Film forming method and film forming apparatus

Abstract

To provide a technique capable of controlling the in-plane distribution of film formation.SOLUTION: According to an aspect of the present disclosure, there is provided a film forming method including loading a plurality of substrates into a process container, heating an inside of the process container by a container heating unit provided around the process container, and heating a precursor gas in a first gas nozzle by a gas heating unit of the first gas nozzle and supplying the heated precursor gas from the first gas nozzle into the process container, wherein the supplying of the precursor gas includes changing a position where the precursor gas is activated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A technique is disclosed in which a seed layer is formed before forming a boron nitride film on a different substrate, and the incubation time is made uniform, thereby depositing a uniform boron nitride film on different substrates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-114918 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can control the in-plane distribution of film formation. [Means for solving the problem]

[0005] A film formation method according to one aspect of the present disclosure includes: loading a plurality of substrates into a processing vessel; heating the interior of the processing vessel using a vessel heating unit provided around the processing vessel; heating a source gas within a first gas nozzle using a gas heating unit included in the first gas nozzle; and supplying the heated source gas from the first gas nozzle into the processing vessel, wherein supplying the source gas includes changing a position at which the source gas is activated. [Effects of the Invention]

[0006] According to the present disclosure, the in-plane distribution of film formation can be controlled. [Brief explanation of the drawings]

[0007] [Figure 1]1 is a vertical cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 2] 1 is a horizontal cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 3] FIG. 2 is a cross-sectional view showing an example of a gas nozzle included in the film forming apparatus according to the embodiment. [Figure 4] 4 is a timing chart showing a film forming method according to a first example of the embodiment. [Figure 5] 6 is a timing chart showing a film forming method according to a second example of the embodiment. [Figure 6] FIG. 10 is a diagram showing the measurement results of the film formation rate of a boron film. [Figure 7] FIG. 10 is a diagram showing the measurement results of the in-plane distribution of the thickness of a boron film. 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 Figures 1 and 2. Figure 1 is a vertical cross-sectional view showing the film forming apparatus 1 according to an embodiment. Figure 2 is a horizontal cross-sectional view showing the film forming apparatus 1 according to an embodiment.

[0010] The film forming apparatus 1 is a batch type apparatus that processes a plurality of substrates W at once. The substrates W are, for example, semiconductor wafers. The film forming apparatus 1 includes a processing chamber 10, a gas supply unit 30, an exhaust unit 40, a chamber heating unit 50, and a control unit 90.

[0011] The processing vessel 10 can have its interior depressurized. The processing vessel 10 accommodates a substrate W. The processing vessel 10 has an inner tube 11 and an outer tube 12. The inner tube 11 has a cylindrical shape with a ceiling and an open lower end. The outer tube 12 has a cylindrical shape with a ceiling and an open lower end that covers the outside of the inner tube 11. The inner tube 11 and the outer tube 12 are made of a heat-resistant material such as quartz. The inner tube 11 and the outer tube 12 have a double-tube structure arranged coaxially.

[0012] A storage section 13 for storing a gas supply pipe is formed along the longitudinal direction (vertical direction) on the side wall of the inner pipe 11. For example, a part of the side wall of the inner pipe 11 is protruded outward to form a convex section 14, and the inside of the convex section 14 is formed as the storage section 13.

[0013] A rectangular opening 15 is formed along the longitudinal direction in the side wall of the inner tube 11. The opening 15 faces the storage portion 13.

[0014] The opening 15 is a gas exhaust port formed so as to be able to exhaust gas from the inner tube 11. The length of the opening 15 is the same as the length of the boat 16, or is formed so as to extend in the vertical direction and be longer than the length of the boat 16.

[0015] The lower end of the processing vessel 10 is supported by a cylindrical manifold 17. The manifold 17 is 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. This keeps the inside of the outer tube 12 airtight.

[0016] An annular support member 20 is provided on the inner wall of the upper portion of the manifold 17. The support member 20 supports the lower end of the inner tube 11. A lid member 21 is airtightly attached to the opening at the lower end of the manifold 17 via a sealing member 22 such as an O-ring. This airtightly closes the opening at the lower end of the processing vessel 10, i.e., the opening of the manifold 17. The lid member 21 is made of, for example, stainless steel.

[0017] A rotating shaft 24 is provided in the center of the lid 21, penetrating through the lid 21 via a magnetic fluid seal 23. The lower part of the rotating shaft 24 is rotatably supported by an arm 25A of an elevation mechanism 25 made up of a boat elevator.

