Method of characterizing linewidth errors in a scanning lithography system
First Claim
1. A method of characterizing linewidth errors in a lithography system used to delineate a desired pattern onto an exposure site of a wafer, said method comprising the steps of:
- providing a reticle having a pattern;
delineating the pattern onto an exposure site of a wafer by projecting a slit of light extending in a slit direction y through the reticle while scanning the reticle and the wafer in a scanning direction x relative to the lens;
conceptually dividing the exposure site into a grid having one series of lines extending in the scan direction x and another series of lines extending in the slit direction y whereby points corresponding to intersections of the lines may each be assigned a pair of coordinates (x,y);
measuring linewidths of the portion of the pattern at each of the points (x,y);
generating a linewidth error value ERROR (x,y) for each of the points (x,y);
calculating an ERRORoptical (y) value for each y coordinate by averaging the ERROR (x,y) values for each group of points (x,y) having a common y coordinate to determine the contribution of optical aberrations to linewidth errors.
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Abstract
A method of characterizing linewidth errors in a lithography system 30 used to delineate a desired pattern onto an exposure site of a wafer 32. The pattern of a reticle 34 is transferred onto an exposure site 56 of a wafer 32 by projecting a slit of light extending in a slit direction y through the reticle while scanning the reticle and the wafer in a scanning direction x relative to the lens. The exposure site 56 is conceptually divided into a grid having one series of lines extending in the scan direction x and another series of lines extending in the slit direction y whereby points corresponding to perpendicular intersections of the lines may each be assigned a pair of coordinates (x,y). The linewidths of the pattern are measured for each of the points (x,y) and a linewidth error value ERROR (x,y) is generated for each of the points (x,y). An ERRORoptical (y) value for each y coordinate is calculated by averaging the ERROR (x,y) values for each group of points (x,y) having a common y coordinate. In this manner, the contribution of optical aberrations to linewidth errors may be determined.
28 Citations
20 Claims
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1. A method of characterizing linewidth errors in a lithography system used to delineate a desired pattern onto an exposure site of a wafer, said method comprising the steps of:
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providing a reticle having a pattern; delineating the pattern onto an exposure site of a wafer by projecting a slit of light extending in a slit direction y through the reticle while scanning the reticle and the wafer in a scanning direction x relative to the lens; conceptually dividing the exposure site into a grid having one series of lines extending in the scan direction x and another series of lines extending in the slit direction y whereby points corresponding to intersections of the lines may each be assigned a pair of coordinates (x,y); measuring linewidths of the portion of the pattern at each of the points (x,y); generating a linewidth error value ERROR (x,y) for each of the points (x,y); calculating an ERRORoptical (y) value for each y coordinate by averaging the ERROR (x,y) values for each group of points (x,y) having a common y coordinate to determine the contribution of optical aberrations to linewidth errors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification