A systematic study of dry etch process for profile control of silicon tips

Control of silicon tip profile is desirable in many applications. Although there are many parameters that have influence on the final tip profile, the study reported in this paper is concentrated on the effect of adding CHF3, O2 and Ar gases to the normal SF6 reactive etching process. With fixed R.F. power, total pressure and SF6 flow rate, addition of these gases has been found to have significant influence on tip profile, including tip size, height and apex radius. A particular shape of silicon tips can be achieved by fine tuning the flow rate of these added gases in combination with the tuning of other process parameters. Comparing with other processes, our technique is more simplified and is capable of manufacturing sharp tips with a larger variety of shapes.