Sensor isolation system

• US 20030038415A1
• Filed: 05/09/2002
• Published: 02/27/2003
• Est. Priority Date: 08/21/2001
• Status: Active Grant

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Anderson, Richard S., Marinis, Thomas F., Hanson, David S., Soucy, Joseph W., Kasparian, Frederick J.
• Granted Patent: US 6,937,479 B2
• Time in Patent Office: Days
• US Class Current: 267/160
• CPC Class Codes: B81B 7/0048 between the MEMS die and the substrate
• CPC Class Codes: F16F 1/18 Leaf springs planar springs in general F16F1/027; "Belleville"-type springs with generally radial arms F16F1/324
• CPC Class Codes: F16F 15/073 using only leaf springs
• CPC Class Codes: G01D 11/30 Supports specially adapted for an instrument; Supports specially adapted for a set of instruments

Abstract

A sensor isolation system including a sensor, a package for the sensor, and a compliant interposer disposed between the sensor and the package and interconnecting the sensor to the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

Claims

1. A sensor isolation system comprising:

a sensor;

a package for the sensor; and

a compliant interposer disposed between the sensor and the package and interconnecting the sensor to the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

2. The system of claim 1 in which the sensor is a micromachined die.

3. The system of claim 2 in which the die is configured as an accelerometer.

4. The system of claim 2 in which the die is configured as a gyroscope.

5. The system of claim 2 in which the die is configured as a MEMs sensor.

6. The system of claim 1 in which the package is a chip carrier.

7. The system of claim 6 in which the chip carrier includes a floor and walls upstanding from the floor.

8. The system of claim 7 in which the interposer interconnects the sensor with the walls of the chip carrier cradling the sensor above the floor of the chip carrier.

9. The system of claim 7 in which the interposer is disposed on the floor of the chip carrier and supports the sensor above the floor of the chip carrier.

10. The system of claim 9 in which the interposer includes a peripheral base portion with inwardly directed spring elements, the sensor disposed on the inwardly direct spring elements, the peripheral base portion attached to the floor of the chip carrier.

11. The system of claim 9 in which the interposer includes a central base portion with outwardly extending spring elements, the sensor disposed on the central base portion, the outwardly extending spring elements attached to the floor of the chip carrier.

12. The system of claim 1 in which the package includes a substrate and the compliant interposer is disposed between the sensor and the substrate.

13. The system of claim 12 in which the interposer includes a peripheral base portion with inwardly directed spring elements, the peripheral base portion attached to the substrate, the inwardly directed spring elements supporting the sensor above the substrate.

14. The system of claim 12 in which the interposer includes a central base portion with outwardly extending spring elements, the sensor disposed on the central base portion, the outwardly extending spring elements attached to the substrate.

15. The system of claim 1 in which the compliant interposer includes a plurality of spring members interconnecting and supporting the sensor with respect to the package.

16. The system of claim 15 in which the package includes a floor and walls upstanding from the floor, each spring member extending between a wall and the sensor.

17. The system of claim 16 in which the walls of the package include a shelf, the sensor is a die, and each spring member includes a seat for the die and an arm extending from the seat terminating in a tab residing on the shelf.

18. The system of claim 1 in which the compliant interposer includes a continuous member interconnecting and supporting the sensor with respect to the package.

19. The system of claim 18 in which the package includes a floor and walls upstanding from the floor, the continuous member disposed adjacent selected walls.

20. The system of claim 19 in which the walls of the package include a shelf, the sensor is a die, and the continuous member includes spaced seats for supporting the die above the floor and tabs residing on the shelf.

21. The system of claim 20 in which the seats are oriented parallel to the tabs.

22. The system of claim 21 in which the seats are angled.

23. The system of claim 20 in which the continuous member is U-shaped having a base portion and two spaced legs extending from the base portion, the base portion including at least one seat and one tab, each spaced leg also including at least one seat and one tab.

24. The system of claim 23 in which the seats are offset from the tabs.

25. The system of claim 24 in which the seats on the legs are diametrically opposed and the tabs on the legs are diametrically opposed.

