AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP10
Deformation of ArF Photoresist and Silicon Nitride Etching using Dual Frequency Superimposed (DFS) rf Capacitive Coupled Plasma

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: D.H. Kim, Sungkyunkwan University, South Korea
Authors: D.H. Kim, Sungkyunkwan University, South Korea
S.H. Cho, Sungkyunkwan University, South Korea
J.G. Lee, Sungkyunkwan University, South Korea
N.-E. Lee, Sungkyunkwan University, South Korea
Correspondent: Click to Email
As the critical dimension (CD) of advanced CMOS devices is scaled down below 100 nm, 193 nm ArF photoresist (PR) needs to be used as a mask for various etching processes including silicon nitride (SiN) hard-mask opening. Recently, dielectric etch process using ArF photoresist mask by dual frequency superimposed (DFS) capacitive coupled plasma (CCP) has attracted a lot of attention. High frequency (HF) power is used to enhance plasma density and low frequency (LF) power is used to control ion bombardment to the wafer. During dielectrics etch process using DFS-CCP, understanding of ArF photoresist deformation is very important. It has been found that the most serious problems of the hard-mask open process with ArF PR are striation, wiggling, and agglomeration of the PR. In this study, we investigated deformation of unpatterend ArF photoresists by varying the process parameters such as HF(13.56, 27.12, and 60 MHz)/LF(2 MHz) power ratio, pressure and etch chemistry (CHF@sub3@/CF@sub4@/CH@sub2@F@sub2@/Ar/O@sub2@/N@sub2@). Characterization of surface chemical change was performed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). Surface morphological changes also investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, morphological changes of surface and line edges in ArF PR, SiN etch rate, selectivity over PR during etching of ArF PR/BARC/SiN structures were investigated. The results indicated an increased deformation by increasing the low frequency power and flow rate of Ar and O@sub2@. Effects of process parameters on the etch results will be discussed in detail.