Chemically amplified, positive tone, cross-linkable thick-film polymer

Autor: Paul A. Kohl, Brennen K. Mueller
Rok vydání: 2013
Předmět:
Zdroj: Journal of Applied Polymer Science. 130:759-765
ISSN: 0021-8995
DOI: 10.1002/app.39225
Popis: A new class of positive tone, permanent materials has been demonstrated, which are chemically amplified (CA), aqueous- developable, and cross-linkable. The intended purpose is a patterning and cross-linking method to create high sensitivity permanent dielectrics for microelectronic devices and packages. The photochemistry is based on traditional CA, acid-catalyzed deprotection of a protected organic functionality to yield an aqueous base soluble group such as a carboxylic acid or alcohol. This CA chemistry pro- duces high contrast and high photo-speed patterning, which is especially valuable for thick-film applications where high UV exposure doses are required for non-CA materials. The photospeed is about an order of magnitude faster than commercial materials at a simi- lar thickness. Subsequent to patterning, the remaining films or features can be cross-linked by a variety of chemical mechanisms. The working photo-patterning and cross-linking mechanisms are demonstrated on a random copolymer of tert-butyl methacrylate (TBMA) and 2-hydroxyethyl methacrylate (HEMA). The optical contrast (at 248 nm) was found to be 12.7 and the sensitivity, D100, was calculated to be 50.2 mJ/cm 2 in a 9.07-lm-thick film. Undeveloped regions were cross-linked after patterning. The esterification reaction is much slower than the TBMA deprotection, so that the cross-linking reaction does not interfere with the photopatterning. Cross-linking was also evident by the change in thin film stress 6.2 to 17.9 MPa during a thermal cure. Other polymers for Fischer esterification are discussed with their advantages and disadvantages along with other cross-linking chemistries. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 759-765, 2013
Databáze: OpenAIRE
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