Micro structure for vertical displacement detection and fabricating method thereof

• US 6,739,189 B2
• Filed: 04/15/2002
• Issued: 05/25/2004
• Est. Priority Date: 04/26/2001
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Sang-woo, Jung, Kyu-dong, Lee, Byeung-leul, Cho, Yong-chul
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US10/121,666
• Publication Number:
  US 20020158293A1
• Time in Patent Office: 771 Days
• Field of Search: 734/88, 734/96, 735/140.1, 735/143.5, 735/143.6, 735/143.7, 735/143.8, 257/415, 257/417, 257/418, 257/419
• US Class Current: 73/488
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81C 1/0015 Cantilevers switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration

Abstract

Provided are a structure for detecting a vertical displacement and its manufacturing method. The structure for detecting a vertical displacement includes a body, an inertial mass floated over the body, a plurality of support beams extending from the inertial mass so as to suspend the inertial mass over the body, movable electrodes integrally formed with the inertial mass, and fixed electrodes floated over the body, each being positioned between the neighboring movable electrodes, wherein a vertical length of the movable electrode is different from a vertical length of the fixed electrode. Therefore, the structure and the electrodes can be simultaneously manufactured, thereby making the fabrication process simple. Also, it is possible to manufacture a three-axis accelerometer and a three-axis gyroscope on a single wafer by the same process, to be integrated as a six-axis inertial sensor.

Claims

1. A structure for detecting a vertical displacement comprising:

a body;

an inertial mass floated over the body;

a plurality of support beams extending from the inertial mass so as to suspend the inertial mass over the body;

movable electrodes integrally formed with the inertial mass; and

fixed electrodes floated over the body, each being positioned between the neighboring movable electrodes,

wherein a vertical length of the movable electrode is different from a vertical length of the fixed electrode.

2. The structure as claimed in claim 1, wherein the support beams are torsional members.

3. The structure as claimed in claim 2, wherein the inertial mass has different density between a first side portion thereof and a second side portion thereof so as to make a rotation centered about the support beams.

4. The structure as claimed in claim 3, wherein the vertical lengths of the movable electrodes are shorter than the vertical lengths of the fixed electrodes.

5. The structure as claimed in claim 3, wherein the vertical lengths of the movable electrodes are longer than the vertical lengths of the fixed electrodes.

6. The structure as claimed in claim 1, wherein the support beams are bending members.

7. The structure as claimed in claim 6, wherein the vertical lengths of the movable electrodes located at a first side portion of the inertial mass are longer than the vertical lengths of neighboring fixed electrodes, and the vertical lengths of the movable electrodes located at a second side portion of the inertial mass are shorter than the vertical lengths of neighboring fixed electrodes, the first and second side portions being oppositely positioned centered about the bending members.

8. The structure as claimed in claim 1, wherein the body is made of single crystal silicon wafer.

9. The structure as claimed in claim 1, wherein the body is made of SOI wafer including a silicon substrate, an insulating layer and a silicon layer, the inertial mass is fabricated by etching the silicon layer.

10. The structure as claimed in claim 9, wherein the silicon substrate is made of single crystal silicon or epitaxial growth polysilicon.

11. The structure as claimed in claim 1, wherein the body is made of SOG wafer including glass and silicon layer, the inertial mass is fabricated by etching the silicon layer.