Damascene template for directed assembly and transfer of nanoelements

Patent metadata

Field	Value
Publication number	US-10208394-B2
Application number	US-201615180262-A
Country	US
Kind code	B2
Filing date	Jun 13, 2016
Priority date	Nov 8, 2011
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

Damascene templates have two-dimensionally patterned raised metal features disposed on an underlying conductive layer extending across a substrate. The templates are topographically flat overall, and the patterned conductive features establish micron-scale and nanometer-scale patterns for the assembly of nanoelements into nanoscale circuits and sensors. The templates are made using microfabrication techniques together with chemical mechanical polishing. These templates are compatible with various directed assembly techniques, including electrophoresis, and offer essentially 100% efficient assembly and transfer of nanoelements in a continuous operation cycle. The templates can be repeatedly used for transfer of patterned nanoelements thousands of times with minimal or no damage, and the transfer process involves no intermediate processes between cycles. The assembly and transfer processes employed are carried out at room temperature and pressure and are thus amenable to low cost, high-rate device production.

First claim

The invention claimed is:

1. A method of assembling and transferring a two-dimensional patterned assembly of nanoelements onto a flexible polymer substrate, the method comprising the steps of:
(a) providing a nanoelement transfer system and a liquid suspension of nanoelements, the nanoelement transfer system comprising
(i) a nanoelement assembly device for creating a patterned assembly of nanoelements;
(ii) a thermally regulated imprint device for applying pressure between the damascene template and a flexible polymer substrate at a selected temperature above ambient temperature for transfer of said patterned assembly of nanoelements onto said flexible polymer substrate; and
(iii) a damascene template comprising
a substantially planar substrate;
a first insulating layer disposed on a surface of the substrate;
an optional adhesion layer disposed on a surface of the first insulating layer opposite the substrate;
a conductive metal layer disposed on a surface of the adhesion layer opposite the first insulating layer, or disposed on a surface of the first insulating layer opposite the substrate if the adhesion layer is absent;
a second insulating layer disposed on a surface of the conductive metal layer opposite the adhesion layer, or opposite the first insulating layer if the adhesion layer is absent; and
a hydrophobic coating selectively disposed on exposed surfaces of the second insulating layer opposite the conductive metal layer;
wherein the conductive metal layer is continuous across at least one region of the substrate, and within said region the conductive metal layer has a two-dimensional microscale or nanoscale pattern of raised features that interrupt the second insulating layer;
wherein the second insulating layer substantially fills the spaces between said raised features; and
wherein exposed surfaces of the raised features and the exposed surfaces of the second insulating layer are essentially coplanar;

(b) submerging the damascene template in the liquid suspension of nanoelements;
(c) applying a voltage between the conductive metal layer of the submerged damascene template and a counter electrode in the liquid suspension, whereby nanoelements from the suspension are assembled onto the exposed surfaces of the raised features of the conductive metal layer of the damascene template and not onto the exposed surfaces of the second insulating layer of the damascene template, thereby forming a patterned assembly of nanoelements on a surface of the damascene template;
(d) withdrawing the damascene template and attached patterned assembly of nanoelements from the liquid suspension while continuing to apply voltage between the conductive metal layer of a submerged portion of the damascene template and the counter electrode;
(e) drying the withdrawn damascene template; and
(f) contacting the patterned assembly of nanoelements attached to the damascene template with the flexible polymer substrate and applying pressure and heat using the thermally regulated imprint device, whereby the patterned assembly of nanoelements is transferred onto the flexible polymer substrate; wherein the contacting is performed at a temperature above the glass transition temperature of the flexible polymer substrate.

2. The method of claim 1 , wherein during steps (c) and (d) the conductive metal layer of the damascene template is positive, the counter electrode is negative, and the pH of the liquid suspension is adjusted such that the nanoelements have a negative charge.

3. The method of claim 1 , wherein during steps (c) and (d) the conductive metal layer of the damascene template is negative, the counter electrode is positive, and the pH of the liquid suspension is adjusted such that the nanoelements have a positive charge.

4. The method of claim 1 , wherein the voltage applied in steps (c) and (d) is sufficiently high to assemble the nanoelements from the suspension across essentially the entire exposed surface of the raised features of the conductive metal layer of the submerged damascene template.

5. The method of claim 1 , wherein a speed of withdrawing the damascene template in step (d) is sufficiently slow to retain the attached patterned assembly of nanoelements on the surface of the raised features of the conductive metal layer of the damascene template through the withdrawal process.

6. The method of claim 1 , wherein the voltage in steps (c) and (d) is in the range from 1.5 to 7 V and a speed of withdrawing in step (d) is in the range from 1 to 15 mm/min.

7. The method of claim 1 , wherein steps (b) through (f) are repeated one or more times using the same damascene template and one or more additional flexible polymer substrates, whereby a plurality of patterned assemblies of nanoelements are transferred onto the additional flexible polymer substrates.

8. The method of claim 7 , wherein steps (b) through (f) are repeated for a total of about 250 cycles and about 250 flexible polymer substrates are produced, each comprising a substantially identical patterned assembly of nanoelements.

9. The method of claim 8 , wherein the hydrophobic coating of the damascene template is refreshed, followed by performing up to an additional 250 cycles of steps (b) through (f).

Assignees

• Univ Northeastern

Inventors

• Busnaina Ahmed
• Cho Hanchul
• Somu Sivasubramanian
• Huang Jun

Classifications

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• G03F7/0002 Primary

  Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping · CPC title

• C25D15/00

  Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires · CPC title

• B82Y10/00 Primary

  Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic · CPC title

• Y10S977/882

  Assembling of separate components, e.g. by attaching · CPC title