Micro-machined device structures having on and off-axis orientations

• US 6,767,758 B1
• Filed: 06/17/2003
• Issued: 07/27/2004
• Est. Priority Date: 04/28/2003
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Geen, John A.
• Primary Examiner(s): TSAI, H JEY
• Application Number:
  US10/463,652
• Time in Patent Office: 406 Days
• Field of Search: 438/48-61
• US Class Current: 438/48
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81C 1/00626 Processes for achieving a desired geometry not provided for in groups B81C1/00563 - B81C1/00619
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

A micro-machined multi-sensor that provides 1-axis of acceleration sensing and 2-axes of angular rate sensing. A method of fabricating the micro-machined multi-sensor includes depositing a layer of sacrificial material or structural material onto the substrate surface. The deposited layer of sacrificial or structural material is then masked with a predetermined mask pattern formed using a rectilinear grid having multiple horizontal and vertical spacings. The mask pattern defines the functional components of the sensor device. In the event the multi-sensor includes at least one functional component whose alignment on the substrate is critical to the optimal performance of the sensor, the critical component is defined so that its longitudinal axis is substantially parallel to the horizontal or vertical axis of the mask. In the event the multi-sensor includes at least one functional component whose alignment on the substrate surface is not critical to optimal sensor performance, the non-critical component may be defined so that its longitudinal axis is not parallel to the horizontal and vertical axes of the mask.

Claims

1. A method of fabricating a micro-machined device on a substrate, the micro-machined device including at least one first component having a critical physical dimension or alignment on the substrate, and at least one non-critical second component, the method comprising the steps of:

depositing at least one layer onto a surface of the substrate;

masking the deposited layer using a predetermined mask pattern, the mask pattern having first and second mutually orthogonal axes associated therewith, the mask pattern being configured to define respective regions on the deposited layer corresponding to the first and second components of the device, the respective region corresponding to the at least one first component having an associated critical axis oriented substantially parallel to the first or second axis associated with the mask pattern, and the respective region corresponding to the at least one second component having an associated non-critical axis oriented off the first and second axes associated with the mask pattern; and

etching the masked layer to transfer the mask pattern to the layer.

2. The method of claim 1 wherein the depositing step includes depositing the layer onto the substrate surface, the deposited layer comprising at least one layer of sacrificial or structural material.

3. The method of claim 2 further including the step of releasing the layer of structural material by removing the sacrificial material.

4. The method of claim 3 wherein the releasing step includes etching the layer of sacrificial material.

5. The method of claim 1 further including the step of repeating the depositing, masking, and etching steps until the fabrication of the first and second components is completed.

6. The method of claim 1 wherein the masking step further includes the step of forming the predetermined mask pattern using a rectilinear grid.

7. The method of claim 1 wherein the masking step includes masking the deposited layer using the predetermined mask pattern, wherein the critical axis associated with the first component is a longitudinal axis.

8. The method of claim 1 wherein the masking step includes masking the deposited layer using the predetermined mask pattern, wherein the non-critical axis associated with the second component is a longitudinal axis.

9. The method of claim 1 wherein the masking step includes masking the deposited layer using the predetermined mask pattern, wherein the critical axis associated with the first component is oriented substantially on the first or second axis associated with the mask pattern.

10. The method of claim 1 wherein the masking step includes masking the deposited layer using the predetermined mask pattern, wherein the first and second axes associated with the mask pattern correspond to horizontal and vertical axes, respectively, of the mask pattern.

11. The method of claim 10 wherein the masking step includes masking the deposited layer using the predetermined mask pattern, the horizontal and vertical axes of the mask pattern being substantially parallel to horizontal and vertical lines, respectively, of a rectilinear grid associated with the mask pattern.

12. The method of claim 11 wherein the masking step includes masking the deposited layer using the predetermined mask pattern, the respective regions corresponding to the first and second components being defined by the mask pattern with reference to the rectilinear grid.