WO2021200240A1 - Etching method and etching device - Google Patents

Etching method and etching device Download PDF

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Publication number
WO2021200240A1
WO2021200240A1 PCT/JP2021/011215 JP2021011215W WO2021200240A1 WO 2021200240 A1 WO2021200240 A1 WO 2021200240A1 JP 2021011215 W JP2021011215 W JP 2021011215W WO 2021200240 A1 WO2021200240 A1 WO 2021200240A1
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Prior art keywords
film
gas
etching
amine
substrate
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PCT/JP2021/011215
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French (fr)
Japanese (ja)
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信博 高橋
折居　武彦
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東京エレクトロン株式会社
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Publication of WO2021200240A1 publication Critical patent/WO2021200240A1/en

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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
    • 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

Definitions

  • This disclosure relates to an etching method and an etching apparatus.
  • a Si (silicon) film formed on a semiconductor wafer (hereinafter referred to as a wafer) as a substrate may be etched.
  • a Si film is selectively etched with respect to a SiGe (silicon germanium) film by using F 2 (fluorine) gas and NH 3 gas.
  • the present disclosure provides a technique capable of rapidly etching a silicon film formed on a substrate.
  • the etching method of the present disclosure includes a step of supplying fluorine gas and amine gas to a substrate having a silicon film formed on the surface to etch the silicon film.
  • the silicon film formed on the substrate can be quickly etched.
  • FIG. 1 shows a longitudinal side view of the surface portion of the wafer W on which the processing is performed.
  • 11 is a SiGe (silicon germanium) film
  • a silicon oxide (SiOx) film 12 is laminated on the upper side of the SiGe film 11.
  • a recess 13 is formed in the laminate of the silicon oxide film 12 and the SiGe film 11, and the polysilicon film 14 is embedded in the recess 13.
  • the SiOCN film 15, that is, silicon which surrounds the side of the polysilicon film 14 and is in contact with the side wall of the polysilicon film 14 and the side wall of the recess 13, respectively.
  • a membrane composed of oxygen, nitrogen and carbon is provided. Therefore, the polysilicon film 14, the first film SiOCN film 15, and the second film SiGe film 11 are formed so as to be adjacent to each other in this order when viewed in the lateral direction.
  • the SiOCN film 15 is an interlayer insulating film called a low-k film, and is a porous film. Therefore, the holes of the SiOCN film 15 are open in the polysilicon film 14 and the SiGe film 11.
  • the polysilicon film 14 is a film to be etched, and the SiGe film 11 is a non-etched film.
  • the silicon oxide film 12 is an etching mask film when etching the polysilicon film 14.
  • F 2 gas and amine gas are supplied to the wafer W. As shown in the evaluation test described later, the etching rate of the polysilicon film can be increased by supplying the F 2 gas and the amine gas.
  • the F 2 gas which is an etching gas for the polysilicon film 14 also has an etching property for the SiGe film 11. That is, the polysilicon film 14 and the SiGe film 11 have an etching property with respect to the F 2 gas. It is assumed that the polysilicon film 14 is etched without supplying amine gas. In that case, in the process of etching the polysilicon film 14, the etching gas (F 2 gas) passes through the pores of the SiOCN film 15 and is supplied to the side wall of the SiGe film 11, and the side wall is etched. It ends up. The amine gas enters the pores of the SiOCN film 15 and is adsorbed on the pore walls to prevent the passage of F 2 gas in the pores. As a result, it has a role of preventing the supply of F 2 gas to the side wall of the SiGe film 11 and preventing etching of the side wall.
  • amine has low adsorptivity to the polysilicon film 14, while has high adsorptivity to the SiOCN film 15 and the silicon oxide film 12 which are oxygen-containing silicon films. Therefore, by supplying the amine gas, the surfaces of the SiOCN film 15 and the silicon oxide film 12 are each coated with a protective film of amine, and contact with the etching gas is prevented. Therefore, this protective film prevents etching of the SiOCN film 15 and the silicon oxide film 12. On the other hand, since it is difficult for a protective film to be formed on the surface of the polysilicon film 14, the polysilicon film 14 is etched.
  • the polysilicon film 14 SiOCN film 15, and silicon oxide film 12 exposed on the surface of the wafer W, only the polysilicon film 14 is selectively etched. Since amine has such high adsorptivity to the SiOCN film 15, the performance of preventing the passage of F 2 gas by adsorbing the SiOCN film 15 to the pore wall is high.
  • FIGS. 2 to 5 are schematic views showing how the surface portion of the wafer W described with reference to FIG. 1 changes depending on the processing.
  • the wafer W is carried into the processing container. This is performed in a state where the inside of the processing container is exhausted to create a vacuum atmosphere at a predetermined pressure.
  • 16 is a hole formed in the SiOCN film 15.
  • the amine to be supplied to the wafer W as 21, the amine 21, in this embodiment, for example butylamine (C 4 H 11 N). Further, F 2 gas is shown as 22.
  • the protective film formed on the surfaces of the SiOCN film 15 and the silicon oxide film 12 by the amine 21 is shown as 23.
  • amine gas (amine 21 in a gas state) is supplied as amine 21 into the processing container (step S1, FIG. 2A, FIG. 2B).
  • amine gas amine 21 in a gas state
  • a relatively large amount of amine 21 is adsorbed and stays on the pore wall forming the pore 16, and the pore 16 is sealed.
  • a protective film 23 composed of the amine 21 is formed on the upper surfaces of the SiOCN film 15 and the silicon oxide film 12. ..
  • the supply of the amine gas into the processing container is stopped, and the exhaust gas and, for example , the purge gas, which is N 2 (nitrogen) gas, are supplied in the processing container (step S2, FIG. 2C).
  • the purge gas which is N 2 (nitrogen) gas
  • the F 2 gas 22 is supplied into the processing container, the polysilicon film 14 is etched, and the side wall on the upper side of the SiOCN film 15 is exposed (step S3, FIG. 3A).
  • the amine 21 remains in the pores 16 on the upper side of the SiOCN film 15, and the amine 21 prevents the F 2 gas 22 from passing through the pores 16 and reaching the SiGe film 11. Will be done.
  • the protective film 23 is coated, the upper surfaces of the SiOCN film 15 and the silicon oxide film 12 are prevented from being etched by the F 2 gas 22. Therefore, among the silicon oxide film 12, the SiOCN film 15, and the polysilicon film 14, the polysilicon film 14 is selectively etched.
  • the F 2 gas 22 is activated by the amine 21 adsorbed on the surface of the wafer W, and the polysilicon film 14 is etched at a relatively high etching rate as described above.
  • step S4 the supply of the F 2 gas 22 into the processing container is stopped, the exhaust gas and the purge gas are supplied in the processing container (step S4, FIG. 3B), and the F 2 gas remaining in the processing container is reached. 22 is removed by riding on the airflow of the purge gas exhausted from the processing container. Subsequently, amine gas is supplied into the processing container. That is, step S1 is executed again.
  • step S3 the polysilicon film 14 is etched to expose the upper side wall of the SiOCN film 15. Therefore, the amine 21 supplied in the second step S1 is supplied to the pore 16 below the pore 16 to which the amine 21 was supplied in the first step S1 in the SiOCN film 15, and is supplied to the pore wall. It is adsorbed (Fig. 4A).
  • a protective film 23 is also formed on the side wall of the exposed SiOCN film 15.
  • the exhaust gas and the purge gas in the processing container of step S2 are supplied again.
  • the F 2 gas 22 is supplied into the processing container in step S3, the polysilicon film 14 is further etched downward, and the exposed region on the side wall of the SiOCN film 15 expands downward. .. Also at this time, the polysilicon film 14 is etched at a high etching rate by the F 2 gas 22 activated by the amine 21 adsorbed on the surface of the wafer W.
  • the region where the amine 21 is supplied in the SiOCN film 15 is expanded downward, so that the vicinity of the side wall of the SiOCN film 15 newly exposed by etching the polysilicon film 14
  • the amine 21 remains in the pore 16 of the. Therefore, also in this second step S3, it is possible to prevent the etching gas from passing through the pores 16 of the SiOCN film 15 and etching the side wall of the SiGe film 11.
  • the protective film 23 formed on the upper surface of each of the SiOCN film 15 and the silicon oxide film 12 and the side surface of the SiOCN film prevents etching of the SiOCN film 15 and the silicon oxide film (FIG. 4B). After this etching, the exhaust gas and purge gas supply in step S4 are performed again.
  • steps S1 to S4 performed in this order are one cycle
  • the cycle is repeated even after the second step S4 is performed, for example.
  • the polysilicon film 14 is etched downward while the SiOCN film 15, the SiGe film 11 and the silicon oxide film 12 are prevented from being etched.
  • step S5 the wafer W is heated.
  • the amine 21 that has entered the pore 16 and the amine 21 that forms the protective film 23 are vaporized and removed from the wafer W (FIG. 5B).
  • the amine 21 stays on the wafer W surface during etching in the above series of treatments, it reacts with the F 2 gas 22 to become a reaction product and stays on the wafer W surface. It is also possible that it may remain as a reaction product as such. Then, when such a reaction product is generated, heating is performed so that the reaction product is removed in step S5. That is, the heating in step S5 is heating for removing the amine 21 and / or the reaction product, and specifically, the wafer W is heated to, for example, 100 ° C. to 400 ° C.
  • FIG. 6 shows the surface portion of the wafer W after the execution of step S5. In the recess 17 formed by removing the polysilicon film 14, for example, a gate of a semiconductor device is formed in a later step. NS.
  • the polysilicon film 14 is etched at a relatively high etching rate, the time required for repeating steps S1 to S4 can be shortened. Therefore, the production efficiency of the semiconductor device can be increased.
  • the pores 16 of the SiOCN film 15 are sealed by the amine 21, and the protective film 23 made of the amine 21 is formed so as to cover the silicon oxide film 12, so that the silicon oxide film 12 is formed. Etching is prevented. Therefore, etching from the side and etching from above are prevented for the SiGe film 11 located on the side of the SiOCN film 15 and below the silicon oxide film 12. Therefore, it is possible to suppress a decrease in the yield of the semiconductor device.
  • F 2 gas and NH 3 gas can be used for etching the polysilicon film as described in Patent Document 1.
  • the amine gas for preventing the etching gas from passing through the pores 16 is used for etching, and the NH 3 gas may not be supplied to the wafer W. That is, in the treatment of the above embodiment, NH is compared with the case where the amine gas is supplied for the protection of the SiGe film 11 and the etching gas and the NH 3 gas are supplied for the etching of the polysilicon film 14. 3 Gas supply is no longer required. Therefore, it is not necessary to provide an NH 3 gas supply system for the device that performs the series of processes shown in FIGS. 2 to 5 above. That is, according to the treatment of the above embodiment, it is possible to prevent an increase in the types of gas required for the treatment and suppress an increase in the manufacturing cost and the operating cost of the treatment apparatus.
  • the exhaust flow rate of the processing container may be constant in steps S1 to S4 described above, and the exhaust flow rate in steps S2 and S4 for removing unnecessary gas in the processing container is more reliably removed. It may be larger than the exhaust flow rate of steps S1 and S3 so as to be able to do so. Further, in steps S2 and S4, unnecessary gas may be removed only by exhaust gas without supplying purge gas.
  • an example is a film structure of the wafer W shown in FIG. 1, as the Si film is etched by the supply of F 2 gas and amine gas is not limited to the polysilicon film 14 may be, for example, amorphous silicon film .
  • the non-etching film is the SiGe film 11, but it may be, for example, a Si film. Further, the non-etching film may be a film other than the silicon-containing film such as these Si film and SiGe film 11. Further, the mask film provided on the SiGe film 11 is not limited to the silicon oxide film 12 as long as it can suppress the etching of the SiGe film 11 from the upper side at the time of etching.
  • the upper side of the SiGe film 11 may be covered with the SiOCN film 15. That is, the SiOCN film 15 is provided from the side to the upper side of the SiGe film 11. In that case, when the etching gas is supplied to the wafer W, the amine gas is adsorbed on the SiOCN film 15 covering the upper side of the SiGe film 11, so that the etching gas comes into contact with the SiGe film 11 from the upper side of the SiGe film 11. Is prevented.
  • the porous film is not limited to the SiOCN film 15, and a porous film such as a SiCO film or a SiCOH film may be formed instead of the SiOCN film 15.
  • amines are easily adsorbed on the oxygen-containing silicon membrane, so that the porous membrane preferably contains oxygen in order to adsorb the amine.
  • the term "containing oxygen” as used herein does not mean that oxygen is contained as an impurity, but means that oxygen is contained as a component constituting the film.
  • steps S1 to S4 are shown to be repeated three or more times, but the number of repetitions is not limited to the above example, and may be, for example, two times. Further, steps S1 to S4 may be performed only once without repeating. By the way, the above steps S2 and S4 for removing unnecessary gas may be omitted.
  • FIG. 7A which shows the timing of supplying the amine gas and the F 2 gas into the processing container, respectively, the other of the amine gas and the F 2 gas is not spaced from the end of the supply. Gas may be supplied. May so omit steps S2, S4, amine gas, for F 2 gas step for supplying respectively S1, S3, not limited to be repeated, may be performed only once.
  • the amine gas and the F 2 gas 22 are not limited to being supplied in order. That is, of the amine gas and F 2 gas 22 is not limited to starting the supply of one gas the other gas after completion of the supply of, as shown in FIG. 7B, at the same time the wafer W the amine gas and F 2 gas 22 It may be supplied and processed.
