Purge method and film deposition apparatus

Abstract

To provide a technique for improving the reduction effect of electric resistivity in a film formed by hydrogen gas and reducing surface roughness.SOLUTION: In a purge method in a film deposition apparatus including a substrate support part including a stage for supporting a processing substrate and an outer ring provided around the stage; and a gas supply part including a shower head provided to face the processing substrate and supplying processing gas and purge gas, when supplying and purging gas having mixed hydrogen as the purge gas from the gas supply part, an interval between the outer ring and an outer edge part of the shower head is 1 millimeter or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a purging method and a film forming apparatus. [Background technology]

[0002] Patent Document 1 discloses that the H2 gas supplied when purging the reaction gas has the function of lowering the resistivity of the TiN film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7033882 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for improving the effect of reducing the electrical resistivity of a film formed by hydrogen gas and reducing the surface roughness. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a purging method for a film formation apparatus including a substrate support unit having a stage for supporting a processing substrate and an outer ring provided around the stage, and a gas supply unit having a shower head provided opposite the processing substrate and supplying a processing gas and a purge gas, wherein when a gas mixed with hydrogen is supplied from the gas supply unit as the purge gas for purging, a distance between the outer ring and an outer edge of the shower head is 1 millimeter or less. Effect of the Invention

[0006] The present disclosure provides a technique for improving the effect of reducing the electrical resistivity of a film formed by hydrogen gas and reducing the surface roughness. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a film forming apparatus in which a purging method according to this embodiment is used. [Diagram 2] FIG. 2 is a flow diagram illustrating the purging method according to the first embodiment. [Diagram 3] FIG. 3 is a diagram illustrating the relationship between the distance and the electrical resistivity in the purging method according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating gas pressure. [Diagram 5] FIG. 5 is a diagram illustrating the relationship between the distance and the surface roughness in the purging method according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating the interval in the purging method according to the first embodiment. [Figure 7] FIG. 7 is a flow diagram illustrating a purging method according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0009] In addition, in the description of the specification and drawings of each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same or corresponding reference numerals to avoid redundant explanation. In addition, the scale of each part in the drawings may differ from the actual scale in order to facilitate understanding.

[0010] Purging method according to the first embodiment The purging method according to the first embodiment is a purging method for a film forming apparatus including a substrate support unit including a stage for supporting a processing substrate and an outer ring provided around the stage, and a gas supply unit including a shower head provided opposite to the processing substrate and supplying a processing gas and a purge gas. The purging method according to the first embodiment is a purging method in which the distance between the outer ring and the outer edge of the shower head is 1 millimeter or less when purging by supplying a gas mixed with hydrogen from the gas supply unit as a purge gas.

[0011] First, a film forming apparatus in which the purging method according to the present embodiment is used will be described. Fig. 1 is a diagram showing the overall configuration of a film forming apparatus 1, which is an example of a film forming apparatus in which the purging method according to the present embodiment is used.

[0012] The film forming apparatus 1 is a film forming apparatus that uses a so-called atomic layer deposition (ALD) method. For example, the film forming apparatus 1 supplies a source gas to a processing chamber under a vacuum atmosphere. Then, the film forming apparatus 1 adsorbs the source gas onto the surface of a processing substrate such as a semiconductor wafer. Next, the film forming apparatus 1 supplies a reactive gas. Then, the film forming apparatus 1 forms one or a few atomic layers by reacting the source gas with the reactive gas. The film forming apparatus 1 repeats the above-mentioned cycle to stack atomic layers and form a film on the processing substrate. The source gas and the reactive gas are collectively referred to as processing gas.

[0013] The film forming apparatus 1 includes a substrate support unit 10, a gas supply unit 20, a processing vessel unit 30, and a gas storage unit 40.

[0014] [Substrate support part 10] The substrate support portion 10 includes a stage 11, an outer ring 12, lift pins 13, a lift member 14, a support member 15, a lift plate 16, a bellows 17, and a lift mechanism 18.

