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Photoresist Material for Plasma Etching of Via Holes into Sputtered Silicon Dioxide

IP.com Disclosure Number: IPCOM000083185D
Original Publication Date: 1975-Apr-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Kluge, HC: AUTHOR

Abstract

In etching of via holes through sputtered silicon dioxide, in order to gain access to underlying metal lands, it is conventional to use buffered HF gas in conjunction with conventional photoresist materials. Problems are encountered with that method, however, in that the metal lands are subject to attack by the buffered HF. The problem becomes more pronounced when misalignment of the photoresist mask occurs, whereupon the metal lands are subject to attack on the sides as well as the top.

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Photoresist Material for Plasma Etching of Via Holes into Sputtered Silicon Dioxide

In etching of via holes through sputtered silicon dioxide, in order to gain access to underlying metal lands, it is conventional to use buffered HF gas in conjunction with conventional photoresist materials. Problems are encountered with that method, however, in that the metal lands are subject to attack by the buffered HF. The problem becomes more pronounced when misalignment of the photoresist mask occurs, whereupon the metal lands are subject to attack on the sides as well as the top.

An improved process is described for etching via holes in sputter deposited silicon dioxide by plasma or reactive ion etching, through the use of a photoresist mask composition which withstands plasma attack. Etching is carried out in a plasma of CF4 gas mixed with O(2) or N(2).

The improved photoresist is a conventional photoresist material crosslinked during a postbake operation with a thermal-free radical initiator, such as benzol peroxide. The improved physical characteristics of the photoresist obtained by a cross-linking with benzol peroxide permits the material to withstand plasma attack, and thereby enables plasma etching of the via openings.

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