JP2011516369A - Method for recycling and purification of inorganic metal precursors - Google Patents

Abstract

  Method and apparatus for recycling and purification of inorganic metal precursors. A first gas stream comprising ruthenium tetroxide is provided and converted to solid phase lower ruthenium oxide. This lower ruthenium oxide is reduced with hydrogen to produce metal ruthenium. The metal ruthenium comes into contact with the oxidizing mixture, resulting in a stream containing ruthenium tetroxide, and any remaining oxidizing mixture is removed from this stream by distillation.

Description

This application claims the benefit of US Provisional Patent Application No. 60 / 910,572, filed Apr. 6, 2007, which is hereby incorporated by reference in its entirety for all purposes.

BACKGROUND Field of the Invention This invention relates generally to the field of semiconductor manufacturing. More specifically, the present invention relates to a method for recycling a waste stream containing ruthenium tetroxide from a semiconductor manufacturing process.

BACKGROUND OF THE INVENTION Ruthenium compounds such as ruthenium and ruthenium tetroxide are considered promising for use as capacitor electrode materials in next generation DRAMs. High dielectric constant materials (also known as high-k materials) such as alumina, tantalum pentoxide, hafnium oxide, and barium-strontium titanate (BST) are currently used for these capacitor electrodes. However, these high-k materials are manufactured using temperatures as high as 600 ° C., which results in oxidation of polysilicon, silicon, and alumina and results in loss of capacitance. On the other hand, both ruthenium and ruthenium oxide exhibit high oxidation resistance and high conductivity, and are suitable for use as capacitor electrode materials. They also function effectively as oxygen diffusion barriers. Ruthenium has also been proposed as a gate metal for lanthanoid oxides. Furthermore, ruthenium is more easily etched by plasma using ozone and oxygen than platinum and other noble metals. The use of ruthenium as a barrier layer that separates the low-k material from the plated copper and as a seed layer has also gained attention in recent years.

High quality films of ruthenium and ruthenium oxide (RuO ₂ ) can be deposited from precursors of high purity ruthenium tetroxide (RuO ₄ ) under suitable conditions. This precursor is used for the deposition (film formation) of perovskite-type materials such as strontium ruthenium oxide, which exhibits excellent conductivity and three-dimensional structure similar to those of barium-strontium titanate and strontium titanium oxide. Can also be used for.

  When ruthenium tetroxide is used as a precursor in a semiconductor manufacturing process, it may be necessary to capture and / or remove any ruthenium tetroxide left in or exhausted from the process. One method for capturing ruthenium tetroxide uses rubber (either natural, chloroprene or silicon type) to recover ruthenium tetroxide at room temperature. When ruthenium tetroxide comes into contact with an organic type material, the ruthenium tetroxide is converted to ruthenium dioxide, which cannot then be used again. It may be possible to capture the remaining ruthenium with a silica-alumina gel, but this also introduces some difficulties in releasing the ruthenium for subsequent reuse.

  There are also several methods for purifying ruthenium, but these require additional processing chemicals (sodium) that must be subsequently processed and can create health, safety and environmental concerns. , Hydrochloric acid, hydrogen, or other inorganic acids) is generally required.

  Accordingly, there is a need for a method and apparatus for recycling and purifying ruthenium tetroxide that does not produce many harmful by-products that are used in semiconductor manufacturing processes and then must be disposed of.

SUMMARY The present invention provides a novel method and apparatus for recycling and purifying inorganic metal precursors, namely ruthenium tetroxide.

  In one embodiment, a method for recycling and purifying inorganic metal precursors includes providing a first gas stream comprising ruthenium tetroxide. At least a portion of the first stream is converted to solid phase lower ruthenium oxide. The metal ruthenium is then made by converting at least a portion of the lower ruthenium oxide to metal ruthenium by reducing the lower ruthenium oxide with hydrogen gas. The metal ruthenium is then contacted with the oxidizing mixture to produce a second stream containing ruthenium tetroxide. This second stream removes any remaining oxidizing compounds to obtain high purity ruthenium tetroxide.

