Browse Prior Art Database

Enhancement to PMMA Developer

IP.com Disclosure Number: IPCOM000103287D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Dean, A: AUTHOR [+4]

Abstract

Improvements to PMMA developers have been found which result in the elimination of random opaque defects.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Enhancement to PMMA Developer

      Improvements to PMMA developers have been found which result in
the elimination of random opaque defects.

      Random opaque defects are caused on chrome-coated glass masks
when polymethylmethacrylate resist is redeposited onto the mask after
developing.  The redeposited PMMA prevents the chrome from being
etched in all the desired areas in the subsequent process step,
resulting in increased scrap and rework.

      The occurrence of random opaque defects was traced to certain
lots of the PMMA developer, a mixture of 80% hexyl acetate and 20%
3-heptanone.  It was found that the addition of as little as 0.3%
octyl acetate to the developer eliminated redeposition of
polymethylmethacrylate resist. It is documented that PMMA solubility
decreases as molecular size of the developer increases.  Thus, the
addition of octyl acetate to the developer makes the lifted-off
resist less tacky and therefore less prone to redeposition onto the
mask.  Octyl acetate concentrations of 0.8-1.2% are typically used.

      The incidence of random opaque defects has been reduced to zero
using the enhanced developer disclosed here.

      Disclosed anonymously.