# US 7,608,194 B2 · Photonic structures, devices, and methods

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- Number: US 7,608,194 B2
- Document ID: US7608194B2
- Status: Granted
- Kind: B2
- Application number: 11/774,397
- Filed: 2007-07-06
- Published: 2008-01-17
- Granted: 2009-10-27
- Earliest claimed: 2004-01-12
- Assignees: Hewlett-Packard Development Company, L.P.
- Inventors: James Stasiak; David Champion; Kevin Peters; Donald J. Coulman; Tony S. Cruz-Uribe
- Web page: https://patentgrep.com/patent/US7608194B2

## CPC

- G02B 6/1225: {comprising photonic band-gap structures or photonic lattices}
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- B82Y 40/00: Manufacture or treatment of nanostructures
- G03F 7/0002: {Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- 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)

## Abstract

Photonic crystal structures are made by a method including steps of providing a substrate, depositing at least one planar layer to form a stack, each planar layer of the stack comprising two or more sublayers having different sublayer refractive indices, depositing a hard mask material, depositing an imprintable material over the hard mask material, patterning the imprintable material by imprinting an array of depressions, and directionally etching at the depressions a regular array of openings through the hard mask material and the stack.

## Claims

### Claim 1

A method for making a photonic periodic structure, the method comprising the steps of:
a) providing a substrate;
b) depositing at least one planar layer comprising two or more sublayers having different sublayer refractive indices;
c) depositing a chemical-mechanical-polishing (CMP) stop layer;
d) depositing a resist layer;
e) patterning the resist layer by nano-imprint lithography to impress recesses into the resist layer in accordance with a desired periodicity;
f) directionally etching to remove resist from the recesses in the resist layer, whereby first openings are formed in the resist layer;
g) depositing a hard mask material over the resist layer and into the first openings;
h) removing the resist, while leaving a periodic pattern of hard mask material only where previously deposited in the first openings;
i) selectively etching through the at least one planar layer in accordance with the periodic pattern of hard mask material to form second openings, whereby the photonic periodic structure is formed.

### Claim 2 (depends on 1)

The method of claim 1, further comprising the step of:
j) depositing a dielectric material, at least filling the second openings and forming a surface.

### Claim 3 (depends on 2)

The method of claim 2, wherein the dielectric material has a refractive index differing from the refractive indices of the sublayers of the at least one planar layer.

### Claim 4 (depends on 2)

The method of claim 2, further comprising the step of:
k) planarizing the surface formed.

### Claim 5 (depends on 1)

The method of claim 1, further comprising: repeating a subset of steps a number of times until a desired total thickness is reached, the subset of steps comprising:
b) depositing at least one planar layer comprising two or more sublayers having different sublayer refractive indices;
c) depositing a chemical-mechanical-polishing (CMP) stop layer;
d) depositing a resist layer;
e) patterning the resist layer by nano-imprint lithography to impress recesses into the resist layer in accordance with a desired periodicity;
f) directionally etching to remove resist from the recesses in the resist layer, whereby first openings are formed in the resist layer;
g) depositing a hard mask material over the resist layer and into the first openings;
h) removing the resist, while leaving a periodic pattern of hard mask material only where previously deposited in the first openings;
i) selectively etching through the at least one planar layer in accordance with the periodic pattern of hard mask material to form second openings, whereby the photonic periodic structure is formed.