KR101270192B1 - Cleaning tantalium-containing deposits from process chamber components - Google Patents

Abstract

The method of cleaning tantalum-containing deposits from the surface of a process chamber component includes immersing the surface of the component in a cleaning solution having a weight ratio of about 1: 8 to 1:30 of HF to HNO ₃ . In another example, the cleaning solution has a molar ratio of about 6: 1 to about 10: 1 of KOH to H ₂ O ₂ . In another example, a cleaning solution suitable for cleaning the copper surface comprises HF and an oxidant in a molar ratio of HF to oxidant of about 6: 1 or greater. Tantalum-containing deposits can be removed from the surface with little corrosion on the surface.

Description

How to clean tantalum-containing deposits from process chamber parts {CLEANING TANTALIUM-CONTAINING DEPOSITS FROM PROCESS CHAMBER COMPONENTS}

The present invention relates to the cleaning and recovery of metal containing residues from process chamber component surfaces.

Cross-reference

This application is a continuation of Brueckner et al. US Patent Application No. 10 / 742,604, "Cleaning Surface Surfaces for Recovering Metal-Containing Composites," filed December 19, 2003 and assigned to Applied Materials. Wang et al., US Patent Application No. 10 / 304,535, entitled "Coated Process Chamber Parts Cleaning Method," filed November 25, 2002 and also assigned to Applied Materials. Both patents are hereby incorporated by reference in their entirety.

In substrate processing, such as semiconductor wafers and displays, the substrate is placed in a process chamber and exposed to activated gas to deposit or etch the material over the substrate. During this process, process residues are generated and deposited on the chamber interior surfaces. For example, in the sputter deposition process, the material sputtered from the target for deposition on the substrate may be deposited ring, cover ring, shadow ring, inner shield, top shield, wall liner. It is also deposited on other component surfaces such as focus rings. Process residues deposited in the next process cycle can "flake off" from the chamber part surface onto the substrate and contaminate the substrate. The deposited process residue therefore has to be cleaned periodically from the chamber surface.

However, it is difficult to clean process deposits containing metal materials such as tantalum from chamber parts, especially when the parts are made of metal containing materials. When tantalum is sputter deposited onto a substrate, some of the sputtered tantalum is deposited on adjacent chamber component surfaces. It is difficult to remove these tantalum process deposits because cleaning solutions suitable for deposit removal frequently react with other metals used to form chamber components, such as titanium. Cleaning tantalum-containing materials from these surfaces can erode parts and require frequent part replacement. Metal surfaces may be particularly problematic when cleaning textured texturing on a metal surface, such as the surface formed by “Lavacoat ^™ ”. If these surfaces have gaps or holes, and the tantalum-containing process residues are sandwiched, it is difficult to remove these residues with conventional cleaning processes.

When tantalum is cleaned using conventional cleaning methods, large amounts of tantalum-containing materials generated during this process are not recovered. In many tantalum deposition processes, only about half of the sputtered tantalum material is deposited on the substrate, and the remainder is deposited on the various component surfaces in the chamber. Conventional cleaning methods have frequently used egg cleaning solutions together with dissolved tantalum material. Thus, after cleaning tantalum from the chamber surface, a large amount of tantalum material is wasted, resulting in a loss of approximately 30,000 pounds per year. Tantalum treated in this way is undesirable from an environmental point of view and costs a great deal because high purity tantalum is expensive and a new cleaning solution must be secured.

In one version, it is desirable to be able to use process chamber components with copper surfaces during substrate processing. Since the copper surface shows a low temperature change, it is possible to minimize the stress between the copper surface and the residue deposited on the surface. However, the use of copper surface parts can be difficult to perform because it is very difficult to clean process residues from the copper surface. This is partly because the copper surface is usually very easily etched and corroded by a cleaning solution that can etch and remove tantalum containing deposits from the part surface. Copper surfaces are also undesirable in that they can easily corrode to cleaning solutions that do not excessively corrode other metal surfaces such as aluminum or stainless steel surfaces.

Therefore, a method of cleaning deposits and metal containing residues such as tantalum containing deposits from the surface of the part without excessively corroding the surface is desirable. It would be even more desirable to clean tantalum-containing deposits from the part surface comprising copper. It is also desirable to reduce the amount of wasted waste tantalum material on the chamber surface. It would be more desirable to recover the cleaning solution used to clean the tantalum containing residues.

