Laser enhanced etching in KOH

We have used a focused laser beam to perform localized etching on 〈111〉 Si and several ceramic materials submerged in an aqueous potassium hydroxide solution. The etching process is accompanied by localized melting of the material whenever high material removal rates are observed. Mil sized blind holes, through holes, and slots have been fabricated. Instantaneous etch rates as high as 200 μm/s have been observed in alumina/TiC ceramic for 1-W of incident laser power (∼106 W/cm2). An average rate of a 15 μm/s has been observed in the etching of through holes in 10-mil silicon with 15 W of incident laser power (∼107 W/cm 2).