Film forming apparatus and cleaning method

Abstract

The present disclosure provides a film forming apparatus and a cleaning method capable of removing a reaction product deposited inside an exhaust device. A film forming apparatus according to one embodiment of the present disclosure performs film forming of a film containing silicon and oxygen, and is provided with: a processing container inside which the film is formed; a supply flow path for supplying a cleaning gas to the inside of the processing container; an exhaust flow path for exhausting the inside of the processing container; and a moisture introduction unit that introduces moisture into the exhaust flow path.

Description

Technical Field

[0001] This disclosure relates to a film-forming apparatus and a cleaning method. Background Technology

[0002] A technique is known of introducing clean gas into an exhaust pipe connected to a reaction chamber to clean the exhaust pipe (see, for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-107243 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] This disclosure provides a technique for removing reaction products deposited inside an exhaust device.

[0008] Solution for solving the problem

[0009] One aspect of the film-forming apparatus disclosed herein is for forming a film comprising silicon and oxygen. The film-forming apparatus includes: a processing container, wherein the film forming is performed inside the processing container; a supply flow path for supplying a cleaning gas to the interior of the processing container; an exhaust flow path for venting the interior of the processing container; and a moisture inlet for introducing moisture into the exhaust flow path.

[0010] The effects of the invention

[0011] According to this disclosure, it is possible to remove reaction products deposited inside the exhaust device. Attached Figure Description

[0012] Figure 1 This is a diagram illustrating the film-forming apparatus according to the embodiment.

[0013] Figure 2 This is a diagram illustrating an example of film-forming treatment.

[0014] Figure 3 This is a diagram illustrating an example of container cleaning procedures.

[0015] Figure 4 This is a flowchart illustrating an example of pump cleaning procedures.

[0016] Figure 5 Figure (1) shows an example of pump cleaning treatment.

[0017] Figure 6 Figure (2) shows an example of pump cleaning treatment.

[0018] Figure 7 This is a diagram illustrating another example of pump cleaning procedures.

[0019] Figure 8 This is a graph illustrating an example of the relationship between moisture concentration and etching amount. Detailed Implementation

[0020] The non-limiting embodiments illustrated in this disclosure will now be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding components or parts are labeled with the same or corresponding reference numerals, and repeated descriptions are omitted.

[0021] [Film-forming device]

[0022] Reference Figure 1 To illustrate the film-forming apparatus 1 involved in the implementation method. Figure 1 This is a diagram showing the film-forming apparatus 1 according to the embodiment.

[0023] The film forming apparatus 1 includes a processing container 10, a gas supply unit 20, an exhaust unit 30, a moisture introduction unit 40, and a control unit 90.

[0024] The processing container 10 is a container with a processing space formed inside, capable of accommodating one or more substrates. Within the processing space, a film containing silicon and oxygen is formed on the substrate. The substrate is, for example, a semiconductor wafer. The film containing silicon and oxygen is, for example, a silicon oxide film.

[0025] The gas supply unit 20 has a first supply flow path 21, a second supply flow path 22, a third supply flow path 23 and a bypass flow path 24.

[0026] The first supply path 21 is connected to the processing container 10. In the first supply path 21, a silicon-containing gas supply source 21s and an on / off valve 21v are sequentially arranged from upstream to downstream in the gas flow direction. The on / off valve 21v is used to switch the flow of silicon-containing gas between open and closed states. When open, the on / off valve 21v allows the silicon-containing gas to flow downstream; when closed, it prevents the silicon-containing gas from flowing downstream. The first supply path 21 supplies the silicon-containing gas from the supply source 21s into the processing container 10. The on / off valve 21v controls the timing of the silicon-containing gas supply from the supply source 21s. A mass flow controller can also be installed in the first supply path 21.

[0027] The second supply path 22 is connected to the processing container 10. In the second supply path 22, from upstream to downstream in the gas flow direction, an oxidizing gas supply source 22s and an on / off valve 22v are sequentially arranged. The on / off valve 22v switches the flow of oxidizing gas between open and closed states. When open, the on / off valve 22v allows the oxidizing gas to flow downstream; when closed, it prevents the oxidizing gas from flowing downstream. The second supply path 22 is used to supply the oxidizing gas from the supply source 22s into the processing container 10. The on / off valve 22v controls the timing of the oxidizing gas supply from the supply source 22s. A mass flow controller can also be installed in the second supply path 22.

