In situ treatment of molybdenum oxyhalide by-products in semiconductor processing equipment

Abstract

A method is provided for increasing the efficiency of atomic layer deposition of molybdenum metal by in-situ cleaning and decontamination of molybdenum oxyhalide precursor delivery lines to a deposition chamber. The cleaning process may be performed by pre-treating the delivery lines with at least one surface passivation agent and / or periodically treating the delivery lines with at least one corrosion inhibitor. Also provided is a method for removing oxides from deposited molybdenum films.

Description

[Technical field]

[0001] [Incorporated by reference] A PCT application is being filed contemporaneously herewith as a part of this application. Each application identified in a contemporaneously filed Application Data Sheet to which this application claims benefit or priority is hereby incorporated by reference in its entirety for all purposes. [Background technology]

[0002] Many semiconductor device manufacturing processes involve the deposition of metals such as molybdenum to form conductive films. During the deposition process, contaminants resulting from decomposition of the precursor, precursor impurities, or precursor by-products can clog the pipes or lines that carry the precursor into the deposition chamber. The clogs impede or completely block gas flow in the lines. To remove the contaminants, the deposition must be stopped and the equipment must be dismantled so that the lines can be periodically replaced and / or removed for cleaning. Conventional methods of removing contaminants in this manner are inefficient because they interrupt the continuous operation of the deposition process. Thus, there is a need for an in-situ technique that can purge and / or block undesirable contaminants from delivery lines during the deposition process without inefficient downtime for maintenance to remove molybdenum oxyhalide precursor contaminants.

[0003] The background description provided herein is intended to provide a general overview of the contents of the present disclosure. Work by the currently named inventors within the scope of what is described in this Background section, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are not admitted, expressly or impliedly, as prior art against the present disclosure. Summary of the Invention

[0004] A method is provided for increasing the efficiency of atomic layer deposition of molybdenum metal by in-situ cleaning of precursor delivery lines. The cleaning process may be performed by pre-treating the delivery lines with a surface passivator and / or by periodically treating the delivery lines with a corrosion inhibitor.

[0005] Thus, in a first aspect, the present disclosure encompasses a method of depositing molybdenum metal. In some embodiments, the method includes introducing a molybdenum oxyhalide precursor into a deposition chamber containing a semiconductor substrate via one or more precursor delivery lines, supplying a periodic flow of at least one corrosion inhibitor into the precursor delivery lines, and reacting the molybdenum oxyhalide precursor with at least one reactant to form a molybdenum-containing layer on the semiconductor substrate.

[0006] In some embodiments, the at least one corrosion inhibitor comprises a chemical etchant.

[0007] In some embodiments, the chemical etchant is a tungsten halide or a molybdenum halide.

[0008] In some embodiments, the at least one corrosion inhibitor is chlorine, oxygen, fluorine, hydrogen chloride, hydrogen fluoride, chlorine trifluoride, nitrogen trifluoride, or a combination thereof.

[0009] In some embodiments, the at least one corrosion inhibitor is oxygen and chlorine.

[0010] In some embodiments, oxygen and chlorine are fed sequentially or simultaneously to the precursor delivery lines.

[0011] In some embodiments, the at least one corrosion inhibitor is oxygen and fluorine.

[0012] In some embodiments, oxygen and fluorine are fed sequentially or simultaneously to the precursor delivery lines.

[0013] In some embodiments, the corrosion inhibitor is tungsten hexafluoride (WF 6 ), molybdenum pentachloride (MoCl 5 ), and water (H 2 O) is one of them.

[0014] In some embodiments, the molybdenum oxyhalide precursor is Mo q O n Y m wherein Y is a halogen, n is 1 or 2, q is 1, 2 or 4, and m is 1, 2 or 11.

[0015] In some embodiments, the molybdenum oxyhalide precursor is MoOF 4 , Mo 4 O 11 I, MoO 2 I, MoO 2 Br 2 , MoO 2 Cl 2 , MoOCl 4 , or a combination thereof.

[0016] In some embodiments, at least one reactant is hydrogen, ammonia, diborane, water, hydrogen sulfide, a thiol, an alcohol, an amine, hydrazine, a silane, a disilane, or a combination thereof.

[0017] In a second aspect, the disclosure encompasses a method of depositing molybdenum metal, the deposition method including providing a deposition chamber with one or more molybdenum oxyhalide precursor delivery lines, pre-treating the one or more molybdenum oxyhalide precursor delivery lines with at least one surface passivation agent to form one or more treated molybdenum oxyhalide precursor delivery lines, introducing one or more semiconductor substrates to the deposition chamber, introducing a molybdenum oxyhalide precursor to the deposition chamber via the one or more treated molybdenum oxyhalide precursor delivery lines, and reacting the molybdenum oxyhalide precursor with at least one reactant to form a molybdenum-containing layer on the semiconductor substrate.

[0018] In some embodiments, the molybdenum oxyhalide precursor delivery line or lines are stainless steel or nickel alloy.

[0019] In some embodiments, the molybdenum oxyhalide precursor is Mo q O n Y m wherein Y is a halogen, n is 1 or 2, q is 1, 2 or 4, and m is 1, 2 or 11.

[0020] In some embodiments, the molybdenum oxyhalide precursor is MoOF 4 , Mo 4 O 11 I, MoO 2 I, MoO 2 Br 2 , MoO 2 Cl 2 , MoOCl 4 , or a combination thereof.

[0021] In some embodiments, at least one reactant is hydrogen, ammonia, diborane, water, hydrogen sulfide, a thiol, an alcohol, an amine, hydrazine, a silane, a disilane, or a combination thereof.

[0022] In some embodiments, at least one surface passivation agent is fluorine.

