Semiconductor wafers with reduced roll-off and bonded and unbonded SOI structures produced from same
View Patent ↗The disclosure relates to preparation of silicon on insulator structures with reduced unbonded regions and to methods for producing such wafers by minimizing the roll-off amount (ROA) of the handle and donor wafers. Methods for polishing wafers are also provided.
1. A bonded silicon on insulator structure, the bonded structure comprising a handle wafer, a donor wafer, a dielectric layer between the handle wafer and the donor wafer, the dielectric layer being partially bonded to the handle wafer, the bonded silicon on insulator structure having a central axis, a circumferential edge and a radius extending from the central axis to the circumferential edge, wherein the bonding between the dielectric layer and the handle wafer extends from the central axis of the bonded silicon on insulator structure to a point at least about 99.4% of the radius of the bonded silicon on insulator structure.
2. The bonded silicon on insulator structure as set forth in claim 1 wherein at least one of donor wafer and the handle wafer has a thickness ROA of less than about −700 nm.
3. The bonded silicon on insulator structure as set forth in claim 1 wherein at least one of donor wafer and the handle wafer has a thickness ROA of less than about −400 nm.
4. The bonded silicon on insulator structure as set forth in claim 1 wherein at least one of the donor wafer and the handle wafer has a front surface zdd of less than about −1100 nm/mm 2 .
5. The bonded silicon on insulator structure as set forth in claim 1 wherein the dielectric layer and the handle wafer form an interface, the handle wafer having about 3 or less brightfield defects of a size greater than about 6 nm at the interface.
6. The bonded silicon on insulator structure as set forth in claim 1 wherein the dielectric layer and the handle wafer form an interface, the handle wafer having less than about 6 brightfield defects of a size greater than about 4.8 nm at the interface.
7. The bonded silicon on insulator structure as set forth in claim 1 wherein the dielectric layer and the donor wafer form an interface, the donor wafer having 3 or less brightfield defects of a size greater than about 6 nm at the interface.
8. The bonded silicon on insulator structure as set forth in claim 1 wherein the dielectric layer and the donor wafer form an interface, the donor wafer having less than about 6 brightfield defects of a size greater than about 4.8 nm at the interface.
9. A bonded silicon on insulator structure, the bonded structure comprising a handle wafer, a donor wafer, a dielectric layer between the handle wafer and the donor wafer, the dielectric layer being partially bonded to the donor wafer, the bonded silicon on insulator structure having a central axis, a circumferential edge and a radius extending from the central axis to the circumferential edge, wherein the bonding between the dielectric layer and the donor wafer extends from the central axis of the bonded silicon on insulator structure to a point at least about 99.4% to about 99.9% of the radius of the bonded silicon on insulator structure.
10. The bonded silicon on insulator structure as set forth in claim 9 wherein at least one of the donor wafer and the handle wafer has a thickness ROA of less than about −700 nm.
11. The bonded silicon on insulator structure as set forth in claim 9 wherein at least one of the donor wafer and the handle wafer has a thickness ROA of less than about −400 nm.
12. The bonded silicon on insulator structure as set forth in claim 9 wherein at least one of the donor wafer and the handle wafer has a front surface zdd of less than about −1100 nm/mm 2 .
13. The bonded silicon on insulator structure as set forth in claim 9 wherein the dielectric layer and the handle wafer form an interface, the handle wafer having about 3 or less brightfield defects of a size greater than about 6 nm at the interface.
14. The bonded silicon on insulator structure as set forth in claim 9 wherein the dielectric layer and the handle wafer form an interface, the handle wafer having less than about 6 brightfield defects of a size greater than about 4.8 nm at the interface.
15. The bonded silicon on insulator structure as set forth in claim 9 wherein the dielectric layer and the donor wafer form an interface, the donor wafer having 3 or less brightfield defects of a size greater than about 6 nm at the interface.
16. The bonded silicon on insulator structure as set forth in claim 9 wherein the dielectric layer and the donor wafer form an interface, the donor wafer having less than about 6 brightfield defects of a size greater than about 4.8 nm at the interface.
17. A silicon on insulator structure, the structure comprising a handle wafer, a silicon layer, a dielectric layer between the handle wafer and the silicon layer, and an interface between the dielectric layer and the handle wafer, the handle wafer having a central axis, a circumferential edge and a radius extending from the central axis to the circumferential edge, wherein the silicon layer extends from the central axis of the handle wafer to a point at least about 98.9% of the radius of the handle wafer, the handle wafer having about 3 or less brightfield defects of a size greater than about 6 nm at the interface.
18. The silicon on insulator structure as set forth in claim 17 wherein the silicon layer extends from the central axis of the handle wafer to a point at least about 99.4% of the radius of the handle wafer.