[0028] The third supply path 23 is connected to the processing container 10. In the third supply path 23, a hydrogen fluoride (HF) gas supply source 23s and an on / off valve 23v are sequentially arranged from upstream to downstream in the gas flow direction. The on / off valve 23v switches the flow of hydrogen fluoride gas between open and closed states. When open, the on / off valve 23v allows hydrogen fluoride gas to flow downstream; when closed, it prevents downstream flow. The third supply path 23 supplies hydrogen fluoride gas from the supply source 23s into the processing container 10. The on / off valve 23v controls the supply source 23s according to the timing of hydrogen fluoride gas supply. A mass flow controller can also be installed in the third supply path 23. Hydrogen fluoride gas is an example of a clean gas.

[0029] The bypass flow path 24 branches off from the middle of the third supply flow path 23 and merges with the exhaust flow path 31 midway through the exhaust flow path 31. The bypass flow path 24 branches off from the third supply flow path 23 at position P1 between the supply source 23s and the on / off valve 23v, and merges with the exhaust flow path 31 at position P2 between the on / off valve 31v and the exhaust device 31p. An on / off valve 24v is provided in the bypass flow path 24. The on / off valve 24v is a valve that switches the flow of hydrogen fluoride gas between open and closed states. When open, the on / off valve 24v allows hydrogen fluoride gas to flow downstream; when closed, it prevents downstream flow. The bypass flow path 24 is used to supply hydrogen fluoride gas from the supply source 23s to the exhaust flow path 31 without passing through the interior of the processing container 10. The on / off valve 24v controls the timing of the supply of hydrogen fluoride gas from the supply source 23s. A mass flow controller can also be provided in the bypass flow path 24.

[0030] The exhaust section 30 has an exhaust flow path 31. The exhaust flow path 31 is connected to the processing container 10. In the exhaust flow path 31, an on / off valve 31v and an exhaust device 31p are sequentially arranged from upstream to downstream in the gas flow direction. The on / off valve 31v switches the flow of gas through the exhaust flow path 31 between open and closed states. When open, the on / off valve 31v allows gas to flow downstream; when closed, it prevents gas from flowing downstream. The exhaust device 31p includes a vacuum pump. The vacuum pump is, for example, a combination of a dry pump and a mechanical booster pump. The exhaust flow path 31 exhausts the gas inside the processing container 10 through the exhaust device 31p. The timing of the gas exhaust from the processing container 10 is controlled by the on / off valve 31v.

[0031] The moisture inlet section 40 has a moisture inlet flow path 41. The moisture inlet flow path 41 is connected to the exhaust flow path 31 at a position P3, farther from the processing container 10 than the confluence point P2 of the bypass flow path 24 and the exhaust flow path 31. Alternatively, the moisture inlet flow path 41 may be connected to the exhaust flow path 31 at a position closer to the processing container 10 than the confluence point P2 of the bypass flow path 24 and the exhaust flow path 31. Moisture is introduced into the moisture inlet flow path 41. The moisture is, for example, water vapor generated by a water vapor generator. The moisture can also be atmospheric air. An on / off valve 41v and a backflow prevention valve 41c are sequentially arranged in the moisture inlet flow path 41 from upstream to downstream in the direction of moisture flow. The on / off valve 41v switches the flow of moisture through the moisture inlet flow path 41 between open and closed states. When open, the on / off valve 41v allows gas to flow downstream; when closed, it prevents gas from flowing downstream. Backflow prevention valve 41c prevents gas from flowing back from exhaust flow path 31 to water inlet flow path 41. Water inlet flow path 41 is used to introduce water into exhaust flow path 31. The timing of water supply is controlled by on / off valve 41v. A throttling orifice may also be provided in water inlet flow path 41.

[0032] The control unit 90 is an electronic circuit such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit). The control unit 90 executes various control actions described in this application specification by executing instruction codes stored in memory or by designing circuits for special purposes.

[0033] [Operation of the film-forming device]

[0034] The operation of the film-forming apparatus 1 according to the embodiment will be explained. The operation of the film-forming apparatus 1 shown below is performed automatically under the control of the control unit 90.