  • the amine gas and the F 2 gas 22 are supplied at the same time in this way, the polysilicon film 14 is etched by the F 2 gas 22 while sealing the pores 16 with the amine gas and forming the protective film 23.
  • step S5 the wafer W is heated so that the reaction product of the amine 21 and / or the amine 21 and the F 2 gas is removed from the SiOCN film 15.
  • the amine 21 and / or the reaction product may remain as long as the dielectric constant of the SiOCN film 15 is not practically problematic. Can be considered. Therefore, the heat treatment in step S5 is not always essential.
  • the amine 21 constituting the amine gas is not limited to butylamine. Specific examples include hexylamine, dipropylamine, n-octylamine, tertbutylamine, decylamine, dodecylamine, dicyclohexylamine, tetradecylamine and the like.
  • the boiling point of each amine thus exemplified is contained in the range of 100 ° C. to 400 ° C. Therefore, in order to remove the amine as a vaporized state in step S5 of the above embodiment, it is preferable to heat the wafer W to 100 ° C. to 400 ° C. in this way.
  • the substrate processing device 3 is adjacent to the loading / unloading section 31 for loading / unloading the wafer W, the two load lock chambers 41 provided adjacent to the loading / unloading section 31, and the two load lock chambers 41, respectively. It includes two heat treatment modules 40 provided and two etching modules 5 provided adjacent to each of the two heat treatment modules 40.
  • the carry-in / out section 31 is provided with a first substrate transport mechanism 32 and a normal pressure transport chamber 33 having a normal pressure atmosphere, and a carrier provided on the side of the normal pressure transport chamber 33 for accommodating the wafer W. It is provided with a carrier mounting table 35 on which the 34 is mounted. Reference numeral 36 denotes an orientation chamber adjacent to the normal pressure transfer chamber 33, which is provided to rotate the wafer W to optically determine the amount of eccentricity and align the wafer W with respect to the first substrate transfer mechanism 32. ..
  • the first substrate transport mechanism 32 transports the wafer W between the carrier 34 on the carrier mounting table 35, the oriental chamber 36, and the load lock chamber 41.
  • each load lock chamber 41 for example, a second substrate transfer mechanism 42 having an articulated arm structure is provided, and the second substrate transfer mechanism 42 uses the wafer W as the load lock chamber 41 and the heat treatment module 40. And the etching module 5.
  • the inside of the processing container constituting the heat treatment module 40 and the inside of the processing container forming the etching module 5 have a vacuum atmosphere, and the inside of the load lock chamber 41 includes the inside of the processing container having such a vacuum atmosphere and the normal pressure transfer chamber 33. The normal pressure atmosphere and the vacuum atmosphere are switched so that the wafer W can be transferred between the two.
  • 43 is a gate valve that can be opened and closed, and is between the normal pressure transfer chamber 33 and the load lock chamber 41, between the load lock chamber 41 and the heat treatment module 40, and between the heat treatment module 40 and the etching module 5, respectively. It is provided.
  • the heat treatment module 40 the above-mentioned processing container, an exhaust mechanism for exhausting the inside of the processing container to form a vacuum atmosphere, a mounting table provided in the processing container and capable of heating the mounted wafer W, and the like are provided. Including, it is configured so that the above-mentioned step S5 can be executed.
  • the etching module 5 is a module that performs the processing of steps S1 to S4 on the wafer W, and includes, for example, a circular processing container 51. That is, the processes of steps S1 to S4 are performed in the same processing container.
  • the processing container 51 is an airtight vacuum container, and a circular mounting table (stage) 61 on which the wafer W is placed on a horizontally formed surface (upper surface) is provided on the lower side of the processing container 51. ing.
  • reference numeral 62 denotes a stage heater embedded in the mounting table 61, which heats the wafer W to a predetermined temperature so that the above steps S1 to S4 can be performed.
  • Reference numeral 63 denotes a support column that supports the mounting table 61, which is a mounting portion, on the bottom surface of the processing container 51.
  • 64 is a vertical elevating pin, and the surface of the mounting table 61 is recessed by the elevating mechanism 65, and the wafer W is transferred between the second substrate transport mechanism 42 and the mounting table 61 described above.
  • Three lifting pins 64 are provided, but only two are shown.
  • reference numeral 66 denotes a side wall heater provided on the side wall of the processing container 51, which adjusts the temperature of the atmosphere inside the processing container 51.
  • the side wall of the processing container 51 is provided with a transfer port for the wafer W which can be opened and closed (not shown).
  • 67 is an exhaust port opened on the bottom surface of the processing container 51, and is connected to an exhaust mechanism 68 composed of a vacuum pump, a valve, and the like via an exhaust pipe. By adjusting the exhaust flow rate from the exhaust port 67 by the exhaust mechanism 68, the pressure in the processing container 51 is adjusted.
  • the gas shower head 7 constituting a gas supply unit is provided so as to face the mounting table 61.
  • the gas shower head 7 includes a shower plate 71, a gas diffusion space 72, and a diffusion plate 73.
  • the shower plate 71 is horizontally provided so as to form a lower surface portion of the gas shower head 7, and a large number of gas discharge holes 74 are dispersed and formed in order to discharge gas into the mounting table 61 in a shower shape.
  • the gas diffusion space 72 is a flat space formed so that the lower side thereof is partitioned by the shower plate 71 in order to supply gas to each gas discharge hole 74.
  • a diffusion plate 73 is horizontally provided so as to divide the gas diffusion space 72 into upper and lower parts.
  • Reference numeral 75 in the figure is a through hole formed in the diffusion plate 73, and a large number of through holes are dispersed and perforated in the diffusion plate 73.
  • Reference numeral 77 in the figure is a ceiling heater, which adjusts the temperature of the gas shower head 7.
  • the downstream ends of the gas supply pipes 78 and 81 are connected to the upper side of the gas diffusion space 72.
  • the upstream side of the gas supply pipe 78 is connected to the F 2 gas supply source 70 via the flow rate adjusting unit 79.
  • the flow rate adjusting unit 79 is composed of a valve and a mass flow controller, and adjusts the flow rate of the gas supplied to the downstream side of the gas supply pipe 78.
  • Each flow rate adjusting unit which will be described later, has the same configuration as the flow rate adjusting unit 79, and adjusts the flow rate of the gas supplied to the downstream side of the pipe through which the flow rate adjusting unit is provided.
  • the upstream side of the gas supply pipe 81 is connected to the tank 83 in which the liquid amine is stored via the flow rate adjusting unit 82.
  • the tank 83 is provided with a heater that heats and vaporizes the amine inside, and is configured to be able to supply the vaporized amine (amine gas) to the downstream side of the gas supply pipe 81.
  • the gas supply pipe 81 branches on the upstream side of the flow rate adjusting unit 82 to form the gas supply pipe 84.
  • the gas supply pipe 84 is connected to the N 2 (nitrogen) supply source 86 via the flow rate adjusting unit 85. Therefore, the amine gas and the N 2 gas can be independently supplied to the gas shower head 7.
  • 52 is a heater provided in the gas supply pipe 81.
  • step S1 amine gas is supplied to the gas shower head 7 from the tank 83 described above, and is supplied into the processing container 51.
  • step S2 S4, N 2 gas from the N 2 gas supply source 86 is supplied to the gas shower head 7, is supplied as a purge gas into the processing vessel 51.
  • step S3 the supply of gas from the tank 83 and the N 2 gas supply source 86 is stopped, the F 2 gas is supplied from the supply source 70 to the gas shower head 7, and is supplied into the processing container 51.
  • the temperature of the wafer W is set to, for example, 0 ° C. to 150 ° C.
  • the pressure in the processing container 51 during processing is, for example, 13.3 Pa (100 mTorr) to 666.5 Pa (5000 mTorr).
  • the flow rate of the F 2 gas supplied into the processing container 51 is, for example, 100 sccm to 2000 sccm, and the flow rate of the amine gas such as butylamine supplied into the processing container 51 is, for example, 1 sccm to 500 sccm.
  • the substrate processing device 3 includes a control unit 30 which is a computer, and the control unit 30 includes a program, a memory, and a CPU.
  • the program incorporates instructions (each step) for processing the wafer W and transporting the wafer W as described above, and the program includes computer storage media such as a compact disk, a hard disk, and a magneto-optical disk. It is stored in a DVD or the like and installed in the control unit 30.
  • the control unit 30 outputs a control signal to each unit of the substrate processing device 3 by the program, and controls the operation of each unit.
  • the operation of the etching module 5, the operation of the heat treatment module 40, the operation of the first substrate transfer mechanism 32, the operation of the second substrate transfer mechanism 42, and the operation of the oriental chamber 36 are controlled by control signals.
  • the operations of the etching module 5 include adjusting the output of each heater, supplying and stopping each gas from the gas shower head 7, adjusting the exhaust flow rate by the exhaust mechanism 68, and raising and lowering the lifting pin 64 by the lifting mechanism 65.
  • the operation is included.
  • An etching apparatus is configured by the control unit 30 and the etching module 5.
  • a carrier 34 containing a wafer W on which each film is formed is placed on a carrier mounting table 35. Then, the wafer W is conveyed in the order of the normal pressure transfer chamber 33 ⁇ the oriental chamber 36 ⁇ the normal pressure transfer chamber 33 ⁇ the load lock chamber 41, and is conveyed to the etching module 5 via the heat treatment module 40. Then, as described above, the cycle consisting of steps S1 to S4 is repeatedly performed to process the wafer W. Subsequently, the wafer W is conveyed to the heat treatment module 40 and undergoes the process of step S5. After that, the wafer W is conveyed in the order of the load lock chamber 41 ⁇ the normal pressure transport chamber 33, and is returned to the carrier 34.
  • the transport mechanism may be configured to be transported. However, by supplying these gases in the same processing container, it is possible to save the time for transporting the wafer W between the modules in repeating the above cycle. Therefore, according to the configuration of the substrate processing device 3, the throughput can be improved.
  • Evaluation test An evaluation test conducted in connection with the technique of the present disclosure will be described.
  • ⁇ Evaluation test 1 As evaluation test 1, etching was performed by supplying butylamine gas together with F 2 gas to the Si film on the substrate. After this treatment, the etching amount of the Si film (thickness of the etched film) and the roughness of the surface of the remaining Si film were measured. The temperature of the substrate at the time of etching, the pressure in the processing container for storing the substrate, the flow rate of F 2 gas into the processing container, and the flow rate of butylamine gas into the processing container are described in the embodiments. Processing was performed by setting the value in the range.
  • etching was performed in the same manner as in the evaluation test 1 except that NH 3 gas was supplied instead of the butylamine gas, and the etching amount of the Si film and the roughness of the surface of the Si film were measured.
  • the graph of FIG. 10 shows the results of the evaluation test 1 and the comparative test 1.
  • the etching amount is 65.0 nm in the evaluation test 1 and 46.0 nm in the comparative test 1, and the evaluation test 1 is larger. Therefore, by supplying the F 2 gas and the NH 3 gas as described in the embodiment, the etching amount per unit time can be increased.
  • the evaluation test 1 has a roughness of 5.8 nm and the comparative test 1 has a roughness of 12.6 nm, and the evaluation test 1 is smaller. That is, in the evaluation test 1, the roughness of the Si film after etching is suppressed.
  • this technique can also be applied to a process of etching only a part of the Si film. In that case, it is advantageous because it is possible to suppress the occurrence of defects due to the influence of the unevenness on the surface of the Si film for each treatment performed after the etching of the Si film.
  • FIG. 11 is a bar graph showing the results of this evaluation test 2.
  • the vertical axis of the graph shows the adsorption energy (unit: eV), and the lower the adsorption energy, the easier it is to adsorb.
  • eV adsorption energy
  • NH 3 , butylamine, hexylamine and trimethylamine are all easily adsorbed on SiO 2 CN and SiO. This is because the adsorption sites of amines and ammonia are O atoms.
  • the difference in the adsorptivity of amines between the Si film, the silicon oxide film and the SiOCN film is utilized to protect the silicon oxide film and the SiOCN film as described in the embodiment, while Si. It can be estimated that selective etching of the film is possible. Further, it can be estimated that the pores can be sealed by adsorbing amines on the pore walls of the SiOCN film.
  • Evaluation test 3 As evaluation test 3, butylamine gas was supplied to a substrate having different types of films on each surface. Then, the amount of butylamine adsorbed on each film was measured by a gas chromatograph mass spectrometer (GC-MS).
  • GC-MS gas chromatograph mass spectrometer
  • FIG. 12 shows the result of this evaluation test 3.
  • the adsorption amount of the polysilicon (Poly-Si) film and the amorphous silicon ( ⁇ -Si) film is approximately 0 ng / cm 2 .
  • the adsorption amount on the silicon oxide film is approximately 0.10 ng / cm 2
  • the adsorption amount on the SiOCN film is approximately 0.27 ng / cm 2 . Therefore, it was shown that the adsorbability of amine is larger in the Si film (silicon oxide film and SiOCN) containing oxygen than in the Si film (polysilicon film and amorphous silicon film). Therefore, from the result of the evaluation test 3, as in the result of the evaluation test 2, it is possible to selectively etch the Si film as shown in the embodiment by utilizing the difference in the adsorptivity of amines. Presumed.

