WO2022127813A1 - 金属硬掩膜刻蚀方法 - Google Patents

金属硬掩膜刻蚀方法 Download PDF

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WO2022127813A1
WO2022127813A1 PCT/CN2021/138270 CN2021138270W WO2022127813A1 WO 2022127813 A1 WO2022127813 A1 WO 2022127813A1 CN 2021138270 W CN2021138270 W CN 2021138270W WO 2022127813 A1 WO2022127813 A1 WO 2022127813A1
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Prior art keywords
etching
gas
hard mask
metal hard
fluorine
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PCT/CN2021/138270
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English (en)
French (fr)
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张宇
黄亚辉
贺小明
刘钊成
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北京北方华创微电子装备有限公司
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Priority to US18/257,751 priority Critical patent/US12100601B2/en
Priority to KR1020237019290A priority patent/KR20230104689A/ko
Priority to JP2023534136A priority patent/JP2023550842A/ja
Publication of WO2022127813A1 publication Critical patent/WO2022127813A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/3065—Plasma etching; Reactive-ion etching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105—After-treatment
    • H01L21/311—Etching the insulating layers by chemical or physical means
    • H01L21/31144—Etching the insulating layers by chemical or physical means using masks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B5/00—Cleaning by methods involving the use of air flow or gas flow
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto 
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32431—Constructional details of the reactor
    • H01J37/3244—Gas supply means
    • H01J37/32449—Gas control, e.g. control of the gas flow
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32431—Constructional details of the reactor
    • H01J37/32798—Further details of plasma apparatus not provided for in groups H01J37/3244 - H01J37/32788; special provisions for cleaning or maintenance of the apparatus
    • H01J37/32853—Hygiene
    • H01J37/32862—In situ cleaning of vessels and/or internal parts
    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105—After-treatment
    • H01L21/31058—After-treatment of organic layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/32—Processing objects by plasma generation
    • H01J2237/33—Processing objects by plasma generation characterised by the type of processing
    • H01J2237/334—Etching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105—After-treatment
    • H01L21/311—Etching the insulating layers by chemical or physical means
    • H01L21/31105—Etching inorganic layers
    • H01L21/31111—Etching inorganic layers by chemical means
    • H01L21/31116—Etching inorganic layers by chemical means by dry-etching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105—After-treatment
    • H01L21/311—Etching the insulating layers by chemical or physical means
    • H01L21/31127—Etching organic layers
    • H01L21/31133—Etching organic layers by chemical means
    • H01L21/31138—Etching organic layers by chemical means by dry-etching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
    • H01L21/32135—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only
    • H01L21/32136—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only using plasmas

Definitions

  • Embodiments of the present invention relate to the field of semiconductor manufacturing, and in particular, to a method for etching a metal hard mask.
  • Particle control capability is an important indicator to measure equipment stability and process stability in the integrated circuit manufacturing process. With the increasing requirements for particle control in the current process, this poses a greater challenge to integrated circuit equipment. .
  • Particle sources mainly include process formation and external introduction.
  • the process formation refers to the particles caused by the process during the process reaction;
  • the external introduction mainly refers to the particles introduced during the loading process of the silicon wafer.
  • the particles introduced during wafer loading have been effectively controlled, but the particles formed by the process have always been a major problem in the extension of etching process technology to lower technology nodes.
  • the etching process of metal hard mask has extremely high requirements on particles.
  • the etching method of metal hard mask adopted in the prior art is used for long-term mass production using etching equipment.
  • the by-products such as hydrogen fluoride (HF) produced will lead to the loss of the inner surface material of the chamber (such as Y 2 O 3 coating), and even the chamber can no longer be used due to the damage of the coating.
  • by-products such as HF are generated It also reacts with the Y 2 O 3 coating to form yttrium-containing particles, causing particle problems as well as defect problems.
  • the present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a metal hard mask etching method, which can reduce the formation of hydrogen fluoride by - products, thereby reducing the amount of Particles resulting from the loss of O3 coating).
  • a metal hard mask etching method wherein a metal hard mask layer and at least one functional film layer are sequentially formed on the wafer surface and along the direction away from the wafer surface,
  • the metal hard mask etching method includes: a plurality of etching processes for sequentially etching at least one of the functional film layers and the metal hard mask layer along a direction close to the surface of the wafer;
  • the etching gas used in at least one etching process includes hydrogen element and fluorine element, and the content of the hydrogen element in the etching gas
  • the ratio to the content of the fluorine element in the etching gas is less than a preset threshold, so as to reduce the generation of hydrogen fluoride by-products
  • the ratio is less than or equal to 1.
  • the ratio is less than or equal to 0.5.
  • the first auxiliary gas is introduced into the process chamber,
  • the first auxiliary gas is used to promote the ionization of the etching gas to reduce the generation of hydrogen fluoride by-products.
  • the first auxiliary gas includes at least one of argon, helium and oxygen.
  • the metal hard mask etching method further includes:
  • At least one cleaning process is performed on the process chamber, and each of the cleaning processes is used to remove at least one reaction by-product generated in the process chamber by the etching process;
  • the reaction by-products include silicon-containing by-products
  • the cleaning gas used in the cleaning process for cleaning the silicon-containing by-products includes a fluorine-containing gas and a second auxiliary gas
  • the second auxiliary gas is used for The generation of fluorine-containing particles in the plasma formed by the ionization of the fluorine-containing gas is reduced.
  • the ratio of the flow rate of the second auxiliary gas to the flow rate of the fluorine-containing gas ranges from 0.3 to 2.
  • the second auxiliary gas includes at least one of argon, helium and oxygen.
  • two functional film layers which are a dielectric material layer and an organic material mask layer that are sequentially arranged on the metal hard mask layer along a direction away from the surface of the wafer;
  • the metal hard mask etching method includes: three etching processes of sequentially etching the organic material mask layer, the dielectric material layer and the metal hard mask layer along a direction close to the surface of the wafer ;
  • the etching gases used in the two etching processes for etching the organic material mask layer and the dielectric material layer respectively include hydrogen element and fluorine element.
  • the etching gases used in the two etching processes for etching the organic material mask layer and the dielectric material layer respectively include CF 4 , CHF 3 and CH 2 F 2 ; and,
  • the gas flow ratio of the CF 4 , CHF 3 and CH 2 F 2 is set so that the content of the hydrogen element in the CF 4 , CHF 3 and CH 2 F 2 in the etching gas is the same as that of the fluorine element
  • the ratio of the content in the etching gas is smaller than the preset threshold.
