U.S. patent application number 13/350638 was filed with the patent office on 2012-05-10 for methodology for recycling ru and ru-alloy deposition targets & targets made of recycled ru and ru-based alloy powders.
This patent application is currently assigned to HERAEUS INC.. Invention is credited to Carl Derrington, Patrick Griffin, William Heckman, Bernd Kunkel, Wuwen Yi.
Application Number | 20120111723 13/350638 |
Document ID | / |
Family ID | 40295624 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120111723 |
Kind Code |
A1 |
Yi; Wuwen ; et al. |
May 10, 2012 |
METHODOLOGY FOR RECYCLING RU AND RU-ALLOY DEPOSITION TARGETS &
TARGETS MADE OF RECYCLED RU AND RU-BASED ALLOY POWDERS
Abstract
A recycled deposition source is ruthenium (Ru) or Ru-based alloy
material in the form of a powder material having a size not greater
than a 325 mesh size and having an average tap density greater than
about 5 gm/cm.sup.3. The power material may be non-porous and not
agglomerated The recycled deposition source may have less than
about 500 ppm of iron and less than about 500 ppm of oxygen. The
recycled deposition source may be a recycled Ru or RuCr deposition
source, where the recycled Ru or RuCr deposition source has a
density comparable to a density of a Ru or RuCr deposition source
fabricated from virgin Ru or RuCr powder material, and has a
hardness greater than a hardness of a Ru or RuCr deposition source
fabricated from virgin Ru or RuCr powder material. The recycled
deposition source may be in the form of a sputtering target.
Inventors: |
Yi; Wuwen; (Tempe, AZ)
; Heckman; William; (Montague, MI) ; Kunkel;
Bernd; (Phoenix, AZ) ; Derrington; Carl;
(Tempe, AZ) ; Griffin; Patrick; (Chandler,
AZ) |
Assignee: |
HERAEUS INC.
Chandler
AZ
|
Family ID: |
40295624 |
Appl. No.: |
13/350638 |
Filed: |
January 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11927325 |
Oct 29, 2007 |
8118906 |
|
|
13350638 |
|
|
|
|
Current U.S.
Class: |
204/298.13 ;
420/462 |
Current CPC
Class: |
C22B 7/007 20130101;
C22B 11/02 20130101; Y02P 10/234 20151101; C23C 14/3414 20130101;
Y02P 10/20 20151101; C22B 7/005 20130101 |
Class at
Publication: |
204/298.13 ;
420/462 |
International
Class: |
C22C 5/04 20060101
C22C005/04; C23C 14/06 20060101 C23C014/06 |
Claims
1. A recycled deposition source comprising ruthenium (Ru) or
Ru-based alloy material in the form of a powder material having a
size not greater than a 325 mesh size and having an average tap
density greater than about 5 gm/cm.sup.3.
2. The recycled deposition source of claim 1, wherein the powder
material is non-porous, wherein the powder material is not
agglomerated, wherein the recycled deposition source comprises less
than about 500 ppm of iron (Fe) and less than about 500 ppm of
oxygen, wherein the recycled deposition source is a recycled Ru or
RuCr deposition source, wherein the recycled Ru or RuCr deposition
source has a density comparable to a density of a Ru or RuCr
deposition source fabricated from virgin Ru or RuCr powder
material, respectively, wherein the recycled Ru or RuCr deposition
source has a hardness greater than a hardness of a Ru or RuCr
deposition source fabricated from virgin Ru or RuCr powder
material, respectively.
3. The recycled deposition source of claim 1, wherein the powder
material is non-porous.
4. The recycled deposition source of claim 1, wherein the powder
material is not agglomerated.
5. The recycled deposition source of claim 1, wherein the recycled
deposition source comprises less than about 500 ppm of iron (Fe)
and less than about 500 ppm of oxygen.
6. The recycled deposition source of claim 1, wherein the recycled
deposition source is a recycled Ru deposition source, wherein the
recycled Ru deposition source has a density comparable to a density
of a Ru deposition source fabricated from virgin Ru powder
material, wherein the recycled Ru deposition source has a hardness
greater than a hardness of a Ru deposition source fabricated from
virgin Ru powder material.