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Abstract

According to the present invention, a silicon film that is formed on the surface of a substrate is etched by supplying a fluorine gas and an amine gas to the substrate.

Description

エッチング方法及びエッチング装置Etching method and etching equipment
　本開示は、エッチング方法及びエッチング装置に関する。 This disclosure relates to an etching method and an etching apparatus.
　半導体装置を構成するにあたり、基板である半導体ウエハ（以下、ウエハと記載する）に形成されたＳｉ（シリコン）膜のエッチングが行われる場合が有る。例えば特許文献１にはＦ２（フッ素）ガス及びＮＨ３ガスを用いて、Ｓｉ膜をＳｉＧｅ（シリコンゲルマニウム）膜に対して選択的にエッチングすることが示されている。 In constructing a semiconductor device, a Si (silicon) film formed on a semiconductor wafer (hereinafter referred to as a wafer) as a substrate may be etched. For example, Patent Document 1 discloses that a Si film is selectively etched with respect to a SiGe (silicon germanium) film by using F 2 (fluorine) gas and NH 3 gas.
特開２０１６－１４３７８１号公報Japanese Unexamined Patent Publication No. 2016-143781
　本開示は、基板に形成されたシリコン膜を速やかにエッチングすることができる技術を提供する。 The present disclosure provides a technique capable of rapidly etching a silicon film formed on a substrate.
　本開示のエッチング方法は、表面にシリコン膜が形成された基板にフッ素ガスとアミンガスとを供給して、当該シリコン膜をエッチングする工程を含む。 The etching method of the present disclosure includes a step of supplying fluorine gas and amine gas to a substrate having a silicon film formed on the surface to etch the silicon film.
　本開示は、基板に形成されたシリコン膜を速やかにエッチングすることができる。 According to the present disclosure, the silicon film formed on the substrate can be quickly etched.
本開示の一実施形態に係るエッチングが行われるウエハの表面の縦断側面図である。It is a longitudinal side view of the surface of the wafer where the etching which concerns on one Embodiment of this disclosure is performed. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. 前記エッチングを説明する工程図である。It is a process drawing explaining the etching. エッチング処理後のウエハの表面の縦断側面図である。It is a longitudinal side view of the surface of the wafer after etching treatment. エッチング時のガスの供給タイミングの一例を示すチャート図である。It is a chart figure which shows an example of the gas supply timing at the time of etching. エッチング時のガスの供給タイミングの一例を示すチャート図である。It is a chart figure which shows an example of the gas supply timing at the time of etching. エッチングを行うための基板処理装置の平面図である。It is a top view of the substrate processing apparatus for performing etching. 前記基板処理装置に設けられるエッチングモジュールの縦断側面図である。It is a longitudinal side view of the etching module provided in the substrate processing apparatus. 評価試験の結果を示すグラフ図である。It is a graph which shows the result of the evaluation test. 評価試験の結果を示すグラフ図である。It is a graph which shows the result of the evaluation test. 評価試験の結果を示すグラフ図である。It is a graph which shows the result of the evaluation test.
　本開示のエッチング方法の一実施形態に係る処理を以下に説明する。図１は、その処理が行われるウエハＷの表面部の縦断側面図を示している。図中１１はＳｉＧｅ（シリコンゲルマニウム）膜であり、ＳｉＧｅ膜１１の上側には酸化シリコン（ＳｉＯｘ）膜１２が積層されている。この酸化シリコン膜１２とＳｉＧｅ膜１１との積層体には、凹部１３が形成されており、この凹部１３内にはポリシリコン膜１４が埋め込まれている。また、ポリシリコン膜１４の側壁と凹部１３の側壁との間には、ポリシリコン膜１４の側方を囲み、ポリシリコン膜１４の側壁及び凹部１３の側壁に各々接するＳｉＯＣＮ膜１５、即ちシリコン、酸素、窒素及び炭素により構成される膜が設けられている。従って、横方向に見てポリシリコン膜１４、第１の膜であるＳｉＯＣＮ膜１５、第２の膜であるＳｉＧｅ膜１１が、この順に隣り合うように形成されている。 The process according to one embodiment of the etching method of the present disclosure will be described below. FIG. 1 shows a longitudinal side view of the surface portion of the wafer W on which the processing is performed. In the figure, 11 is a SiGe (silicon germanium) film, and a silicon oxide (SiOx) film 12 is laminated on the upper side of the SiGe film 11. A recess 13 is formed in the laminate of the silicon oxide film 12 and the SiGe film 11, and the polysilicon film 14 is embedded in the recess 13. Further, between the side wall of the polysilicon film 14 and the side wall of the recess 13, the SiOCN film 15, that is, silicon, which surrounds the side of the polysilicon film 14 and is in contact with the side wall of the polysilicon film 14 and the side wall of the recess 13, respectively. A membrane composed of oxygen, nitrogen and carbon is provided. Therefore, the polysilicon film 14, the first film SiOCN film 15, and the second film SiGe film 11 are formed so as to be adjacent to each other in this order when viewed in the lateral direction.
ＳｉＯＣＮ膜１５はlow-ｋ膜と呼ばれる層間絶縁膜であり、多孔質膜である。従って、ポリシリコン膜１４及びＳｉＧｅ膜１１に、ＳｉＯＣＮ膜１５の孔部が開口している。ポリシリコン膜１４は被エッチング膜であり、ＳｉＧｅ膜１１は非エッチング膜である。酸化シリコン膜１２は、ポリシリコン膜１４をエッチングする際におけるエッチングマスク膜である。この実施形態の概略を説明しておくと、ポリシリコン膜１４をエッチングするにあたり、ウエハＷに対してＦ２ガスとアミンガスとの供給を行う。後述の評価試験から示されるように、Ｆ２ガスとアミンガスとを供給することで、ポリシリコン膜についてのエッチングレートを高くすることができる。 The SiOCN film 15 is an interlayer insulating film called a low-k film, and is a porous film. Therefore, the holes of the SiOCN film 15 are open in the polysilicon film 14 and the SiGe film 11. The polysilicon film 14 is a film to be etched, and the SiGe film 11 is a non-etched film. The silicon oxide film 12 is an etching mask film when etching the polysilicon film 14. To explain the outline of this embodiment, when etching the polysilicon film 14, F 2 gas and amine gas are supplied to the wafer W. As shown in the evaluation test described later, the etching rate of the polysilicon film can be increased by supplying the F 2 gas and the amine gas.
ところで、ポリシリコン膜１４に対するエッチングガスであるＦ２ガスは、ＳｉＧｅ膜１１に対してもエッチング性を有している。つまり、Ｆ２ガスに対してポリシリコン膜１４及びＳｉＧｅ膜１１は被エッチング性を有している。仮に、アミンガスを供給せずにポリシリコン膜１４のエッチングを行うとする。その場合、ポリシリコン膜１４のエッチングが進行する過程で、エッチングガス（Ｆ２ガス）がＳｉＯＣＮ膜１５の孔部を通過してＳｉＧｅ膜１１の側壁に供給されてしまい、当該側壁がエッチングされてしまう。上記のアミンガスは、ＳｉＯＣＮ膜１５の孔部に進入して孔壁に吸着することで、当該孔部におけるＦ２ガスの通過を防止する。それによりＳｉＧｅ膜１１の側壁へのＦ２ガスの供給を防ぎ、当該側壁のエッチングを防ぐ役割を有する。 By the way, the F 2 gas, which is an etching gas for the polysilicon film 14, also has an etching property for the SiGe film 11. That is, the polysilicon film 14 and the SiGe film 11 have an etching property with respect to the F 2 gas. It is assumed that the polysilicon film 14 is etched without supplying amine gas. In that case, in the process of etching the polysilicon film 14, the etching gas (F 2 gas) passes through the pores of the SiOCN film 15 and is supplied to the side wall of the SiGe film 11, and the side wall is etched. It ends up. The amine gas enters the pores of the SiOCN film 15 and is adsorbed on the pore walls to prevent the passage of F 2 gas in the pores. As a result, it has a role of preventing the supply of F 2 gas to the side wall of the SiGe film 11 and preventing etching of the side wall.
さらに、後の評価試験で示すようにアミンについては、ポリシリコン膜１４への吸着性が低い一方で、酸素を含有するシリコン膜であるＳｉＯＣＮ膜１５及び酸化シリコン膜１２への吸着性が高い。従って、上記のアミンガスの供給により、ＳｉＯＣＮ膜１５及び酸化シリコン膜１２の各々の表面は、アミンによる保護膜で被覆され、エッチングガスとの接触が防止される。それ故にこの保護膜によって、これらＳｉＯＣＮ膜１５及び酸化シリコン膜１２のエッチングが防止される。その一方でポリシリコン膜１４の表面には保護膜が形成されにくいので、当該ポリシリコン膜１４についてはエッチングされる。従って、ウエハＷの表面に露出するポリシリコン膜１４、ＳｉＯＣＮ膜１５及び酸化シリコン膜１２のうち、ポリシリコン膜１４のみが選択的にエッチングされる。なお、アミンはそのようにＳｉＯＣＮ膜１５への吸着性が高いので、上記した当該ＳｉＯＣＮ膜１５の孔壁への吸着によるＦ２ガスの通過防止性能は高い。 Further, as will be shown in a later evaluation test, amine has low adsorptivity to the polysilicon film 14, while has high adsorptivity to the SiOCN film 15 and the silicon oxide film 12 which are oxygen-containing silicon films. Therefore, by supplying the amine gas, the surfaces of the SiOCN film 15 and the silicon oxide film 12 are each coated with a protective film of amine, and contact with the etching gas is prevented. Therefore, this protective film prevents etching of the SiOCN film 15 and the silicon oxide film 12. On the other hand, since it is difficult for a protective film to be formed on the surface of the polysilicon film 14, the polysilicon film 14 is etched. Therefore, of the polysilicon film 14, SiOCN film 15, and silicon oxide film 12 exposed on the surface of the wafer W, only the polysilicon film 14 is selectively etched. Since amine has such high adsorptivity to the SiOCN film 15, the performance of preventing the passage of F 2 gas by adsorbing the SiOCN film 15 to the pore wall is high.
続いて、図２～図５を参照して、ウエハＷに対して行われる処理について、順を追って説明する。これらの図２～図５は、図１で説明したウエハＷの表面部が処理によって変化する様子を示す模式図であり、これらの各図で示す処理は、ウエハＷが処理容器に搬入され、当該処理容器内が排気されて所定の圧力の真空雰囲気とされた状態で行われる。図中、ＳｉＯＣＮ膜１５に形成されている孔部を１６としている。また、ウエハＷに供給するアミンを２１として示しており、このアミン２１は、この実施形態では例えばブチルアミン（Ｃ４Ｈ１１Ｎ）である。また、Ｆ２ガスを２２として示す。そして、上記のアミン２１によりＳｉＯＣＮ膜１５及び酸化シリコン膜１２の各々の表面に形成される保護膜を２３として示す。 Subsequently, with reference to FIGS. 2 to 5, the processing performed on the wafer W will be described step by step. 2 to 5 are schematic views showing how the surface portion of the wafer W described with reference to FIG. 1 changes depending on the processing. In the processing shown in each of these drawings, the wafer W is carried into the processing container. This is performed in a state where the inside of the processing container is exhausted to create a vacuum atmosphere at a predetermined pressure. In the figure, 16 is a hole formed in the SiOCN film 15. Also shows the amine to be supplied to the wafer W as 21, the amine 21, in this embodiment, for example butylamine (C 4 H 11 N). Further, F 2 gas is shown as 22. The protective film formed on the surfaces of the SiOCN film 15 and the silicon oxide film 12 by the amine 21 is shown as 23.
先ず、処理容器内にアミン２１として、アミンガス（ガス状態のアミン２１）が供給される（ステップＳ１、図２Ａ、図２Ｂ）。上記したようにアミン２１はＳｉＯＣＮ膜１５に吸着しやすいため、孔部１６を形成する孔壁に比較的多くのアミン２１が吸着して留まり、当該孔部１６が封止される。また、当該アミン２１は、ＳｉＯＣＮ膜１５の他に酸化シリコン膜１２にも吸着しやすいため、これらＳｉＯＣＮ膜１５及び酸化シリコン膜１２の上面に、アミン２１により構成される保護膜２３が形成される。 First, amine gas (amine 21 in a gas state) is supplied as amine 21 into the processing container (step S1, FIG. 2A, FIG. 2B). As described above, since the amine 21 is easily adsorbed on the SiOCN film 15, a relatively large amount of amine 21 is adsorbed and stays on the pore wall forming the pore 16, and the pore 16 is sealed. Further, since the amine 21 is easily adsorbed on the silicon oxide film 12 in addition to the SiOCN film 15, a protective film 23 composed of the amine 21 is formed on the upper surfaces of the SiOCN film 15 and the silicon oxide film 12. ..
