Spin Etching as post-treatment after wafer thinning. Wafer thinning (back side grinding) is used in IC and MEMS fabrication in order to: - Achieve a desired device thickness (ICs, MEMS) - Ensure a specific thickness based on device functionality (MEMS) - Reduce substrate series resistance in vertical devices (power devices) A study by Dr. K. Gottfried of Fraunhofer ENAS on spin etching with HNO3/HF/CH3COOH on a POLOS Advanced Spin Station proved that wet etch, executed as spin etch, offered a removal of 10 μm silicon. Furthermore, it almost completely removed all traces of grinding induced substrate damage.
The platform offers a comparatively simple and reasonably priced process setup. Much faster than CMP, the process offers a high and tunable etch rate, and the ability to process backside ground wafers directly, without additional cleaning. Standard features Process applicable to 100mm, 150mm, and 200mm wafers with minimum conversion time (less than 15 minutes) Chemicals KOH HNO3/HF/CH3COOH (HNA) Continuous wafer rotation Puddle mode Dispense position and mode: Fix position Oscillating movement over a specific distance (wafer diameter) Spray dispense Flush dispense