Wafer Thinning Solution for Wafer-Level-Capped MEMS Devices

A wafer backgrinding solution is demonstrated to successfully thin wafer-level-capped MEMS accelerometers down to 250mum thickness. Capped MEMS wafers are prepared for manufacturing by using wafer protective tapes. Holes are punched on layers of tape, matching the thickness of the caps, that serve as gap fills in-between caps and through the wafer edge. The capped wafers are fully supported while processing using standard backgrinding machines. Manufacturing issues and corresponding fixes to attain satisfactory result are also discussed. The thinned capped accelerometer device is packaged in a 4times4mm leadframe chip scale package (LFCSP) to check its performance