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Integrated Circuit Expedient to Insure Consistency Between DC Testing and AC Performance

IP.com Disclosure Number: IPCOM000079098D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Freed, LE: AUTHOR [+3]

Abstract

AC testing of integrated circuits is both complex and expensive. Consequently, it is desirable to avoid AC testing where possible and to utilize only DC testing. However, when using DC testing alone, the circuit being tested may have paths displaying reactance, such as capacitance, which would be alternative to the selective path which is substantially reactanceless. In order to avoid this possibility, it may be desirable to utilize expedients in the integrated circuit layer, whereby any structural fault to an element in the selected reactanceless path would probably also result in a similar fault in the undesirable alternative path displaying reactance.

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Integrated Circuit Expedient to Insure Consistency Between DC Testing and AC Performance

AC testing of integrated circuits is both complex and expensive. Consequently, it is desirable to avoid AC testing where possible and to utilize only DC testing. However, when using DC testing alone, the circuit being tested may have paths displaying reactance, such as capacitance, which would be alternative to the selective path which is substantially reactanceless. In order to avoid this possibility, it may be desirable to utilize expedients in the integrated circuit layer, whereby any structural fault to an element in the selected reactanceless path would probably also result in a similar fault in the undesirable alternative path displaying reactance.

An example of this is shown in the top view of a portion of an integrated circuit layout in the figure. Resistor R2 is in the desirable path without capacitance, while resistor R3 is in an undesirable alternative path to that of resistor R2. In the layout, resistors R2 and R3 are disposed very close to each other and parallel to each other running in the same direction. Therefore, if a structural fault in the semiconductor material occurs which will render the P-type diffusion of resistor R2 inoperative, the same structural fault will statistically be very likely to render P-type diffusion of resistor R3 also inoperative. As a result, the structural fault which will eliminate resistor R2 from the reactanceless path will also...