Browse Prior Art Database

Etch Completion Indication

IP.com Disclosure Number: IPCOM000075585D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Silverman, R: AUTHOR

Abstract

The complete etching of contact holes in oxide passivated integrated circuit structures can be detected, prior to photoresist removal, by providing a resistive test structure in the KEBF area of semiconductor wafers.

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Etch Completion Indication

The complete etching of contact holes in oxide passivated integrated circuit structures can be detected, prior to photoresist removal, by providing a resistive test structure in the KEBF area of semiconductor wafers.

Due to variations in etch rate and oxide thickness residual oxide is sometimes left in the contact holes formed in protective oxides, which usually is not detected until final device fabrication.

A diffused resistor having two 0.5 mil X 0.5 mil contact holes, spaced about 2-4 mils apart, placed in the KERF area of a substrate provides a convenient method of detecting etch completion. Periodic resistance measurements at the test site prior to removal of the photoresist mask, allows electrical verification of the completion of contact hole etching. Etching and measuring are repeated until low resistance is obtained. After etch completion is assured, the photoresist can be removed and metallization performed.

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