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Cross‐linking of aqueous base‐developable, photosensitive polynorbornene
Author(s) -
RaeisZadeh Mehrsa,
Elce Ed,
Knapp Brian,
Kohl Paul A.
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.33273
Subject(s) - epoxy , materials science , cross link , polymer chemistry , aqueous solution , polymer , ammonium hydroxide , substrate (aquarium) , photoresist , adhesion , chemical engineering , composite material , chemistry , organic chemistry , oceanography , layer (electronics) , engineering , geology
The effect of epoxy‐based cross‐linking additives with different functionalities on the photolithographic properties, adhesion to substrates, and cross‐link density of a tetramethyl ammonium hydroxide‐developable polynorbornene‐based dielectric was investigated. Three different multifunctional epoxy additives were investigated: difunctional, trifunctional, and tetrafunctional compounds. It was found that incorporation of a small quantity (1 wt % of solution) of an ultraviolet‐absorbing tetrafunctional cross‐linker, tetraphenylol ethane tetraglycidyl ether, activated the photo‐catalyst and improved the sensitivity of a previously photosensitive polynorbornene‐based formulation by a factor of 3.7. The impact of the epoxy cross‐linkers on the physical and optical properties of the polymer formulations was evaluated. The contrast was improved from 7.37, for the control formulation, to 24.2. The polymer‐to‐substrate adhesion was also improved by addition of the tetrafunctional epoxy cross‐linker, which facilitates the development of high‐aspect‐ratio structures. Hollow‐core pillar structures in 40‐μm‐thick films with a depth‐to‐width aspect ratio of 13 : 1 were produced. The cross‐link density was studied by using swelling measurements of cured films to evaluate the average molecular weight between cross‐links. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011