[0018] A rotating plate 26 is provided at the upper end of the rotating shaft 24. A boat 16 holding substrates W is placed on the rotating plate 26 via a quartz heat retention stand 27. The boat 16 rotates by rotating the rotating shaft 24. The boat 16 moves up and down integrally with the lid 21 by raising and lowering the lifting mechanism 25. This allows the boat 16 to be inserted into and removed from the processing vessel 10. The boat 16 can be accommodated within the processing vessel 10. The boat 16 holds multiple (e.g., 50 to 150) substrates W in a shelf-like manner. The boat 16 holds the multiple substrates W approximately horizontally with spacing between them in the vertical direction.

[0019] The gas supply unit 30 supplies various gases into the inner tube 11. The gas supply unit 30 has a gas nozzle 31 and a gas nozzle 32. The gas nozzle 31 is an example of a first gas nozzle. The gas nozzle 32 is an example of a second gas nozzle. The gas nozzle 31 and the gas nozzle 32 are made of, for example, quartz. The gas supply unit 30 may further have another gas nozzle.

[0020] The gas nozzle 31 is fixed to the manifold 17. The gas nozzle 31 extends linearly in the vertical direction near the inner tube 11, and then bends in an L-shape within the manifold 17, extending horizontally and penetrating the manifold 17. A plurality of gas holes 31h are provided in a portion of the gas nozzle 31 located within the inner tube 11. The gas holes 31h are provided at predetermined intervals along the vertical direction. Each gas hole 31h ejects gas horizontally toward the substrate W from outside in the radial direction of the substrate W. Each gas hole 31h ejects gas parallel to the main surface of the substrate W.

[0021] A supply path L11 is connected to the gas nozzle 31. A source gas supply source G11, a mass flow controller F11, and a valve V11 are provided on the supply path L11, in this order from upstream to downstream in the gas flow direction. The source gas includes triethylborane (TEB). Triethylborane is an example of a source gas. The supply timing of the source gas from the supply source G11 is controlled by the valve V11, and the flow rate is adjusted to a predetermined value by the mass flow controller F11. The source gas flows from the supply path L11 into the gas nozzle 31 and is discharged into the inner tube 11 through a plurality of gas holes 31h.

[0022] A supply path L12 is connected to the supply path L11 downstream of the valve V11. A purge gas supply source G12, a mass flow controller F12, and a valve V12 are provided in this order from upstream to downstream in the gas flow direction. The purge gas contains nitrogen (N2). The supply timing of the purge gas from the supply source G12 is controlled by the valve V12, and the mass flow controller F12 adjusts the flow rate to a predetermined value. The purge gas flows from the supply path L12 into the gas nozzle 31 and is discharged into the inner pipe 11 through multiple gas holes 31h.

[0023] The gas nozzle 32 is fixed to the manifold 17. The gas nozzle 32 extends linearly in the vertical direction near the inner pipe 11, and then bends in an L-shape within the manifold 17, extending horizontally and penetrating the manifold 17. The gas nozzle 32 is provided alongside the gas nozzle 31 in the circumferential direction of the inner pipe 11. A plurality of gas holes 32h are provided in a portion of the gas nozzle 32 located within the inner pipe 11. The gas holes 32h are provided at predetermined intervals in the vertical direction. Each gas hole 32h ejects gas horizontally toward the substrate W from outside in the radial direction of the substrate W. Each gas hole 32h ejects gas parallel to the main surface of the substrate W.

[0024] A supply path L21 is connected to the gas nozzle 32. A reactive gas supply source G21, a mass flow controller F21, and a valve V21 are provided on the supply path L21, in this order from upstream to downstream in the gas flow direction. The reactive gas contains ammonia (NH3). Ammonia is an example of a reactive gas. The supply timing of the reactive gas from the supply source G21 is controlled by the valve V21, and the mass flow controller F21 adjusts the flow rate to a predetermined value. The reactive gas flows from the supply path L21 into the gas nozzle 32 and is discharged into the inner tube 11 through multiple gas holes 32h.

[0025] The exhaust unit 40 exhausts gas that is discharged from the inner tube 11 through the opening 15 and then discharged from a gas outlet 41 via a space P1 between the inner tube 11 and the outer tube 12. The gas outlet 41 is formed on the side wall of the upper part of the manifold 17, above the support unit 20. An exhaust flow path 42 is connected to the gas outlet 41. A pressure adjustment valve 43 and a vacuum pump 44 are sequentially disposed in the exhaust flow path 42, so that the inside of the processing chamber 10 can be exhausted.

