Quadratic nonlinear optics to assess the morphology of riboflavin doped chitosan for eco-friendly lithography

Abstract

We report the use of the Second Harmonic Generation response from a riboflavin doped chitosan film as a characterization method of the film morphology. This film is of particular interest in the development of new and bio-sourced material for eco-friendly UV lithography. The method allows us to determine how riboflavin is distributed as a function of film depth in the sample. This possibility is of importance in order to have a better understanding of the riboflavin influence in chitosan films during the lithography process. On the contrary, linear optical techniques provide no information beyond the mere confirmation of the riboflavin presence.

Chitosan as a Water-Developable 193 nm Photoresist for Green Photolithography

“…It was shown recently that chitosan and chitosan salts can be used without chemical modification as a positive resist for 248 nm or e-beam lithography. − In this paper, we show that we can achieve photopatterning of raw chitosan at 193 nm and that the patterned chitosan is suitable for dry etching and can be transferred into silica by dry etching. In this frame, chitosan appears thus as an ideal candidate for replacing commercial synthetic resists, as it does not need additional modifications, and development of patterns can be achieved with water or a slightly acidified solution after 193 nm irradiation.…”

Green deep‐UV photoresist based on chitosan for microelectronics

“…18,19 Polysaccharides have received a lot of interest as well. Dextrin, 20,21 cellulose, 22,23 and chitosan [24][25][26][27] may become a good alternative to the industrial resists.…”