The method of cleaning tantalum-containing deposits from the surface of a process chamber component includes immersing the surface of the component in a cleaning solution having a weight ratio of about 1: 8 to 1:30 of HF to HNO ₃ . In this case, tantalum-containing deposits can be removed from the surface of the part with little corrosion on the surface of the part. The surface of the process chamber component then comprises at least one of titanium, stainless steel, aluminum, and tantalum, and the cleaning solution comprises less than about 10 weight percent HF. In another example, the cleaning solution has a molar ratio of about 6: 1 to about 10: 1 of KOH to H ₂ O ₂ . Again, tantalum-containing deposits can be removed from the surface with little corrosion on the surface. The surface of the process chamber component comprises at least one of titanium, stainless steel, aluminum, and tantalum, and the cleaning solution comprises about 5M to about 12M KOH and about 0.5M to about 2M H ₂ O ₂ , which solution Is maintained at a temperature of about 70 ° C. or higher. In another example, a cleaning solution suitable for cleaning the copper surface comprises HF and an oxidant in a molar ratio of HF to oxidant of about 6: 1 or greater. Tantalum-containing deposits can be removed from the surface with little corrosion on the surface. And wherein the oxidizing agent comprises _{HNO 3, H 2 O 2,} H 2 SO 3, and O ₃ of the, including at least one case of the cleaning solution from about 3M to about 20M of HF and from about 0.1M to about 3M of the oxidant .

The features, appearances, advantages, and the like of the presented inventions will be better understood with reference to the following detailed description which shows examples of the invention, the appended claims, and the accompanying schematic drawings. However, it is to be understood that each feature may be used in the invention in general, rather than only in a particular figure, and that the invention may be used in combination in many ways.

1 is a side schematic view of an embodiment of a component having a metal containing deposit on a surface.
2 is a side schematic view of an embodiment of an electrochemical etching apparatus.
3A is a flow chart showing an embodiment of a method of recovering a tantalum containing composite.
3B is a flow chart showing another embodiment of a method for recovering a tantalum containing composite.
4 is a cross-sectional side view of an embodiment of a process chamber having one or more components where metal containing deposits may be cleaned by a cleaning process.
FIG. 5 is a comparative graph of the percent weight loss of copper over time when the copper surface was cleaned with different cleaning solutions comprising HF and HNO _3. FIG.
FIG. 6A is a comparative graph of percent weight loss of copper with cleaning time when the copper surface was cleaned with a cleaning solution containing only HF and an improved cleaning solution containing HF to HNO ₃ in a preselected ratio.
FIG. 6B is a comparative graph of the percent weight loss of tantalum with cleaning time when the tantalum surface was cleaned with the cleaning solution of FIG. 6A.

Process chamber component 22 with surface 20 is cleaned to remove metal containing process deposits 24, such as tantalum containing deposits 24, generated during substrate 104 processing as shown by way of example in FIG. For example, a tantalum containing deposit may include at least one tantalum metal, tantalum nitride, tantalum oxide material. Performing a cleaning process to remove tantalum-containing deposits 24 may reduce contaminant particle formation in the chamber 106, improve substrate yield, and recover tantalum from the cleaning solution. Chamber components 22 to be cleaned are components in which metal and tantalum-containing process deposits 24 accumulate, for example, part of gas delivery system 112 that provides process gas to chamber 106, chamber 106. Gas discharge device for discharging gas from the substrate support 114 for supporting the substrate 104 in the inside, the gas activator 116 for activating the process gas, the chamber outer wall 118, the shield 120, the chamber 106 ( 122) and examples thereof are shown in FIG.

In connection with FIG. 4 showing an embodiment of a physical vapor deposition chamber 106, a cleanable component 22 includes a chamber shield 120 that includes a chamber outer wall 118, and upper and lower shields 120a and 120b. ), Target 124, covering 126, deposition ring 128, support ring 130, insulation ring 132, coil 135, coil support 137, shutter disk 133, There is a clamp shield 141, the surface 134 dl of the substrate support 114. The component 22 may have a surface 20 comprising at least one metal such as titanium, stainless steel, aluminum, copper, tantalum. Surface 20 may also include at least one ceramic material, such as aluminum oxide, aluminum nitride, silicon oxide.

The cleaning step for removing the process deposits 24 may include an acid cleaning solution that may at least partially remove the process deposits 24 from the surface 20 of the part 22. Exposing. The acidic solution can react with the process deposit 24 to form a substance that readily dissolves in the acid solution, for example, to react with the process deposit 24 from the surface 20 of the component 22 to remove the deposit. Acidic substances. However, the acidic solution does not excessively corrode and damage exposed portions of the surface 20 of the part 22 after the process deposit 24 is removed from the part of the part 22. A portion of the surface 20 may be exposed to the acidic solution by contacting or immersing a portion of the surface 20 in the acidic solution. The surface 20 of the coated component 22 may be immersed in the solution for about 3 to 15 minutes, such as approximately 8 minutes, and may be immersed in the solution at different times depending on the composition and thickness of the process deposition material.