  • the etching gas used in at least one etching process includes hydrogen element and fluorine element, and
  • the ratio of the content of hydrogen element in the etching gas to the content of fluorine element in the etching gas is less than a preset threshold.
  • FIG. 1 is a block diagram of a flow chart of a method for etching a metal hard mask according to an embodiment of the present invention
  • FIG. 2 is a process diagram of a metal hard mask etching method provided by an embodiment of the present invention.
  • FIG. 3 is another flowchart of a method for etching a metal hard mask provided by an embodiment of the present invention.
  • FIG. 4 is another flowchart of a method for etching a metal hard mask provided by an embodiment of the present invention.
  • Fig. 5 is the graph of the chamber particle and process time that the existing metal hard mask etching method produces
  • FIG. 6 is a graph of chamber particles and process time generated by the metal hard mask etching method according to an embodiment of the present invention.
  • Embodiments of the present invention provide a method for etching a metal hard mask.
  • a metal hard mask layer and at least one functional film layer are sequentially formed on the wafer surface in a direction away from the wafer surface (eg, from bottom to top).
  • the number and types of functional film layers corresponding to different technology generations are also different.
  • there are at least three functional film layers for example, on the basis of the above-mentioned dielectric material layer and organic material mask layer, the An amorphous carbon layer or other organic material film layer is also arranged between the mask layers.
  • a patterned photoresist layer needs to be formed on the uppermost functional film layer to define each functional film layer and metal hard mask during the etching process of the functional film layer. The pattern of the mold layer.
  • the above-mentioned wafer may be a conventional semiconductor substrate, such as a silicon substrate, etc.; or may be a stacked structure including metal layers for interconnects, interlayer dielectric layers, etc.; metal hard masks Layers include, for example, titanium nitride (TiN) layers; dielectric material layers include, for example, silicon dioxide (SiO 2 ) layers and silicon nitride (SiN) layers; organic material mask layers include, for example, silicon anti-reflection layers (Si-arc layers) and bottom anti-reflection layer (B-arc layer).
  • the types of the functional film layers are not particularly limited in the embodiments of the present invention.
  • a method for etching a metal hard mask includes the following steps:
  • etching gas used in at least one etching process includes hydrogen element and fluorine element.
  • the metal hard mask etching method includes: three etching processes of sequentially etching the organic material mask layer, the dielectric material layer and the metal hard mask layer along the direction close to the surface of the wafer.
  • the etching gases used in the two etching processes for etching the organic material mask layer and the dielectric material layer respectively include CF 4 , CHF 3 and CH 2 F2; the etching gas for etching the metal hard mask layer
  • the etching gas used in the etching process includes Cl 2 , CH 4 , and BCl 3 .
  • the etching gases used in the two etching processes for etching the organic material mask layer and the dielectric material layer respectively include hydrogen element and fluorine element.
  • the type of etching gas used in the etching process of each functional film layer can be freely selected according to specific process requirements, which is not particularly limited in the embodiment of the present invention.
  • a by-product of hydrogen fluoride will be generated, which will react with the material on the inner surface of the chamber, and the material on the inner surface of the chamber is the Y 2 O 3 coating material
  • the by-product of hydrogen fluoride reacts with the Y 2 O 3 coating material to form yttrium fluoride (YxFy), because the molecular volume of yttrium fluoride is smaller than that of Y 2 O 3 , resulting in a shallow layer of Y 2 O 3 coating cracks, so that yttrium-containing particles are easily formed.
  • the chamber also needs to be cleaned to remove reaction by-products.
  • the specific process includes: first, the wafer is introduced into the process chamber to perform the etching process; after the etching process is completed, the wafer is passed out of the process chamber, and then the process chamber is cleaned craft.
  • the cleaning gas usually includes nitrogen fluoride (NF 3 ) gas, and the plasma generated by this gas is extremely corrosive, which further penetrates into the Y 2 O 3 coating to produce yttrium fluoride ( YxFy).
  • NF 3 nitrogen fluoride
  • the cleaning gas includes O2 , it will react with the Y2O3 coating to form YOF, which will eventually fall off to form particles.
  • the ratio of the content of hydrogen in the etching gas to the content of fluorine in the etching gas is controlled to be less than a preset threshold.
  • the generation of hydrogen fluoride by-products can be reduced, thereby reducing the generation of particles (such as yttrium fluoride particles) generated by the reaction of hydrogen fluoride by-products with the interior surface material of the chamber (such as yttrium fluoride particles), and reducing the loss of interior surface materials (such as Y 2 O 3 coating) , which can effectively control particle problems and defect problems.
  • the content of hydrogen element in the etching gas and the content of fluorine element in the etching gas specifically refers to the respective content of hydrogen element and fluorine element contained in the etching gas in the process chamber.
  • the ratio of the content of hydrogen element in the etching gas to the content of fluorine element in the etching gas is less than or equal to 1, for example, less than or equal to 0.5.
  • particles eg, yttrium fluoride particles
  • the loss of materials on the inner surface eg, Y 2 O 3 coating
  • the above ratio can be adjusted by adjusting the flow rates of various gases contained in the etching gas.
  • the gas flow rates of the two may be set to 20sccm and 100sccm, respectively.
  • the ratio of the content of hydrogen in the etching gas to the content of fluorine in the etching gas is 0.26, which is less than 1, which can effectively reduce the particles generated by the reaction of hydrogen fluoride by-products with the inner surface material of the chamber.
  • the gas flow rates of the two can be set to 80sccm and 100sccm respectively.
  • the ratio of the content of hydrogen in the etching gas to the content of fluorine in the etching gas is 1, which can also effectively reduce the particles generated by the reaction of hydrogen fluoride by-products with the inner surface material of the chamber.
  • the first auxiliary gas is passed into the process chamber,
  • the first assist gas is used to promote ionization of the etching gas to further reduce the generation of hydrogen fluoride by-products.
  • the etching gas includes CHF 3 gas
  • the first auxiliary gas can promote the further ionization of the CHF 3 gas to form radicals and ions such as CF 2 + and CF 3 +, thereby reducing the generation of hydrogen fluoride by-products.
  • the above-mentioned first auxiliary gas includes at least one of argon, helium and oxygen.
  • oxygen can not only promote the further ionization of CHF 3 gas to form radicals and ions such as CF 2 + and CF 3 + , but also react with H ions to generate HO, which can further reduce the generation of hydrogen fluoride by-products.
  • the above-mentioned metal hard mask etching method further includes the following steps:
  • each of the cleaning processes is used to remove at least one reaction by-product generated in the process chamber by the etching process.
