Silicon-Based MEMS Devices Including Wells Embedded with High Density Metal

Patent metadata

Field	Value
Publication number	US-2016178656-A1
Application number	US-201514695421-A
Country	US
Kind code	A1
Filing date	Apr 24, 2015
Priority date	Dec 22, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

In one aspect, the disclosure is directed to a MEMS device. The MEMS device includes a silicon-based movable MEMS sensor element. The MEMS device also includes a plurality of wells formed into at least one surface of the movable MEMS sensor element. Each well is filled with at least one metal so as to increase the effective mass of the movable MEMS sensor element. The metal may be tungsten or tantalum, or an alloy with tungsten or tantalum.

First claim

1 . A MEMS device comprising:
a silicon-based movable MEMS sensor element; and a plurality of wells formed into at least one surface of the movable MEMS sensor element, wherein each well is filled with at least one metal so as to increase the effective mass of the movable MEMS sensor element.

2 . The MEMS device of claim 1 , wherein the at least one metal includes tungsten or an alloy with tungsten.

3 . The MEMS device of claim 1 , wherein the at least one metal includes tantalum or an alloy with tantalum.

4 . The MEMS device of claim 1 , wherein the at least one metal is between about 20% and about 70% tungsten or tantalum or an alloy with tungsten or tantalum.

5 . The MEMS device of claim 1 , wherein each well is filled with at least one metal so as to increase the effective mass of the movable MEMS sensor element between about 2.5x and about 7.0×.

6 . The MEMS device of claim 1 , wherein the plurality of wells covers between about 20% and about 82% of the surface of the movable MEMS sensor element.

7 . The MEMS device of claim 1 , wherein at least one well has an XY plane view shaped like a clover.

8 . The MEMS device of claim 7 , wherein a length of an edge in the clover is about 6.4 μm and each well is separated from adjacent wells by about 2.0 μm.

9 . The MEMS device of claim 1 , wherein at least one well has an XY plane view shaped like a square.

10 . The MEMS device of claim 9 , wherein each well (1) has a length of about 10.0 μm, (2) has a width of about 10.0 μm, and (3) is separated from adjacent wells by about 2.0 μm.

11 . The MEMS device of claim 9 , wherein each well (1) has a length of about 2.0 μm, (2) has a width of about 2.0 μm, and (3) is separated from adjacent wells by about 2.0 μm.

12 . The MEMS device of claim 1 , wherein at least one well has an XY plane view shaped like a rectangle.

13 . The MEMS device of claim 12 , wherein each well (1) has a length of about 20.0 μm, (2) has a width of about 2.0 μm, and (3) is separated from adjacent wells by about 6.0 μm.

14 . The MEMS device of claim 1 , wherein at least one well has an XY plane view shaped like a circle.

15 . The MEMS device of claim 14 , wherein each well (1) has a diameter between about 2.0 μm and about 10.0 μm and (2) is separated from adjacent wells by about 2.0 μm.

16 . The MEMS device of claim 1 , wherein at least one of:
the movable MEMS sensor element is a proof mass of a MEMS accelerometer; or the movable MEMS sensor element is a resonator mass of a MEMS gyroscope.

17 . The MEMS device of claim 1 , wherein:
the wells extend only partially through the MEMS sensor element; the wells extend completely through the MEMS sensor element; the wells are partially filled with the at least one metal; or the wells are completely filled with the at least one metal.

18 . A method of fabricating a MEMS device, the method comprising:
forming a movable MEMS sensor element; forming a plurality of wells into at least one surface of the movable MEMS sensor element; and filling the wells with at least one metal so as to increase the effective mass of the movable MEMS sensor element.

19 . The method of claim 18 , wherein forming the plurality of wells comprises:
patterning a plurality of shapes on the at least one surface of the movable MEMS sensor element, and etching the at least one surface of the movable MEMS sensor element to form the plurality of wells from the plurality of shapes.

20 . The method of claim 19 , wherein patterning the plurality of shapes comprises:
patterning a plurality of clovers, squares, rectangles, or circles.

Assignees

• Analog Devices Inc

Inventors

• Zhang Xin
• Judy Michael W

Classifications

• H01L21/4814

  Electricity · mapped topic

• G01P15/14 Primary

  by making use of gyroscopes (gyroscopes per se G01C19/00) · CPC title

• G01C19/5769

  Manufacturing; Mounting; Housings · CPC title

• B81B2201/0242

  Gyroscopes · CPC title

• G01P15/0802 Primary

  Details · CPC title