  In one embodiment, a method for recycling and purifying inorganic metal precursors received from a semiconductor process tool includes receiving a first gas stream containing ruthenium tetroxide from the output of a semiconductor manufacturing process. At least a portion of the first stream is converted to solid phase lower ruthenium oxide by heating the first stream in a heated vessel maintained at a temperature of about 50 to about 300 ° C. The metal ruthenium is then made by converting at least a portion of the lower ruthenium oxide to metal ruthenium by reducing the lower ruthenium oxide with hydrogen gas. The metal ruthenium is then contacted with the oxidizing mixture to produce a second stream containing ruthenium tetroxide. The second stream is stripped of any remaining oxidizing compounds to obtain high purity ruthenium tetroxide with a purity of approximately 99.9%. High purity ruthenium tetroxide is then provided to semiconductor process tools for use in deposition processes.

  In one embodiment, an apparatus for recycling and refining inorganic metal precursors used in the manufacture of semiconductor devices includes an inlet for receiving an inflow containing at least one inorganic metal precursor. At least one heating vessel suitable for receiving the stream is provided, the heating vessel including suitable heating means to maintain the vessel at a temperature of approximately 50-300 ° C. At least one condenser is provided that is in fluid communication with the heating vessel and disposed downstream of the heating vessel. There is also provided at least one distribution means in fluid communication with the condenser and disposed downstream of the condenser. An outlet is provided in fluid communication with the distribution means, wherein the outlet is suitable for delivering a stream of inorganic metal precursor to at least one semiconductor process tool.

Other aspects of the invention may include, but are not limited to, one or more of the following features:
-Converting at least part of the first stream by introducing the first stream into a heating vessel;
-Maintaining the operating temperature of the heating vessel at approximately 50 to 800 ° C;
-Maintain the operating pressure of the heating vessel at about 0.01 to about 1000 torr;
-Providing a catalyst to the heating vessel to help convert at least a portion of the ruthenium tetroxide to solid phase lower ruthenium oxide;
-The catalyst contains metal ruthenium or ruthenium dioxide;
-Maintain the operating temperature of the heating vessel at approximately 100-300 ° C;
-Reducing at least 99%, preferably approximately 99.9% of the ruthenium oxide to metallic ruthenium by reduction with hydrogen gas;
-The metal ruthenium produced by reduction with hydrogen has a specific surface area of more than approximately 1.0 m ² / g, preferably approximately 7.0 m ² / g;
-Removing at least a portion of the metal ruthenium from the heating vessel after the reduction of the ruthenium oxide with hydrogen and before the metal ruthenium contacts the oxidizing mixture;
- oxidizing _{mixtures, NO, NO 2, O 2} , O 3, mixtures thereof, and comprise at least one element plasma excited selected from the group consisting of halogen;
-Removing any oxidizing compounds from the second stream of ruthenium tetroxide by a distillation process;
-Obtaining ruthenium tetroxide with a purity of more than approximately 99.9%;
-Bubbling high purity ruthenium tetroxide into the solvent to form a saturated mixture of the solvent and high purity ruthenium tetroxide;
-Vaporizing ruthenium tetroxide directly by a vaporization process;
-Making high purity ruthenium tetroxide without introducing sodium or halogen containing compounds;
-Providing a hydrogen source arranged to be in fluid communication with the heating vessel;
-Providing an oxidizing mixture source arranged in fluid communication with the heating vessel;
-A second heating vessel, condenser and distribution means are provided which are all arranged parallel to the first container, condenser and distribution means;
-Means are provided between the first heating vessel and the second heating vessel to divert the incoming stream of inorganic metal precursor;
-Providing a catalyst that is deposited inside the heated vessel so that the stream of inorganic metal precursor is in contact with the catalyst;
-Providing high purity ruthenium tetroxide to semiconductor process tools that temporarily receive the first gas stream.