7. The recycled deposition source of claim 1, wherein the recycled
deposition source is a recycled ruthenium-chromium (RuCr)
deposition source, wherein the recycled RuCr deposition source has
a density comparable to a density of a RuCr deposition source
fabricated from virgin RuCr powder material, wherein the recycled
RuCr deposition source has a hardness greater than a hardness of a
RuCr deposition source fabricated from virgin RuCr powder
material.
8. The recycled deposition source of claim 1, wherein the recycled
deposition source is in the form of a sputtering target.
9. The recycled deposition source of claim 2, wherein the recycled
deposition source is in the form of a sputtering target.
10. The recycled deposition source of claim 3, wherein the recycled
deposition source is in the form of a sputtering target.
11. The recycled deposition source of claim 4, wherein the recycled
deposition source is in the form of a sputtering target.
12. The recycled deposition source of claim 3, wherein the powder
material is not agglomerated.
13. The recycled deposition source of claim 3, wherein the powder
material is not agglomerated, wherein the recycled deposition
source comprises less than about 500 ppm of Fe and less than about
500 ppm of oxygen.
14. The recycled deposition source of claim 12, wherein the
recycled deposition source is a recycled Ru deposition source,
wherein the recycled Ru deposition source has a density comparable
to a density of a Ru deposition source fabricated from virgin Ru
powder material, wherein the recycled Ru deposition source has a
hardness greater than a hardness of a Ru deposition source
fabricated from virgin Ru powder material.
15. The recycled deposition source of claim 12, wherein the
recycled deposition source is a recycled ruthenium-chromium (RuCr)
deposition source, wherein the recycled RuCr deposition source has
a density comparable to a density of a RuCr deposition source
fabricated from virgin RuCr powder material, wherein the recycled
RuCr deposition source has a hardness greater than a hardness of a
RuCr deposition source fabricated from virgin RuCr powder
material.
16. The recycled deposition source of claim 13, wherein the
recycled deposition source is a recycled Ru deposition source,
wherein the recycled Ru deposition source has a density comparable
to a density of a Ru deposition source fabricated from virgin Ru
powder material, wherein the recycled Ru deposition source has a
hardness greater than a hardness of a Ru deposition source
fabricated from virgin Ru powder material.
17. The recycled deposition source of claim 13, wherein the
recycled deposition source is a recycled ruthenium-chromium (RuCr)
deposition source, wherein the recycled RuCr deposition source has
a density comparable to a density of a RuCr deposition source
fabricated from virgin RuCr powder material, wherein the recycled
RuCr deposition source has a hardness greater than a hardness of a
RuCr deposition source fabricated from virgin RuCr powder
material.
18. The recycled deposition source of claim 1, wherein the recycled
deposition source comprises less than about 500 ppm of oxygen,
wherein the recycled deposition source is formed using a method
comprising: providing a solid body of Ru or Ru-based alloy
material; segmenting the solid body to form a particulate material;
removing contaminants, including Fe, from the particulate material;
reducing particle sizes of the particulate material to form a
reduced powder material; removing contaminants, including Fe, from
the reduced powder material; reducing oxygen content of the reduced
powder material to form a purified powder material; and removing
particles greater than a predetermined size from the purified
powder material.
19. The recycled deposition source of claim 17, wherein the
recycled deposition source comprises less than about 500 ppm of Fe,
wherein the solid body is in the form of a spent deposition
source.
20. The recycled deposition source of claim 18, wherein the spent
deposition source comprises a sputtering target, and wherein the
Ru-based alloy material comprises Cr.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 11/927,325 entitled "Methodology For Recycling Ru and
Ru-Alloy Deposition Targets & Targets Made of Recycled Ru and
Ru-Based Alloy Powders," filed on Oct. 29, 2007, which is hereby
incorporated by reference in its entirety for all purposes.
FIELD
[0002] The present disclosure generally relates to methodology for
recycling ruthenium (Ru) and Ru-based alloy materials and to
products made from the recycled Ru and Ru-based alloy materials.
The disclosure has particular utility in recycling of Ru and
Ru-based alloy deposition targets, e.g., sputtering targets, and to
targets made from powders of the recycled Ru and Ru-based alloy
materials.
BACKGROUND
[0003] Ruthenium and ruthenium-based alloy materials are
increasingly utilized in the manufacture of a number of advanced
technology products, e.g., as coupling layers in high performance,
high areal recording density anti-ferromagnetically coupled ("AFC")
magnetic recording media and as adhesion/seed layers in
copper-based "back-end" metallization systems of high integration
density semiconductor integrated circuit ("IC") devices. Such
layers are typically formed by sputter deposition processing, e.g.,
magnetron sputtering, utilizing Ru or Ru-based alloy targets.
