In this paper, we investigate the capabilities to form small contact holes with various 193nm resists applying a thermal flow process. We first compare the material properties (glass transition temperature Tg and thermal deprotection T_D) of different 193nm resists to our reference process for thermal reflow, namely the 248nm reference resist (RoR). The main difficulty related to 193nm acrylate backbone is the high Tg value, which implies some flow bake temperature closed to or superior to the deprotection temperature. Depending on the resist chemistry, different behaviours have been observed such as acceleration of the flow rate, formation of bubble defects linked to gaseous by-products or even contact hole diameter increase. These results are strongly dependent on the chemical reactions occurring in the resist film at the same time as the film softening. In order to better select the most promising 193nm resist candidates for contact hole reflow technique, we also develop a polymer flow measurement with Dynamic Mechanical Analysis (DMA). By measuring the creep compliance of the resist film spin-coated onto a silicon wafer under various bake temperatures, we are able to define the optimal temperature range for resist flow.

Date Published: 2 April 2007
PDF: 10 pages
Proc. SPIE 6519, Advances in Resist Materials and Processing Technology XXIV, 65193A (2 April 2007); doi: 10.1117/12.711678

Published in SPIE Proceedings Vol. 6519:
Advances in Resist Materials and Processing Technology XXIV
Qinghuang Lin, Editor(s)