[0023] In a third aspect, the disclosure encompasses a method of atomic layer deposition of molybdenum metal, the method including providing one or more molybdenum oxyhalide precursor delivery lines to a deposition chamber; pre-treating the molybdenum oxyhalide precursor delivery lines with at least one surface passivation agent to form one or more treated molybdenum oxyhalide precursor delivery lines; introducing one or more semiconductor substrates into the deposition chamber;

[0024] The method includes introducing a molybdenum oxyhalide precursor into a deposition chamber via one or more treated molybdenum oxyhalide precursor delivery lines, depositing a molybdenum-containing layer on a semiconductor substrate by reacting the molybdenum oxyhalide precursor with at least one reactant, and supplying a periodic flow of at least one corrosion inhibitor to the molybdenum oxyhalide precursor delivery line.

[0025] In some embodiments, the one or more semiconductor substrates are dummy wafers.

[0026] In some embodiments, the molybdenum oxyhalide precursor delivery line or lines are stainless steel or nickel alloy.

[0027] In some embodiments, the molybdenum oxyhalide precursor is Mo q O n Y m wherein Y is a halogen, n is 1 or 2, q is 1, 2 or 4, and m is 1, 2 or 11.

[0028] In some embodiments, the molybdenum oxyhalide precursor is MoOF 4 , Mo 4 O 11 I, MoO 2I, MoO 2 Br 2 , MoO 2 Cl 2 , MoOCl 4 , or a combination thereof.

[0029] In some embodiments, at least one corrosion inhibitor is a chemical etchant.

[0030] In some embodiments, the chemical etchant is a tungsten halide or a molybdenum halide.

[0031] In some embodiments, the at least one corrosion inhibitor is chlorine, oxygen, fluorine, hydrogen chloride, hydrogen fluoride, chlorine trifluoride, nitrogen trifluoride, or a combination thereof.

[0032] In some embodiments, the at least one corrosion inhibitor is tungsten hexafluoride (WF 6 ), molybdenum pentachloride (MoCl 5 ), and water (H 2 O) is one of them.

[0033] In some embodiments, the at least one corrosion inhibitor is oxygen and chlorine.

[0034] In some embodiments, oxygen and chlorine are fed sequentially or simultaneously to one or more molybdenum oxyhalide precursor delivery lines.

[0035] In some embodiments, the at least one corrosion inhibitor is oxygen and fluorine.

[0036] In some embodiments, oxygen and fluorine are fed sequentially or simultaneously to one or more molybdenum oxyhalide precursor delivery lines.

[0037] In a fourth aspect, the present disclosure encompasses a method including providing one or more molybdenum oxyhalide precursor delivery lines to a semiconductor processing chamber and, after processing one or more semiconductor substrates using the molybdenum oxyhalide precursor, supplying at least one corrosion inhibitor to the one or more molybdenum oxyhalide precursor delivery lines.

[0038] In a fifth aspect, the present disclosure encompasses a method including providing one or more molybdenum oxyhalide precursor delivery lines to a semiconductor processing chamber and pre-treating the one or more molybdenum oxyhalide precursor delivery lines with at least one surface passivation agent prior to processing one or more semiconductor substrates using the molybdenum oxyhalide.

[0039] In a sixth aspect, the present disclosure encompasses a method including providing one or more molybdenum oxyhalide precursor delivery lines to a semiconductor processing chamber; pre-treating the one or more molybdenum oxyhalide precursor delivery lines with at least one surface passivation agent prior to processing one or more semiconductor substrates using a molybdenum oxyhalide precursor; and supplying at least one corrosion inhibitor to the one or more molybdenum oxyhalide precursor delivery lines after processing one or more semiconductor substrates using the molybdenum oxyhalide precursor.

[0040] In a seventh aspect, the disclosure encompasses a method that includes filling a feature by depositing molybdenum in the feature, and after filling the feature, removing oxide from the deposited molybdenum by exposing the deposited molybdenum to a chemical etchant. In some embodiments, the chemical etchant is a tungsten halide or a molybdenum halide. In some embodiments, depositing molybdenum includes sequentially introducing a molybdenum halide and a hydrogen co-reactant into a chamber that contains the substrate. In some embodiments, the hydrogen co-reactant is hydrogen (H 2) or other hydrogen-containing gas.

[0041] These and other aspects are described below with reference to the drawings. [Brief description of the drawings]

[0042] [Figure 1] FIG. 1 is a process flow diagram illustrating the operation of a method for depositing molybdenum metal in conjunction with the periodic use of a corrosion inhibitor in accordance with certain disclosed embodiments.

[0043] [Diagram 2] FIG. 2 is a process flow diagram illustrating the operation of a method for depositing molybdenum metal in conjunction with pre-treatment of the precursor delivery lines with a surface passivator, in accordance with certain disclosed embodiments.

[0044] [Diagram 3] FIG. 3 is a process flow diagram illustrating the operation of a method for depositing molybdenum metal in conjunction with pretreatment of precursor delivery lines with a surface passivator and periodic use of a corrosion inhibitor in accordance with certain disclosed embodiments.

[0045] [Figure 4] FIG. 4 illustrates an example of an apparatus that can be used to implement the methods described herein, in accordance with certain disclosed embodiments.

[0046] [Diagram 5] FIG. 5 shows an example of a feature filled with molybdenum (Mo).

[0047] [Figure 6] FIG. 6 is a process flow diagram illustrating the operation of the molybdenum metal deposition method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] In the following description, numerous specific details are set forth to provide a thorough understanding of each presented embodiment. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail so as not to unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with specific embodiments, it will be understood that there is no intent to limit the disclosed embodiments.

[0049] The embodiments disclosed below describe the deposition of materials onto a substrate, such as a wafer, substrate, or other workpiece. The workpieces may be of various shapes, sizes, and materials. In this application, the terms "semiconductor wafer," "wafer," "substrate," "wafer substrate," and "partially fabricated integrated circuit" are used interchangeably. Those skilled in the art will appreciate that the term "partially fabricated integrated circuit" may refer to a silicon wafer at any of the many stages of integrated circuit fabrication thereon. Wafers or substrates used in the semiconductor device industry typically have diameters of 200 mm, 300 mm, or 450 mm. Unless otherwise noted, the processes recited herein (e.g., flow rates, power levels, etc.) relate to processing of 300 mm diameter substrates or chambers configured to process 300 mm diameter substrates, but may be appropriately scaled for other sized substrates or chambers. In addition to semiconductor wafers, other workpieces for which the embodiments disclosed herein may be used include various articles such as printed circuit boards. The process and apparatus may be used in the manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, and the like.

