Process for manufacturing a sensor

• US 5,723,353 A
• Filed: 02/12/1996
• Issued: 03/03/1998
• Est. Priority Date: 02/10/1995
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Lutz, Markus, Schubert, Dietrich, Offenberg, Michael, Muenzel, Horst, Heyers, Klaus, Boehringer, Alexandra
• Primary Examiner(s): Nguyen, Tuan H.
• Application Number:
  US08/599,838
• Time in Patent Office: 750 Days
• Field of Search: 437/52, 437/228, 437/901, 437/927, 437/51, 437/3, 437/921, 148/DIG. 135, 148/DIG. 159
• US Class Current: 438/48
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 3/48 by measuring frequency of generated current or voltage in general G01R23/00
• CPC Class Codes: Y10S 148/135 Removal of substrate
• CPC Class Codes: Y10S 148/159 Strain gauges

Abstract

An acceleration sensor is composed of a three-layer system. The acceleration sensor and conductor tracks are patterned out of the third layer. The conductor tracks are electrically isolated from other regions of the third layer by recesses and electrically insulated from a first layer by a second electrically insulating layer. In this manner, a simple electrical contacting is achieved, which is configured out of a three-layer system.

Claims

1. A method for manufacturing a rate-of-rotation sensor, comprising the steps of:

disposing a second insulating layer between a first silicon layer and a third silicon layer, the second layer being deposited and patterned starting from the first layer, the third layer being deposited in an epitaxy reactor; and

applying an etching mask through which a pattern is etched into the third layer and the first layer, wherein during the etching of the first layer, the second layer serves as the etching mask.

2. A process for manufacturing a rate-of-rotation sensor, comprising the steps of:

arranging a second insulating layer between a first silicon layer and a third silicon layer;

depositing a patterned etch-masking layer on a top side of the third silicon layer, the etch-masking layer having at least one trench extending completely to the third silicon layer and at least one additional trench extending to a point within the etch-masking layer without reaching the third silicon layer;

using the etch-masking layer, etching the first and third silicon layers via the at least one trench to form a pattern;

ablating the masking layer during the etching so that, during the step of etching the first and third silicon layers, the at least one additional trench is driven to the third silicon layer; and

etching the third silicon layer via the at least one additional trench.

3. A method for manufacturing a sensor, comprising the steps of:

providing a first layer;

applying a second layer on the first layer, the second layer being an insulator;

applying a third layer on the second layer;

applying a first patterning layer on the third layer, the first patterning layer having a form of an acceleration sensor;

etching the third layer using the first patterning layer as a mask to form the acceleration sensor from the third layer, the acceleration sensor having a deflectable mass and at least one conductor track;

removing the second layer in an area underneath the deflectable mass; and

removing the first patterning layer.

4. The method according to claim 3, further comprising the step of applying a conductive layer on the at least one conductor track.

5. The method according to claim 3, further comprising the steps of:

after removing the first patterning layer, applying a second patterning layer to the third layer, the second patterning layer having a form of a rate-of-rotation sensor;

using the second patterning layer as a mask, etching at least a portion of the first layer, the second layer, and the third layer to form a vibrational structure of the rate-of-rotation sensor;

whereby the acceleration sensor is located on the vibrational structure.

6. The method according to claim 5, further comprising the steps of:

depositing a passivation layer on the first layer;

removing the passivation layer in an area of the vibrational structure; and

ablating the area of the vibrational structure.

7. A method for manufacturing a sensor, comprising the steps of:

providing a first layer;

applying a second layer on the first layer, the second layer being an insulator;

applying a third layer on the second layer, the third layer being a conductor;

depositing a third patterning layer on the third layer, the third patterning layer being patterned in the form of a vibrational structure of a rate-of-rotation sensor, a comb structure of an acceleration sensor and at least one conductor track;

depositing a fourth patterning layer on the third patterning layer, the fourth patterning layer being patterned in the form of the vibrational structure of the rate-of-rotation sensor;

performing an etching process using the fourth patterning layer as a mask to form the vibrational structure from the second layer and the third layer;

removing the fourth patterning layer;

performing an etching process using the third patterning layer as a mask to form the acceleration sensor from the third layer; and

removing the second layer from an area underneath a deflectable mass of the acceleration sensor.

8. The method according to claim 7, further comprising the step of, before the step of depositing the third patterning layer on the third layer, applying a conductive layer in conformance with a pattern of the at least one conductor track.

9. The method according to claim 7, further comprising the steps of:

depositing a first patterning layer on the first layer;

removing the first patterning layer in the area of the vibrational structure of the rate-of-rotation sensor; and

ablating the first layer.

10. The method according to claim 9, further comprising the steps of:

depositing a second patterning layer on the first patterning layer; and

removing the second patterning layer in the area of the vibrational structure of the rate-of-rotation sensor.

11. The method according to claim 7, further comprising the step of applying a passivation layer to the first layer.