Method of operating film forming apparatus and film forming apparatus

Abstract

To provide a technique capable of removing a nickel-containing film deposited in a processing container.SOLUTION: Provided is a method for operating a film forming apparatus, including: (a) supplying a silicon-containing gas into a processing vessel to coat the inside of the processing vessel with an amorphous silicon film; (b) after the step (a), supplying a nickel source gas into the processing vessel to form a nickel-containing film; and (c) after the step (b), supplying a halogen-containing gas into the processing vessel to clean the inside of the processing vessel.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for operating a film formation apparatus and a film formation apparatus. [Background technology]

[0002] A technique is known in which an amorphous silicon film is modified into a polycrystalline silicon film by adsorbing nickel particles onto the surface of the amorphous silicon film and then annealing the film (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-60908 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique capable of removing nickel-containing films deposited inside a processing vessel. [Means for solving the problem]

[0005] A method of operating a film forming apparatus according to one aspect of the present disclosure includes: (a) supplying a silicon-containing gas into a processing vessel to coat the interior of the processing vessel with an amorphous silicon film; (b) after the step (a), supplying a nickel source gas into the processing vessel to form a nickel-containing film; and (c) after the step (b), supplying a halogen-containing gas into the processing vessel to clean the interior of the processing vessel. [Effects of the Invention]

[0006] According to the present disclosure, a nickel-containing film deposited inside a processing vessel can be removed. [Brief explanation of the drawings]

[0007] [Figure 1]1 is a cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 2] 4 is a flowchart illustrating a method for operating the film forming apparatus according to the embodiment. [Figure 3] FIG. 10 is a diagram showing an example of nickel concentration and carbon concentration before and after cleaning. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding reference numerals are used to designate the same or corresponding members or components, and redundant descriptions will be omitted.

[0009] [Film forming equipment] A film forming apparatus 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing the film forming apparatus 1 according to an embodiment.

[0010] The film forming apparatus 1 includes a processing chamber 10, a gas supply unit 30, an exhaust unit 40, a heating unit 50, and a control unit 90.

[0011] The processing vessel 10 has a double-tube structure consisting of a cylindrical inner tube 11 and a ceiling-equipped outer tube 12 concentrically placed outside the inner tube 11. The inner tube 11 and the outer tube 12 are made of, for example, quartz. The processing vessel 10 is configured to be able to accommodate a boat 16.

[0012] A storage section 13 is formed on one side of the inner pipe 11 along its longitudinal direction (vertical direction). The storage section 13 is an area within a protrusion 14 formed by protruding part of the side wall of the inner pipe 11 outward. The storage section 13 stores supply pipes 31a and 32a, which will be described later.

[0013] The lower end of the processing vessel 10 is supported by a cylindrical manifold 17 made of, for example, stainless steel. A flange 18 is formed at the upper end of the manifold 17. The flange 18 supports the lower end of the outer tube 12. A seal member 19, such as an O-ring, is provided between the flange 18 and the lower end of the outer tube 12.

[0014] An annular support member 20 is provided on the inner wall of the upper part of the manifold 17. The support member 20 supports the lower end of the inner tube 11. An exhaust port 21 is provided on the side wall of the upper part of the manifold 17 above the support member 20. A lid member 22 is airtightly attached to the opening at the lower end of the manifold 17 via a sealing member 23 such as an O-ring. The lid member 22 is made of, for example, stainless steel.

[0015] A rotating shaft 25 is provided through the center of the lid 22 via a magnetic fluid seal 24. The lower end of the rotating shaft 25 is rotatably supported by an arm 26A of an elevating mechanism 26 consisting of a boat elevator. A rotating plate 27 is provided at the upper end of the rotating shaft 25. The boat 16 is placed on the rotating plate 27 via a quartz heat-insulating tube 28.

[0016] Boat 16 holds a plurality of (e.g., 25 to 200) substrates W substantially horizontally with vertical spacing between them. The substrates W are, for example, semiconductor wafers. Boat 16 rotates integrally with rotation shaft 25. Boat 16 moves up and down integrally with lid 22 as arm 26A moves up and down, and is inserted into and removed from processing vessel 10.

