Forming a bridging feature using chromeless phase-shift lithography
View Patent ↗An elongated, chromeless, bridging feature is formed on a photolithography mask with an etching depth that causes a nominal phase difference of more than 180 degrees to energy passing through the photolithography mask. A corresponding photoresist feature is formed using the bridging feature. The phase difference may be chosen to minimize dimensional variation of the corresponding photoresist feature.
1. A method comprising:
forming an elongated, chromeless, bridging feature on a photolithography mask with an etching depth that causes a nominal phase difference of more than 180 degrees to energy passing through the photolithography mask; and
forming a corresponding photoresist feature using the bridging feature.
2. The method of claim 1 , wherein the phase difference is chosen to minimize dimensional variation of the corresponding photoresist feature.
3. The method of claim 1 , wherein the phase difference is chosen to minimize span bending of the corresponding photoresist feature.
4. The method of claim 1 , wherein the nominal phase difference is between 180 and 190 degrees.
5. The method of claim 1 , further comprising forming first and second anchor features on the photolithography mask, wherein the bridging feature extends between the first and second anchor features.
6. The method of claim 5 , wherein the first and second anchor features are formed using a combination of phase shift etch and opaque overlay on the photolithography mask.
7. The method of claim 1 , wherein a span of the corresponding photoresist feature is at least ten times greater than a width of the corresponding photoresist feature.
8. The method of claim 7 , wherein the width of the corresponding photoresist feature is between 30 nm and 50 nm.
9. The method of claim 1 , wherein a region of interest of the corresponding photoresist feature is used to form a feature of a read/write head.
10. A photolithography mask, comprising:
an elongated, chromeless, bridging feature with an etching depth that causes a nominal phase difference of more than 180 degrees to energy passing through the photolithography mask, the energy forming a corresponding photoresist feature based on the bridging feature.
11. The photolithography mask of claim 10 , wherein the phase difference is chosen to minimize dimensional variation of the corresponding photoresist feature.
12. The photolithography mask of claim 10 , wherein the phase difference is chosen to minimize span bending of the corresponding photoresist feature.
13. The photolithography mask of claim 10 , wherein the nominal phase difference is between 180 and 190 degrees.
14. The photolithography mask of claim 10 , further comprising first and second anchor features, wherein the bridging feature extends between the first and second anchor features.
15. The photolithography mask of claim 14 , wherein the first and second anchor features are formed using a combination of phase shift etch and opaque overlay on the photolithography mask.
16. The photolithography mask of claim 10 , wherein a span of the corresponding photoresist feature is at least ten times greater than a width of the corresponding photoresist feature.
17. The photolithography mask of claim 16 , wherein the width of the corresponding photoresist feature is between 30 nm and 50 nm.
18. The photolithography mask of claim 10 , wherein a region of interest of the corresponding photoresist feature is used to form a feature of a read/write head.