[0050] By halide is meant the anions of F, Cl, Br, or I.

[0051] As used herein, the term "about" means ±10% of any recited value, unless otherwise specified. As used herein, the term modifies any recited value, range of values, or one or more of the endpoints of a range.

[0052] As used herein, the terms "top," "bottom," "upper," "lower," "above," and "below" are used to establish relative relationships between structures. Use of these terms does not indicate or require that a particular structure must be in a particular location within the device.

[0053] In this specification, the phrase at least one of A, B, and C should be construed to mean the logical (A or B or C) with a non-exclusive logical OR, and not to mean "at least one of A, at least one of B, and at least one of C."

[0054] "Atomic Layer Deposition" (ALD) refers to a vapor deposition process in which a deposition cycle, preferably multiple consecutive deposition cycles, are performed in a process chamber (i.e., a deposition chamber). Typically, during each cycle, a precursor is chemisorbed to the deposition surface (i.e., the substrate assembly surface or the surface of a previously deposited underlayer, such as material from a previous ALD cycle), forming a monolayer or submonolayer that does not readily react with additional precursors (i.e., a self-limiting reaction). If necessary, a reactant (i.e., another precursor or reactant gas) may then be introduced into the process chamber and used to convert the chemisorbed precursor to the desired material on the deposition surface. Typically, this reactant can react with the already chemisorbed precursor. Additionally, a purge step may be utilized during each cycle to remove excess precursor from the process chamber after conversion of the chemisorbed precursor and / or to remove excess reactant and / or reaction by-products from the process chamber.

[0055] "Deposition" or "vapor deposition" refers to the process of forming a metal layer on one or more surfaces of a substrate from a vaporized precursor composition(s) containing one or more metal-containing compounds. The metal-containing compounds are vaporized and directed to and / or contacted with one or more surfaces of a substrate (i.e., a semiconductor substrate or semiconductor assembly) mounted in a deposition chamber. Typically, the substrate is heated. These metal-containing compounds form a non-volatile, thin, uniform metal-containing layer on the substrate surface(s). One operation of this method is one cycle, and the process can be repeated as many cycles as necessary to obtain the desired metal thickness.

[0056] "Chemical etchant" means a compound used to remove material, such as a layer, by-product, or contaminant, from a surface.

[0057] "Contaminant" means any compound that may be an impurity, decomposition product, or by-product of the gas delivered to the deposition chamber.

[0058] "Delivery line" means process equipment such as piping, tubing, or conduits that may be utilized to transport or convey gases (e.g., reactant(s) and / or precursor(s), etc.). In semiconductor manufacturing processes, precursor delivery lines may be used to transport precursors to a deposition chamber and may be formed from stainless steel or nickel alloys.

[0059] "Surface passivation agent" refers to an agent that renders a surface inactive so that its properties do not change when the surface interacts with other chemicals (e.g., reactants and / or precursors).

[0060] As used herein, "molybdenum metal" or "metallic molybdenum" refers to a material that consists essentially of molybdenum (Mo). Other elements (e.g., C, N, or O) may be present in small amounts in the molybdenum metal (e.g., less than about 15 atomic % total, or less than about 10 atomic %, not including hydrogen). As used herein, "high purity molybdenum metal" refers to molybdenum metal that contains less than about 5% other elements (e.g., less than about 1% other elements), not including hydrogen.

[0061] FIG. 1 shows a schematic of a non-limiting deposition process 100 for deposition of molybdenum metal, including a flushing mechanism that periodically passes a corrosion inhibitor through the molybdenum oxyhalide precursor delivery line. In some embodiments, the deposition process is atomic layer deposition. Atomic layer deposition (ALD) is a technique that uses a sequence of self-limiting reactions to deposit thin layers of material. ALD processes use surface-mediated deposition reactions to deposit films in cycles, layer by layer. As an example, an ALD cycle may include the following operations: (I) precursor delivery / adsorption, (ii) purging the precursor from the chamber, (iii) delivery of a second reactant and optionally igniting a plasma, and (iv) purging by-products from the chamber. Forming a film on the surface of the substrate by reaction of the second reactant with the adsorbed precursor affects the film's composition and properties such as non-uniformity, stress, wet etch rate, dry etch rate, and electrical properties (e.g., breakdown voltage and leakage current). In the ALD deposition of silicon oxide films, the reaction involves reacting an oxygen plasma with carbon and nitrogen to form gas species, oxidizing silicon to silicon oxide, removing small amounts of carbon, nitrogen, and hydrogen impurities, and improving the bonding and densifying the film.

[0062] Unlike chemical vapor deposition (CVD) techniques, ALD processes deposit films layer by layer using surface-mediated deposition reactions. In one example of an ALD process, a substrate surface containing a population of surface active sites is exposed to a gas-phase distribution of a dose of a first precursor (such as a silicon-containing precursor) provided to a chamber housing the substrate. Molecules of the first precursor are adsorbed on the substrate surface and include chemisorbed species and / or physisorbed molecules of the first precursor. It should be understood that when a compound is adsorbed on a substrate surface as described herein, the adsorbed layer may include derivatives of the compound in addition to the compound. For example, an adsorbed layer of a silicon-containing precursor may include derivatives of the silicon-containing precursor in addition to the silicon-containing precursor. After the first precursor is administered, the chamber is evacuated to remove most or all of the first precursor remaining in the gas phase, leaving most or only the adsorbed species remaining. In some examples, the chamber may not be fully evacuated. For example, the reactor may be evacuated so that the partial pressure of the first precursor in the gas phase is low enough to moderate the reaction. A portion of these molecules are reacted with the surface-adsorbed first precursor by introducing a second reactant (such as an oxygen-containing reactant) into the chamber. In some processes, the second precursor reacts immediately with the adsorbed first precursor. In other embodiments, the second reactant reacts only after an activation source is briefly applied. The chamber may then be evacuated again to remove unbound second reactant molecules. As noted above, in some embodiments, the chamber may not need to be fully evacuated. Additional ALD cycles may be used to increase the film thickness.