  • the number of cleaning processes and the type of cleaning gas used in each cleaning process may be selected according to the types of reaction by-products generated in the process chamber.
  • the cleaning gas used in the cleaning process for cleaning the silicon-containing by-product includes a fluorine-containing gas and a second auxiliary gas, wherein the fluorine-containing gas includes, for example, NF 3 and SF 6 , etc.
  • the plasma generated by the fluorine-containing gas is extremely corrosive, which further penetrates into the Y 2 O 3 coating to produce yttrium fluoride (YxFy).
  • the above-mentioned second auxiliary gas can be introduced at the same time as the above-mentioned fluorine-containing gas. The generation of yttrium-containing particles formed by the reaction of the fluorine-containing particles with the Y 2 O 3 coating can be reduced.
  • the composition of the plasma formed by the ionization of the second auxiliary gas and the fluorine-containing gas can be controlled by controlling the ratio of the flow rate of the second auxiliary gas to the flow rate of the fluorine-containing gas, so as to achieve cleaning
  • the plasma formed by the ionization of the second auxiliary gas can effectively reduce the generation of fluorine-containing particles (eg, fluorine radicals) in the plasma formed by the ionization of the fluorine-containing gas.
  • the ratio of the flow rate of the second auxiliary gas to the flow rate of the fluorine-containing gas is in the range of 0.3-2. Within this numerical range, it can be ensured that the generation of fluorine-containing particles (eg, fluorine radicals) in the plasma formed by ionization of the fluorine-containing gas can be effectively reduced.
  • the above-mentioned second auxiliary gas includes at least one of argon, helium and oxygen.
  • the following takes the metal hard mask etching method including: sequentially etching the organic material mask layer, the dielectric material layer and the metal hard mask layer along the direction close to the surface of the wafer. Three etching processes and corresponding cleaning processes are taken as an example , the metal hard mask etching method provided by the embodiment of the present invention is described in detail.
  • the metal hard mask etching method includes the following steps:
  • the etching process of the organic material mask layer can adopt the following process parameters:
  • the etching gas can be a gas containing hydrogen and fluorine, such as CF 4 , CHF 3 and CH 2 F 2 ; or, a gas that does not contain hydrogen and fluorine, such as Cl 2 and O 2 , Alternatively include Cl 2 , O 2 and CH 4 .
  • the range of process pressure is 3mT ⁇ 40mT, preferably 5mT ⁇ 20mT; the range of excitation power is 200W ⁇ 2000W, preferably 400W ⁇ 1200W; the range of bias power is 20W ⁇ 500W, preferably 60W ⁇ 200W.
  • the etching gas includes Cl 2 and O 2 , or includes Cl 2 , O 2 and CH 4 , the gas flow rate of Cl 2 is 50sccm ⁇ 200sccm, the gas flow rate of O 2 is 10sccm ⁇ 35sccm, and the gas flow rate of CH 4 is 0sccm ⁇ 20sccm.
  • the etching gas includes CF 4 , CHF 3 and CH 2 F 2 , the gas flow of CF 4 is 0 sccm to 200 sccm, the gas flow of CHF 3 is 0 sccm to 200 sccm, and the gas flow of CH 2 F 2 is 0 sccm to 200 sccm.
  • a first auxiliary gas can also be introduced, for example, the first auxiliary gas includes at least one of Ar, He and O 2 , wherein, the gas flow rate of Ar is 0 sccm-200 sccm, the gas flow rate of He is 0 sccm-300 sccm, and the gas flow rate of O 2 is 0 sccm-150 sccm.
  • the etching process of the dielectric material layer can adopt the following process parameters:
  • the etching gas can be a gas containing hydrogen element and fluorine element, such as CF 4 , CHF 3 and CH 2 F 2 ; wherein, the gas flow rate of CF 4 is 0 sccm-200 sccm, the gas flow rate of CHF 3 is 0 sccm-200 sccm, and the gas flow rate of CHF 3 The gas flow rate of 2 F 2 is 0 sccm to 200 sccm.
  • the total flow rate of the etching gas used in the etching process of the dielectric material layer is consistent with the total flow rate of the etching gas used in the etching process for the above-mentioned organic material mask layer;
  • the range of the process pressure is 3mT ⁇ 80mT, preferably 5mT ⁇ 50mT;
  • the range of excitation power is 200W ⁇ 2000W, preferably 400W ⁇ 1600W;
  • the range of bias power is 20W ⁇ 500W, preferably 60W ⁇ 400W.
  • silicon-containing by-products are formed in the chamber.
  • the etching process of the metal hard mask layer can adopt the following process parameters:
  • the etching gas includes Cl 2 , CH 4 and BCl 3 , wherein the gas flow of Cl 2 is 0 sccm to 200 sccm, the gas flow of CH 4 is 0 sccm to 30 sccm, and the gas flow of BCl 3 is 0 sccm to 200 sccm;
  • a morphology modification gas or an auxiliary gas for realizing other functions can also be introduced at the same time as the etching gas.
  • the morphology modification gas is such as NF 3 and SiCl 4 , etc.
  • the gas flow of NF 3 is 0 sccm to 200 sccm
  • the gas flow of SiCl 4 is 0 sccm to 100 sccm
  • the auxiliary gases for other functions are Ar, He and O 2 , etc.
  • the gas flow of Ar is 0 sccm to 200 sccm
  • the gas of He The flow rate is 0sccm ⁇ 300sccm
  • the gas flow rate of O 2 is 0sccm ⁇ 150sccm.
  • the range of process pressure is 3mT ⁇ 40mT, preferably 5mT ⁇ 20mT; the range of excitation power is 200W ⁇ 2000W, preferably 400W ⁇ 1200W; the range of bias power is 20W ⁇ 300W, preferably 60W ⁇ 200W.
  • metal by-products are formed in the chamber.
  • the hydrogen element in the etching gas is controlled within a range less than a preset threshold, for example, the ratio is in the range of 0 to 1, preferably 0 to 0.5, which can reduce the generation of hydrogen fluoride by-products, thereby reducing hydrogen fluoride by-products Particles (such as yttrium fluoride particles) generated by reacting with materials on the inner surface of the chamber, while reducing the loss of materials on the inner surface of the chamber (such as Y 2 O 3 coatings), can effectively control the problem of particles and defects.
  • the etching gas includes CF 4 , CHF 3 and CH 2 F 2 and the like containing hydrogen element and fluorine element, it can also be passed into the above-mentioned gas.
