Method for making mechanical and micro-electromechanical devices

• US 5,413,668 A
• Filed: 10/25/1993
• Issued: 05/09/1995
• Est. Priority Date: 10/25/1993
• Status: Expired due to Fees

• Current Assignee: University of Michigan
• Original Assignee: Ford Motor Company
• Inventors: Tamor, Michael A., Aslam, Mohammad
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): Pham, Long
• Application Number:
  US08/140,906
• Time in Patent Office: 561 Days
• Field of Search: 156/631, 156/625, 156/656, 156/657, 437/228, 437/229
• US Class Current: 216/2
• CPC Class Codes: C23C 16/04 Coating on selected surface areas, e.g. using masks
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009

Abstract

Methods for making mechanical and micro-electromechanical devices (a) forming a mold having a base and metallic walls defining a molding space therebetween, the base being exposed between the metallic walls and either being capable of or having a nucleating upper surface capable of nucleating the deposition of a structural material which does not nucleate on or adhere to the metallic walls at conditions of deposition; (b) depositing a structural material onto either the nucleating upper surface or base and filling to a predetermined height to form a strong solid body; and (c) removing the metallic walls, leaving free-standing, solid body walls of structural material attached to the base; another embodiment of the method may include step (a) and steps (b) filling the molding space with a diamond-nucleating material; (c) consolidating the diamond-nucleating material so as to form a strong solid body; and (d) removing the metallic walls, and thereby freeing the solid body, by dissolving the metallic walls with an agent, normally a liquid.

Claims

1. A method for making mechanical and micro-electromechanical devices comprising the steps of:

forming a mold having a base and metallic walls defining a molding space therebetween, the base being exposed between the metallic walls and having a nucleating upper surface to nucleate a structural material deposited thereon which does not nucleate on or adhere to the metallic walls; and

depositing a structural material onto the nucleating upper surface and filling to a predetermined height to form a strong solid body.

2. A method as set forth in claim 1 wherein the nucleating upper surface is formed at least seventy percent volume of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof.

3. A method as set forth in claim 1 wherein the structural material is at least seventy percent volume a material selected from a group comprising of diamond, silicon carbide, silicon nitride, and mixtures thereof.

4. A method as set forth in claim 1 wherein depositing the structural material is accomplished by a technique selected from a group comprising of chemical vapor deposition and physical vapor deposition.

8. A method as set forth in claim 1 further comprising, after the step of depositing the structural material, the step of removing the metal walls, leaving free-standing walls of structural material attached to the base.

9. A method as set forth in claim 8 wherein removing the metal walls is accomplished by dissolving the metal walls with an agent.

5. A method for making mechanical and micro-electromechanical devices comprising the steps of:

depositing an electrically-conducting nucleating layer on an electrically-conductive substrate, thereby forming a nucleating upper surface;

applying a layer of radiation-sensitive material onto the electrically-conducting nucleating layer;

removing selected portions of the layer of radiation-sensitive material to expose first areas of the electrically-conducting nucleating layer;

electrodepositing metal onto the first areas of the electrically-conducting nucleating layer;

removing the remaining portions of the radiation-sensitive material, leaving free-standing metallic walls and exposed second areas of the electrically-conducting nucleating layer; and

depositing a structural material onto the electrically-conducting nucleating layer and filling to a predetermined height to form a stronq solid body.

6. A method for making mechanical and micro-electromechanical devices comprising the steps of:

depositing a nucleating layer onto first regions of the upper surface of a substrate, thereby forming a nucleating upper surface;

applying a layer of radiation-sensitive material onto the upper surface of the substrate which includes first regions having the nucleating layer deposited thereon and regions without the nucleating layer deposited thereon;

removing selected portions of the layer of radiation-sensitive material to expose second regions of the upper surface of the substrate, leaving portions of the layer of radiation-sensitive material over the first regions of the upper surface of the substrate;

depositing metal onto the exposed second regions to a height which is less than the height of the layer of radiation-sensitive material;

removing the remaining portions of the radiation-sensitive material, leaving free-standing metallic walls and exposed first regions of the upper surface of the substrate having the nucleating layer deposited thereon; and

depositing a structural material onto the upper surface and filling to a predetermined height to form a stronq solid body.

7. A method as set forth in claim 6 wherein the metal is deposited by sputtering a layer of copper onto the exposed second regions and, thereafter, electrodepositing copper onto the sputtered layer.

10. A method for making mechanical and micro-electromechanical devices comprising the steps of:

forming a mold having metallic walls and a base defining a molding space therebetween, the base being exposed between the metallic walls and nucleating a structural material deposited thereon which does not nucleate on or adhere to the metallic walls;

depositing a structural material formed at least seventy volume percent of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof onto the base and filling to a predetermined height to form a strong solid body;

removing the metallic walls, leaving free-standing, solid body walls of structural material attached to the base.

11. A method as set forth in claim 10 wherein depositing the structural material is accomplished by either chemical vapor deposition or physical vapor deposition.