続いて、処理容器内へのアミンガスの供給が停止し、処理容器内においては排気と例えばＮ２（窒素）ガスであるパージガスの供給とが行われる状態となる（ステップＳ２、図２Ｃ）。それにより、孔部１６に流入せず保護膜２３を形成していないアミンガスについては、排気されるパージガスの気流に乗って除去される。 Subsequently, the supply of the amine gas into the processing container is stopped, and the exhaust gas and, for example , the purge gas, which is N 2 (nitrogen) gas, are supplied in the processing container (step S2, FIG. 2C). As a result, the amine gas that does not flow into the pores 16 and does not form the protective film 23 is removed by the air flow of the exhausted purge gas.
続いて、処理容器内にＦ２ガス２２が供給され、ポリシリコン膜１４がエッチングされて、ＳｉＯＣＮ膜１５の上部側の側壁が露出する（ステップＳ３、図３Ａ）。このエッチングの進行中、ＳｉＯＣＮ膜１５の上部側の孔部１６にはアミン２１が留まっており、当該アミン２１によってＦ２ガス２２が孔部１６を通過してＳｉＧｅ膜１１に到達することが防止される。また保護膜２３に被覆されているため、ＳｉＯＣＮ膜１５及び酸化シリコン膜１２の上面は、Ｆ２ガス２２によってエッチングされることが防止される。従って、酸化シリコン膜１２、ＳｉＯＣＮ膜１５、ポリシリコン膜１４のうち、ポリシリコン膜１４が選択的にエッチングされる。なお、ウエハＷの表面に吸着されているアミン２１によってＦ２ガス２２は活性化され、上記したようにポリシリコン膜１４は比較的高いエッチングレートでエッチングされる。 Subsequently, the F 2 gas 22 is supplied into the processing container, the polysilicon film 14 is etched, and the side wall on the upper side of the SiOCN film 15 is exposed (step S3, FIG. 3A). During the progress of this etching, the amine 21 remains in the pores 16 on the upper side of the SiOCN film 15, and the amine 21 prevents the F 2 gas 22 from passing through the pores 16 and reaching the SiGe film 11. Will be done. Further, since the protective film 23 is coated, the upper surfaces of the SiOCN film 15 and the silicon oxide film 12 are prevented from being etched by the F 2 gas 22. Therefore, among the silicon oxide film 12, the SiOCN film 15, and the polysilicon film 14, the polysilicon film 14 is selectively etched. The F 2 gas 22 is activated by the amine 21 adsorbed on the surface of the wafer W, and the polysilicon film 14 is etched at a relatively high etching rate as described above.
その後、処理容器内へのＦ２ガス２２の供給が停止し、処理容器内においては排気とパージガスの供給とが行われる状態となり（ステップＳ４、図３Ｂ）、処理容器内に残留するＦ２ガス２２は、処理容器内から排気されるパージガスの気流に乗って除去される。続いて、処理容器内にアミンガスが供給される。即ち、再度ステップＳ１が実行される。上記のステップＳ３でポリシリコン膜１４がエッチングされて、ＳｉＯＣＮ膜１５の上部側の側壁が露出している。従って、この２回目のステップＳ１で供給されるアミン２１は、ＳｉＯＣＮ膜１５において１回目のステップＳ１でアミン２１が供給された孔部１６よりも下方の孔部１６に供給されて、孔壁に吸着される（図４Ａ）。また、露出したＳｉＯＣＮ膜１５の側壁にも保護膜２３が形成される。 After that, the supply of the F 2 gas 22 into the processing container is stopped, the exhaust gas and the purge gas are supplied in the processing container (step S4, FIG. 3B), and the F 2 gas remaining in the processing container is reached. 22 is removed by riding on the airflow of the purge gas exhausted from the processing container. Subsequently, amine gas is supplied into the processing container. That is, step S1 is executed again. In step S3 above, the polysilicon film 14 is etched to expose the upper side wall of the SiOCN film 15. Therefore, the amine 21 supplied in the second step S1 is supplied to the pore 16 below the pore 16 to which the amine 21 was supplied in the first step S1 in the SiOCN film 15, and is supplied to the pore wall. It is adsorbed (Fig. 4A). A protective film 23 is also formed on the side wall of the exposed SiOCN film 15.
その後、ステップＳ２の処理容器内における排気及びパージガスの供給が再度行われる。続いて、ステップＳ３の処理容器内へのＦ２ガス２２の供給が行われ、ポリシリコン膜１４が下方へ向けてさらにエッチングされ、ＳｉＯＣＮ膜１５の側壁において露出する領域が下方に向けて拡大する。このときもウエハＷの表面に吸着されているアミン２１によって活性化されたＦ２ガス２２により、ポリシリコン膜１４は高いエッチングレートでエッチングされる。 After that, the exhaust gas and the purge gas in the processing container of step S2 are supplied again. Subsequently, the F 2 gas 22 is supplied into the processing container in step S3, the polysilicon film 14 is further etched downward, and the exposed region on the side wall of the SiOCN film 15 expands downward. .. Also at this time, the polysilicon film 14 is etched at a high etching rate by the F 2 gas 22 activated by the amine 21 adsorbed on the surface of the wafer W.
上記のように２回目のステップＳ１によって、ＳｉＯＣＮ膜１５においてアミン２１が供給される領域が下方へと広げられていることにより、ポリシリコン膜１４のエッチングによって新たに露出するＳｉＯＣＮ膜１５の側壁付近の孔部１６には、当該アミン２１が留まっている。従って、この２回目のステップＳ３においても、エッチングガスがＳｉＯＣＮ膜１５の孔部１６を通過してＳｉＧｅ膜１１の側壁をエッチングすることを防ぐことができる。また、ＳｉＯＣＮ膜１５及び酸化シリコン膜１２の各々の上面と、ＳｉＯＣＮ膜の側面とに形成されている保護膜２３により、これらＳｉＯＣＮ膜１５及び酸化シリコン膜のエッチングが防止される（図４Ｂ）。このエッチング後、ステップＳ４の排気及びパージガスの供給が再度行われる。 As described above, in the second step S1, the region where the amine 21 is supplied in the SiOCN film 15 is expanded downward, so that the vicinity of the side wall of the SiOCN film 15 newly exposed by etching the polysilicon film 14 The amine 21 remains in the pore 16 of the. Therefore, also in this second step S3, it is possible to prevent the etching gas from passing through the pores 16 of the SiOCN film 15 and etching the side wall of the SiGe film 11. Further, the protective film 23 formed on the upper surface of each of the SiOCN film 15 and the silicon oxide film 12 and the side surface of the SiOCN film prevents etching of the SiOCN film 15 and the silicon oxide film (FIG. 4B). After this etching, the exhaust gas and purge gas supply in step S4 are performed again.
このように順番に行われるステップＳ１～Ｓ４を一つのサイクルとすると、例えば上記の２回目のステップＳ４が行われた後も、当該サイクルが繰り返し行われる。それにより、ＳｉＯＣＮ膜１５、ＳｉＧｅ膜１１及び酸化シリコン膜１２についてはエッチングが防止されつつ、ポリシリコン膜１４が下方へとエッチングされる。 Assuming that steps S1 to S4 performed in this order are one cycle, the cycle is repeated even after the second step S4 is performed, for example. As a result, the polysilicon film 14 is etched downward while the SiOCN film 15, the SiGe film 11 and the silicon oxide film 12 are prevented from being etched.
そして、例えばポリシリコン膜１４が全てエッチングされて、所定の回数のサイクルが終了すると（図５Ａ）、ウエハＷが加熱される（ステップＳ５）。その加熱により、孔部１６に進入したアミン２１及び保護膜２３を形成しているアミン２１が気化し、ウエハＷから除去される（図５Ｂ）。 Then, for example, when all the polysilicon films 14 are etched and a predetermined number of cycles are completed (FIG. 5A), the wafer W is heated (step S5). By the heating, the amine 21 that has entered the pore 16 and the amine 21 that forms the protective film 23 are vaporized and removed from the wafer W (FIG. 5B).
なお、上記の一連の処理においてエッチングの際にはアミン２１がウエハＷ表面に留まるものとして説明してきたが、Ｆ２ガス２２と反応することで反応生成物となってウエハＷ表面に留まっていることも考えられ、そのように反応生成物として留まっていてもよい。そして、そのように反応生成物が生じている場合、ステップＳ５では当該反応生成物が除去されるように加熱が行われる。つまり、このステップＳ５の加熱はアミン２１及び／または反応生成物を除去するための加熱であり、具体的には例えば１００℃～４００℃にウエハＷが加熱される。図６はステップＳ５の実施後のウエハＷの表面部を示しており、ポリシリコン膜１４が除去されることで形成された凹部１７内には、例えば後の工程で半導体装置のゲートが形成される。 Although it has been described that the amine 21 stays on the wafer W surface during etching in the above series of treatments, it reacts with the F 2 gas 22 to become a reaction product and stays on the wafer W surface. It is also possible that it may remain as a reaction product as such. Then, when such a reaction product is generated, heating is performed so that the reaction product is removed in step S5. That is, the heating in step S5 is heating for removing the amine 21 and / or the reaction product, and specifically, the wafer W is heated to, for example, 100 ° C. to 400 ° C. FIG. 6 shows the surface portion of the wafer W after the execution of step S5. In the recess 17 formed by removing the polysilicon film 14, for example, a gate of a semiconductor device is formed in a later step. NS.
上記の実施形態の処理によれば、ポリシリコン膜１４が比較的高いエッチングレートにてエッチングされるので、ステップＳ１～Ｓ４の繰り返しに要する時間を短くすることができる。従って、半導体装置の生産効率を高くすることができる。また、上記したようにアミン２１によりＳｉＯＣＮ膜１５の孔部１６が封止されると共に、酸化シリコン膜１２を被覆するようにアミン２１からなる保護膜２３が形成されることで当該酸化シリコン膜１２のエッチングが防止される。従って、ＳｉＯＣＮ膜１５の側方且つ酸化シリコン膜１２の下方に位置するＳｉＧｅ膜１１について、側方からのエッチング及び上方からエッチングが各々防止される。従って、半導体装置の歩留りの低下を抑制することができる。 According to the treatment of the above embodiment, since the polysilicon film 14 is etched at a relatively high etching rate, the time required for repeating steps S1 to S4 can be shortened. Therefore, the production efficiency of the semiconductor device can be increased. Further, as described above, the pores 16 of the SiOCN film 15 are sealed by the amine 21, and the protective film 23 made of the amine 21 is formed so as to cover the silicon oxide film 12, so that the silicon oxide film 12 is formed. Etching is prevented. Therefore, etching from the side and etching from above are prevented for the SiGe film 11 located on the side of the SiOCN film 15 and below the silicon oxide film 12. Therefore, it is possible to suppress a decrease in the yield of the semiconductor device.
ところで、特許文献１に記載されるようにポリシリコン膜をエッチングするにあたり、Ｆ２ガス及びＮＨ３ガスを用いることができる。しかし、上記の実施形態の処理では、孔部１６のエッチングガスの通過を防止するためのアミンガスをエッチングに利用し、ＮＨ３ガスのウエハＷへの供給については行わなくてもよい。つまり上記の実施形態の処理は、ＳｉＧｅ膜１１の保護のためにアミンガスを供給し、且つポリシリコン膜１４のエッチングのためにエッチングガス及びＮＨ３ガスを供給する処理を行う場合に比べて、ＮＨ３ガスの供給が不要となっている。そのため、上記の図２～図５で示した一連の処理を行う装置について、ＮＨ３ガスの供給系を設ける必要が無い。即ち、上記の実施形態の処理によれば、処理に要するガスの種類の増加を防ぎ、処理装置の製造コストや運用コストの上昇を抑えることができる。 By the way, F 2 gas and NH 3 gas can be used for etching the polysilicon film as described in Patent Document 1. However, in the treatment of the above embodiment, the amine gas for preventing the etching gas from passing through the pores 16 is used for etching, and the NH 3 gas may not be supplied to the wafer W. That is, in the treatment of the above embodiment, NH is compared with the case where the amine gas is supplied for the protection of the SiGe film 11 and the etching gas and the NH 3 gas are supplied for the etching of the polysilicon film 14. 3 Gas supply is no longer required. Therefore, it is not necessary to provide an NH 3 gas supply system for the device that performs the series of processes shown in FIGS. 2 to 5 above. That is, according to the treatment of the above embodiment, it is possible to prevent an increase in the types of gas required for the treatment and suppress an increase in the manufacturing cost and the operating cost of the treatment apparatus.
