Apparatus for depositing a thin film using hydrogen peroxide

Abstract

A thin film deposition system is disclosed for forming a thin film on a substrate. The thin film deposition system includes a hydrogen peroxide source. The hydrogen peroxide source includes an electrochemical cell that converts hydrogen gas into hydrogen ion gas. The electrochemical cell converts oxygen and water into a liquid phase complex. The liquid phase complex reacts with the hydrogen ion gas to form hydrogen peroxide.

Description

Technical Field

[0001] The present invention relates to a reaction system for processing semiconductor substrates. Specifically, the present invention relates to a reaction system for depositing an oxide film using hydrogen peroxide as an oxygen source. Background Art

[0002] Atomic layer deposition (ALD) processes can be used to deposit thin films on semiconductor substrates. Such thin films can include zirconium oxide, titanium oxide, tin oxide, aluminum oxide, hafnium oxide, silicon oxide, and any mixtures thereof. When forming a specific thin film with an oxygen component such as an oxide or an oxynitride, an oxygen-containing precursor can be used.

[0003] The oxygen-containing precursor can be water, ozone, or oxygen plasma. Ozone and oxygen plasma may be stronger oxidants than water, but each has problems that affect its ability to form a thin film. For example, ozone lacks hydrogen atoms that can further assist in removing ligands from the growing thin film. Oxygen plasma may have the side effect of damaging the surface; this may result in a reduced ability to coat high aspect ratio features.

[0004] Hydrogen peroxide can make up for the deficiencies of ozone or oxygen plasma because it is a stronger oxidant than water and at the same time provides the hydrogen atoms that ozone lacks. Hydrogen peroxide also does not damage the surface like oxygen plasma does. However, hydrogen peroxide decomposes during storage.

[0005] However, existing methods for generating hydrogen peroxide have drawbacks. U.S. Patent No. 6,767,447 discloses an electrochemical cell using a sodium sulfate solution as an electrolyte. Using a salt solution as an electrolyte is not desirable because the generated particles can cause wafer contamination. U.S. Patent No. 6,712,949 discloses a method: when generating hydrogen peroxide from an acidic electrolyte formed from sulfuric acid, an ion membrane is used to separate the electrodes. The harmful aspects of sulfuric acid stem from the formation of aerosol particles of the acid or the generated salts, resulting in particle defects on the processed wafers. The corrosiveness of any such materials flowing downstream can also damage the reactor components or the wafers in production.

[0006] U.S. Patent No. 5,972,196 discloses an electrochemical cell for generating ozone. Ozone then decomposes in water to produce hydrogen peroxide. The decomposition of ozone needs to be strictly controlled to maintain a constant dose of hydrogen peroxide. In addition, the use of ozone is problematic for the reasons described above, namely that ozone lacks hydrogen atoms that can further assist in removing ligands from the growing thin film.

[0007] Therefore, a system for generating hydrogen peroxide to grow thin films while avoiding decomposition problems is needed. Summary of the Invention

[0008] In at least one embodiment of the present invention, a reaction system configured to form a thin film on a substrate is disclosed. The reaction system includes: a reaction chamber configured to hold the substrate to be processed; a first precursor source configured to supply a first precursor gas to the substrate; an inert gas source configured to supply an inert gas to the substrate; and a hydrogen peroxide source configured to supply a liquid hydrogen peroxide solution as needed, wherein the hydrogen peroxide source includes: an electrochemical cell including: a porous electrolyte, a first gas diffusion layer, a second gas diffusion layer, a catalyst layer, an activated carbon layer, a first membrane layer, and a second membrane layer; a hydrogen source configured to supply hydrogen gas, wherein the hydrogen gas passes through the first gas diffusion layer, the catalyst layer, and the first membrane layer and enters the porous electrolyte; an oxygen source configured to supply oxygen gas, wherein the oxygen gas passes through the second gas diffusion layer, the activated carbon layer, and the second membrane layer and enters the porous electrolyte; and a water source configured to supply water to the porous electrolyte; wherein the catalyst layer converts hydrogen gas into hydrogen ions (H + ) gas; and wherein the activated carbon layer converts oxygen gas into ions that react with water in the porous electrolyte to form a liquid phase (HO2-) complex.