[0026] The container heating part 50 is provided around the outer tube 12. The container heating part 50 is provided, for example, on the base plate 28. The container heating part 50 has a cylindrical shape so as to cover the outer tube 12. The container heating part 50 includes, for example, a heating element, and heats the inside of the processing container 10 and each substrate W in the processing container 10.

[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] [Gas nozzle] An example of the gas nozzle 31 included in the film formation apparatus 1 will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view showing an example of the gas nozzle 31 included in the film formation apparatus 1 according to the embodiment.

[0029] The gas nozzle 31 has an inner tube 210, an outer tube 220, and an adapter 230. The outer tube 220 and the adapter 230 are connected via a seal 235. The inner tube 210 is disposed inside the outer tube 220 and the adapter 230. An alumina core 201, a heating element 202, and a flexible cable 203 are provided inside the inner tube 210. The heating element 202 is wound around the alumina core 201. The flexible cable 203 connects the heating element 202 to a heater power supply (not shown). The heater power supply supplies power to the heating element 202 via the flexible cable 203. This causes the heating element 202 to generate heat, thereby heating the alumina core 201.

[0030] The source gas supplied from the supply port 231 of the adapter 230 passes through the space between the inner tube 210 and the adapter 230 and the space between the inner tube 210 and the outer tube 220, and is discharged from the gas hole 31h. Furthermore, when power is supplied from a heater power supply to the heating element 202, the source gas is heated, and the heated source gas is discharged from the gas hole 31h. Thus, the gas nozzle 31 includes the outer tube 220 through which the source gas flows, and a gas heating unit disposed within the outer tube 220 for heating the source gas flowing through the outer tube 220. The gas heating unit includes an alumina core 201 and a heating element 202. The gas heating unit is disposed within the outer tube 220, which is disposed within the inner tube 11.

[0031] [Film formation method] (Example 1) A film forming method according to a first example of an embodiment will be described with reference to Fig. 4. Fig. 4 is a timing chart showing the film forming method according to the first example of an embodiment. The film forming method according to the first example is a method of forming a boron film by chemical vapor deposition (CVD) using triethylborane. The film forming method according to the first example is performed under the control of a control unit 90.

[0032] First, the control unit 90 raises the arm 25A to load the boat 16 holding a plurality of substrates W into the processing vessel 10, and then airtightly closes the opening at the bottom of the processing vessel 10 with the lid 21. Next, the control unit 90 controls the exhaust unit 40 to set the pressure inside the processing vessel 10 to a set value, and controls the container heating unit 50 to set the temperature inside the processing vessel 10 to a predetermined value. The set temperature of the container heating unit 50 is, for example, a temperature higher than the thermal decomposition temperature of triethylborane.

[0033] Next, the control unit 90 executes a film formation process in the processing chamber 10 to form a boron film on the surface of each substrate W by chemical vapor deposition using triethylborane.

[0034] At time t11, the gas nozzle 31 starts supplying nitrogen into the inner tube 11. At time t11, the gas heater starts heating the gas nozzle 31. The supply of nitrogen from the gas nozzle 31 into the inner tube 11 continues until time t14. The heating of the gas nozzle 31 by the gas heater continues until time t13.

[0035] At time t12, the gas nozzle 31 begins supplying triethylborane into the inner tube 11. This results in the formation of a boron film on each substrate W. At this time, the gas nozzle 31 continues to be heated by the gas heater, so triethylborane is heated in the gas nozzle 31 and supplied into the inner tube 11. The triethylborane becomes more reactive when heated in the gas nozzle 31. This shifts the location where triethylborane is activated from within the inner tube 11 to within the inner tube 11 and the gas nozzle 31. This shifts the rate in the inner tube 11 from supply-limited to reaction-limited, increasing the amount of boron film formed at the center of each substrate W. As a result, a boron film with highly uniform thickness can be formed on each substrate W. In other words, the in-plane distribution of the film formation can be controlled. The set temperature of the gas heater is, for example, higher than the set temperature of the container heater 50. In this case, the reactivity of triethylborane tends to be high within the gas nozzle 31.

[0036] At time t13, the gas nozzle 31 stops supplying triethylborane into the inner tube 11. At time t13, the gas heater stops heating the gas nozzle 31. From time t13 to time t14, nitrogen continues to be supplied from the gas nozzle 31 into the inner tube 11. As a result, triethylborane remaining in the inner tube 11 is replaced with nitrogen. That is, the inside of the inner tube 11 is purged.

[0037] At time t14, the gas nozzle 31 stops supplying nitrogen into the inner tube 11.

