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Browse Prior Art Database

Pictorial Microcircuit Testing by Differential Solvent Evaporation

IP.com Disclosure Number: IPCOM000091053D
Original Publication Date: 1969-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Wardly, GA: AUTHOR

Abstract

This technique is for testing an operating and fully processed microcircuit without modifying its structure. The technique obtains and employs the power dissipation profile of the operating microcircuit.

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Pictorial Microcircuit Testing by Differential Solvent Evaporation

This technique is for testing an operating and fully processed microcircuit without modifying its structure. The technique obtains and employs the power dissipation profile of the operating microcircuit.

Shallow pools 10 of a high vapor pressure liquid such as alcohol or acetone are formed on the surface of the microcircuit chip. The evaporation rate of the liquid at any point on the chip surface is dependent on the power dissipation around such point in circuit 12 below any passivating layer 14. The rate of evaporation is either less than or greater than the liquid depth and viscosity. The feed rate and the evaporation is balanced. The end result is an area clear of liquid around a point or line of high power dissipation. The drawing shows the chip surface having clear areas over power sources. The higher the power dissipation for a given pool depth, the further the boundary of the clear area is from the power source.

If the pool depth is maintained at a given level, a mosaic pattern appears on the chip surface. The comparison of the mosaic pattern is compared with previous mosaics formed for and representing the limits of tolerance for the particular type circuit chip being tested. The comparison provides a criterion for accepting or rejecting the chip.

To supply the chip surface with liquid, the chip can be placed in a container of the liquid to a depth such that its surface is just below the l...