  • the first auxiliary gas is introduced, and the first auxiliary gas is used to promote the ionization of the etching gas, so as to further reduce the generation of hydrogen fluoride by-products.
  • various by-products formed in the process chamber that is, carbon-containing by-products, silicon-containing by-products and metal by-products, can be Before the etching process is performed on the next wafer, the process chamber is cleaned by the following cleaning methods, including:
  • the cleaning gas includes Cl 2 , and the gas flow is 0 sccm-500 sccm; the process pressure is in the range of 3mT-40mT, preferably 5mT-20mT; the excitation power is in the range of 200W-2000W, preferably 400W-1200W.
  • a cleaning process is performed on the silicon-containing by-products generated by the etching process of the dielectric material layer.
  • the cleaning gas includes NF 3 and SF 6 , wherein the gas flow rate of NF 3 is 0 sccm to 300 sccm, and the gas flow rate of SF 6 is 0 sccm to 100 sccm.
  • the cleaning gas includes a fluorine-containing gas, and the plasma generated by the fluorine-containing gas is extremely corrosive, which further penetrates into the Y 2 O 3 coating to produce yttrium fluoride (YxFy).
  • a second auxiliary gas can be introduced while the above-mentioned fluorine-containing gas is introduced to reduce the generation of fluorine-containing particles (for example, fluorine radicals) in the plasma formed by the ionization of the fluorine-containing gas, thereby The yttrium-containing particles formed by the reaction of the fluorine-containing particles with the Y2O3 coating can be reduced.
  • fluorine-containing particles for example, fluorine radicals
  • the above-mentioned second auxiliary gas includes at least one of Ar, He and O 2 , wherein the gas flow rate of O 2 is 0sccm ⁇ 500sccm, the gas flow rate of Ar is 0sccm ⁇ 500sccm, and the gas flow rate of He is 0sccm ⁇ 500sccm.
  • the ratio of the flow rate of the second auxiliary gas to the flow rate of the fluorine-containing gas ranges from 0.3 to 2. Within this numerical range, it can be ensured that the generation of fluorine-containing particles (eg, fluorine radicals) in the plasma formed by ionization of the fluorine-containing gas can be effectively reduced.
  • the range of the process pressure is 5mT ⁇ 250mT, preferably 20mT ⁇ 90mT; the range of the excitation power is 200W ⁇ 2000W, preferably 800W ⁇ 1800W.
  • the cleaning gas includes O 2 , and its gas flow is 0sccm-500sccm; the process pressure is in the range of 3mT-40mT, preferably 5mT-20mT; the excitation power is in the range of 200W-2000W, preferably 400W-1200W.
  • the present application is not limited to cleaning in the order from the above-mentioned steps S104 to S106.
  • the above-mentioned steps S104 to S106 can also be performed in other orders to realize the cleaning of the above-mentioned various by-products, and the present application does not set this up. limit.
  • FIG. 5 is a graph of chamber particles and process time generated by an existing metal hard mask etching method
