U.S. patent application number 12/101544 was filed with the patent office on 2008-08-07 for material mixture, sputter target and method for producing a sputter target.
This patent application is currently assigned to W.C. HERAEUS GMBH. Invention is credited to Markus SCHULTHEIS, Martin Weigert.
Application Number | 20080187453 12/101544 |
Document ID | / |
Family ID | 37814474 |
Filed Date | 2008-08-07 |
United States Patent
Application |
20080187453 |
Kind Code |
A1 |
SCHULTHEIS; Markus ; et
al. |
August 7, 2008 |
MATERIAL MIXTURE, SPUTTER TARGET AND METHOD FOR PRODUCING A SPUTTER
TARGET
Abstract
A material mixture is produced having a cobalt-based alloy as
the predominant component and an additional component of at least
TiO.sub.x. The material mixture may be formed into a sputter target
by hot pressing.
Inventors: |
SCHULTHEIS; Markus;
(Flieden, DE) ; Weigert; Martin; (Hanau,
DE) |
Correspondence
Address: |
PANITCH SCHWARZE BELISARIO & NADEL LLP
ONE COMMERCE SQUARE, 2005 MARKET STREET, SUITE 2200
PHILADELPHIA
PA
19103
US
|
Assignee: |
W.C. HERAEUS GMBH
Hanau
DE
|
Family ID: |
37814474 |
Appl. No.: |
12/101544 |
Filed: |
April 11, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2006/009766 |
Oct 10, 2006 |
|
|
|
12101544 |
|
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Current U.S.
Class: |
419/19 ;
75/252 |
Current CPC
Class: |
B22F 2998/10 20130101;
B22F 2998/10 20130101; C22C 32/0026 20130101; B22F 9/04 20130101;
B22F 2201/01 20130101; C23C 14/3414 20130101; B22F 3/15
20130101 |
Class at
Publication: |
419/19 ;
75/252 |
International
Class: |
C22C 1/05 20060101
C22C001/05 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2005 |
DE |
10 205 049 328.9 |
Claims
1. A material mixture comprising a cobalt-based alloy as a
predominant component and a component of lesser amount comprising
at least TiO.sub.x, wherein x is the atomic ratio of O to Ti.
2. The material mixture according to claim 1, wherein in the
component TiO.sub.x, x<2.
3. The material mixture according to claim 2, wherein in the
component TiO.sub.x, 1.5<x<1.998.
4. The material mixture according to claim 1, wherein the component
TiO.sub.x is in particle form having a particle size in a range of
0.1 to 50 .mu.m.
5. The material mixture according to claim 1, wherein the mixture
is a mixture of a metallic powder of the cobalt-based alloy and an
oxide powder of the TiO.sub.x.
6. The material mixture according to claim 1, wherein the
cobalt-based alloy is an alloy of cobalt with at least one metal
selected from chromium, platinum, tantalum, and boron.
7. A sputter target produced from a material mixture according to
claim 1.
8. The sputter target according to claim 7, wherein the target has
a density of at least 95% of a theoretical density of the material
mixture.
9. A method for producing a sputter target according to claim 7,
the method comprising mixing a powder of the cobalt-based alloy
with a powder of the TiO.sub.x, and hot-pressing the powder
mixture.
10. The method according to claim 9, wherein the powder mixture is
pressed hot axially or hot isostatically.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of International
Application No. PCT/EP2006/009766, filed Oct. 10, 2006, which was
published in the German language on Apr. 19, 2007, under
International Publication No. WO 2007/042255 A1 and the disclosure
of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a material mixture comprising a
cobalt-based alloy as the predominant component, a sputter target,
and a method of producing the target.
[0003] Material mixtures comprising a cobalt-based alloy as the
predominant component are known, for example from U.S. Pat. No.
6,759,005 or from German published patent application DE 195 08 535
A1. These material mixtures are used, inter alia, to create thin
layers as magnetic function layers, especially in magnetic data
storage technology; or the material mixtures form these layers. Due
to the requirements for a high capacity of these layers, the
requirements on the layer materials are increasing and thus on the
sputter targets, which are used for production of the layers, since
these layers are preferably produced by sputtering.
