Method of making contact posts for a microelectromechanical device

• US 9,343,242 B2
• Filed: 06/22/2007
• Issued: 05/17/2016
• Est. Priority Date: 06/22/2007
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Liu, Lianjun
• Primary Examiner(s): Vo, Peter DungBa
• Assistant Examiner(s): Carley, Jeffrey T
• Application Number:
  US11/767,413
• Publication Number:
  US 20080314723A1
• Time in Patent Office: 3,252 Days
• Field of Search: 257/644, 257/647, 333/262, 225/83, 438/50, 438/52, 438/455, 29930-832, 298/46, 298/51, 298/74, 296/22, 298/27, 298/30, 298/44, 330/302, 200/181, 310/12.03
• US Class Current: 1/1
• 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 solid contact post for a microelectromechanical device comprising:

providing a first substrate;

forming a solid post protrusion extending from said first substrate by depositing a thin film on said first substrate and selectively removing a portion of said thin film from said first substrate to form said solid post protrusion from the non-removed portion of said thin film, wherein said solid post protrusion is in direct contact with the first substrate such that there is no gap or other material between the first substrate and the solid post protrusion;

shaping said solid post protrusion to acquire a rounded shape; and

producing a solid contact post exhibiting said rounded shape by overlying said solid post protrusion with a portion of a signal line, said produced solid contact post having no internal cavity formed therein and having no gaps formed in said portion of said signal line overlying said solid post protrusion, said produced solid contact post serving with a selectively contactable conductive trace to actuate the microelectromechanical device;

providing a second substrate;

forming a cantilever beam structure on said second substrate, said cantilever beam structure having the conductive trace positioned thereon; and

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

2. A method as claimed in claim 1 wherein:

said removing operation comprises etching said thin film; and

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

3. A method as claimed in claim 1 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 solid post protrusion acquires said rounded shape.

4. A method as claimed in claim 1 wherein said removing and shaping operations comprise performing an isotropic etch process on said thin film so that said solid post protrusion acquires said rounded shape.

5. 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 solid post protrusion.

6. A method as claimed in claim 1 further comprising producing said solid contact post with said rounded shape in absence of forming any sacrificial layer.

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

forming a second solid post protrusion extending from said first substrate;

shaping said second solid post protrusion to acquire said rounded shape;

constructing an output signal line, a portion of said output signal line overlying said second solid post protrusion to produce a second solid contact post exhibiting said rounded shape, said portion of said output signal line in combination with said second solid post protrusion producing said second solid contact post having no internal cavity formed therein and having no gaps formed in said portion of said output signal line overlying said second solid post protrusion wherein said conductive trace is selectively contactable with said first and second solid contact posts to actuate said microelectromechanical device.

8. A method as claimed in claim 1 wherein said first substrate includes a first surface and a second surface, said solid contact post is formed on said first surface, and said method further comprises constructing an integrated circuit on said second surface of said first substrate following said coupling operation.

9. A method as claimed in claim 1 wherein said first substrate includes a first surface and a second surface, said solid contact post is formed on said first surface, and said method further comprises constructing an integrated circuit on said second surface of said first substrate following construction of said solid contact post on said first surface.

10. A method as claimed in claim 9 wherein said constructing said integrated circuit comprises forming at least one said integrated circuit on said second surface of said first substrate using a semiconductor process technology, said at least one said integrated circuit including at least one of a passive device and an active device.

11. A method as claimed in claim 7 wherein said first substrate is substantially planar and said method further comprises concurrently forming said first and second solid post protrusions on said substantially planar substrate.

12. A method as claimed in claim 7 further comprising:

forming a third solid post protrusion extending from said first substrate;

shaping said third solid post protrusion to acquire a rounded shape; and

constructing an electrode, a portion of said electrode overlying said third solid post protrusion to produce a solid electrode post exhibiting said rounded shape, said portion of said electrode in combination with said third solid post protrusion producing said solid electrode post having no internal cavity formed therein and having no gaps formed in said portion of said electrode overlying said solid electrode post.