[0017] The gas supply unit 30 is configured to be able to introduce various gases into the inner tube 11. The gas supply unit 30 includes a silicon raw material supply unit 31 and a nickel raw material supply unit 32.

[0018] The silicon source supply unit 31 includes a supply pipe 31a inside the processing vessel 10 and a supply path 31b outside the processing vessel 10. A silicon source 31c, a mass flow controller 31d, and an on-off valve 31e are installed on the supply path 31b, in this order from upstream to downstream in the gas flow direction. The on-off valve 31e controls the supply timing of the silicon-containing gas from the silicon source 31c, and the mass flow controller 31d adjusts the flow rate to a predetermined value. The silicon-containing gas flows from the supply path 31b into the supply pipe 31a and is then discharged from the supply pipe 31a into the processing vessel 10.

[0019] The nickel raw material supply unit 32 includes a supply pipe 32a inside the processing vessel 10 and a supply path 32b outside the processing vessel 10. A raw material tank 32c, a control valve 32d, and an on-off valve 32e are provided on the supply path 32b, in this order from upstream to downstream in the gas flow direction. The raw material tank 32c contains the nickel raw material. The nickel raw material is a raw material that is liquid at room temperature or a raw material that is solid at room temperature. A heater 32f is provided around the raw material tank 32c. The heater 32f heats the nickel raw material in the raw material tank 32c. As a result, the liquid nickel raw material is vaporized or the solid nickel raw material is sublimated, generating a nickel raw material gas.

[0020] The nickel source material supply unit 32 has a carrier gas pipe 32g inserted into the source material tank 32c from above. The carrier gas pipe 32g is provided with a carrier gas source 32h, an on-off valve 32i, and an adjustment valve 32j, in this order from upstream to downstream in the gas flow direction. Thus, the carrier gas from the carrier gas source 32h is supplied into the source material tank 32c with the supply timing controlled by the on-off valve 32i and the flow rate adjusted to a predetermined value by the adjustment valve 32j. The carrier gas, together with the nickel source material gas in the source material tank 32c, is supplied into the supply pipe 32a from the supply path 32b with the supply timing controlled by the on-off valve 32e and the flow rate adjusted to a predetermined value by the adjustment valve 32d. The nickel source material gas and carrier gas that have flowed into the supply pipe 32a are discharged into the processing vessel 10 from the supply pipe 32a.

[0021] A bypass path 32k may be provided that connects the upstream side of the on-off valve 32i in the carrier gas pipe 32g to the downstream side of the on-off valve 32e in the supply path 32b. A bypass valve 32l may be provided in the bypass path 32k.

[0022] The supply pipes 31a, 32a are fixed to the manifold 17. The supply pipes 31a, 32a are made of, for example, quartz. The supply pipes 31a, 32a extend linearly in the vertical direction near the inner pipe 11, and then bend in an L-shape within the manifold 17 and extend horizontally, thereby penetrating the manifold 17. The supply pipes 31a, 32a are arranged side by side along the circumferential direction of the inner pipe 11 and are formed at the same height.

[0023] A plurality of gas holes 31p, 32p are provided in the supply pipes 31a, 32a at portions thereof located within the inner pipe 11. The gas holes 31p, 32p are formed at predetermined intervals along the extension direction of the respective supply pipes 31a, 32a. The gas holes 31p, 32p discharge gas in the horizontal direction. The interval between the gas holes 31p, 32p is set to be the same as the interval between the substrates W held in the boat 16, for example. The height positions of the gas holes 31p, 32p are set at the midpoint between the vertically adjacent substrates W. In this case, the gas holes 31p, 32p can efficiently supply gas to the opposing surfaces of the adjacent substrates W.

