Proton and anion distribution and line edge roughness of chemically amplified electron beam resist

Nanoscale resist topography such as line edge roughness (LER) or line width roughness (LWR) is the most serious concern in sub-100 nm fabrication. Many factors have been reported to affect LER. However, the cause of LER is still unclear. We calculated proton and anion distribution of chemically amplified electron beam resists in order to make clear the cause of LER. Counter anion distribution is significantly different from proton distribution. Counter anions are inhomogeneously distributed outside a relatively smooth edge of proton distribution. This is caused by the fact that acid generators can react with low-energy (∼0eV) electrons. The inhomodeneous distribution of counter anions outside proton distribution is considered to contribute to LER formation in chemically amplified resists for post optical lithographies.

[1]  Y. Ochiai,et al.  Investigating Line-Edge Roughness in Calixarene Fine Patterns Using Fourier Analysis , 2002 .

[2]  Kenji Murata,et al.  Monte Carlo simulation of fast secondary electron production in electron beam resists , 1981 .

[3]  H. Namatsu,et al.  Line-Edge Roughness: Characterization and Material Origin , 2002, 2002 International Microprocesses and Nanotechnology Conference, 2002. Digest of Papers..

[4]  A description of random walks with collision anisotropy and with a nonconstant mean free path , 1990 .

[5]  Wen-Li Wu,et al.  Direct Measurement of the Reaction Front in Chemically Amplified Photoresists , 2002, Science.

[6]  Roderick R. Kunz,et al.  Line-edge roughness in sub-0.18-μm resist patterns , 1998, Advanced Lithography.

[7]  Study on radiation-induced reaction in microscopic region for basic understanding of electron beam patterning in lithographic process (II) relation between resist space resolution and space distribution of ionic species , 2001, Digest of Papers. Microprocesses and Nanotechnology 2001. 2001 International Microprocesses and Nanotechnology Conference (IEEE Cat. No.01EX468).

[8]  Takahiro Matsuo,et al.  Reduction of line edge roughness in the top surface imaging process , 1998 .

[9]  Shinji Okazaki,et al.  Correlation of Nano Edge Roughness in Resist Patterns with Base Polymers , 1993 .

[10]  Franco Cerrina,et al.  Line edge roughness and photoresist percolation development model , 2003 .

[11]  Takahiro Kozawa,et al.  Pulse Radiolysis Study on Proton and Charge Transfer Reactions in Solid Poly(methyl methacrylate) , 2004 .

[12]  S. Tagawa,et al.  Subpicosecond Pulse Radiolysis Study of Geminate Ion Recombination in Liquid Benzene , 2003 .

[13]  L. Onsager.  Initial Recombination of Ions , 1938 .

[14]  Takahiro Kozawa,et al.  Radiation and photochemistry of onium salt acid generators in chemically amplified resists , 2000, Advanced Lithography.

[15]  F. Cerrina,et al.  Process dependence of roughness in a positive-tone chemically amplified resist , 1998 .

[16]  Takahiro Kozawa,et al.  Relation between spatial resolution and reaction mechanism of chemically amplified resists for electron beam lithography , 2003 .

[17]  Hideo Namatsu,et al.  Influence of molecular weight of resist polymers on surface roughness and line-edge roughness , 2004 .

[18]  Takahiro Kozawa,et al.  Radiation-Induced Acid Generation Reactions in Chemically Amplified Resists for Electron Beam and X-Ray Lithography , 1992 .

[19]  A. Tanaka,et al.  Effect of Acid Diffusion on Resolution of a Chemically Amplified Resist in X-Ray Lithography , 1991 .

[20]  Shazia Yasin,et al.  Influence of polymer phase separation on roughness of resist features , 2004 .

[21]  S. Tagawa,et al.  Study on radiation-induced reaction in microscopic region for basic understanding of electron beam patterning in lithographic process (I) - Development of subpicosecond pulse radiolysis and relation between space resolution and radiation-induced reactions of onium salt , 2001, Digest of Papers. Microprocesses and Nanotechnology 2001. 2001 International Microprocesses and Nanotechnology Conference (IEEE Cat. No.01EX468).

[22]  Takahiro Kozawa,et al.  Radiation-induced reactions of chemically amplified x-ray and electron-beam resists based on deprotection of t-butoxycarbonyl groups , 1997 .

[23]  Franco Cerrina,et al.  Line edge roughness of sub-100 nm dense and isolated features: Experimental study , 2003 .

[24]  K. Funabashi,et al.  The simple exponential distribution for initial electron‐positive ion separation distances as seen in the γ radiolysis of alkanes , 1973 .

[25]  H. Fukuda.  Analysis of line edge roughness using probability process model for chemically amplified resists , 2002, 2002 International Microprocesses and Nanotechnology Conference, 2002. Digest of Papers..

[26]  R. J. Hawryluk,et al.  Energy dissipation in a thin polymer film by electron beam scattering , 1974 .

[27]  Shigeru Moriya,et al.  Study of the acid-diffusion effect on line edge roughness using the edge roughness evaluation method , 2002 .

[28]  S. Tagawa,et al.  Modeling and simulation of chemically amplified electron beam, x-ray, and EUV resist processes , 2004 .

[29]  Jangho Shin,et al.  Resist line edge roughness and aerial image contrast , 2001 .

[30]  T. Yamada,et al.  Line Edge Roughness of Developed Resist with Low-Dose Electron Beam Exposure , 2001, Digest of Papers. Microprocesses and Nanotechnology 2001. 2001 International Microprocesses and Nanotechnology Conference (IEEE Cat. No.01EX468).

[31]  Shinji Okazaki,et al.  Nano edge roughness in polymer resist patterns , 1993 .

[32]  H. Namatsu,et al.  Effect of developer molecular size on roughness of dissolution front in electron-beam resist , 2004 .

[33]  C. Szmanda,et al.  The relationship between critical dimension shift and diffusion in negative chemically amplified resist systems , 1991 .

[34]  James W. Taylor,et al.  Factors contributing to sidewall roughness in a positive-tone, chemically amplified resist exposed by x-ray lithography , 1999 .

[35]  Studies on Reaction Mechanisms of EB Resist by Pulse Radiolysis , 2000 .

[36]  Martha I. Sanchez,et al.  Deep-ultraviolet interferometric lithography as a tool for assessment of chemically amplified photoresist performance , 1998 .

[37]  Hiroki Yamamoto,et al.  Electron Dynamics in Chemically Amplified Resists , 2004 .

[38]  Kenji Yamazaki,et al.  Nanometer-scale linewidth fluctuations caused by polymer aggregates in resist films , 1997 .