Patent ID: 7782441

Claim:
An alignment method of mask patterns in patterning processes, including forming a first layer by transferring a first mask pattern onto a wafer or a layer formed on the wafer, and forming a second layer by transferring a second mask pattern onto said first layer, said method comprising: a first alignment step of performing, when forming said first layer, alignment for minimizing offset between a center position of said wafer and a center position of said first mask pattern and a residual rotation error between said wafer and said first mask pattern, and additional alignment for compensating an amount of possible deviation of superposition of said second layer pattern on said first layer pattern, said possible deviation being caused by linear expansion and contraction of a wafer and caused by an orthogonal error between a wafer and a mask pattern, said deviation being obtained by measuring in advance in patterning processes successively performed for a plurality of wafers; and a second alignment step of performing, when forming said second layer, only alignment for minimizing offset between a center position of said first layer pattern and a center position of said second mask pattern and a residual rotation error between said first layer pattern and said second mask pattern.