# US 11,306,388 B2 · Sputtering targets and devices including Mo, Nb, and Ta, and methods

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- Number: US 11,306,388 B2
- Document ID: US11306388B2
- Status: Granted
- Kind: B2
- Application number: 16/115,648
- Filed: 2018-08-29
- Published: 2019-02-28
- Granted: 2022-04-19
- Earliest claimed: 2015-01-12
- Assignees: H.C. Starck GmbH
- Applicants: H.C. Starck Inc.
- Inventors: Shuwei Sun; Gary Alan Rozak; Qi Zhang; Barbara Cox; Yen-Te Lee
- Web page: https://patentgrep.com/patent/US11306388B2

## CPC

- C23C 14/22: characterised by the process of coating
- C22C 27/04: Alloys based on tungsten or molybdenum
- C23C 14/083: {of refractory metals or yttrium}
- C23C 14/14: Metallic material, boron or silicon
- C23C 14/165: {by cathodic sputtering}
- C23C 14/3407: {Cathode assembly for sputtering apparatus, e.g. Target}
- C23C 14/3414: {Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy}
- C23C 14/5873: {Removal of material}
- H01J 37/3429: {Plural materials}
- C22C 21/00: Alloys based on aluminium
- G06F 2203/04103: Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

Sputtering targets including molybdenum, niobium and tantalum are found to be useful for sputtering films for electronic devices. Sputtering targets with about 88 to 97 weight percent molybdenum show improved performance, particularly with respect to etching, such as when simultaneously etching an alloy layer including the Mo, Nb, and Ta, and a metal layer (e.g., an aluminum layer). The targets are particularly useful in manufacturing touch screen devices.

## Claims

### Claim 1

A method of fabricating an electronic device, the method comprising:
sputtering a sputtering target to form an alloy layer over a substrate, wherein (a) the sputtering target comprises (i) about 88 atomic percent to about 97 atomic percent molybdenum, (ii) about 2 atomic percent to about 8 atomic percent niobium, and (iii) about 0.5 atomic percent to about 5 atomic percent tantalum, and (b) the alloy layer comprises molybdenum, niobium, and tantalum;
forming a metal layer over the alloy layer, wherein the metal layer comprises at least one of Al, Fe, Cu, Ag, Au, W, Zn, Pt, or Sn;
after forming the metal layer, sputtering the sputtering target in a presence of oxygen to form an oxide layer over the alloy layer and the metal layer, wherein the oxide layer comprises molybdenum, niobium, tantalum, and oxygen, and wherein the alloy layer and the oxide layer have the same atomic ratio of Mo:Ta, Nb:Ta, and Mo:Nb; and
with a PAN etchant comprising phosphoric acid, acetic acid, nitric acid, and water, etching away portions of the alloy layer, the metal layer, and the oxide layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the sputtering target comprises about 0.7 atomic percent to about 4 atomic percent tantalum.

### Claim 3 (depends on 1)

The method of claim 1, wherein the sputtering target comprises about 89 atomic percent to about 96 atomic percent molybdenum.

### Claim 4 (depends on 1)

The method of claim 1, wherein the sputtering target comprises about 2.8 atomic percent to about 7.6 atomic percent niobium.

### Claim 5 (depends on 1)

The method of claim 1, wherein the sputtering target comprises about 0.7 atomic percent to about 3.7 atomic percent tantalum.

### Claim 6 (depends on 1)

The method of claim 1, wherein the total concentration of the molybdenum, the niobium, and tantalum atoms in the sputtering target is about 95 atomic percent or more.

### Claim 7 (depends on 1)

The method of claim 1, wherein the total concentration of the molybdenum, the niobium, and tantalum atoms in the sputtering target is about 99.8 atomic percent or more.

### Claim 8 (depends on 1)

The method of claim 1, wherein the metal layer comprises Al.

### Claim 9 (depends on 1)

The method of claim 1, wherein the substrate comprises glass or silicon.

### Claim 10 (depends on 1)

The method of claim 1, wherein etching away the portion of the oxide layer and the portion of the alloy layer thereunder comprises etching away the portion of the oxide layer and the portion of the alloy layer thereunder with the PAN etchant in a single etch step.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
forming an input component over the substrate, the input component comprising a plurality of touch sensors; and
forming a transparent cover over the input component.