Apparatus and method for controlling wafer strain compensation along the X / Y direction

Abstract

Methods, apparatus, and structures for mitigating wafer warping of semiconductor wafers are provided. The deposition of a back layer stack can mitigate wafer warping that varies in the orthogonal direction. Each back layer may be deposited by a back layer deposition apparatus.

Claims

1. A method for reducing the warping of a substrate, wherein the method is A step of receiving a substrate having a front and a back surface, wherein the substrate has a first curvature in the x-direction and a second curvature in the y-direction; (a) A step of forming a first back layer on the back surface of the substrate, wherein the first back layer compensates for the first warp more than it compensates for the second warp, or compensates for the second warp more than it compensates for the first warp, and the first back layer has a first type of internal stress and a first non-uniform thickness profile, (b) A step of forming a second back layer on the back surface of the substrate, wherein the second back layer compensates for either the first or second warpage which is less compensated by the first back layer, and the second back layer has a second type of internal stress opposite to the first type of internal stress, and a second non-uniform thickness profile, The steps include performing one or more cycles of the following: Includes, When the first back layer and the second back layer are formed, the first non-uniform thickness profile and the second non-uniform thickness profile complement each other so as to provide a complementary film stack having substantially flat surfaces on the back surface of the substrate. method.

2. The method according to claim 1, wherein the substrate is a semiconductor wafer having an integrated circuit partially manufactured on the front surface.

3. The method according to claim 1, wherein the substrate has a saddle-shaped curvature.

4. The method according to claim 1, further comprising the step of determining that the magnitude of the first curvature is greater than the magnitude of the second curvature before forming the first back surface layer.

5. The method according to claim 4, further comprising the step of rotating the substrate based on the determination that the magnitude of the first warp is greater than the magnitude of the second warp, before forming the first back surface layer.

6. The method according to claim 1, wherein the first non-uniform thickness profile is a curved bar that is thicker towards the center of the substrate than at the edges of the substrate.

7. The method according to claim 6, wherein the curved bar has a longitudinal axis substantially parallel to the y-direction.

8. The method according to claim 6, wherein the curved bar has a substantially parabolic shape, perpendicular to the x and y directions, and moving away from the back surface of the substrate as a function of the x direction, with a thickness that changes in the z direction.

9. The method according to claim 1, wherein the second non-uniform thickness profile is a curved channel that is thicker towards the edge of the substrate than towards the center of the substrate.

10. The method according to claim 9, wherein the curved channel has a parabolic shape with a thickness that changes in the z direction, and moves away from the back surface of the substrate as a function of the x direction.

11. The method according to claim 1, wherein the first type of internal stress is a tensile stress.

12. The method according to claim 1, wherein the first type of internal stress is compressive stress.

13. The method according to claim 1, further comprising the step of forming a third back layer on the back surface of the substrate, wherein the third back layer has a uniform shape and either the first type or the second type of internal stress.

14. The method according to claim 13, wherein the type and magnitude of the internal stress of the third back layer are based on the warping of the substrate after the first back layer and the second back layer are formed.

15. The method according to claim 1, further comprising the step of identifying the first curvature value and the second curvature value, wherein the step of forming the first back layer and the step of forming the second back layer are based on the first curvature value and the second curvature value.

16. The method according to claim 1, further comprising the step of identifying the first warp value and the second warp value, wherein the magnitude of the internal stress in the first back layer and the magnitude of the internal stress in the second back layer are based on the first warp value and the second warp value.

17. The method according to claim 1, wherein the one or more cycles are two or more cycles.

18. The method according to claim 1, wherein the total thickness of the layers deposited during one or more cycles is at least about 2 μm.

19. The method according to claim 1, wherein the first back layer and the second back layer have a first thickness in total, and each cycle of (a) and (b) deposits complementary profile layers having the first thickness.

20. The method according to claim 19, wherein the first thickness is less than approximately 1 μm.

21. The method according to claim 1, wherein the first back layer and the second back layer exhibit a change in wafer warpage compensation of less than about 20% after annealing.

22. The method according to claim 1, further comprising the step of forming a third back layer on the back surface of the substrate after performing one or more of the cycles, wherein the third back layer increases the flatness of the back surface of the substrate.