また、上記のステップＳ１～Ｓ４において処理容器の排気流量は一定であってもよいし、処理容器内の不要なガスを除去するためのステップＳ２、Ｓ４における排気流量についてはより確実にガスを除去することができるように、ステップＳ１、Ｓ３の排気流量よりも大きくしてもよい。また、ステップＳ２、Ｓ４ではパージガスの供給を行わず、排気のみによって不要なガスを除去するようにしてもよい。 Further, the exhaust flow rate of the processing container may be constant in steps S1 to S4 described above, and the exhaust flow rate in steps S2 and S4 for removing unnecessary gas in the processing container is more reliably removed. It may be larger than the exhaust flow rate of steps S1 and S3 so as to be able to do so. Further, in steps S2 and S4, unnecessary gas may be removed only by exhaust gas without supplying purge gas.
ところで、図１で示したウエハＷの膜構造としては一例であり、Ｆ２ガス及びアミンガスの供給によりエッチングされるＳｉ膜としてはポリシリコン膜１４に限られず、例えばアモルファスシリコン膜であってもよい。上記の実施形態ではエッチング非対象膜はＳｉＧｅ膜１１であるが、例えばＳｉ膜であってもよい。また、エッチング非対象膜については、これらＳｉ膜やＳｉＧｅ膜１１のようなシリコン含有膜以外の膜であってもよい。さらに、ＳｉＧｅ膜１１上に設けられるマスク膜としては、エッチング時にＳｉＧｅ膜１１が上方側からエッチングされることを抑制できればよいので、酸化シリコン膜１２であることには限られない。 Incidentally, an example is a film structure of the wafer W shown in FIG. 1, as the Si film is etched by the supply of F 2 gas and amine gas is not limited to the polysilicon film 14 may be, for example, amorphous silicon film .. In the above embodiment, the non-etching film is the SiGe film 11, but it may be, for example, a Si film. Further, the non-etching film may be a film other than the silicon-containing film such as these Si film and SiGe film 11. Further, the mask film provided on the SiGe film 11 is not limited to the silicon oxide film 12 as long as it can suppress the etching of the SiGe film 11 from the upper side at the time of etching.
また、この酸化シリコン膜１２が設けられる代わりに、ＳｉＧｅ膜１１の上側がＳｉＯＣＮ膜１５により覆われる構成であってもよい。つまり、ＳｉＯＣＮ膜１５がＳｉＧｅ膜１１の側方から上方に亘って設けられる構成とする。その場合、ウエハＷにエッチングガスが供給されるときにはアミンガスがＳｉＧｅ膜１１の上側を覆うＳｉＯＣＮ膜１５に吸着した状態となるので、ＳｉＧｅ膜１１の上側からエッチングガスが当該ＳｉＧｅ膜１１に接触することが防止される。さらに、多孔質膜についてもＳｉＯＣＮ膜１５には限られず、ＳｉＯＣＮ膜１５の代わりにＳｉＣＯ膜、ＳｉＣＯＨ膜などの多孔質膜が形成されていてもよい。評価試験で示すように酸素を含有するシリコン膜にアミンは吸着しやすいので、多孔質膜は、アミンを吸着させるために酸素を含むことが好ましい。なお、ここでいう酸素を含むとは、不純物として酸素を含む意味ではなく、膜を構成する成分として酸素を含むという意味である。 Further, instead of providing the silicon oxide film 12, the upper side of the SiGe film 11 may be covered with the SiOCN film 15. That is, the SiOCN film 15 is provided from the side to the upper side of the SiGe film 11. In that case, when the etching gas is supplied to the wafer W, the amine gas is adsorbed on the SiOCN film 15 covering the upper side of the SiGe film 11, so that the etching gas comes into contact with the SiGe film 11 from the upper side of the SiGe film 11. Is prevented. Further, the porous film is not limited to the SiOCN film 15, and a porous film such as a SiCO film or a SiCOH film may be formed instead of the SiOCN film 15. As shown in the evaluation test, amines are easily adsorbed on the oxygen-containing silicon membrane, so that the porous membrane preferably contains oxygen in order to adsorb the amine. The term "containing oxygen" as used herein does not mean that oxygen is contained as an impurity, but means that oxygen is contained as a component constituting the film.
上記の実施形態においてはステップＳ１～Ｓ４を３回以上繰り返すように示したが、繰り返しの回数は上記の例に限られず、例えば２回であってもよい。また、繰り返しを行わず、ステップＳ１～Ｓ４を１回のみ行ってもよい。ところで、不要なガスを除去する上記のステップＳ２、Ｓ４は省いてもよい。具体的に、処理容器内へのアミンガス、Ｆ２ガスの供給のタイミングを夫々示す図７Ａに表すように、アミンガス及びＦ２ガスのうち、一方のガスの供給終了時から間隔を空けずに他方のガスを供給するようにしてもよい。そのようにステップＳ２、Ｓ４を省く場合も、アミンガス、Ｆ２ガスを夫々供給するステップＳ１、Ｓ３については、繰り返し行うことに限られず、１回のみ行うようにしてもよい。 In the above embodiment, steps S1 to S4 are shown to be repeated three or more times, but the number of repetitions is not limited to the above example, and may be, for example, two times. Further, steps S1 to S4 may be performed only once without repeating. By the way, the above steps S2 and S4 for removing unnecessary gas may be omitted. Specifically, as shown in FIG. 7A, which shows the timing of supplying the amine gas and the F 2 gas into the processing container, respectively, the other of the amine gas and the F 2 gas is not spaced from the end of the supply. Gas may be supplied. May so omit steps S2, S4, amine gas, for F 2 gas step for supplying respectively S1, S3, not limited to be repeated, may be performed only once.
また、アミンガス及びＦ２ガス２２は順番に供給することに限られない。つまり、アミンガス及びＦ２ガス２２のうち、一方のガスの供給終了後に他方のガスの供給を開始することには限られず、図７Ｂに示すように、アミンガス及びＦ２ガス２２を同時にウエハＷに供給して処理を行ってもよい。このようにアミンガス及びＦ２ガス２２を同時に供給する場合は、アミンガスによる孔部１６の封止及び保護膜２３の形成を行いながら、Ｆ２ガス２２によるポリシリコン膜１４のエッチングが行われる。 Further, the amine gas and the F 2 gas 22 are not limited to being supplied in order. That is, of the amine gas and F 2 gas 22 is not limited to starting the supply of one gas the other gas after completion of the supply of, as shown in FIG. 7B, at the same time the wafer W the amine gas and F 2 gas 22 It may be supplied and processed. When the amine gas and the F 2 gas 22 are supplied at the same time in this way, the polysilicon film 14 is etched by the F 2 gas 22 while sealing the pores 16 with the amine gas and forming the protective film 23.
さらに上記のように、ステップＳ５ではアミン２１及び／またはアミン２１とＦ２ガスとの反応生成物がＳｉＯＣＮ膜１５から除去されるようにウエハＷを加熱している。しかし、アミン２１及び／または反応生成物がＳｉＯＣＮ膜１５の孔部１６に残留していてもＳｉＯＣＮ膜１５の誘電率が実用上問題無ければ、アミン２１及び反応生成物が残留していてもよいことが考えられる。従って、ステップＳ５の加熱処理は必須とは限られない。 Further, as described above, in step S5, the wafer W is heated so that the reaction product of the amine 21 and / or the amine 21 and the F 2 gas is removed from the SiOCN film 15. However, even if the amine 21 and / or the reaction product remains in the pores 16 of the SiOCN film 15, the amine 21 and the reaction product may remain as long as the dielectric constant of the SiOCN film 15 is not practically problematic. Can be considered. Therefore, the heat treatment in step S5 is not always essential.
またアミンガスを構成するアミン２１については、ブチルアミンであることに限られない。具体例を列挙しておくと、ヘキシルアミン、ジプロピルアミン、ｎ－オクチルアミン、tertブチルアミン、デシルアミン、ドデシルアミン、ジシクロヘキシルアミン、テトラデシルアミンなどが挙げられる。このように例示した各アミンの沸点は１００℃～４００℃の範囲内に含まれている。従って上記の実施形態のステップＳ５でアミンを気化状態として除去するためには、そのように１００℃～４００℃にウエハＷを加熱することが好ましい。 Further, the amine 21 constituting the amine gas is not limited to butylamine. Specific examples include hexylamine, dipropylamine, n-octylamine, tertbutylamine, decylamine, dodecylamine, dicyclohexylamine, tetradecylamine and the like. The boiling point of each amine thus exemplified is contained in the range of 100 ° C. to 400 ° C. Therefore, in order to remove the amine as a vaporized state in step S5 of the above embodiment, it is preferable to heat the wafer W to 100 ° C. to 400 ° C. in this way.
続いて、既述した一連の処理を行うための基板処理装置３について、図８の平面図を参照して説明する。基板処理装置３は、ウエハＷを搬入出するための搬入出部３１と、搬入出部３１に隣接して設けられた２つのロードロック室４１と、２つのロードロック室４１に各々隣接して設けられた、２つの熱処理モジュール４０と、２つの熱処理モジュール４０に各々隣接して設けられた２つのエッチングモジュール５と、を備えている。 Subsequently, the substrate processing apparatus 3 for performing the series of processing described above will be described with reference to the plan view of FIG. The substrate processing device 3 is adjacent to the loading / unloading section 31 for loading / unloading the wafer W, the two load lock chambers 41 provided adjacent to the loading / unloading section 31, and the two load lock chambers 41, respectively. It includes two heat treatment modules 40 provided and two etching modules 5 provided adjacent to each of the two heat treatment modules 40.
　搬入出部３１は、第１の基板搬送機構３２が設けられると共に常圧雰囲気とされる常圧搬送室３３と、当該常圧搬送室３３の側部に設けられた、ウエハＷを収納するキャリア３４が載置されるキャリア用載置台３５と、を備えている。図中３６は常圧搬送室３３に隣接するオリエンタ室であり、ウエハＷを回転させて偏心量を光学的に求め、第１の基板搬送機構３２に対するウエハＷの位置合わせを行うために設けられる。第１の基板搬送機構３２は、キャリア用載置台３５上のキャリア３４とオリエンタ室３６とロードロック室４１との間でウエハＷを搬送する。 The carry-in / out section 31 is provided with a first substrate transport mechanism 32 and a normal pressure transport chamber 33 having a normal pressure atmosphere, and a carrier provided on the side of the normal pressure transport chamber 33 for accommodating the wafer W. It is provided with a carrier mounting table 35 on which the 34 is mounted. Reference numeral 36 denotes an orientation chamber adjacent to the normal pressure transfer chamber 33, which is provided to rotate the wafer W to optically determine the amount of eccentricity and align the wafer W with respect to the first substrate transfer mechanism 32. .. The first substrate transport mechanism 32 transports the wafer W between the carrier 34 on the carrier mounting table 35, the oriental chamber 36, and the load lock chamber 41.
　各ロードロック室４１内には、例えば多関節アーム構造を有する第２の基板搬送機構４２が設けられており、当該第２の基板搬送機構４２は、ウエハＷをロードロック室４１と熱処理モジュール４０とエッチングモジュール５との間で搬送する。熱処理モジュール４０を構成する処理容器内及びエッチングモジュール５を構成する処理容器内は、真空雰囲気とされており、ロードロック室４１内は、これらの真空雰囲気の処理容器内と常圧搬送室３３との間でウエハＷの受け渡しを行えるように、常圧雰囲気と真空雰囲気とが切り替えられる。 In each load lock chamber 41, for example, a second substrate transfer mechanism 42 having an articulated arm structure is provided, and the second substrate transfer mechanism 42 uses the wafer W as the load lock chamber 41 and the heat treatment module 40. And the etching module 5. The inside of the processing container constituting the heat treatment module 40 and the inside of the processing container forming the etching module 5 have a vacuum atmosphere, and the inside of the load lock chamber 41 includes the inside of the processing container having such a vacuum atmosphere and the normal pressure transfer chamber 33. The normal pressure atmosphere and the vacuum atmosphere are switched so that the wafer W can be transferred between the two.