BRIEF SUMMARY OF THE INVENTION
[0004] The invention is based on the objective of improving the
known material mixtures with regard to their magnetic
properties.
[0005] The objective is achieved by a material mixture having a
cobalt-based alloy as the predominant component, i.e., having a
percentage of more than 50 weight %, which additionally comprises
at least TiO.sub.x as the lesser component. The material mixture
has significantly improved magnetic properties and is thus, as a
thin layer, more suitable for magnetic data storage. Such materials
are preferably deposited as thin layers by a sputter technique.
Particularly good homogeneity in depositing sputter material on a
substrate from a sputter target comprising the material will be
achieved by the oxygen-reduced (sub-stoichiometric, i.e., x<2),
electrically conductive titanium oxide being present as a powder
with a particle size ranging from 0.1 to 50 .mu.m. In the TiO.sub.x
compound, x is preferably between 1.5 and 1.998.
[0006] The material mixture or, respectively, a sputter target
produced therefrom is preferably formed from the oxide powder and a
metallic powder of the cobalt-based alloy. The sputter target
preferably has a density of at least 95% of the theoretical density
of the material. The sputter target is produced such that a powder
of the cobalt-based alloy is mixed with the TiO.sub.x powder, and
the powder mixture is hot pressed. It is here advantageous that the
powder mixture is pressed hot axially or hot isostatically. The
material mixtures according to the invention will result in storage
media of very high capacity. They have a TiO.sub.x percentage of
preferably 15 mol % maximum.
[0007] A metallurgical melt production of these material mixtures
or the corresponding sputter targets is difficult or impossible,
since the ceramic TiO.sub.x does not alloy with the cobalt-based
alloy. As a rule, mechanical stirring of TiO.sub.x particles into a
cobalt-based alloy melt does not result in a homogeneous material.
Powder metallurgical production methods are also problematic, since
there is, on the one hand, a mixing problem between metallic
particles and ceramic particles and, on the other hand, a technical
sputter problem because failures in the sputter process will result
if electrically insulating ceramic particles are present in sputter
targets. Surprisingly, these problems were also solved by the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The invention is explained by the following exemplary
embodiments.
Example 1
[0009] In a tumble mixer, 880 g of an inert gas atomized powder of
a cobalt chromium alloy having a chromium part of 12 weight % is
mixed for 24 hours with 120 g of a powder of pre-treated TiO.sub.x.
The mixture can also be prepared by other standard mixing methods,
for example with a ball mill or a drum mixer. The TiO.sub.x powder
is pretreated by vacuum annealing in a reducing atmosphere at a
temperature of approx. 1400.degree. C. The oxygen content in the
TiO.sub.x powder is reduced by the oxygen-reducing annealing by
approx. 2 weight % (versus the stoichiometric oxygen content).
Thereafter, the reduced TiO.sub.x powder is screened with a screen
of 50 .mu.m mesh size. In a tumble mixer the TiO.sub.x powder
having a particle size of less than 50 .mu.m is homogeneously
mixed, for 24 hours, with the powder of the cobalt chromium
alloy.
[0010] Thereafter, the resulting mixture of the cobalt chromium
alloy and 9 mol % TiO.sub.x is filled into a hot pressing form and
compressed in a vacuum press at 1100.degree. C. with a compacting
pressure of 30 MPa. The accordingly hot-pressed sputter target from
the described material mixture (CoCr12 TiO.sub.x) has a relative
density of 98.0% of the theoretical density. A metallographic
section preparation shows a very homogeneous distribution of the
electrically conductive TiO.sub.x particles in the cobalt alloy
matrix.
Example 2
[0011] A material mixture and sputter target having the composition
Co/Pt18 at %/Cr10 at %/TiO.sub.x8 mol % were produced analogously
to the method of Example 1.
[0012] It will be appreciated by those skilled in the art that
changes could be made to the embodiments described above without
departing from the broad inventive concept thereof. It is
understood, therefore, that this invention is not limited to the
particular embodiments disclosed, but it is intended to cover
modifications within the spirit and scope of the present invention
as defined by the appended claims.
* * * * *