Highly-corrected mask
View Patent ↗The present invention discloses a pattern-distributed mask. It comprises a plurality of mask regions whose images will be merged into a single image (e.g. by interleaving) on an image-carrier (e.g. wafer, mask blank). The pattern spacing on a pattern-distributed mask could be much larger than a conventional mask. For example, all pattern spacing on a pattern-distributed mask could be ˜3F (vs. ˜1F on a conventional mask). It can enable highly-corrected mask, as well as thin-film mask with supporting structures.
1. A highly-corrected mask comprising a plurality of pattern structures, each of said pattern structures comprising:
a zero-order structure having a minimum feature size;
at least one higher-order correctional structure surrounding at least a portion of said zero-order structure;
wherein there exists at least one point at the outer edge of said higher-order correctional structure whose smallest spacing to the outer edge of said zero-order structure is larger than half of said minimum feature size;
whereby the optical image formed by said zero-order structure and said higher-order correctional structure is smaller than the optical image formed by said zero-order structure alone.
2. The highly-corrected mask according to claim 1 , wherein said higher-order correctional structure is a phase-shifter.
3. The highly-corrected mask according to claim 1 , wherein said higher-order correctional structure is a correctional ring separated from said first-order pattern by a spacer structure.
4. The highly-corrected mask according to claim 3 , wherein said correctional ring is a clear pattern.
5. The highly-corrected mask according to claim 3 , wherein said spacer structure is a dark pattern.
6. The highly-corrected mask according to claim 3 , wherein said spacer structure is a phase-shifter.
7. The highly-corrected mask according to claim 3 , wherein said spacer structure is a trench.
8. The highly-corrected mask according to claim 1 , wherein said pattern structures are vias.
9. The highly-corrected mask according to claim 1 , wherein said pattern structures are lines.
10. A highly-corrected mask system, comprising:
a first mask region comprising a plurality of pattern structures; and
a separate second mask region comprising a plurality of pattern structures;
each of said pattern structures comprising:
a zero-order structure having a minimum feature size;
at least one higher-order correctional structure surrounding at least a portion of said zero-order structure;
wherein there exists at least one point at the outer edge of said higher-order correctional structure whose smallest spacing to the outer edge of said zero-order structure is larger than half of said minimum feature size;
whereby the optical image formed by said zero-order structure and said higher-order correctional structure is smaller than the optical image formed by said zero-order structure alone;
a litho-tool for interleaving the optical images from said first and second mask regions on an image carrier.
11. The highly-corrected mask system according to claim 10 , wherein said first and second mask regions are located on a same mask.
12. The highly-corrected mask system according to claim 11 , wherein said litho-tool can move said mask in a controlled manner.
13. The highly-corrected mask system according to claim 10 , wherein said higher-order correctional structure is a phase-shifter.
14. The highly-corrected mask system according to claim 10 , wherein said higher-order correctional structure is a correctional ring separated from said first-order pattern by a spacer structure.
15. The highly-corrected mask system according to claim 14 , wherein said correctional ring is a clear pattern.
16. The highly-corrected mask system according to claim 14 , wherein said spacer structure is a dark pattern.
17. The highly-corrected mask system according to claim 14 , wherein said spacer structure is a phase-shifter.
18. The highly-corrected mask system according to claim 14 , wherein said spacer structure is a trench.
19. The highly-corrected mask system according to claim 10 , wherein said pattern structures are vias.
20. The highly-corrected mask system according to claim 10 , wherein said pattern structures are lines.