図中４３は開閉自在なゲートバルブであり、常圧搬送室３３とロードロック室４１との間、ロードロック室４１と熱処理モジュール４０との間、熱処理モジュール４０とエッチングモジュール５との間に各々設けられている。熱処理モジュール４０については、上記の処理容器、当該処理容器内を排気して真空雰囲気を形成するための排気機構及び処理容器内に設けられると共に載置されたウエハＷを加熱可能な載置台などを含み、既述のステップＳ５を実行できるように構成されている。 In the figure, 43 is a gate valve that can be opened and closed, and is between the normal pressure transfer chamber 33 and the load lock chamber 41, between the load lock chamber 41 and the heat treatment module 40, and between the heat treatment module 40 and the etching module 5, respectively. It is provided. Regarding the heat treatment module 40, the above-mentioned processing container, an exhaust mechanism for exhausting the inside of the processing container to form a vacuum atmosphere, a mounting table provided in the processing container and capable of heating the mounted wafer W, and the like are provided. Including, it is configured so that the above-mentioned step S5 can be executed.
続いて、エッチングモジュール５について図９の縦断側面図を参照しながら説明する。このエッチングモジュール５はウエハＷにステップＳ１～Ｓ４の処理を行うモジュールであり、例えば円形の処理容器５１を備えている。つまり、ステップＳ１～Ｓ４の処理は、同じ処理容器内で行われる。処理容器５１は気密な真空容器であり、当該処理容器５１内の下部側には、水平に形成された表面（上面）にウエハＷを載置する、円形の載置台（ステージ）６１が設けられている。図中６２は、載置台６１に埋設されたステージヒーターであり、上記のステップＳ１～Ｓ４の処理が行えるようにウエハＷを所定の温度に加熱する。図中６３は、載置部である載置台６１を処理容器５１の底面に支持する支柱である。図中６４は垂直な昇降ピンであり、昇降機構６５により載置台６１の表面を突没し、既述の第２の基板搬送機構４２と載置台６１との間でウエハＷの受け渡しを行う。昇降ピン６４は３つ設けられるが、２つのみ図示している Subsequently, the etching module 5 will be described with reference to the longitudinal side view of FIG. The etching module 5 is a module that performs the processing of steps S1 to S4 on the wafer W, and includes, for example, a circular processing container 51. That is, the processes of steps S1 to S4 are performed in the same processing container. The processing container 51 is an airtight vacuum container, and a circular mounting table (stage) 61 on which the wafer W is placed on a horizontally formed surface (upper surface) is provided on the lower side of the processing container 51. ing. In the figure, reference numeral 62 denotes a stage heater embedded in the mounting table 61, which heats the wafer W to a predetermined temperature so that the above steps S1 to S4 can be performed. Reference numeral 63 denotes a support column that supports the mounting table 61, which is a mounting portion, on the bottom surface of the processing container 51. In the figure, 64 is a vertical elevating pin, and the surface of the mounting table 61 is recessed by the elevating mechanism 65, and the wafer W is transferred between the second substrate transport mechanism 42 and the mounting table 61 described above. Three lifting pins 64 are provided, but only two are shown.
図中６６は、処理容器５１の側壁に設けられた側壁ヒーターであり、処理容器５１内の雰囲気の温度を調整する。なお、処理容器５１の側壁には図示しない開閉自在なウエハＷの搬送口が設けられている。図中６７は処理容器５１の底面に開口した排気口であり、排気管を介して真空ポンプ及びバルブなどにより構成される排気機構６８に接続されている。排気機構６８による排気口６７からの排気流量が調整されることにより、処理容器５１内の圧力が調整される。 In the figure, reference numeral 66 denotes a side wall heater provided on the side wall of the processing container 51, which adjusts the temperature of the atmosphere inside the processing container 51. The side wall of the processing container 51 is provided with a transfer port for the wafer W which can be opened and closed (not shown). In the figure, 67 is an exhaust port opened on the bottom surface of the processing container 51, and is connected to an exhaust mechanism 68 composed of a vacuum pump, a valve, and the like via an exhaust pipe. By adjusting the exhaust flow rate from the exhaust port 67 by the exhaust mechanism 68, the pressure in the processing container 51 is adjusted.
載置台６１の上方で処理容器５１の天井部には、ガス供給部を構成するガスシャワーヘッド７が、当該載置台６１に対向するように設けられている。ガスシャワーヘッド７は、シャワープレート７１、ガス拡散空間７２及び拡散板７３を備えている。シャワープレート７１は、ガスシャワーヘッド７の下面部をなすように水平に設けられ、載置台６１にシャワー状にガスを吐出するために、ガス吐出孔７４が多数分散して形成されている。ガス拡散空間７２は各ガス吐出孔７４にガスを供給するために、その下方側がシャワープレート７１によって区画されるように形成された扁平な空間である。このガス拡散空間７２を上下に分割するように拡散板７３が水平に設けられている。図中７５は、拡散板７３に形成される貫通孔であり、拡散板７３に多数、分散して穿孔されている。図中７７は天井ヒーターであり、ガスシャワーヘッド７の温度を調整する。 Above the mounting table 61, on the ceiling of the processing container 51, a gas shower head 7 constituting a gas supply unit is provided so as to face the mounting table 61. The gas shower head 7 includes a shower plate 71, a gas diffusion space 72, and a diffusion plate 73. The shower plate 71 is horizontally provided so as to form a lower surface portion of the gas shower head 7, and a large number of gas discharge holes 74 are dispersed and formed in order to discharge gas into the mounting table 61 in a shower shape. The gas diffusion space 72 is a flat space formed so that the lower side thereof is partitioned by the shower plate 71 in order to supply gas to each gas discharge hole 74. A diffusion plate 73 is horizontally provided so as to divide the gas diffusion space 72 into upper and lower parts. Reference numeral 75 in the figure is a through hole formed in the diffusion plate 73, and a large number of through holes are dispersed and perforated in the diffusion plate 73. Reference numeral 77 in the figure is a ceiling heater, which adjusts the temperature of the gas shower head 7.
ガス拡散空間７２の上部側には、ガス供給管７８、８１の下流端が接続されている。ガス供給管７８の上流側は、流量調整部７９を介してＦ２ガスの供給源７０に接続されている。流量調整部７９は、バルブやマスフローコントローラにより構成されており、ガス供給管７８の下流側へ供給されるガスの流量を調整する。なお後述の各流量調整部についても、流量調整部７９と同様に構成されており、流量調整部が介設される管の下流側へ供給されるガスの流量を調整する。 The downstream ends of the gas supply pipes 78 and 81 are connected to the upper side of the gas diffusion space 72. The upstream side of the gas supply pipe 78 is connected to the F 2 gas supply source 70 via the flow rate adjusting unit 79. The flow rate adjusting unit 79 is composed of a valve and a mass flow controller, and adjusts the flow rate of the gas supplied to the downstream side of the gas supply pipe 78. Each flow rate adjusting unit, which will be described later, has the same configuration as the flow rate adjusting unit 79, and adjusts the flow rate of the gas supplied to the downstream side of the pipe through which the flow rate adjusting unit is provided.
ガス供給管８１の上流側は、流量調整部８２を介して液体のアミンが貯留されるタンク８３に接続されている。タンク８３は内部のアミンを加熱して気化させるヒーターを備えており、そのように気化したアミン（アミンガス）をガス供給管８１の下流側に供給することができるように構成されている。また、例えばガス供給管８１は、流量調整部８２の上流側で分岐してガス供給管８４を形成する。ガス供給管８４は流量調整部８５を介してＮ２（窒素）供給源８６に接続されている。従って、アミンガス、Ｎ２ガスを各々独立してガスシャワーヘッド７に供給することができる。なお、図中５２はガス供給管８１に設けられるヒーターである。 The upstream side of the gas supply pipe 81 is connected to the tank 83 in which the liquid amine is stored via the flow rate adjusting unit 82. The tank 83 is provided with a heater that heats and vaporizes the amine inside, and is configured to be able to supply the vaporized amine (amine gas) to the downstream side of the gas supply pipe 81. Further, for example, the gas supply pipe 81 branches on the upstream side of the flow rate adjusting unit 82 to form the gas supply pipe 84. The gas supply pipe 84 is connected to the N 2 (nitrogen) supply source 86 via the flow rate adjusting unit 85. Therefore, the amine gas and the N 2 gas can be independently supplied to the gas shower head 7. In the figure, 52 is a heater provided in the gas supply pipe 81.
エッチングモジュール５において実施される上記のステップＳ１～Ｓ４と、ガスシャワーヘッド７から供給されるガスとの対応について示しておく。ステップＳ１では、上記したタンク８３からアミンガスがガスシャワーヘッド７に供給され、処理容器５１内に供給される。ステップＳ２、Ｓ４では、Ｎ２ガス供給源８６からＮ２ガスがガスシャワーヘッド７に供給され、処理容器５１内にパージガスとして供給される。ステップＳ３では、タンク８３及びＮ２ガス供給源８６からのガスの供給は停止し、供給源７０からＦ２ガスがガスシャワーヘッド７に供給され、処理容器５１内に供給される。 The correspondence between the above steps S1 to S4 performed in the etching module 5 and the gas supplied from the gas shower head 7 will be described. In step S1, amine gas is supplied to the gas shower head 7 from the tank 83 described above, and is supplied into the processing container 51. In step S2, S4, N 2 gas from the N 2 gas supply source 86 is supplied to the gas shower head 7, is supplied as a purge gas into the processing vessel 51. In step S3, the supply of gas from the tank 83 and the N 2 gas supply source 86 is stopped, the F 2 gas is supplied from the supply source 70 to the gas shower head 7, and is supplied into the processing container 51.
既述したステップＳ１～Ｓ４の各処理を行うにあたり、ウエハＷの温度は例えば０℃～１５０℃とされる。また、処理時の処理容器５１内の圧力は、例えば１３．３Ｐａ（１００ｍＴｏｒｒ）～６６６．５Ｐａ（５０００ｍＴｏｒｒ）とされる。また、処理容器５１内に供給するＦ２ガスの流量は例えば１００ｓｃｃｍ～２０００ｓｃｃｍであり、処理容器５１内に供給するブチルアミン等のアミンガスの流量は、例えば１ｓｃｃｍ～５００ｓｃｃｍである。 In performing each of the processes of steps S1 to S4 described above, the temperature of the wafer W is set to, for example, 0 ° C. to 150 ° C. The pressure in the processing container 51 during processing is, for example, 13.3 Pa (100 mTorr) to 666.5 Pa (5000 mTorr). The flow rate of the F 2 gas supplied into the processing container 51 is, for example, 100 sccm to 2000 sccm, and the flow rate of the amine gas such as butylamine supplied into the processing container 51 is, for example, 1 sccm to 500 sccm.
　ところで、図８、図９に示すように基板処理装置３はコンピュータである制御部３０を備えており、この制御部３０は、プログラム、メモリ、ＣＰＵを備えている。プログラムには、既述したウエハＷの処理及びウエハＷの搬送が行われるように命令（各ステップ）が組み込まれており、このプログラムは、コンピュータ記憶媒体、例えばコンパクトディスク、ハードディスク、光磁気ディスク、ＤＶＤ等に格納され、制御部３０にインストールされる。制御部３０は当該プログラムにより基板処理装置３の各部に制御信号を出力し、各部の動作を制御する。具体的には、エッチングモジュール５の動作、熱処理モジュール４０の動作、第１の基板搬送機構３２、第２の基板搬送機構４２の動作、オリエンタ室３６の動作が制御信号により制御される。上記のエッチングモジュール５の動作としては、各ヒーターの出力の調整、ガスシャワーヘッド７からの各ガスの給断、排気機構６８による排気流量の調整、昇降機構６５による昇降ピン６４の昇降などの各動作が含まれる。この制御部３０及びエッチングモジュール５により、エッチング装置が構成される。 By the way, as shown in FIGS. 8 and 9, the substrate processing device 3 includes a control unit 30 which is a computer, and the control unit 30 includes a program, a memory, and a CPU. The program incorporates instructions (each step) for processing the wafer W and transporting the wafer W as described above, and the program includes computer storage media such as a compact disk, a hard disk, and a magneto-optical disk. It is stored in a DVD or the like and installed in the control unit 30. The control unit 30 outputs a control signal to each unit of the substrate processing device 3 by the program, and controls the operation of each unit. Specifically, the operation of the etching module 5, the operation of the heat treatment module 40, the operation of the first substrate transfer mechanism 32, the operation of the second substrate transfer mechanism 42, and the operation of the oriental chamber 36 are controlled by control signals. The operations of the etching module 5 include adjusting the output of each heater, supplying and stopping each gas from the gas shower head 7, adjusting the exhaust flow rate by the exhaust mechanism 68, and raising and lowering the lifting pin 64 by the lifting mechanism 65. The operation is included. An etching apparatus is configured by the control unit 30 and the etching module 5.
