# US 7,326,380 B2 · Surface and site-specific polymerization by direct-write lithography

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- Number: US 7,326,380 B2
- Document ID: US7326380B2
- Status: Granted
- Kind: B2
- Application number: 10/893,543
- Filed: 2004-07-19
- Published: 2005-12-08
- Granted: 2008-02-05
- Earliest claimed: 2003-07-18
- Assignees: Northwestern University
- Inventors: Chad A. Mirkin; Xiaogang Liu; Shouwu Guo
- Web page: https://patentgrep.com/patent/US7326380B2

## CPC

- G03F 7/0002: {Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping}
- G03F 7/2049: {using a cantilever}
- G01Q 80/00: Applications, other than SPM, of scanning-probe techniques (manufacture or treatment of nanostructures B82B3/00; recording or reproducing information using near-field interaction G11B9/12, G11B11/24, G11B13/08)
- H01J 2237/31738: using STM
- Y10S 977/857: including coating
- Y10S 977/882: Assembling of separate components, e.g. by attaching
- Y10S 977/897: Polymerization
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- G01Q: SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Polymeric microstructures and nanostructures can be prepared with use of a tip to pattern a surface. A tip can be used to pattern a structure which can initiate polymerization. The structure can be then exposed to monomer to induce polymerization at the structure. Alternatively, a tip can be used to pattern a surface with a monomer in which the surface is treated with polymerization catalyst so that polymerization occurs at the patterning site. Ring-opening metathesis polymerization can be carried out with use of the tip to control the polymerization. The tip can be a sharp tip as used in for example an atomic force microscope tip. Norbornene types of monomers can be used. Biological macromolecules can be also prepared.

## Claims

### Claim 1

A method of direct-write nanolithography comprising:
a) patterning at least one first nanostructure of a polymerizable compound on a substrate; wherein the patterning is carried out with use of a tip to transport the polymerizable compound to the substrate; and wherein the patterning is a patterning of a plurality of nanostructures which are separated from each other by an average edge-to-edge distance of about a micron or less;
b) adding polymerization catalyst to the nanostructure of polymerizable compound to form a second nanostructure which can initiate the polymerization reaction; and
c) polymerizing monomer on the second nanostructure to form a third polymeric nanostructure;
wherein the first nanostructure, the second nanostructure, and the third nanostructure have a lateral feature which is about 100 nm or less.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the polymerizable compound is an organic monomer.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the polymerizable compound is an organic ethylenically unsaturated monomer.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the polymerizable compound anchors to the substrate.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the polymerizable compound chemisorbs to the substrate or covalently bonds to the substrate.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the polymerizable compound physisorbs to the substrate.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the patterning is carried out with use of a nanoscopic tip to transport the polymerizable compound to the substrate.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the patterning is carried out with use of a scanning microscope tip to transport the polymerizable compound to the substrate.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the patterning is carried out with use of a hollow tip to transport the polymerizable compound to the substrate.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the patterning is a patterning of a plurality of nanostructures which are separated from each other by an average edge-to-edge distance of about a 100 nm or less.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the first nanostructure, the second nanostructure, and the third nanostructure have a lateral feature which is about 100 nm or less.

### Claim 12

A method of direct-write nanolithography comprising:
a) patterning at least one first nanostructure of a polymerizable compound on a substrate; wherein the patterning is carried out with use of a tip to transport the polymerizable compound to the substrate;
b) adding polymerization catalyst to the nanostructure of polymerizable compound to form a second nanostructure which can initiate the polymerization reaction; and
c) polymerizing monomer on the second nanostructure to form a third polymeric nanostructure, wherein the first nanostructure, the second nanostructure, and the third nanostructure have a lateral feature which is about one micron or less.

### Claim 13 (depends on 12)

The method according to claim 12, wherein the first nanostructure, the second nanostructure, and the third nanostructure have a lateral feature which is about 100 nm or less.