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Via Hole Etch End Point Detection

IP.com Disclosure Number: IPCOM000085052D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bohg, A: AUTHOR [+3]

Abstract

During the manufacture of multilayer Al/Cu interconnection systems with intermediate isolating layers the conducting metallic layers are connected by etched via holes. These via holes must extend fully through the isolating layer, which necessitates testing the completeness of the etching process.

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Via Hole Etch End Point Detection

During the manufacture of multilayer Al/Cu interconnection systems with intermediate isolating layers the conducting metallic layers are connected by etched via holes. These via holes must extend fully through the isolating layer, which necessitates testing the completeness of the etching process.

After via hole etching, the wafer is immersed for about 2 minutes in a solution, out of which a defined copper layer (about 150 Angstroms) is deposited on the previously bared aluminum surface. The solution is made up of: 100 ml
0.1%-CuSO(4) + 1 ml HF(5%).

If the etching time has been too short, the via hole etching step can be repeated at random, since the above-mentioned solution attacks neither aluminum nor SiO(2) nor the photoresist. Contamination by Na, K, or organic components does not occur. An increase in the copper concentration of the about 1000 Angstroms CuAl layer arranged underneath the isolating layer is negligible.

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