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Effect of post‐exposure delay in positive acting chemically amplified resists: An analytical study
Author(s) -
Nalamasu O.,
Reichmanis E.,
Hanson J. E.,
Kanga R. S.,
Heimbrook L. A.,
Emerson A. B.,
Baiocchi F. A.,
Vaidya S.
Publication year - 1992
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760322104
Subject(s) - resist , materials science , lithography , x ray photoelectron spectroscopy , quenching (fluorescence) , analytical chemistry (journal) , chemical engineering , nanotechnology , chemistry , fluorescence , optics , optoelectronics , organic chemistry , physics , layer (electronics) , engineering
The lithographic performance of chemically amplified positive resists depends on controlling the delay time between the exposure and post‐exposure bake (PEB) process steps. The effect of post‐exposure delay (PED) was investigated in poly(t‐butoxycarbonyloxystyrene‐sulfone) formulated with photoacid generators (PAG) by a variety of analytical techniques including Rutherford backscattering, infrared, X‐ray photoelectron and laser ablation microprobe mass spectrometry. The results indicate that the base‐insoluble residue formed during PED is primarily a surface phenomenon and is a result of incomplete deprotection at the resist surface. It was determined that ppb levels of basic vapors present in the resist processing environment affect process performance profoundly by reacting with the photogenerated acids during PED. Isolation of resist surface from the immediate environment by means of a thin, acidic, and base‐soluble overcoat (covercoat) material dramatically alleviates the environmental effects by quenching basic airborne contaminants and improves PED latitude.