[0009] In at least one embodiment of the present invention, a reaction system configured to form a thin film on a substrate is disclosed. The reaction system includes: a reaction chamber configured to hold the substrate to be processed; a first precursor source configured to supply a first precursor gas to the substrate; an inert gas source configured to supply an inert gas to the substrate; and a hydrogen peroxide source configured to supply a liquid hydrogen peroxide solution as needed, wherein the hydrogen peroxide source includes: an electrochemical cell including: a porous electrolyte, a first gas diffusion layer, a second gas diffusion layer, a catalyst layer, an activated carbon layer, a first membrane layer, and a second membrane layer; a hydrogen source configured to supply hydrogen gas, wherein the hydrogen gas passes through the first gas diffusion layer, the catalyst layer, and the first membrane layer and enters the porous electrolyte; an oxygen source configured to supply oxygen gas, wherein the oxygen gas passes through the second gas diffusion layer, the activated carbon layer, and the second membrane layer and enters the porous electrolyte; and a nitrogen source configured to supply nitrogen (N2) gas to the porous electrolyte; wherein the catalyst layer converts hydrogen gas into hydrogen ions (H + ) gas; and wherein the activated carbon layer converts oxygen gas into ions that form a liquid phase (HO2-) complex.

[0010] To summarize the present invention and the advantages obtained over the prior art, certain objects and advantages of the present invention have been described above. Of course, it should be understood that not all of these objects or advantages may be achieved in accordance with any particular embodiment of the present invention. Thus, for example, those skilled in the art will recognize that the present invention may be practiced or carried out in a manner that achieves or optimizes one advantage or a group of advantages as taught or suggested herein, without necessarily achieving other objects or advantages as taught or suggested herein.

[0011] All of these embodiments are within the scope of the invention disclosed herein. From the following detailed description of certain embodiments with reference to the accompanying drawings, these and other embodiments will become apparent to those skilled in the art, and the invention is not limited to any particular embodiment disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other features, aspects, and advantages of the invention disclosed herein are described below with reference to the drawings of certain embodiments, which are intended to illustrate and not limit the invention.

[0013] Figure 1 A thin film deposition system according to at least one embodiment of the invention is shown.

[0014] Figure 2 A hydrogen peroxide generator for a thin film deposition system according to at least one embodiment of the invention is shown.

[0015] Figure 3 A hydrogen peroxide generator for a thin film deposition system according to at least one embodiment of the invention is shown.

[0016] Figure 4 A thin film deposition system according to at least one embodiment of the invention is shown.

[0017] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the figures may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0018] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Accordingly, it is intended that the scope of the invention disclosed should not be limited by the specific disclosed embodiments described below.

[0019] As used herein, the term "substrate" may refer to any underlying material that can be used or on which a device, circuit, or film can be formed.

[0020] As used herein, the term "chemical vapor deposition" may refer to any process in which a substrate is sequentially exposed to one or more volatile precursors that react and / or decompose on the substrate to produce a desired deposition.

[0021] As used herein, the term "atomic layer deposition" (ALD) can refer to a vapor deposition process in which deposition cycles, preferably multiple consecutive deposition cycles, are carried out in a reaction chamber. Typically, during each cycle, a precursor is chemisorbed onto a deposition surface (e.g., a substrate surface or a previously deposited underlying surface, such as material from a previous ALD cycle), forming a monolayer or sub-monolayer that does not readily react with other precursors (i.e., a self-limiting reaction). Thereafter, if desired, a reactant (e.g., another precursor or a reactive gas) can subsequently be introduced into the processing chamber for converting the chemisorbed precursor into the desired material on the deposition surface. Typically, the reactant is capable of further reacting with the precursor. In addition, after the conversion of the chemisorbed precursor, a purge step can also be utilized during each cycle to remove excess precursor and / or to remove excess reactant and / or reaction by-products from the processing chamber. Further, as used herein, the term "atomic layer deposition" also means to include processes designated by related terms, such as "chemical vapor atomic layer deposition", "atomic layer epitaxy" (ALE), molecular beam epitaxy (MBE), gas-source MBE or organometallic MBE, and chemical beam epitaxy when carried out with alternating pulses of precursor components, reactive gases, and purge gases (e.g., an inert carrier gas).

[0022] As used herein, the terms "film" and "thin film" can refer to any continuous or discontinuous structure and material formed by the methods disclosed herein. For example, "film" and "thin film" can include 2D materials, nanolaminates, nanorods, nanotubes, or nanoparticles, or even partial or complete molecular layers, or partial or complete atomic layers or atomic and / or molecular clusters. "Film" and "thin film" can include materials or layers having pinholes but still being at least partially continuous.