[0063] In some embodiments, the ALD method includes plasma activation. As described herein, the ALD methods and apparatus described herein may be conformal film deposition (CFD) methods, which are generally described in U.S. Patent Application No. 13 / 084,399, filed April 11, 2011, entitled "PLASMA ACTIVATED CONFORMAL FILM DEPOSITION" (now U.S. Patent No. 8,728,956), and U.S. Patent Application No. 13 / 084,305, filed April 11, 2011, entitled "SILICON NITRIDE FILMS AND METHODS," both of which are incorporated herein by reference in their entireties.

[0064] Returning to Figure 1, in operation 102, a molybdenum oxyhalide precursor is delivered to a deposition chamber through a delivery line. In some embodiments, the delivery line may be heated to a temperature between about 100°C and about 300°C. In some embodiments, the delivery line is a high nickel alloy or electropolished stainless steel.

[0065] The molybdenum oxyhalide precursor has the formula MoO y X z where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and y and z are MoO y X z is a number greater than zero so that a stable compound is formed. Examples of molybdenum oxyhalides include molybdenum dioxide dichloride (MoO 2 Cl 2 ), molybdenum oxide tetrachloride (MoOCl 4 ), molybdenum oxide tetrafluoride (MoOF 4 ), molybdenum dioxide dibromide (MoO 2 Br 2 ), and molybdenum iodide (MoO 2 I, Mo 4 O 11I). It should be understood that, as used herein, the term molybdenum oxyhalide precursor may refer to a molybdenum oxyhalide precursor as described above, or a molybdenum-containing oxyhalide precursor that includes molybdenum, oxygen, a halide, and one or more other elements. In some embodiments, the molybdenum oxyhalide or molybdenum-containing oxyhalide may include multiple different halogens (e.g., F and Cl and / or I and / or Br, etc.).

[0066] The molybdenum halide or molybdenum oxyhalide precursor may also be a mixed halide precursor having two or more halogens.

[0067] In FIG. 1, operation 104 is an in-situ cleaning protocol utilized in some embodiments. As deposition occurs, after a predetermined or preselected number of deposition cycles and / or a predetermined or preselected number of layers or layer thicknesses have been achieved, the flow of molybdenum oxyhalide may be temporarily stopped or slowed to flow a corrosion inhibitor through the delivery lines to clear contaminants from the delivery lines. In some embodiments, the corrosion inhibitor may be flowed through the system when an objective indicator from a monitoring device indicates that it is needed. For example, an increase in temperature or pressure may indicate a clogging that should be addressed. In some embodiments, the corrosion inhibitor may be flowed through the delivery lines simultaneously with the molybdenum oxyhalide precursor.

[0068] In some embodiments, the contaminants may be precursor impurities, precursor by-products, or decomposition products. For example, when the precursor is molybdenum dioxide dichloride, the by-products are MoO 3 , MoO x Suboxides, and / or MoO x Cl y It may contain complexes.

[0069] In some embodiments, the corrosion inhibitor is a chemical etchant that can reduce the accumulation of contaminants. For example, tungsten fluoride (WF 5 ) or tungsten hexafluoride (WF 6 ) and molybdenum chloride ([MoCl 5 ] 2 ), molybdenum tetrafluoride (MoF 4 ), molybdenum pentafluoride (MoF 5 ), molybdenum hexafluoride (MoF 6 ), Molybdenum bromide (MoBr 2 ), molybdenum dichloride (MoCl 2 ), Molybdenum tribromide (MoBr 3 ), molybdenum trichloride (MoCl 3 ), Molybdenum triiodide (MoI 3 ), Molybdenum tetrabromide (MoBr 4 ), or molybdenum hexachloride (MoCl 6 ) and other molybdenum halides.

[0070] In some embodiments, the chemical etchant is chlorine (Cl 2 ), oxygen (O 2 ), fluorine (F 2 ), hydrogen chloride (HCl), hydrogen fluoride (HF), chlorine trifluoride (ClF 3 ), nitrogen trifluoride (NF 3 ), or a combination thereof. Exemplary combinations include chlorine and oxygen, and fluorine and oxygen. In some embodiments, a single corrosion inhibitor may be sufficient. In some embodiments, multiple corrosion inhibitors may be utilized in combination. When etchants are utilized in combination, they may be flowed together (simultaneously) or sequentially (one following the other) through the delivery line.

[0071] In some embodiments, liquid water (H 2O) is used as a corrosion inhibitor and chemical etchant. The delivery lines may be flooded with liquid water. The water is then purged away by heating the delivery lines. The water may help remove metal (iron, nickel, or chromium) contaminants. Hydrates (e.g., MoO 2 Cl 2 The formation of hydrates can be reversed by purging.

[0072] In some embodiments, a corrosion inhibitor may be flowed through the delivery lines followed by a molybdenum precursor to passivate the lines.

[0073] In operation 106, the molybdenum precursor may be reacted with a reactant to deposit molybdenum, as shown in FIG. 1. An example of a reactant is hydrogen (H 2 ), silane (SiH 4 ), diborane (B 2 H 6 ), German (GeH 4 ), ammonia (NH 3 ), and hydrazine (N 2 H 4 ) are mentioned.

[0074] For example, in some embodiments, the trenches or vias may be filled with molybdenum using a molybdenum oxyhalide precursor. The features may be filled with molybdenum by atomic layer deposition (ALD) or chemical vapor deposition (CVD).