19. The silicon on insulator structure as set forth in claim 17 wherein the dielectric layer extends from the central axis of the handle wafer to a point at least about 98.9% of the radius of the handle wafer.
20. The silicon on insulator structure as set forth in claim 17 wherein the dielectric layer extends from the central axis of the handle wafer to a point at least about 99.4% of the radius of the handle wafer.
21. The silicon on insulator structure as set forth in claim 17 wherein the handle wafer is free of brightfield defects of a size greater than 6 nm at the interface.
22. The silicon on insulator structure as set forth in claim 17 wherein the handle wafer has less than about 6 brightfield defects of a size greater than about 4.8 nm at the interface.
23. The silicon on insulator structure as set forth in claim 17 wherein the dielectric layer and the silicon layer form an interface, the silicon layer having about 3 or less brightfield defects of a size greater than about 6 nm at the interface.
24. The silicon on insulator structure as set forth in claim 17 wherein the dielectric layer and the silicon layer form an interface, the silicon layer having less than about 6 brightfield defects of a size greater than about 4.8 nm at the interface.
25. The silicon on insulator structure as set forth in claim 17 wherein the handle wafer has a thickness ROA of less than about −700 nm or less.
26. The silicon on insulator structure as set forth in claim 17 wherein the handle wafer has a front surface zdd of less than about −1100 nm/mm 2 .
27. A semiconductor wafer having a central axis, a front surface and a back surface that are generally perpendicular to the central axis, a circumferential edge joining the front and back surfaces and a radius extending from the central axis to the circumferential edge, the wafer having a thickness roll-off amount (ROA) of less than about −700 nm, the wafer having about 3 or less brightfield defects of a size greater than about 6 nm at the front surface of the wafer.
28. The semiconductor wafer as set forth in claim 27 wherein the wafer is free of brightfield defects of a size greater than 6 nm at the front surface of the wafer.
29. The semiconductor wafer as set forth in claim 27 wherein the wafer has less than about 6 brightfield defects of a size greater than about 4.8 nm.
30. The semiconductor wafer as set forth in claim 27 wherein the wafer is free of brightfield defects of a size greater than about 4.8 nm.
31. The semiconductor wafer as set forth in claim 27 wherein the wafer has a thickness ROA of less than about −400 nm.
32. The semiconductor wafer as set forth in claim 27 wherein the wafer has an annular edge portion between the circumferential edge of the wafer and 98% of the radius and wherein the thickness ROA is the distance between a reference line and a third discreet point in an edge portion of the wafer thickness profile, the reference line extending from a first discreet point and a second discreet point on the thickness profile.
33. The semiconductor wafer as set forth in claim 32 wherein:
the distance between the first discreet point and the central axis of the structure is about 82.7% of the radius of the structure;
the distance between the second discreet point and the central axis of the structure is about 93.3% of the radius of the structure; and
the distance between the third discreet point and the central axis of the structure is about 99.3% of the radius of the structure.
34. The semiconductor wafer as set forth in claim 32 wherein the reference line is fitted as a first order linear line.
35. The semiconductor wafer as set forth in claim 32 wherein the reference line is fitted as a third order polynomial.
36. The semiconductor wafer as set forth in claim 27 wherein the thickness ROA is an average thickness ROA.
37. The semiconductor wafer as set forth in claim 36 wherein the average thickness ROA is an average of eight thickness ROA measurements taken at eight wafer radii.
38. The semiconductor wafer as set forth in claim 27 wherein the wafer has a front surface zdd of less than about −1100 nm/mm 2 .
39. The semiconductor wafer as set forth in claim 27 wherein the wafer is a handle wafer.
40. The semiconductor wafer as set forth in claim 27 wherein the wafer is a donor wafer.
41. The semiconductor wafer as set forth in claim 27 wherein the semiconductor wafer is composed of single crystal silicon.
42. The semiconductor wafer as set forth in claim 27 wherein the semiconductor wafer is one wafer of a population of 25 wafers, wherein each wafer has a central axis, a front surface and a back surface that are generally perpendicular to the central axis, a circumferential edge joining the front and back surfaces and a radius extending from the central axis to the circumferential edge, each wafer having a thickness roll-off amount (ROA) of less than about −700 nm, the wafer having about 3 or less brightfield defects of a size greater than about 6 nm at the front surface of the wafer.
43. The semiconductor wafer as set forth in claim 42 wherein each wafer is free of brightfield defects of a size greater than 6 nm at the front surface of the wafer.
44. The semiconductor wafer as set forth in claim 42 wherein each wafer has less than about 6 brightfield defects of a size greater than about 4.8 nm.
45. The semiconductor wafer as set forth in claim 42 wherein each wafer is free of brightfield defects of a size greater than about 4.8 nm.
46. The semiconductor wafer as set forth in claim 42 wherein each wafer has a thickness ROA of less than about −400 nm.