  The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description that follows may be better understood. Additional features of the invention are described below and form the subject of the invention. It should be understood by one skilled in the art that the disclosed concepts and specific aspects can be readily utilized as a basis for modifying or designing other configurations for carrying out the same purposes of the present invention. It should also be understood by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

  For a further understanding of the nature and objects of the invention, reference will be made to the following detailed description taken in conjunction with the accompanying drawings, in which like elements are provided with like or identical reference numerals.

DESCRIPTION OF PREFERRED EMBODIMENTS In general, it is preferable from both an environmental and cost standpoint that materials used in the manufacture of semiconductor devices can be captured and reused instead of discarded. When ruthenium is used in the manufacture of these devices, the process usually requires that ruthenium be supplied in the form of ruthenium tetroxide. Since these processes do not use all of the ruthenium tetroxide, ruthenium tetroxide can be present in the process waste (along with other byproducts). Preferably, ruthenium tetroxide can be captured and purified so that it can be reused in the same or different manufacturing processes.

  In general, the present invention relates to a method for recycling and purifying inorganic metal precursors, including providing a first gas stream comprising ruthenium tetroxide. At least a portion of the first stream is converted to solid phase lower ruthenium oxide. The metal ruthenium is then made by converting at least a portion of the lower ruthenium oxide to metal ruthenium by reducing the lower ruthenium oxide with hydrogen gas. The metal ruthenium is then contacted with the oxidizing mixture to produce a second stream containing ruthenium tetroxide. This second stream is stripped of any remaining oxidizing compounds to obtain high purity ruthenium tetroxide. The invention also relates to an apparatus for recycling and purifying inorganic metal precursors used in the manufacture of semiconductor devices comprising an inlet for receiving an inflow containing at least one inorganic metal precursor. At least one heating vessel suitable for receiving the stream is provided, the heating vessel including suitable heating means to maintain the vessel at a temperature of approximately 50-300 ° C. At least one condenser is provided that is in fluid communication with the heating vessel and disposed downstream of the heating vessel. There is also provided at least one distribution means in fluid communication with the condenser and disposed downstream of the condenser. An outlet is provided in fluid communication with the distribution means, wherein the outlet is suitable for delivering a stream of inorganic metal precursor to at least one semiconductor process tool.

Referring now to FIG. 1, a non-limiting embodiment of the method and apparatus according to the present invention will now be described. A precursor recycling and purification system 100 is shown. A first stream of inorganic metal precursor 101 containing ruthenium tetroxide is provided. This stream may be waste or excess product from semiconductor deposition processes such as chemical vapor deposition (CVD) or atomic layer deposition (ALD) processes. The first stream 101 can be sent to a heated vessel 102 having an inlet, an outlet, and at least one inner surface 103 suitable for collecting solid precursor therein. The heating vessel 102 may also include heating means 104 suitable for maintaining the temperature of the heating vessel 102 at a temperature of approximately 50 to 800 ° C, preferably approximately 100 to 300 ° C.
In some embodiments, the heating vessel 102 can be a conventional type of metal reaction vessel known to those skilled in the art. The heating vessel 102 can be constructed to be suitable for maintaining the internal pressure at about 0.01 torr to about 1000 torr. Similarly, in some embodiments, the heating means 104 can be a conventional heating means such as a resistance heater or a direct heater that provides heat to the walls of the heating vessel.

In some embodiments, the heating means 102 is in fluid communication with the hydrogen source 105 and the oxidant mixture source 106. Both the hydrogen source 105 and the oxidant mixture 106 can be conventional sources such as gas cylinders, or can be connected to the outlets of other supply lines or supply systems. In some embodiments, the oxidizable mixture 106 can be NO, NO ₂ , O ₂ , O ₃ , or a mixture thereof.