  • FIG. 6 is a graph of chamber particles and process time generated by the metal hard mask etching method provided by an embodiment of the present invention.
  • PA is the total number of particles in the process chamber
  • Y 2 O 3 is the number of particles of Y 2 O 3 in the process chamber. Comparing Fig. 5 and Fig. 6, it can be seen that in the existing metal hard mask etching method, the total number of particles generated in the process chamber gradually increases to 70 with the accumulation of process time, and the number of Y 2 O 3 particles increases with the increase of the process time. As the process time accumulates, it gradually increases to 60.
  • the total number of particles generated in the process chamber and the number of Y 2 O 3 particles are controlled at different process times (0-100h) at 10 or less, thereby greatly reducing the particles generated due to the loss of the inner surface material of the chamber (such as Y 2 O 3 coating), which can effectively control the particle and defect problems.
  • the metal hard mask etching method provided by the embodiment of the present invention can be applied to the preparation of logic chip products, such as a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MPU), and the like.
  • logic chip products such as a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MPU), and the like.
  • the etching gas used in at least one etching process includes hydrogen element and fluorine, and the ratio of the content of hydrogen in the etching gas to the content of fluorine in the etching gas is less than a preset threshold.

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Abstract

本发明实施例提供一种金属硬掩膜刻蚀方法，在晶圆表面上，且沿远离所述晶圆表面的方向依次形成金属硬掩模层和至少一个功能膜层，该金属硬掩膜刻蚀方法包括：沿靠近晶圆表面的方向依次对至少一个功能膜层和所述金属硬掩膜层进行刻蚀的多个刻蚀工艺；在所有的对功能膜层进行刻蚀的刻蚀工艺中，有至少一个刻蚀工艺采用的刻蚀气体包括氢元素和氟元素，且氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值小于预设阈值，以减少氟化氢副产物的生成。本发明实施例提供的金属硬掩膜刻蚀方法，其可以减少氟化氢副产物的形成，从而可以减少因腔室内表面材料损耗而产生的颗粒。

Description

金属硬掩膜刻蚀方法 技术领域
本发明实施例涉及半导体制造领域，具体地，涉及一种金属硬掩膜刻蚀方法。
背景技术
颗粒控制能力是集成电路制造工艺中衡量设备稳定性和工艺稳定性的一项重要指标，随着目前工艺制程对颗粒控制的要求越来越高，这就对集成电路设备提出了更大的挑战。
颗粒来源主要包括工艺形成和外界引入。其中，工艺形成是指在工艺反应期间由于工艺导致的颗粒；外界引入主要指在硅片装载过程中引入的颗粒。目前对于晶圆装载过程中引入的颗粒已经得到了有效的控制，但是工艺形成的颗粒一直以来都是刻蚀工艺技术向更低技术节点的延伸过程中的重大问题。
例如，在28nm及以下的工艺制程中，金属硬掩膜的刻蚀工艺对颗粒要求极高，但是，现有技术采用的金属硬掩膜的刻蚀方法，在长期使用刻蚀设备进行量产的过程中，产生的氟化氢(HF)等副产物会导致腔室内表面材料(例如Y 2O 3涂层)损耗，甚至会因涂层损坏致使腔室无法继续使用，同时产生的HF等副产物还会与Y 2O 3涂层反应形成含钇成分的颗粒，引起颗粒问题以及缺陷问题。
发明内容
本发明旨在至少解决现有技术中存在的技术问题之一，提出了一种金属硬掩膜刻蚀方法，其可以减少氟化氢副产物的形成，从而可以减少因腔室内 表面材料(例如Y 2O 3涂层)损耗而产生的颗粒。
为实现本发明的目的而提供一种金属硬掩膜刻蚀方法，在晶圆表面上，且沿远离所述晶圆表面的方向依次形成金属硬掩模层和至少一个功能膜层，
所述金属硬掩膜刻蚀方法包括：沿靠近所述晶圆表面的方向依次对至少一个所述功能膜层和所述金属硬掩膜层进行刻蚀的多个刻蚀工艺；
在所有的对所述功能膜层进行刻蚀的刻蚀工艺中，有至少一个刻蚀工艺采用的刻蚀气体包括氢元素和氟元素，且所述氢元素在所述刻蚀气体中的含量与所述氟元素在所述刻蚀气体中的含量的比值小于预设阈值，以减少氟化氢副产物的生成
可选的，所述比值小于或等于1。
可选的，所述比值小于或等于0.5。
可选的，在所述刻蚀气体包括氢元素和氟元素的刻蚀工艺中，在向工艺腔室通入所述刻蚀气体的同时，向所述工艺腔室通入第一辅助气体，所述第一辅助气体用于促进所述刻蚀气体的电离，以减少氟化氢副产物的生成。
可选的，所述第一辅助气体包括氩气、氦气和氧气中的至少一种。
可选的，所述金属硬掩膜刻蚀方法还包括：
在全部所述刻蚀工艺完成之后，对工艺腔室进行至少一个清洗工艺，每个所述清洗工艺用于去除所述刻蚀工艺在所述工艺腔室内生成的至少一种反应副产物；
