# US 11,307,493 B2 · Microlithographic fabrication of structures

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,307,493 B2
- Document ID: US11307493B2
- Status: Granted
- Kind: B2
- Application number: 17/067,526
- Filed: 2020-10-09
- Published: 2021-02-11
- Granted: 2022-04-19
- Earliest claimed: 2016-10-18
- Assignees: Molecular Imprints, Inc.
- Applicants: Molecular Imprints, Inc.
- Inventors: Vikramjit Singh; Kang Luo; Michael Nevin Miller; Shuqiang Yang; Frank Y. Xu
- Web page: https://patentgrep.com/patent/US11307493B2

## CPC

- G03F 7/0002: {Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping}
- B29D 11/00769: {Producing diffraction gratings}
- G03F 7/7035: {Proximity or contact printers}
- 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)
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)

## Abstract

Micro- and nano-patterns in imprint layers formed on a substrate and lithographic methods for forming such layers. The layers include a plurality of structures, and a residual layer having a residual layer thickness (RLT) that extends from the surface of the substrate to a base of the structures, where the RLT varies across the surface of the substrate according to a predefined pattern.

## Claims

### Claim 1

A method of fabricating a variable depth pattern, the method comprising:
dispensing, on a surface of a substrate, an imprint fluid according to a predetermined pattern;
contacting the imprint fluid with a surface of an imprint lithography template such that the imprint fluid fills features in the surface of the imprint lithography template; and
solidifying the imprint fluid into a patterned layer, thereby forming, in the patterned layer:
structures that correspond to the features of the imprint lithography template, and
a residual layer having a residual layer thickness (RLT) that extends from the surface of the substrate to a base of one of the structures, wherein a first RLT of a first portion of the patterned layer is different from a second RLT of a second portion of the patterned layer, wherein an RLT in a region between the first portion and the second portion varies gradually from the first RLT to the second RLT; and
etching the patterned layer and the substrate, wherein a depth of features etched into the substrate varies according to variation in the RLT, wherein the imprint lithography template is a master template and, after etching, the substrate is a sub-master lithography template.

### Claim 2 (depends on 1)

The method of claim 1, wherein dispensing the imprint fluid comprises dispensing the imprint fluid in a pattern of drops, wherein a volume of the drops varies according to the predetermined pattern.

### Claim 3 (depends on 2)

The method of claim 2, wherein the pattern of drops corresponds to a fixed drop density in a predetermined region.

### Claim 4 (depends on 2)

The method of claim 2, wherein the pattern of drops corresponds to a varying drop density in a predefined region.

### Claim 5 (depends on 1)

The method of claim 1, wherein dispensing the imprint fluid comprises dispensing the imprint fluid with a jetting dispense system.

### Claim 6 (depends on 1)

The method of claim 1, wherein the features in the imprint lithography template have a uniform feature depth.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
dispensing, on a surface of a second substrate, a second imprint fluid, a volume of which is substantially uniform across the surface of the substrate; and
contacting the second imprint fluid with a surface of the sub-master lithography template such that the imprint fluid fills features in the surface of the sub-master lithography template, thereby forming, in the second imprint fluid, structures and a residual layer having a RLT that varies in accordance with variations in a dimension of features etched into the sub-master lithography template.

### Claim 8 (depends on 1)

The method of claim 1, wherein the features in the imprint lithography template have a varying feature depth.

### Claim 9 (depends on 1)

The method of claim 1, wherein the predetermined pattern corresponds to a diffraction efficiency output map.

### Claim 10 (depends on 1)

The method of claim 1, wherein the structures are nano-structures.

### Claim 11 (depends on 1)

The method of claim 1, wherein the structures are micro-structures.

### Claim 12 (depends on 1)

The method of claim 1, wherein a difference between the first RLT and the second RLT is between 5 nm and 500 nm.

### Claim 13

A method of patterning an imprint fluid, the method comprising:
dispensing, on a surface of a substrate, the imprint fluid, a volume of which varies across the surface of the substrate according to a predetermined pattern;
contacting the imprint fluid with a surface of an imprint lithography template such that the imprint fluid fills features in the surface of the imprint lithography template, thereby forming, in the imprint fluid, structures and a residual layer having a residual layer thickness (RLT) that extends from the surface of the substrate to a base of one of the structures, wherein the RLT varies across the surface of the substrate according to the volume per unit area of the imprint fluid, wherein a first RLT of a first portion of the patterned layer is different from a second RLT of a second portion of the patterned layer, wherein an RLT in a region between the first portion and the second portion varies gradually from the first RLT to the second RLT;
solidifying the imprint fluid into a patterned layer; and
etching the patterned layer and the substrate, wherein a depth of features etched into the substrate varies according to variation in the RLT, wherein the imprint lithography template is a master template and, after etching, the substrate is a sub-master lithography template.

### Claim 14 (depends on 13)

The method of claim 13, wherein dispensing the imprint fluid comprises dispensing the imprint fluid in a predefined pattern that corresponds to a volume needed to fill the features in the imprint lithography template.

### Claim 15

An optical device comprising:
a substrate; and
a polymer imprint resist on a surface of the substrate, the polymer imprint resist comprising:
a plurality of structures forming a diffraction pattern; and
a residual layer having a residual layer thickness (RLT) that extends from the surface of the substrate to a base of one of the plurality of structures, wherein the RLT varies across the surface of the substrate according to a predefined pattern, wherein a depth of each structure of the plurality of structures varies according to
variation in the RLT, wherein variations in the RLT correspond to a diffraction efficiency mapping of a different diffraction grating having a uniform RLT.

### Claim 16 (depends on 15)

The device of claim 15, wherein the polymer imprint resist is an Ultra Violet light curable Nano-Imprint Lithography (UV-NIL) resist.