Method for modifying silicon oxide film and substrate processing apparatus

Abstract

A method for modifying a silicon oxide film according to one aspect of the present disclosure comprises a step of preparing a substrate on which a silicon oxide film is formed and a step of modifying the silicon oxide film, wherein the step of modifying the silicon oxide film comprises: (a) a step of exposing the surface of the silicon oxide film to a plasma generated from a first gas containing a hydrogen-containing gas; (b) a step of exposing the surface of the silicon oxide film to a plasma generated from a second gas containing an inert gas and not containing a hydrogen-containing gas; and (c) a step of exposing the surface of the silicon oxide film to a plasma generated from a third gas containing a nitrogen-containing gas.

Description

Technology Field

[0001] The present disclosure relates to a method for modifying a silicon oxide film and a substrate processing apparatus. Background Technology

[0002] A technique for modifying a silicon oxide film is known by exposing a substrate having a silicon oxide film formed thereon to a plasma generated from a mixed gas of hydrogen and argon gases and a plasma generated from argon gas. (See, for example, Patent Document 1) Prior art literature

[0003] Japanese Patent Publication No. JP 2023-182324 The problem to be solved

[0004] The present disclosure provides a technology capable of improving the electrical properties of a silicon oxide film. means of solving the problem

[0005] A method for modifying a silicon oxide film according to one aspect of the present disclosure comprises a step of preparing a substrate on which a silicon oxide film is formed and a step of modifying the silicon oxide film, wherein the step of modifying the silicon oxide film comprises: (a) a step of exposing the surface of the silicon oxide film to a plasma generated from a first gas containing a hydrogen-containing gas; (b) a step of exposing the surface of the silicon oxide film to a plasma generated from a second gas containing an inert gas and not containing a hydrogen-containing gas; and (c) a step of exposing the surface of the silicon oxide film to a plasma generated from a third gas containing a nitrogen-containing gas. Effects of the invention

[0006] According to the present disclosure, the electrical properties of a silicon oxide film can be improved. Brief explanation of the drawing

[0007] FIG. 1 is a flowchart illustrating a method for modifying a silicon oxide film according to a first embodiment. FIG. 2a is a cross-sectional view showing a method for modifying a silicon oxide film according to a first embodiment. FIG. 2b is a cross-sectional view illustrating a method for modifying a silicon oxide film according to a first embodiment. FIG. 2c is a cross-sectional view showing a method for modifying a silicon oxide film according to a first embodiment. FIG. 2d is a cross-sectional view illustrating a method for modifying a silicon oxide film according to a first embodiment. Figure 3 is a flowchart showing an example of a step for forming a silicon oxide film. FIG. 4 is a drawing showing an example of a processing system according to an embodiment. FIG. 5 is a drawing showing an example of a substrate processing device according to an embodiment. FIG. 6 is a flowchart illustrating a method for modifying a silicon oxide film according to a second embodiment. FIG. 7 is a flowchart illustrating a method for modifying a silicon oxide film according to a third embodiment. FIG. 8 is a flowchart illustrating a method for modifying a silicon oxide film according to a fourth embodiment. FIG. 9 is a flowchart illustrating a method for modifying a silicon oxide film according to a fifth embodiment. FIG. 10 is a flowchart illustrating a method for modifying a silicon oxide film according to a sixth embodiment. Figure 11 is a diagram (1) showing the leakage current density of a silicon oxide film. Figure 12 is a diagram (2) showing the leakage current density of a silicon oxide film. Figure 13 is a diagram (3) showing the leakage current density of a silicon oxide film. Specific details for implementing the invention

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the attached drawings. In all attached drawings, identical or corresponding reference numerals are assigned to identical or corresponding members or parts, and redundant descriptions are omitted.

[0009] [First Embodiment]

[0010] (Method for modifying silicon oxide film)

[0011] Referring to FIGS. 1 to 3, a method for modifying a silicon oxide film according to a first embodiment is described. The method for modifying a silicon oxide film according to the first embodiment has steps S11 to S15 shown in FIG. 1.

[0012] In step S11, a silicon oxide film (102) is formed on an insulating film (101) formed on a substrate (100) as shown in FIG. 2a. The insulating film (101) is, for example, a low-dielectric constant (Low-k) film. The type of insulating film (101) is not particularly limited, but is, for example, a SiO film, a SiN film, a SiOC film, a SiON film, or a SiOCN film. A SiO film refers to a film containing silicon (Si) and oxygen (O). The atomic ratio of Si to O in a SiO film is not limited to 1:1. It is the same for SiN films, SiOC films, SiON films, and SiOCN films. Step S11 includes, for example, steps S111 to S113 shown in FIG. 3.

