Micromechanical component with sealed membrane openings and method of fabricating a micromechanical component

• US 20010024711A1
• Filed: 02/27/2001
• Published: 09/27/2001
• Est. Priority Date: 08/27/1998
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Kolb, Stefan, Werner, Wolfgang
• Granted Patent: US 6,541,833 B2
• Time in Patent Office: Days
• US Class Current: 428/138
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• 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: Y10T 428/24331 including nonapertured component

Abstract

The method for producing a micromechanical component includes the following steps: producing a semi-finished micromechanical component; producing openings and forming a cavity; sealing the opening with sealing lids; removing material on the top surface of the first membrane layer, the surface of the first membrane layer being exposed and planarized. The invention also relates to a micromechanical component which can be produced according to the above method and to its use in sensors such as pressure sensors, microphones, or acceleration sensors.

Claims

1. A method of producing a micromechanical component, which comprises the following method steps:

producing a semi-finished micromechanical component comprising a wafer, a first membrane layer, and one or more sacrificial layers supporting the first membrane layer;

forming openings in the first membrane layer;

removing material of the sacrificial layer through the openings to form a cavity;

sealing the openings with sealing covers;

removing material on a top side of the first membrane layer, for exposing the surface of the first membrane layer and planarizing the first membrane layer; and

subsequently applying a second membrane layer on the first membrane layer.

2. The method according to

claim 1

, which comprises forming the openings after or during an application of the first membrane layer.

3. The method according to

claim 1

, wherein the removing step comprises removing sealing material by back etching.

4. The method according to

claim 3

, wherein the back etching step is selected from the group of wet chemical etching and dry etching.

5. The method according to

claim 1

, wherein the sealing step comprises depositing an oxide material on the first membrane layer, heating the oxide material to a temperature at which the deposited oxide material flows and seals the openings, and cooling the oxide material to a temperature at which the oxide material hardens.

6. A micromechanical component, comprising:

a wafer;

at least one sacrificial layer having a cavity formed therein;

a first membrane layer disposed on said sacrificial layer, having a top side and having formed therein at least one membrane opening in a region of said cavity;

a sealing cover sealing said at least one membrane opening and being formed of a different material than said first membrane layer, wherein substantially no skin of a material corresponding to the material of said sealing cover is disposed on said top side of said first membrane layer; and

a second membrane layer disposed directly on said first membrane layer.

7. The micromechanical component according to

claim 6

, wherein said sealing cover if formed of an oxide.

8. The micromechanical component according to

claim 6

, wherein said sealing covers and said first membrane layer together form a substantially flat surface on said top side of said first membrane layer.

9. The micromechanical component according to

claim 6

, wherein said first membrane layer has a thickness in a range from substantially 0.2 μ

m to substantially 20 μ

m.

10. The micromechanical component according to

claim 6

, wherein said first membrane layer and said second membrane layers are formed of the same material.

11. The micromechanical component according to

claim 6

, wherein said second membrane layer has a thickness in a range from substantially 0.01 μ

m to substantially 10 μ

m.

12. An integrated chip, comprising a driver circuit and a micromechanical component according to

claim 6

connected to and cointegrated with said driver circuit.

13. The integrated chip according to

claim 12

, wherein said micromechanical component is a sensor and said driver circuit is an evaluation circuit.

14. A sensor device comprising the micromechanical component according to

claim 6

.

15. The sensor device according to

claim 14

, which comprises a sensor housing and said micromechanical component disposed in said sensor housing.