[0015] (Stage 11) The stage 11 carries a wafer W, which is an example of a substrate to be processed. The wafer W is, for example, a semiconductor wafer. The stage 11 is made of, for example, aluminum nitride or quartz. The stage 11 has a flat, disk-like shape.

[0016] The stage 11 includes a heater 11a therein. The heater 11a is supplied with power from a power source 11b. The heater 11a is capable of heating the wafer W to a temperature of, for example, 430° C. by receiving power from the power source 11b.

[0017] The stage 11 may include an electrostatic chuck therein. The stage 11 electrostatically attracts and fixes the wafer W placed on the stage 11 by the electrostatic chuck.

[0018] (Outer ring 12) The outer ring 12 is provided around the stage 11. The outer ring 12 is made of, for example, aluminum nitride or quartz.

[0019] (Lift pin 13) The lift pins 13 lift the wafer W from the mounting surface of the stage 11 when the wafer W is loaded or unloaded. The substrate support portion 10 includes, for example, three lift pins 13. The number of lift pins 13 is not limited to three and may be determined as appropriate.

[0020] Lift pins 13 have flat heads and rod-shaped portions provided below the heads. When wafer W is placed on lift pins 13, the heads of lift pins 13 come into contact with the upper surface of stage 11 and are stopped there. The rod-shaped portions of lift pins 13 are provided so as to penetrate stage 11 and protrude from the bottom surface of stage 11. Lifting members 14, which will be described later, move up and down to raise and lower the lower ends of lift pins 13, thereby lifting and lowering lift pins 13.

[0021] (Lifting member 14) The lifting member 14 raises and lowers the lifting pins 13. The lifting member 14 is provided below the lifting pins 13. When the lifting member 14 rises, it comes into contact with the lower ends of the lifting pins 13. When the lifting member 14 rises further while in contact with the lower ends of the lifting pins 13, the lifting pins 13 rise, and the heads of the lifting pins 13 protrude from the mounting surface of the stage 11. When the lifting member 14 descends while the heads of the lifting pins 13 protrude, the lower ends of the lifting pins 13 descend. When the lower ends of the lifting pins 13 descend, the lifting pins 13 descend, and the heads of the lifting pins 13 come into contact with the mounting surface of the stage 11.

[0022] (Support member 15) The support member 15 connects between the stage 11 and the lift plate 16. The support member 15 penetrates the bottom of the processing vessel part 30, more specifically, the bottom of a lower vessel 31 which will be described later. The support member 15 is connected to the lift plate 16.

[0023] (Lifting plate 16) The lift plate 16 is raised and lowered by a lift mechanism 18. The lift plate 16 raises and lowers the support member 15. When the lift plate 16 raises and lowers the support member 15, the stage 11 rises and lowers.

[0024] (Bellows 17) The bellows 17 connects between the bottom of the processing vessel part 30, more specifically, the bottom of a lower vessel 31 (described later), and the lift plate 16. The bellows 17 ensures that the inside of the processing vessel part 30 is airtight.

[0025] (Lifting mechanism 18) The lifting mechanism 18 raises and lowers the lifting plate 16. When the lifting mechanism 18 raises and lowers the lifting plate 16, the stage 11 rises and lowers.

[0026] [Gas supply unit 20] The gas supply unit 20 supplies gas to the processing space. The gas supply unit 20 includes a support member 21 and a shower head 22.

[0027] (Support member 21) The support member 21 holds the shower head 22. In addition, the support member 21 covers and closes the upper side of the processing vessel part 30.

[0028] (Shower Head 22) The shower head 22 supplies a source gas, a reaction gas, and a purge gas into the processing space SP. The shower head 22 supplies the source gas, the reaction gas, and the purge gas introduced from the gas storage unit 40 through the gas supply port 20a of the gas supply unit 20 to the processing space SP.

