Sensor system

• US 7,327,003 B2
• Filed: 02/15/2005
• Issued: 02/05/2008
• Est. Priority Date: 02/15/2005
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Zhang, Xin, Judy, Michael W., Brosnihan, Timothy J., Martin, John R.
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US11/058,483
• Publication Number:
  US 20060180896A1
• Time in Patent Office: 1,085 Days
• Field of Search: 257/414, 257/415
• US Class Current: 257/414
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B81B 3/0018 Structures acting upon the moving or flexible element for transforming energy into mechanical movement or vice versa, i.e. actuators, sensors, generators
• CPC Class Codes: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping
• CPC Class Codes: H01G 5/40 Structural combinations of variable capacitors with other electric elements not covered by this subclass, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

Rather than increasing the mass of the structure, the structure in a sensor system suspends its substrate from some mechanical ground. Motion of the substrate relative to the mechanical ground thus provides the movement information. To those ends, the sensor system includes a base, a substrate, and a flexible member suspended from at least a portion of the substrate. At least a portion of the flexible member is capable of moving relative to at least a portion of the substrate. In addition, the flexible member is secured to the base, thus causing the substrate to be movable relative to the base. Moreover, the mass of the substrate is greater than the mass of the flexible member. The substrate and flexible member are configured to interact to produce a motion signal identifying movement of the base.

Claims

1. A sensor system comprising:

a base;

a substrate; and

a flexible member suspended from at least a portion of the substrate, at least a portion of the flexible member being capable of moving relative to at least a portion of the substrate, the substrate having a substrate mass, the flexible member having a flexible member mass, the substrate mass being greater than the flexible member mass,

the substrate and flexible member being configured to interact to produce a motion signal identifying movement of the base,

the flexible member being secured to the base, the substrate being movable relative to the base,

wherein the substrate includes a conductor that cooperates with the flexible member to form a varying capacitor, the capacitance of the varying capacitor changing as the substrate moves relative to the flexible member.

2. The sensor system as defined by claim 1 wherein the portion of the flexible member is capable of moving relative to the base.

3. The sensor system as defined by claim 1 wherein the substrate includes an in-situ cap.

4. The sensor system as defined by claim 1 wherein the substrate includes circuitry for detecting motion of the substrate relative to the base.

5. The sensor system as defined by claim 1 further including a conductive boss coupling the flexible member to the base.

6. The sensor system as defined by claim 1 further including circuitry on the substrate for converting changes in the varying capacitance to a signal identifying movement of the base.

7. The sensor system as defined by claim 1 wherein the base includes a semiconductor, an integrated circuit, a package, or a circuit board.

8. The sensor system as defined by claim 1 further including a plurality of additional flexible members suspended from the substrate, the additional flexible members each having an additional flexible member mass, the sum total of the flexible member mass and all additional flexible member masses being less than the substrate mass.

9. The sensor system as defined by claim 1 wherein the substrate and flexible member are a part of a MEMS chip, the flexible member mounting the MEMS chip to the base.

10. The sensor system as defined by claim 1 wherein the flexible member is flip-chip secured to the base.

11. The sensor system as defined by claim 1 wherein the flexible member has a substantially angle-less outer boundary.

12. The apparatus as defined by claim 1 wherein the motion signal is used to measure acceleration.

13. The sensor system as defined by claim 1 wherein the motion signal is used as a switch.

14. The sensor system as defined by claim 1 further including a pressure sensor on the substrate.

15. A method of producing a sensor system, the method comprising:

forming a MEMS chip having a flexible member suspended from at least a portion of a substrate, at least a portion of the substrate being capable of moving relative to at least a portion of the flexible member, the flexible member having a flexible member mass, the substrate having a substrate mass, the substrate mass being greater than the flexible member mass; and

coupling the flexible member with a base so that the substrate is movable relative to the base,

wherein the flexible member includes a movable portion relative to the substrate, the flexible member also including a stationary portion relative to the substrate.

16. The method as defined by claim 15 further comprising forming a pressure sensor on the MEMS chip.

17. The method as defined by claim 15 wherein the flexible member has a surface facing the base, the method further comprising:

forming a mourning member on the flexible member surface facing the base,

coupling comprising securing the mounting member to the base.

18. The method as defined by claim 15 further wherein forming includes forming circuitry on the substrate before suspending the flexible member from at least a portion of the substrate.

19. The method as defined by claim 15 further comprising forming a conductive plate on the substrate, the conductive plate and flexible member together forming a varying capacitor.

20. The method as defined by claim 15 further comprising forming a conductive plate on the substrate, the conductive plate and base together forming a varying capacitor.

21. A sensor system comprising:

a base;

a substrate; and

means for movably securing the substrate to the base, the securing means being suspended from at least a portion of the substrate, at least a portion of the securing means being capable of moving relative to the substrate, the substrate having a substrate mass, the securing means having a securing means mass, the substrate mass being greater than the securing means mass,

movement of the substrate producing a motion signal identifying movement of the base,

the substrate being movable relative to the base,

wherein the base includes a circuit board or a package.

22. The sensor system as defined by claim 21 wherein the securing means includes a flexible member.

23. The sensor system as defined by claim 22 wherein the securing means includes a flexible member and a conductive boss, the boss coupling the flexible member to the base.

24. The sensor system as defined by claim 21 wherein the substrate and securing means include means for sensing motion of the substrate relative to the base.

25. A sensor system comprising:

a base;

a substrate; and

a flexible member suspended from at least a portion of the substrate, at least a portion of the flexible member being capable of moving relative to at least a portion of the substrate, the substrate having a substrate mass, the flexible member having a flexible member mass, the substrate mass being greater than the flexible member mass; and

a plurality of additional flexible members suspended from the substrate, the additional flexible members each having an additional flexible member mass, the sum total of the flexible member mass and all additional flexible member masses being less than the substrate mass,

the substrate and flexible member being configured to interact to produce a motion signal identifying movement of the base,

the flexible member being secured to the base, the substrate being movable relative to the base.

26. The sensor system as defined by claim 25 wherein the substrate includes a conductor that cooperates with the flexible member to form a varying capacitor, the capacitance of the varying capacitor changing as the substrate moves relative to the flexible member.