[0013] In step S111, a metal catalyst gas is supplied to the substrate (100) to adsorb the metal catalyst gas onto the insulating film (101). The metal catalyst gas is, for example, trimethylaluminum (TMA) gas. In step S111, the substrate (100) is heated to a low temperature, for example, between 120°C and 300°C.

[0014] Step S112 is performed after Step S111. In Step S112, a silanol-containing gas is supplied to the substrate (100) and reacted with a metal catalyst gas adsorbed on the insulating film (101) to form a silicon oxide film (102). The silanol-containing gas is, for example, TPSOL (Tris(tert-pentoxy)silanol) or TBSOL (Tris(tert-butoxy)silanol). In Step S112, the substrate (100) is heated to a low temperature, for example, between 120°C and 300°C.

[0015] Step S113 is performed after Step S112. In Step S113, it is determined whether Steps S111 to S112 have been performed a set number of times. If the number of times has not reached the set number (NO in Step S113), Steps S111 to S112 are performed again. If the number of times has reached the set number (YES in Step S113), the process is terminated because the film thickness of the silicon oxide film (102) has reached a predetermined film thickness with respect to the plasma treatment. The set number of times in Step S113 is set according to the film deposition amount so that the silicon oxide film (102) formed in Step S11 can reach a predetermined film thickness. The film deposition amount can be adjusted according to the supply amount of silanol-containing gas, etc. The predetermined film thickness is, for example, 2 nm or more and 5 nm or less. In this case, in Steps S12 to S15, plasma is likely to act on the entire film thickness direction of the silicon oxide film (102) formed in the preceding Step S11. Accordingly, the silicon oxide film (102) is modified throughout the entire thickness direction. Meanwhile, if the thickness of the silicon oxide film (102) formed in step S11 is greater than a predetermined film thickness, it is difficult for the modification by plasma to act at a deep position from the surface of the silicon oxide film (102) in steps S12 to S15. The number of steps S113 may be one or two or more.

[0016] Step S12 is performed after Step S11. In Step S12, the surface of the silicon oxide film (102) is exposed to a plasma (P1) generated from a first gas containing hydrogen gas, as illustrated in FIG. 2b. This removes impurities in the film, including Si-OH bonds. In Step S12, when the silicon oxide film (102) is exposed to the plasma (P1), hydrogen defects may be generated in the silicon oxide film (102) through the reaction between the active species contained in the plasma (P1) and the silicon oxide film (102). The first gas may be used mixed with argon gas. In Step S12, the substrate (100) may be heated to a higher temperature than in Step S11. In this case, impurities in the film, including Si-OH bonds, are easily removed.

[0017] An example of the processing conditions for step S12 is as follows.

[0018] * Hydrogen gas flow rate: 200 sccm~3000 sccm

[0019] * Argon gas flow rate: 600 sccm~6000 sccm

[0020] * Substrate temperature: 120℃~350℃

[0021] * Processing pressure: 1 Torr~5 Torr (133 Pa~667 Pa)

[0022] * Processing time: 10–60 seconds

[0023] Step S13 is performed after Step S12. In Step S13, as illustrated in FIG. 2c, the surface of the silicon oxide film (102) is exposed to a plasma (P2) generated from a second gas containing argon gas but not hydrogen gas. Through this, hydrogen defects generated in the silicon oxide film (102) in Step S12 are removed. Consequently, both impurities in the film, including Si-OH bonds, and hydrogen defects can be reduced. Therefore, it is easier to reduce the leakage current of the silicon oxide film (102) compared to modification using only plasma (P1) or modification using only plasma (P2). In Step S13, the substrate (100) can be heated to a higher temperature than in Step S11. In this case, hydrogen defects are easily removed. When transitioning from Step S12 to Step S13, the plasma (P1) may be maintained and then switched to plasma (P2), or the plasma (P1) may be stopped and then plasma (P2) generated.

[0024] An example of the processing conditions for step S13 is as follows.

[0025] * Argon gas flow rate: 600 sccm~6000 sccm

[0026] * Substrate temperature: 120℃~350℃

[0027] * Processing pressure: 1 Torr~5 Torr (133 Pa~667 Pa)

[0028] * Processing time: 10–60 seconds

[0029] Step S14 is performed after Step S13. In Step S14, it is determined whether Steps S12 to S13 have been performed a first time. If the number of times the steps have been performed has not reached the first time (NO in Step S14), Steps S12 to S13 are performed again. On the other hand, if the number of times the steps have reached the first time (YES in Step S14), the process is carried out to Step S15. The first time is set, for example, according to the film thickness of the silicon oxide film (102) formed in Step S11. The first time may be one time or two or more times. The first time is preferably 2 to 6 times. When transitioning from Step S13 to Step S12, the plasma (P2) may be maintained and then switched to plasma (P1), or the plasma (P1) may be generated after stopping the plasma (P2).