其中，所述反应副产物中包括含硅副产物，对所述含硅副产物进行清洗的所述清洗工艺采用的清洗气体包括含氟气体和第二辅助气体，所述第二辅助气体用于减少由所述含氟气体电离形成的等离子体中含氟粒子的生成。
可选的，所述第二辅助气体的流量与所述含氟气体的流量的比值的范围为0.3-2。
可选的，所述第二辅助气体包括氩气、氦气和氧气中的至少一种。
可选的，所述功能膜层为两个，分别为沿远离所述晶圆表面的方向依次设置在所述金属硬掩模层上的介质材料层和有机材料掩膜层；
所述金属硬掩膜刻蚀方法包括：沿靠近所述晶圆表面的方向依次刻蚀所述有机材料掩膜层、所述介质材料层和所述金属硬掩模层的三个刻蚀工艺；
分别对所述有机材料掩膜层和所述介质材料层进行刻蚀的两个刻蚀工艺采用的刻蚀气体均包括氢元素和氟元素。
可选的，所述分别对所述有机材料掩膜层和所述介质材料层进行刻蚀的两个刻蚀工艺采用的刻蚀气体均包括CF 4、CHF 3和CH 2F 2；并且，设定所述CF 4、CHF 3和CH 2F 2的气体流量比例，以使所述CF 4、CHF 3和CH 2F 2中氢元素在所述刻蚀气体中的含量与所述氟元素在所述刻蚀气体中的含量的比值小于所述预设阈值。
本发明实施例具有以下有益效果：
本发明实施例提供的金属硬掩膜刻蚀方法，其在所有的对功能膜层进行刻蚀的刻蚀工艺中，有至少一个刻蚀工艺采用的刻蚀气体包括氢元素和氟元素，且氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值小于预设阈值。通过使氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值小于预设阈值，可以减少氟化氢副产物的生成，从而可以减少因腔室内表面材料(例如Y 2O 3涂层)损耗而产生的颗粒，进而可以有效控制颗粒问题和缺陷问题。
附图说明
图1为本发明实施例提供的金属硬掩膜刻蚀方法的一种流程框图；
图2为本发明实施例提供的金属硬掩膜刻蚀方法的过程图；
图3为本发明实施例提供的金属硬掩膜刻蚀方法的另一种流程框图；
图4为本发明实施例提供的金属硬掩膜刻蚀方法的又一种流程框图；
图5为现有的金属硬掩膜刻蚀方法产生的腔室颗粒与工艺时间的曲线 图；
图6为本发明实施例提供的金属硬掩膜刻蚀方法产生的腔室颗粒与工艺时间的曲线图。
具体实施方式
为使本领域的技术人员更好地理解本发明的技术方案，下面结合附图来对本发明实施例提供的金属硬掩膜刻蚀方法进行详细描述。
本发明实施例提供一种金属硬掩膜刻蚀方法，在晶圆表面沿远离晶圆表面的方向(例如由下而上)依次形成金属硬掩模层和至少一个功能膜层，在实际应用中，不同的技术代对应的功能膜层的数量和种类也不同，例如，在28nm技术代中，功能膜层为两个，分别为沿远离晶圆表面的方向依次设置在金属硬掩模层上的介质材料层和有机材料掩膜层；但是在14nm技术代中，功能膜层至少有三个，例如，在上述介质材料层和有机材料掩膜层的基础上，在介质材料层和有机材料掩膜层之间还设置有无定型碳层或者其他有机材料膜层。另外，在对这些功能膜层进行刻蚀之前，需要在最上层的功能膜层上形成图案化光阻层，用以在对功能膜层进行刻蚀工艺时定义各个功能膜层及金属硬掩模层的图案。
在实际应用中，上述晶圆可以为常规的半导体衬底，例如硅衬底等；或者也可以为包含用于互连线的金属层、层间介质层等的叠层结构；金属硬掩模层例如包括氮化钛(TiN)层；介质材料层例如包括二氧化硅(SiO 2)层和氮化硅(SiN)层；有机材料掩膜层例如包括硅抗反射层(Si-arc层)和底层抗反射层(B-arc层)。本发明实施例对功能膜层的种类没有特别的限制。
请参阅图1，本发明实施例提供的金属硬掩膜刻蚀方法，其包括以下步骤：
S1、沿靠近晶圆表面的方向依次对至少一个功能膜层和金属硬掩膜层进 行刻蚀的多个刻蚀工艺；在所有的对多个功能膜层进行刻蚀的刻蚀工艺中，有至少一个刻蚀工艺采用的刻蚀气体包括氢元素和氟元素。
例如，金属硬掩膜刻蚀方法包括：沿靠近晶圆表面的方向依次刻蚀有机材料掩膜层、介质材料层和金属硬掩模层的三个刻蚀工艺。其中，分别对有机材料掩膜层和介质材料层进行刻蚀的两个刻蚀工艺采用的刻蚀气体均包括CF 4、CHF 3和CH 2F2；对金属硬掩模层进行刻蚀的刻蚀工艺采用的刻蚀气体包括Cl 2、CH 4和BCl 3等。在这种情况下，分别对有机材料掩膜层和介质材料层进行刻蚀的两个刻蚀工艺采用的刻蚀气体均包括氢元素和氟元素。当然，在实际应用中，可以根据具体工艺要求自由选择各个功能膜层的刻蚀工艺所采用的刻蚀气体种类，本发明实施例对此没有特别的限制。
在进行刻蚀工艺的过程中，当刻蚀气体中含有氢元素与氟元素时，会产生氟化氢副产物，其会与腔室内表面材料反应，以腔室内表面材料为Y 2O 3涂层材料为例，氢化氟副产物与Y 2O 3涂层材料反应生成氟化钇(YxFy)，由于氟化钇的分子体积小于Y 2O 3的分子体积，导致Y 2O 3涂层出现浅层裂纹，从而很容易形成含钇成分的颗粒。在长期使用刻蚀设备进行量产的过程中，产生的氢化氟副产物会导致Y 2O 3涂层损耗，甚至会因涂层损坏致使腔室无法继续使用，同时还会形成含钇成分的颗粒，引起颗粒问题以及缺陷问题。
此外，在全部刻蚀工艺完成之后，还需要对腔室进行清洗工艺，以去除反应副产物。请参阅图2，其流程具体包括：首先，将晶圆传入工艺腔室，以进行刻蚀工艺；在完成刻蚀工艺之后，将晶圆传出工艺腔室，然后对工艺腔室进行清洗工艺。
在进行清洗工艺的过程中，清洗气体通常包括氟化氮(NF 3)气体，由该气体产生的等离子体具有极高的腐蚀性，其会进一步深入Y 2O 3涂层产生氟化钇(YxFy)。另外，若清洗气体包括O2，其会与Y 2O 3涂层反应生成YOF，YOF最终会脱落生成颗粒。
为了解决上述问题，对于刻蚀气体包括氢元素和氟元素的刻蚀工艺，通过将氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值控制在小于预设阈值的范围内，可以减少氟化氢副产物的生成，从而可以减少氢化氟副产物与腔室内表面材料反应生成的颗粒(例如氟化钇颗粒)，同时减少室内表面材料(例如Y 2O 3涂层)损耗，进而可以有效控制颗粒问题和缺陷问题。
需要说明的是，上述氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量具体是指工艺腔室中的刻蚀气体所包含的氢元素与氟元素各自的含量。
在一些可选的实施例中，氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值小于或等于1，例如小于或等于0.5。通过将该比值控制在该数值范围内，可以有效减少氟化氢副产物与腔室内表面材料反应生成的颗粒(例如氟化钇颗粒)，同时减少室内表面材料(例如Y 2O 3涂层)损耗。
在一些可选的实施例中，可以通过调节刻蚀气体所包含的各种气体的流量，来调节上述比值。例如，当分别对有机材料掩膜层和介质材料层进行刻蚀的两个刻蚀工艺采用的刻蚀气体均包括CF 4、CHF 3，可以分别将二者的气体流量设定为20sccm和100sccm，在这种情况下，氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值为0.26，小于1，可以有效减少氟化氢副产物与腔室内表面材料反应生成的颗粒。又如，当分别对有机材料掩膜层和介质材料层进行刻蚀的刻蚀工艺采用的刻蚀气体均包括O2、CH 2F 2，可以分别将二者的气体流量设定为80sccm和100sccm，在这种情况下，氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值为1，同样可以有效减少氟化氢副产物与腔室内表面材料反应生成的颗粒。