[0035] (Film-forming treatment)

[0036] Reference Figure 2 This will explain the operation of the film-forming device 1 when it is performing film-forming treatment. Figure 2 This is a diagram illustrating an example of film-forming treatment. In Figure 2 In the image, the arrows indicate the flow of gas.

[0037] like Figure 2 As shown, during the film formation process, the control unit 90 controls the on / off valves 21v, 22v, and 31v to be in the open state, and controls the on / off valves 23v, 24v, and 41v to be in the closed state. As a result, the silicon-containing gas from the supply source 21s is supplied to the interior of the processing container 10 via the first supply flow path 21, and the oxidizing gas from the supply source 22s is supplied to the interior of the processing container 10 via the second supply flow path 22. When the silicon-containing gas and the oxidizing gas are supplied to the interior of the processing container 10, a silicon oxide film is formed on the substrate.

[0038] During the film deposition process, a silicon oxide film is deposited not only on the surface of the substrate but also on the inner wall of the processing container 10 and on components inside the processing container 10. Silicon-containing gases and oxidizing gases that are not consumed inside the processing container 10 are exhausted by the exhaust device 31p via the exhaust flow path 31. The silicon-containing gases and oxidizing gases exhausted via the exhaust flow path 31 flow into the exhaust device 31p, thus depositing a silicon oxide film inside the exhaust device 31p as well. When film deposition on the substrate is repeated, the amount of silicon oxide film deposited inside the processing container 10 and inside the exhaust device 31p increases. Therefore, when film deposition is performed a predetermined number of times, the control unit 90 performs container cleaning to remove the silicon oxide film deposited inside the processing container 10 and pump cleaning to remove the silicon oxide film deposited inside the exhaust device 31p.

[0039] (Container cleaning)

[0040] Reference Figure 3 This will explain the operation of the film-forming device 1 when it is cleaning the container. Figure 3 This is a diagram illustrating an example of container cleaning procedures. Figure 3 In the image, the arrows indicate the flow of gas.

[0041] like Figure 3As shown, during container cleaning, the control unit 90 controls the on / off valves 23v and 31v to be in the open state, and controls the on / off valves 21v, 22v, 24v, and 41v to be in the closed state. As a result, hydrogen fluoride gas from the supply source 23s is supplied to the interior of the processing container 10 via the third supply path 23. When the hydrogen fluoride gas is supplied to the interior of the processing container 10, it reacts with the silicon oxide film deposited inside the processing container 10, and the silicon oxide film is removed.

[0042] (Pump cleaning)

[0043] Reference Figures 4 to 6 This will explain the operation of the film-forming device 1 when the pump is being cleaned. Figure 4 This is a flowchart illustrating an example of pump cleaning procedures. Figure 5 and Figure 6 This is a diagram illustrating an example of pump cleaning procedures. Figure 5 and Figure 6 In the diagram, arrows indicate gas flow. During pump cleaning, the process involves... Figure 4 The processing of steps S1 to S3 is shown.

[0044] In step S1, the control unit 90 controls the on / off valve 24v to the open state, and controls the on / off valves 21v, 22v, 23v, 31v, and 41v to the closed state (see reference). Figure 5 Therefore, the hydrogen fluoride gas supplied from source 23s flows into exhaust flow path 31 via bypass flow path 24 without passing through the interior of processing container 10, and reaches exhaust device 31p. In this case, hydrogen fluoride gas before being consumed by reacting with the silicon oxide film can be supplied to exhaust device 31p. Therefore, the hydrogen fluoride gas reacts with the silicon oxide film deposited inside exhaust device 31p, and the silicon oxide film is removed. At this time, hydrogen fluoride gas is not supplied to the interior of processing container 10, thus preventing excessive etching of the interior of processing container 10 by hydrogen fluoride gas.

