Support structure for MEMS device with particle filter

1. A method for forming a microelectromechanical systems (MEMS) device, the method comprising:

forming a filter stack over a carrier substrate, wherein the filter stack comprises a particle filter layer having a particle filter;

forming a support structure layer over the filter stack;

performing a patterning process on the support structure layer to define a support structure in the support structure layer such that the support structure has one or more segments; and

bonding the support structure to a MEMS structure, wherein the MEMS structure comprises a movable element.

2. The method of claim 1 , wherein the support structure layer is disposed on the filter stack during the patterning process.

3. The method of claim 1 , further comprising:

patterning the carrier substrate to define a carrier substrate opening under the MEMS structure, wherein patterning the carrier substrate occurs after bonding the support structure to the MEMS structure.

4. The method of claim 1 , wherein forming the support structure layer comprises:

performing a thinning process on the support structure layer, wherein a thickness of the support structure layer is less than a thickness of the carrier substrate.

5. The method of claim 1 , wherein forming the support structure layer comprises:

depositing the support structure layer on an upper surface of the filter stack by a chemical vapor deposition (CVD) process, wherein the support structure layer and the particle filter respectively comprise polysilicon.

6. The method of claim 1 , wherein forming the filter stack comprises:

forming a first dielectric layer over the carrier substrate;

forming the particle filter layer over the first dielectric layer; and

patterning the particle filter layer to define the particle filter while the particle filter layer is disposed on the carrier substrate.

7. The method of claim 6 , wherein forming the filter stack further comprises:

forming a second dielectric layer over the particle filter layer; and

forming a third dielectric layer over the second dielectric layer;

wherein the support structure layer is formed along an upper surface of the third dielectric layer.

8. The method of claim 7 , wherein an annealing process is performed after forming the particle filter layer and before patterning the particle filter layer to define the particle filter.

9. A method for forming a semiconductor structure, the method comprising:

depositing a particle filter layer over a carrier substrate;

patterning the particle filter layer while the particle filter layer is disposed on the carrier substrate to define a particle filter in the particle filter layer;

forming a support structure layer over the particle filter layer such that the support structure layer comprises a support structure, wherein the support structure comprises a plurality of support structure openings that extend through the support structure layer; and

bonding a microelectromechanical systems (MEMS) structure to the support structure, wherein the MEMS structure comprises a moveable element.

10. The method of claim 9 , wherein the MEMS structure is formed over a sacrificial substrate before bonding the MEMS structure to the support structure, the method further comprising:

performing a thinning process on the carrier substrate; and

removing the sacrificial substrate from along the MEMS structure after bonding the MEMS structure to the support structure.

11. The method of claim 9 , wherein forming the support structure comprises:

patterning the support structure layer while the support structure layer is disposed on the particle filter layer.

12. The method of claim 9 , wherein after patterning the particle filter layer the particle filter comprises a plurality of filter openings that extends through the particle filter layer, wherein when viewed from above the support structure openings respectively have a different shape than the filter openings.

13. The method of claim 9 , wherein the particle filter comprises polysilicon and the support structure comprises silicon.

14. A microelectromechanical systems (MEMS) device comprising:

a MEMS structure overlying a carrier substrate, wherein the MEMS structure comprises a moveable element;

a filter stack disposed between the carrier substrate and the MEMS structure, wherein the filter stack includes a particle filter layer having a particle filter, wherein a plurality of filter openings extends through the particle filter; and

a support structure layer disposed between the particle filter and the MEMS structure, wherein a plurality of support structure openings extends through the support structure layer, wherein when viewed from above the support structure openings respectively have a different shape than the filter openings.

15. The MEMS device of claim 14 , wherein the particle filter layer comprises an upper particle filter layer, a lower particle filter layer, and a middle particle filter layer disposed between the upper and lower particle filter layers, wherein the upper and lower particle filter layers comprise a first material, and wherein the middle particle filter layer comprises a second material different from the first material.

16. The MEMS device of claim 15 , wherein the first material is silicon nitride and the second material is polysilicon.

17. The MEMS device of claim 14 , wherein the support structure layer comprises first elongated support segments extending between a first pair of opposing inner sidewalls of the support structure layer, wherein a width of each first elongated support segment is less than a diameter of each filter opening.

18. The MEMS device of claim 17 , wherein the first elongated support segments extend continuously in a first direction, wherein the support structure layer further comprises second elongated support segments extending continuously in a second direction orthogonal to the first direction, wherein the first and second elongated support segments respectively have straight opposing sidewalls.

19. The MEMS device of claim 14 , wherein the support structure openings have a polygon shape and the filter openings have a circular shape.

20. The method of claim 1 , wherein the carrier substrate comprises opposing sidewalls defining an opening.