However, use of the sputtering targets in a given application is
limited due to consumption of the target over time, primarily
because of concern of target penetration due to irregular or uneven
(i.e., local) sputtering over the target surface. Economic
considerations arising from the high cost of Ru and Ru-based alloys
dictate recovery of these materials from spent targets.
[0004] Conventional methodology for recycling Ru and Ru-based alloy
materials, e.g., from spent targets, typically involves chemical
refining processing. However, such chemical refining processing
incurs a number of disadvantages, including: [0005] extremely long
processing intervals, e.g., on the order of about 12 weeks; [0006]
high cost; [0007] porous and highly agglomerated nature of the
recycled product, rendering it undesirable for use in subsequent
fabrication of new targets; and [0008] relatively low tap density
of the recycled product powder, i.e., about 4.0 gm/cc on average,
necessitating increase in the packing density prior to target
formation.
[0009] In view of the foregoing, there exists a clear need for
improved, more cost effective methodology for recycling Ru and
Ru-based alloy materials for facilitating re-use thereof, e.g., as
in the manufacture of Ru and Ru-based deposition targets (such as
sputtering targets) using recycled materials.
[0010] Further, there exists a clear need for improved,
cost-effective deposition targets comprising recycled Ru and
Ru-based alloy materials.
SUMMARY
[0011] In one aspect, an advantage of the present disclosure is an
improved method of recycling ruthenium (Ru) and Ru-based
alloys.
[0012] In one aspect, another advantage of the present disclosure
is an improved method of forming Ru and Ru-based alloy deposition
sources, e.g., sputtering targets, from spent sources.
[0013] In one aspect, yet another advantage of the present
disclosure is improved Ru and Ru-based alloy deposition sources,
e.g., sputtering targets, fabricated from Ru and Ru-based alloy
powders derived from spent deposition sources.
[0014] Additional advantages and features of the present disclosure
will be set forth in the disclosure which follows and in part will
become apparent to those having ordinary skill in the art upon
examination of the following or may be learned from the practice of
the present disclosure. The advantages may be realized and obtained
as particularly pointed out in the appended claims.
[0015] According to an aspect of the present disclosure, the
foregoing and other advantages are achieved in part by an improved
method of recycling ruthenium (Ru) and Ru-based alloys, comprising
steps of: [0016] (a) providing a solid body of Ru or a Ru-based
alloy; [0017] (b) segmenting the solid body to form a particulate
material; [0018] (c) removing contaminants, including iron (Fe),
from the particulate material; [0019] (d) reducing the particle
sizes of the particulate material to form a powder material; [0020]
(e) removing contaminants, including Fe, from the powder material;
[0021] (f) reducing oxygen content of the powder material to below
a predetermined level to form a purified powder material; and
[0022] (g) removing particles greater than a predetermined size
from the purified powder material.
[0023] According to embodiments of the present disclosure, step (a)
comprises providing a solid body in the form of a spent deposition
source, e.g., a sputtering target, and the method further comprises
a step of: [0024] (h) forming a deposition source, e.g., a
sputtering target, from the purified powder material.
[0025] Embodiments of the present disclosure include those wherein
step (h) comprises consolidating the purified powder to have a tap
density >.about.5 gm/cm.sup.3; and step (h) comprises hot
isostatic pressing ("HIP"), vacuum hot pressing, or spark plasma
sintering, and optionally further comprises cold isostatic pressing
("CIP").
[0026] Further embodiments of the present disclosure include those
wherein step (h) comprises addition of a predetermined amount of at
least one element to the purified powder prior to consolidating,
e.g., as when step (a) comprises providing a solid body of a RuCr
alloy; and step (h) comprises adding a predetermined amount of
chromium (Cr) to the purified powder.
[0027] According to embodiments of the present disclosure, step (b)
comprises optional jaw crushing followed by hammer milling; step
(c) comprises a first leaching to remove iron (Fe) and other
contaminants, followed by drying; step (d) comprises impact
milling; step (e) comprises a second leaching to reduce Fe content
to <.about.500 ppm and remove other contaminants, followed by
drying, and further comprises performing a magnetic separation to
remove Fe prior to the second leaching; step (f) comprises reducing
oxygen content to <.about.500 ppm, as by performing a reduction
process in an atmosphere containing hydrogen gas and annealing the
purified powder material during the reduction process.
