MICROMECHANICAL PRESSURE SENSOR DEVICE AND CORRESPONDING MANUFACTURING METHOD

• US 20160341616A1
• Filed: 11/17/2014
• Published: 11/24/2016
• Est. Priority Date: 01/14/2014
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Classen, Johannes
• Granted Patent: US 10,031,038 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/025 Inertial sensors not provided for in B81B2201/0235 - B81B2201/0242
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 7/0061 suitable for fluid transfer from the MEMS out of the package or vice versa, e.g. transfer of liquid, gas, sound
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: H01L 2224/11 Manufacturing methods

Abstract

A micromechanical pressure sensor device and a corresponding manufacturing method. The micromechanical pressure sensor device includes an ASIC wafer, a rewiring system, formed on the front side, which includes a plurality of strip conductor levels and insulating layers situated in between, a structured insulating layer formed above an uppermost strip conductor level, a micromechanical functional layer formed on the insulating layer and which includes a diaphragm area, which may be acted on by pressure, above a recess in the insulating layer as a first pressure detection electrode, and a second pressure detection electrode on the uppermost strip conductor level, formed in the recess at a distance from the diaphragm area and is electrically insulated from the diaphragm area. The diaphragm area is electrically connected to the uppermost strip conductor level by one or multiple first contact plugs which are led through the diaphragm area and through the insulating layer.

Claims

1-15. -15. (canceled)

16. A micromechanical pressure sensor device which includes:

an ASIC wafer having a front side and a rear side;

a rewiring system, formed on the front side, the rewiring system including a plurality of strip conductor levels and insulating layers situated in between;

a structured insulating layer formed above an uppermost strip conductor level of the plurality of strip conductor levels;

a micromechanical functional layer which is formed on the insulating layer and which includes a diaphragm area, which may be acted on by pressure, above a recess in the insulating layer as a first pressure detection electrode;

a second pressure detection electrode which is formed in the uppermost strip conductor level in the recess at a distance from the diaphragm area and is electrically insulated from the diaphragm area;

wherein the diaphragm area is electrically connected to the uppermost strip conductor level at least one first contact plug is led through the diaphragm area and through the insulating layer.

17. The micromechanical pressure sensor device as recited in claim 16, wherein a first contact plug is provided which is formed as a circumferential ring.

18. The micromechanical pressure sensor device as recited in claim 16, wherein a cap wafer which includes a pressure access to the diaphragm area is bonded to the micromechanical functional layer.

19. The micromechanical pressure sensor device as recited in claim 16, wherein a cap wafer which includes a pressure access to the diaphragm area is bonded to the uppermost strip conductor level.

20. The micromechanical pressure sensor device as recited in claim 16, wherein the diaphragm area includes a thinned area of the micromechanical functional layer.

21. The micromechanical pressure sensor device as recited in claim 16, wherein bonding balls are formed above the micromechanical functional layer outside the diaphragm area, and are electrically connected via at least one second contact plug to the uppermost strip conductor level, which are led through the micromechanical functional layer and through the insulating layer.

22. The micromechanical pressure sensor device as recited in claim 16, wherein bonding balls which are electrically connected to the uppermost strip conductor level by vias are formed above the insulating layer in an area in which the micromechanical functional layer is removed.

23. A manufacturing method for a micromechanical pressure sensor device, comprising:

providing an ASIC wafer having a front side and a rear side;

forming a rewiring system having a plurality of strip conductor levels and insulating layers situated in between on the front side;

forming a structured insulating layer above an uppermost strip conductor level of the plurality of strip conductor levels, the structured insulating layer having a recess;

bonding a wafer to the structured insulating layer;

thinning the bonded wafer to form a micromechanical functional layer;

structuring a diaphragm area, which may be acted on by pressure, in the micromechanical functional layer above the recess in the insulating layer as a first pressure detection electrode;

forming a second pressure detection electrode, which is electrically insulated from the diaphragm area, in the uppermost strip conductor level at a distance from the diaphragm area in the recess; and

forming at least one first contact plug which is led through the diaphragm area and through the insulating layer, as the result of which the diaphragm area is electrically connected to the uppermost strip conductor level.

24. The manufacturing method as recited in claim 23, wherein the insulating layer includes at least one of an oxide layer and at least one nitride layer, and the bonding takes place at a temperature below 400°

C. by way of a plasma-activated direct bonding process.

25. The manufacturing method as recited in claim 23, wherein a first contact plug is provided which is formed as a circumferential ring.

26. The manufacturing method as recited in claim 23, wherein a cap wafer which has a pressure access to the diaphragm area is bonded to the micromechanical functional layer.

27. The manufacturing method as recited in claim 23, wherein the micromechanical functional layer and the insulating layer are removed from the uppermost strip conductor level in areas, and a cap wafer which has a pressure access to the diaphragm area is subsequently bonded to the uppermost strip conductor level.

28. The manufacturing method as recited claim 23, wherein the micromechanical functional layer is thinned in the diaphragm area.

29. The manufacturing method as recited in claim 23, wherein bonding balls are formed above the micromechanical functional layer outside the diaphragm area, and are electrically connected via one or multiple second contact plugs to the uppermost strip conductor level, which are led through the micromechanical functional layer and through the insulating layer.

30. The manufacturing method as recited in claim 23, wherein the micromechanical functional layer is removed in an area, and bonding balls are formed in the area, above the insulating layer, and are electrically connected to the uppermost strip conductor level by vias.