[0029] The shower head 22 has a gas diffusion chamber 22a and a plurality of gas inlets 22b. The source gas, the reaction gas, and the purge gas supplied from the gas supply port 20a pass through the gas diffusion chamber 22a and are supplied to the processing space SP from the plurality of gas inlets 22b. The plurality of gas inlets 22b are provided in a central portion 22C near the center of the shower head 22.

[0030] The shower head 22 has an outer edge portion 22P that protrudes downward outside a central portion 22C where a plurality of gas inlets 22b are provided. The outer edge portion 22P is provided opposite the outer ring 12 of the substrate support 10.

[0031] A processing space SP is formed between the shower head 22 and the stage 11. Specifically, the processing space SP is a space surrounded by the lower surface of the central portion 22C, the inner surface of the outer edge portion 22P, and the upper surface of the stage 11.

[0032] [Processing vessel section 30] The processing vessel part 30 includes therein the substrate support part 10. The processing vessel part 30 includes a lower vessel 31, an upper vessel 32, and a connecting member 33.

[0033] (Lower container 31) The lower container 31 holds the substrate support 10. The lower container 31 has a cylindrical shape having a bottom surface portion that serves as a bottom plate. The bottom surface portion of the lower container 31 has a through hole through which the support member 15 passes. The lift plate 16 is attached to the bottom plate of the lower container 31 via a bellows 17.

[0034] A purge gas supply port 35a is provided on the bottom plate of the lower container 31. A purge gas such as nitrogen gas is supplied from a purge gas supply unit 35 through the purge gas supply port 35a.

[0035] (Upper container 32) The upper vessel 32 is provided above the lower vessel 31. An exhaust space SPe is formed between the upper vessel 32 and the outer side surface of the shower head 22. The exhaust mechanism 34 exhausts each of the source gas, the reaction gas, and the purge gas in the processing space SP through the exhaust space SPe.

[0036] (connecting member 33) The connecting member 33 mounts the support member 21 of the gas supply unit 20. By mounting the support member 21 on the connecting member 33, a sealed space is formed by the gas supply unit 20 and the processing vessel unit 30.

[0037] [Gas storage unit 40] The gas storage unit 40 stores the source gas, the reaction gas, and the purge gas, and also supplies the stored source gas, reaction gas, and purge gas to the gas supply unit 20.

[0038] The gas storage unit 40 includes a raw material gas storage unit 41A that stores a raw material gas, and a control valve 42A that controls the supply of the raw material gas from the raw material gas storage unit 41A to the gas supply unit 20. The gas storage unit 40 also includes a reactive gas storage unit 41B that stores a reactive gas, and a control valve 42B that controls the supply of the reactive gas from the reactive gas storage unit 41B to the gas supply unit 20. The gas storage unit 40 also includes a purge gas storage unit 41C that stores a purge gas, and a control valve 42C that controls the supply of the purge gas from the purge gas storage unit 41C to the gas supply unit 20.

[0039] The gas storage unit 40 supplies the source gas, the reaction gas, and the purge gas to the gas supply unit 20 via pipes 43.

[0040] Here, as an example, a case where a titanium nitride (TiN) film layer is formed on the processing substrate will be described. When the titanium nitride film is formed on the processing substrate, titanium chloride (TiCl4) gas is used as the raw material gas. The raw material gas storage unit 41A may store and supply a carrier gas for carrying the raw material gas, such as nitrogen gas or argon gas, together with the raw material gas. When titanium chloride (TiCl4) is used as the raw material gas when the titanium nitride film is formed on the processing substrate, ammonia (NH3) gas is used as the reactive gas. The reactive gas storage unit 41B may store and supply a carrier gas for carrying the reactive gas, such as nitrogen gas or argon gas, together with the reactive gas. Furthermore, when the titanium nitride film is formed on the processing substrate, a gas containing hydrogen (H2) gas is used as the purge gas. The purge gas storage unit 41C stores and supplies nitrogen gas mixed with hydrogen, i.e., gas mixed with hydrogen, as the purge gas.

