Gibb & Riley, LLC
Sidewall spacer pattern formation method
Disclosed are methods of using a lithography-lithography-etch (LLE) technique to form a sidewall spacer pattern for patterning a target layer. In the methods, a photoresist layer is patterned by performing multiple lithographic processes with different photomasks, including a first photomask with a first pattern of parallel bars separated by spaces and a second photomask with a second pattern of opening(s) oriented in an essentially perpendicular direction as compared to the bar(s). The photoresist layer is then developed, creating a third pattern. The third pattern is transferred into a mandrel layer below to form mandrels of different lengths. Then, sidewall spacers are formed on the mandrels and the mandrels are selectively removed to form the sidewall spacer pattern. This sidewall spacer pattern is subsequently used in a sidewall image transfer (SIT) process to pattern a target layer below.
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Lei Ruilong Yulu Xunyuan
Sun Xie Chen Zhang