[0075] ALD is a surface-mediated deposition technique in which doses of precursors and reactants are introduced sequentially into a deposition chamber. Mo may be deposited using one or more cycles of sequential doses of molybdenum precursors and reactants. MoO 2 Cl 2 is used as a precursor, H 2 may be used as a reducing agent. A dosage of MoO 2 Cl 2 and H 2are sequentially introduced into the deposition chamber with a purge gas, such as argon, flowing between them. In ALD, the temperature of the substrate and the pressure of the chamber may be controlled. For example, the substrate may be heated to 300° C.-800° C. (e.g., 650° C.-750° C.). In some embodiments, the chamber may be pressurized to 10 Torr-90 Torr (e.g., 30 Torr-50 Torr). In some embodiments, the temperature and / or pressure may be used to control the rate of the reaction. In some embodiments, the temperature and / or pressure may be used to control the selectivity.

[0076] In some embodiments, the molybdenum filling may involve CVD. In a CVD process, a molybdenum precursor and a reactant are both in the vapor phase in a deposition chamber. Generally speaking, a CVD process fills features faster than an ALD process. In one example, the precursor is MoO 2 Cl 2 Molybdenum oxychloride such as H 2 In this example, the wafer is exposed to the precursor and the reactant simultaneously, and the precursor and the reactant react to fill the feature with Mo.

[0077] In yet some other embodiments, a pulsed CVD process may be used to fill the features. In a pulsed CVD process, reactants are continuously flowed into the chamber while precursors are simultaneously pulsed into the chamber. For example, H 2 The molybdenum-containing precursor may be intermittently flowed into the chamber while the gas is flowed into the chamber to flow continuously through the chamber. The temperature of the substrate and the pressure within the chamber may be controlled during the CVD operation.

[0078] Returning to Figure 1, operation 108 is the deposition (or processing) of at least one molybdenum-containing layer. In operation 108, the process can be terminated if the desired thickness has been achieved. If the desired thickness has not been achieved, process operations 102 and 106 (and 104, if necessary) are repeated for a number of cycles sufficient to achieve the desired metal thickness.

[0079] In some embodiments, operations 102, 106, and 108 are performed repeatedly to deposit a molybdenum-containing layer on multiple substrates without intervening operation 104. Operation 104 may be performed without any substrates in the deposition chamber, or with only a dummy wafer that does not contain a partially fabricated device.

[0080] FIG. 2 illustrates generally a non-limiting process 200 for deposition of molybdenum metal that includes an in-situ cleaning mechanism that pretreats the molybdenum oxyhalide precursor delivery lines with a surface passivator to prevent the accumulation of contaminants.

[0081] In operation 202, a deposition chamber is provided with a molybdenum precursor delivery line. In some embodiments, the precursor is a molybdenum oxyhalide.

[0082] In operation 204, the precursor delivery lines are first treated (prior to processing) with at least one surface passivation agent before the precursors are transported through the delivery lines to the deposition chamber in operation 206. In some embodiments, the surface passivation agent is fluorine. In some embodiments, the surface passivation agent is a fluorocarbon or a chlorofluorocarbon. In some embodiments, a combination of surface passivation agents may be utilized.

[0083] In some embodiments, a surface passivator coats the interior of the delivery lines to prevent the accumulation of contaminants.

[0084] In operation 208, the precursor and reactant react to deposit a molybdenum-containing layer.

[0085] 3 illustrates generally a non-limiting process 300 for deposition of molybdenum metal that includes a two-pronged in-situ cleaning mechanism. A deposition chamber configured with a precursor delivery line (operation 302) pre-treats the molybdenum oxyhalide precursor delivery line with a surface passivator in operation 304, and then periodically flushes the delivery line with a corrosion inhibitor in operation 308 as needed when cycles of layer deposition occur (represented as operations 306 and 310).

[0086] In some embodiments, the in-situ cleaning methods described herein may be utilized in conjunction with filters, moisture mitigation units, or other purification equipment to ensure a robust system for semiconductor production.

[0087] As mentioned above, the etching and surface passivation operations can be performed in-situ without removal and replacement. Device

[0088] 4 is a schematic diagram of one embodiment of an ALD process station 400 having a process chamber 402 for maintaining a low pressure environment. In some embodiments, multiple ALD process stations may be included in a common low pressure process tool environment. In some embodiments, one or more hardware parameters of the ALD process station 400, including those discussed in detail below, may be programmatically adjusted by one or more computer controllers 450. In some such embodiments, the process chamber may be a single station chamber.

[0089] The ALD process station 400 is in fluid communication with a reactant delivery system 401 for delivering process gases to a distribution showerhead 406. The reactant delivery system 401 includes a mixing vessel 404 for blending and / or conditioning process gases, such as a Mo precursor-containing gas, a hydrogen-containing gas, argon or other carrier gas, or other precursor-containing gas, for delivery to the showerhead 406. One or more mixing vessel inlet valves 420 may control the introduction of process gases to the mixing vessel 404. In various embodiments, deposition of the initial Mo layer occurs in the process station 400, and in some examples, other operations, such as in-situ cleaning or Mo gap filling, may occur in the same station or another station of the multi-station processing tool 400.

[0090] As an example, the embodiment of FIG. 4 includes a vaporization point 403 for vaporizing the liquid reactant that feeds into the mixing vessel 404. In some embodiments, the vaporization point 403 may be a heated vaporizer. In some embodiments, the liquid precursor or liquid reactant may be vaporized in a liquid injector (not shown). For example, the liquid injector may inject pulses of the liquid reactant into a carrier gas stream upstream of the mixing vessel 404. In one embodiment, the liquid injector may vaporize the reactant by flushing the liquid from a higher pressure to a lower pressure. In another example, the liquid injector may atomize the liquid into dispersed microdroplets that are then vaporized in a heated delivery pipe. Smaller droplets vaporize faster than larger droplets, reducing the delay between injection and complete vaporization of the liquid. Faster vaporization may reduce the length of piping downstream from the vaporization point 403. In some scenarios, the liquid injector may be attached directly to the mixing vessel 404. In another scenario, the liquid injectors may be attached directly to the showerhead 406.

