Microelectromechanical structure and a method for making the same

1. An etching method comprising:

loading a workpiece into an etching chamber, the workpiece comprising a first area to be removed by a spontaneous vapor phase chemical etchant and a second area to remain after the first area being removed, wherein the second area comprises an intermetallic compound;

providing the spontaneous vapor phase etchant to the etching chamber;

removing the first area while leaving behind the second area; and

wherein the chemical etchant comprises a chemical species that is selected from the group consisting of: interhalogens and noble gas halides.

2. The method of claim 1 , wherein the intermetallic compound comprises an early transition metal selected from column 4 in the periodic table.

3. The method of claim 1 , wherein the intermetallic compound comprises an element that is Tc or Re.

4. The method of claim 1 , wherein the intermetallic material is selected from the group consisting of NiAl x , and TiNi x .

5. The method of claim 1 , wherein the intermetallic material is VAl x , WTe x , TiFe x , TiPd x , AlPd x , MoPd x , MoNi x , MoFe x , CoCr x , CoMn x , NiW x , NiV x , NiTi x Al y , NbAl x , MoPd x , AICu x , CuZn x , or TaAl x .

6. The method of claim 1 , wherein the first area comprises a material that is elemental metal, metalloid, metal alloy, metal silicide, W x N or TaN x .

7. The method of claim 1 , wherein the workpiece is a micromirror array.

8. The method of claim 1 , wherein the workpiece is a microelectromechanical device.

9. The method of claim 1 , wherein the interhalogen comprises bromine trifluoride.

10. The method of claim 1 , wherein the noble gas halide comprises xenon difluoride.

11. The method of claim 1 , wherein vapor phase etchant further comprises a diluent gas that is a noble gas.

12. The method of claim 1 , wherein the intermetallic compound comprises an early transition metal selected from column 5 in the periodic table.

13. The method of claim 1 , wherein the intermetallic compound comprises an early transition metal selected from column 6 in the periodic table.

14. The method of claim 1 , wherein the intermetallic compound comprises an element that is a late transition metal.

15. The method of claim 14 , wherein the intermetallic compound comprises an element that is Ru, Rh, Os, Ir, or Pt.

16. The method of claim 1 , wherein the intermetallic compound is AlTi x .

17. The method of claim 16 , wherein the workpiece further comprises a barrier layer that remains after removal of the first area.

18. The method of claim 1 , wherein the workpiece is a microstructure comprising a silicon substrate.

19. The method of claim 18 , wherein the first area comprises amorphous silicon; and wherein the microstructure further comprises a structural layer and a barrier layer disposed between the structural layer and the first area.

20. The method of claim 18 , further comprising: removing the barrier layer disposed between the structural layer and the first area.

21. The method of claim 1 , wherein the second area further comprises O or N.

22. The method of claim 21 , wherein the O or N in the second area is 15 atomic % or less in weight.

23. The method of claim 21 , wherein the O or N in the second area is 5% atomic or less in weight.

24. The method of claim 21 , wherein O or N in the second area is in a form of TiO x , TiN x , AlO x or AlN x .

25. A method comprising:

forming a workpiece, comprising:

providing a substrate;

depositing a first and second sacrificial layer on the substrate; and

forming a first and second structural layers on the sacrificial layers, wherein the first and second structural layers comprises an intermetallic compound;

loading the workpiece to an etching chamber; and

removing at least a portion of the first and second sacrificial layers using a spontaneous vapor phase chemical etchant, wherein the chemical etchant comprises a chemical species that is selected from the group consisting of: interhalogens and noble gas halides.

26. The method of claim 25 , wherein the intermetallic compound comprises an early transition metal selected from column 4 in the periodic table.

27. The method of claim 25 , wherein the intermetallic compound comprises an element that is Tc or Re.

28. The method of claim 25 , wherein the intermetallic material is selected from the group consisting of Ni x Al y and TiNi.

29. The method of claim 25 , wherein the intermetallic material is VAl x , WTe x , TiFe x , TiPd x , AlPd x , MoPd x , MoNi x , MoFe x , CoCr x , CoMn x , NiW x , NiV x , NiTi x Al y , NbAl x , MoPd x , AlCu x , CuZn x , or TaAl x .

30. The method of claim 25 , wherein the first or the second sacrificial layer comprises a material that is elemental metal, metalloid, metal alloy, metal silicide, W x N or TaN x .

31. The method of claim 25 , wherein the workpiece is a micromirror array.

32. The method of claim 25 , wherein the workpiece is a microelectromechanical device.

33. The method of claim 25 , wherein the interhalogen comprises bromine trifluoride.

34. The method of claim 25 , wherein the noble gas halide comprises xenon difluoride.

35. The method of claim 25 , wherein vapor phase etchant further comprises a diluent gas that is a noble gas.

36. The method of claim 25 , wherein the intermetallic compound comprises an early transition metal selected from column 5 in the periodic table.

37. The method of claim 25 , wherein the intermetallic compound comprises an early transition metal selected from column 6 in the periodic table.

38. The method of claim 25 , wherein the intermetallic compound comprises an element that is a late transition metal.

39. The method of claim 38 , wherein the intermetallic compound comprises an element that is Ru, Rh, Os, Ir, or Pt.

40. The method of claim 25 , wherein the intermetallic compound is AITi x .

41. The method of claim 40 , wherein the workpiece further comprises a barrier layer that remains after removal of the first and second sacrificial layers.

42. The method of claim 25 , wherein the workpiece is a microstructure comprising a silicon substrate.

43. The method of claim 42 , wherein the first or the second sacrificial layer comprises amorphous silicon; and wherein the microstructure further comprises a barrier layer disposed between one of the first and second structural layers and one of the first and second sacrificial layers.

44. The method of claim 43 , further comprising: removing the barrier layer.

45. The method of claim 25 , wherein the first or the second structural layer further comprises O or N.

46. The method of claim 45 , wherein the O or N in the second area is 15 atomic % or less in weight.

47. The method of claim 45 , wherein the O or N in the second area is 5 atomic % or less in weight.

48. The method of claim 45 , wherein O or N in the second area is in a form of TiO x , TiN x , AlO x or AlN x .

49. A method for making a microstructure, the method comprising;

depositing a sacrificial material on a substrate, the sacrificial material comprising a metal;

depositing a structural layer after depositing the sacrificial material, wherein the structural layer comprises a material other than the sacrificial material, and wherein the material of the structural layer comprises an intermetallic compound; and

removing the sacrificial material with a spontaneous vapor phase chemical etchant, wherein the chemical etchant comprises a chemical species that is selected from the group consisting of: interhalogens and noble gas halides.

50. The method of claim 49 , wherein the sacrificial material comprises at least 25 percent in weight of said metal.

51. The method of claim 49 , wherein the sacrificial material comprises at least 50 percent in weight of said metal.

52. The method of claim 49 , wherein the sacrificial material comprises at least 90 percent in weight of said metal.

53. The method of claim 49 , wherein the interhalogen comprises bromine trifluoride.

54. The method of claim 49 , wherein the etchant is mixed with a diluent gas that is He, N 2 , Ne, Ar, Ke, or Xe.

55. The method of claim 49 , wherein the noble gas halide comprises xenon difluoride.

56. The method of claim 55 , wherein the metal of the sacrificial material is a transition metal that is an early transition metal.

57. The method of claim 56 , wherein the metal is a sputtered elemental metal material.