23. The method according to claim 1, further comprising the steps of performing a plasma treatment after forming the first back surface layer, performing a plasma treatment after forming the second back surface layer, or both, wherein the plasma treatment improves the adhesion of the back surface layers.

24. It is a substrate, One or more front layers on the front surface of the substrate, wherein the substrate has a first curvature in the x-direction and a second curvature in the y-direction, A first back layer on the back surface of the substrate, wherein the first back layer compensates for the first warp more than it compensates for the second warp, or compensates for the second warp more than it compensates for the first warp, and the first back layer has a first type of internal stress and a first non-uniform thickness profile, A second back layer on the back surface of the substrate, wherein the second back layer compensates for either the first or second warpage which is less compensated by the first back layer, and the second back layer has a second type of internal stress opposite to the first type of internal stress, and a second non-uniform thickness profile. Includes, When the first back layer and the second back layer are formed, the first non-uniform thickness profile and the second non-uniform thickness profile complement each other so as to provide a complementary film stack having substantially flat surfaces on the back surface of the substrate. substrate.

25. The substrate according to claim 24, wherein if the one or more front layers are not compensated by the first back layer, the substrate has a first or second warp of about 300 μm or more.

26. The substrate according to claim 24, wherein the first non-uniform thickness profile is a curved bar that is thicker toward the center of the substrate than toward the edges of the substrate.

27. The substrate according to claim 26, wherein the curved bar has a longitudinal axis substantially parallel to the y-direction.

28. The substrate according to claim 26, wherein the curved bar has a substantially parabolic shape, perpendicular to the x and y directions, and moving away from the back surface of the substrate as a function of the x direction, with a thickness that changes in the z direction.

29. The substrate according to claim 24, wherein the second non-uniform thickness profile is a curved channel that is thicker toward the edge of the substrate than toward the center of the substrate.

30. The substrate according to claim 29, wherein the curved channel has a parabolic shape with a thickness that changes in the z direction, and moves away from the back surface of the substrate as a function of the x direction.

31. The substrate according to claim 24, wherein the internal stress of the first type is tensile stress.

32. The substrate according to claim 24, wherein the internal stress of the first type is compressive stress.

33. The substrate according to claim 24, further comprising a third back surface layer on the back surface of the substrate, wherein the third back surface layer has a uniform shape and either the first or second type of internal stress.

34. The substrate according to claim 33, wherein the type and magnitude of the internal stress of the third back layer are based on the warping of the substrate after the first back layer and the second back layer are formed.

35. The substrate according to claim 24, further comprising an additional complementary film stack.

36. The substrate according to claim 35, wherein both the complementary film stack and the additional complementary film stack alternate between the first back layer and the second back layer.

37. The substrate according to claim 35, wherein the total thickness of all complementary film stacks is at least about 2 μm.

38. The substrate according to claim 35, wherein the thickness of each complementary film stack is less than approximately 1 μm.

39. The substrate according to claim 35, wherein the change in the total wafer warpage compensation of all the complementary film stacks after annealing is less than about 20%.

40. The substrate according to claim 35, further comprising a third back layer on the back surface of the substrate deposited after all of the complementary film stacks, wherein the third back layer increases the flatness of the back surface of the substrate.

41. An apparatus for semiconductor processing, wherein the apparatus is process chamber and A controller comprising memory and a processor, A step of receiving a substrate having a front and a back surface, wherein the substrate has a first curvature in the x-direction and a second curvature in the y-direction; (a) A step of forming a first back layer on the back surface of the substrate, wherein the first back layer compensates for the first warp more than it compensates for the second warp, or compensates for the second warp more than it compensates for the first warp, and the first back layer has a first type of internal stress and a first non-uniform thickness profile, (b) A step of forming a second back layer on the back surface of the substrate, wherein the second back layer compensates for either the first or second warpage which is less compensated by the first back layer, and the second back layer has a second type of internal stress opposite to the first type of internal stress, and a second non-uniform thickness profile, The steps include performing one or more cycles of the following: A controller and Equipped with, When the first back layer and the second back layer are formed, the first non-uniform thickness profile and the second non-uniform thickness profile complement each other so as to provide a complementary film stack having substantially flat surfaces on the back surface of the substrate. Device.

Images