[0023] Embodiments of the present invention are directed to a system for depositing thin films by chemical vapor deposition or ALD processes. Figure 1 A thin film deposition system 100 according to at least one embodiment of the present invention is shown. The thin film deposition system 100 can include: a reaction chamber 110; a substrate holder 110A configured to hold a substrate; a gas distribution system 110B configured to uniformly distribute the gases flowing into the reaction chamber 110 onto the substrate; a hydrogen peroxide source 120; a first precursor source 130; and an inert gas source 140.

[0024] The reaction chamber 110 is shown as having a showerhead arrangement for distributing gases onto the substrate; however, the reaction chamber 110 can alternatively include one of the following: a batch reactor having an injection tube system; a cross-flow reactor; or a spatial reactor.

[0025] The first precursor source 130 can flow a first precursor gas, which includes at least one of the following: silicon precursors such as silane, disilane, trisilane, chlorosilane, dichlorosilane, trichlorosilane, tetrachlorosilane, or tetraethyl orthosilicate; titanium precursors such as titanium tetrachloride (TiCl4), tetraalkoxytitanium, or tetraalkylamidetitanium; indium precursors such as trimethylindium, triethylindium, or tripropylindium; molybdenum precursors such as molybdenum halides or molybdenum alkylamides; vanadium precursors such as vanadium halides or vanadium alkylamides; hafnium precursors such as hafnium chloride, hafnium alkylamide, cyclopentadienylhafnium, cyclopentadienylhafnium alkylamide, or hafnium alkoxide; zirconium precursors such as zirconium chloride, zirconium alkylamide, cyclopentadienylzirconium, cyclopentadienylzirconium alkylamide, or zirconium alkoxide; lanthanum precursors such as lanthanum β-diketonate, lanthanum alkylamide, lanthanum acetamidate, or cyclopentadienyllanthanum; aluminum precursors such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, aluminum chloride, or aluminum alkoxide. The inert gas source 140 can flow an inert gas, which includes at least one of the following: argon (Ar); xenon (Xe); krypton (Kr); helium (He); or nitrogen (N2).

[0026] The first precursor source 130 and the inert gas source 140 are shown to flow the gases combined in the pipeline outside the reaction chamber 110, while the hydrogen peroxide source 120 directly flows hydrogen peroxide into the reaction chamber 110. However, other arrangements are also possible, such as combining all three gas sources into the pipeline outside the reaction chamber, or combining an additional second inert gas source with the hydrogen peroxide source 120.

[0027] The hydrogen peroxide source 120 can also be used in the thin film deposition system 100 for other purposes besides depositing thin films. The hydrogen peroxide source 120 can also be used in processes such as passivating oxides, spin-coating dielectrics, surface cleaning, surface oxidation, or chemical oxidation. Examples of the hydrogen peroxide source 120 have been described in the paper titled "Direct Electrosynthesis of Pure Aqueous H2O2 Solutions Up to 20% by Weight Using a Solid Electrolyte" published by Xia et al. in the Science magazine.

[0028] Figure 2 A hydrogen peroxide source 200 according to at least one embodiment of the present invention is shown. The hydrogen peroxide source 200 can include: a hydrogen source 210; a water source 220; an oxygen source 230; a porous solid electrolyte 240; a first gas diffusion layer 250A; a second gas diffusion layer 250B; an iridium oxide or platinum-loaded carbon catalyst 260A; an activated carbon layer 260B; a first film layer 270A; a second film layer 270B; and a hydrogen peroxide output container 280.

[0029] The hydrogen source 210 supplies hydrogen gas that passes through the first gas diffusion layer 250A. The hydrogen gas reaches the iridium oxide catalyst 260A, which converts the hydrogen gas into hydrogen ions (H + ). The H + gas passes through the first membrane layer 270A and enters the porous solid electrolyte 240. The porous solid electrolyte 240 may include a polymer such as a styrene - divinylbenzene sulfonated copolymer, a Dowex resin, yttria - stabilized zirconia, or an inorganic solid such as a mixed cesium oxide - tungsten phosphate.

