Force-sensing transducers, accelerometers, rate sensors, methods of forming force-sensing transducers, and methods of forming vibrating-beam force transducers

• US 6,423,564 B1
• Filed: 10/30/2000
• Issued: 07/23/2002
• Est. Priority Date: 08/14/1997
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Sprague, Randy, Hulsing, Rand H. II
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): Simkovic, Viktor
• Application Number:
  US09/702,371
• Time in Patent Office: 631 Days
• Field of Search: 438/50, 438/51, 438/52, 438/53, 738/626.1, 738/623.51, 738/624.73, 738/624.74, 735/141.8, 735/143.2, 735/143.8
• US Class Current: 438/52
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01L 1/183 by measuring variations of frequency of vibrating piezo-resistive material
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends

Abstract

Performance-enhancing, reduced-area metalization adhesion areas in force-sensing transducers are described.

Claims

1. A method of forming a force-sensing transducer comprising:

providing a substrate having a force sensing element defining an area over and within which a conductive layer of material is to be formed;

forming a patterned adhesion layer over less than an entirety of the area; and

forming a conductive layer of material over the area, the conductive layer of material being bonded to the substrate through the patterned adhesion layer in a bonding relationship, wherein the area of bonding is less than the area of said conductive layer.

2. The method of claim 1, wherein the providing of the substrate having the force sensing element comprises etching the substrate to form the force sensing element.

3. The method of claim 2, wherein the substrate includes a proof mass, and the etching of the force-sensing element comprises etching a plurality of vibratable beams joined with the proof mass.

4. The method of claim 1, wherein the providing of the substrate having the force sensing element comprises etching the substrate to form the force sensing element, and forming an oxide layer over the force sensing element.

5. The method of claim 4, wherein the forming of the patterned adhesion layer comprises forming a layer of patterned chrome over the oxide layer.

6. The method of claim 1, wherein the providing of the substrate having the force sensing element comprises etching a plurality of vibratable beams.

7. The method of claim 6, wherein the forming of the patterned adhesion layer comprises shadow masking the adhesion layer onto the beams.

8. The method of claim 6, wherein the forming of the patterned adhesion layer comprises forming a plurality of discrete adhesion layers over one of the vibratable beams.

9. The method of claim 6, wherein the forming of the patterned adhesion layer comprises forming a plurality of discrete adhesion layers over each of the vibratable beams.

10. The method of claim 6, wherein the forming of the patterned adhesion layer comprises forming a plurality of discrete adhesion layers over one of the vibratable beams, one of the discrete adhesion layers being formed over a neutral inflection point of the one beam.

11. The method of claim 1, further comprising exposing the force-sensing transducer to temperature conditions effective to cause a portion not bonded through the patterned adhesion layer to separate from underlying substrate material.

12. A method of forming a vibrating-beam force transducer comprising:

providing a substrate;

etching the substrate sufficient to form a plurality of vibratable beams arranged in a force-sensing configuration;

forming an insulative layer of material over the vibratable beams;

forming an adhesion layer pattern over the vibratable beams, the pattern comprising a plurality of spaced apart pattern components, each beam having three pattern components spaced apart along its length;

forming conductive material over the vibratable beams and the adhesion layer pattern, the conductive material being more fixedly attached to the adhesion layer pattern than to vibratable beam portions not having the adhesion layer pattern thereover; and

temperature cycling the substrate effective to weaken the attachment between the conductive material and the vibratable beam portions not having the adhesion layer pattern thereover.

13. The method of claim 12, wherein the etching also comprises etching a proof mass, the proof mass and the vibratable beams being arranged as an acceleration sensor.

14. The method of claim 12, wherein the forming of the adhesion layer pattern comprises shadow masking the adhesion layer pattern onto the vibratable beams.

15. The method of claim 12, wherein the adhesion layer pattern comprises chrome and the conductive material comprises gold.