在一些可选的实施例中，在刻蚀气体包括氢元素和氟元素的刻蚀工艺中，在向工艺腔室通入上述刻蚀气体的同时，向工艺腔室通入第一辅助气体， 该第一辅助气体用于促进刻蚀气体的电离，以进一步减少氟化氢副产物的生成。例如，若刻蚀气体包括CHF 3气体，第一辅助气体可以促进CHF 3气体进一步电离形成CF 2+和CF 3+等自由基和离子，从而可以减少氟化氢副产物的生成。可选的，上述第一辅助气体包括氩气、氦气和氧气中的至少一种。其中，氧气不仅可以促进CHF 3气体进一步电离形成CF 2 +和CF 3 +等自由基和离子，同时还可以与H离子反应生成HO，从而可以进一步减少氟化氢副产物的生成。
在一些可选的实施例中，如图3所示，上述金属硬掩膜刻蚀方法还包括以下步骤：
S2、在全部刻蚀工艺完成之后，对工艺腔室进行至少一个清洗工艺，每个所述清洗工艺用于去除刻蚀工艺在工艺腔室内生成的至少一种反应副产物。
在实际应用中，可以根据在工艺腔室内生成的反应副产物的种类，选择清洗工艺的数量和每个清洗工艺采用的清洗气体的种类。
其中，若反应副产物中包括含硅副产物，则对该含硅副产物进行清洗的清洗工艺采用的清洗气体包括含氟气体和第二辅助气体，其中，含氟气体例如包括NF 3和SF 6等，由含氟气体产生的等离子体具有极高的腐蚀性，其会进一步深入Y 2O 3涂层产生氟化钇(YxFy)。为了解决该问题，可以在通入上述含氟气体的同时，通入上述第二辅助气体，该第二辅助气体用于减少由含氟气体电离形成的等离子体中含氟粒子(例如为氟自由基)的生成，从而可以减少含氟粒子与Y 2O 3涂层反应形成的含钇成分的颗粒。
在一些可选的实施例中，可以通过控制第二辅助气体的流量与含氟气体的流量的比值，来控制由第二辅助气体与含氟气体电离形成的等离子体的成分，以在达到清洗目的的基础上，确保由第二辅助气体电离形成的等离子体能够有效减少由含氟气体电离形成的等离子体中含氟粒子(例如为氟自由基) 的生成。可选的，第二辅助气体的流量与含氟气体的流量的比值的范围为0.3-2。在该数值范围内，可以确保能够有效减少由含氟气体电离形成的等离子体中含氟粒子(例如为氟自由基)的生成。
在一些可选的实施例中，上述第二辅助气体包括氩气、氦气和氧气中的至少一种。
下面以金属硬掩膜刻蚀方法包括：沿靠近晶圆表面的方向依次刻蚀有机材料掩膜层、介质材料层和金属硬掩模层的三个刻蚀工艺以及相对应的清洗工艺为例，对本发明实施例提供的金属硬掩膜刻蚀方法进行详细描述。
具体地，请参阅图4，金属硬掩膜刻蚀方法包括以下步骤：
S101、进行有机材料掩膜层的刻蚀工艺。
有机材料掩膜层的刻蚀工艺例如可以采用下述工艺参数：
刻蚀气体可以采用包含氢元素和氟元素的气体，例如包括CF 4、CHF 3和CH 2F 2；或者，也可以采用不包含氢元素和氟元素的气体，例如包括Cl 2和O 2，或者包括Cl 2、O 2和CH 4。工艺压力的范围为3mT～40mT，优选为5mT～20mT；激励功率的范围为200W～2000W，优选为400W～1200W；偏压功率的范围为20W～500W，优选为60W～200W。若刻蚀气体包括Cl 2和O 2，或者包括Cl 2、O 2和CH 4，则Cl 2的气体流量为50sccm～200sccm，O 2的气体流量为10sccm～35sccm，CH 4的气体流量为0sccm～20sccm。若刻蚀气体包括CF 4、CHF 3和CH 2F 2，则CF 4的气体流量为0sccm～200sccm，CHF 3的气体流量为0sccm～200sccm，CH 2F 2的气体流量为0sccm～200sccm。并且，若刻蚀气体包括CF 4、CHF 3和CH 2F 2，可选的，还可以通入第一辅助气体，例如该第一辅助气体包括Ar、He和O 2中的至少一种，其中，Ar的气体流量为0sccm～200sccm，He的气体流量为0sccm～300sccm，O 2的气体流量为0sccm～150sccm。
在有机材料掩膜层的刻蚀工艺完成之后，会在腔室中形成含碳副产物。
S102、进行介质材料层的刻蚀工艺。
介质材料层的刻蚀工艺例如可以采用下述工艺参数：
刻蚀气体可以采用包含氢元素和氟元素的气体，例如包括CF 4、CHF 3和CH 2F 2；其中，CF 4的气体流量为0sccm～200sccm，CHF 3的气体流量为0sccm～200sccm，CH 2F 2的气体流量为0sccm～200sccm。并且，介质材料层的刻蚀工艺采用的刻蚀气体的总流量与上述有机材料掩膜层的刻蚀工艺采用的刻蚀气体的总流量保持一致；工艺压力的范围为3mT～80mT，优选为5mT～50mT；激励功率的范围为200W～2000W，优选为400W～1600W；偏压功率的范围为20W～500W，优选为60W～400W。
在介质材料层的刻蚀工艺完成之后，会在腔室中形成含硅副产物。
S103、进行金属硬掩模层的刻蚀工艺。
金属硬掩模层的刻蚀工艺例如可以采用下述工艺参数：
刻蚀气体包括Cl 2、CH 4和BCl 3，其中，Cl 2的气体流量为0sccm～200sccm，CH 4的气体流量为0sccm～30sccm，BCl 3的气体流量为0sccm～200sccm；可选的，根据具体工艺的需要，还可以在通入刻蚀气体的同时，通入形貌修饰气体或者实现其他功能的辅助气体(例如能够促进等离子体分散的气体)，形貌修饰气体例如为NF 3和SiCl 4等，NF 3的气体流量为0sccm～200sccm，SiCl 4的气体流量为0sccm～100sccm；其他功能的辅助气体例如为Ar，He和O 2等，Ar的气体流量为0sccm～200sccm，He的气体流量为0sccm～300sccm，O 2的气体流量为0sccm～150sccm。工艺压力的范围为3mT～40mT，优选为5mT～20mT；激励功率的范围为200W～2000W，优选为400W～1200W；偏压功率的范围为20W～300W，优选为60W～200W。
在金属硬掩模层的刻蚀工艺完成之后，会在腔室中形成金属副产物。
在上述步骤1和步骤3两个刻蚀工艺中，若有刻蚀气体包括CF 4、CHF 3和CH 2F 2等的包含氢元素和氟元素的气体，则将该刻蚀气体中氢元素的含量 和氟元素的含量的比值控制在小于预设阈值的范围内，例如该比值的范围为0～1，优选为0～0.5，这样可以减少氟化氢副产物的生成，从而可以减少氟化氢副产物与腔室内表面材料反应生成的颗粒(例如氟化钇颗粒)，同时减少室内表面材料(例如Y 2O 3涂层)损耗，进而可以有效控制颗粒问题和缺陷问题。
进一步的，在上述步骤1和步骤3两个刻蚀工艺中，若有刻蚀气体包括CF 4、CHF 3和CH 2F 2等的包含氢元素和氟元素的气体，还可以在通入上述刻蚀气体的同时，通入第一辅助气体，该第一辅助气体用于促进刻蚀气体的电离，以进一步减少氟化氢副产物的生成。