The composition of the acidic cleaning solution is determined by the composition of the surface 20 and the composition of the process deposit 24. In one example the acidic solution comprises hydrogen fluoride (HF). Hydrogen fluoride may react with and dissolve impurities accumulated on the surface 20. The acidic solution may additionally or alternatively comprise a non-fluorinated acid such as nitric acid (HNO ₃ ). Non-fluorinating agents may provide less reactive chemicals that result in less corrosion defects in underlying part structures during cleaning and preparation of surface 20. Also in one example, the acidic solution provided for cleaning the surface 20 may include an appropriately low concentration of acidic material to reduce corrosion of the part 22. Appropriate concentrations of the acidic material may be less than about 15M acidic material, for example about 2M to 15M acidic material. For parts 22 comprising a surface 20 comprising aluminum oxide or stainless steel, suitable acidic solutions are approximately 2M to 8M HF, such as HF 5M, and 2M to 15M HNO ₃ , such as about HNO ₃ 12M. Can be done. For parts 22 comprising the surface 20 comprising titanium, suitable acidic solutions may comprise approximately 2M to 10M HNO ₃ . Suitable acidic solutions in this instance may include HF 5M and HNO ₃ 12M.

Cleaning tantalum-containing residues by immersing the surface 20 in a constant ratio of HF to HNO ₃ solution to remove tantalum-containing deposits without substantially corroding the surface 20, especially the metal surface 20. Further cleaning methods have been found that can improve this. It has also been found that setting the HF to HNO ₃ ratio particularly low enough can reduce corrosion of the surface 20, in particular the metal surface 20. Suitable ratios of HF to HNO ₃ may be a ratio of less than about 1: 8 by weight. For example, the cleaning solution may comprise a ratio of HF to HNO ₃ of approximately 1: 8 to 1:30 by weight and may even comprise a ratio of 1:12 to 1:20, such as about 1:15 by weight. . The HF concentration in the solution is preferably maintained from about 2% to 10% by weight, i.e. below about 10%, such as about 5%. The HNO ₃ concentration in the solution is preferably from about 60% to 67% by weight, ie at least 60%, such as around 65%.

Improved cleaning results are believed to be at least in part possible, since HNO ₃ reacts with the surface 20 such as the metal surface and oxidizes and forms a corrosion protection layer over the surface to prevent etching of the surface 20. At sufficiently low ratios HNO ₃ and HF work together to remove tantalum-containing deposits, generally without corrosion of the surface 20. HF etches and dissolves tantalum containing deposits to expose a portion of surface 20. HNO ₃ also corrodes tantalum-containing deposits, even at low etch rates, and further reacts with the exposed portions of surface 20 as strong oxidants and oxidizes the exposed portions to form a corrosion protection layer. Thus, the HNO ₃ surplus can be used to protect the surface 20 from corrosion by maintaining a concentration of HNO ₃ that is sufficiently high relative to the HF concentration in the solution. Cleaning solutions with an improved HF to HNO ₃ ratio that provide sufficiently high concentrations of HNO ₃ for HF are particularly preferred for metal surfaces 20, for example metal surfaces including at least one titanium, stainless steel, aluminum, tantalum. It is suitable for cleaning.

Fresh HF can be added to the cleaning solution to compensate for the depleted HF during the cleaning process. HF in solution is depleted, for example by reacting with tantalum containing deposits 24 to form tantalum fluorinated compounds. Depletion of HF gradually reduces the rate at which tantalum containing deposits are removed from surface 20. The addition of fresh HF allows the removal of tantalum containing deposits 24 from the surface 20 at a desired ratio.

In one example the composition of the cleaning solution may be optimized for cleaning tantalum containing deposits from the metal surface 20 comprising copper. In particular, a cleaning solution comprising hydrogen fluoride (HF) and a preselected molar ratio of oxidant provide improved cleaning of tantalum containing deposits 24 without excessive etching of the copper surface 20, even without almost corrosion of the copper surface 20. It was found that it can. In one example the cleaning solution comprises a molar ratio of HF to oxidant of at least 6: 1, such as approximately at least 9: 1, even at least about 20: 1. For example, the cleaning solution may comprise a molar ratio of HF to oxidant from about 6: 1 to 40: 1, such as approximately 9: 1 to 20: 1. Suitable HF concentrations in the cleaning solution may be at least approximately 3M, such as about 3M to 20M. Suitable oxidant concentrations in the cleaning solution may be less than about 3M, such as from about 0.1M to 3M, and may even be less than about 1M, such as from about 0.1M to 1M. An improved cleaning solution comprising HF and oxidant in a preselected ratio provides good etch selectivity of the tantalum containing deposits 24 on the copper surface 20, such as at least approximately 40: 1, even about 50: 1. Can provide.

Oxidizers include other compounds, such as tantalum-containing deposits, and compounds capable of oxidizing the material and generally include oxygen-containing compounds. In one example, suitable oxidants include nitric acid (HNO ₃ ). Furthermore, in addition to HNO ₃ or hydrogen peroxide, which may be provided as a replacement of _{HNO 3 (H 2 O 2)} , sulfuric acid (H ₂ SO _3), ozone (O ₃₎ at least one material selected from the group consisting of, or better with an oxidizing agent, including those of compound It has been found that cleaning results can be provided. For example, ozone may bubble ozone into the cleaning solution and provide it in the cleaning solution at the desired rate.

