Deep UV pattern definition in PMMA

Abstract

We have patterned polymethyl methacrylate (PMMA) resist by exposing it to the fifth harmonic (213 nm) of an Nd:YAG source through metalized apertures in contact with the resist. Interference patterns with both near- and far-field origins were observed. In order to test the contrast and uniformity of exposure, we deposited germanium onto developed areas to form arrays with feature sizes of ∼200 nm. We present a straightforward model for interference effects generated in our process, and discuss opportunities for direct-write lithography through single apertures.

Solvent effects on the thermal and mechanical properties of poly(methyl methacrylate) casted from concentrated solutions

“…PMMA is a thermoplastic polymer commonly employed as the main component of positive resists for both electron and UV photolithography,6,7 as well as an imprintable material for hot‐embossing soft lithography 8. Because of its excellent transparency in the visible spectrum, PMMA is widely used in optical applications, especially as a matrix for nonlinear optical composite materials 9,10…”

Stage-for-stage comparison of definitive chemoradiotherapy, surgery alone and neoadjuvant chemotherapy for oesophageal carcinoma

“…As shown schematically in Figure 4 a, we also deposited a dilute aqueous solution (0.05 mg mL −1 ) of the well‐dispersed graphene nanosheets3c onto a silicon substrate by spin‐coating (see Figure 2). Individual graphene sheets on the substrate were then covered by PMMA micropatterns photolithographically produced according to a previously reported method9 (see also the Supporting Information). Because of the random distribution of the graphene sheets on the substrate surface, one can anticipate that some graphene sheets may be partially masked by the PMMA micropatterns (step 1, Figure 4 a).…”

Recent progress in direct patterning technologies based on nano-imprint lithography

“…In the semiconductor industry, the capability of fabricating precisely aligned nano-patterns with high resolution is very significant for producing highly integrated circuits and smaller transistors. Deep-UV photolithography [1][2][3] has been optimized for the semiconductor industry as a main patterning technology. However, it is difficult to adopt photolithography for various next-generation electronic devices due to its high process cost, complex process steps and limitation on the use of substrates.…”