在采用上述金属硬掩膜刻蚀方法对当前晶圆完成刻蚀工艺之后，针对工艺腔室中形成的多种副产物，即，含碳副产物、含硅副产物和金属副产物，可以在对下一晶圆进行刻蚀工艺之前，采用下述清洗方法对工艺腔室进行清洗，具体包括：
S104、针对金属硬掩膜层的刻蚀工艺产生的金属副产物进行清洗工艺。
具体采用的工艺参数如下：
清洗气体包括Cl 2，其气体流量为0sccm～500sccm；工艺压力的范围为3mT～40mT，优选为5mT～20mT；激励功率的范围为200W～2000W，优选为400W～1200W。
S105、针对介质材料层的刻蚀工艺产生的含硅副产物进行清洗工艺。
具体采用的工艺参数如下：
清洗气体包括NF 3和SF 6，其中，NF 3的气体流量为0sccm～300sccm，SF 6的气体流量为0sccm～100sccm。该清洗气体包括含氟气体，由该含氟气体产生的等离子体具有极高的腐蚀性，其会进一步深入Y 2O 3涂层产生氟化钇(YxFy)。为了解决该问题，可以在通入上述含氟气体的同时，通入第二辅助气体，用于减少由含氟气体电离形成的等离子体中含氟粒子(例如为氟自 由基)的生成，从而可以减少含氟粒子与Y2O3涂层反应形成的含钇成分的颗粒。上述第二辅助气体包括Ar，He和O 2中的至少一种，其中，O 2的气体流量为0sccm～500sccm，Ar的气体流量为0sccm～500sccm，He的气体流量为0sccm～500sccm。进一步的，上述第二辅助气体的流量与含氟气体的流量的比值范围为0.3-2。在该数值范围内，可以确保能够有效减少由含氟气体电离形成的等离子体中含氟粒子(例如为氟自由基)的生成。工艺压力的范围为5mT～250mT，优选为20mT～90mT；激励功率的范围为200W～2000W，优选为800W～1800W。
S106、针对有机材料掩膜层的刻蚀工艺产生的含碳副产物进行清洗工艺。
具体采用的工艺参数如下：
清洗气体包括O 2，其气体流量为0sccm～500sccm；工艺压力的范围为3mT～40mT，优选为5mT～20mT；激励功率的范围为200W～2000W，优选为400W～1200W。
本申请并不限于按照由上述步骤S104至步骤S106的先后顺序进行清洗，上述步骤S104至步骤S106也可以按其他顺序进行，以实现对上述各种副产物的清洗，本申请并不以此设限。
图5为现有的金属硬掩膜刻蚀方法产生的腔室颗粒与工艺时间的曲线图；图6为本发明实施例提供的金属硬掩膜刻蚀方法产生的腔室颗粒与工艺时间的曲线图。如图5和图6所示，PA为工艺腔室内的总颗粒数量；Y 2O 3为工艺腔室内的Y 2O 3的颗粒数量。对比图5和图6可知，现有的金属硬掩膜刻蚀方法，其在工艺腔室内产生的总颗粒数量随着工艺时间的累积逐渐增大至70，而Y 2O 3的颗粒数量随着工艺时间的累积逐渐增大至60。与之相比，本发明实施例提供的金属硬掩膜刻蚀方法，其在工艺腔室内产生的总颗粒数量和Y 2O 3的颗粒数量在不同的工艺时间(0-100h)均控制在10以下，从而 大大减少因腔室内表面材料(例如Y 2O 3涂层)损耗而产生的颗粒，进而可以有效控制颗粒问题和缺陷问题。
本发明实施例提供的金属硬掩膜刻蚀方法，其可以应用于逻辑芯片类产品的制备，例如：中央处理器(CPU)、图形处理器(GPU)和微处理器(MPU)等等。
综上所述，本发明实施例提供的金属硬掩膜刻蚀方法，其在所有的对功能膜层进行刻蚀的刻蚀工艺中，有至少一个刻蚀工艺采用的刻蚀气体包括氢元素和氟元素，且氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值小于预设阈值。通过使氢元素在刻蚀气体中的含量与氟元素在刻蚀气体中的含量的比值小于预设阈值，可以减少氟化氢副产物的生成，从而可以减少因腔室内表面材料(例如Y 2O 3涂层)损耗而产生的颗粒，进而可以有效控制颗粒问题和缺陷问题。
可以理解的是，以上实施方式仅仅是为了说明本发明的原理而采用的示例性实施方式，然而本发明并不局限于此。对于本领域内的普通技术人员而言，在不脱离本发明的精神和实质的情况下，可以做出各种变型和改进，这些变型和改进也视为本发明的保护范围。

Claims (10)

  1. 一种金属硬掩膜刻蚀方法，在晶圆表面上，且沿远离所述晶圆表面的方向依次形成金属硬掩模层和至少一个功能膜层，其特征在于，
    所述金属硬掩膜刻蚀方法包括：沿靠近所述晶圆表面的方向依次对至少一个所述功能膜层和所述金属硬掩膜层进行刻蚀的多个刻蚀工艺；
    在所有的对所述功能膜层进行刻蚀的刻蚀工艺中，有至少一个刻蚀工艺采用的刻蚀气体包括氢元素和氟元素，且所述氢元素在所述刻蚀气体中的含量与所述氟元素在所述刻蚀气体中的含量的比值小于预设阈值，以减少氟化氢副产物的生成。
  2. 根据权利要求1所述的金属硬掩膜刻蚀方法，其特征在于，所述比值小于或等于1。
  3. 根据权利要求2所述的金属硬掩膜刻蚀方法，其特征在于，所述比值小于或等于0.5。
  4. 根据权利要求1所述的金属硬掩膜刻蚀方法，其特征在于，在所述刻蚀气体包括氢元素和氟元素的刻蚀工艺中，在向工艺腔室通入所述刻蚀气体的同时，向所述工艺腔室通入第一辅助气体，所述第一辅助气体用于促进所述刻蚀气体的电离，以减少氟化氢副产物的生成。
  5. 根据权利要求4所述的金属硬掩膜刻蚀方法，其特征在于，所述第一辅助气体包括氩气、氦气和氧气中的至少一种。
  6. 根据权利要求1所述的金属硬掩膜刻蚀方法，其特征在于，所述金属硬掩膜刻蚀方法还包括：
    在全部所述刻蚀工艺完成之后，对工艺腔室进行至少一个清洗工艺，每个所述清洗工艺用于去除所述刻蚀工艺在所述工艺腔室内生成的至少一种反应副产物；
    其中，所述反应副产物中包括含硅副产物，对所述含硅副产物进行清洗的所述清洗工艺采用的清洗气体包括含氟气体和第二辅助气体，所述第二辅助气体用于减少由所述含氟气体电离形成的等离子体中含氟粒子的生成。
  7. 根据权利要求6所述的金属硬掩膜刻蚀方法，其特征在于，所述第二辅助气体的流量与所述含氟气体的流量的比值的范围为0.3-2。
  8. 根据权利要求6所述的金属硬掩膜刻蚀方法，其特征在于，所述第二辅助气体包括氩气、氦气和氧气中的至少一种。
  9. 根据权利要求1-8任意一项所述的金属硬掩膜刻蚀方法，其特征在于，所述功能膜层为两个，分别为沿远离所述晶圆表面的方向依次设置在所述金属硬掩模层上的介质材料层和有机材料掩膜层；
    所述金属硬掩膜刻蚀方法包括：沿靠近所述晶圆表面的方向依次刻蚀所述有机材料掩膜层、所述介质材料层和所述金属硬掩模层的三个刻蚀工艺；
    分别对所述有机材料掩膜层和所述介质材料层进行刻蚀的两个刻蚀工艺采用的刻蚀气体均包括氢元素和氟元素。
  10. 根据权利要求9所述的金属硬掩膜刻蚀方法，其特征在于，所述分别对所述有机材料掩膜层和所述介质材料层进行刻蚀的两个刻蚀工艺采用的刻蚀气体均包括CF 4、CHF 3和CH 2F 2；并且，设定所述CF 4、CHF 3和CH 2F 2的气体流量比例，以使所述CF 4、CHF 3和CH 2F 2中氢元素在所述刻蚀气体中的含量与所述氟元素在所述刻蚀气体中的含量的比值小于所述预设阈值。
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