In one example of a cleaning solution suitable for cleaning tantalum containing deposits from a part surface comprising copper, the oxidant comprises HNO ₃ . For example, the cleaning solution is (i) HF standard solution by volume to about 45% with a HF concentration of about 49% by weight and (ii) about 70 HNO having an HNO ₃ concentration in weight% ₃ standard solution volume basis about 5% to It can be formed by combining 10%. The remainder of the solution contains water, preferably deionized water. Such solutions include a molar ratio of HF to HNO ₃ from approximately 9: 1 for volume 10% HNO ₃ solutions to 19: 1 for volume HNO ₃ 5% solutions.

The discovery that a solution containing a preselected ratio of HF and an oxidant can clean the tantalum-containing deposits 24 without excessively etching the copper surface 20 suggests that copper is largely due to chemical oxidants such as HNO _3. This was unexpected because it was very sensitive to attack and easily corroded to these formulations. Tantalum-containing deposits 24 are also generally not corroded by a solution containing only HF, preferably at a high rate. However, it has been observed that synergistic effects can be obtained by combining HF and oxidant at preselected molar ratios and using them to obtain improved cleaning of tantalum containing deposits 24. Without limiting this finding to certain chemical mechanisms, it is assumed that the oxidant may serve to speed up the cleaning rate accomplished by HF in solution to etch tantalum containing deposits from the surface 20 at high etch rates. However, it is desirable that the concentration of the oxidant be kept low relative to the HF concentration because excessive amounts of oxidant may result in rapid etching and corrosion of the copper surface 20. Improved HF and oxidant cleaning solutions, because part surfaces 20 comprising metals other than copper, for example aluminum or stainless steel surfaces, often require cleaning solutions with substantially low molar ratios of HF to HNO ₃ . Copper cleaning capability is even more amazing. Thus, cleaning the copper surface 20 with an improved cleaning solution with a preselected proportion of HF and oxidant provides unexpectedly good cleaning results and the component 22 having the copper surface 20 of the substrate process chamber 106. Provide efficient use of

5b to 6b show comparative data on surface cleaning according to various cleaning solutions. FIG. 5 shows comparative data for cleaning solutions with HF and HNO ₃ in relatively low proportions of at least about a preferred molar ratio of about 6: 1. To obtain comparative data, a cleaning solution containing a copper surface 20 of (i) HF and HNO ₃ in a molar ratio of 2: 1 in FIG. 5 and (ii) HF and It was immersed in a cleaning solution containing HNO ₃ in a 1: 2 molar ratio. The solution indicated by line 200 is formed by synthesizing one part of the volume of 49% by volume of one part of the volume of deionized water by the weight of a stock solution of HF. The solution indicated by line 202 is formed by synthesizing 1 part by volume of 49% by weight of the standard solution of HF and 4 parts by volume of deionized water. The weight percentage of copper corroded from each surface was measured at different time intervals during the cleaning process and this weight percentage graph was created as the cleaning duration increased. 5 shows that both cleaning solutions resulted in undesirably high levels of copper surface corrosion and the cleaning solution indicated by line 200 corroded about 20% by weight of copper surface when only about 5 minutes had passed. The solution labeled (202) eroded slightly over 20% by weight after approximately 5 minutes and at least 30% by weight after approximately 10 minutes. Therefore, these cleaning solutions provided undesirable results for the cleaning of the copper surface 20.

6a and 6b show unexpectedly good cleaning results obtained with solutions comprising HF and HNO ₃ with preselected proportions. In FIG. 6A the copper surface comprises (i) a comparative solution containing only about 15 M concentration of HF, indicated by line 204, and (ii) HF and HNO ₃ in a molar ratio of about 20: 1, indicated by line 206. Soaked in an improved solution. The comparative solution was formed by synthesizing one part of the volume of 49% by weight of the standard solution of HF and one part of the volume of deionized water. An improved cleaning solution was formed by synthesizing 10 parts of a volume of 49 wt% of a standard solution of HF, 1 part of a volume of 70 wt% of a standard solution of HNO ₃ and 10 parts of a volume of deionized water. The weight percentage of copper corroded from each surface was measured at different time intervals during the cleaning process and a graph of corroded weight percentage was made with increasing cleaning duration.

6A shows the percent by weight of copper when cleaning the copper surface 20 with the comparative cleaning solution containing HF and with an improved cleaning solution containing both HF and HNO ₃ in a molar ratio of about 20: 1. Decrease. The solution to be compared resulted in no corrosion of the copper surface or only a very small amount of corrosion. The improved solution containing both HF and HNO ₃ resulted in a mild corrosion of the copper surface, while much lower copper weight percent loss, at a much lower rate than the comparative cleaning solution meant by lines 200 and 202 of FIG. woke up. For example, for the improved cleaning solution indicated by line 206, the copper weight percent loss after just over 100 minutes of cleaning time was only slightly lower than 0.15%. In comparison, when the cleaning time was only 5 minutes, the comparative solutions represented by lines 200 and 202 in FIG. 5 resulted in a loss of 20% and 25% of the copper weight percent, which is a preselected HF vs. HNO _3. It was more than 100 times the weight percent loss compared to the improved cleaning solution with the ratio of. Even after about 350 minutes of cleaning time, the improved cleaning solution with the preselected HF to HNO ₃ ratio resulted in a slight loss of about 0.20 wt% copper from the surface 20. Thus an improved cleaning solution with a preselected HF to HNO ₃ ratio provides improved cleaning of the copper surface 20 without substantially corroding the copper surface 20.

