Systems and methods for using double mask techniques to achieve very small features
View Patent ↗System and methods are provided for the manufacture of a magnetic write head including a pole and yoke region, and a nose shape transition region connecting the yoke to the pole having very small minimum radius of curvature, providing for a sharp transition. A double mask technique is used providing for the adjustment of an offset and illumination conditions between the first and second mask, which provides the capability of tuning the shape of the transition region, and achieving features that would otherwise not be achievable due to distortions caused by optical proximity effect.
1. A method of taking advantage of the optical proximity effects in the fabrication of thin film heads (TFH) including small features, the method comprising:
providing at least a first and second photolithography masks (mask) corresponding to a desired shape, wherein each of the first and the second masks includes one critical feature of the desired shape; and
sequentially exposing a photoresist layer covering an area corresponding to the desired shape using the at least first and second masks.
2. The method of claim 1 further comprising:
adjusting an offset between the at least first and second masks to modify features of the desired shape.
3. The method of claim 1 wherein a decrease in the offset increases the sharpness of the desired shape.
4. The method of claim 1 further comprising:
exposing the photoresist layer through the first mask with a first set of illumination conditions and exposing the photoresist layer through the second mask with a second set of illumination conditions.
5. The method of claim 4 wherein the first and the second set of illumination conditions are the same.
6. The method of claim 4 wherein the first and the second set of illumination conditions are different.
7. The method of claim 1 , wherein the desired shape forms a transition from a yoke region to a main pole region in a magnetic writer.
8. The method of claim 7 , wherein the desired shape is a partial circular shape with a minimum radius of less than 100 nm.
9. The method of claim 7 , wherein the desired shape is a partial circular shape with a minimum radius of less than 80 nm.
10. The method of claim 1 wherein the first mask has a T shape.
11. The method of claim 10 wherein the width of an upper rectangle of the T shape is between 1 micron to 0.5 microns and the width of the lower rectangle is between 200 nm to 500 nm.
12. The method of claim 1 , wherein the second mask has a funnel shape.
13. The method of claim 1 , wherein the width of the upper part of the funnel is between 2.5 microns to 1 micron and the width of the lower part of the funnel is between 400 nm to 700 nm.
14. The method of claim 1 wherein the illumination conditions parameters include the light shape, intensity, exposure time and aperture.
15. The method of claim 14 , wherein the aperture includes quasar aperture, annular aperture and circular aperture.
16. A method of using a double mask technique for optimizing a shaped transition having a shape and curvature, and connecting a main pole to a yoke region in a magnetic write head, the method comprising:
providing a first photo mask (mask) including a first set of features corresponding to a shaped transition region, wherein the transition connects a main pole region to a yoke region;
providing at least a second mask including a second set of features corresponding to the shaped transition region;
exposing the transition region sequentially through the first mask and the at least second mask, wherein the sequential exposure through the first mask and the second mask utilizes optical proximity effects to minimize distortions of the shaped transition region.
17. The method of claim 16 , further comprising:
exposing the shaped transition region through the first mask using a first set of illumination conditions; and
exposing the shaped transition region through the second mask using a second set of illumination conditions.
18. The method of claim 16 , further comprising:
adjusting an offset between the first mask and the second mask, in order to tune the shape and the curvature of the shaped transition region.
19. The method of claim 18 wherein the first set of illumination conditions are different from the second set of illumination conditions.