[0030] In step S15, the surface of the silicon oxide film (102) is exposed to a plasma (P3) generated from a third gas containing nitrogen gas, as illustrated in FIG. 2d. This allows for further reduction of the leakage current of the silicon oxide film (102). It is believed that this is because electrically active defects present on the surface and inside the silicon oxide film (102) are deactivated as the silicon oxide film (102) is exposed to the plasma (P3). The third gas may include argon gas. The third gas may include hydrogen gas. The flow rate of nitrogen gas included in the third gas may be between 5% and 40%. In step S15, the substrate (100) may be heated to a higher temperature than in step S11. In this case, the leakage current is easily reduced. When transitioning from step S13 to step S15, the plasma (P2) may be maintained and then switched to plasma (P3), or the plasma (P3) may be generated after stopping the plasma (P2).

[0031] An example of the processing conditions for step S15 is as follows.

[0032] * Nitrogen gas flow rate: 200 sccm~2000 sccm

[0033] * Argon gas flow rate: 600 sccm~6000 sccm

[0034] * Hydrogen gas flow rate: 200 sccm~2000 sccm

[0035] * Substrate temperature: 120℃~350℃

[0036] * Processing pressure: 1 Torr~5 Torr (133 Pa~667 Pa)

[0037] * Processing time: 10–60 seconds

[0038] As described above, according to the first embodiment, the method for modifying a silicon oxide film comprises a process of preparing a substrate (100) on which a silicon oxide film (102) is formed and a process of modifying the silicon oxide film (102). The process of modifying the silicon oxide film (102) includes steps S12, S13, and S15. In step S12, the surface of the silicon oxide film (102) is exposed to a plasma (P1) generated from a first gas containing hydrogen gas. In step S13, the surface of the silicon oxide film (102) is exposed to a plasma (P2) generated from a second gas containing argon gas but not hydrogen gas. In step S15, the surface of the silicon oxide film (102) is exposed to a plasma (P3) generated from a third gas containing nitrogen gas. In this case, the leakage current of the silicon oxide film (102) can be reduced. That is, the electrical characteristics of the silicon oxide film (102) can be improved.

[0039] (Processing system)

[0040] Referring to FIG. 4, an example of a processing system (PS) for carrying out a method for modifying a silicon oxide film according to a first embodiment will be described.

[0041] The processing system (PS) is equipped with processing devices (PM1~PM4), a vacuum transfer room (VTM), load lock rooms (LL1~LL3), an atmospheric transfer room (LM), load ports (LP1~LP3), and an overall control unit (CU).

[0042] Processing devices (PM1 to PM4) are each connected to a vacuum transport chamber (VTM) through gate valves (G11 to G14). The processing devices (PM1 to PM4) are configured to allow the interior to be depressurized to a predetermined vacuum atmosphere. The processing devices (PM1 to PM4) accommodate a substrate (W) inside and perform a desired processing.

[0043] The vacuum transport chamber (VTM) is configured to allow the interior to be depressurized to a predetermined vacuum atmosphere. The vacuum transport chamber (VTM) is equipped with a first transport device (TR1) capable of transporting a substrate (W) in a depressurized state. The first transport device (TR1) transports the substrate (W) to processing devices (PM1~PM4) and load lock chambers (LL1~LL3). The first transport device (TR1) has, for example, two transport arms (FK11, FK12) that can move independently.

[0044] The load lock chambers (LL1–LL3) are each connected to the vacuum return chamber (VTM) through gate valves (G21–G23). The load lock chambers (LL1–LL3) are each connected to the atmospheric return chamber (LM) through gate valves (G31–G33). The load lock chambers (LL1–LL3) are configured to switch their interiors between an atmospheric atmosphere and a vacuum atmosphere.

[0045] The interior of the atmospheric transport chamber (LM) is an atmospheric environment. Inside the atmospheric transport chamber (LM), for example, a downflow of clean air is formed. Inside the atmospheric transport chamber (LM), an aligner (AN) for aligning the substrate (W) is provided. The aligner (AN) may be provided outside the atmospheric transport chamber (LM). A second transport device (TR2) is provided in the atmospheric transport chamber (LM). The second transport device (TR2) transports the substrate (W) to the load lock chambers (LL1~LL3), load ports (LP1~LP3), and the aligner (AN).