FIG. 6B shows the result of exposing the tantalum surface to a cleaning solution having the composition as shown in FIG. 6A. The cleaning result provided by the comparative solution containing about 15 M HF is indicated by line 208 and the cleaning result provided by the improved solution containing both HF and HNO ₃ in a preselected ratio of about 20: 1 It is indicated by 210. To obtain the data of this figure, surfaces containing tantalum were immersed in each cleaning solution and the weight percentage of tantalum corroded from each surface was measured at different time intervals during the cleaning process to determine the cleaning ability of each solution. As the cleaning duration was increased, a corroded weight percentage graph was created for each solution.

The results shown in FIG. 6B show that an improved cleaning solution with a preselected ratio of HF to HNO ₃ provides a very good cleaning of tantalum containing material compared to a solution with only HF. For example, after about 150 minutes of cleaning time, an improved solution of HF and HNO ₃ , denoted by line 210, removed more than 5 wt% tantalum from the surface. In contrast, a solution containing only HF, which is indicated by line 208, removed only about 1 wt% tantalum during the same time. In addition, comparing FIGS. 6A and 6B, it can be seen that an improved cleaning solution containing a predetermined ratio of HF to HNO ₃ shows high selectivity between tantalum and copper. The improved cleaning solution is removed from the surface for the same amount of time as the line 210 of FIG. 6B shows, resulting in only about 0.22 wt% copper loss after approximately 350 minutes of cleaning duration as shown by line 206 of FIG. 6A. Just over 11 wt% of tantalum was removed from the surface. Thus, the improved cleaning solution can provide a selectivity of tantalum to copper of about 50: 1. Thus, solutions with oxidants such as preselected proportions of HF and HNO ₃ provide improved results for effectively cleaning tantalum-containing residues from the part surface, including copper, with almost no corrosion of the part surface.

In another version tantalum containing deposits 24 may be cleaned from the surface 20 by dipping the surface 20 in a solution comprising KOH and H ₂ O ₂ . The cleaning solution has a certain ratio of KOH to H ₂ O ₂ selected to remove tantalum containing deposits without substantially corroding the surface 20, especially the metal surface. Suitable ratios of KOH to H ₂ O ₂ are from about 6: 1 to 10: 1, such as about 7.5: 1 in moles. Lower or higher ratios than the preferred ratio ranges may reduce selectivity for tantalum containing deposits and may result in etching and corrosion on surface 20, respectively. Suitable KOH concentrations in the solution are, for example, about 5M to 12M and even about 5M to 10M, such as 7M. Suitable H ₂ O ₂ concentrations in the solution are for example from about 0.5M to 2.5M and even from 0.5M to 2M, such as about 1M. It has also been found that maintaining an appropriate temperature of the cleaning solution comprising KOH and H ₂ O ₂ can improve the removal of tantalum containing deposits 24 by increasing the deposition removal rate. Suitable temperatures of the cleaning solution are from about 80 ° C. to 95 ° C., even at least about 70 ° C., such as at least about 90 ° C.

In another cleaning example, the metal surface 20 is cleaned by an electrochemical etching process. In this process the surface 20 of the component 22 acts as an anode as shown by way of example in FIG. 2 and is connected to the positive electrode 31 of the voltage source 30. The metal surface 20 is immersed in an electrochemical electrolyzer 33 with an electrolytic solution containing an electrolyte. The electrochemical electrolyser solution may also include, or instead include only, an etchant that selectively etches at least one or more tantalum containing deposits such as HF, HNO ₃ , KOH, H ₂ O ₂ . For example, the electrochemical electrolyzer may comprise one of the HF / HNO ₃ cleaning solution or the KOH / H ₂ O ₂ cleaning solution described above. The electrolyser solution may also include other cleaning agents such as HCl, H ₂ SO ₄ , methanol. In one example, the electrolyzer etches tantalum containing deposits selectively and electrochemically with a solution comprising HF, H ₂ SO ₄ , methanol. The cathode 34 connected to the negative electrode of the voltage source 30 is also immersed in the electrolytic cell 33. Applying a bias voltage to the cathode 34 and the metal surface 20 from the voltage source 30 causes a change in the oxidation state of the tantalum-containing residue on the surface 20, which causes the tantalum-containing deposit 24, such as tantalum metal, to change. The tantalum containing deposits 24 may be etched from the surface 20 by changing them into ionic forms that can be dissolved in an electrochemical etch solution. Etching process conditions, such as the voltage applied to the metal surface 20, the pH of the electrochemical etching solution, and the temperature of the solution, are generally used to selectively remove tantalum containing deposits from the metal surface 20 without corrosion of the metal surface 20. Preferably maintained.