26. The system of claim 1 in which the compliant interposer is integral with a portion of the package.

27. The system of claim 1 in which the compliant interposer includes a peripheral base portion and inwardly directed spring elements, the sensor disposed on the inwardly directed spring elements, the peripheral base portion attached to the package.

28. The system of claim 27 in which the inwardly directed spring elements are integral with the peripheral base portion.

29. The system of claim 27 in which the peripheral base portion is a component of the package.

30. The system of claim 27 in which each inwardly directed spring element extends first along a first axis and then turns to extend along a second axis.

31. The system of claim 30 in which the first and second axis are orthogonal.

32. The system of claim 27 in which the inwardly directed spring elements lie the same plane as the peripheral base portion.

33. The system of claim 1 in which the compliant interposer includes a central base portion with outwardly extending spring elements, the sensor disposed on the central base portion, the outwardly extending spring elements attached to the package.

34. The system of claim 33 in which the outwardly extending spring elements are integral with the central base portion.

35. The system of claim 33 in which the outwardly extending spring elements lie in the same plane as the central base portion.

36. The system of claim 33 in which the outwardly extending spring elements are a component of the package.

37. The system of claim 33 in which each outwardly extending spring element includes a tab portion connected to the central base portion and a pair of arms extending from the tab.

38. The system of claim 37 of which the arms extend transversely from the tab portion in opposite directions.

39. The system of claim 38 in which the arms extend along the periphery of the central base portion.

40. The system of claim 37 further including a channel through the arms and the tab portion.

41. The system of claim 40 in which the channel is continuous.

42. The system of claim 1 in which the compliant interposer is configured to position the sensor flat with respect to the package.

43. The system of claim 1 in which the compliant interposer is configured to position the sensor at an angle with respect to the package.

44. The system of claim 1 in which the compliant interposer includes vibration damping structure.

45. The system of claim 44 in which the vibration damping structure is a coating on the compliant interposer.

46. The system of claim 1 in which the interposer includes a heater.

47. The system of claim 46 in which the heater is a resistance heater.

48. The system of claim 46 in which the interposer includes a planar base portion and spring elements extending therefrom, the heater disposed on the planar base portion.

49. The system of claim 48 in which the heater is a pattern of conductive lands disposed on the planar base portion.

50. The system of claim 48 in which the spring elements extend inwardly from the planar base portion.

51. The system of claim 48 in which the spring elements extend outwardly from the planar based portion.

52. The system of claim 1 in which the interposer includes a measurement subsystem.

53. The system of claim 52 in which the measurement subsystem is a temperature sensor.

54. The system of claim 53 in which the temperature sensor includes a pattern of conductive lands disposed on the interposer, the conductive lands made of a material which changes in resistance as a known function of temperature.

55. The system of claim 52 in which the interposer includes a planar base portion and spring elements extending therefrom, the measurement subsystem disposed on the planar base portion.

56. The system of claim 55 in which the pattern of conductive lands disposed on the planar base portion.

57. The system of claim 55 in which the spring elements extend inwardly from the planar base portion.

58. The system of claim 55 in which the spring elements extend outwardly from the planar base portion.

59. The system of claim 1 in which the sensor is a die made of a material having a coefficient of thermal expansion and the interposer is made of a material which has a coefficient of thermal expansion approximately the same as the coefficient of thermal expansion of the die.

60. The system of claim 59 in which the die is made of silicon or glass and the interposer is made of silicon.

61. The system of claim 1 in which the interposer is made of metal.

62. An interposer for isolating a sensor from its package, the interposer comprising:

a continuous member;

spaced seats extending from the continuous member for supporting the sensor; and

spaced arms extending from the continuous member terminating in tabs which attach the continuous member to the package.

63. The system of claim 62 in which the seats are parallel to the tabs.

64. The system of claim 62 in which the seats are angled.

65. The system of claim 62 in which the continuous member is U-shaped having a base portion and two spaced legs extending from the base portion, the base portion including at least one seat and one tab, each spaced leg also including at least one seat and one tab.

