CPC G03F 7/70633 (2013.01) [G01N 21/4785 (2013.01); G01N 21/4788 (2013.01); G01N 21/9501 (2013.01); G03F 7/70625 (2013.01)] | 12 Claims |
1. A target comprising:
a first periodic structure formed on a first layer of a semiconductor device, wherein each of a plurality of gratings in the first periodic structure has a first width along a first axis and a first height along a second axis, wherein the first periodic structure has a first pitch;
a second periodic structure formed on a second layer of the semiconductor device, wherein each of a plurality of gratings in the second periodic structure has a second width along the first axis and a second height along the second axis, wherein the second width is narrower than the first width, wherein the second periodic structure has a second pitch less than the first pitch, and wherein the gratings of the first periodic structure are positioned to overlap with the gratings of the second periodic structure, wherein the second periodic structure extends beyond the first periodic structure along the first axis, and wherein the first periodic structure and the second periodic structure are in a first array;
a second array of the first periodic structure and a second of the second periodic structure, wherein the second periodic structure in the second array extends beyond the first periodic structure in a direction along the second axis from that of the first array; and
a third array of the first periodic structure and a third and fourth array of the second periodic structure, wherein the first height is longer than the second height, and wherein the gratings of the first periodic structure in the third array extend over the third and fourth arrays of the second periodic structure along the second axis;
wherein the first periodic structure and the second periodic structure provide electron beam overlay measurements and scatterometry overlay measurements.
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