[0041] Next, the purging method according to the first embodiment will be specifically described using the film forming apparatus 1. Fig. 2 is a flow diagram illustrating the purging method according to the first embodiment.

[0042] (Step S10) First, as a pre-processing step, the film forming apparatus 1 carries in a wafer W, which is an example of a processing substrate, and places it on the stage 11. Then, the film forming apparatus 1 reduces the pressure in the processing space SP to a vacuum atmosphere.

[0043] Furthermore, the film forming apparatus 1 adjusts the distance between the stage 11 and the shower head 22 to a predetermined distance. Specifically, the film forming apparatus 1 adjusts the distance H1 between the outer ring 12 and the outer edge portion 22P of the shower head 22 to 1 millimeter or less.

[0044] The distance H1 is preferably 1 mm or less, more preferably 0.5 mm or less, and even more preferably 0.25 mm or less. The distance H1 is desirably at least 0.1 mm or more in order to exhaust the gas in the processing space SP.

[0045] (Step S20) Next, the film forming apparatus 1 supplies a source gas into the processing space SP. The film forming apparatus 1 supplies, for example, titanium chloride (TiCl4) gas as the source gas into the processing space SP.

[0046] (Step S30) Next, the film forming apparatus 1 supplies a purge gas into the processing space SP in order to purge the source gas. The film forming apparatus 1 supplies, as the purge gas, for example, a gas mixed with hydrogen into the processing space SP.

[0047] (Step S40) Next, the film forming apparatus 1 supplies a reactive gas into the processing space SP. The film forming apparatus 1 supplies, for example, ammonia (NH3) gas as the reactive gas into the processing space SP.

[0048] (Step S50) Next, the film forming apparatus 1 supplies a purge gas into the processing space SP in order to purge the reactive gas. The film forming apparatus 1 supplies, as the purge gas, for example, a gas mixed with hydrogen into the processing space SP.

[0049] (Step S60) Next, the film forming apparatus 1 determines whether the process has been repeated a predetermined number of times. If the process has been repeated a predetermined number of times (YES in step S60), the film forming apparatus 1 proceeds to step S70. If the process has not been repeated a predetermined number of times (NO in step S60), the film forming apparatus 1 returns to step S20 and repeats the process.

[0050] (Step S70) Next, as a post-processing step, the film forming apparatus 1 returns the pressure in the processing space SP to atmospheric pressure, and then the film forming apparatus 1 unloads the processed wafer W placed on the stage 11.

[0051] Taking the case of forming a titanium nitride film layer as an example, the electrical resistivity when the purging method according to the first embodiment is used in the film forming apparatus 1 will be described. FIG. 3 is a diagram for explaining the relationship between the distance and the electrical resistivity in the purging method according to the first embodiment. The horizontal axis of FIG. 3 indicates the distance between the stage 11 and the shower head 22. Specifically, the horizontal axis of FIG. 3 indicates the distance H1 (unit: millimeters (mm)) between the outer ring 12 in the stage 11 and the outer edge portion 22P of the shower head 22. The vertical axis of FIG. 3 indicates the electrical resistivity (unit: microohm centimeters (μΩcm)) of the formed titanium nitride film. Line L11 indicates the result when a mixed gas of hydrogen gas and nitrogen gas is used as the purge gas, and line L12 indicates the result when nitrogen gas is used as the purge gas.

[0052] As shown in Fig. 3, in the purging method according to this embodiment, the electrical resistivity of the titanium nitride film formed can be reduced by using a gas mixed with hydrogen as the purge gas. Also, in the purging method according to this embodiment, the electrical resistivity of the titanium nitride film formed can be reduced by narrowing the gap H1. In particular, as shown in Fig. 3, in the purging method according to this embodiment, the gap H1 is preferably 1 mm or less, more preferably 0.5 mm or less, and even more preferably 0.25 mm or less.

