Method for forming photomask having test patterns in blading areas
View Patent ↗A photomask and a method for forming a photomask are disclosed in which die regions that define features for a process step of a semiconductor fabrication process are formed on a photomask and a test pattern for a different process step is formed in a blading area of the photomask. Also, a method for forming test structures is disclosed in which the photomask is exposed to transfer the test pattern to a semiconductor substrate. The process step that is associated with the test pattern is then performed, forming a test structure on the semiconductor substrate. By utilizing blading areas of photomasks and including test patterns for different process steps on the same photomask, more test structures can be obtained, without the need to generate additional photomasks for testing purposes.
1. A method for forming test structures comprising:
patterning a resist layer on a first semiconductor substrate to form a resist structure within production die regions of the first semiconductor substrate, the resist layer patterned by exposing portions of a photomask that includes a plurality of identical die regions configured to a design layer of a semiconductor design and a test pattern configured to a different design layer of a semiconductor design, the identical die regions disposed in a rectangular shape that covers most of the focus region and the test pattern disposed in a blading area of the photomask, wherein all of the identical die regions are exposed and the test pattern is not exposed; and
patterning a resist layer on a second semiconductor substrate by exposing only the test pattern of the photomask to transfer the test pattern to a test die region of the second semiconductor substrate and exposing die regions from a different photomask to pattern production die regions of the second semiconductor substrate.
2. The method of claim 1 wherein patterning a resist layer on a first semiconductor substrate includes developing the resist layer on the first semiconductor substrate and patterning a resist layer on a second semiconductor substrate includes developing the resist layer on the second semiconductor substrate to form a test structure in the test die region and form different structures in the production die regions.
3. A method as recited in claim 2 further comprising:
performing a first process step on the first semiconductor substrate and performing a second process step that is different from the first process step on the second semiconductor substrate.
4. A method as recited in claim 3 wherein the second process step is a process step in a semiconductor fabrication process that forms a product, and wherein the second process step is a different process in the fabrication of the product.
5. A method as recited in claim 2 wherein the photomask includes a different test pattern formed in the blading area of the photomask, the patterning a resist layer on a second semiconductor substrate further comprising exposing the different test pattern prior to the developing the resist layer on the second semiconductor substrate to define features of an additional test die region on the second semiconductor substrate.
6. A method as recited in claim 1 wherein the photomask has a grade that is different from the grade of the different photomask.
7. A method as recited in claim 1 wherein the test pattern is configured to a design layer of a semiconductor design that forms a product that is different from the product formed by the identical die regions.
8. A method for forming test structures comprising:
patterning a resist layer on a first semiconductor substrate to form a resist structure within production die regions of the first semiconductor substrate, the resist layer patterned by exposing portions of a photomask that includes a plurality of identical die regions configured to a design layer of a semiconductor design and a test pattern configured to a different design layer of a semiconductor design, the identical die regions disposed in a rectangular shape that covers most of the focus region and the test pattern disposed in a blading area of the photomask, wherein all of the identical die regions are exposed and the test pattern is not exposed; and
patterning a resist layer on a second semiconductor substrate by exposing only the test pattern of the photomask to transfer the test pattern to a test die region of the second semiconductor substrate and exposing die regions from a different photomask to pattern other test die regions of the second semiconductor substrate.
9. A method as recited in claim 8 wherein the identical die regions form patterns in production die regions of the first semiconductor substrate, the method further comprising performing a first process step on the first semiconductor substrate and performing a second process step that is different from the first process step on the second semiconductor substrate.
10. A method as recited in claim 9 wherein the photomask includes a different test pattern that is formed in a blading area of the photomask.
11. A method as recited in claim 10 wherein the first semiconductor substrate includes only production die regions and wherein the second semiconductor substrate includes only the test die regions.
12. A method as recited in claim 9 wherein the semiconductor fabrication process forms a product, and wherein the second process step is a different process in the fabrication of a different product.
13. A method as recited in claim 8 wherein patterning a resist layer on a first semiconductor substrate includes developing the resist layer on the first semiconductor substrate and patterning a resist layer on a second semiconductor substrate includes developing the resist layer on the second semiconductor substrate to form a test structure in the test die region and form different structures in the other test die regions.
14. A method as recited in claim 8 wherein the first photomask has a grade that is different from the grade of the different photomask.
15. A method for forming test structures comprising:
patterning a resist layer on a first semiconductor substrate to form a resist structure within production die regions of the first semiconductor substrate, the resist layer patterned by exposing portions of a photomask that includes a plurality of identical die regions configured to a design layer of a semiconductor design and a test pattern configured to a different design layer of a semiconductor design, the identical die regions disposed in a rectangular shape that covers most of the focus region and the test pattern disposed in a blading area of the photomask, wherein all of the identical die regions are exposed and the test pattern is not exposed, the photoresist on the first semiconductor substrate developed to form resist structures in the production die regions; and
patterning a resist layer on a second semiconductor substrate by exposing only the test pattern of the photomask to transfer the test pattern to a test die region of the second semiconductor substrate and exposing die regions from a different photomask to pattern other die regions of the second semiconductor substrate, the resist layer on the second semiconductor substrate developed to form a test structure in the test die region and form different structures in the other die regions.
16. The method of claim 15 further comprising performing a first process step on the first semiconductor substrate and performing a second process step that is different from the first process step on the second semiconductor substrate.
17. A method as recited in claim 15 wherein the photomask has a grade that is different from the grade of the different photomask.
18. A method as recited in claim 17 wherein the photomask includes an additional test pattern formed in the blading area of the photomask.