This cleaning method may be particularly suitable for the textured surface 20 as shown by way of example in FIG. 1. The part 22 with the textured surface reduces the generation of particles in the process chamber by providing a "sticky" surface to which process residues adhere. In one example, part 22 cleaned of a tantalum-containing deposit is described in US Patent Application No. 10 / 653,713, "Forming and Cleaning Chamber Parts with Textured Surfaces", for example, in West et al., Filed 9/2/2002. And US patent application Ser. No. 10 / 099,307, filed on March 13, 2002, and in US patent application Ser. No. 10 / 622,178, filed on July 17, 2003. It encompasses parts with surfaces textured by the "Lavacoat ^™ " process, such as the parts described, all of which are commonly assigned to Applied Materials, Inc. and are hereby incorporated by reference in their entirety. Part 22 is also commonly assigned to Applied Materials, and is described by way of example in US Patent Application No. 10 / 304,535 to Wang et al. Filed on 11/25/2002, which is hereby incorporated by reference in its entirety. Coated parts having a textured surface, such as a plasma spray coating or a twin wire arc spray coating.

The “Lavacoat ^™ ” textured metal surface 20 is formed by generating an electromagnetic energy beam and directing the beam to the surface 20 of the component 22. The electromagnetic energy beam may be an electron beam as much as possible, but may also include protons, neutrons, and X-rays. The electron beam is generally focused at a portion of the surface 20 for a period of time during which the beam interacts with the surface 20 to form features on the surface. It is believed that the beam rapidly heats a portion of the surface 20 and in some cases heats to the melting point of the surface material to form a feature. Rapid heating ejects a portion of the surface material outward, thereby forming a depression 23 in the area where the material is ejected and forming a protrusion 25 in the area where the ejected material is redeposited. After the desired features have been formed in the site, the beam is scanned into other areas of the component surface 20 to form features in the new site. The final surface 20 may comprise a honeycomb structure of depressions 23 and protrusions 25 formed on the surface 20. The features formed by this method are largely visible in size and the depression diameter can range from about 0.1 mm to 3.5 mm, such as from about 0.8 to 1.0 mm. The “Lavacoat ^™ ” textured surface 20 has an overall surface roughness average from about 2500 microinches (63.5 micrometers) to 4000 microinches (101.6 microns), which is an average line of features formed along the surface 20. The absolute value of the displacement from.

Immediate cleaning methods provide surprisingly good results for cleaning such textured surfaces with almost no corrosion of the surface 20. For example, for a textured metal surface 20 formed of titanium, the cleaning method described above may corrode titanium from the metal surface 20 to less than about 1 mg / cm 2 per hour and clean the tantalum-containing residue from the surface 20. . In contrast, existing tantalum cleaning processes may corrode titanium at least about 5 mg / cm 2 from the titanium surface of the part 22. As another example, a solution of KOH and H ₂ O ₂ with a selected molar ratio of about 6: 1 to 10: 1 and a temperature of about 80 to 95 ° C. may cause the tantalum-containing deposit to be less than the rate at which titanium part surface 20 is corroded. It can be cleaned at a rate 20 times faster, which makes it possible to clean the surface 20 generally without excessive corrosion.

Once cleaning of the component surface 20 is completed, the cleaning solution may be treated to recover metal containing materials such as tantalum containing materials, which may be at least one or more tantalum metals or tantalum oxides. Recovering tantalum-containing materials from the cleaning solution can reduce environmental pollution from tantalum waste and also reduce the cost of proper disposal of tantalum waste. The recovered tantalum containing material may be reused in a substrate process, for example the recovered tantalum material may be used to form a tantalum containing target for a physical vapor deposition process. The cleaning solution used in addition to tantalum recovery can be treated for reuse of the cleaning solution. For example, the cleaning solution can be treated to recover a reusable solution of HF and HNO ₃ .

A flow chart showing an example of a component cleaning and tantalum containing material recovery method is shown in FIG. 3A. In the first step of this method, the part surface 20 is cleaned by immersion in a cleaning solution, which dissolves tantalum and other metal containing residues in the solution to form tantalum and metal containing composites, respectively. After the part surface 20 is cleaned, a precipitant is added to the cleaning solution to precipitate the metal containing composite from the solution and form a mixed solid. Mixed solids include tantalum containing composites such as tantalum oxide and may also include other metal containing composites such as composites comprising aluminum, titanium, iron. In one example, the cleaning solution may be recovered and reused to clean the next part 22 once it has been precipitated and recovered from the mixed solid solution as indicated by the arrow in FIG. 3A. In one way of precipitating the mixed solids, the cleaning solution is neutralized by adding a precipitant comprising an acid or base which will change the pH of the solution from about 1 pH or less to 7 pH. For example, in the case of a cleaning solution comprising HF and HNO ₃ , a base may be added to neutralize the solution. In the case of a cleaning solution comprising KOH and H ₂ O ₂ , an acid may be added to neutralize the solution. Suitable neutralizing acids may include at least one HNO ₃ , H ₂ SO ₄ , H ₃ PO ₄ . Suitable neutralizing bases may include at least one NaOH, KOH, CaCO ₃ . The mixed solids are then separated from the cleaning solution, for example by filtering the mixed solids from the solution.

