AVS 55th International Symposium & Exhibition
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuA

Paper PS-TuA10
Plasma Radiation Effects on Photoresist Degradation and Depth Fluorination of Photoresists in Fluorocarbon Discharges

Tuesday, October 21, 2008, 4:40 pm, Room 304

Session: Fundamentals of Plasma-Surface Interactions I
Presenter: F. Weilnboeck, University of Maryland
Authors: F. Weilnboeck, University of Maryland
S. Engelmann, University of Maryland
R.L. Bruce, University of Maryland
G.S. Oehrlein, University of Maryland
D.G. Nest, University of California, Berkeley
D.B. Graves, University of California, Berkeley
C. Andes, Rohm and Haas Electronic Materials
D. Wang, Rohm and Haas Electronic Materials
E.A. Hudson, Lam Research Corp.
Correspondent: Click to Email

The influence of radiation generated by Ar and Ar/C4F8 plasmas on the material degradation of photoresists (PR) is studied. Blanket films of fully formulated 193nm and 248nm PR were exposed to different radiation spectra, ranging from visible to vacuum ultraviolet light. Radiation was filtered by placing the PR underneath a structure containing transparent windows with different cut-off wavelengths, i.e. borosilicate glass (310nm) or MgF2 (120nm). Thickness changes, chemical and morphological evolution of the PR surface were characterized using Ellipsometry, Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). It was found that 193nm PR is highly sensitive to radiation wavelengths between 120nm and 310nm while 248nm PR was unaffected. The evolution of surface roughness and bulk material modifications with time was also analyzed by AFM and FTIR, and will be reported. Furthermore, we investigated the effect of bulk fluorination in 193nm and 248nm PR materials. Previous observations point towards material dependent differences of fluorination depth in the bulk for materials exposed to fluorocarbon plasmas. This phenomenon is poorly understood and will be addressed by exposing the PR materials to a C4F8/90%Ar discharge followed by depth profiling. Results will be presented at the meeting.