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Alkali Etch Adhesion Promotion Process

IP.com Disclosure Number: IPCOM000052156D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kristoff, JS: AUTHOR [+3]

Abstract

The adhesion of photoresist to silicon oxide surfaces is a factor of major importance in the manufacture of integrated circuits. The adhesion of typical, organic-based, photosensitive resists to SiO(x), (where 0

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Alkali Etch Adhesion Promotion Process

The adhesion of photoresist to silicon oxide surfaces is a factor of major importance in the manufacture of integrated circuits.

The adhesion of typical, organic-based, photosensitive resists to SiO(x), (where 0 <X </- 2) has been significantly improved by the introduction of a "preclean/etch" consisting of the exposure of the silicon-oxide surface to a strong base, followed by a deionized water rinse and spin-dry cycle. Examples of strong bases used are 0.2M KOH, which produced a mild promotion of adhesion, and 0.5M TMAH (tetramethylammonium hydroxide), which exhibited a dramatic promotion of adhesion.

Although the exact mechanism is unknown, it is suggested that a variety of factors may contribute. For example, the strong alkali concentration may act to clean the surface by dissolving some of the surface silicon dioxide which is significantly contaminated with impurities irregardless of storage precautions. The effect of the chemical "etch" followed by an H(2)O rinse most likely results in the introduction of a fresh, homogeneous layer of hydroxyl species on the surface.

The following is a detailed example of the conditions necessary for improving the adhesive qualities of typical, novolak-based photoresists to silicon dioxide surfaces by introducing a pre-clean/etch step consisting of: 0.23M KOH or 1.0M TMAH 10-40 seconds

Deionized H(2)O 30 seconds

Spin Dry.

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