WAFER LEVEL ASSEMBLY OF A MEMS SENSOR DEVICE AND RELATED MEMS SENSOR DEVICE

• US 20140319630A1
• Filed: 04/29/2014
• Published: 10/30/2014
• Est. Priority Date: 04/30/2013
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Conti, Sebastiano, Perletti, Matteo, Carminati, Roberto, Baldo, Lorenzo, Morcelli, Alessandro
• Granted Patent: US 9,628,919 B2
• Time in Patent Office: Days
• US Class Current: 257/416
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence

Abstract

An assembly of a MEMS sensor device envisages: a first die, integrating a micromechanical detection structure and having an external main face; a second die, integrating an electronic circuit operatively coupled to the micromechanical detection structure, electrically and mechanically coupled to the first die and having a respective external main face. Both of the external main faces of the first die and of the second die are set in direct contact with an environment external to the assembly, without interposition of a package.

Claims

1. MEMS sensor device assembly comprising:

a first die having an internal surface and an external surface, a micromechanical detection structure located on the internal surface; and

a second die having an internal surface and an external surface, the second die integrating an electronic circuit operatively coupled to said micromechanical detection structure, the internal surface of the second die coupled to the internal surface of said first die, the external surfaces of the first and second dice being exposed outer surfaces of the assembly, and at least one of the external surfaces being configured to be placed in direct contact with a structure external to the assembly.

2. The assembly according to claim 1, wherein said external surfaces of said first and second dice are in respective parallel planes, and said first and second dice are coupled in a direction that is transverse to said planes.

3. The assembly according to claim 1, wherein said first and second dice are configured to be mechanically and electrically coupled to the structure external to the assembly without interposition of packaging material.

4. The assembly according to claim 1, wherein at least one of the external surfaces of said first and second dice is configured to be coupled directly to a printed circuit board.

5. The assembly according to claim 4, wherein said external surface that is configured to be coupled directly to the printed circuit board includes a first electrical-connection element configured to electrically couple the assembly to said printed circuit board.

6. The assembly according to claim 5, further comprising:

a second electrical-connection element located between said internal surfaces of said first and second dice and electrically coupling said micromechanical detection structure to said electronic circuit;

a conductive through via that extends through one of said first and second dice; and

a third electrical-connection element located between said internal surfaces of said first and second dice and configured to electrically couple to the first electrical-connection elements by the conductive through via.

7. The assembly according to claim 1, comprising a coupling ring between said first and second dice that couples the first and second dice together, the coupling ring surrounding said micromechanical detection structure.

8. The assembly according to claim 1, wherein said second die includes a cavity that is located proximate the micromechanical detection structure.

9. The assembly according to claim 8, wherein the micromechanical detection structure is a first micromechanical detection structure, the assembly further comprising a third die integrating a second micromechanical detection structure, the third die being secured to the internal surface of the second die, housed within said cavity in said second die, and facing, at a distance, said micromechanical detection structure said second micromechanical detection structure being electrically coupled to said electronic circuit.

10. The assembly according to claim 9, wherein said cavity in said second die has side walls, the assembly further comprises conductive paths having respective portions located on the side walls, respectively, and said second micromechanical detection structure in said third die is coupled to said electronic circuit by the conductive paths.

11. The assembly according to claim 10, comprising a fourth die integrating a third micromechanical detection structure, the fourth die secured to the internal surface of the second die and housed within said cavity in said second die, said third micromechanical detection structure being electrically coupled to said electronic circuit.

12. The assembly according to claim 1, wherein said micromechanical detection structure is an acoustic transducer, and includes a substrate of semiconductor material having a first cavity, a membrane suspended over the first cavity, and a rigid plate capacitively coupled to the membrane.

13. The assembly according to claim 12, wherein:

said cavity in the first die is in fluid contact with an environment that is external to the assembly and allows acoustic-pressure waves to enter said assembly;

said second die includes a second cavity located proximate the micromechanical detection structure; and

said first and second cavities forming a front chamber and rear chamber, respectively, of the acoustic transducer.

14. The assembly according to claim 1, wherein said micromechanical detection structure is a pressure sensor, and includes a substrate of semiconductor material having a membrane suspended over a buried cavity;

wherein said pressure sensor further includes elastic elements that couple said membrane to said substrate, said membrane being suspended on one side by a cavity in the first die.

15. The assembly according to claim 1, wherein said first and second dice have external side surfaces that are transverse to said external surfaces and internal surfaces and are configured to be placed in direct contact with an external structure.

16. An electronic apparatus, comprising:

a MEMS sensor device including;

a first die having a first surface, a second surface, and a micromechanical detection structure located on the first surface; and

a second die having a first surface and a second surface, the second die integrating an electronic circuit operatively coupled to said micromechanical detection structure, the first surface of the second die being coupled to the first surface of the first die, the second surface of the first die and the second surface of the second die forming external surfaces of the assembly;

a printed circuit board coupled directly to one of the second surfaces of the first and second dice without the interpositioning of packaging material.

17. The electronic apparatus according to claim 16, wherein the micromechanical detection structure is a pressure sensor that includes a semiconductor substrate, a suspended membrane that is elastically coupled to the substrate, and a rigid electrode that is capacitively coupled to the suspended membrane.

18. The electronic apparatus according to claim 16, wherein the first micromechanical detection structure is a first micromechanical detection structure, wherein the first die includes a recess having a bottom surface formed in the first surface, the electronic apparatus further comprising a third die secured to the bottom surface of the recess of the first die, the third die including a second micromechanical detection structure that is operatively coupled to the electronic circuit of the second die.

19. The electronic apparatus according to claim 16, wherein the electronic apparatus is one of a mobile phone, PDS, notebook, voice recorder, audio player with voice-recording capacity, and hydrophone.