[0091] In some embodiments, a liquid flow controller (LFC) upstream of the vaporization point 403 may be provided to control the mass flow rate of liquid for vaporization and delivery to the process chamber 402. For example, the LFC may include a thermal mass flow meter (MFM) located downstream of the LFC. A plunger valve of the LFC may then be adjusted in response to a feedback control signal provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, it may take a second or more for the liquid flow to stabilize through feedback control. This may result in a long time to dose the liquid reactant. Therefore, in some embodiments, the LFC may be dynamically switched between a feedback control mode and a direct control mode. In some embodiments, this may be accomplished by disabling the sense tubes of the LFC and the PID controller.

[0092] The showerhead 406 distributes process gases toward the substrate 412. In the embodiment illustrated in Figure 4, the substrate 412 is shown positioned below the showerhead 406 and resting on a pedestal 408. The showerhead 406 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to the substrate 412.

[0093] In some embodiments, the pedestal 408 may be raised or lowered to expose the substrate 412 to a volume between the substrate 412 and the showerhead 406. In some embodiments, the pedestal 408 may be temperature controlled via a heater 410. The pedestal 408 may be set to any suitable temperature, such as between about 300° C. and about 500° C., during operation to perform the various disclosed embodiments. It will be appreciated that in some embodiments, the height of the pedestal may be programmatically adjusted by a suitable computer controller 450. At the end of the process step, the pedestal 408 may be lowered during another substrate transfer step to remove the substrate 412 from the pedestal 408.

[0094] In some embodiments, the position of the showerhead 406 may be adjusted relative to the pedestal 408 to change the volume between the substrate 412 and the showerhead 406. Additionally, it will be appreciated that the vertical position of the pedestal 408 and / or the showerhead 406 may be changed by any suitable mechanism within the scope of the present disclosure. In some embodiments, the pedestal 408 may include a rotation axis for rotating the orientation of the substrate 412. It will be appreciated that in some embodiments, one or more of these exemplary adjustments may be implemented programmatically by one or more suitable computer controllers 450. The computer controller 450 may include any of the features associated with the controller 450 of FIG. 4 described below.

[0095] In some embodiments employing plasma as described above, the showerhead 406 and pedestal 408 are in electrical communication with a radio frequency (RF) power source 414 and matching network 416 to power the plasma. In some embodiments, the plasma energy may be controlled by controlling one or more of the process station pressure, gas concentration, RF source power, RF source frequency, and plasma power pulse timing. For example, the RF power source 414 and matching network 416 may be operated at any suitable power to form a plasma having a desired composition of radical species. Similarly, the RF power source 414 may provide RF power of any suitable frequency. In some embodiments, the RF power source 414 may be configured to control the high frequency RF power source and the low frequency RF power source independently of each other. Examples of low frequency RF frequencies include, but are not limited to, frequencies between 0 kHz and 900 kHz. Examples of high frequency RF frequencies include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz, or frequencies greater than about 13.56 MHz, greater than 27 MHz, greater than 80 MHz, or greater than 60 MHz. It will be appreciated that any suitable parameter may be adjusted, either discretely or continuously, to provide plasma energy for the surface reactions.

[0096] In some embodiments, the plasma may be monitored in-situ by one or more plasma monitors. In one scenario, the plasma power may be monitored by one or more voltage, current sensors (e.g., VI probes). In another scenario, the plasma density and / or process gas concentration may be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters may be programmatically adjusted based on measurements from such in-situ plasma monitors. For example, OES sensors may be used in a feedback loop to programmatically control the plasma power. It will be appreciated that in some embodiments, other monitors may be used to monitor the plasma and other process attributes. Such monitors include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0097] In some embodiments, instructions to the controller 450 may be provided through input / output control (IOC) sequence instructions. In one example, instructions for setting the conditions of a process step may be included in the corresponding recipe step of the process recipe. In some cases, the process recipe steps may be arranged in sequence such that all instructions for a process step are executed simultaneously with that process step. In some embodiments, instructions for setting one or more reactor parameters may be included in a recipe step. For example, a first recipe step may include instructions for setting the flow rate of an inert gas and / or reactant gas (e.g., Mo precursor), instructions for setting the flow rate of a carrier gas (such as argon), and a time delay instruction for the first recipe step. A subsequent second recipe step may include instructions for adjusting or stopping the flow rate of an inert gas and / or reactant gas, instructions for adjusting the flow rate of a carrier gas or purge gas, and a time delay instruction for the second recipe step. A third recipe step may include instructions for setting the flow rate of an inert gas and / or reactant gas (e.g., Mo precursor), instructions for setting the flow rate of a carrier gas (such as argon), and a time delay instruction for the second recipe step. 2The first recipe step may include instructions to adjust the flow rate of a second reactant gas, such as an inert gas, a carrier gas or a purge gas, instructions to ignite a plasma, and a time delay instruction for the third recipe step. A subsequent fourth recipe step may include instructions to adjust or stop the flow rate of an inert gas and / or a reactant gas, instructions to adjust the flow rate of a carrier gas or a purge gas, and a time delay instruction for the fourth recipe step. It will be understood that these recipe steps may be further subdivided and / or repeated in any suitable manner within the scope of the present disclosure.

[0098] Additionally, in some embodiments, pressure control of the process station 400 may be provided by a butterfly valve 418. As shown in the embodiment of Figure 4, the butterfly valve 418 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of the process station 400 may be adjusted by varying the flow rate of one or more gases introduced to the process station 400.

[0099] Also shown in Figure 4 is a delivery line treatment gas source 430. The delivery line treatment gas source 430 may include one or more corrosion inhibitor and / or surface passivation gas sources, as described above. The delivery line treatment gas source 430 is configured to provide delivery line treatment gas(es) to the process gas delivery line, as described above. The controller may include instructions for performing periodic in-situ etching and / or surface passivation. The instructions may include instructions for heating the delivery line, as described above.

[0100] Another aspect of the present disclosure is to provide a method for preparing a WF 6or other chemical etchants to remove molybdenum oxide. Figure 5 shows an example feature including molybdenum 510 deposited to fill the feature. In some embodiments, molybdenum oxide may be present on exposed surfaces 512 and may be present on seams 514, if present. Exposing the filled feature to a chemical etchant as described removes the oxide.

