Research on wafer-level SiC microgroove array process via integrated molding-etching process

Abstract

Silicon carbide (SiC) microgroove arrays (MGAs) play a pivotal role as optical components in modern optical engineering. This paper introduces an innovative approach for the fabrication of MGAs on hard materials. This method integrates hot embossing (HE) and inductively coupled plasma (ICP), utilizing polydimethylsiloxane (PDMS) as the intermediary mold due to its excellent demolding performance and shape replication qualities. The process involves transferring the MGAs from the Ni-P master mold to the PDMS mold, followed by replication onto the photoresist surface by hot embossing. Subsequently, the MGAs on the photoresist mask is etched into the hard substrate material using ICP etching. For efficient customization of MGAs, a reliable geometrical model based on angular dependence theory is developed to assist in selecting process parameters and designing masks. The correlation between etching selectivity and characteristic dimension is elucidated. Experimental results demonstrate that the sidewall angle decreases with higher selectivity and increases with a greater sidewall angle on the patterned mask. Plasma etching reveals unaffected areas in convex corners and the forming errors in concave corners, highlighting a high angular dependence of the etch rate. Moreover, minimizing microdefects can be achieved by optimizing process parameters and reducing etch time.