| 摘要 |
An alignment method of mask patterns in patterning processes includes 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 the first layer. The method particularly includes a first alignment step of performing, when forming the first layer, alignment for minimizing offset between a center position of the wafer and a center position of the first mask pattern and a residual rotation error between the wafer and the first mask pattern, and alignment based on an amount of deviation of superposition of the second layer pattern on the first layer pattern. The deviation is caused by linear expansion and contraction of a wafer and caused by an orthogonal error between a wafer and a mask pattern, and also the deviation is obtained by measuring in advance in pattering processes successively performed for a plurality of wafers. The method also includes a second alignment step of performing, when forming the second layer, only alignment for minimizing offset between a center position of the first layer pattern and a center position of the second mask pattern and a residual rotation error between the first layer pattern and the second mask pattern.
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