Method for producing a torsion spring

• US 6,863,832 B1
• Filed: 07/20/2000
• Issued: 03/08/2005
• Est. Priority Date: 07/21/1999
• Status: Expired due to Fees

• Current Assignee: Litec-LP GmbH
• Original Assignee: Litec-LP GmbH
• Inventors: Wiemer, Maik, Rvrko, Bruno, Billep, Detlef, Breng, Uwe, Hiller, Karla, Handrich, Eberhard
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): CULBERT, ROBERTS P
• Application Number:
  US10/031,957
• Time in Patent Office: 1,692 Days
• Field of Search: 216/2, 216/24, 267/154, 735/041.2, 735/041.4
• US Class Current: 216/2
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: B81C 2201/0133 Wet etching
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01P 15/0888 for indicating angular acceleration

Abstract

A method for producing a silicon torsion spring capable, for example, of reading the rotation rate in a microstructured torsion spring/mass system. The system that is produced achieves a low torsional stiffness compared to a relatively high transverse stiffness in the lateral and vertical directions. The method proceeds from a wafer or wafer composite and, upon suitable mask coverage, a spring with a V-shaped cross section is formed by anisotropic wet-chemical etching which preferably extends over the entire wafer thickness and is laterally delimited only by [111] planes. Two of the wafers or wafer composites prepared in this way are rotated through 180° and joined to one another oriented mirrorsymmetrically with respect to one another, so that overall the desired X-shaped cross section is formed.

Claims

1. A method for producing a torsion spring with low torsional compared to transverse stiffness in the lateral and vertical directions as part of a micromechanical torsion spring/mass system, from two wafers or wafer composites, comprising the steps of:

a) producing a spring extending over the entire thickness of said wafer or wafer composite, said spring having a V-shaped cross section that is laterally delimited by [111] planes on at least one side edge region of each wafer or wafer composite, by anisotropic wet-chemical etching;

then

b) rotating said two wafers or wafer composites through 180°

; and

then

c) joining said two wafers or wafer composites to one another oriented in a mirror-image fashion with respect to one another so that an overall X-shaped torsion spring crosssection is formed in the region of the two V-shaped spring cross sections.

2. A method as defined in claim 1, further including the step of forming an insulating layer on the surface that faces the other wafer or wafer composite during joint process on at least one wafer or wafer composite.

3. A method as defined in claim 2, characterized in that said two wafers or wafer composites are joined to one another by silicon direct bonding.