Constraint for a sensor assembly

1. A constraint for a sensor assembly, comprising:

a silicon wafer having a first side, a second side opposite to the first side, and a passageway extending through the silicon wafer from the first side to the second side, the first side is a continuous planar surface except for the passageway; and

a flexible structure extending from the second side and aligned with an outermost lateral surface of the silicon wafer in a height direction extending between the first side and the second side of the silicon wafer, the flexible structure includes a plurality of beams and at least one trench disposed between the plurality of beams, a total width of the silicon wafer outside of the passageway in a width direction perpendicular to the height direction is greater than a total width of the beams in the width direction.

2. The constraint of claim 1 , wherein the silicon wafer has a thickness in the height direction, the flexible structure has a depth in the height direction, the depth is equal to the thickness.

3. The constraint of claim 1 , wherein each of the plurality of beams has a cross-sectional shape, the cross-sectional shape is a square, a rectangular, a circular, or a hexagonal shape.

4. The constraint of claim 1 , wherein each of the beams extends parallel to the height direction.

5. The constraint of claim 4 , wherein one of the beams is flush with the outermost lateral surface of the silicon wafer.

6. The constraint of claim 1 , wherein the beams each have a beam width in the width direction and the trenches each have a spacing between the beams in the width direction, the beam width is equal to the spacing.

7. The constraint of claim 6 , wherein each of the beams is spaced apart from the passageway by at least the spacing in the width direction.

8. The constraint of claim 1 , wherein the plurality of beams are concentric to one another about the passageway.

9. The constraint of claim 1 , wherein the plurality of beams are monolithically formed in a single piece with the silicon wafer.

10. The constraint of claim 9 , wherein the plurality of beams are etched into the silicon wafer.

11. The constraint of claim 10 , wherein the silicon wafer has a (100) plane orientation and the plurality of beams are etched by deep reactive-ion etching.

12. The constraint of claim 10 , wherein the silicon wafer has a (110) plane orientation and the plurality of beams are etched by wet etching.

13. The constraint of claim 1 , wherein the flexible structure is formed of a same material as the silicon wafer.

14. The constraint of claim 1 , wherein the passageway of the silicon wafer is the only passageway extending through the silicon wafer from the first side to the second side.