[0053] The inventors found that when purging with hydrogen, simply increasing the amount of hydrogen only reduces the degree to which electrical resistivity can be reduced. FIG. 4 is a diagram for explaining the gas pressure when purging gas. FIG. 4 is a diagram showing the pressure of hydrogen gas and nitrogen gas when purging is repeated. The horizontal axis is time (unit: arbitrary unit), and the vertical axis is pressure (unit: arbitrary unit). Line L21 in FIG. 4 indicates the hydrogen gas pressure, and line L22 indicates the nitrogen gas pressure.

[0054] As shown in FIG. 4, the pressure fluctuation of hydrogen gas (line L21) is large relative to the pressure fluctuation of nitrogen gas (line L22). More specifically, the pressure of hydrogen gas decreases faster than that of nitrogen gas. In other words, hydrogen gas is exhausted quickly. Since hydrogen gas is exhausted quickly, it is considered that hydrogen remains on the processed substrate for a short period of time. Therefore, in order to reduce the electrical resistivity of the titanium nitride film formed by hydrogen gas, it is necessary to suppress the exhaust of hydrogen gas and increase the time that hydrogen remains on the processed substrate.

[0055] Therefore, the inventors discovered that when purging with a gas mixed with hydrogen, the electrical resistivity can be reduced by narrowing the distance between the stage 11 and the showerhead 22 to suppress the exhaust of hydrogen gas and allow hydrogen to remain in the vicinity of the processing substrate for a long period of time.

[0056] According to the purging method of the first embodiment, the electrical resistivity of the film formed can be reduced by narrowing the gap between the stage and the shower head.

[0057] Furthermore, according to the purging method of the first embodiment, the surface roughness of the film formed can be reduced by narrowing the gap between the stage and the shower head. Figure 5 is a diagram illustrating the relationship between the gap and the surface roughness in the purging method of the first embodiment.

[0058] In Fig. 5, the haze of a titanium nitride (TiN) film having a thickness of 10 nanometers is used as an index of surface roughness. The vertical axis of Fig. 5 indicates the haze (unit: ppm).

[0059] Ex1 on the horizontal axis of Fig. 5 shows the results when a mixed gas of hydrogen gas and nitrogen gas is used as the purge gas and the distance H1 between the outer ring 12 and the outer edge 22P of the showerhead 22 is set to 0.4 mm. Ex2 on the horizontal axis of Fig. 5 shows the results when a mixed gas of hydrogen gas and nitrogen gas is used as the purge gas and the distance H1 is set to 3 mm. Also, as a reference example, Ref1 on the horizontal axis of Fig. 5 shows the results when a mixed gas of nitrogen gas is used as the purge gas and the distance H1 is set to 0.4 mm, and Ref2 shows the results when the distance H1 is set to 3 mm.

[0060] 5, in the purging method according to the first embodiment, the surface roughness can be reduced by using a mixed gas of oxygen gas and nitrogen gas as the purge gas. Furthermore, in the purging method according to the first embodiment, the surface roughness can be further reduced by narrowing the gap between the stage and the shower head.

[0061] In the above example, the distance between the stage 11 and the shower head 22 is specified by the distance H1 between the outer ring 12 and the outer edge 22P, but the distance between the stage 11 and the central portion 22C of the shower head 22 may be adjusted to a predetermined distance. FIG. 6 is a diagram for explaining the distance in the purging method according to the first embodiment. In the table in FIG. 6, the first column shows the distance H1 between the outer ring 12 and the outer edge 22P. In the table in FIG. 6, the second column shows the distance H2 between the stage 11 and the central portion 22C of the shower head 22. In the table in FIG. 6, the third column shows the ratio of the volume of the processing space SP to the case where the distance H1 is 3 millimeters, which is set to 100%.

