Negative Pattern Formation in Positive Resist Layer by EB / UV Hybrid Lithography

Abstract

By the combination of EB (electron beam) pattern irradiation and UV (ultraviolet) exposure processes, negative tone pattern can be formed in a positive type resist film. It is well known that a novolac resin based resist film can be crosslinked by thermal and EB irradiation processes. By changing the EB irradiation and UV light exposure doses, a dissolution resistance of the resist film to TMAH (tetramethylammoniumhydroxide) alkaline aqueous solution can be controlled. As the result, the EB/UV hybrid lithography is effective for the fabrication of difference height patterns in a single resist layer. A dose response characteristic of a resist film is determined. A roughness of resist pattern in EB/UV hybrid lithography is also discussed. As an application, a micro square vessel array is fabricated used for a bioelectronic field Keywords: electron beam lithography, photolithography, photoresist, atomic force microscopy (AFM), surface roughness, EB/UV hybrid lithography

Organic–Inorganic Hybrid Thermoset-Based Dual Tone-Type Photosensitive Material

“…In recent years, dual tone-type photosensitive materials that can be used to form both positive and negative tone-type patterns have attracted attention since they are potentially useful for the formation of fine and complex patterns in a wide range of applications. So far, examples of dual tone-type pattern formation have been reported utilizing solubility or reactivity switching based on changes of developers, − light sources, irradiation dose, − or post-exposure bake (PEB) conditions . Preparation of dual tone-type patterns using different developers or light sources needs special or additional equipment installation, while the switch of the irradiation dose or PEB condition requires careful UV or temperature control, all of which are not so useful in practical application in terms of cost and productivity.…”

Etching process of narrow wire and application to tunable-barrier electron pump

“…The main point is that the patterning of the wet-etching process is performed by only using a positive photoresist S1813G (Shipley), which has a strong resistance against acid. Some positive photo resists work as a negative EB resist 21 . We perform EB lithography followed by photolithography after the coating of this photo resist.…”