip itself can use signals derived from the parts of the bonding pad to establish whether or not the bonding wire is in contact with the parts.
The bonding pad is preferably subdivided into two parts. If necessary, however, it is also possible for it to be subdivided into more than two parts.
Hence, the present invention describes a completely different approach than that of the previous prior art. The test configuration according to the invention does not establish correct bonding of bonding pads through test signals being supplied to the semiconductor chip externally by the wires connected to the bonding pads. Instead, the semiconductor chip itself tests whether or not it is already correctly bonded in that it contains a circuit which evaluates whether or not the bonding pads, which are each divided into at least two parts, are in contact with the bonding wire.
This makes use of the fact that the resistance between two parts of the bonding pad that are not connected to the bonding wire is virtually infinitely large. Whereas the resistance between two parts of a bonding pad that are electrically connected to one another by the bonding wire is around zero. Hence, the circuit provided in the semiconductor chip evaluates merely whether the resistance between the two parts is around zero or around infinity.
Such circuits can be constructed in a great variety of ways. They must merely be capable of recognizing whether or not the at least two parts of a bonding pad are conductively connected to one another by a bonding wire.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a bonding pad test configuration, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
REFERENCES:
patent: 5751015 (1998-05-01), Corbett et al.
patent: 5838023 (1998-11-01), Goel et al.
Schamberger Florian
Schneider Helmut
Abraham Fetsum
Greenberg Laurence A.
Lerner Herbert L.
Siemens Aktiengesellschaft
Stemer Werner H.
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