MEMS scanning mirror with trenched surface and tapered comb teeth for reducing intertia and deformation

1. A micro-electro-mechanical system (MEMS) mirror device, comprising:

a mirror having a first surface and a second surface, wherein the first surface comprises a plurality of trenches and the second surface comprises a reflective surface;

a beam connected to the mirror;

a plurality of rotational comb teeth connected to the beam;

a first spring connecting the beam to a first bonding pad; and

a second spring connecting the beam to a second bonding pad, wherein the first and the second springs are arranged along a rotational axis of the mirror and the second spring is located between mirror and the first spring.

2. The device of claim 1 , wherein the rotational comb teeth each comprises a tapered shape.

3. The device of claim 1 , further comprising a third spring connecting the beam to the second bonding pad.

4. The device of claim 1 , wherein the second bonding pad is defined within the beam.

5. The device of claim 4 , further comprising a third spring connecting the beam to the second bonding pad.

6. The device of claim 1 , further comprising a first plurality of stationary comb teeth, wherein the first plurality of stationary comb teeth and the plurality of rotational comb teeth are interdigitated in-plane.

7. The device of claim 6 , wherein the plurality of rotational comb teeth is coupled to a first steady or oscillating voltage and the first plurality of stationary comb teeth is coupled to a second steady or oscillating voltage.

8. The device of claim 7 , further comprising a second plurality of stationary comb teeth, wherein the second plurality of stationary comb teeth and the plurality of rotational comb teeth are interdigitated out-of-plane.

9. The device of claim 8 , wherein the second plurality of stationary comb teeth is coupled to a third steady or oscillating voltage.

10. The device of claim 8 , wherein the plurality of rotational comb teeth and the second plurality of stationary rotational comb teeth are coupled to sense a capacitance that indicates a rotational angle of the mirror.

11. The device of claim 1 , wherein the beam further comprises a plurality of holes.

12. The device of claim 1 , further comprising mirror alignment marks for aligning another device to the mirror.

13. The device of claim 1 , wherein a gap surrounding the mirror has a width greater than gaps around other components on the same layer as the mirror.

14. The device of claim 1 , wherein the trenches are located along an outer perimeter of the mirror.

15. A micro-electro-mechanical system (MEMS) mirror device, comprising:

a bottom layer, comprising:

a mirror opening;

a first anchoring pad;

a top layer, comprising:

a mirror located above the mirror opening, the mirror having a top surface comprising a plurality of trenches and a bottom surface comprising a reflective surface;

a beam connected to the mirror;

a first spring connecting the beam to a first bonding pad, the first bonding pad being bonded atop but electrically insulated from the first anchoring pad;

a plurality of rotational comb teeth connected to the beam;

a first plurality of stationary comb teeth connected to a second bonding pad, the second bonding pad being bonded atop but electrically insulated from the first anchoring pad;

wherein the first plurality of stationary comb teeth and the plurality of rotational comb teeth are interdigitated in-plane.

16. The device of claim 15 , wherein:

the bottom layer further comprises a second anchoring pad;

the top layer further comprises a second spring connecting the beam to a third bonding pad, the third bonding pad being bonded atop but electrically insulated from the second anchoring pad, the first and the second springs being arranged along a rotational axis of the mirror, the second spring being located between mirror and the first spring.

17. The device of claim 16 , wherein the mirror has the trenches along an outer perimeter.

18. The device of claim 16 , wherein:

the top layer further comprises a third spring connecting the beam to the third bonding pad.

19. The device of claim 18 , wherein the third bonding pad is located within the beam.

20. The device of claim 16 , wherein the plurality of rotational comb teeth and the first plurality of stationary comb teeth each comprises a tapered shape.

21. The device of claim 16 , wherein the plurality of rotational comb teeth is coupled to a first steady or oscillating voltage and the first plurality of stationary comb teeth is coupled to a second steady or oscillating voltage.

22. The device of claim 16 , wherein the bottom layer further comprises a second plurality of stationary comb teeth, wherein the second plurality of stationary comb teeth and the plurality of rotational comb teeth are interdigitated out-of-plane.

23. The device of claim 22 , wherein the second plurality of stationary comb teeth is coupled to a third steady or oscillating voltage.

24. The device of claim 22 , wherein the plurality of rational comb teeth and the second plurality of rotational comb teeth are coupled to sense a capacitance that indicates a rotational angle of the mirror.

25. The device of claim 22 , wherein a first gap adjacent to the second plurality of stationary comb teeth has greater width and depth than a second gap between adjacent teeth in the second plurality of stationary comb teeth, the first gap accommodating a rotation of the rotational comb teeth.

26. The device of claim 16 , wherein the beam further comprises a plurality of holes.

27. The device of claim 16 , wherein the bottom layer further comprises mirror alignment marks for aligning another device to the mirror.

28. The device of claim 16 , wherein:

the bottom layer further comprises a first separation trench;

the top layer further comprises a second separation trench proximate to the first separation trench, wherein the device is singulated along the first and the second separation trenches.