Study on Quartz Multitier Mold Fabrication Using Gray Scale Laser Beam Lithography

Abstract

Gray scale laser beam lithography (G-LBL) is an inexpensive, fast, and simple process for creating a multitier or near-continuous surface topography of microscale components. In this work, the combined use of the microfabrication processes of G-LBL (with a 375 nm diode laser) and reactive ion etching (RIE) was studied to fabricate multitier quartz molds. In the G-LBL process, both pixel pulse length and grayscale level in bitmap images were controlled under a fixed laser power of 10 mW to develop multitier features in an OFPR-800LB resist in a single writing step. By the subsequent CHF3 RIE process, the multitier features defined in the resist were transferred into the underlying quartz with a depth ratio of 1:2.2. Furthermore, the feasibility of the fabricated quartz molds was verified through the UV imprint experiments.