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Improved Adhesion of Photoresist

IP.com Disclosure Number: IPCOM000092326D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lussow, RO: AUTHOR

Abstract

In the production of microelectronic devices, selected areas of oxidized silicon are frequently protected from chemical etching with photopolymer coatings, i.e., photoresists. The chemical etching is then restricted to remove the oxide layer from the unprotected portion of the surface. The desired access hole configuration should normally have sides almost perpendicular to the substrate surface.

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Improved Adhesion of Photoresist

In the production of microelectronic devices, selected areas of oxidized silicon are frequently protected from chemical etching with photopolymer coatings, i.e., photoresists. The chemical etching is then restricted to remove the oxide layer from the unprotected portion of the surface. The desired access hole configuration should normally have sides almost perpendicular to the substrate surface.

In some cases, however, the etched holes show considerable taper or rounding at the upper edge. Since the etchants conventionally employed do not attack the photoresist, such defects are ascribed to a failure of adhesion between the resist and the oxide surface. A breakdown of the bonding causes the resist to lift away from the hole edge to allow the etchant to attack the originally protected oxide representing a failure termed undercutting.

Such adhesion of photoresists with silicon oxide surfaces is adversely affected by the presence of absorbed water molecules held to the silicon surface by coordination type bonds.

The adhesion of KPR*-2 and KTFR, a product of Eastman Kodak Co., with silicon oxide surfaces is greatly improved by vacuum outgassing of the molecular water from the surfaces of thermal silicon oxide. In a typical process, the molecular water is outgassed from the silicon oxide surface under vacuum for 30 minutes at 50 degrees C and at a pressure of about 100 millitorr. Sputtered glass surfaces also respond to a similar treat...