[0062] 6, the film forming apparatus 1 may be specified by the distance H2 between the stage 11 and the central portion 22C of the shower head 22, instead of the distance H1 between the outer ring 12 and the outer edge portion 22P. For example, the film forming apparatus 1 may be configured so that the distance H2 between the stage 11 and the central portion 22C of the shower head 22 is 8.6 mm or less. The distance H2 is preferably 8.6 mm or less, more preferably 8.1 mm or less, and even more preferably 7.85 mm or less. The distance H2 is preferably at least 0.1 mm or more in order to process the wafer W in the processing space SP.

[0063] Purging method according to the second embodiment A purging method according to the second embodiment will be described. In the purging method according to the second embodiment, the distance between the stage and the shower head is changed when purging is performed. The purging method according to the second embodiment is a purging method in a film forming apparatus including a substrate support unit including a stage for supporting a processing substrate and an outer ring provided around the stage, and a gas supply unit including a shower head provided opposite to the processing substrate and supplying a processing gas and a purge gas. In the purging method according to the second embodiment, a first distance between the outer ring and the outer edge of the shower head when purging is performed by supplying a gas mixed with hydrogen from the gas supply unit as a purge gas is narrower than a second distance between the outer ring and the outer edge of the shower head when film formation is performed by supplying a source gas from the gas supply unit.

[0064] The purging method according to the second embodiment will be described using the film forming apparatus 1. Fig. 7 is a flow diagram illustrating the purging method according to the second embodiment.

[0065] Note that for steps S20, S30, S40, S50, S60, and S70, the description of the purging method according to the first embodiment should be referred to, and detailed description thereof will be omitted here.

[0066] (Step S10) First, as a pre-processing step, the film forming apparatus 1 carries in a wafer W, which is an example of a processing substrate, and places it on the stage 11. Then, the film forming apparatus 1 reduces the pressure in the processing space SP to a vacuum atmosphere.

[0067] Furthermore, the film forming apparatus 1 adjusts the distance between the stage 11 and the shower head 22 to a predetermined distance. Specifically, the film forming apparatus 1 adjusts the distance H1 between the outer ring 12 and the outer edge portion 22P of the shower head 22 to 3 millimeters.

[0068] (Step S45) After step S40, the film forming apparatus 1 narrows the gap between the stage 11 and the shower head 22. That is, the gap (first gap) between the stage 11 and the shower head 22 when the purge gas is supplied is narrower than the gap (second gap) between the stage 11 and the shower head 22 when the source gas and the reactive gas are each supplied. Specifically, the film forming apparatus 1 sets the gap H1 between the outer ring 12 and the outer edge portion 22P of the shower head 22 to 1 mm or less. The gap when purging is performed is the same as that in the purging method according to the first embodiment.

[0069] (Step S55) After step S50, the film forming apparatus 1 widens the distance between the stage 11 and the shower head 22. The film forming apparatus 1 adjusts the distance between the stage 11 and the shower head 22 to a predetermined distance. Specifically, the film forming apparatus 1 adjusts the distance H1 between the outer ring 12 and the outer edge portion 22P of the shower head 22 to 3 millimeters.

[0070] According to the purging method of the second embodiment, the electrical resistivity of the film formed can be reduced by narrowing the gap between the stage and the shower head when purging. Also, according to the purging method of the second embodiment, the surface roughness of the film formed can be reduced by narrowing the gap between the stage and the shower head. Furthermore, according to the purging method of the second embodiment, the generation of the film can be promoted by widening the gap between the stage and the shower head when supplying the processing gas, and the variation in the film thickness can be reduced.

[0071] In the above example, the distance between the stage and the shower head is narrowed in the reaction gas purging process in step S50. However, the distance between the stage and the shower head may also be narrowed in the source gas purging process.