[0046] Load ports (LP1 to LP3) are provided on the long side wall of the waiting transport room (LM). A carrier (C) is installed in the load ports (LP1 to LP3). The carrier (C) includes a carrier (C) containing a substrate (W) and an empty carrier (C). The carrier (C) may be, for example, a FOUP (Front Opening Unified Pod).

[0047] The overall control unit (CU) may be, for example, a computer. The overall control unit (CU) is equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and an auxiliary storage device. The CPU operates based on a program stored in the ROM or the auxiliary storage device and controls each part of the processing system (PS). For example, the overall control unit (CU) controls the operation of the processing unit (PM1~PM4), the first transfer unit (TR1), the second transfer unit (TR2), and the gate valves (G11~G14, G21~G23, G31~G33). For example, the overall control unit (CU) controls the operation of switching the interior of the load lock chambers (LL1~LL3) between an atmospheric atmosphere and a vacuum atmosphere.

[0048] Next, the operation of the processing system (PS) is described. First, the second conveying device (TR2) removes the substrate (W) from the carrier (C), conveys the removed substrate (W) to the aligner (AN), and exits from the aligner (AN). Next, the aligner (AN) performs alignment of the substrate (W). Next, the second conveying device (TR2) removes the substrate (W) from the aligner (AN), conveys the removed substrate (W) to the load lock chamber (LL1), and exits from the load lock chamber (LL1). Next, the interior of the load lock chamber (LL1) is switched from an atmospheric atmosphere to a vacuum atmosphere. After that, the first conveying device (TR1) removes the substrate (W) from the load lock chamber (LL1) and conveys the removed substrate (W) to the processing device (PM1).

[0049] Next, the processing device (PM1) performs steps S11 to S15 in the method for modifying a silicon oxide film according to the first embodiment.

[0050] Next, the first conveying device (TR1) removes the substrate (W) from the processing device (PM1), conveys the removed substrate (W) to the load lock chamber (LL3), and removes it from the load lock chamber (LL3). Subsequently, the interior of the load lock chamber (LL3) is switched from a vacuum atmosphere to an atmospheric atmosphere. After that, the second conveying device (TR2) removes the substrate (W) from the load lock chamber (LL3) and receives the removed substrate (W) into a carrier (C). Then, the processing of the substrate (W) is completed.

[0051] In the operation of the above processing system (PS), the case in which steps S11 to S15 are performed using one processing device (PM1) has been described, but it is not limited thereto. For example, steps S11 to S15 may be performed using at least one of the other processing devices (PM2 to PM4). For example, steps S11 to S15 may be performed using two or more of the four processing devices (PM1 to PM4). For example, step S11 may be performed using processing device (PM1), and steps S12 to S15 may be performed using processing device (PM2). In this case, the time required for temperature change when performing steps S11 and steps S12 to S15 at different temperatures can be reduced. Thus, productivity is improved.

[0052] (Substrate processing device)

[0053] Referring to FIG. 5, an example of a substrate processing device used as a processing device (PM1 to PM4) equipped in the processing system (PS) of FIG. 4 will be described.

[0054] The substrate processing device has a processing container (1), a mounting base (2), a shower head (3), an exhaust unit (4), a gas supply unit (5), an RF power supply unit (8), and a control unit (9).

[0055] The processing vessel (1) is constructed of a metal such as aluminum and has a roughly cylindrical shape. The processing vessel (1) accommodates a substrate (W). The substrate (W) may be, for example, a semiconductor wafer. An inlet / outlet (11) for bringing in or taking out the substrate (W) is formed on the side wall of the processing vessel (1). The inlet / outlet (11) is opened and closed by a gate valve (12). An annular exhaust duct (13) with a rectangular cross-section is provided on the main body of the processing vessel (1). A slit (13a) is formed along the inner surface of the exhaust duct (13). An exhaust port (13b) is formed on the outer wall of the exhaust duct (13). A ceiling wall (14) is provided on the upper surface of the exhaust duct (13) to block the upper opening of the processing vessel (1) through an insulating member (16). The space between the exhaust duct (13) and the insulating member (16) is hermetically sealed by a sealing member (15). The sealing member (15) may be, for example, an O-ring. The partition member (17) divides the interior of the processing container (1) vertically when the mounting base (2) (and cover member (22)) rises to the processing position described later.

