Maskless Lithography Brings Gene Chips to Labs

Scientists at the University of Wisconsin in Madison have developed an etching process for gene chips that eliminates the need for stencillike masks. The technique, dubbed MAS for maskless array synthesizer, promises to allow any laboratory to make its own chips at a fraction of the current cost and in less time.

Gene chip technology enables researchers to deconstruct and analyze thousands of segments of DNA simultaneously. Affymetrix Inc. of Santa Clara, Calif., produces all of the chips with an ultraviolet photolithography process that requires each silicon chip to be masked with a UV-opaque material that is customized to the desired application. As many as 100 masks are used to etch a single, disposable chip, which costs $2500 to $12,000.

The university team's approach incorporates digital light processing technology from Texas Instruments Inc.'s Digital Imaging Div. in Plano, Texas. An array of 480,000 aluminum mirrors on a computer chip focuses the light onto the chip in the required patterns.