[0024] The gas supply unit 30 may mix multiple types of gases and discharge the mixed gas from one supply pipe. For example, the supply pipes 31a and 32a may be configured to be able to discharge an inert gas. The supply pipes 31a and 32a may have different shapes and arrangements. The gas supply unit 30 may further include a supply pipe that supplies another gas in addition to the silicon-containing gas and the nickel raw material gas.

[0025] The exhaust unit 40 includes an exhaust passage 41, a pressure adjustment valve 42, and a vacuum pump 43. The exhaust passage 41 is connected to the exhaust port 21. The pressure adjustment valve 42 and the vacuum pump 43 are provided midway along the exhaust passage 41. The vacuum pump 43 is provided downstream of the pressure adjustment valve 42 in the gas flow direction. The exhaust flow rate of the gas inside the processing chamber 10 is controlled by the pressure adjustment valve 42, and the gas is discharged to the outside of the processing chamber 10 by the vacuum pump 43.

[0026] The heating part 50 has a cylindrical shape and is provided around the outer tube 12. The heating part 50 heats each substrate W in the processing chamber 10. The heating part 50 includes, for example, a heater.

[0027] The control unit 90 is an electronic circuit such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), etc. The control unit 90 executes various control operations described in this specification by executing instruction codes stored in a memory or by being a circuit designed for a specific application.

[0028] [Method of operating the film forming apparatus] A method for operating the film forming apparatus 1 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is a flowchart showing the method for operating the film forming apparatus 1 according to the embodiment. The method for operating the film forming apparatus 1 shown in Fig. 2 is performed under the control of a control unit 90.

[0029] As shown in FIG. 2, the method of operating the film forming apparatus 1 includes a coating step S1, a film forming step S2, a determining step S3, and a cleaning step S4.

[0030] The coating step S1 includes supplying a silicon-containing gas into the processing vessel 10 to coat the inside of the processing vessel 10 with an amorphous silicon film. The inside of the processing vessel 10 includes, for example, the inner wall surface of the processing vessel 10 and the surface of the boat 16. The silicon-containing gas is, for example, diisopropylaminosilane (DIPAS), disilane, monosilane, or a combination thereof. The coating step S1 is performed, for example, in a state where the boat 16 holding a plurality of dummy substrates Wd is accommodated in the processing vessel 10. The coating step S1 may also be performed in a state where the boat 16 is not accommodated in the processing vessel 10.

[0031] In one embodiment, first, the lifting mechanism 26 loads the boat 16 holding a plurality of dummy substrates Wd into the processing vessel 10. Next, the lid 22 airtightly closes the opening at the bottom of the processing vessel 10. Next, the exhaust unit 40 reduces the pressure inside the processing vessel 10 to a predetermined value, and the heating unit 50 adjusts the temperature inside the processing vessel 10 to a predetermined value. Next, the gas supply unit 30 supplies a silicon-containing gas into the processing vessel 10 to coat the inside of the processing vessel 10 with an amorphous silicon film, for example, by chemical vapor deposition (CVD). After the inside of the processing vessel 10 is coated with an amorphous silicon film having a predetermined thickness, the gas supply unit 30 stops supplying the silicon-containing gas into the processing vessel 10. The predetermined film thickness may be 50 nm to 150 nm, for example, 100 nm. The gas supply unit 30 may stop supplying the silicon-containing gas into the processing vessel 10 after a predetermined time has elapsed since the supply of the silicon-containing gas into the processing vessel 10 started. The predetermined time may be the time required for the interior of the processing vessel 10 to be coated with an amorphous silicon film having a predetermined thickness, and may be determined through a preliminary experiment or the like. Next, the control unit 90 increases the pressure inside the processing vessel 10 to atmospheric pressure and decreases the temperature inside the processing vessel 10 to an unloading temperature. Next, the lifting mechanism 26 unloads the boat 16 holding the multiple dummy substrates Wd from the processing vessel 10.