　基板処理装置３におけるウエハＷの搬送経路を説明する。図１で説明したように各膜が形成されたウエハＷを格納したキャリア３４がキャリア用載置台３５に載置される。そして、このウエハＷは、常圧搬送室３３→オリエンタ室３６→常圧搬送室３３→ロードロック室４１の順に搬送され、熱処理モジュール４０を介してエッチングモジュール５に搬送される。そして、既述のようにステップＳ１～Ｓ４からなるサイクルが繰り返し行われて、ウエハＷが処理される。続いて、ウエハＷは熱処理モジュール４０に搬送されてステップＳ５の処理を受ける。然る後、ウエハＷは、ロードロック室４１→常圧搬送室３３の順で搬送されて、キャリア３４に戻される。 The transfer path of the wafer W in the substrate processing apparatus 3 will be described. As described with reference to FIG. 1, a carrier 34 containing a wafer W on which each film is formed is placed on a carrier mounting table 35. Then, the wafer W is conveyed in the order of the normal pressure transfer chamber 33 → the oriental chamber 36 → the normal pressure transfer chamber 33 → the load lock chamber 41, and is conveyed to the etching module 5 via the heat treatment module 40. Then, as described above, the cycle consisting of steps S1 to S4 is repeatedly performed to process the wafer W. Subsequently, the wafer W is conveyed to the heat treatment module 40 and undergoes the process of step S5. After that, the wafer W is conveyed in the order of the load lock chamber 41 → the normal pressure transport chamber 33, and is returned to the carrier 34.
ところで、アミンガスの供給とエッチングガスの供給とを順番に行う場合、それらアミンガスの供給とエッチングガスの供給とは、互いに異なる処理容器内で行われ、搬送機構によりこれらの処理容器間でウエハＷが搬送される構成であってもよい。ただし、同一の処理容器内でこれらのガスの供給を行うことで、上記のサイクルを繰り返し行うにあたり、ウエハＷをモジュール間で搬送する時間を省くことができる。従って、基板処理装置３の構成によれば、スループットの向上を図ることができる。 By the way, when the supply of the amine gas and the supply of the etching gas are performed in order, the supply of the amine gas and the supply of the etching gas are performed in different processing containers, and the wafer W is moved between these processing containers by the transport mechanism. It may be configured to be transported. However, by supplying these gases in the same processing container, it is possible to save the time for transporting the wafer W between the modules in repeating the above cycle. Therefore, according to the configuration of the substrate processing device 3, the throughput can be improved.
なお、今回開示された実施形態は、全ての点で例示であって制限的なものではないと考えられるべきである。上記の実施形態は、添付の特許請求の範囲及びその趣旨を逸脱することなく、様々な形態で省略、置換、変更及び／または組み合わせが行われてもよい。 It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The above embodiments may be omitted, replaced, modified and / or combined in various forms without departing from the scope of the appended claims and their gist.
（評価試験）
本開示の技術に関連して行われた評価試験について説明する。
・評価試験１
評価試験１として、Ｆ２ガスと共にブチルアミンガスを基板上のＳｉ膜に供給することでエッチングを行った。この処理後にＳｉ膜のエッチング量（エッチングされた膜の厚さ）と、残留したＳｉ膜の表面のラフネスとを測定した。なお、このエッチング時の基板の温度、基板を格納する処理容器内の圧力、処理容器内へのＦ２ガスの流量、処理容器内へのブチルアミンガスの流量の各々については、実施形態で述べた範囲の値に設定して処理を行った。また比較試験１として、ブチルアミンガスの代わりにＮＨ３ガスを供給することを除いて評価試験１と同様にエッチングを行い、Ｓｉ膜のエッチング量とＳｉ膜の表面のラフネスとを測定した。 (Evaluation test)
An evaluation test conducted in connection with the technique of the present disclosure will be described.
・ Evaluation test 1
As evaluation test 1, etching was performed by supplying butylamine gas together with F 2 gas to the Si film on the substrate. After this treatment, the etching amount of the Si film (thickness of the etched film) and the roughness of the surface of the remaining Si film were measured. The temperature of the substrate at the time of etching, the pressure in the processing container for storing the substrate, the flow rate of F 2 gas into the processing container, and the flow rate of butylamine gas into the processing container are described in the embodiments. Processing was performed by setting the value in the range. Further, as a comparative test 1 , etching was performed in the same manner as in the evaluation test 1 except that NH 3 gas was supplied instead of the butylamine gas, and the etching amount of the Si film and the roughness of the surface of the Si film were measured.
図１０のグラフに、評価試験１及び比較試験１の結果を示している。グラフに示すように、エッチング量については評価試験１が６５．０ｎｍ、比較試験１が４６．０ｎｍであり、評価試験１の方が大きい。従って、実施形態で述べたようにＦ２ガス及びＮＨ３ガスを供給することで、単位時間あたりのエッチング量を大きくすることができる。 The graph of FIG. 10 shows the results of the evaluation test 1 and the comparative test 1. As shown in the graph, the etching amount is 65.0 nm in the evaluation test 1 and 46.0 nm in the comparative test 1, and the evaluation test 1 is larger. Therefore, by supplying the F 2 gas and the NH 3 gas as described in the embodiment, the etching amount per unit time can be increased.
またＳｉ膜の表面のラフネスについては、評価試験１が５．８ｎｍ、比較試験１が１２．６ｎｍであり、評価試験１の方が小さい。つまり、評価試験１の方がエッチング後のＳｉ膜のラフネスが抑制されている。上記の実施形態としては、Ｓｉ膜であるポリシリコン膜１４を全て除去する例を示したが、Ｓｉ膜の一部のみをエッチングする処理を行う場合にも本技術を適用することができる。その場合にＳｉ膜のエッチング後に行う各処理について、当該Ｓｉ膜の表面の凹凸の影響を受けて不具合が生じることを抑制することができるため有利である。 Regarding the roughness of the surface of the Si film, the evaluation test 1 has a roughness of 5.8 nm and the comparative test 1 has a roughness of 12.6 nm, and the evaluation test 1 is smaller. That is, in the evaluation test 1, the roughness of the Si film after etching is suppressed. In the above embodiment, an example of removing all the polysilicon film 14 which is a Si film has been shown, but this technique can also be applied to a process of etching only a part of the Si film. In that case, it is advantageous because it is possible to suppress the occurrence of defects due to the influence of the unevenness on the surface of the Si film for each treatment performed after the etching of the Si film.
・評価試験２
評価試験２として、各々Ｎ（窒素）を含む分子であるＮＨ３、ブチルアミン、ヘキシルアミン、トリメチルアミンについて、Ｓｉを含む各種の分子に対する吸着エネルギーをシミュレーションにより測定した。具体的にはＳｉ、ＳｉＣ（炭化シリコン）、ＳｉＮ（窒化シリコン）、ＳｉＯ２ＣＮ（＝ＳｉＯＣＮ）、及びＳｉＯ（酸化シリコン）に対する吸着エネルギーを測定した。 ・ Evaluation test 2
As evaluation test 2, the adsorption energies of various molecules containing Si for NH 3 , butylamine, hexylamine, and trimethylamine, which are molecules containing N (nitrogen), were measured by simulation. Specifically, the adsorption energies for Si, SiC (silicon carbide), SiN (silicon nitride), SiO 2 CN (= SiO CN), and SiO (silicon oxide) were measured.
図１１は、この評価試験２の結果を示す棒グラフである。グラフの縦軸は吸着エネルギー（単位：ｅＶ）を示しており、当該吸着エネルギーが低いほど吸着しやすい。この図１１に示すようにＳｉ、ＳｉＣ及びＳｉＮに対しては、ＮＨ３、ブチルアミン、ヘキシルアミン及びトリメチルアミンのうちのいずれも吸着し難い。しかしＳｉＯ２ＣＮ及びＳｉＯに対しては、ＮＨ３、ブチルアミン、ヘキシルアミン及びトリメチルアミンのうちのいずれも吸着しやすい。これはアミン及びアンモニアの吸着サイトがＯ原子であるためである。 FIG. 11 is a bar graph showing the results of this evaluation test 2. The vertical axis of the graph shows the adsorption energy (unit: eV), and the lower the adsorption energy, the easier it is to adsorb. As shown in FIG. 11, it is difficult to adsorb any of NH 3 , butylamine, hexylamine and trimethylamine to Si, SiC and SiN. However , NH 3 , butylamine, hexylamine and trimethylamine are all easily adsorbed on SiO 2 CN and SiO. This is because the adsorption sites of amines and ammonia are O atoms.
この評価試験２の結果からは、Ｓｉ膜、酸化シリコン膜及びＳｉＯＣＮ膜についてのアミンの吸着性の差違を利用し、実施形態で述べたように酸化シリコン膜及びＳｉＯＣＮ膜を保護する一方で、Ｓｉ膜の選択的なエッチングが可能であることが推定できる。また、ＳｉＯＣＮ膜の孔壁にアミンを吸着させて、孔部を封止可能であることが推定できる。 From the results of this evaluation test 2, the difference in the adsorptivity of amines between the Si film, the silicon oxide film and the SiOCN film is utilized to protect the silicon oxide film and the SiOCN film as described in the embodiment, while Si. It can be estimated that selective etching of the film is possible. Further, it can be estimated that the pores can be sealed by adsorbing amines on the pore walls of the SiOCN film.
・評価試験３
評価試験３として、異なる種類の膜を各々の表面に備えた基板にブチルアミンガスを供給した。そしてガスクロマトグラフ質量分析計（ＧＣ－ＭＳ）により、各膜におけるブチルアミンの吸着量を測定した。 ・ Evaluation test 3
As evaluation test 3, butylamine gas was supplied to a substrate having different types of films on each surface. Then, the amount of butylamine adsorbed on each film was measured by a gas chromatograph mass spectrometer (GC-MS).
図１２はこの評価試験３の結果を示している。図に示すようにポリシリコン（Ｐｏｌｙ-Ｓｉ）膜及びアモルファスシリコン（α－Ｓｉ）膜における吸着量は略０ｎｇ／ｃｍ２である。そして、酸化シリコン膜における吸着量は概ね０．１０ｎｇ／ｃｍ２であり、ＳｉＯＣＮ膜における吸着量は概ね０．２７ｎｇ／ｃｍ２である。従って、アミンの吸着性は、Ｓｉ膜（ポリシリコン膜及びアモルファスシリコン膜）よりも酸素を含有するＳｉ膜（酸化シリコン膜及びＳｉＯＣＮ）膜の方が大きいことが示された。それ故に、この評価試験３の結果からは評価試験２の結果と同じく、アミンの吸着性の違いを利用して実施形態で示したように、Ｓｉ膜の選択的なエッチングが可能であることが推定される。 FIG. 12 shows the result of this evaluation test 3. As shown in the figure, the adsorption amount of the polysilicon (Poly-Si) film and the amorphous silicon (α-Si) film is approximately 0 ng / cm 2 . The adsorption amount on the silicon oxide film is approximately 0.10 ng / cm 2 , and the adsorption amount on the SiOCN film is approximately 0.27 ng / cm 2 . Therefore, it was shown that the adsorbability of amine is larger in the Si film (silicon oxide film and SiOCN) containing oxygen than in the Si film (polysilicon film and amorphous silicon film). Therefore, from the result of the evaluation test 3, as in the result of the evaluation test 2, it is possible to selectively etch the Si film as shown in the embodiment by utilizing the difference in the adsorptivity of amines. Presumed.
Ｗ　　　　　　ウエハ
１４　　　　　ポリシリコン膜
２１　　　　　アミン
２２　　　　　フッ素ガス

