Efficient method of making micro-miniature switch device

• US 6,365,442 B1
• Filed: 10/04/2000
• Issued: 04/02/2002
• Est. Priority Date: 10/04/2000
• Status: Expired due to Fees

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Roth, Thomas J., Berenz, John Joseph, Tran, Dean, Rochin, Luis M., DePace, Ronald A.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Nhu, David
• Application Number:
  US09/679,582
• Time in Patent Office: 545 Days
• Field of Search: 438/26, 438/51, 438/48, 438/64, 438/128, 438/133, 438/270, 438/106, 438/942, 438/943, 438/947
• US Class Current: 438/128
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 2203/0338 Channels
• CPC Class Codes: B81C 1/00396 Mask characterised by its composition, e.g. multilayer masks
• CPC Class Codes: B81C 2201/0107 Sacrificial metal
• 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 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

A method of making a micro-miniature switch device (10), which has at least one member (68) movable relative to a substrate (12) upon which the device is provided, includes providing a layer of sacrificial non-photolithography material upon a stratum connected to the substrate. A template is provided via photolithographing step that uses a photoresist material upon a stratum connected to the substrate. A layer is provided to include at least a portion of the movable member. The photoresist material and the sacrificial non-photolithography material are removed using photoresist developer. Preferably, at least two photolithography process steps utilize a single photolithographic mask. Also preferably, substrate material is removed to create a recess and at least one channel into the substrate, wherein the channel intersects the recess. At least a portion of the movable member is provided at a location within the recess and at least a portion of the movable member is provided at a location within the channel.

Claims

1. A method of making a micro-miniature switch device that has at least one member movable relative to a substrate upon which the device is provided, said method comprising:

providing a layer of sacrificial non-photolithography material upon a stratum connected to the substrate;

photolithographing a photoresist material upon a stratum connected to the substrate to provide a template;

providing a layer to comprise at least a portion of the movable member; and

removing the photoresist material and the sacrificial non-photolithography material using photoresist developer.

2. A method as set forth in claim 1, wherein step of providing a layer of sacrificial non-photolithography material includes providing aluminum as the sacrificial non-photolithography material.

3. A method as set forth in claim 1, wherein step of providing a layer of sacrificial non-photolithography material includes providing copper as the sacrificial non-photolithography material.

4. A method as set forth in claim 1, wherein step of providing a layer to comprise at least a portion of the movable member includes providing material to define at least one contact portion of the movable member that is engagable with a portion of the device fixed to the substrate upon movement of the movable member.

5. A method as set forth in claim 1, including at least two photolithography process steps that utilize a single photolithographic mask.

6. A method as set forth in claim 5, wherein said two process steps that utilize a single photolithographic mask include a photolithography step prior to deposition of a sacrificial layer and a photolithography step after the deposition of the sacrificial layer.

7. A method as set forth in claim 1, including creating a recess into the substrate and providing at least a portion of the movable member at a location within the recess.

8. A method as set forth in claim 7, wherein said step of creating the recess into the substrate includes removing substrate material.

9. A method as set forth in claim 1, including creating a channel that extends into the substrate and providing at least a portion of the movable member at a location within the channel.

10. A method as set forth in claim 9, wherein said step of creating a recess into the substrate includes removing substrate material.

11. A method as set forth in claim 1, including creating a recess and at least one channel into the substrate, the channel intersecting the recess, and providing at least a portion of the movable member at a location within the recess and providing at least a portion of the movable member at a location within the channel.

12. A method as set forth in claim 11, wherein said steps of creating a recess and at least one channel into the substrate includes removing substrate material.

13. A method of making a micro-miniature switch device that has at least one member movable relative to a substrate upon which the device is provided, said method including removing substrate material to create a recess and at least one channel into the substrate, the channel intersecting the recess, and providing at least a portion of the movable member at a location within the recess and providing at least a portion of the movable member at a location within the channel.

14. A method as set forth in claim 13, including providing a layer of sacrificial non-photolithography material upon a stratum connected to the substrate, photolithographing a photoresist material upon a stratum connected to the substrate to provide a template, providing a layer to comprise at least a portion of the movable member, and removing the photoresist material and the sacrificial non-photolithography material using photoresist developer.

15. A method as set forth in claim 14, wherein step of providing a layer of sacrificial non-photolithography material includes providing aluminum as the sacrificial non-photolithography material.

16. A method as set forth in claim 14, wherein step of providing a layer of sacrificial non-photolithography material includes providing copper as the sacrificial non-photolithography material.

17. A method as set forth in claim 14, wherein step of providing a layer to comprise at least a portion of the movable member includes providing material to define at least one contact portion of the movable member that is engagable with a portion of the device fixed to the substrate upon movement of the movable member.

18. A method as set forth in claim 13, including at least two photolithography process steps that utilize a single photolithographic mask.

19. A method as set forth in claim 18, wherein said two process steps that utilize a single photolithographic mask include a photolithography step prior to deposition of a sacrificial layer and a photolithography step after the deposition of the sacrificial layer.

20. A method of making a micro-miniature switch device that has at least one member movable relative to a substrate upon which the device is provided, said method including:

(1) photolithographing a first photoresist material upon a stratum connected to a substrate to provide a template, the first photolithograph step using a photolithographic mask; and

(2) photolithographing a second photoresist material upon the stratum connected to the substrate to provide a template, the second photolithographic step using the same photolithographic mask as the photolithographic mask used for the first photolithographing step.

21. A method as set forth in claim 20, further comprising the step of providing a layer of sacrificial non-photolithography material upon a stratum connected to the substrate after the first photolithography step but before the second photolithography step.

22. A method as set forth in claim 21 further comprising the step of providing a layer to comprise at least a portion of the movable member, and removing the second photoresist material and the sacrificial non-photolithography material using photoresist developer.

23. A method as set forth in claim 22, wherein the step of providing a layer of sacrificial non-photolithography material includes providing aluminum as the sacrificial non-photolithography material.

24. A method as set forth in claim 22, wherein the step of providing a layer of sacrificial non-photolithography material includes providing copper as the sacrificial non-photolithography material.

25. A method as set forth in claim 22, wherein the step of providing a layer to comprise at least a portion of the movable member includes providing material to define at least one contact portion of the movable member that is engagable with a portion of the device fixed to the substrate upon movement of the movable member.

26. A method as set forth in claim 20, including creating a recess into the substrate and providing at least a portion of the movable member at a location within the recess.

27. A method as set forth in claim 26, wherein said step of creating the recess into the substrate includes removing substrate material.

28. A method as set forth in claim 26, including creating a channel that extends into the substrate and providing at least a portion of the movable member at a location within the channel.

29. A method as set forth in claim 28, wherein said step of creating a recess into the substrate includes removing substrate material.