# US 8,541,860 B2 · Antireflective coating

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- Number: US 8,541,860 B2
- Document ID: US8541860B2
- Status: Granted
- Kind: B2
- Application number: 13/206,131
- Filed: 2011-08-09
- Published: 2011-12-01
- Granted: 2013-09-24
- Earliest claimed: 2005-12-21
- Assignees: Texas Instruments Incorporated
- Applicants: Simon Joshua Jacobs; Duane Scott Dewald; Leigh A. Files; Terry A. Bartlett
- Inventors: Simon Joshua Jacobs; Duane Scott Dewald; Leigh A. Files; Terry A. Bartlett
- Web page: https://patentgrep.com/patent/US8541860B2

## CPC

- G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means}
- G02B 1/115: Multilayers
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Device and method for an antireflective coating to improve image quality in an image display system. A preferred embodiment comprises a first high refractive index layer overlying a reflective surface of an integrated circuit, a first low refractive index layer overlying the first high refractive index layer, a second high refractive index layer overlying the first low refractive index layer, and a second low refractive index layer overlying the second high refractive index layer. The alternating layers of high refractive index material and low refractive index material form an optical trap, allowing light to readily pass through in one direction, but not so easily in a reverse direction. The dual alternating layer topology improves the antireflective properties of the antireflective layer and permits a wide range of adjustments for manipulating reflectivity and color point.

## Claims

### Claim 1

A method for forming an antireflective coating on a semiconductor device, the method comprising:
forming a first high refractive index layer on a reflective surface;
forming a first low refractive index layer on the first high refractive index layer;
forming a second high refractive index layer on the first low refractive index layer; and
forming a second low refractive index layer on the second high refractive index layer;
wherein the forming of at least one of the low refractive index layers comprises forming a first combination layer from a first low refractive index material; and forming a second combination layer from a second low refractive index material;
wherein the first combination layer has a first thickness and the second combination layer has a second thickness; and
wherein the first thickness and the second thickness are dependent upon a desired color point or desired reflectivity.

### Claim 2

A method for forming an antireflective coating on a semiconductor device, the method comprising:
forming a first high refractive index layer on a reflective surface;
forming a first low refractive index layer on the first high refractive index layer;
forming a second high refractive index layer on the first low refractive index layer; and
forming a second low refractive index layer on the second high refractive index layer;
wherein the first high refractive index layer and the second high refractive index layer are formed from a titanium nitride (TiN) film of composition TixNyOz with x, y, and z being integer values and y>x>z; and
wherein the first low refractive index layer and the second low refractive index layer are formed from materials selected from a group consisting of: silicon dioxide (SiO2) and silicon oxynitride (SiON).

### Claim 3 (depends on 2)

The method of claim 2, further comprising forming, on the second low refractive index layer, alternate layers of a high refractive index layer and a low refractive index layer until a desired number of layers is reached.

### Claim 4 (depends on 2)

The method of claim 2, wherein the forming of at least one of the low refractive index layers comprises:
forming a first combination layer from a first low refractive index material; and
forming a second combination layer from a second low refractive index material.