Method for manufacturing a rate-of-rotation sensor

• US 6,117,701 A
• Filed: 08/08/1997
• Issued: 09/12/2000
• Est. Priority Date: 08/09/1996
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Buchan, Nicholas, Lutz, Markus, Laermer, Franz, Offenberg, Michael, Muenzel, Horst, Bischof, Udo
• Primary Examiner(s): DUTTON, BRIAN KEITH
• Application Number:
  US08/907,601
• Time in Patent Office: 1,131 Days
• Field of Search: 73/514.36, 73/514.37, 438/52, 438/53, 257/417, 257/418, 257/419
• US Class Current: 438/52
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type

Abstract

A rate-of-rotation sensor includes a three-layer system. The rate-of-rotation sensor and the conductor traces are patterned out of the third layer. The conductor traces are electrically insulated (isolated) by cutouts from other regions of the third layer and by a second electrically insulating layer from a first layer. Thus, a simple electrical contacting (configuration) is achieved that is patterned out of a three-layer system. Since the same etching process is used for the first and the third layer, an especially efficient manufacturing is possible.

Claims

1. A method for manufacturing a rate-of-rotation sensor having an oscillator structure and being at least partially configured as an acceleration sensor, the rate-of-rotation sensor including a comb-shaped structure, a suspension mount for the oscillator structure and a substrate, the substrate including a first layer, a second insulating layer and a third layer, the method comprising the steps of:

patterning the comb-shaped structure and conductor traces from the third layer;

after patterning the comb-shaped structure, at least partially etching the second insulating layer which is provided underneath the comb-shaped structure;

removing at least a portion of a passivation layer on the first layer in a region where the oscillator structure is to be patterned;

ablating the first layer to a particular thickness using a dry etching process in the region where the oscillator structure is to be patterned; and

patterning the oscillator structure from the first, the second insulating, and the third layers.

2. The method according to claim 1, wherein the conductor traces are securely joined to the second insulating layer and are routed from the comb-shaped structure to the suspension mount.

3. The method according to claim 1, further comprising the step of:

depositing conductive layers on the conductor traces.

4. The method according to claim 1, wherein the substrate is composed of a silicon-on-insulator (SOI) layer system.

5. The method according to claim 4, wherein the first layer is composed of silicon, the second insulating layer is composed of silicon oxide, and the third layer is composed of silicon.

6. The method according to claim 1, wherein the first layer is composed of a silicon-on-insulator (SOI) three-layer system, the second insulating layer is composed of an oxide, and the third layer is composed of a silicon.

7. The method according to claim 6, wherein the first layer is used as at least one of the oxide and an etching barrier.

8. A method for manufacturing a rate-of-rotation sensor having an oscillator structure and being at least partially configured as an acceleration sensor, the rate-of-rotation sensor including a comb-shaped structure, a suspension mount for the oscillator structure and a substrate, the substrate including a first layer, a second insulating layer and a third layer, the method comprising the steps of:

patterning the comb-shaped structure and conductor traces from the third layer;

after patterning the comb-shaped structure, at least partially etching the second insulating layer which is provided underneath the comb-shaped structure;

removing at least a portion of a passivation layer on the first layer, the first layer being a silicon-on-insulator (SOI) three-layer system, in a region where the oscillator structure is to be patterned;

ablating the first layer to a particular thickness using one of a wet-chemical etching process and a dry etching process in the region where the oscillator structure is to be patterned; and

after ablating the first layer, patterning the oscillator structure from the first, the second insulating, and the third layers.

9. The method according to claim 8, wherein the SOI three-layer system includes an oxide being used as an etch barrier for ablating the first layer.

10. The method according to claim 8, wherein the SOI three-layer system includes an oxide being used as an etch barrier for forming trench patterns.

11. The method according to claim 8, wherein the SOI three-layer system includes an oxide being ablated in a proximity of an oscillatory mass.

12. The method according to claim 8, wherein the step of ablating the first layer is performed using the wet-chemical etching process.

13. The method according to claim 12, wherein potassium hydroxide is used in the wet-chemical etching process.

14. The method according to claim 8, wherein the step of ablating the first layer is performed using the dry etching process.