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Forming the Contact Surfaces of Micromechanical Switches

IP.com Disclosure Number: IPCOM000050177D
Original Publication Date: 1982-Sep-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Related People

Petersen, KE: AUTHOR

Abstract

A contact fabrication process has been developed which produces a rounded contour on the plated contacting electrode of micromechanical switches. The complete process schedule is shown sequentially in Figs. 1a-1c. 1) Dope a (100) silicon wafer 10 heavily with boron in the regions 12 where a switch is desired. 2) Grow an epitaxial layer 14 over the entire substrate 10 to a thickness of 4 to 10 microns. 3) Deposit an insulating layer 16 to a thickness of 0.5 to 3 microns. 4) Deposit a thin metal film 18, typically Cr-Au, to a thickness of several hundred angstroms. 5) Apply a photoresist layer 20 and electroplate a thicker metal film 22 selectively through holes produced in the photoresist lithographically.

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Forming the Contact Surfaces of Micromechanical Switches

A contact fabrication process has been developed which produces a rounded contour on the plated contacting electrode of micromechanical switches. The complete process schedule is shown sequentially in Figs. 1a-1c. 1) Dope a (100) silicon wafer 10 heavily with boron in the

regions 12 where a switch is desired.

2) Grow an epitaxial layer 14 over the entire substrate 10

to a thickness of 4 to 10 microns.

3) Deposit an insulating layer 16 to a thickness of 0.5 to 3

microns.

4) Deposit a thin metal film 18, typically Cr-Au, to a

thickness of several hundred angstroms.

5) Apply a photoresist layer 20 and electroplate a thicker

metal film 22 selectively through holes produced in the

photoresist lithographically. The thin metallization 18

is used as plating base during this operation. The

structure at this stage is shown in Fig. 1a.

6) Strip the photoresist layer 20.

7) Apply a second photoresist layer (not shown) and use it

as a mask to etch the thin metal 18 into lines 24.

8) Strip this photoresist layer.

9) Apply a third photoresist layer (not shown) and use it

as a mask to etch the insulating layer 16 in the region

26 to define the shape of the cantilever beam

switch element.

10) Strip this photoresist layer.

11) Apply a fourth photoresist layer 28 and remove the

resist in the regions where the contact points will be

located (30) and where the contact bar will be attached

(32). Do not strip this layer yet.

12) Apply a fifth photoresist layer 34 and remov...