Sensor device including two sensors embedded in a mold material

• US 7,793,550 B2
• Filed: 08/25/2008
• Issued: 09/14/2010
• Est. Priority Date: 08/25/2008
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Auburger, Albert, Elian, Klaus
• Primary Examiner(s): Allen; Andre J
• Application Number:
  US12/197,623
• Publication Number:
  US 20100043530A1
• Time in Patent Office: 750 Days
• Field of Search: None
• US Class Current: 73/754
• CPC Class Codes: B81B 7/0048 between the MEMS die and the substrate
• CPC Class Codes: B81C 2203/0154 Moulding a cap over the MEMS device
• CPC Class Codes: G01L 19/0092 Pressure sensor associated with other sensors, e.g. for measuring acceleration or temperature G01L9/025, G01L9/045, G01L9/065, G01L9/085, G01L9/105, G01L9/125, G01L19/02, G01L19/04 take precedence; measuring two or more variable G01D21/02; temperature sensors with pressure compensation G01K1/26
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 23/49575 Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 25/16 the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/12044 : OLED
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/1433 : Application-specific integrated circuit [ASIC]
• CPC Class Codes: H01L 2924/1461 : MEMS
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 2924/207 : Diameter ranges

Abstract

A sensor device. One embodiment provides a first sensor having a first sensor surface. The first sensor surface is exposed to allow sensing of a first variable. A second sensor has a second sensor surface. The second sensor surface is sealed to inhibit sensing of the first variable, and a mold material is embedded the first and second sensors.

Claims

1. A device comprising:

a first sensor formed from a silicon wafer, the first sensor having a recess and having a silicon membrane formed from the silicon wafer over the recess, with the membrane forming a first sensor surface, the first sensor surface being exposed to allow sensing of a first variable;

a second sensor formed from another or the same silicon wafer, the second sensor having a recess and having a silicon membrane formed from the silicon wafer over the recess in the respective silicon wafer, with the membrane forming a second sensor surface, the second sensor surface being sealed to inhibit sensing of the first variable; and

a mold material embedding the first and second sensors.

2. The device of claim 1, wherein the first sensor is integrated in a first semiconductor chip and the second sensor is integrated in a second semiconductor chip.

3. The device of claim 1, wherein the first and second sensors are integrated in the same semiconductor chip.

4. The device of claim 1, wherein the first and second sensors are pressure sensors.

5. The device of claim 1, wherein the first and second sensors are gas sensors.

6. The device of claim 1, further comprising an evaluation unit coupled to the first and second sensors.

7. The device of claim 6, wherein the mold material influences a first sensor signal from the first sensor and a second sensor signal from the second sensor, and

wherein the evaluation unit receives the first sensor signal from the first sensor and the second sensor signal from the second sensor and compares the first and second sensor signals and compensates for the influence of the mold material on the first sensor signal using the second sensor signal.

8. The device of claim 7, wherein the evaluation circuit forms the difference of the first sensor signal and the second sensor signal.

9. The device of claim 1, wherein the mold material seals the second sensor surface.

10. The device of claim 1, wherein the first and second sensors are placed over a carrier, which has a recess to expose the first sensor surface.

11. The device of claim 10, wherein the carrier seals the second sensor surface.

12. The device of claim 1, wherein the first and second sensors are identical.

13. The device of claim 1, further comprising:

a first glass wafer attached to the first main surface of the first sensor by anodic bonding; and

a second glass wafer attached to a second main surface of the first sensor by anodic bonding, the second main surface being opposite the first main surface.

14. The device of claim 1, wherein at least one of the silicon membranes comprises doped silicon.

15. A method, comprising:

providing a silicon wafer;

forming a membrane in the silicon wafer by forming a recess in the silicon wafer such that the membrane is positioned over the recess in the silicon wafer, wherein the silicon wafer, the recess, and the membrane form a first sensor and the membrane forms a first sensor surface;

providing a second sensor having a second sensor surface;

placing the first and second sensors in a mold cavity;

covering the first and second sensors with a mold material; and

sealing the second sensor surface.

17. The method of claims 15, wherein the first and second sensors are identical.

18. The method of claim 17, comprising covering the first and second sensors with the mold material such that the first sensor surface remains at least partially exposed to allow sensing of a first variable.

19. The method of claim 18, comprising covering the first and second sensors with the mold material such that the second sensor surface is covered with the mold material.

20. The method of claim 18, comprising depositing an electrically insulating layer on the second sensor surface to inhibit sensing of the first variable.

21. The method of claim 17, comprising applying the mold material by at least one of compression molding, injection molding, powder molding, liquid molding and transfer molding.

22. The method of claim 17, comprising integrating the first sensor in a first semiconductor chip and integrating the second sensor in a second semiconductor chip.

23. The method of claim 17, comprising integrating the first and second sensors in the same semiconductor chip.

24. The method of claim 17, wherein the first and second sensors are pressure sensors.

25. The method of claim 17, wherein the first and second sensors are gas sensors.

26. The method of claim 17, further comprising:

anodic bonding of a first glass wafer to a first main surface of the first sensor; and

anodic bonding of a second glass wafer to a second main surface of the first sensor, the second main surface being opposite the first main surface.

27. The method of claim 17, further comprising:

doping the silicon wafer at the position of the membrane.

16. A device, comprising:

a first sensor having a first sensor surface, the first sensor surface being exposed to allow sensing of a first variable and the first sensor outputting a first sensor signal;

a second sensor having a second sensor surface, the second sensor surface being sealed to inhibit sensing of the first variable and the second sensor outputting a second sensor signal;

a mold material embedding the first and second sensors, wherein the mold material causes mechanical stress in the first and second sensors and wherein the mechanical stress influences the first and second sensor signals; and

an evaluation unit to compare the first and second sensor signals and to compensate for the influence of the mechanical stress on the first sensor signal using the second sensor signal.

28. A method, comprising:

providing a first sensor having a first sensor surface;

providing a second sensor having a second sensor surface, the second sensor surface being sealed;

placing the first and second sensors in a mold cavity;

covering the first and second sensors with a mold material, wherein covering the first and second sensors with the mold material causes mechanical stress in the first and second sensors and influences an output signal of the first sensor and an output signal of the second sensor; and

using the output signal of the second sensor to compensate for the influences of the mold material on the output signal of the first sensor.