Influence of operation parameters on BOSCH-process technological characteristics

Abstract

Authors investigated direct plasmachemical etching of silicon with Bosch-process using installation for inductively coupled plasma (PLATRAN-100) in gas area consist of SF6 and CHF3 gases in etching and deposition steps respectively. Defined correlations of etching rate, selectivity Si/photoresist, anisotropy, etch uniformity and sidewall angle on flow rate of polymerizing gas and electrical bias on deposition step. It is shown that increasing of CHF3 flow rate leads to higher etch selectivity Si/photoresist, anisotropy and uniformity of silicon but increase etching rate and sidewall angle. Also there was demonstrated that increasing of electrical bias on deposition step leads to higher silicon etching rate, uniformity and sidewall angle but at the same time decrease anisotropy and selectivity Si/photoresist. Authors reached etch selectivity Si/photoresist about 38 with etch uniformity 99.3% and depth about 18 mkm. The highest speed of silicon etch was 3.12 μm/min with uniformaty 99.7% and sidewall angle 89.6 °.