High purity refractory metal powders and their use in sputtering targets which may have random texture

Patent metadata

Field	Value
Publication number	US-10023953-B2
Application number	US-201514681660-A
Country	US
Kind code	B2
Filing date	Apr 8, 2015
Priority date	Apr 11, 2014
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A method for making a sputtering target including steps of encapsulating and hot isostatically pressing at least one mass of metal powder (e.g., tantalum), having a particle size ranging from about 10 to about 1000 μm, with at least about 10 percent by weight of particles having a particle size greater than about 150 μm (for example, about 29 to about 56 percent (e.g., about 35 to about 47 percent) by weight of the particles in the at least one mass of metal powder having a particle size that is larger than 150 microns, but below about 250 μm), for defining at least a portion of a sputtering target body, having an essentially theoretical random and substantially uniform crystallographic texture.

First claim

What is claimed is:

1. A method for making a sputtering target comprising the steps of:
a. encapsulating at least one mass of metal powder that has at least about 95% by weight of particles exhibiting a particle size ranging from about 10 to about 1000 μm, with at least about 10 percent by weight of particles having a particle size greater than about 150 μm, in a container configured for defining at least a portion of a sputtering target body; and
b. hot isostatically pressing the at least one mass of metal powder to form a resulting densified mass having an initial crystallographic texture, while the at least one mass of metal powder is in the container, wherein the hot isostatically pressing step is performed under conditions so that the initial crystallographic texture achieved in the resulting densified mass is an essentially theoretically random and generally uniform crystallographic texture, wherein the method is devoid of any step of altering the initial crystallographic texture substantially throughout the resulting densified mass after the step of hot isostatically pressing and prior to sputtering, and
wherein the method includes a step of making a refractory metal powder using a method comprising the steps of:
a. locating an initial mass of refractory metal powder having an initial content of oxygen in a reactor;
b. locating within the reactor, spaced apart from the initial mass of refractory metal powder, a mass of a scavenging metal, wherein the mass of the scavenging metal and the initial mass of refractory metal powder are not blended together;
c. heating within the reactor to a scavenging temperature for causing at least a portion of the scavenging metal to at least partially vaporize and react with at least a portion of the initial content of oxygen to form a scavenging metal oxide with at least a portion of the scavenging metal; and
d. separating the scavenging metal oxide from the initial mass of refractory metal powder so that a resulting mass of refractory metal powder is formed that has a resulting content of oxygen that is less than the initial content of oxygen, wherein the at least one mass of metal powder comprises at least a portion of the resulting mass of refractory metal powder, and wherein the resulting densified mass (i) has an oxygen content below about 125 PPM, and/or (ii) comprises the scavenging metal in an amount below about 10 PPM.

2. The method of claim 1 , wherein the resulting mass of refractory metal powder comprises at least about 99.95 percent by weight of tantalum.

3. The method of claim 1 , wherein the initial content of oxygen is greater than about 300 ppm by weight.

4. The method of claim 1 , wherein the initial mass of refractory metal powder is in a bed having a depth ranging from about 0.3 cm to about 3.5 cm.

5. The method of claim 1 , wherein the scavenging metal is magnesium, is present in the reactor in the form of flakes, or both.

6. The method of claim 1 , wherein the heating step includes heating in the reactor at a temperature of about 800 to about 1000° C. for a time of about 30 minutes to about 2 hours.

7. A method for making a sputtering target comprising the steps of:
a. making a refractory metal powder using a method comprising the steps of:
1. locating an initial mass of refractory metal powder having an initial content of oxygen in a reactor,
2. locating within the reactor, spaced apart from the initial mass of refractory metal powder, a mass of a scavenging metal, wherein the mass of the scavenging metal and the initial mass of refractory metal powder are not blended together,
3. heating within the reactor to a scavenging temperature for causing at least a portion of the scavenging metal to at least partially vaporize and react with at least a portion of the initial content of oxygen to form a scavenging metal oxide with at least a portion of the scavenging metal, and
4. separating the scavenging metal oxide from the initial mass of refractory metal powder so that a resulting mass of refractory metal powder is formed that has a resulting content of oxygen that is less than the initial content of oxygen;

b. encapsulating the resulting mass of refractory metal powder that has at least about 95% by weight of particles exhibiting a particle size ranging from about 10 to about 1000 μm, with at least about 10 percent by weight of particles having a particle size greater than about 150 μm, in a container configured for defining at least a portion of a sputtering target body; and
c. hot isostatically pressing the resulting mass of refractory metal powder to form a resulting densified mass having an initial crystallographic texture, while the resulting mass of refractory metal powder is in the container, wherein the hot isostatically pressing step is performed under conditions so that the initial crystallographic texture achieved in the resulting densified mass is an essentially theoretically random and generally uniform crystallographic texture, wherein the method is devoid of any step of altering the initial crystallographic texture substantially throughout the resulting densified mass after the step of hot isostatically pressing and prior to sputtering.

8. The method of claim 7 , wherein the method is free of any further thermomechanical processing step.

Assignees

• Starck H C Inc

Inventors

• Hogan Patrick
• Aimone Paul
• Flanigan Joseph
• Hagymasi Marcel
• Haas Helmut

Classifications

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• C22F1/18

  High-melting or refractory metals or alloys based thereon · CPC title

• B22F3/1208

  Containers or coating used therefor · CPC title

• H01J37/3426

  Material · CPC title

• B22F3/02

  Compacting only · CPC title