Acceleration sensor

• US 5,627,317 A
• Filed: 06/06/1995
• Issued: 05/06/1997
• Est. Priority Date: 06/07/1994
• Status: Expired due to Term

• Current Assignee: Astra AB (Astrazeneca PLC), Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Buchholtz, Wolfgang, Lutz, Markus, Offenberg, Michael
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US08/466,841
• Time in Patent Office: 700 Days
• Field of Search: 73/514.32, 73/514.35, 73/514.36, 73/514.38, 73/514.21, 73/514.24, 73/862.626, 361/280, 361/283.1
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

A sensor in which the structure of a movable element is produced from an upper silicon layer of a laminated substrate. Individual regions of the upper layer are insulated from one another by insulation trenches which are bridged by conductor tracks coupled to at least one electrode on the movable element and at least one stationary electrode on the upper layer proximate to the at least one electrode on the movable element.

Claims

1. A sensor for measuring a force or acceleration, comprising:

a laminated substrate including;

an upper silicon layer including a movable element which can be moved due to the force or acceleration and a stationary element,

an underlying layer,

means for insulating the upper silicon layer from the underlying layer, and

electrical supply lines arranged on an upper surface of the upper silicon layer, the electrical supply lines being coupled to the movable and stationary elements; and

a conductor track crossing which includes a region insulated from a remainder of the upper silicon layer, wherein a conductor track lies directly on the insulated region between two contacts and is insulated from the insulated region by means of a surface insulation layer,

wherein;

the upper silicon layer includes insulation trenches which penetrate the upper silicon layer completely, for mutually insulating individual regions of the upper silicon layer, and

the electrical supply lines bridge the insulation trenches between the mutually insulated regions of the upper silicon layer.

2. The sensor according to claim 1, wherein the upper silicon layer is insulated from the underlying layer by means of a p-n junction.

3. The sensor according to claim 1, wherein the upper silicon layer is insulated from the underlying layer by means of an insulation layer between the upper silicon layer and the underlying layer.

4. The sensor according to claim 1, wherein the insulation trenches are filled with a dielectric.

5. The sensor according to claim 4, wherein the insulation trenches are oxidized before being filled with polysilicon.

6. The sensor according to claim 4, wherein the insulation trenches are filled with silicon oxide.

7. The sensor according to claim 1, wherein:

the movable element includes a seismic mass which is movably suspended from springs,

at least one movable electrode is attached to the seismic mass,

at least one fixed electrode is arranged on the stationary element opposite the at least one movable electrode,

the at least one movable electrode and the at least one fixed electrode are insulated from one another, and

a spacing between the at least one movable electrode and the at least one fixed electrode changes when the sensor experiences the acceleration.

8. The sensor according to claim 1, wherein the electrical supply lines connect one of the mutually insulated regions with another one of the mutually insulated regions.