[0028] In one aspect, preferably, step (e) comprises reducing Fe
content to <.about.500 ppm; and step (f) comprises reducing
oxygen content <.about.500 ppm.
[0029] Another aspect of the present disclosure is recycled Ru or
Ru-based alloys made by the above process, e.g., powder materials
having a desired mesh size, e.g., 325 mesh, and tap density
>.about.5 gm/cm.sup.3.
[0030] Still another aspect of the subject technology is Ru and Ru
alloy-based deposition sources, e.g., Ru and RuCr sputtering
targets, fabricated from the powder material formed by the above
process, with densities comparable to those of Ru and Ru-based
sources/targets fabricated from virgin Ru and RuCr powder material
and hardness greater than those of Ru and Ru-based sources/targets
fabricated from virgin Ru and RuCr powder material.
[0031] Additional advantages and aspects of the present disclosure
will become readily apparent to those skilled in the art from the
following detailed description, wherein only the preferred
embodiments of the present disclosure are shown and described,
simply by way of illustration of the best mode contemplated for
practicing the present disclosure. As will be realized, the
disclosure is capable of other and different embodiments, and its
several details are capable of modification in various obvious
respects, all without departing from the spirit of the present
disclosure. Accordingly, the drawing and description are to be
regarded as illustrative in nature, and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWING
[0032] The following detailed description of the embodiments of the
present disclosure can best be understood when read in conjunction
with the following drawing, in which:
[0033] FIG. 1 is a flow chart schematically showing an
illustrative, but non-limitative embodiment according to the
present disclosure.
DETAILED DESCRIPTION
[0034] In one aspect, the subject technology addresses and
effectively solves, or at least mitigates, several problems and/or
disadvantages associated with conventional chemical-based
methodology for recycling products/apparatus containing Ru and
Ru-based alloy materials, e.g., thin film deposition sources such
as sputtering targets, and is based upon discovery that
recovery/recycling of Ru and Ru-based alloy materials can be formed
in an efficient, cost-effective manner which substantially reduces
the processing interval.
[0035] More specifically, in one aspect, the presently disclosed
methodology overcomes the following disadvantages associated with
conventional chemical refining processing for Ru
recovery/recycling, including the high cost; extremely long
processing intervals, e.g., on the order of about 12 weeks; the
porous and highly agglomerated nature of the recycled product,
rendering it undesirable for use in subsequent fabrication of new
deposition sources, such as sputtering targets; and the relatively
low tap density of the recycled product powder, i.e., about 4.0
gm/cm.sup.3 on average, necessitating increase in the packing
density prior to target formation.
[0036] The improved methodology for Ru recovery/recycling will now
be described in detail with reference to FIG. 1, which is a flow
chart schematically showing an illustrative, but non-limitative,
embodiment according to the present disclosure wherein spent
sputtering targets are subjected to a recycling process for
recovering high purity Ru and Ru-based alloy materials for re-use
in the manufacture of new sputtering targets.
[0037] In a first step according to the process methodology, a
solid body of Ru or Ru-based alloy material, i.e., a spent
sputtering target is provided and mechanically segmented into
appropriately sized particles, illustratively 1 mm (.about.0.04 in)
pieces. Mechanical segmentation may, if desired, be accomplished
via a 2-stage process comprising an initial jaw crushing step to
form pieces in the 30-50 mm (.about.1-2 in.) size range, followed
by hammer milling to form smaller pieces in the 1 mm (.about.0.04
in) size range.
[0038] According to the next step of the process methodology, the
smaller pieces are subjected to a first leaching, e.g., with a
strong mineral acid such as hydrochloric (HCl) or nitric
(HNO.sub.3) acid, at room temperature for from about 12 to about 48
hrs., in order to remove contaminants from the pieces, especially
any iron (Fe) introduced during the segmentation process. The
leached particles are then subjected to a first oven drying, and
impact milled to form a powder material with about 325 mesh
size.
