Solar

CVD replacement coats solar cells with fewer defects, lower cost

MicroTech Systems delivered its first intelligent process station for anti-reflective coating (ARC) on solar cells. The liquid phase deposition wet process grows ARC on solar silicon wafers, replacing chemical vapor deposition for the fabrication step.

October 17, 2011 — MicroTech Systems delivered its first intelligent process station for anti-reflective coating (ARC) on solar cells. The liquid phase deposition (LPD) wet process grows ARC on solar silicon wafers, replacing chemical vapor deposition (CVD) for the fabrication step.

The LPD technology was developed by Rice University and licensed exclusively to Natcore Technology. Natcore will use the system in its thin film solar process development. The station is installed in Natcore?s R&D Center at Kodak?s Eastman Business Park, Rochester, NY.

The LPD costs less than CVD and is less environmentally harmful. Defects, like thermally induced chipping on the wafer, will be eliminated at the lower processing temperature, accommodating thinner wafers.

The intelligent process station is a fully enclosed, automated system that monitors, measures and controls coating. Substrates are pre-cleaned and temperatures stabilized prior to introduction into the deposition process. The proprietary control system manages the fluid and deposition rates and parameters. From a turbidity measurement system that manages particle generation, it has the ability to identify and eliminate contaminants from suspended matter. The intelligent process station also has a patent-pending metrology method for film measurement and control. The LPD station measures the thickness of the anti-reflective coating on a wafer while submerged in a chemical bath, altering bath composition and duration as needed. The final step in the process is surface tension gradient drying that yields substrates that are watermark-free with low particle counts and no feature damage.

The resulting films offer better conformality and reflectivity.
 
MicroTech Systems provides engineering, manufacturing and applications support for wet process and chemical distribution tools for the semiconductor, solar, MEMS, LED, Biotech and FPD industries. See www.microtechprocess.com.

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