[0101] 6 is a flow diagram according to certain embodiments. In operation 605, a feature is filled with molybdenum. Filling of the feature with molybdenum is described above in connection with operation 108 of FIG. 1. One example of a feature is a hole or via in a semiconductor substrate or a layer on a semiconductor substrate. For example, the feature may be formed at least partially in a dielectric layer. In some embodiments, the feature may have an aspect ratio of at least about 2:1, at least about 4:1, at least about 6:1, at least about 10:1, at least about 25:1, or more.

[0102] As described above, the features may be filled with molybdenum by atomic layer deposition (ALD) or chemical vapor deposition (CVD). Thermal ALD or plasma-enhanced ALD (PEALD) may be used. Similarly, thermal CVD or plasma-enhanced CVD (PECVD) may be used.

[0103] For example, Mo 2 Cl 2 or MoCl 5 as a precursor, and H 2 may be used as a reducing agent. A dosage of MoCl 5 and H 2 are sequentially introduced into the deposition chamber with a purge gas such as argon flowing between them. In ALD, the substrate temperature and chamber pressure may be controlled. In the PEALD process, the Mo precursor is H 2 It may be used alternately with a plasma generated from the gas.

[0104] In some embodiments, the molybdenum filling may involve CVD. In a CVD process, a molybdenum precursor and a reactant are both in the vapor phase in a deposition chamber. Generally speaking, a CVD process fills features faster than an ALD process. In one example, the precursor is MoO 2 Cl 2 Molybdenum oxychloride such as H 2 In this example, the wafer is exposed to the precursor and the reactant simultaneously, and the precursor and the reactant react to fill the feature with Mo.

[0105] In yet some other embodiments, a pulsed CVD process may be used to fill the features. In a pulsed CVD process, reactants are continuously flowed into the chamber while precursors are simultaneously pulsed into the chamber. For example, H 2 The molybdenum-containing precursor may be intermittently flowed into the chamber while the gas is flowed into the chamber to flow continuously through the chamber. The temperature of the substrate and the pressure within the chamber may be controlled during CVD operations. All of the above processes may be performed using H 2 , silane (SiH 4 ), and / or diborane (B 2 H 6 ), or plasma generated therefrom, any suitable reducing agent may be used.

[0106] In some embodiments, particularly when deposition is performed at lower temperatures (such as in the case of plasma-based deposition), residual oxides may be present. This may include molybdenum oxides (MoOx) and / or hydrated molybdenum precursors (e.g., MoO 2 Cl 2 H 2 O) form.

[0107] In operation 615, an optional purge is performed. Next, in operation 625, the WF 6 or other chemical etchants described herein (e.g., MoCl 5) is introduced into a chamber housing the substrate including the filled features, which may be referred to as a dose or soak, to remove oxide. The method may be performed in an apparatus such as that described above with reference to FIG.

[0108] The above is a description of an example of the disclosed embodiments in a single or multi-chamber semiconductor processing tool. The apparatus and processes described herein may be used in conjunction with lithographic patterning tools or processes, for example, for the manufacture or production of semiconductor devices, displays, LEDs, photovoltaic panels, etc. Typically, but not necessarily, such tools / processes are used or performed together in a common manufacturing facility. Lithographic patterning of a film typically involves some or all of the following steps, with each step comprising several possible tools: (1) applying a photoresist onto a workpiece (i.e., substrate) using a spin-on or spray-on tool; (2) curing the photoresist using a hotplate, or furnace, or UV curing tool; (3) exposing the photoresist to visible, ultraviolet, or x-ray light using a tool such as a wafer stepper; (4) patterning the resist by growing the resist to selectively remove it using a tool such as a wet bench; (5) transferring the resist pattern to the underlying film or workpiece using a dry etching tool or a plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper. conclusion

[0109] Although the foregoing embodiments have been described in some detail for clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of the present embodiments. Thus, the present embodiments are considered to be illustrative and not restrictive, and the present embodiments are not limited to the details shown herein.

Claims

1. 1. A method for depositing molybdenum metal comprising the steps of: introducing a molybdenum oxyhalide precursor into a deposition chamber containing a semiconductor substrate via one or more precursor delivery lines; providing a periodic flow of at least one corrosion inhibitor to said precursor delivery line; forming a molybdenum-containing layer on the semiconductor substrate by reacting the molybdenum oxyhalide precursor with at least one reactant; A method comprising:

2. 2. The method of claim 1 , The method, wherein the at least one corrosion inhibitor comprises a chemical etchant.

3. 3. The method of claim 2, The method, wherein the chemical etchant comprises a tungsten halide or a molybdenum halide.

4. 2. The method of claim 1 , The method of claim 1, wherein the at least one corrosion inhibitor comprises chlorine, oxygen, fluorine, hydrogen chloride, hydrogen fluoride, chlorine trifluoride, nitrogen trifluoride, or a combination thereof.

5. 5. The method of claim 4, The method of claim 1, wherein the at least one corrosion inhibitor comprises oxygen and chlorine.

6. 6. The method of claim 5, The method wherein the oxygen and the chlorine are supplied to the precursor delivery line sequentially or simultaneously.

7. 5. The method of claim 4, The method of claim 1, wherein the at least one corrosion inhibitor comprises oxygen and fluorine.

8. 8. The method of claim 7, A method wherein the oxygen and the fluorine are supplied to the precursor delivery lines sequentially or simultaneously.

9. 2. The method of claim 1 , The molybdenum oxyhalide precursor is Mo q O n Y m (Y is halogen, n is 1 or 2, q is 1, 2 or 4, and m is 1, 2 or 11).

10. 10. The method of claim 9, The molybdenum oxyhalide precursor is MoOF 4 , Mo 4 O 11 I, MoO 2 I, MoO 2 B 2 , MoO 2 C 2 , MoOCl 4 or a combination thereof and / or wherein at least one reactant comprises hydrogen, ammonia, diborane, water, hydrogen sulfide, a thiol, an alcohol, an amine, hydrazine, a silane, a disilane, or a combination thereof.

