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In a Deposition Chamber US0085O1527B2 (12) United States Patent (10) Patent No.: US 8,501,527 B2 Beck (45) Date of Patent: Aug. 6, 2013 (54) DEPOSITION CHAMBER CLEANING (51) Int. Cl. SYSTEMAND METHOD HOIL 3L/8 (2006.01) BOSB 9/00 (2006.01) (71) Applicant: First Solar, Inc., Perrysburg, OH (US) (52) U.S. Cl. USPC ............................................ 438/95; 134/22.1 (72) Inventor: Markus E. Beck, Scotts Valley, CA (US) (58) Field of Classification Search None (73) Assignee: First Solar, Inc. See application file for complete search history. (*) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 (56) References Cited U.S.C. 154(b) by 0 days. U.S. PATENT DOCUMENTS (21) Appl. No.: 13/689,345 5,779,757 A 7, 1998 Sanghera et al. 8.334,166 B2 12/2012 Beck ............................... 438.95 (22) Filed: Nov. 29, 2012 * cited by examiner (65) Prior Publication Data Primary Examiner — Seahvosh Nikmanesh US 2013/OO956O1 A1 Apr. 18, 2013 (74) Attorney, Agent, or Firm — Dickstein Shapiro LLP Related U.S. Application Data (57) ABSTRACT (62) Division of application No. 13/044.255, filed on Mar. An in-situ method of cleaning a vacuum deposition chamber 9, 2011, now Pat. No. 8,334,166. can include flowing at least one reactive gas into the chamber. (60) Provisional application No. 61/312,083, filed on Mar. 9, 2010. 19 Claims, 7 Drawing Sheets 1. Pulsing a Reactive Gas in a Deposition Chamber Reacting the Reactive Gas with the Deposit Build-up Purging the Chamber with annert Gas U.S. Patent Aug. 6, 2013 Sheet 1 of 7 US 8,501,527 B2 FOW RG Rate G Time FG.1 U.S. Patent Aug. 6, 2013 Sheet 2 of 7 US 8,501,527 B2 Pulsing a Reactive Gas in a Deposition Chamber Reacting the Reactive Gas with the Deposit Build-up Purging the Chamber with an Inert Gas FIG.2 U.S. Patent Aug. 6, 2013 Sheet 3 of 7 US 8,501,527 B2 PG PG2 FOW Rate IG IG G RG Time FG.3 U.S. Patent Aug. 6, 2013 Sheet 4 of 7 US 8,501,527 B2 PG O PG2 O Flow Rate IG IG RG O Time FG.4 U.S. Patent Aug. 6, 2013 Sheet 5 Of 7 US 8,501,527 B2 PG O PG2 O Flow Rate IG G G O RG1 O RG2 O Time FGS U.S. Patent Aug. 6, 2013 Sheet 6 of 7 US 8,501,527 B2 PG O PG2 O FOW Rate IG G O RG O RG2 O Time FG.6 U.S. Patent Aug. 6, 2013 Sheet 7 of 7 US 8,501,527 B2 150 FG.7 US 8,501,527 B2 1. 2 DEPOSITION CHAMBER CLEANING undesirable and impact the film to be grown on the substrate. SYSTEMAND METHOD Thus, the walls and shields need to be cleaned periodically. Cleaning is typically done by removing the shields and CLAIM OF PRIORITY cleaning them either mechanically (e.g. bead blasting, brush ing) or through chemical immersion. These cleaning proce This application is a divisional of U.S. patent application dures can adversely affect a reduction in equipment availabil Ser. No. 13/044,255, filed on Mar. 9, 2011, now U.S. Pat. No. ity (uptime). In order for a deposition process to be an 8.334,166, which claims priority to U.S. Provisional Patent economically viable process in Volume manufacturing appli Application No. 61/312,083, filed on Mar. 9, 2010, which are cations, it is desirable to minimize equipment downtime asso 10 ciated with cleaning. One approach to minimizing cleaning incorporated by reference in their entireties. downtime is to simplify the process of removing and replac ing shields. These fast-change shields can be effective in TECHNICAL FIELD reducing preventative maintenance downtime. However, fur This invention relates to a system and method of cleaning ther improvement is required for cost effective deposition 15 process, particularly in cost sensitive applications. A new a deposition chamber. method and system are developed to address cleaning depo sition chamber Surfaces coated with deposition materials. BACKGROUND An in-situ deposition chamber cleaning method can be used to remove the deposit build-up by deposition processes Deposition methods can result in film growth not only such as ALD and CVD. Examples, of films formed by such covering the substrate to be coated, but also the reaction deposition processes can include metal chalcogenides. chamber walls and shields. For example, a first precursor can Examples of metal chalcogenides formed on deposition form a layer on a deposition chamber Surface and can react chamber surfaces include aluminum oxide (Al2O), alumi with a second precursor to form a layer of a material on a num Sulfide (Al2S), aluminum selenide (Al-Sea) (or combi deposition chamber Surface. This, in turn, can lead to buildup 25 nations thereof), indium oxide (In O), indium sulfide of deposits on the chamber walls and shields over time. (InS), indium selenide (InSes) (or combinations thereof), or zinc oxide (ZnO), Zinc sulfide (ZnS), or zinc selenide DESCRIPTION OF DRAWINGS (ZnSe) (or combinations thereof), or titanium oxide (TiO), titanium sulfide (TiS), or titanium selenide (TiSea) (or com FIG. 1 is a schematic depicting the gas pulse sequence of a 30 binations thereof). The in-situ cleaning method can clean the manufacturing process. chamber wall and shield, without removal of the shields from FIG. 2 is a flowchart depicting the steps of a method for the reactor. A goal of this in-situ cleaning method is to provide cleaning a deposition chamber. for more frequent cleaning cycles thereby reducing the par FIG. 3 is a schematic depicting the gas pulse sequence of a ticle generation and associated yield and process perfor manufacturing process. 