Method of inspection to determine reticle pitch

Claim 2

In the manufacture of integrated circuits on a semiconductor workpiece an improved method of inspecting to determine the degree to which a reticle in a stepper is level by determining the degree of resolution at a plurality of sites on said semiconductor workpiece including the steps comprising: providing on said reticle a plurality of sets of alignment marks having an array of blocks which are in focus at different focal lengths, said reticle having a center, said sets of alignment marks including a set of alignment marks located proximate to each of the corners of said reticle and a set of alignment marks proximate to said center of said reticle, measuring the focus at each of said sets of alignment marks with a microscope, determining the pitch of said reticle at each position of the workpiece by obtaining measurements of the focal lengths at each of said alignment marks, and checking leveling by said stepper repeatedly to obtain information for producing optimum focus of the reticle image upon the region of the workpiece being exposed.

Claim 3

A method in accordance with claim 1 wherein: said alignment marks include patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 4

A method in accordance with claim 1 wherein: said sets of alignment marks in said center three sets of alignment marks are located 66.5 mm above and below said center of said reticle, locating marks on left and right columns 52.05 mm to the right and left of said center of said reticle, with the marks on the corners of said reticle 52.05 mm above and below said center of said reticle.

Claim 5

A method in accordance with claim 1 including: each of said sets of alignment marks on said reticle having an array of blocks which are in focus at different focal lengths, and performing the step of measuring at each of said sets of alignment marks which of said blocks is in focus at each of said alignment marks.

Claim 6

A method in accordance with claim 1 including: said sets of alignment marks in said center are located 66.5 mm above and below said center of said reticle, locating sets of alignment marks on left and right columns 52.05 mm to the right and left of said center of said reticle, with the sets of alignment marks on the corners of said reticle 52.05 mm above and below said center of said reticle, and said sets of alignment alignment marks including patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 7

A method in accordance with claim 1 including: locating each of said sets of alignment marks on said reticle with an array of blocks which are in focus at different focal lengths, and performing the step of measuring at each of said sets of alignment marks which of said blocks is in focus at each of said alignment marks, locating three sets of said alignment marks in said center 66.5 mm above and below said center of said reticle, and locating three sets of said alignment marks on the left and three sets of said alignment marks on the right columns 52.05 mm to the right and left of the center of said reticle respectively, with said sets of alignment marks on said corners of said reticle 52.05 mm above and below said center of said reticle.

Claim 8

A method in accordance with claim 1 including: providing said sets of alignment marks including patterns which when in a best degree of focus provide a bright spot image in a microscope, locating said sets of alignment marks in said center 66.5 mm above and below said center of said reticle, locating said sets of alignment marks on left and right columns 52.05 mm to the right and left of the center of said reticle, with said sets of alignment marks on the corners of said reticle 52.05 mm above and below said center of said reticle, and locating said sets of alignment marks in said center 6.5 mm above and below said center of said reticle and locating the left and right columns 52.05 mm to the right and left of said center of said reticle, with the marks on said corners of said reticle 52.05 mm above and below said center of said reticle.

Claim 9

A method in accordance with claim 1 wherein: said sets of alignment marks in said center are located 66.5 mm above and below said center of said reticle, the left and right columns are located 52.05 mm to the right and left of said center of said reticle, with the sets of alignment marks on the corners of said reticle 52.05 mm above and below said center of said reticle, and each of said sets of alignment marks includes patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 10

A method in accordance with claim 1 wherein: each of said sets of alignment marks on said reticle has an array of blocks each of which is in focus at a different focal length, including the steps of: measuring at each of said sets of alignment marks which of said blocks is in focus at each of said alignment marks, and said alignment marks including alphanumeric and other patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 11

In the manufacture of integrated circuits on a semiconductor workpiece a method of inspecting to determine the degree to which a rectangular reticle with four corners and a center is level by determining the degree of resolution at a plurality of sites on said semiconductor workpiece including the steps comprising: providing at least nine sets of alignment marks on said workpiece, said nine sets of alignment marks including three horizontal rows of sets of alignment marks, said rows including a top row, a middle row and a bottom row, said top row including three sets of alignment marks comprising a first set of alignment marks proximate to the upper left corner of said reticle, a second set of alignment marks proximate to said center of said reticle along the top edge thereof and a third set of alignment marks proximate to the upper right corner of said reticle, said middle row including three sets of alignment marks comprising a first set of alignment marks proximate to the left edge of said reticle, a second set of alignment marks proximate to said center of said reticle and a third set of alignment marks proximate to the right edge of said reticle, and said bottom row including three sets of alignment marks comprising a first set of alignment marks proximate to the lower left corner of said reticle, a second set of alignment marks proximate to said center of said reticle along the bottom edge thereof and a third set of alignment marks proximate to the lower right corner of said reticle, measuring the focus at each of said sets of alignment marks, determining the pitch of said reticle at each position of the workpiece by obtaining measurements of the focal lengths at each of said alignment marks, and checking leveling repeatedly to obtain information for producing optimum focus of the reticle image upon the region of the workpiece being exposed.