[0038] 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 the unloading temperature, and then lowers the arm 25A to unload the boat 16 from the processing vessel 10. This completes the film formation process on the multiple substrates W.

[0039] According to the film formation method of the first example, while the inside of the inner tube 11 is heated by the vessel heating unit 50, triethylborane heated by the gas heating unit is supplied into the processing vessel 10 through the gas nozzle 31. The triethylborane becomes more reactive when heated in the gas nozzle 31. This shifts the location where triethylborane is activated from inside the inner tube 11 to inside the inner tube 11 and the gas nozzle 31. Therefore, inside the inner tube 11, the rate is changed from supply-limited to reaction-limited, and the amount of boron film formed at the center of each substrate W increases. As a result, a boron film with high in-plane thickness uniformity can be formed on each substrate W. In other words, the in-plane distribution of film formation can be controlled.

[0040] 4, the gas nozzle 31 is heated by the gas heater during the period from time t11 to time t13, but the timing at which the gas heater heats the gas nozzle 31 is not limited to this. For example, the gas heater may heat the gas nozzle 31 at the same timing as when the gas nozzle 31 supplies triethylborane into the inner tube 11. That is, the gas heater may heat the gas nozzle 31 during the period from time t12 to time t13.

[0041] (Example 2) A film formation method according to a second example of the embodiment will be described with reference to FIG. 5. FIG. 5 is a timing chart showing the film formation method according to the second example of the embodiment. The film formation method according to the second example differs from the film formation method according to the first example in that ammonia is supplied simultaneously with triethylborane. The other configurations of the film formation method according to the second example are the same as those of the film formation method according to the first example. That is, the film formation method according to the second example is a method of forming a boron nitride film by chemical vapor deposition in which triethylborane and ammonia are supplied simultaneously.

[0042] According to the film formation method of the second example, while the inside of the inner tube 11 is heated by the vessel heating unit 50, triethylborane heated by the gas heating unit is supplied into the processing vessel 10 through the gas nozzle 31. The triethylborane becomes more reactive when heated in the gas nozzle 31. This shifts the location where triethylborane is activated from inside the inner tube 11 to inside the inner tube 11 and the gas nozzle 31. Therefore, inside the inner tube 11, the rate is changed from supply-limited to reaction-limited, and the amount of boron nitride film formed at the center of each substrate W increases. As a result, a boron nitride film with high in-plane thickness uniformity can be formed on each substrate W. In other words, the in-plane distribution of the film formation can be controlled.

[0043] 5, the gas nozzle 31 is heated by the gas heater during the period from time t11 to time t13, but the timing at which the gas heater heats the gas nozzle 31 is not limited to this. For example, the gas heater may heat the gas nozzle 31 at the same timing as the gas nozzle 31 supplies triethylborane and ammonia into the inner tube 11. That is, the gas heater may heat the gas nozzle 31 during the period from time t12 to time t13.

[0044] [Experimental results] In the experiment, a boron film was formed by performing the film formation method shown in the timing chart of FIG. 4 under the following condition A in the film formation apparatus 1 according to the embodiment, and the film formation rate of the boron film and the in-plane distribution of the thickness of the boron film were measured.

[0045] <Condition A> Triethylborane supply time (time from time t12 to time t13): 60 seconds Pressure inside the processing vessel 10: 40 Pa (0.3 Torr) Container heating section 50 setting temperature: 300℃~450℃ Gas heating section temperature setting: 800℃

[0046] For comparison, a boron film was formed under condition X in which the gas nozzle 31 was not heated by the gas heater, in contrast to condition A, and the deposition rate of the boron film and the in-plane distribution of the thickness of the boron film were measured.

[0047] <Condition X> Triethylborane supply time: 60 seconds Pressure inside the processing vessel 10: 40 Pa (0.3 Torr) Container heating section 50 setting temperature: 300℃~450℃ Gas heating temperature setting: OFF

[0048] 6 is a diagram showing the measurement results of the deposition rate of the boron film, in which the horizontal axis represents the set temperature [°C] of the container heating unit 50 and the vertical axis represents the deposition rate [Å / min] of the boron film.

[0049] 6, when the set temperature of the container heating part 50 is 350°C or less, there is almost no difference in the deposition rate of the boron film between condition A and condition X. In contrast, when the set temperature of the container heating part 50 is 400°C or more, there is a difference in the deposition rate of the boron film between condition A and condition X.