35 mance problems. Another goal of this alternate cleaning FIG. 4 is a schematic depicting the gas pulse sequence of a method is to improve deposition tool availability by providing manufacturing process. a fast chamber cleaning method that does not require tool FIG. 5 is a schematic depicting the gas pulse sequence of a downtime. Specifically, it can clean the chamber chemically manufacturing process. in-situ rather than mechanically or chemically ex-situ. In FIG. 6 is a schematic depicting the gas pulse sequence of a 40 Some embodiments, a reactive gas, Such as gas phase hydro manufacturing process. gen chloride (HCl), can be flown through the reactor. The FIG. 7 is a schematic depicting a deposition system. reactive gas can include any suitable gas that can react with the deposits on the chamber walls and shields in Sucha way as DETAILED DESCRIPTION to remove the deposited film. 45 In one aspect, a method of cleaning a deposition chamber Atomic layer deposition (ALD) is a thin film deposition can include pulsing a reactive gas including a hydrogen halide technique that is based on the sequential use of a gas phase into a deposition chamber containing a metal chalcogenide chemical process. By using ALD, film thickness depends formed on a deposition chamber Surface to form a purgable only on the number of reaction cycles, which makes the material. The method can include purging the purgable mate thickness control accurate and simple. Unlike chemical vapor 50 rial from the deposition chamber. deposition (CVD), there is less need of reactant flux homo The purgable material can include forming a vapor. The geneity, which gives large area (large batch and easy scale-up) purgable material can include a particulate. The hydrogen capability, excellent conformality and reproducibility, and halide can include hydrogen chloride, hydrogen bromide, simplifies the use of Solid precursors. hydrogen iodide, or hydrogen fluoride. Purging the purgable Manufacturing a semiconductor device can include a thin 55 material from the deposition chamber can include pulsing an film deposition process. Many deposition methods inadvert inert gas into the deposition chamber to flush the purgable ently result in film growth not only covering the Substrate to material out of the chamber. The method can include heating be coated, but also the reaction chamber walls and shields. For the deposition chamber to maintain the purgable vapor mate example, in an atomic layer deposition or chemical vapor rial as a vapor. The method can include introducing a chemi deposition, all surfaces suitable to allow for adsorption of the 60 cally reactive plasma into the deposition chamber to react first precursor and providing conditions to allow the chemical with metal chalcogenide. reaction to occur with the second precursor. This can inad The method can include pulsing a second reactive gas into vertently result in film growth not only covering the substrate the deposition chamber after pulsing the reactive gas into the to be coated, but also the reaction chamber walls and shields. deposition chamber. The second reactive gas can include At some point deposition build up on the walls and shields 65 oxygen. The second reactive gas can include an acid. The reaches a critical thickness where film stress results in second reactive gas can include fluorine. The second reactive delamination. The ensuing flaking particles are typically gas can include tetrafluoromethane. US 8,501,527 B2 3 4 As mentioned above, purging the purgable material from As shown below, a reactive gas (RG in FIG. 1), Such as gas the deposition chamber can include pulsing an inert gas into phase hydrogen chloride (HCl), can be pulsed into the depo the deposition chamber. The inert gas can include helium. The sition chamber to react with and remove the metal chalco inert gas can include nitrogen. genide deposit: In another aspect, a method of manufacturing a semicon ductor device can include transporting a Substrate into a depo sition chamber and forming a buffer layer adjacent to the Substrate.
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