Compensation of stress effects on pressure sensor components

1. A pressure sensor comprising:

a first component on a first side of a die, the first component having a first characteristic;

a first layer over the first component; and

a first geometry patterned in the first layer,

wherein a first stress is applied to the first component in a first direction, and the first geometry is patterned such that a second stress is applied in a second direction to the first component such that a variation in the first characteristic of the first component due to the first stress is at least reduced by the second stress.

2. The pressure sensor of claim 1 wherein the second stress is determined by the shape of the first geometry in the second direction.

3. The pressure sensor of claim 1 wherein the variation in the first characteristic of the first component due to the first stress is approximately cancelled by the second stress.

4. The pressure sensor of claim 1 wherein the first stress in the first direction is applied to the first component by a first source.

5. The pressure sensor of claim 4 wherein the first source is one of a second geometry in a second layer, a second component, or packaging for the pressure sensor.

6. The pressure sensor of claim 1 wherein the first stress in the first direction is applied to the first component by the first geometry in the first layer.

7. The pressure sensor of claim 1 wherein the first component comprises a diffused resistor.

8. The pressure sensor of claim 1 wherein the first component is a lightly-doped resistor.

9. The pressure sensor of claim 1 wherein the variation in the first characteristic of the first component is a variation in resistance of a resistor.

10. The pressure sensor of claim 1 wherein the first direction and the second direction have an arbitrary angular relationship that is determined to minimize the variation in the first component's first characteristic.

11. The pressure sensor of claim 1 wherein the first component is a MOSFET transistor.

12. The pressure sensor of claim 1 wherein the first component is a MOSFET transistor and the variation in the first characteristic of the first component is a variation in mobility of the MOSFET transistor.

13. The pressure sensor of claim 1 wherein the first layer is a polysilicon layer.

14. The pressure sensor of claim 1 wherein the first layer is a metal layer.

15. The pressure sensor of claim 1 wherein the first layer is an oxide or nitride layer.

16. The pressure sensor of claim 1 wherein the first direction and the second direction are at least approximately orthogonal.

17. The pressure sensor of claim 1 wherein the first geometry comprises an opening.

18. The pressure sensor of claim 1 wherein the first geometry comprises a plurality of openings.

19. A pressure sensor comprising:

a diaphragm surrounded by a frame;

a resistor located on or at least near the diaphragm;

a first layer over the resistor,

a first geometry formed in the first layer,

wherein a first stress is applied to the resistor in a first direction, and the first geometry is formed over the resistor such that the first geometry provides a second stress in a second direction to the resistor, and

wherein the second stress reduces a change in resistance of the resistor caused by the first stress.

20. The pressure sensor of claim 19 wherein the first stress in the first direction is applied to the resistor by a first source.

21. The pressure sensor of claim 20 wherein the first source is one of a second geometry in a second layer, a first component, or packaging for the pressure sensor.

22. The pressure sensor of claim 19 wherein the first stress in the first direction is applied to the resistor by the first geometry in the first layer.

23. The pressure sensor of claim 19 wherein the first geometry is approximately rectangular in shape.

24. The pressure sensor of claim 19 wherein the first geometry includes a plurality of openings.

25. The pressure sensor of claim 19 wherein the resistor is a lightly-doped p-type resistor located in an n-type region.

26. The pressure sensor of claim 25 wherein the first layer is a polysilicon layer.

27. The pressure sensor of claim 26 wherein the resistor is a resistor in a Wheatstone bridge.

28. The pressure sensor of claim 19 wherein the first geometry comprises an opening.

29. A method of manufacturing a pressure sensor, the method comprising:

forming a first resistor on a first side of a wafer, the first resistor having a first resistance;

forming a first layer over the first resistor; and

forming a first geometry in the first layer,

wherein a first stress is applied to the first resistor in a first direction, and the first geometry causes a second stress to be applied in a second direction to the first resistor, such that a variation in the first resistance of the first resistor due to the first stress is at least reduced by the second stress.

30. The method of claim 29 wherein the first stress in the first direction is applied to the first resistor by a first source.

31. The method of claim 30 wherein the first source is one of a second geometry in a second layer, a first component, or packaging for the pressure sensor.

32. The method of claim 29 wherein the first stress in the first direction is applied to the first resistor by the first geometry in the first layer.

33. The method of claim 29 wherein the first resistor is a lightly-doped p-type resistor located in an n-type region.

34. The method of claim 29 wherein the first layer is a polysilicon layer.

35. The method of claim 29 wherein the first geometry includes a plurality of openings.

36. The method of claim 29 wherein the first direction and the second direction are at least approximately orthogonal.

37. The method of claim 29 wherein the first direction and the second direction have an arbitrary angular relationship that is determined to minimize variation in the first resistor's first resistance.

38. The method of claim 29 wherein forming the first geometry comprises forming an opening.