11. 2. The method of claim 1 , The corrosion inhibitor is tungsten hexafluoride (WF 6 ), molybdenum pentachloride (MoCl 5 ), and water (H 2 O).

12. 1. A method for depositing molybdenum metal comprising the steps of: Providing one or more molybdenum oxyhalide precursor delivery lines to a deposition chamber; pre-treating the one or more molybdenum oxyhalide precursor delivery lines with at least one surface passivation agent to form one or more treated molybdenum oxyhalide precursor delivery lines; Introducing one or more semiconductor substrates into the deposition chamber; introducing a molybdenum oxyhalide precursor into the deposition chamber via the one or more treated molybdenum oxyhalide precursor delivery lines; forming a molybdenum-containing layer on the semiconductor substrate by reacting the molybdenum oxyhalide precursor with at least one reactant; A method comprising:

13. 13. The method of claim 12, The method, wherein the one or more molybdenum oxyhalide precursor delivery lines comprise stainless steel or a nickel alloy.

14. 13. The method of claim 12, The molybdenum oxyhalide precursor is Mo q O n Y m (Y is halogen, n is 1 or 2, q is 1, 2 or 4, and m is 1, 2 or 11).

15. 15. The method of claim 14, The molybdenum oxyhalide precursor is MoOF 4 , Mo 4 O 11 I, MoO 2 I, MoO 2 B 2 , MoO 2 C 2 , MoOCl 4 or a combination thereof.

16. 13. The method of claim 12, The method, wherein the at least one reactant comprises hydrogen, ammonia, diborane, water, hydrogen sulfide, a thiol, an alcohol, an amine, hydrazine, a silane, a disilane, or a combination thereof.

17. 13. The method of claim 12, The method, wherein said at least one surface passivation agent is fluorine.

18. 1. A method for atomic layer deposition of molybdenum metal, comprising: Providing one or more molybdenum oxyhalide precursor delivery lines to a deposition chamber; pre-treating the molybdenum oxyhalide precursor delivery line with at least one surface passivation agent to form one or more treated molybdenum oxyhalide precursor delivery lines; Introducing one or more semiconductor substrates into the deposition chamber; introducing a molybdenum oxyhalide precursor into the deposition chamber via the one or more treated molybdenum oxyhalide precursor delivery lines; depositing a molybdenum-containing layer on the semiconductor substrate by reacting the molybdenum oxyhalide precursor with at least one reactant; providing a periodic flow of at least one corrosion inhibitor to the molybdenum oxyhalide precursor delivery line; A method comprising:

19. 20. The method of claim 18, The one or more semiconductor substrates include a dummy wafer.

20. 20. The method of claim 18, The method, wherein the one or more molybdenum oxyhalide precursor delivery lines comprise stainless steel or a nickel alloy.

21. 20. The method of claim 18, The molybdenum oxyhalide precursor is Mo q O n Y m (Y is halogen, n is 1 or 2, q is 1, 2 or 4, and m is 1, 2 or 11).

22. 22. The method of claim 21, The molybdenum oxyhalide precursor is MoOF 4 , Mo 4 O 11 I, MoO 2 I, MoO 2 B 2 , MoO 2 C 2 , MoOCl 4 or a combination thereof.

23. 20. The method of claim 18, The method, wherein the at least one corrosion inhibitor comprises a chemical etchant.

24. 24. The method of claim 23, The method, wherein the chemical etchant comprises a tungsten halide or a molybdenum halide.

25. 20. The method of claim 18, The method of claim 1, wherein the at least one corrosion inhibitor comprises chlorine, oxygen, fluorine, hydrogen chloride, hydrogen fluoride, chlorine trifluoride, nitrogen trifluoride, or a combination thereof.

26. 26. The method of claim 25, The method of claim 1, wherein the at least one corrosion inhibitor comprises oxygen and chlorine.

27. 27. The method of claim 26, A method wherein said oxygen and said chlorine are supplied sequentially or simultaneously to said one or more molybdenum oxyhalide precursor delivery lines.

28. 26. The method of claim 25, The method of claim 1, wherein the at least one corrosion inhibitor comprises oxygen and fluorine.

29. 29. The method of claim 28, A method wherein said oxygen and said fluorine are supplied sequentially or simultaneously to said one or more molybdenum oxyhalide precursor delivery lines.

30. 1. A method comprising: Providing one or more molybdenum oxyhalide precursor delivery lines to a semiconductor processing chamber; providing at least one corrosion inhibitor to the one or more molybdenum oxyhalide precursor delivery lines after processing one or more semiconductor substrates using the molybdenum oxyhalide precursor; A method comprising:

31. 1. A method comprising: Providing one or more molybdenum oxyhalide precursor delivery lines to a semiconductor processing chamber; and pre-treating the one or more molybdenum oxyhalide precursor delivery lines with at least one surface passivator prior to processing one or more semiconductor substrates using the molybdenum oxyhalide.

32. 1. A method comprising: Providing one or more molybdenum oxyhalide precursor delivery lines to a semiconductor processing chamber; pre-treating the one or more molybdenum oxyhalide precursor delivery lines with at least one surface passivator prior to processing one or more semiconductor substrates using the molybdenum oxyhalide; providing at least one corrosion inhibitor to the one or more molybdenum oxyhalide precursor delivery lines after processing one or more semiconductor substrates using the molybdenum oxyhalide precursor; A method comprising:

33. 1. A method comprising: filling the feature by depositing molybdenum in the feature; removing oxide from the deposited molybdenum after filling the feature by exposing the deposited molybdenum to a chemical etchant; A method comprising:

34. 34. The method of claim 33, The method of claim 1, wherein the chemical etchant is a tungsten halide.

35. 34. The method of claim 33, The method wherein the chemical etchant is a molybdenum halide.

36. 34. The method of claim 33, The method of claim 1, wherein the oxide comprises a molybdenum oxide and / or a hydrated molybdenum precursor.

37. 34. The method of claim 33, The method, wherein depositing molybdenum in the feature comprises a plasma-enhanced ALD process.

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