Optimization for etching shallow ridge and trench profiles on silicon based on continuous etching process in ICPRIE system

In order to directly characterize sidewall roughnesses of shallow microstructures with etching depth less than 10 μm using a conventional atomic force microscope tip, an easy bevel-cut sample technique was developed. With help of the proposed measurement technique, the sidewall verticalities and roughnesses between trench and ridge profiles were compared and optimized using an L9 orthogonal array experiment based on a simple continuous dry-etching process. Additionally, due to the influence of loading effect, the contribution proportions of four control factors on etching quality characteristics were evaluated. As some improved measurement results, optimized root mean square sidewall roughnesses of 3.61 and 4.7 nm were obtained for ridge and trench structures, respectively, with depth greater than 4 μm and the sidewall verticality of 90 ± 1°.