Postexposure-based CD shrink techniques

The postexposure-based techniques are grouped into three broad categories, namely, reflow-based. shrink techniques, chemical-based shrink techniques, and plasma-assisted shrink techniques. The reflow-based shrink techniques comprise thermally induced reflow and electron-beam heating-induced reflow of patterned resist features. The chemical-based shrink techniques comprise those techniques that either increase or decrease the sidewall thickness of already patterned resist features, thus effectively altering their critical dimension. Examples of chemical-based shrink techniques that result in an increase in the sidewall of the patterned features include techniques based on RELACS (resolution enhancement of lithography assisted by chemical shrink) and CARL (chemical amplification of resist lines).Examples of chemical-base shrink techniques that result in decrease 

Sebald, R. Sezi, R. Leuschner, H. Ahne, and S. Birkle, Chemical amplification of resist lines (CARL), Microelectronic Eng. 11, 531 (1990) M. Sebald, R. Leuschner, R. Sezi, H. Ahne, and 

The plasma-assisted shrink techniques (e.g., MOTIF ) use plasma to deposit a thin film that conformally coats contact holes and spaces printed in resists, which on dry etching result in smaller contact holes and spaces. In the remainder of this section, we provide a more detailed treatment of the postexposure-hased singlelayer exposure techniques employed in advanced resist processing. 

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