Claim 12

In the manufacture of integrated circuits on a semiconductor workpiece a method of inspecting to determine the degree to which a rectangular reticle with four corners and a center is level by determining the degree of resolution at a plurality of sites on said semiconductor workpiece including the steps comprising: providing at least nine sets of alignment marks on said workpiece, said nine sets of alignment marks including three horizontal rows of sets of alignment marks, said rows including a top row, a middle row and a bottom row, said top row including three sets of alignment marks comprising a first set of alignment marks proximate to the upper left corner of said reticle, a second set of alignment marks proximate to said center of said reticle along the top edge thereof and a third set of alignment marks proximate to the upper right corner of said reticle, said middle row including three sets of alignment marks comprising a first set of alignment marks proximate to the left edge of said reticle, a second set of alignment marks proximate to said center of said reticle and a third set of alignment marks proximate to the right edge of said reticle, and said bottom row including three sets of alignment marks comprising a first set of alignment marks proximate to the lower left corner of said reticle, a second set of alignment marks proximate to said center of said reticle along the bottom edge thereof and a third set of alignment marks proximate to the lower right corner of said reticle, measuring the focus at each of said sets of alignment marks, determining the pitch of said reticle at each position of the workpiece by obtaining measurements of the focal lengths at each of said alignment marks, and checking leveling repeatedly to obtain information for producing optimum focus of the reticle image upon the region of the workpiece being exposed.

Claim 13

A method in accordance with claim 10 wherein: said alignment marks include patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 14

A method in accordance with claim 10 wherein: said marks in said center are located 66.5 mm above and below said center of said reticle, and locating marks on the left and right, 52.05 mm to the right and left of said center of said reticle, with the marks on the corners of said reticle 52.05 mm above and below said center of said reticle.

Claim 15

A method in accordance with claim 12 wherein: said alignment marks include patterns which when in a best degree of focus provide a bright spot image in a microscope, and said marks in said center are located 66.5 mm above and below said center of said reticle and locating marks 52.05 mm to the right and left of said center of said reticle, with the marks on said corners of said reticle 52.05 mm above and below said center of said reticle.

Claim 16

A method in accordance with claim 10 including: each of said sets of alignment marks on said reticle having an array of blocks which are in focus at different focal lengths, and performing the step of measuring at each of said sets of alignment marks which of said blocks is in focus at each of said alignment marks.

Claim 17

A method in accordance with claim 14 wherein: said marks in said center are located 66.5 mm above and below said center of said reticle and locating marks on the left and right, 52.05 mm to the right and left of said center of said reticle, with said marks on said corners of said reticle 52.05 mm above and below said center of said reticle.

Claim 18

A method in accordance with claim 10 including: said marks in said center are located 66.5 mm above and below said center of said reticle locating marks on the left and right, 52.05 mm to the right and left of said center of said reticle, with the marks on the corners of said reticle 52.05 mm above and below said center of said reticle, and said alignment marks including patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 19

A method in accordance with claim 10 including: locating said marks in said center are located 66.5 mm above and below said center of said reticle, and locating marks 52.05 mm to the right and left of said center of said reticle, with the marks on the corners of said reticle 52.05 mm above and below said center of said reticle, and said alignment marks include patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 20

A method in accordance with claim 10 wherein: each of said sets of alignment marks on said reticle have an array of blocks which are in focus at different focal lengths, including: measuring at each of said sets of alignment marks which of said blocks is in focus at each of said alignment marks, and said alignment marks including alphanumeric and other patterns which when in a best degree of focus provide a bright spot image in a microscope.

Claim 21

A method in accordance with claim 10 wherein: said alignment marks include patterns which when in a best degree of focus provide a bright spot image in a microscope.