[0045] In step S2, the control unit 90 determines whether the state of the exhaust device 31p is the desired state. The desired state is, for example, a state where the thickness of the silicon oxide film inside the exhaust device 31p is less than or equal to a desired thickness. For example, if the back pressure of the vacuum pump included in the exhaust device 31p is less than a threshold, the control unit 90 determines that the thickness of the silicon oxide film inside the exhaust device 31p is less than the desired thickness. Conversely, if the back pressure of the vacuum pump included in the exhaust device 31p is greater than the threshold, the control unit 90 determines that the thickness of the silicon oxide film inside the exhaust device 31p is not less than the desired thickness. For example, if the load of the vacuum pump included in the exhaust device 31p is less than a threshold, the control unit 90 determines that the thickness of the silicon oxide film inside the exhaust device 31p is less than the desired thickness. Conversely, if the load of the vacuum pump included in the exhaust device 31p is greater than the threshold, the control unit 90 determines that the thickness of the silicon oxide film inside the exhaust device 31p is not less than the desired thickness.

[0046] In step S2, if the exhaust device 31p is in the desired state (step S2: "Yes"), the process ends. In step S2, if the exhaust device 31p is not in the desired state (step S2: "No"), the process proceeds to step S3.

[0047] In step S3, the control unit 90 switches the on / off valve 24v from the open state to the closed state and switches the on / off valve 41v from the closed state to the open state (see reference). Figure 6 Therefore, the supply of hydrogen fluoride gas from the supply source 23s to the exhaust flow path 31 is stopped, and moisture is introduced into the exhaust flow path 31 from the moisture introduction flow path 41. The moisture introduced into the exhaust flow path 31 increases the moisture content of the silicon oxide film deposited inside the exhaust device 31p. After step S3, step S1 is performed again. When step S1 is performed after step S3, the hydrogen fluoride gas supplied to the exhaust device 31p reacts with the silicon oxide film deposited inside the exhaust device 31p, and the silicon oxide film is removed. The higher the moisture content, the easier it is for the reaction between the silicon oxide film and hydrogen fluoride gas, etc., to proceed. Therefore, in step S1 performed after step S3, the silicon oxide film is easily removed.

[0048] As explained above, the control unit 90 performs the following processes: introducing moisture from the moisture inlet 40 into the exhaust flow path 31 (step S3); and supplying hydrogen fluoride gas from the third supply flow path 23 into the exhaust flow path 31 (step S1). In this case, the moisture content of the silicon oxide film deposited inside the exhaust device 31p increases, and the reaction between the silicon oxide film and the hydrogen fluoride gas is more likely to proceed. Therefore, reaction products such as the silicon oxide film deposited inside the exhaust device 31p can be removed efficiently.

[0049] The control unit 90 does not simultaneously perform the process of introducing moisture from the moisture inlet 40 to the exhaust flow path 31 (step S3) and the process of supplying hydrogen fluoride gas from the third supply flow path 23 to the exhaust flow path 31 (step S1). In this case, moisture can be introduced into the exhaust device 31p in a way that prevents the moisture from reacting with the hydrogen fluoride gas. Therefore, it is easy to increase the moisture content of the silica film inside the exhaust device 31p.

[0050] The control unit 90 repeats these processes in the order of introducing moisture from the moisture inlet 40 to the exhaust flow path 31 (step S3) and supplying hydrogen fluoride gas from the third supply flow path 23 to the exhaust flow path 31 (step S1) until the exhaust device 31p reaches the desired state. In this case, the thickness of the silicon oxide film deposited inside the exhaust device 31p can be reduced to below the desired thickness.

[0051] Figure 7 This is another diagram illustrating pump cleaning procedures. (As shown) Figure 7 As shown, during the pump cleaning process, the control unit 90 can simultaneously perform the process of introducing water from the moisture inlet 40 into the exhaust flow path 31 (step S3) and the process of supplying hydrogen fluoride gas from the third supply flow path 23 into the exhaust flow path 31 (step S1). Specifically, the control unit 90 controls the on / off valves 24v and 41v to be in the open state, and controls the on / off valves 21v, 22v, 23v, and 31v to be in the closed state. As a result, the hydrogen fluoride gas from the supply source 23s flows into the exhaust flow path 31 and reaches the exhaust device 31p via the bypass flow path 24 without passing through the interior of the processing container 10, and moisture is introduced into the exhaust flow path 31 and reaches the exhaust device 31p from the moisture inlet flow path 41. In this case, it is preferable that the moisture inlet flow path 41 is connected to a position in the exhaust flow path 31 immediately before the exhaust device 31p. Therefore, even if hydrogen fluoride gas and moisture are supplied to the exhaust flow path 31 at the same time, moisture can be easily introduced into the exhaust device 31p in a manner that hardly reacts with hydrogen fluoride gas.