[0032] The film-forming process S2 is performed after the coating process S1. The film-forming process S2 includes supplying a nickel source gas into the processing vessel 10 to form a nickel-containing film. The nickel source gas can be generated, for example, by vaporizing a liquid nickel source. Examples of the liquid nickel source include (EtCp)2Ni[Ni(C2H5C5H4)2], NiPF3[Ni(PF3)4], CpAllylNi[(C3H5)(C5H5)Ni], or Ni(CO)4. The nickel source gas can be generated, for example, by sublimating a solid nickel source. Examples of the solid nickel source include (MeCp)2Ni[Ni(CH3C5H4)2]. The film-forming process S2 is performed, for example, with a boat 16 holding multiple product substrates Wp housed in the processing vessel 10. In the film forming step S2, a nickel-containing film is formed on the plurality of product substrates Wp, and the nickel-containing film is deposited on the amorphous silicon film that coats the inside of the processing chamber 10.

[0033] In one embodiment, first, the lifting mechanism 26 loads the boat 16 holding multiple product substrates Wp into the processing vessel 10. Next, the lid 22 airtightly closes the opening at the bottom of the processing vessel 10. Next, the exhaust unit 40 reduces the pressure inside the processing vessel 10 to a predetermined value, and the heating unit 50 adjusts the temperature inside the processing vessel 10 to a predetermined value. Next, the gas supply unit 30 supplies a nickel source gas into the processing vessel 10, and a nickel-containing film is formed on the product substrates Wp by, for example, chemical vapor deposition. At this time, the nickel-containing film is also deposited on the amorphous silicon film coating the inside of the processing vessel 10. When the nickel-containing film is deposited on the amorphous silicon film, the amorphous silicon film and the nickel source gas react to form nickel silicide (NixSiy, where x>0, y>0) at the interface between the amorphous silicon film and the nickel-containing film. After a nickel-containing film having a target thickness is formed on the product substrates Wp, the gas supply unit 30 stops supplying the nickel source gas into the processing vessel 10. The gas supply unit 30 may stop supplying the nickel source gas into the processing vessel 10 after a predetermined time has elapsed since the supply of the nickel source gas into the processing vessel 10 started. The predetermined time may be the time required for a nickel-containing film having a target thickness to be formed on the product substrates Wp, and may be determined through a preliminary experiment or the like. Next, the control unit 90 increases the pressure inside the processing vessel 10 to atmospheric pressure and decreases the temperature inside the processing vessel 10 to an unloading temperature. Next, the lifting mechanism 26 unloads the boat 16 holding the multiple product substrates Wp from the processing vessel 10.

[0034] The determination step S3 is performed after the film-forming step S2. In the determination step S3, it is determined whether the film-forming step S2 has been performed a set number of times. If the number of times has reached the set number of times (YES in the determination step S3), the process proceeds to the cleaning step S4. If the number of times has not reached the set number of times (NO in the determination step S3), the film-forming step S2 is performed again. That is, the film-forming step S2 is repeated until the number of times has reached the set number of times. When the film-forming step S2 is repeatedly performed, the thickness of the nickel-containing film deposited in the processing vessel 10 increases. If the thickness of the nickel-containing film deposited in the processing vessel 10 exceeds a threshold value, the nickel-containing film peels off and particles are generated. Therefore, the set number of times is set so that the thickness of the nickel-containing film does not exceed the threshold value. The set number of times may be one time, two times, or more.

[0035] The cleaning step S4 is performed after the determining step S3. The cleaning step S4 includes supplying a halogen-containing gas into the processing vessel 10 to clean the inside of the processing vessel 10. The halogen-containing gas is, for example, fluorine (F2) gas, chlorine (Cl2) gas, chlorine trifluoride (ClF3) gas, nitrogen trifluoride (NF3) gas, hydrogen fluoride (HF) gas, or a combination thereof.