 
  W Wafer 14 polysilicon film 21 amine 22 fluorine gas

Claims (11)

  1. 　表面にシリコン膜が形成された基板にフッ素ガスとアミンガスとを供給して、当該シリコン膜をエッチングする工程を含むエッチング方法。 An etching method that includes a step of supplying fluorine gas and amine gas to a substrate having a silicon film formed on the surface and etching the silicon film.
  2. 　前記シリコン膜をエッチングする工程は、前記０℃～１５０℃の前記基板に、前記フッ素ガスと前記アミンガスとを供給する工程を含む請求項１記載のエッチング方法。 The etching method according to claim 1, wherein the step of etching the silicon film includes a step of supplying the fluorine gas and the amine gas to the substrate at 0 ° C. to 150 ° C.
  3. 前記シリコン膜をエッチングする工程は、前記基板を収納する処理容器内の圧力を、１３．３Ｐａ～６６６．５Ｐａとして、
    当該処理容器内に前記フッ素ガスと前記アミンガスとを供給する工程を含む請求項１記載のエッチング方法。     In the step of etching the silicon film, the pressure in the processing container for accommodating the substrate is set to 13.3 Pa to 666.5 Pa.
    The etching method according to claim 1, further comprising a step of supplying the fluorine gas and the amine gas into the processing container.
  4. 前記フッ素ガスとアミンガスとは、前記シリコン膜及び酸素を含有するシリコン膜が表面に形成された前記基板に供給され、前記シリコン膜をエッチングする工程は、前記シリコン膜及び前記酸素を含有するシリコン膜のうち、前記シリコン膜を選択的にエッチングする工程を含む請求項１記載のエッチング方法。 The fluorine gas and the amine gas are supplied to the substrate on which the silicon film and the silicon film containing oxygen are formed on the surface, and the step of etching the silicon film is the silicon film and the silicon film containing oxygen. The etching method according to claim 1, which comprises a step of selectively etching the silicon film.
  5. 　前記基板において前記シリコン膜、第１の膜、前記フッ素ガスに対して被エッチング性を有する第２の膜であるシリコン含有膜がこの順に隣り合って設けられ、
    前記１の膜及び前記第２の膜は前記酸素を含有するシリコン膜であり、前記第１の膜には前記シリコン膜と前記第２の膜とに開口する孔部が設けられ、
    前記シリコン膜をエッチングする工程は、
    前記第１の膜の孔部を形成する孔壁にアミンを吸着させる工程と、
    前記孔壁にアミンが吸着した基板に、前記フッ素ガスを供給する工程と、
    を備える請求項１記載のエッチング方法。     In the substrate, the silicon film, the first film, and the silicon-containing film, which is the second film having etching resistance to the fluorine gas, are provided next to each other in this order.
    The first film and the second film are silicon films containing oxygen, and the first film is provided with holes that open into the silicon film and the second film.
    The step of etching the silicon film is
    A step of adsorbing an amine on the pore wall forming the pore portion of the first film, and
    The step of supplying the fluorine gas to the substrate on which amine is adsorbed on the pore wall, and
    The etching method according to claim 1.
  6. 前記第１の膜は多孔質膜である請求項５記載のエッチング方法。 The etching method according to claim 5, wherein the first film is a porous film.
  7. 前記アミンガスを供給する工程と前記フッ素ガスを供給する工程とを、この順に複数回繰り返す繰り返し工程を含む請求項１記載のエッチング方法。 The etching method according to claim 1, wherein the step of supplying the amine gas and the step of supplying the fluorine gas are repeated a plurality of times in this order.
  8. 前記アミンガスを供給する期間と前記フッ素ガスを供給する期間との間、前記基板の周囲を排気する工程を含む請求項１記載のエッチング方法。 The etching method according to claim 1, further comprising a step of exhausting the periphery of the substrate between the period of supplying the amine gas and the period of supplying the fluorine gas.
  9. 　前記基板への前記フッ素ガスの供給と前記基板への前記アミンガスの供給とは、同時に行われる請求項１記載のエッチング方法。 The etching method according to claim 1, wherein the supply of the fluorine gas to the substrate and the supply of the amine gas to the substrate are performed at the same time.
  10. 　前記シリコン膜をエッチングする工程を行った後、前記基板からアミンを除去するために、前記基板を加熱する加熱工程を含む請求項１記載のエッチング方法。 The etching method according to claim 1, further comprising a heating step of heating the substrate in order to remove amine from the substrate after performing the step of etching the silicon film.
  11. 　処理容器と、
    　前記処理容器内に設けられ、表面にシリコン膜が形成された基板を載置するステージと、
    　前記シリコン膜をエッチングするために、前記処理容器内にアミンガスとフッ素ガスとを供給するガス供給部と、
    を含むエッチング装置。
     

          Processing container and
    A stage on which a substrate provided in the processing container and having a silicon film formed on the surface is placed, and
    A gas supply unit that supplies amine gas and fluorine gas into the processing container for etching the silicon film, and
    Etching equipment including.
PCT/JP2021/011215 2020-03-30 2021-03-18 Etching method and etching device WO2021200240A1 (en)

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Publication number Priority date Publication date Assignee Title
JP2019121784A (en) * 2017-12-27 2019-07-22 東京エレクトロン株式会社 Etching method and etching apparatus
JP2019196545A (en) * 2018-05-11 2019-11-14 ウォニク アイピーエス カンパニー リミテッドＷｏｎｉｋ Ｉｐｓ Ｃｏ．，Ｌｔｄ． Thin film formation method

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019121784A (en) * 2017-12-27 2019-07-22 東京エレクトロン株式会社 Etching method and etching apparatus
JP2019196545A (en) * 2018-05-11 2019-11-14 ウォニク アイピーエス カンパニー リミテッドＷｏｎｉｋ Ｉｐｓ Ｃｏ．，Ｌｔｄ． Thin film formation method

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