ESC’s Influence To Production In Poly ETCH And Methods To Improve ESC’s Lifetime

In the modern VLSI manufacturing, ESC has been widely used in ETCH, CVD process for its good heat transfer, uniformity control, and low defect production. Besides chucking wafer and cooling wafer, ESC also can impact etching profile. In poly etch application, higher chucking voltage is proven to result in notching phenomena which can cause yield loss. Decrease chucking voltage can solve this problem, and improve yield.TCP9400 bipolar ESC has two electrodes, and can induce two polar charges within wafer. Without DC bias, the quantity of the two charges is equal, and chucking force is equal. But applying DC bias, chucking force of the two electrodes will be different, which may cause chucking failure. A dynamic compensate voltage is required. To ensure this voltage accurate is very important for product quality control.Monitoring parameters of ESC_CURRENT_LEAK, Gas₀9_Flow_In is used to guard weather ESC is working under reliable status, avoid product scraping.WAC is developed to keep chamber condition the same between wafer and wafer. Chamber can auto run a clean recipe without dummy wafer every production wafer. Fine tune WAC recipe and improve some usage methods can significant extend ESC lifetime.