[0036] In one embodiment, first, the lifting mechanism 26 loads the boat 16, which does not hold any substrates W, into the processing vessel 10. Next, the lid 22 airtightly closes the opening at the bottom of the processing vessel 10. Next, the exhaust unit 40 depressurizes the processing vessel 10 to a predetermined pressure, and the heating unit 50 adjusts the processing vessel 10 to a predetermined temperature. Next, the gas supply unit 30 supplies a halogen-containing gas into the processing vessel 10 to clean the processing vessel 10. At this time, nickel silicide is formed at the interface between the amorphous silicon film and the nickel-containing film, and therefore, the nickel silicide reacts with the halogen-containing gas to cause etching. During this process, the nickel-containing film deposited in the processing vessel 10 is removed along with the nickel silicide. Therefore, the nickel-containing film deposited in the processing vessel 10 can be easily removed. On the other hand, if the processing vessel 10 is covered with a nickel-containing film, etching of the nickel-containing film is likely to remain. After the nickel-containing film deposited in the processing vessel 10 is removed, the gas supply unit 30 stops supplying the halogen-containing gas into the processing vessel 10. Whether the nickel-containing film deposited in the processing vessel 10 has been removed is determined by an endpoint monitor, such as a plasma emission spectrometry endpoint monitor. The gas supply unit 30 may stop supplying the halogen-containing gas into the processing vessel 10 after a predetermined time has elapsed since the supply of the halogen-containing gas into the processing vessel 10 started. The predetermined time may be the time required to remove the nickel-containing film deposited in the processing vessel 10 and may be determined through a preliminary experiment or the like. Next, the control unit 90 increases the pressure inside the processing vessel 10 to atmospheric pressure and decreases the temperature inside the processing vessel 10 to an unloading temperature. Next, the lifting mechanism 26 unloads the boat 16, which does not hold the substrates W, from the processing vessel 10.

[0037] This completes the method for operating the film forming apparatus 1 shown in Fig. 2. The method for operating the film forming apparatus 1 shown in Fig. 2 may be performed repeatedly.

[0038] As described above, according to the method of operating the film forming apparatus 1 according to the embodiment, after the interior of the processing vessel 10 is coated with an amorphous silicon film, a nickel-containing film is formed in the processing vessel 10, and then the interior of the processing vessel 10 is cleaned using a halogen-containing gas. In this case, nickel silicide is formed at the interface between the amorphous silicon film and the nickel-containing film in the processing vessel 10, and therefore the nickel silicide reacts with the halogen-containing gas to cause etching. At this time, the nickel-containing film deposited in the processing vessel 10 is removed together with the nickel silicide. Therefore, the nickel-containing film deposited in the processing vessel 10 can be easily removed.

[0039] In the above embodiment, the film-forming step S2 is performed after the coating step S1. However, this is not limiting. For example, a second coating step may be performed between the coating step S1 and the film-forming step S2. The second coating step involves supplying a nickel-containing gas into the processing vessel 10 when the dummy substrate Wd is present but no product substrate Wp is present in the processing vessel 10, and coating the amorphous silicon film deposited in the processing vessel 10 with the nickel-containing film. In this case, the processing vessel 10 is coated with the nickel-containing film when the first film-forming step S2 is performed. This allows the environment in the processing vessel 10 when the first film-forming step S2 is performed to be closer to the environment in the processing vessel 10 when the second or subsequent film-forming steps S2 are performed. This reduces the variation in the quality of the nickel-containing film formed on the product substrate Wp in the first film-forming step S2 and the nickel-containing film formed on the product substrate Wp in the second or subsequent film-forming steps S2. In other words, the reproducibility of the processing for the product substrate Wp is improved.

[0040] [Experimental results] In the experiment, instead of a processing vessel 10 whose inner wall surface was coated with an amorphous silicon film, a quartz chip whose surface was coated with an amorphous silicon film was used to form a nickel-containing film on the amorphous silicon film, and then it was confirmed whether the nickel-containing film could be removed using fluorine gas.

