Consideration of silylation contrast in an ArF liquid-phase silylation process

• Published in: Japanese Journal of Applied Physics 1997-12, Vol.36 (12B), p.7637-7641
• Main Authors: MATSUO, T, OHKUNI, M, ENDO, M
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Microelectronic fabrication (materials and surfaces technology); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/jjap.36.7637

We have studied what determines the silylation contrast for the liquid-phase silylation process in ArF excimer laser lithography. In the liquid-phase silylation, the diffusion kinetics is dependent on the concentration of the diffusion promoter, which acts as the relaxation of the polymer film. The silylating condition of a proper concentration induces the equilibrium state of relaxation and diffusion: Case II diffusion. It was found that the Case II diffusion condition resulted in a higher silylation contrast. Next, attention was paid to the photo-crosslinking density for improving the silylation contrast. The soft-baking temperature had an influence on the crosslinking density. The densification of the polymer film by soft-baking increases the photo-crosslinking density, but an extreme densification decreases it, when the soft-baking temperature is near glass transition temperature ( T g ). It is considered that the arrangement of the polymer chains is closely linked with the efficiency of photo-crosslinking.