12. A method as set Eorth in claim 10 wherein removing the metallic walls is accomplished by dissolving the metallic walls with acid.

15. A method as set forth in claim 10 wherein the step of forming the mold comprises:

patterning a layer of nucleating material and radiation-sensitive material on an upper surface of the substrate to form exposed areas;

electrodepositing a metal material onto the exposed areas; and

heating the metal material and patterned layer and substrate to remove the radiation-sensitive material and leave deposits of nucleating material.

13. A method for making mechanical and micro-electromechanical devices comprising the steps of:

depositing an electrically-conducting nucleating layer on an electrically-conductive substrate, thereby forming a nucleating upper surface;

applying a layer of radiation-sensitive material onto the electrically-conducting nucleating layer;

removing selected portions of the layer of radiation-sensitive material to expose first areas of the electrically-conducting nucleating layer;

electrodepositing copper onto the first areas of the electrically-conducting nucleating layer;

removing the remaining portions of the radiation-sensitive material, leaving free-standing copper walls and exposed second areas of the electrically-conducting nucleating layer; and

depositing a structural material formed at least seventy volume percent of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof onto the base and filling to a predetermined height to form a strong solid body; and

removing the metallic walls, leaving free-standing, solid body walls of structural material attached to the base.

14. A method for making mechanical and micro-electromechanical devices comprising the steps of:

patterning a nucleating layer onto first regions of the upper surface of a substrate;

applying a layer of radiation-sensitive material onto the upper surface of the substrate which includes first regions having the nucleating layer deposited thereon and regions without the nucleating layer deposited thereon;

removing selected portions of the layer of radiation-sensitive material to expose second regions of the upper surface of the substrate, leaving portions of the layer of radiation-sensitive material over the first regions of the upper surface of the substrate;

depositing copper onto the exposed second regions to a height which is less than the height of the layer of radiation-sensitive material;

removing the remaining portions of the radiation-sensitive material, leaving free-standing copper walls and exposed first regions of the upper surface of the substrate having the nucleating layer deposited thereon;

depositing a structural material formed at least seventy volume percent of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof onto the base and filling to a predetermined height to form a strong solid body; and

removing the metallic walls, leaving free-standing, solid body walls of structural material attached to the base.

16. A method for making mechanical and micro-electromechanical devices comprising the steps of:

depositing an electrically-conducting nucleating layer on an electrically-conductive substrate forming a nucleating upper surface thereon, the nucleating layer formed at least seventy volume percent of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof, applying a layer of radiation-sensitive material onto the electrically-conducting nucleating layer;

removing selected portions of the layer of radiation-sensitive material to expose first areas of the electrically-conducting nucleating layer;

electrodepositing copper onto the first areas of the electrically-conducting nucleating layer;

removing the remaining portions of the radiation-sensitive material, leaving free-standing walls of copper and exposed second areas of the electrically-conducting nucleating layer;

depositing structural material formed at least seventy volume percent of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof onto the exposed second areas of the electrically-conducting nucleating layer and filling to a predetermined height to form a strong solid body; and

removing the copper walls, leaving free-standing solid body walls of structural material attached to the substrate.

17. A method for making mechanical and micro-electromechanical devices comprising the steps of:

depositing a nucleating layer formed at least seventy volume percent of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof onto first regions of the upper surface of a substrate, thereby forming a nucleating upper surface;

applying a layer of radiation-sensitive material onto the upper surface of the substrate which includes first regions having the nucleating layer deposited thereon and regions without the nucleating layer deposited thereon;

removing selected portions of the layer of radiation-sensitive material to expose second regions of the upper surface of the substrate, leaving portions of the layer of radiation-sensitive material over the first regions of the upper surface;

depositing copper onto the exposed second regions to a height which is less than the height of the layer of radiation-sensitive material; and

removing the remaining portions of the radiation-sensitive material, leaving free-standing copper walls and exposed first regions of the upper surface of the substrate having the nucleating layer deposited thereon;

depositing a structural material formed at least seventy volume percent. of a material selected from a group comprised of diamond, silicon carbide, silicon nitride, and mixtures thereof onto the exposed first regions and filling to a predetermined height to form a strong solid body; and

removing the copper walls, leaving free-standing solid body walls of structural material attached to the substrate.

18. A method as set forth in claim 17 wherein the copper is deposited by sputtering a layer of copper onto the exposed second regions and, thereafter, electrodepositing copper onto the sputtered layer.

19. A method for making mechanical and micro-electromechanical devices comprising the steps of:

forming a mold having a base and metallic walls defining a molding space therebetween;

filling the molding space with a diamond-nucleating material;

consolidating the diamond-nucleating material so as to form a strong solid body; and

removing the metallic walls, and thereby freeing the solid body, by dissolving the metallic walls with an agent.

20. A method as set forth in claim 19 wherein the agent which dissolves the metallic walls contains acid.