[0052] [Evaluation Results]

[0053] The effect of moisture content in the silicon oxide film on the etching amount of the silicon oxide film was evaluated. First, a substrate with film A and a substrate with film B formed were housed inside the processing container 10 of the film deposition apparatus 1. Hydrogen fluoride gas from the supply source 23s was supplied to the processing container 10 from the third supply flow path 23 to etch films A and B. Next, the etching amount of films A and B was measured. Film A had a moisture (H₂O) concentration of 1.0 × 10⁻⁶. 21 atoms / cm 3 The silicon dioxide film. Film B has a moisture concentration of 4.9 × 10⁻⁶.20 atoms / cm 3 Silica film.

[0054] Figure 8 This is a graph illustrating an example of the relationship between moisture concentration and etching amount. In Figure 8 In this context, the etching amount of film A is represented by a relative value when the etching amount of film B is set to 1. For example... Figure 8 As shown, the etching amount of film A is greater than that of film B. Based on this result, it can be said that when the moisture content of the silicon oxide film is high, the silicon oxide film is easily etched by hydrogen fluoride gas.

[0055] It should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. The above embodiments may also be omitted, substituted, and modified in various ways without departing from the appended claims and their spirit.

[0056] Explanation of reference numerals in the attached figures

[0057] 1: Film forming device; 10: Processing container; 23: Third supply flow path; 31: Exhaust flow path; 40: Moisture introduction section.

Claims

1. A film-forming apparatus for forming a film comprising silicon and oxygen, the film-forming apparatus comprising: A processing container, inside which the membrane is formed; A supply path for supplying cleaning gas to the interior of the processing container; An exhaust flow path for venting the interior of the processing container; and A moisture inlet section introduces moisture into the exhaust flow path.

2. The film-forming apparatus according to claim 1, wherein, It has a bypass flow path, which branches off from the middle of the supply flow path and merges with the exhaust flow path at the middle of the exhaust flow path.

3. The film-forming apparatus according to claim 2, wherein, The moisture inlet section has a moisture inlet flow path for introducing the moisture into the exhaust flow path. The moisture inlet path is connected to the exhaust path at a location farther from the processing container than the location where the bypass path and the exhaust path merge.

4. The film-forming apparatus according to claim 3, wherein, The water inlet section has a backflow prevention valve installed in the water inlet flow path.

5. The film-forming apparatus according to any one of claims 1 to 4, wherein, The film-forming device includes a control unit. The control unit performs the following processing: This allows the moisture to be introduced from the moisture inlet into the exhaust flow path; and This allows the clean gas to be supplied from the supply path to the exhaust path.

6. The film-forming apparatus according to claim 5, wherein, The control unit does not simultaneously perform the process of introducing the moisture and supplying the cleaning gas.

7. The film-forming apparatus according to claim 6, wherein, An exhaust device is provided in the exhaust flow path. The control unit repeats these processes in the order of introducing the moisture and supplying the clean gas until the exhaust device reaches the desired state.

8. The film-forming apparatus according to claim 5, wherein, The control unit simultaneously processes the introduction of moisture and the supply of clean gas.

9. The film-forming apparatus according to claim 5, wherein, It has a bypass flow path that branches off from the middle of the supply flow path and merges with the exhaust flow path at the middle of the exhaust flow path. The process of supplying the clean gas includes supplying the clean gas to the exhaust flow path via the bypass flow path instead of through the processing container.

10. The film-forming apparatus according to claim 1, wherein, The membrane is a silicon oxide membrane.

11. A cleaning method for cleaning a film-forming apparatus comprising a silicon and oxygen film, wherein, The film-forming apparatus includes: A processing container, inside which the membrane is formed; A supply path for supplying cleaning gas to the interior of the processing container; An exhaust flow path is provided for venting the interior of the processing container; as well as A moisture inlet section introduces moisture into the exhaust flow path. The cleaning method includes: The moisture is introduced from the moisture inlet into the exhaust flow path; as well as The clean gas is supplied from the supply path to the exhaust path.

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