When the first stream 101 enters the heating vessel 102, the ruthenium tetroxide contained in the first stream 101 is decomposed by heating in accordance with a normal decomposition reaction generally as shown below to produce a solid lower ruthenium oxide. Yields (e.g. ruthenium dioxide);

  In some embodiments, the amount of heat required for this reaction can be approximately 100-300 ° C, preferably approximately 210 ° C. Any by-products of the decomposition reaction other than lower ruthenium (eg, oxygen) can be sent out of the heating vessel 102 and sent to the vent 108. The produced lower ruthenium can form the inner surface 103 of the heating vessel 102.

  In some embodiments, a catalyst may be added to the heated vessel 102 to assist in the conversion of ruthenium tetroxide to lower ruthenium oxide. The catalyst can be mechanically added to at least one internal surface 103 of the heating vessel 102 through conventional methods, such as through an access panel (not shown) in the heating vessel 102. In some embodiments, the catalyst can be metal ruthenium or ruthenium dioxide.

This lower ruthenium located on the inner surface 103 of the heating vessel can then be converted to metallic ruthenium by introducing hydrogen gas 105 into the heating vessel 102. Hydrogen gas 105 introduced in an amount below the lower explosion limit (e.g., 4% by volume) generally reduces ruthenium oxide to metallic ruthenium by a normal reduction reaction as shown below;

  Since no compounds other than hydrogen are used, the yield of this reduction reaction is very high and can be greater than about 99%, preferably greater than about 99.9%. Some reaction products other than the metal ruthenium (eg, hydrogen, oxygen, or water vapor) can be sent out of the heating vessel 102 and sent to the vent 108.

The metal ruthenium produced by this method has proven to have at least one advantageous property in that it has a large specific surface area. For example, the specific surface area of metallic ruthenium made according to some embodiments of the present invention is greater than approximately 1.0 m ² / g, preferably approximately 7.0 m ² / g.

In some embodiments, at least a portion of the metal ruthenium can be removed from the heating vessel 102 after reduction of the ruthenium oxide with hydrogen and prior to contacting the metal ruthenium with the oxidant mixture. The removal of the metal ruthenium can be done by conventional methods, for example by mechanically removing a portion of the metal from the heating vessel 102 via an access panel (not shown). The metal ruthenium can then be used in various other processes, for example in the synthesis of other precursors (eg RuCl ₃ ).

After the metal ruthenium is made, the metal ruthenium contacts the oxidant mixture 106 to produce ruthenium tetroxide. In one embodiment where the oxidizing mixture is ozone, the formation of ruthenium tetroxide generally occurs as shown below;

  In these embodiments, the oxidant mixture 106 is flowed through the metal ruthenium and the metal ruthenium is corroded in the gas stream. The amount of ruthenium tetroxide contained in the gas stream can be measured by monitoring with an analyzer 109 located downstream of the heating vessel 102. The analyzer 109 can be a conventional type of analyzer known to those skilled in the art, for example, the analyzer 109 can be a UV spectrometer.

  Ruthenium tetroxide made according to at least one embodiment of the present invention has proven to have at least one advantageous property in that the production rate of ruthenium tetroxide is very fast. Due to the high yield of metal ruthenium, there is little or no ruthenium oxide layer on the metal ruthenium that can interfere with the reaction of the oxidant mixture and metal ruthenium in the formation of ruthenium tetroxide. . This results in the rapid and efficient production of ruthenium tetroxide from the metal ruthenium.

  After the ruthenium tetroxide incorporated into the gas stream is made, the ruthenium tetroxide is then removed of any remaining oxidizing compounds to make high purity ruthenium tetroxide. In some embodiments, high purity ruthenium tetroxide is made by separating oxidizable compounds by a cryogenic distillation type process. For example, ruthenium tetroxide is collected by condensation of ruthenium tetroxide, while oxidizing compounds having a low boiling point (e.g., ozone or oxygen) do not pass through cryogenic distillation column 110 and are sent to vent 108. It can be separated from the oxidant mixture by sending the mixture to a cryogenic distillation column 110 at temperature. In some embodiments, the process provides purified ruthenium tetroxide with a purity of approximately 99.9% or greater.

