Sample for coordinates calibration and method for fabricating the same
View Patent ↗A sample for coordinates calibration including (1) a substrate having a circular plate-shape, and (2) multiple intentional defects that form a grid pattern with squares as unit grids on a surface of the substrate, the intentional defect providing a center point of the grid pattern coinciding with a center point of the substrate and, letting the maximum value of a number of the unit grids arranged from the center point of the substrate in radial directions be N (a natural number equal to or larger than two), a number of the intentional defects formed at equal spaces along one side of the unit grid being N+1 including the two intentional defects providing a vertex of the unit grid is proposed.
1. A wafer for coordinates calibration comprising:
multiple unit exposure areas having multiple intentional defects that form a grid pattern with squares as unit grids on a surface of the wafer, the multiple intentional defects providing a center point of the grid pattern coinciding with a center point of the wafer,
wherein, when a maximum value of a number of the multiple unit exposure areas arranged from a coordinate origin in a radial direction is M (a natural number equal to or larger than two), the number of intentional defects in the multiple unit exposure areas forming each of two respective grid lines that intersect in a cross form and including the center point is M−1, and a distance between two adjacent intentional defects is 1/(M−1).
2. The wafer for coordinates calibration according to claim 1 , wherein the wafer for coordinates calibration is used for a coordinates calibration of a surface inspection apparatus that manages coordinates of the wafer in an r-theta coordinate system.
3. The wafer for coordinates calibration according to claim 1 , wherein the intentional defect is formed by a material having stiffness to light in a wavelength band in an ultraviolet region, deep ultraviolet region and/or extreme ultraviolet region.
4. The wafer for coordinates calibration according to claim 1 , wherein the intentional defect has a projection shape.
5. The wafer for coordinates calibration according to claim 1 , wherein the intentional defect has a circular cylinder shape or semi-spherical shape.
6. The wafer for coordinates calibration according to claim 1 , wherein the intentional defect is fabricated by a semiconductor process including exposure and etching.
7. The wafer for coordinates calibration according to claim 1 ,
wherein, when a maximum value of a number of the unit grids arranged from the center point of the substrate in radial directions is N (a natural number equal to or larger than two), a number of the intentional defects formed at equal spaces along one side of the unit grid is N+1 including two intentional defects providing a vertex of the unit grid.
8. A method for fabricating a sample for coordinates calibration comprising the steps of:
coating a surface of a substrate having a circular plate-shape with a resist;
sequentially transferring unit exposure patterns on a surface of the resist by multiple exposure steps, letting a maximum value of a number of the unit exposure patterns arranged in radial directions including the unit exposure pattern used for formation of a center point of a grid pattern to be formed on the surface of the resist is M (a natural number equal to or larger than two), the unit exposure pattern having M−1 defect patterns forming a first grid line and M−1 defect patterns forming a second grid line that intersects with the first grid line in a cross form, and the defect pattern in common with the first and second grid lines providing a center of the unit exposure pattern and a space between two defect patterns adjacent on each grid line given by 1/(M−1)th of one side of the exposure pattern; and
forming multiple intentional defects in the surface of the substrate by etching the surface of the substrate using a pattern formed using the exposed resist as a mask.
9. The method for fabricating the sample for coordinates calibration according to claim 8 , wherein the multiple intentional defects are for formation of a grid pattern with squares as unit grids on a surface of the substrate and the intentional defect providing the center of the grid pattern coincides with a center point of the substrate, and, letting the maximum value of a number of the unit grids laid out from the center point of the substrate in radial directions be N (a natural number), a number of the intentional defects formed at equal spaces along one side of the unit grid is N+1 including the two intentional defects providing a vertex of the unit grid.
10. The method for fabricating the sample for coordinates calibration according to claim 8 , wherein the intentional defect is formed by a material having stiffness to light in a wavelength band in an ultraviolet region, deep ultraviolet region and/or extreme ultraviolet region.
11. The method for fabricating the sample for coordinates calibration according to claim 8 , wherein the intentional defect has a projection shape.
12. The method for fabricating the sample for coordinates calibration according to claim 8 , wherein the intentional defect has a circular cylinder shape or semi-spherical shape.