A metal selective acid solution is added to the mixed solid to separate the tantalum containing composite from other metal containing parts. The metal selective acid solution comprises a metal selective acid which dissolves the metal containing compound substantially without dissolving the tantalum containing compound in the acid solution. Suitable metal selective acids can include, for example, HCl. Solid tantalum containing composites are separated from acid solutions with dissolved metal containing composites, for example, by filtering tantalum containing solids or by gently pouring the acid solution from the tantalum containing solids. Tantalum containing composites can then be converted to tantalum oxide, for example by heating.

However, another method of component cleaning and recovery of tantalum containing material is shown in the flowchart of FIG. 3B. The component surface 20 is cleaned by immersing the surface 20 in a cleaning aqueous solution to dissolve the tantalum containing composite from the surface 20. After surface cleaning, the tantalum-containing composite is removed from the cleaning solution by a liquid to liquid extraction process. The extraction process involves combining the cleaning aqueous solution with an organic solution that is almost non-miscible. The organic solution is a solution in which the tantalum-containing compound is very well dissolved and a solution from which the tantalum-containing compound can be extracted from an aqueous solution. Suitable organic solutions for extracting tantalum-containing compounds are, for example, at least one methyl isobutyl ketone, diethyl ketone, cyclohexone, diisobutyl ketone It may include tributyl phosphate. Once the tantalum-containing composite is extracted into an organic solution, the organic and aqueous solutions are separated by, for example, dividing the two solutions into separate organic, aqueous phases and draining one solution from the other. The separated aqueous solution can be maintained and reused as a cleaning solution as indicated by the arrow of FIG. 3B. For example, the aqueous solution may include HF and HNO ₃ remaining in the aqueous solution during extraction and may be reused to remove tantalum containing residues from the metal surface 20 in the next cleaning process.

After the extraction process, the tantalum containing composites in the organic solution can be decomposed by thermal hydrolysis. In thermal hydrolysis, the tantalum-containing composite is heated to a temperature at which the composite, such as from about 120 ° C. to 180 ° C., reacts with oxygen to form a tantalum oxide composite. Organic solutions and decomposition reaction by-products can be evaporated from the tantalum oxide composite during the thermohydrolysis process. Alternatively, the organic solution can be removed in a separation step from the tantalum containing compound. Tantalum oxide composites can also be further processed to form tantalum metal, for example by heating the tantalum oxide composites in a furnace.

An example of a suitable process chamber 106 is shown in FIG. 4, which has parts that are cleaned to remove metal containing deposits 24, such as tantalum containing deposits 24. The chamber 106 may be part of a multi-chamber platform (not shown) which has an interconnected chamber population connected by a robotic arm mechanism that moves the substrate between the chambers 106. In the version shown, the process chamber 106 includes a sputter deposition chamber, also referred to as a physical vapor deposition chamber or a PDV chamber, which is one or more tantalum, tantalum nitride, titanium, titanium nitride, copper, tungsten, tungsten nitride, aluminum on the substrate 104. A material such as sputter can be deposited. Chamber 106 includes an exterior wall 118 that constitutes an exterior of process zone 109 that encompasses sidewall 164, bottom wall 166, and ceiling 168. The support ring 130 may be disposed between the sidewall 164 and the ceiling 168 to support the ceiling 168. The other chamber wall encompasses one or more shields 120, which shield the sheath wall 118 from the sputtering environment.

Chamber 106 includes a substrate support 114, which supports the substrate in the sputter deposition chamber. The substrate support 114 may be electrically floating or include an electrode 170, which is biased by a power supply 172, such as an RF power supply. The substrate support 114 can also include a movable shutter disk 133 that can protect the upper surface 134 of the support 114 when the substrate 104 is absent. During operation, the substrate 104 is inserted into the chamber 106 through a substrate loading inlet (not shown) in the sidewall 164 of the chamber 106 and overlies the support 114. Support 114 may be lifted or lowered by a support lift bellows and the lift finger assembly (not shown) lifts or lowers the substrate to or from support 114 while transporting substrate 104 into and out of chamber 106. Can be used.

Substrate 114 may also include one or more coverings 126 and rings, such as deposition rings 128, which at least cover a portion of the upper surface 134 of support 114 to corrode the support 114. Suppress In one example, the deposition ring 128 at least partially surrounds the substrate 104 to protect a portion of the support 114 that is not covered by the substrate 104. Covering 126 surrounds and covers at least a portion of deposition ring 128 and reduces particle deposition of both deposition ring 128 and base support 114.