[0041] First, quartz chips whose surfaces were coated with an amorphous silicon film were prepared. The amorphous silicon film had a thickness of 50 nm. The prepared quartz chips were then placed under the boat 16, and the boat 16 was then loaded into the processing vessel 10. Then, with the boat 16 housed in the processing vessel 10, nickel source gas was supplied into the processing vessel 10 to form a nickel-containing film on the surface of the quartz chips. The quartz chips were then removed from the processing vessel 10, and the nickel and carbon concentrations of the removed quartz chips were measured using X-ray photoelectron spectroscopy (XPS). The quartz chips with the nickel-containing film formed thereon were then placed under the boat 16, and the boat 16 was then loaded into the processing vessel 10. Then, with the boat 16 housed in the processing vessel 10, fluorine gas was supplied into the processing vessel 10 to clean the interior of the processing vessel 10. Fluorine gas is an example of a halogen-containing gas. Subsequently, the quartz chip was carried out from the processing vessel 10, and the nickel concentration and carbon concentration of the carried-out quartz chip were measured by X-ray photoelectron spectroscopy.

[0042] FIG. 3 shows an example of the nickel concentration and carbon concentration before and after cleaning. As shown in FIG. 3, the nickel concentration of the quartz chip before cleaning was 0.4 at % and the carbon concentration was 14.8%. This is thought to be because a nickel-containing film was formed on the quartz chip before cleaning. In contrast, as shown in FIG. 3, the nickel concentration of the quartz chip after cleaning was 0 at % and the carbon concentration was 0.4%. This is thought to be because the nickel-containing film was removed from the quartz chip by cleaning. These results suggest that by coating the interior of the processing vessel 10 with an amorphous silicon film before forming a nickel-containing film in the processing vessel 10, the nickel-containing film can be easily removed using a fluorine-containing gas.

[0043] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0044] In the above embodiment, the film forming apparatus is a batch type apparatus that processes multiple substrates at once, but the present disclosure is not limited to this. For example, the film forming apparatus may be a single-wafer type apparatus that processes substrates one by one. [Explanation of symbols]

[0045] S1 Coating process S2 Film formation process S4 Cleaning process

Claims

1. (a) supplying a silicon-containing gas into a processing vessel to coat the inside of the processing vessel with an amorphous silicon film; (b) after the step (a), supplying a nickel source gas into the processing vessel to form a nickel-containing film; (c) after the step (b), supplying a halogen-containing gas into the processing vessel to clean the inside of the processing vessel; A method for operating a film forming apparatus comprising the steps of:

2. the step (b) includes reacting the amorphous silicon film with the nickel source gas to form nickel silicide; A method for operating the film forming apparatus according to claim 1 .

3. The step (b) is performed in a state where a product substrate is present in the processing container. A method for operating the film forming apparatus according to claim 1 .

4. The step (c) is performed in a state where no product substrate is present in the processing chamber. A method for operating the film forming apparatus according to claim 1 .

5. The step (c) is carried out after repeating the step (b) two or more times. A method for operating the film forming apparatus according to claim 1 .

6. (d) between the step (a) and the step (b), a step of coating the amorphous silicon film coating the inside of the processing vessel with the nickel-containing film in a state where no product substrate is present in the processing vessel; A method for operating the film forming apparatus according to claim 1 .

7. The halogen-containing gas is fluorine gas. A method for operating the film forming apparatus according to claim 1 .

8. The nickel source gas is generated by vaporizing a liquid nickel source or sublimating a solid nickel source. A method for operating the film forming apparatus according to claim 1 .

9. The nickel raw material is Ni(C ２ H ５ C ５ H ４ ) ２ ], Ni(PF ３ ) ４ , (C ３ H ５ ) (C ５ H ５ )Ni, Ni(CO) ４ , or Ni(CH ３ C ５ H ４ ) ２ That is, The method for operating the film forming apparatus according to claim 8 .

10. A processing vessel; a gas supply unit for supplying a silicon-containing gas, a nickel source gas, and a halogen-containing gas into the processing chamber; A control unit; Equipped with The control unit (a) supplying the silicon-containing gas into the processing vessel to coat the inside of the processing vessel with an amorphous silicon film; (b) after the step (a), supplying the nickel source gas into the processing vessel to form a nickel-containing film; (c) after the step (b), supplying the halogen-containing gas into the processing vessel to clean the inside of the processing vessel; configured to: Film deposition equipment.

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