  After the ruthenium tetroxide has been separated from the oxidizing compound, the ruthenium tetroxide can be sent to a distribution means 111 that provides the ruthenium tetroxide for distribution to the semiconductor manufacturing process 112. In some embodiments, the purified ruthenium tetroxide is a semiconductor manufacturing process (e.g., CVD or ALD deposition) such that the dispensing means 111 can be a flow controller that regulates the amount of ruthenium tetroxide dispensed to the process 112. Can be used directly. In some embodiments, the purified ruthenium tetroxide can first be bubbled through a solvent before being provided to the manufacturing process 112. In these embodiments, the purified ruthenium tetroxide can be sent from the distillation column 110 to the distribution means 111 where the solvent (e.g., HFE--all commercially available from 3M Company) before being provided to the manufacturing process. 7500, HFE 7100, HFE, 7200 or mixtures thereof). The dispensing means 111 can be a conventional type of bubbler known to those skilled in the art. In some embodiments, the dispensing means 111 can be a direct vaporization type system where ruthenium tetroxide can be introduced into the manufacturing process 112 via a direct vaporization step. Such direct vaporization systems are known in the art and may include liquid mass flow controllers or vaporizers such as glass or metal tubes. Inert gas (eg, nitrogen, argon, helium, etc.) can be used to pressurize ruthenium tetroxide and flow ruthenium tetroxide from the storage vessel through the liquid flow controller to the vaporizer. If inert gas is not used to flow the liquid, a vacuum (or low pressure condition) can be generated downstream of the precursor storage vessel, eg, at the vaporizer outlet.

  With respect to the previously described aspects of the invention, it is known that various other elements such as valves and flow controllers can be incorporated into the system as needed. For example, all the elements previously mentioned (eg heating vessel 102, distillation column 110, distribution means 111) can have valves arranged upstream or downstream, as known to those skilled in the art. Similarly, various flow controllers can be incorporated to control and change the flow rates of various gases used in accordance with aspects of the present invention. For convenience, these elements are not shown in FIG. 1, but are understood to be incorporated into various aspects of the invention.

  With reference to FIG. 2, a non-limiting embodiment of the device according to the invention is described below. In this embodiment, the apparatus described in FIG. 1 is generally provided (the same numbers indicate similar elements). A second set of elements (e.g., a second heating vessel 202, a second analyzer 209, a second distillation column 210 and a second distribution means 211) is provided in the first heating vessel 102, the first analysis. Provided in a parallel arrangement with respect to the vessel, the first distillation column 110 and the first distribution means 111 (eg a first set of elements). Furthermore, means 203 for diverting the inflow of the inorganic metal precursor is provided between the first heating container 102 and the second heating container 202. In some embodiments, the diverter means 203 can be a conventional type of three-way valve. In this embodiment, the parallel arrangement allows for the delivery of ruthenium tetroxide from one set of elements, while the other set of elements either recycles or purifies ruthenium tetroxide, Purified ruthenium tetroxide can be continuously provided to the semiconductor tool (eg, manufacturing process) 112. That is, the parallel arrangement allows receipt of the first gas stream 101 at the same time as the delivery of purified ruthenium tetroxide to the semiconductor tool (eg, manufacturing process) 112.

  While the foregoing describes the present invention with respect to methods and apparatus for recycling and purification of inorganic metal precursors (eg, ruthenium tetroxide), the present invention can also be applied to precursor compounds containing osmium.

Examples The following non-limiting examples are given to further illustrate aspects of the present invention. However, all examples are not intended to be exhaustive and are not intended to limit the scope of the invention described herein.

Example 1
Commercial ruthenium (200 micron mesh ruthenium powder obtained from Sigma-Aldrich) and ruthenium recycled according to embodiments of the present invention were compared. Prior to analysis, both samples were dried in an N2 / He atmosphere at 120 ° C. for 2 hours and the specific surface area of each was examined by BET analysis. Recycled ruthenium showed a specific surface area that was 18 times greater than the commercial one.