A process gas, such as a sputtering gas, is inserted into the chamber 106 through a gas release system 112, which encompasses a process gas supply comprising one or more gas sources 174, the gas source comprising a mass flow regulator. Gas is supplied to the conduit 176 with the gas flow control valve 172 to pass the gas at a defined flow rate. Conduit 176 may supply gas to a mixing manifold (not shown) where the gases are mixed to form the desired process gas composition. The mixing manifold supplies gas to gas distributor 180, which has one or more gas outlets 182 in chamber 106. The process gas may include a non-reactive gas such as argon or xenon, which can energetically collide or sputter with the material from the target. The process gas may also include reactive gases, such as one or more oxygen containing and nitrogen containing gases, which may react with the sputtered material to form a layer over the substrate 104. Used process gas and by-products are discharged from chamber 106 through discharge device 122, which includes one or more discharge ports 186 that receive used process gas and send used process gas to discharge conduit 186. 186 has a throttle valve 188 to regulate the gas pressure in the chamber 106. Exhaust conduit 186 supplies gas to one or more exhaust pumps 190. In general, the sputtering gas pressure in chamber 106 is set to a level below atmospheric.

The sputtering chamber 106 further includes a sputtering target 124 facing the surface 105 of the substrate 104 and includes a material such as, for example, at least one or more tantalum and tantalum nitride to be sputtered over the substrate 104. do. The target 124 is electrically insulated from the chamber 106 by an annular insulating ring 132 and is connected to the electricity supply 192. The sputtering chamber 106 also has a shield 120 that will protect the wall 118 of the chamber 106 from sputtered material. Shield 120 includes a cylindrical shape, such as a wall, with upper and lower shield surfaces 120a and 120b that protect the upper and lower portions of chamber 106. In the version shown in FIG. 4, the shield 120 has an upper shield 120a mounted on the support ring 130 and a lower surface 120b fitted to the covering 126. Clamp shields 141 including clamp rings may also be provided to secure the upper and lower shield surfaces 120a and 120b together. Alternative shield arrangements may also be provided, such as inner and outer shields. In one version, one or more of the power supply 192, the target 124, and the shield 120 operate as the gas activator 116 and activate the sputtering gas to sputter material from the target 124. The power supply 192 applies a bias voltage to the target 124 with respect to the shield 120. The electric field generated in the chamber 106 from the applied voltage activates the sputtering gas to form a plasma that energically collides with and impacts the target 124 to sputter material from the target 124 onto the substrate 104. do. A support 114 with an electrode 170 and a support electrode power supply 172 also acts as part of the gas activator 116 by activating and accelerating the sputtered ionized material from the target 124 toward the substrate 104. In addition, a gas activated coil 135 may be provided, which is powered by the power supply 192 and located in the chamber 106 to provide enhanced active gas characteristics such as improved activated gas density. . The gas activated coil 135 may be supported by the coil support 197, which is attached to the shield 120 or other wall in the chamber 106.

The chamber 106 is controlled by a regulator 194 containing program code with instructions to operate the components of the chamber 106 to process the substrate 104 in the chamber 106. For example, the regulator 194 includes a substrate positioning instruction that operates substrate transport with one or more substrate supports 114 to position the substrate 104 within the chamber 106. The gas flow control instructions operate the flow control valve 178 to define the flow of sputtering gas into the chamber 106. The gas pressure regulation instruction is set to operate the discharge throttle valve 188 to maintain pressure in the chamber 106. Gas activator adjustment instructions operate the gas activator 116 to determine the power level of the gas activator. The temperature control instruction is set to adjust the temperature of the chamber 106. Process monitoring instructions are arranged to monitor the process of chamber 106.

Although embodiments of the presented invention have been shown and described, other embodiments may be devised which are indicative of the general functionality of this technology, which embodies the invention presented and is within the scope of the invention as presented. For example, other chamber components may be cleaned in addition to the component examples described herein. In addition to the steps described, additional cleaning and recovery steps may also be performed. In addition, the relative and positional conditions presented in connection with the embodiments are compatible. Therefore, the appended claims should not be limited to the description of the preferred versions, materials, or spatial arrangements described herein to demonstrate the invention.

Claims (1)

A method of cleaning tantalum-containing deposits and recovering tantalum-containing materials from the surface of process chamber components, the method comprising:
(a) dipping the surface of the part in an aqueous cleaning solution comprising acidic or basic, thereby dissolving the tantalum-containing deposit on the surface to form a tantalum-containing mixture in the solution;
(b) treating the cleaning aqueous solution to recover the tantalum-containing mixture,
(i) synthesizing the cleaning solution with an organic solution from which the tantalum-containing mixture can be extracted from the cleaning solution;
(ii) separating the organic solution from the cleaning aqueous solution; And
(iii) pyrohydrolytical decomposition of the tantalum-containing mixture
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A method of cleaning tantalum-containing deposits and recovering tantalum-containing materials from the surface of process chamber components.

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