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In a variety of power devices , Trench MOSFET ( a new vertical structure of the device ) , a low on-resistance , low gate-drain charge density , and low switching losses , high speed switching components . A Trench MOS A special process structure by increasing the gate conductor area , further to reduce the on-resistance , reduce the switching power consumption and increase the switching speed . However, the conventional semiconductor technology can not meet the new Trench MOS Product A target yield hindered its widespread application . The project addresses the problem of low yield (low yield) of the product , the lithography process improvements to improve its yield . Trench MOS Product A process through a series of experiments , the mechanism of the low yield analysis , in particular, affect the parameters of the photolithographic developing process analysis . Through the rational design of experiments to validate reduce Breath developing process ultrapure water can improve yields, and to assess its impact on the development process , come to the feasibility study of this process . Then developing processes to reduce the technology of ultra - pure water shoot out time which applied to actual production , production results derived through mass production data to assess the effect of this process improvement . The results show that this method can eliminate the photolithography process of the P-well after developing the electrostatic charge accumulated in the surface of the wafer , reducing the uniformity of the influence on the P-well ion implantation , to eliminate the drift of the threshold voltage Vth , to improve the yield to the target value . In addition , this method also can improve the product flux throughput .
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