Example 2
The efficiency of hydrogen reduction was investigated by the difference in ozone cleaning capacity on two sputtered ruthenium samples, one of which was reduced with hydrogen (`` treated ''). The other was not reduced ("untreated"). Two ruthenium samples of approximately 1000 A were deposited on the chromium layer (adhesion layer). The sample to be treated was first treated by a reduction reaction with hydrogen (4% hydrogen in nitrogen) at a temperature of approximately 200 ° C. under atmospheric pressure. This treatment lasted approximately 5 minutes. Such treatment was not performed on the untreated sample. Both samples were then exposed to a stream of ozone (5% ozone / oxygen). An Auger depth direction analysis was then performed on both samples. FIG. 3 shows the results from the treated sample, while FIG. 4 shows the results for the untreated sample. FIG. 5 shows the response time for the sample to be processed in the production of ruthenium tetroxide after the flow of the oxidizing (ozone) mixture has begun.

Example 3
Tests to separate ruthenium tetroxide from the residual oxidizing compounds produced according to embodiments of the present invention were conducted using a distillation column / cold trap. A cold trap with the temperature set at −30 ° C. was provided and a ruthenium tetroxide / ozone mixture was flowed through the trap. In this example, propanol was mixed with liquid nitrogen to provide a low temperature. When the mixture was flushed through a trap (in this case glass), a characteristic yellow color change could be observed when ruthenium tetroxide was collected. Since the boiling points of ozone and oxygen are low (−112 ° C. and −183 ° C., respectively), none of these molecules are trapped in the cooling device, thus ensuring a high degree of purification of ruthenium tetroxide. The delivery of ruthenium tetroxide was then examined by a UV spectrometer, and the production of ruthenium tetroxide was monitored as a function of temperature. FIG. 6 shows how the delivered ruthenium tetroxide stream is controlled by accurately setting the appropriate temperature in the distillation column / cold trap.

  While embodiments of the invention have been illustrated and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The described embodiments and examples provided herein are merely exemplary and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible within the scope of the invention. Accordingly, the scope of protection is not limited to the description presented above, but is limited only by the following claims, the scope of which includes all equivalents of the subject matter of the claims.

FIG. 1 is a schematic diagram of one embodiment of a process for recycling and purifying inorganic metal precursors. FIG. 2 is a schematic diagram of another embodiment of a process for recycling and purifying inorganic metal precursors. FIG. 3 shows the experimental results according to one embodiment of the present invention. FIG. 4 shows the results of a comparative experiment relative to that shown in FIG. FIG. 5 shows the experimental results according to one embodiment of the present invention. FIG. 6 shows the experimental results according to one embodiment of the present invention.

Claims (22)