66. The system of claim 65 in which the seats are offset from the tabs.

67. The system of claim 65 in which the seats on the legs are diametrically opposed.

68. The system of claim 62 in which the interposer further includes vibration damping structure.

69. The system of claim 68 in which the vibration damping structure is a coating on the continuous member.

70. An interposer for isolating a sensor from its package, the interposer comprising:

a planar base portion; and

a plurality of spring elements extending from the base portion.

71. The interposer of claim 70 in which the planar base portion is the periphery of the interposer and the plurality of spring elements extend inwardly from the base portion for supporting the sensor thereon.

72. The interposer of claim 71 in which the inwardly extending spring elements are integral with the peripheral base portion.

75. The system of claim 71 in which the inwardly extending spring elements line the same plane as the peripheral base portion.

76. The interposer of claim 70 in which the planar base portion is centrally located to support the sensor thereon and the plurality of spring elements extend outwardly from the centrally located base portion.

77. The interposer of claim 76 in which the outwardly extending spring elements are integral with the central base portion.

78. The interposer of claim 76 in which each outwardly extending spring element includes a tab portion connected to the central base portion and a pair of arms extending from the tab.

79. The interposer of claim 78 in which the arms extend transversely from the tab portion in opposite directions.

80. The interposer of claim 78 further including a channel through the arms and the tab portion.

81. The interposer of claim 80 in which the channel is continuous.

82. The interposer of claim 70 in which the interposer includes a heater.

83. The interposer of claim 82 in which the heater is disposed on the planar base portion.

84. The interposer of claim 83 in which the heater is a pattern of conductive lands disposed on the base portion.

85. The interposer of claim 70 in which the interposer includes a measurement subsystem.

86. The interposer of claim 85 in which the measurement subsystem is a temperature sensor.

87. The interposer of claim 86 in which the temperature sensor includes a pattern of conductive lands disposed on the interposer, the lands made of a material which changes in resistance as a known function of temperature.

88. The interposer of claim 70 further including both a heater and a temperature sensor.

73. The interposer of 71 in which each inwardly extending spring element extends first along a first axis and then turns to extend along a second axis.

74. The interposer of claim 73 in which the first and second axis are orthogonal.

89. A sensor isolation system comprising:

a sensor;

a package for the sensor, the package including a floor and walls upstanding from the floor; and

a compliant interposer disposed on the floor of the package to support and cradle sensor above the floor of the package and interconnecting the sensor with the wall of the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

90. A sensor isolation system comprising:

a sensor;

a package for the sensor, the package including a floor and wall upstanding from the floor; and

a compliant interposer including a peripheral base portion with inwardly directed spring elements attached to the floor of the package to support the sensor above the floor of the package and interconnecting the sensor with the wall of the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

91. A sensor isolation system comprising:

a sensor;

a package for the sensor, the package including a floor and wall upstanding from the floor; and

a compliant interposer including a central base portion with outwardly extending spring elements attached to the floor of package to support the sensor above floor and interconnecting the sensor with the wall of the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

92. A sensor isolation system comprising:

a sensor;

a package for the sensor, the package including a floor and wall upstanding from the floor; and

a compliant interposer including a plurality of spring members to support and cradle the sensor above the floor of the package, the compliant interposer interconnecting the sensor with the wall of the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

93. A sensor isolation system comprising:

a sensor;

a package for the sensor, the package including a floor and wall upstanding from the floor; and

a U-shaped compliant interposer having a base portion and two spaced legs extending from the base portion, the base portion including at least one seat and one tab, each spaced leg also including at least one seat and one tab, the compliant interposer cradling the sensor above the floor of the package and interconnecting the sensor with the wall of the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

94. A sensor isolation system comprising:

a sensor;

a package for the sensor, the package including a floor and wall upstanding from the floor; and

a compliant interposer integral with the package to support and cradle the sensor above the floor of package and interconnecting the sensor with the wall of the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.

95. A sensor isolation system comprising:

a sensor;

a package for the sensor; and

means disposed between the sensor and the package for interconnecting the sensor to the package to isolate the sensor from thermal and mechanical stresses and yet at the same time providing a physical interconnect between the sensor and the package.