[0030] The water source 220 supplies liquid water to the porous solid electrolyte 240. The oxygen source 230 supplies oxygen (O2) that passes through the second gas diffusion layer 250B and enters the activated carbon layer 260B. The oxygen is converted into an ionic form such that it passes through the second membrane layer 270B and contacts the water in the porous solid electrolyte 240, thereby forming a liquid - phase transport (HO2-) complex. The HO2- complex reacts with the H + gas in the porous solid electrolyte 240 to form an H2O2 solution stored in the hydrogen peroxide output container 280.

[0031] The H2O2 solution can be produced on - demand to provide a constant concentration of hydrogen peroxide to the reaction chamber 110. This will prevent the hydrogen peroxide stored in the hydrogen peroxide output container 280 from being stored for too long and causing decomposition problems.

[0032] Figure 3 A hydrogen peroxide source 300 is shown according to at least one embodiment of the present invention. The hydrogen peroxide source 300 may include: a hydrogen source 310; a nitrogen source 320; an oxygen source 330; a porous solid electrolyte 340; a first gas diffusion layer 350A; a second gas diffusion layer 350B; an iridium oxide or platinum - loaded catalyst 360A; an activated carbon layer 360B; a first membrane layer 370A; a second membrane layer 370B; and a hydrogen peroxide output 380.

[0033] The hydrogen source 310 supplies hydrogen gas that passes through the first gas diffusion layer 350A. The hydrogen gas reaches the iridium oxide catalyst 260A, which converts the hydrogen gas into hydrogen ions (H + ). The H + gas passes through the first membrane layer 370A and enters the porous solid electrolyte 340. The porous solid electrolyte 340 may include a polymer such as a styrene - divinylbenzene sulfonated copolymer, a Dowex resin, yttria - stabilized zirconia, or an inorganic solid such as a mixed cesium oxide - tungsten phosphate.

[0034] The nitrogen source 320 in the hydrogen peroxide source 300 replaces the water source 220 in the hydrogen peroxide source 200. The nitrogen source 320 can be connected to a water source to saturate nitrogen with water vapor. This differentiates the hydrogen peroxide source 300 from the hydrogen peroxide source 200. The hydrogen peroxide source 200 produces an aqueous H2O2 solution. The water component in the aqueous H2O2 solution may need to be removed before the H2O2 is used for film deposition. The nitrogen source 320 can avoid this water removal requirement.

[0035] The nitrogen source 320 can supply nitrogen gas (N2) saturated with water vapor into the porous solid electrolyte 340. The water vapor can condense into liquid water, which helps to form a liquid-phase transport.

[0036] The oxygen source 330 supplies oxygen (O2) that passes through the second gas diffusion layer 350B into the activated carbon layer 360B. The oxygen is converted into an ionic form so that it passes through the second membrane layer 370B and contacts the condensed liquid water in the porous solid electrolyte 340, thereby forming a liquid-phase transport (HO2-) complex. The HO2- complex reacts with H + in the gas to form a mixture of H2O2 vapor and gaseous water. This mixture can be homogeneous, eliminating the need for a container at the hydrogen peroxide output 380. This can eliminate the storage requirement and peroxide concentration fluctuations from the start and stop operations of the hydrogen peroxide source 300.

[0037] In another embodiment according to the present invention, the hydrogen peroxide source 300 includes a nitrogen source 320. The nitrogen source 320 provides dry nitrogen (N2) gas and a non-aqueous liquid phase. The non-aqueous liquid phase includes liquids having a very low vapor pressure and a high dipole moment, such as dimethyl sulfoxide (DMSO) or various ionic liquids. This eliminates the need for water as a source for the hydrogen peroxide source 300.

[0038] Due to the presence of N2 gas from the nitrogen source 320, the formed H2O2 vapor is anhydrous. The vapor pressure of this liquid is very low and the dipole moment is high. The low vapor pressure reduces the loss of evaporation of the H2O2 solution. The high dipole moment allows the ionic species generated by the electrodes to dissolve and diffuse within the hydrogen peroxide source 320. The ionic species allow H + gas and the HO2- complex to recombine into hydrogen peroxide.

[0039] Figure 4FIG. 400 shows a thin film deposition system according to at least one embodiment of the present invention. The thin film deposition system 400 may include: a reaction chamber 410; a substrate holder 410A configured to hold a substrate; a gas distribution system 410B configured to uniformly distribute the gas flowing into the reaction chamber 410 onto the substrate; a hydrogen peroxide source 420; a first precursor source 430; a second precursor source 440; and an inert gas source 450. The hydrogen peroxide source 420 can be used in the system to treat the substrate surface (e.g., cleaning or passivation treatment) or clean the interior of the reaction chamber 410.