[0039] The powder material is then subjected to a second leaching,
e.g., with a strong mineral acid such as hydrochloric (HCl) or
nitric (HNO.sub.3) acid, at room temperature for from about 12 to
about 48 hrs., to further remove contaminants, followed by a second
oven drying. The Fe content of the dried powder after the second
leaching should be very low, i.e., <500 ppm, in order to
prevent, or at least limit, diffusion of any Fe present on the
surfaces of the powder particles into the interior thereof during
subsequent processing, e.g., hydrogen reduction. In this regard, it
should be recognized that any Fe present in the interior of the
powder particles is difficult to remove, e.g., by leaching.
[0040] According to the next step of the instant process
methodology, the dried powder from the second leaching step is
subjected to reduction in a hydrogen (H.sub.2) gas atmosphere at
about 1,000.degree. C. for about 12 hrs., to reduce oxygen content
of the powder to below a desired level, typically <500 ppm. An
advantageous feature of the present methodology annealing of the
powder during the hydrogen reduction process, whereby any work
hardening of the material incurred during the earlier segmentation
processing is reduced. The feature of annealing during hydrogen
reduction is critical for facilitating subsequent consolidation of
the recycled powder.
[0041] The resultant purified powder is then sieved through a mesh
screen, e.g., 325 mesh, to remove oversize particles and yield
purified recycled Ru or Ru-based alloy powder material.
[0042] The purified recycled Ru or Ru-based alloy material can be
utilized, inter alia, for making Ru and Ru-based alloy deposition
sources, e.g., sputtering targets. In the case of recycled RuCr
powder, Cr may be added thereto according to the desired final
composition of the deposition source.
[0043] According to methodology afforded by the instant disclosure,
the recycled purified Ru or Ru-based alloy powder is subjected to
consolidation processing, which may include optional CIP followed
by HIP, vacuum hot pressing, or spark plasma sintering to achieve
full density. In this regard, whereas CIP is required for
chemically recycled Ru or Ru-based alloy powder because of its low
tap density (<5 gm/cm.sup.3), CIP of recycled Ru or Ru-based
alloy powder formed according to the present methodology is not
necessarily required in view of its higher tap density (>5
gm/cm.sup.3).
[0044] Ru and Ru alloy-based deposition sources, e.g., Ru and RuCr
sputtering targets, fabricated from the powder material formed by
the above process by conventional powder metallurgical techniques,
have densities comparable to those of Ru and Ru-based
sources/targets fabricated from virgin Ru and RuCr powder material
and hardness greater than those of Ru and Ru-based sources/targets
fabricated from virgin Ru and RuCr powder material.
[0045] Recycled Ru and Ru-based alloys, and products fabricated
therefrom, such as deposition sources (e.g., sputtering targets),
have reduced Fe content of <.about.500 ppm and reduced oxygen
content <.about.500 ppm.
[0046] In one aspect, advantages afforded by the present
methodology include: [0047] 1. the total recycling time is about 2
weeks, which is only about 17% of the recycling time required by
the conventional chemical recycling process (i.e., about 12 weeks);
[0048] 2. recycling cost is significantly less expensive than that
of the conventional chemical recycling process; [0049] 3. the
recycled powder is non-porous and not agglomerated, whereas the
recycled powder produced by the conventional chemical recycling
process is porous and highly agglomerated. In this regard,
agglomerated powder is not preferred for use in deposition source
(e.g., sputtering target) manufacture via powder metallurgical
techniques; and [0050] 4. The recycled powder produced by the
present process has a high average tap density >.about.5
gm/cm.sup.3 (as compared with an average tap density of only about
4 gm/cm.sup.3 with powder produced via conventional chemical
recycling), thereby facilitating formation of deposition sources
via powder metallurgical techniques not requiring a CIP step to
increase tap density. As a consequence, the present methodology
affords further cost and processing time reductions.
[0051] In the previous description, numerous specific details are
set forth, such as specific materials, structures, processes, etc.,
in order to provide a better understanding of the subject
technology. However, the subject technology can be practiced
without resorting to the details specifically set forth herein. In
other instances, well-known processing techniques and structures
have not been described in order not to unnecessarily obscure the
subject technology.
[0052] Examples of embodiments of the subject technology with
various versatility are shown and described in the present
disclosure. It is to be understood that the subject technology is
capable of use in various other combinations and environments and
is susceptible of changes and/or modifications within the scope of
the inventive concept as expressed herein.
* * * * *