Blasted away

Abrasive etching is an economical way to precision machine ceramics and other brittle materials. The Photo-Machining Process from Ikonics Corp., Duluth Minn., simultaneously etched 0.012-in.-diameter thru-holes in a thin silicon wafer in about 15 min. Laser drilling could take hours depending on the type of laser and wafer thickness. PMP can remove material at a rate much faster than conventional machining methods and is best suited for symmetrical flat or cylindrical substrates. For through-holes in thicker materials, etching can take place from both sides to help straighten sidewalls. This may produce an hourglass effect, which may help certain applications. An example of an etched glass substrate shows the taper effect of deep etching. This was etched to 1/4-in. depth. Quartz/glass etches quickly and this part was done within 5 min. Texturing roughens surfaces for subsequent operations such as an adhesive application. Until recently the only way to put precision features on brittle substrates