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Insuring Proper Probe Contact During the Testing of Integrated Circuit Chips

IP.com Disclosure Number: IPCOM000079045D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Hubacher, EM: AUTHOR

Abstract

Testing of monolithic integrated circuit chips requires test probe contact to be made to a large number of closely spaced pads. If a probe contact fails to be made, it will probably result in the chip being rejected during testing. The present approach involves a preliminary test made to insure that test probe contacts may be made to every one of the test pads on the chip.

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Insuring Proper Probe Contact During the Testing of Integrated Circuit Chips

Testing of monolithic integrated circuit chips requires test probe contact to be made to a large number of closely spaced pads. If a probe contact fails to be made, it will probably result in the chip being rejected during testing. The present approach involves a preliminary test made to insure that test probe contacts may be made to every one of the test pads on the chip.

The approach is shown schematically in the drawing. Chip 10 includes a plurality of pads 11. These pads are connected to the circuitry on the chip proper, which is not shown, as well as to a plurality of corresponding diodes 12, preferably Schottky barrier diodes which, in turn, are connected to a common- bus line 13. If the testing of the chip is to be conducted at the wafer level, where a kerf between the chips is available, diodes 12 and bus line 13 are formed in the wafer kerf. On the other hand, if testing is to be performed at chip level, i.e., after wafer dicing, the diodes and bus line may be located within the chip proper. Bus line 13 terminates in a pad 14.

Each of the pads on the chip is given a preliminary test to determine whether proper contact is being made between pad and probe, in the following manner. Assuming that this determination is being made with respect to pad 11A, a current from current source 15 is applied through probe 16 to common pad 14, and the current flowing from pad 11A is sensed by pr...