Laser, excimer negative image

Figure 3.72. Negative image in RD2000N resist exposed uMh a KrCl excimer laser at 222 nm (top) and negative image in RD2000N resist exposed with a XeCl laser producing 308-nm light (bottom). (Reproduced from reference 83. Copyright 1983 American Chemical Society.)...

A methacrylate terpolymer containing 35 mol% methacrylic acid units was mixed with diepoxides (Fig. 131) and triphenylsulfonium triflate and imaged in a negative mode by exposure to ArF excimer laser followed by development with 0.06% (weak) TMAH solution [383]. The aromatic epoxide was selected for imaging because the more transparent aliphatic epoxide was liquid and thus lowered the Tg of the resist film to an unacceptable level. The insolubilization mechanism was speculated to be crosslinking through acid-catalyzed esterification between the carboxylic acid and epoxide. 

Ohnishi, M. Suzuki, K. Saigo, Y. Saotome, and H. Gokan, Postirradiation polymerization of e beam negative resists Theoretical analysis and method of inhibition, Proc. SPIE 539, 62 (1985). " R.R. Kunz, M.W. Horn, R.B. Goodman, P.A. Bianconi, D.A. Smith, J.R. Eshelman, G.M. Wallraff, R.D. Miller, and E.J. Ginsberg, Surface imaged silicon polymers for 193 nm excimer laser lithogra phy, Proc. SPIE 1672, 385 (1992). 

---