Gridded contacts in semiconductor devices
Mask sets, layout design, and methods for forming contacts in devices are described. In one embodiment, a method of manufacturing a semiconductor device includes a exposing a first photo resist layer using a first light beam thereby forming first features. The first exposure is performed by the first light beam passing through a first dipole illuminator and then a first mask. A dipole axis of the first dipole illuminator is oriented in a first direction. After exposing the first photo resist layer, forming second features using a second exposure with a second light beam. The second exposure is performed by the second light beam passing through a second dipole illuminator and then a second mask. A dipole axis of the second dipole illuminator is oriented in a second direction. The first direction and the second direction are not perpendicular. The first and the second features comprise a pattern for forming contact holes.
1. A method of manufacturing a semiconductor device, the method comprising:
exposing a first photo resist layer using a first light beam thereby forming first features, wherein the first exposure is performed by the first light beam passing through a first dipole illuminator and then a first mask, wherein a dipole axis of the first dipole illuminator is oriented in a first direction; and
after exposing the first photo resist layer, forming second features using a second exposure with a second light beam, wherein the second exposure is performed by the second light beam passing through a second dipole illuminator and then a second mask, wherein a dipole axis of the second dipole illuminator is oriented in a second direction, wherein the first, and the second features comprise a pattern for forming contact holes, and wherein the first direction and the second direction are not perpendicular.
2. The method of claim 1 , wherein the first mask comprises a first plurality of lines oriented in a third direction, wherein the second mask comprises a second plurality of lines oriented in a fourth direction, wherein the third direction is perpendicular to the first direction, and wherein the second direction is perpendicular to the fourth direction.
3. The method of claim 2 , wherein the first plurality of lines comprise first printable features, and first assist features, the first printable features forming the first features.
4. The method of claim 3 , wherein the first assist features comprise sub resolution features.
5. The method of claim 3 , wherein the first assist features comprise printing assist features and are removed using a third mask.
6. The method of claim 3 , wherein the second plurality of lines comprise second printable features, and second assist features, the second printable features forming the second features.
7. The method of claim 6 , wherein the second assist features are not printed and comprise sub resolution features.
8. The method of claim 6 , wherein the second assist features comprise printing assist features and are removed using a third mask.
9. The method of claim 1 , further comprising removing a portion of the first and/or second features using a third mask.
10. The method of claim 1 , wherein the second features are formed in a second photo resist layer.
11. The method of claim 10 , further comprising:
developing and etching the exposed first photo resist layer to form the first features;
freezing the first features;
coating the second photo resist layer after freezing the first features;
developing and etching the exposed second photo resist layer to form the second features; and
freezing the second features.
12. The method of claim 11 , further comprising forming an insulating layer over the substrate, wherein the first photo resist layer is coated over the insulating layer.
13. The method of claim 11 , further comprising etching the insulating layer using the first, the second, and the third features as patterns.
14. The method of claim 10 , wherein the first photo resist and the second photo resist are each a positive tone resist.
15. The method of claim 10 , wherein the first photo resist and the second photo resist are each a negative tone resist.
16. The method of claim 1 , further comprising:
after forming second features, exposing the first and the second features to a third exposure through a third mask, the second features being formed in the first photo resist layer;
removing portions of the first or the second features exposed by the third exposure;
coating a spin on material on the remaining first and second features; and
removing the first and second features to form openings for patterning contact holes.
17. The method of claim 1 , wherein transistors are formed in a substrate under the first photo resist layer before exposing the first photo resist layer.
18. A method of manufacturing a semiconductor device, the method comprising:
forming a first photo resist over a substrate;
passing a first light beam through a first dipole illuminator and then a first mask to form first features on the first photo resist, the first mask comprising a first and a second plurality of lines oriented in a first direction, wherein the first plurality of lines form the first features, and the second plurality of lines comprise assist features, wherein a dipole axis of the first dipole illuminator is oriented in a second direction perpendicular to the first direction;
forming a second photo resist over the first photo resist; and
passing a second light beam through a second dipole illuminator and then a second mask to form second features on the second photo resist, the second mask comprising a third plurality of lines oriented in a third direction, wherein a dipole axis of the second dipole illuminator is oriented in a fourth direction perpendicular to the third direction.
19. The method of claim 18 , wherein the first direction and the third direction are not perpendicular.
20. The method of claim 18 , wherein the first and the second features comprise a pattern for forming contact holes.
21. The method of claim 18 , wherein the first assist features are not printed and comprise sub resolution features.
22. The method of claim 18 , wherein the first assist features comprise printing assist features and are removed using a third mask.
23. The method of claim 18 , wherein the third plurality of lines comprise second printable features, and second assist features, the second printable features forming the second features.
24. The method of claim 23 , wherein the second assist features are not printed and comprise sub resolution features.
25. The method of claim 23 , wherein the second assist features comprise printing assist features and are removed using a third mask.
26. The method of claim 18 , further comprising:
developing and etching the exposed first photo resist layer to form the first features;
freezing the first features;
coating the second photo resist layer after freezing the first features;
developing and etching the exposed second photo resist layer to form the second features; and
freezing the second features.
27. A semiconductor device comprising:
a first plurality of contacts disposed over a first region of a substrate, the first plurality of contacts being disposed as rows and columns on a first grid, wherein the rows and columns of the first grid are not perpendicular to each other; and
a second plurality of contacts disposed over a second region of a substrate, the second plurality of contacts being disposed as rows and columns on a second grid, wherein the rows and columns of the second grid are not perpendicular to each other.
28. The device of claim 27 , wherein the first grid and the second grid are different.
29. The device of claim 27 , wherein each row of the first plurality of contacts is spaced by a first distance, and each column of the first plurality of contacts is spaced by a second distance, and wherein each row of the second plurality of contacts is spaced by a third distance, and each column of the second plurality of contacts is spaced by a fourth distance.