A method for recycling and purifying inorganic metal precursors, comprising:
a) providing a first gas stream comprising ruthenium tetroxide;
b) converting at least a portion of the first stream of ruthenium tetroxide to a solid lower ruthenium oxide;
c) making metal ruthenium by converting at least a portion of the ruthenium oxide to metal ruthenium by reducing the ruthenium oxide with hydrogen;
d) contacting the metal ruthenium with an oxidizing mixture to create a second stream comprising ruthenium tetroxide; and
e) A method comprising removing any oxidizing compounds from said second stream of ruthenium tetroxide to obtain high purity ruthenium tetroxide. a) converting at least a portion of the first stream by introducing the first stream into a heating vessel;
b) maintaining the operating temperature of the heating vessel at approximately 50 to 800 ° C .;
The method of claim 1, further comprising: c) maintaining the operating pressure of the heated vessel at about 0.01 to about 1000 torr.   The method of claim 2, further comprising providing a catalyst in the heated vessel to help convert at least a portion of the ruthenium tetroxide to the solid phase lower ruthenium oxide.   The process of claim 3 wherein the catalyst comprises ruthenium metal or ruthenium dioxide.   The method of claim 2, further comprising maintaining an operating temperature of the heating vessel at approximately 100-300 ° C.   The method of claim 1, wherein at least about 99% of the ruthenium oxide is reduced to metallic ruthenium by reduction with hydrogen.   The method of claim 6, wherein at least about 99.9% of the ruthenium oxide is reduced to metal ruthenium by a reduction reaction with hydrogen. The method of claim 1, wherein the ruthenium metal produced by reduction with hydrogen has a specific surface area greater than about 1.0 m ² / g. The method of claim 1, wherein the metal ruthenium produced by reduction with hydrogen has a specific surface area of greater than about 7.0 m ² / g.   The method of claim 1, further comprising removing at least a portion of the metal ruthenium from the heating vessel after reduction of the ruthenium oxide with hydrogen and before the metal ruthenium and the oxidizing mixture contact. The oxidizing mixture is
a) NO,
b) NO ₂ ,
c) O ₂ ,
d) O ₃ ,
e) the mixture, and
f) The method of claim 1 comprising at least one element selected from the group consisting of the plasma excited species. a) removing any oxidizing compounds from the second stream of ruthenium tetroxide by a distillation process; and
2. The method of claim 1 comprising obtaining ruthenium tetroxide having a purity of approximately greater than 99.9%.   The method of claim 1, further comprising bubbling the high purity ruthenium tetroxide through a solvent to form a saturated mixture of the solvent and high purity ruthenium tetroxide.   The method of claim 1, further comprising vaporizing the ruthenium tetroxide by a direct vaporization step.   The method of claim 1, further comprising, in any of steps (a) to (e), making the high purity ruthenium tetroxide without introducing a compound containing sodium or halogen. An apparatus for recycling and purification of a stream of inorganic metal precursors used in the manufacture of semiconductor devices,
a) an inlet for receiving an inflow of inorganic metal precursor;
b) At least one first heating vessel suitable for receiving the stream of the inorganic metal precursor, the heating vessel comprising heating means suitable for heating the vessel to a temperature of approximately 50 to 300 ° C. When,
c) at least one condenser in fluid communication with the heating vessel and disposed downstream of the heating vessel;
d) at least one distribution means in fluid communication with the condenser and disposed downstream of the condenser;
e) an apparatus comprising an outlet in fluid communication with the distribution means for sending a stream of inorganic metal precursor to at least one semiconductor process tool. a) a hydrogen source arranged in fluid communication with the heating vessel;
The apparatus of claim 16, further comprising: b) an oxidizing mixture source positioned in fluid communication with the heating vessel. a) a second heating vessel, a condenser and a distribution means, all arranged parallel to the first container, the condenser and the distribution means;
The apparatus of claim 16, further comprising: b) means for diverting an inflow of inorganic metal precursor between the first and second vessels.   The apparatus of claim 16, further comprising a catalyst deposited inside the heated vessel such that the stream of inorganic metal precursor is in contact with the catalyst.   The apparatus of claim 16, wherein the stream of inorganic precursors sent to the semiconductor process tool comprises at least approximately 99.9% ruthenium tetroxide. A method for recycling and purifying inorganic metal precursors received from a semiconductor process tool, comprising:
a) receiving a first gas stream comprising ruthenium tetroxide from the exit of the semiconductor process tool;
b) heating at least a portion of the first stream of ruthenium tetroxide to a solid lower ruthenium oxide by heating the first stream in a heated vessel maintained at a temperature of about 50-300 ° C. Converting,
c) making metal ruthenium by converting at least a portion of the ruthenium oxide to metal ruthenium by reducing the ruthenium oxide with hydrogen;
d) contacting the metal ruthenium with an oxidizing mixture to create a second stream comprising ruthenium tetroxide;
e) removing any oxidizing compound from the second stream of ruthenium tetroxide to obtain high purity ruthenium tetroxide, wherein the high purity ruthenium tetroxide has a purity of approximately 99.9%;
f) A method comprising providing said high purity ruthenium tetroxide to a semiconductor process tool for use in a deposition process.   20. The method of claim 19, further comprising providing the high purity ruthenium tetroxide to a semiconductor process tool upon receipt of the first gas stream.

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