[0072] The purging method and the film forming apparatus according to the present embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The above-described embodiments can be modified and improved in various forms without departing from the scope and spirit of the appended claims. The matters described in the above-described embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent. [Explanation of symbols]

[0073] 1 Film deposition equipment 10 Substrate support 11 Stage 12 Outer Ring 20 Gas supply section 22. Shower Head 22C central part 22P Outer edge 40 Gas storage unit 41A Raw gas storage section 41B Reactant gas storage section 41C Purge gas storage unit H1, H2 interval SP Processing Space W wafer

Claims

1. a substrate support unit including a stage for supporting a substrate to be processed and an outer ring provided around the stage; a gas supply unit including a shower head disposed opposite to the processing substrate and supplying a processing gas and a purge gas; A purging method for a film forming apparatus comprising: When a gas mixed with hydrogen is supplied as the purge gas from the gas supply unit for purging, a distance between the outer ring and an outer edge of the shower head is 1 mm or less. Purging method.

2. The spacing is 0.5 millimeters or less. The method of claim 1 .

3. The spacing is 0.25 millimeters or less. The method of claim 2 .

4. a substrate support unit including a stage for supporting a substrate to be processed and an outer ring provided around the stage; a gas supply unit including a shower head disposed opposite to the processing substrate and supplying a processing gas and a purge gas; A purging method for a film forming apparatus comprising: When a gas mixed with hydrogen is supplied as the purge gas from the gas supply unit for purging, a distance between the stage and a center of the showerhead is 8.6 mm or less. Purging method.

5. The spacing is equal to or less than 8.1 millimeters. The method of claim 4.

6. The spacing is equal to or less than 7.85 millimeters. The method of claim 5.

7. The interval is an interval when purging is performed after supplying ammonia gas as the processing gas. The purging method according to any one of claims 1 to 6.

8. The processing gas includes a raw material gas containing titanium chloride gas and a reaction gas containing ammonia gas. The purging method according to any one of claims 1 to 6.

9. a substrate support unit including a stage for supporting a substrate to be processed and an outer ring provided around the stage; a gas supply unit including a shower head disposed opposite to the processing substrate and supplying a processing gas and a purge gas; A purging method for a film forming apparatus comprising: a first gap between the outer ring and an outer edge of the shower head when a gas mixed with hydrogen is supplied as the purge gas from the gas supply unit to perform purging, the first gap being narrower than a second gap between the outer ring and the outer edge of the shower head when a process gas is supplied from the gas supply unit; Purging method.

10. the first spacing being equal to or less than 1 millimeter; The method of claim 9.

11. the first spacing is less than or equal to 0.5 millimeters; The method of claim 10.

12. the first spacing is less than or equal to 0.25 millimeters; The method of claim 11.

13. The first interval is an interval when purging is performed after supplying ammonia gas as the processing gas. The purging method according to any one of claims 9 to 12.

14. The processing gas includes a raw material gas containing titanium chloride gas and a reaction gas containing ammonia gas. The purging method according to any one of claims 9 to 12.

15. a substrate support unit including a stage for supporting a substrate to be processed and an outer ring provided around the stage; a gas supply unit including a shower head disposed opposite to the processing substrate and supplying a processing gas and a purge gas; Equipped with When a gas mixed with hydrogen is supplied as the purge gas from the gas supply unit for purging, a distance between the outer ring and an outer edge of the shower head is 1 mm or less. Film deposition equipment.

16. a substrate support unit including a stage for supporting a substrate to be processed and an outer ring provided around the stage; a gas supply unit including a shower head disposed opposite to the processing substrate and supplying a processing gas and a purge gas; Equipped with When a gas mixed with hydrogen is supplied as the purge gas from the gas supply unit for purging, a distance between the stage and a center of the showerhead is 8.6 mm or less. Film deposition equipment.

17. a substrate support unit including a stage for supporting a substrate to be processed and an outer ring provided around the stage; a gas supply unit including a shower head disposed opposite to the processing substrate and supplying a processing gas and a purge gas; Equipped with a first gap between the outer ring and an outer periphery of the shower head when a gas mixed with hydrogen is supplied as the purge gas from the gas supply unit to purge the gas is narrower than a second gap between the outer ring and the outer periphery of the shower head when a source gas is supplied from the gas supply unit; Film deposition equipment.

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