[0040] The reaction chamber 410 is shown as having a showerhead arrangement to distribute the gas onto the substrate; however, the reaction chamber 410 may alternatively include one of the following: a batch reactor having an injection tube system; a cross-flow reactor; or a spatial reactor.

[0041] The first precursor source 430 may flow a first precursor gas, which includes at least one of the following: a silicon precursor, such as silane, disilane, trisilane, chlorosilane, dichlorosilane, trichlorosilane, tetrachlorosilane, or tetraethyl orthosilicate; a titanium precursor, such as titanium tetrachloride (TiCl4), tetraalkoxytitanium, or tetraalkylamidetitanium; an indium precursor, such as trimethylindium, triethylindium, or tripropylindium; a molybdenum precursor, such as molybdenum halide or molybdenum alkylamide; a vanadium precursor, such as vanadium halide or vanadium alkylamide; a hafnium precursor, such as hafnium chloride, hafnium alkylamide, cyclopentadienylhafnium, cyclopentadienylhafnium alkylamide, or hafnium alkoxide; a zirconium precursor, such as zirconium chloride, zirconium alkylamide, cyclopentadienylzirconium, cyclopentadienylzirconium alkylamide, or zirconium alkoxide; a lanthanum precursor, such as lanthanum β-diketonate, lanthanum alkylamide, lanthanum acetamidate, or cyclopentadienyllanthanum; an aluminum precursor, such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, aluminum chloride, or aluminum alkoxide.

[0042] The second precursor source 440 may provide nitrogen (if a nitride film is formed) or oxygen (if an oxide film is formed). The inert gas source 450 may flow an inert gas, which includes at least one of the following: argon (Ar); xenon (Xe); krypton (Kr); helium (He); or nitrogen (N2).

[0043] The first precursor source 430, the second precursor source 440, and the inert gas source 450 are shown as flowing the gases combined in a pipeline outside the reaction chamber 410, while the hydrogen peroxide source 420 allows hydrogen peroxide to directly flow into the reaction chamber 410. However, other arrangements are also possible, such as combining all three gas sources in a pipeline outside the reaction chamber, or combining an additional second inert gas source with the hydrogen peroxide source 420.

[0044] It should be understood that the configurations and / or methods described herein are exemplary in nature, and these specific embodiments or examples should not be considered restrictive as many variations are possible. The particular routines or methods described herein may represent one or more of any number of processing strategies. Accordingly, the various acts shown may be performed in the order shown, in other orders, or in some cases omitted.

[0045] The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various processes, systems, and configurations, as well as other features, functions, acts, and / or properties disclosed herein, and any and all equivalents thereof.

Claims

1. A reaction system configured to form a thin film on a substrate, comprising: A reaction chamber configured to hold a substrate to be processed; A first precursor source configured to supply a first precursor gas to the substrate; An inert gas source configured to supply an inert gas to the substrate; And A hydrogen peroxide source configured to supply a liquid hydrogen peroxide solution as needed, wherein the hydrogen peroxide source includes: An electrochemical cell including: a porous electrolyte, a first gas diffusion layer, a second gas diffusion layer, a catalyst layer, an activated carbon layer, a first membrane layer, and a second membrane layer; A hydrogen source configured to supply hydrogen gas, wherein the hydrogen gas passes through the first gas diffusion layer, the catalyst layer, and the first membrane layer and enters the porous electrolyte; An oxygen source configured to supply oxygen gas, wherein the oxygen gas passes through the second gas diffusion layer, the activated carbon layer, and the second membrane layer and enters the porous electrolyte; and A nitrogen source configured to supply nitrogen (N2) gas to the porous electrolyte; Among them, the catalyst layer converts hydrogen gas into hydrogen ion (H + ) gas; and Among them, the activated carbon layer converts oxygen into liquid-phase HO2 - ions of the complex.

2. The reaction system according to claim 1, wherein, The porous electrolyte includes at least one of the following: styrene-divinylbenzene sulfonated copolymer, Dowex resin, yttrium-stabilized zirconia, inorganic solid, or mixed cesium oxide-tungsten phosphate.

3. The reaction system according to claim 1, wherein, The catalyst layer includes at least one of the following: iridium oxide or platinum-supported carbon.

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