# US 8,540,922 B2 · Laser patterning of a carbon nanotube layer

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- Number: US 8,540,922 B2
- Document ID: US8540922B2
- Status: Granted
- Kind: B2
- Application number: 11/895,756
- Filed: 2007-08-27
- Published: 2009-12-17
- Granted: 2013-09-24
- Earliest claimed: 2007-08-27
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Lynn Sheehan; Kevin Dooley; Rory Jordan
- Inventors: Lynn Sheehan; Kevin Dooley; Rory Jordan
- Web page: https://patentgrep.com/patent/US8540922B2

## CPC

- H10K 71/621: {Providing a shape to conductive layers, e.g. patterning or selective deposition}
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- H10K 10/82: Electrodes
- H10K 85/221: {Carbon nanotubes}
- Y10T 428/24802: Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method of patterning a carbon nanotube layer includes providing a substrate comprising a carbon nanotube layer. A laser beam is generated. The laser beam is directed onto a first surface of the carbon nanotube layer. Relative movement between the laser beam and the first surface is caused, thereby forming at least one cavity feature on the first surface.

## Claims

### Claim 1

A method of patterning a carbon nanotube layer, the method comprising:
providing a substrate comprising a carbon nanotube layer formed on a substrate layer;
generating a laser beam;
directing the laser beam onto a first surface of the carbon nanotube layer; and
causing relative movement between the laser beam and the first surface to selectively remove a portion of the carbon nanotube layer during the relative movement without damaging the substrate layer, thereby forming at least one cavity feature on the first surface.

### Claim 2 (depends on 1)

The method of claim 1, wherein the carbon nanotube layer is substantially transparent.

### Claim 3 (depends on 1)

The method of claim 1, wherein the carbon nanotube layer is less than about 1 micrometer thick.

### Claim 4 (depends on 1)

The method of claim 1, wherein the substrate comprises a carbon nanotube layer formed on the substrate layer by one of a vacuum filtration process, an inkjet process, a spray coating process, or a gravure coating process.

### Claim 5

The method of claim l, and further comprising:
modifying a power of the laser beam to below a threshold value during the relative movement to prevent ablation of the carbon nanotube layer; and
modifying a power of the laser beam to above the threshold value during the relative movement to cause ablation of the carbon nanotube layer and form the at least one cavity feature.

### Claim 6 (depends on 1)

The method of claim 1, wherein the relative movement is caused by a scanning mirror that scans the laser beam across the first surface.

### Claim 7 (depends on 1)

The method of claim 1, wherein the relative movement is caused by a scanning mirror that scans the laser beam across the first surface, and a moving stage that moves the substrate.

### Claim 8 (depends on 1)

The method of claim 1, wherein the laser beam comprises ultraviolet light.

### Claim 9 (depends on 8)

The method of claim 8, wherein the laser beam has a wavelength of 355nm.

### Claim 10 (depends on 1)

The method of claim 1, wherein the laser beam is pulsed at 60kHz.

### Claim 11 (depends on 1)

The method of claim 1, and further comprising:
focusing the laser beam to a 1 to 100 micrometer diameter spot on the first surface.

### Claim 12 (depends on 1)

The method of claim 1, wherein the substrate layer comprises one of silicon, glass, and plastic.

### Claim 13 (depends on 1)

The method of claim 1, wherein the substrate layer comprises polyethylene terephthalate (PET).

### Claim 14 (depends on 1)

The method of claim 1, wherein the substrate layer comprises a hard photocurable resist layer.

### Claim 15 (depends on 14)

The method of claim 14, wherein the resist layer comprises a cured SU8 negative photoresist material.

### Claim 16 (depends on 1)

The method of claim 1, wherein the substrate layer comprises a multi-layer stack.

### Claim 17 (depends on 16)

The method of claim 16, wherein the multi-layer stack includes a patterned carbon nanotube layer.

### Claim 18 (depends on 1)

The method of claim 1, wherein the at least one cavity extends from the first surface to a bottom surface of the carbon nanotube layer.