| CPC G03F 7/70633 (2013.01) [G03F 7/70475 (2013.01); H10F 39/011 (2025.01)] | 10 Claims |
|
1. A method for measuring stitching overlay accuracy of image sensor stitching manufacturing, comprising the following steps:
step 1, forming at least two rectangular pixel areas, wherein:
at least one A-type overlay pattern mark is formed on an upper edge of each pixel area, and at least one B-type overlay pattern mark is formed on a lower edge corresponding to an upper edge, at least one A-type overlay pattern mark is formed on a left edge, and at least one B-type overlay pattern mark is formed on a right edge corresponding to the left edge;
the A-type overlay pattern mark comprises two A-type side strips and N A-type intermediate strips, N being an integer greater than 1;
the two A-type side strips and N A-type intermediate strips are arranged in parallel;
the two A-type side strips are arranged on two sides of the N A-type intermediate strips;
each of the A-type side strips is composed of a body and a head connected together;
the body is located on a side close to a pixel area center;
the head is rectangular and located on a side far away from the pixel area center;
a width of the head is greater than a width of the body;
distances from the heads of the two A-type side strips to the A-type intermediate strips adjacent to the two A-type side strips are equal;
intervals between the A-type intermediate strips are equal;
ends of the A-type intermediate strips on the side far away from the pixel area center are aligned and located between the heads of the two A-type side strips;
the B-type overlay pattern mark is configured to cooperate with the A-type overlay pattern mark and comprises two B-type side strips and N B-type intermediate strips;
the two B-type side strips and N B-type intermediate strips are arranged in parallel;
the two B-type side strips are arranged on two sides of the N B-type intermediate strips;
ends of the B-type intermediate strips on the side far away from the pixel area center are aligned;
an interval between the B-type intermediate strips is equal to one of the intervals between the A-type intermediate strips; and
distances E from the bodies of the two A-type side strips to the A-type intermediate strips adjacent to the two A-type side strips are equal to distances from the two B-type side strips to the B-type intermediate strips adjacent to the two B-type side strips;
step 2, performing left-right stitching and/or upper-lower stitching on the plurality of rectangular pixel areas, so that the A-type overlay pattern mark on an edge of two adjacent rectangular pixel areas is stitched to a corresponding B-type overlay pattern mark, wherein the heads of the two A-type side strips are in one-to-one correspondence with and stitched to ends of the two B-type side strips on the side far away from the pixel area center, with overlap areas, and the ends of the N A-type intermediate strips on the side far away from the pixel area center are in a one-to-one correspondence with and stitched to the ends of the N B-type intermediate strips on the side far away from the pixel area center, with overlap areas; and then forming a pattern after exposure; and
step 3, performing, by means of a scanning electron microscope, metrology on the A-type overlay pattern mark and B-type overlay pattern mark that are stitched together and exposed, so as to obtain a distance K from the head of one of the A-type side strips to one of the B-type intermediate strips adjacent to the A-type side strip and a distance C from the head of the other A-type side strip to the B-type intermediate strip adjacent to the A-type side strip; and according to the distances from the heads of the two A-type side strips to the B-type intermediate strips adjacent to the A-type side strips, calculating stitching overlay accuracy OVL:OVL=K−C of the two adjacent rectangular pixel areas, wherein:
when the left-right stitching is performed on the two adjacent rectangular pixel areas, OVL is overlay accuracy of the left-right stitching; and
when the upper-lower stitching is performed on the two adjacent rectangular pixel areas, OVL is overlay accuracy of the upper-lower stitching.
|