Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Reaction Front Induced Roughness in Chemically Amplified Photoresists

Published

Author(s)

Vivek Prabhu, Ronald L. Jones, Eric K. Lin, Joseph~undefined~undefined~undefined~undefined~undefined Lenhart, Christopher Soles, Wen-Li Wu, D L. Goldfarb, M Angelopoulos

Abstract

We have examined, with tapping mode atomic force microscopy(AFM), the effect of post-exposure bake times and developer on surface roughness using model bilayer interfaces of deuterium-labeled poly(tert-butyloxycarbonyloxy styrene) and poly(hydroxystyrene). The AFM results demonstrate the evolution of the resulting surface morphology, representative of a line edge, as the width of the deprotection front increases. As bake time increases, the average surface roughness increases from (1 to 4-5) nm, however the surfaces are not laterally homogeneous. Initially, the bilayer is smooth with residual particulates remaining from the developing stage. After short bake times, the surface possesses a dual morphology with deep pits within a shallow variable topology. The variable topology is characteristic of developed surfaces in uniformly deprotected films, independent of the level of deprotection. A histogram of depth analysis of the AFM images demonstrates that as the width of the deprotection profile increases, the profile broadens asymmetrically, producing a bimodal distribution. However, at long bake times, the overall width of the distribution has doubled the initial, unbaked, roughness and recovered a symmetrical shape. The images demonstrate that the deprotection front is spatially inhomogeneous during short bake times and evolves into a homogeneous broad front. The origin of the spatial inhomogeneity and the dual morphology are still unknown.
Citation
Polymeric Materials: Science & Engineering
Volume
87

Keywords

atomic force microscopy, photoresist, reaction front, roughness

Citation

Prabhu, V. , Jones, R. , Lin, E. , Lenhart, J. , Soles, C. , Wu, W. , Goldfarb, D. and Angelopoulos, M. (2002), Reaction Front Induced Roughness in Chemically Amplified Photoresists, Polymeric Materials: Science & Engineering, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852008 (Accessed March 29, 2024)
Created July 31, 2002, Updated October 12, 2021