Etch selectivity. C bonds with oxygen at the surface F bonds with Si. BOSCH Patent STS, Alcatel, Trion, Oxford Instruments Mar 31, 2020 · Wet etching is often chosen for its selectivity. The addition of H2 removes F from the system by forming stable HF gas. Many wet etches are very selective to different materials. • What is dry etching? – Material removal reactions occur in the gas phase. Adding O2 can increase etch rate and increases selectivity over oxide. High F/C ratio favors etching. Aug 5, 2020 · Learn what etch selectivity is, how it is measured, and why it is important for various applications. 6 Selectivity Selectivity is a critical etch parameter which refers to the relative etch rate of the film to be etched to the etch rate of another material exposed to the etchant. Find out the difference between selective and non-selective etching, and what high and low selectivity mean. A high selectivity allows thinner masks, and the ability to stop etching abruptly on the layer beneath the layer being etched. • Why dry etching? • Development of dry etching • Plasma parameters/influences. See examples of wet and dry etching, isotropic and anisotropic etching, and etch rates and conditions. C3 and F radicals adsorb. Learn about etching techniques, selectivity, and materials in microfabrication. . By-products are CO, CO2, COF2, SiF4. Since the E-field is perpendicular to the wafer surface, minimal fluorocarbon etching of sidewalls occurs while deposition on the flat portions of the wafer are easily removed. 2. 2. gkmubrc zjg sufi gcts srsy wfu mblb yun hxyb svcdt