Patent ID: 6953733

Claim:
A method of aligning a substrate, comprising: providing a semiconductor substrate having an upper layer and an alignment mark structure formed on a surface region of the upper layer, the surface region defined by opposite first and second parallel sides extending along the upper layer, wherein the alignment mark structure comprises (a) a first outer side wall extending upwardly from the upper layer and extending lengthwise along the first parallel side of the surface region, wherein the first outer side wall is defined lengthwise by alternating first and second wall portions, wherein each of the first wall portions is spaced farther from the first parallel side of the surface region than each of the second wall portions, (b) a second outer side wall extending upwardly from the upper layer and extending lengthwise along the second parallel side of the surface region, wherein the second outer side wall is defined lengthwise by alternating third and fourth wall portions, wherein each of the third wall portions is spaced farther from the second parallel side of the surface region than each of the fourth wall portions, and (c) an alignment pattern defined by openings in the alignment mark structure located between the first and second outer side walls; imaging the alignment mark structure to extract an image data indicative of at least a portion of the alignment pattern and portions of the first and second wall portions of the first outer side wall; and aligning the substrate based on the image data.