[0050] Fig. 7 is a diagram showing the measurement results of the in-plane distribution of the thickness of the boron film. Fig. 7 shows the in-plane distribution of the thickness [Å] of the boron film when the set temperature of the container heating part 50 is 350°C, 400°C, and 450°C. In Fig. 7, circles indicate the in-plane distribution of the thickness of the boron film in the case of condition A, and triangles indicate the in-plane distribution of the thickness of the boron film in the case of condition X.

[0051] As shown in Figure 7, when the set temperature of the container heating part 50 is 350°C, there is almost no difference in the in-plane thickness distribution of the boron film between condition A and condition X. As shown in Figure 7, when the set temperature of the container heating part 50 is 400°C and 450°C, the in-plane thickness uniformity of the boron film is higher under condition A than under condition X. These results demonstrate that by using triethylborane heated in the gas nozzle 31 by the gas heating part, a boron film with high in-plane thickness uniformity can be formed regardless of the set temperature of the container heating part 50.

[0052] 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.

[0053] In the above embodiment, the source gas is triethylborane, but the present disclosure is not limited thereto. The source gas is, for example, a boron-containing gas. The boron-containing gas may be diborane (B2H6), trichlorosilane (BCl3), trimethylborane (TMB), triethylborane, dimethylaminoborane (DMAB), or a combination thereof. The source gas may be a silicon-containing gas. The silicon-containing gas may be, for example, an aminosilane, a silicon hydride, or a halogen-containing silicon. The aminosilane may be diisopropylaminosilane (DIPAS), trisdimethylaminosilane (3DMAS), bis(tert-butylaminosilane) (BTBAS), or a combination thereof. The silicon hydride may be monosilane (SiH4), disilane (Si2H6), trisilane (Si3H8), tetrasilane (Si4H 10The halogen-containing silicon may be a fluorine-containing silicon such as SiF, SiHF, SiH, F, or SiH, a chlorine-containing silicon such as SiCl, SiHCl, SiH, Cl, SiH, Cl, or SiCl, a bromine-containing silicon such as SiBr, SiHBr, SiH, Br, or SiHBr, or a combination thereof.

[0054] In the above embodiment, the reactive gas is ammonia, but the present disclosure is not limited thereto. The reactive gas is a gas that reacts with the source gas to produce a reaction product. The reactive gas is, for example, a nitriding gas. The nitriding gas may be ammonia, diazene (NH), hydrazine (NH), monomethylhydrazine (CH(NH)NH), or a combination thereof. The reactive gas may also be an oxidizing gas. The oxidizing gas may be ozone, oxygen (O), water vapor (H0), nitrogen dioxide (NO), or a combination thereof. [Explanation of symbols]

[0055] 1 Film deposition equipment 10 Processing container 31 Gas nozzle 50 Container heating section 201 Alumina Core 202 Heating element W substrate

Claims

1. Loading a plurality of substrates into a processing chamber; heating the inside of the processing vessel by a vessel heating unit provided around the processing vessel; heating a source gas in a first gas nozzle by a gas heating unit of the first gas nozzle, and supplying the heated source gas from the first gas nozzle into the processing vessel; and supplying the source gas includes changing a position where the source gas is activated; Film formation method.

2. supplying the source gas includes supplying the source gas parallel to main surfaces of the plurality of substrates; The film forming method according to claim 1 .

3. supplying the source gas includes activating at least a portion of the source gas in the first gas nozzle; The film forming method according to claim 1 .

4. The set temperature of the gas heating unit is higher than the set temperature of the container heating unit. The film forming method according to claim 1 .

5. the set temperature of the container heating unit is higher than the thermal decomposition temperature of the raw material gas; The film forming method according to claim 1 .

6. The source gas is a silicon-containing gas or a boron-containing gas. The film forming method according to claim 1 .

7. supplying a reaction gas that reacts with the source gas into the processing vessel from a second gas nozzle; supplying the source gas and the reaction gas simultaneously; The film forming method according to claim 1 , further comprising:

8. The reactive gas is an oxidizing gas or a nitriding gas. The film forming method according to claim 7 .

9. a processing vessel for accommodating a plurality of substrates; a container heating unit provided around the processing container and configured to heat the inside of the processing container; a first gas nozzle for supplying a source gas into the processing chamber; A control unit; Equipped with the first gas nozzle has a gas heating unit that heats the source gas inside the first gas nozzle, The control unit Loading a plurality of the substrates into the processing chamber; the container heating unit heats the inside of the processing container; the gas heating unit heats the source gas in the first gas nozzle, and the first gas nozzle supplies the heated source gas into the processing vessel; configured to run supplying the source gas includes changing a position where the source gas is activated; Film deposition equipment.

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