February 2004

Glass Micromachines

Computer-guided laser beams create microscopic 3-D structures.

By Technology Review

From labs-on-a-chip that mix tiny amounts of fluids in biomedical assays to the miniature radios envisioned for future cell phones, a growing number of devices require microscopic parts. More-complex parts are usually made, layer by layer, atop wafers of silicon. Now Invenios, a startup in Santa Barbara, CA, is experimenting with a faster, cheaper process that can create 3-D shapes as small as a cubic micrometer with a single pass of a laser. The technique, invented at Aerospace, an El Segundo, CA-based defense contractor, starts with a special kind of glass whose atoms are in a jumbled, unordered state. Guided by computer-aided-design files, a laser beam strikes certain areas inside the glass, displacing the atoms' electrons. Then, when heated, the treated parts of the glass form ordered, crystalline structures. The crystalline material is etched away by acid, leaving behind glass structures such as tiny turbines, microfluidic valves, or optical waveguides for fiber-optic systems. Thousands of millimeter-scale components could fit on a single wafer and could cost as little as 30 cents each in volume.