Patent ID: 8916475

Claim:
A patterning method, comprising: sequentially forming a mask composite layer and a first tri-layer photoresist on a target layer, wherein the mask composite layer comprises, from bottom to top, an amorphous carbon layer, a first mask layer and a second mask layer, and an etching selectivity of the second mask layer is different from an etching selectivity of the first mask layer; performing a first etching process to the mask composite layer by using the first tri-layer photoresist as a mask, so as to form at least one first opening pattern in the second mask layer of the mask composite layer; removing the first tri-layer photoresist; forming a second tri-layer photoresist on the mask composite layer; performing a second etching process to the mask composite layer by using the second tri-layer photoresist as a mask, so as to form at least one second opening pattern in the second mask layer of the mask composite layer; removing the second tri-layer photoresist; patterning the amorphous carbon layer and the first mask layer by using the second mask layer as a mask, so as to form a patterned mask composite layer; and patterning the target layer by using the patterned mask composite layer as a mask.