METHOD OF MAKING CONTACT POSTS FOR A MICROELECTROMECHANICAL DEVICE

• US 20080314723A1
• Filed: 06/22/2007
• Published: 12/25/2008
• Est. Priority Date: 06/22/2007
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Liu, Lianjun
• Granted Patent: US 9,343,242 B2
• Time in Patent Office: Days
• US Class Current: 200/335
• CPC Class Codes: B81B 2201/016 having a bridge fixed on two ends and connected to one or more dimples
• CPC Class Codes: B81C 1/00103 Structures having a predefined profile, e.g. sloped or rounded grooves
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 1/06 characterised by the shape or structure of the contact-making surface, e.g. grooved
• CPC Class Codes: H01H 1/20 Bridging contacts for circuit breakers H01H73/045
• CPC Class Codes: H01H 11/04 of switch contacts
• CPC Class Codes: Y10T 29/49105 Switch making
• CPC Class Codes: Y10T 29/49174 Assembling terminal to elongated conductor

Abstract

A device 20 includes a substrate 22 coupled with a substrate 24 such that a volume 32 is formed between the substrates 22, 24. Contact posts 48, 50 on the substrate 22 and a cantilever beam structure 36 on the substrate 24 are located within the volume 32. The cantilever beam structure has a conductive trace 38 that is selectively contactable with the contact posts 48, 50 to yield a microelectromechanical (MEMS) switch within the volume 32. Fabrication methodology for making the contact posts 48, 50 entails forming post protrusions 68, 70 on the substrate 22 and shaping post protrusions 68, 70 so that they acquire a rounded shape. Input and output signal lines 42, 44 are constructed such that respective portions of input and output signal lines 42, 44 overly corresponding post protrusions 68, 70 and take on the shape of post protrusions 68, 70.

Claims

1. A method of making a contact post for a microelectromechanical device comprising:

providing a substrate;

forming a post protrusion extending from said substrate;

shaping said post protrusion to acquire a rounded shape; and

constructing a signal line, a portion of said signal line overlying said post protrusion to produce a contact post.

2. A method as claimed in claim 1 wherein said forming operation comprises:

depositing a thin film on said substrate; and

selectively removing a portion of said thin film from said substrate to form said post protrusion.

3. A method as claimed in claim 2 wherein:

said removing operation comprises etching said thin film; and

said shaping operation comprises heating said thin film following said etching until said post protrusion acquires said rounded shape.

4. A method as claimed in claim 2 wherein:

said removing operation comprises performing a photolithographic process on said thin film; and

said shaping operation comprises heating said thin film following said photolithographic process until said post protrusion acquires said rounded shape.

5. A method as claimed in claim 2 wherein said removing and shaping operations comprises performing an isotropic etch process on said thin film so that said post protrusion acquires said rounded shape.

6. A method as claimed in claim 1 wherein said forming operation comprises utilizing one of a dielectric, a polymer, and a metal thin film to form said post protrusion.

7. A method as claimed in claim 1 further comprising producing said contact post in absence of forming any sacrificial layer.

8. A method as claimed in claim 1 wherein said post protrusion is a first post protrusion, said signal line is an input signal line, said contact post is a first contact post, and said method further comprises:

forming a second post protrusion extending from said substrate;

shaping said second post protrusion to acquire said rounded shape;

constructing an output signal line, a portion of said output signal line overlying said second protrusion to produce a second contact post; and

providing a cantilever beam structure proximate said first and second contact posts, said cantilever beam structure having a conductive trace positioned thereon, said conductive trace being selectively contactable with said first and second contact posts to actuate said microelectromechanical device.

9. A method as claimed in claim 1 wherein said substrate is substantially planar and said method further comprises concurrently forming said first and second post protrusions on said substantially planar substrate.

10. A method as claimed in claim 8 wherein said substrate is a first substrate, and said method further comprises:

providing a second substrate;

forming said cantilever beam structure on said second substrate;

coupling said second substrate with said first substrate to form a volume between said first and second substrates, said first and second contact posts on said first substrate and said cantilever beam structure on said second substrate being located within said volume.

11. A method as claimed in claim 10 wherein said first substrate includes a first surface and a second surface, said first and second contact posts are formed on said first surface, and said method further comprises constructing an integrated device on said second surface of said first substrate following said coupling operation.

12. A method as claimed in claim 8 further comprising:

forming a third post protrusion extending from said substrate; and

constructing an electrode, a portion of said electrode overlying said third post protrusion to produce an electrode post.

13. A method as claimed in claim 1 wherein said substrate includes a first surface and a second surface, said first and second contact posts are formed on said first surface, and said method further comprises constructing an integrated device on said second surface of said first substrate following said forming operation.

14. A device comprising:

a first substrate;

first and second contact posts formed on said first substrate, said first contact post including a first post protrusion, said second contact post having a second post protrusion, each of said first and second post protrusions having a rounded shape, and said first and second contact posts acquiring said rounded shape;

a second substrate coupled with said first substrate to form a volume between said first and second substrates, said first and second contact posts being located within said volume; and

a cantilever beam structure formed on said second substrate within said volume, said cantilever beam structure having a conductive trace positioned thereon, said conductive trace being selectively contactable with said first and second contact posts to yield a microelectromechanical switch within said volume.

15. A device as claimed in claim 14 wherein said first and second post protrusions are formed on said first substrate, and said device further comprises:

an input signal line, a portion of which overlies said first post protrusion to form said first contact post that extends from said input signal line; and

an output signal line, a portion of which overlies said second post protrusion to form said second contact post that extends from said output signal line.

16. A device as claimed in claim 14 wherein said first and second contact posts are formed on a first surface of said first substrate, and said device further comprises an integrated device formed on a second surface of said first substrate, said integrated device being formed on said second surface following formation of said first and second contact posts.

17. A method of making a microelectromechanical systems (MEMS) switch comprising:

providing a substrate;

forming a first post protrusion and a second post protrusion extending from said substrate by depositing a thin film on said substrate and selectively removing a portion of said thin film from said substrate;

shaping said first and second post protrusions so that each of said first and second post protrusions acquires a rounded shape;

constructing an input signal line, a portion of said input signal line overlying said first post protrusion to produce a first contact post;

constructing an output signal line, a portion of said output signal line overlying said second post protrusion to produce a second contact post, said output signal line being spaced apart from said input signal line; and

providing a cantilever beam structure proximate said first and second contact posts, said cantilever beam structure having a conductive trace positioned thereon, said conductive trace being selectively contactable with said first and second contact posts to actuate said MEMS switch.

18. A method as claimed in claim 17 wherein:

said removing operation comprises etching said thin film; and

said shaping operation comprises heating said thin film following said etching until said first and second post protrusions acquire said rounded shape.

19. A method as claimed in claim 17 wherein:

said removing operation comprises performing a photolithographic process on said thin film; and

said shaping operation comprises heating said thin film following said photolithographic process until said first and second post protrusions acquire said rounded shape.

20. A method as claimed in claim 17 further comprising:

providing a second substrate;

forming said cantilever beam structure on said second substrate;

coupling said second substrate with said first substrate to form a volume between said first and second substrates, said first and second contact posts on said first substrate and said cantilever beam structure on said second substrate being located within said volume.