Three-dimensional (3D) porous device and method of making a 3D porous device

Patent metadata

Field	Value
Publication number	US-9601234-B2
Application number	US-201113978453-A
Country	US
Kind code	B2
Filing date	Jan 6, 2011
Priority date	Jan 6, 2011
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A method of making a three-dimensional porous device entails providing a substrate having a conductive pattern on a surface thereof, and depositing a colloidal solution comprising a plurality of microparticles onto the surface, where the microparticles assemble into a lattice structure. Interstices of the lattice structure are infiltrated with a conductive material, which propagates through the interstices in a direction away from the substrate to reach a predetermined thickness. The conductive material spans an area of the surface overlaid by the conductive pattern. The microparticles are removed to form voids in the conductive material, thereby forming a conductive porous structure having the predetermined thickness and a lateral size and shape defined by the conductive pattern.

First claim

The invention claimed is:

1. A method of making a three-dimensional porous micromechanical device, the method comprising:
providing a substrate having a conductive pattern on a surface thereof, the substrate comprising a patterned portion of the surface covered by the conductive pattern and an unpatterned portion of the surface not covered by the conductive pattern;
after providing the substrate, depositing a colloidal solution comprising a plurality of microparticles onto the surface of the substrate, the microparticles assembling into a lattice structure on the patterned and unpatterned portions of the surface;
infiltrating interstices of the lattice structure with a conductive material, the conductive material propagating through the interstices in a direction away from the substrate to reach a predetermined thickness and spanning an area of the surface overlaid by the conductive pattern;
removing the microparticles to form voids in the conductive material, thereby forming a conductive porous structure having the predetermined thickness and a lateral size and shape of the conductive pattern, and
removing only a portion of the substrate to expose an underside of the conductive pattern,
thereby forming the three-dimensional porous micromechanical device.

2. The method of claim 1 , wherein the infiltrating comprises electrodepositing the conductive material using the conductive pattern as an electrode.

3. The method of claim 1 , wherein, prior to depositing the colloidal solution, a difference in surface charge between the conductive pattern and the unpatterned portion of the surface is reduced.

4. The method of claim 3 , wherein reducing the difference in surface charge entails attaching molecules to at least one of the conductive pattern and the unpatterned portion of the surface, thereby functionalizing the surface.

5. The method of claim 4 , wherein the unpatterned portion comprises silica, the conductive pattern comprises gold, and the molecules comprise sodium 3-mercapto-1-propanesulfonate, the molecules being attached to the conductive pattern to render the gold negatively-charged.

6. The method of claim 1 , wherein the conductive material comprises at least a first conductive material and a second conductive material on the first conductive material, the conductive material thereby comprising multiple conductive layers in the direction away from the substrate, the interstices of the lattice structure being infiltrated with the first conductive material to a first thickness and with the second conductive material to a second thickness.

7. The method of claim 6 , wherein the conductive material includes multiple conductive materials up to an n th conductive material, where n is an integer of 3 or greater.

8. The method of claim 1 , further comprising removing a portion of the conductive material from the voids to expand the voids of the conductive porous structure.

9. The method of claim 1 , further comprising directing additional material into the voids to deposit one or more layers of the additional material onto the conductive material, thereby partially filling the voids of the conductive porous structure.

10. The method of claim 9 , further comprising removing substantially all of the conductive material to form a hollow particle framework comprising the additional material.

11. The method of claim 9 , wherein the one or more layers of additional material comprise a thickness of between about 2 microns and about 100 microns.

12. The method of claim 1 , further comprising, after infiltrating the interstices and before removing the microparticles, forming one or more solid layers of material on a top surface of the lattice structure.

13. The method of claim 1 , further comprising forming one or more solid layers of material on the underside of the conductive pattern.

14. The method of claim 1 , wherein, prior to depositing the colloidal solution, the surface of the substrate is provided with a plurality of the conductive patterns thereon.

15. The method of claim 14 , wherein the interstices are infiltrated with a plurality of conductive materials, each of the conductive materials spanning an area of the surface overlaid by one of the conductive patterns, and wherein the microparticles are removed to form voids in each of the conductive materials, thereby forming a plurality of the conductive porous structures.

16. The method of claim 1 , wherein the three-dimensional porous micromechanical device comprises a structure selected from the group consisting of: cantilever and bridge.

Assignees

• King William P
• Braun Paul V
• Dai Zhenting
• Yu Xindi
• Zhang Hui Gang
• Univ Illinois

Inventors

• King William P
• Braun Paul V
• Dai Zhenting
• Yu Xindi
• Zhang Hui Gang

Classifications

• C25D5/48

  After-treatment of electroplated surfaces · CPC title

• C25D5/02

  Electroplating of selected surface areas · CPC title

• C25D7/00 Primary

  Electroplating characterised by the article coated · CPC title

• B81B2203/0353

  Holes · CPC title

• B05D5/12

  to obtain a coating with specific electrical properties · CPC title