[0056] The support plate (2) supports the substrate (W) horizontally within the processing vessel (1). The support plate (2) has a disc shape. The outer diameter of the support plate (2) is, for example, larger than the outer diameter of the substrate (W). The support plate (2) is formed from a ceramic material such as AlN or a metal material such as aluminum or nickel alloy. A heater (21) for heating the substrate (W) is embedded inside the support plate (2). The heater (21) is powered by a heater power source (not shown) and generates heat. A thermocouple (not shown) is provided near the upper surface of the support plate (2). By controlling the output of the heater (21) according to the temperature signal of the thermocouple, the substrate (W) is controlled to a predetermined temperature. The support plate (2) is provided with a cover member (22) formed of a ceramic such as alumina to cover the outer periphery area of ​​the upper surface and the side.

[0057] A support member (23) is provided on the bottom surface of the mounting stand (2). The support member (23) supports the mounting stand (2). The support member (23) extends downward from the center of the bottom surface of the mounting stand (2) through a hole formed in the bottom wall of the processing container (1) to the bottom of the processing container (1). The bottom end of the support member (23) is connected to a lifting mechanism (24). The lifting mechanism (24) raises the mounting stand (2) through the support member (23) between the processing position shown in FIG. 5 and the conveying position below it, indicated by the dashed line, where the substrate (W) can be conveyed. A flange portion (25) is installed on the bottom of the support member (23) of the processing container (1). A bellows (26) is provided between the bottom surface of the processing container (1) and the flange portion (25). The bellows (26) separates the atmosphere inside the processing container (1) from the outside air and extends and retracts according to the lifting and lowering movement of the mounting stand (2).

[0058] Near the bottom surface of the processing container (1), three support pins (27) (only two are shown) are provided to protrude upward from the lifting plate (27a). The support pins (27) are raised and lowered through the lifting plate (27a) by a lifting mechanism (28) provided at the bottom of the processing container (1). The support pins (27) are inserted and passed through a through hole (2a) provided in the loading platform (2) at the transfer position, so that they can protrude and be retracted relative to the upper surface of the loading platform (2). By raising and lowering the support pins (27), the substrate (W) is transferred between the first transfer device (TR1) (Fig. 4) and the loading platform (2).

[0059] The shower head (3) supplies processing gas into the processing vessel (1) in the form of a shower. The shower head (3) is made of metal and is provided to face the mounting base (2). The shower head (3) has a diameter almost identical to that of the mounting base (2). The shower head (3) has a main body (31) and a shower plate (32). The main body (31) is fixed to the ceiling wall (14) of the processing vessel (1). The shower plate (32) is connected below the main body (31). A gas diffusion space (33) is formed between the main body (31) and the shower plate (32). In the gas diffusion space (33), a gas introduction hole (36) is provided to penetrate the center of the ceiling wall (14) and the main body (31). An annular projection (34) protruding downward is formed on the periphery of the shower plate (32). A gas discharge hole (35) is formed on the flat portion inside the annular projection (34). When the mounting base (2) is in the processing position, a processing space (38) is formed between the mounting base (2) and the shower plate (32), and an annular gap (39) is formed so that the upper surface of the cover member (22) and the annular projection (34) are close together.

[0060] The exhaust section (4) exhausts the interior of the processing vessel (1). The exhaust section (4) has an exhaust pipe (41) and an exhaust mechanism (42). The exhaust pipe (41) is connected to the exhaust port (13b). The exhaust mechanism (42) has a vacuum pump connected to the exhaust pipe (41) and a pressure control valve. During processing, the gas inside the processing vessel (1) reaches the exhaust duct (13) through the slit (13a) and is exhausted from the exhaust duct (13) through the exhaust pipe (41) by the exhaust mechanism (42).

[0061] The gas supply unit (5) supplies various processing gases to the shower head (3). The gas supply unit (5) has a gas source (51) and a gas line (52). The gas source (51) includes a supply source for various processing gases, a mass flow controller, and a valve. The various processing gases include gases used in the method for modifying a silicon oxide film according to at least the first embodiment. The various gases are introduced from the gas source (51) into the gas diffusion space (33) through the gas line (52) and the gas introduction hole (36).

[0062] The substrate processing device is a capacitively coupled plasma device, wherein the mounting base (2) functions as a lower electrode and the shower head (3) functions as an upper electrode. The mounting base (2) is grounded. The shower head (3) is connected to an RF power supply unit (8).

[0063] The RF power supply unit (8) supplies high-frequency power (hereinafter also referred to as 'RF power') to the shower head (3). The RF power supply unit (8) has an RF power source (81), a matching unit (82), and a power supply line (83). The RF power source (81) is a power source that generates RF power. The RF power has a frequency suitable for generating plasma. The frequency of the RF power is, for example, a frequency within the range of 450 kHz, which is a low frequency band, to 2.45 GHz, which is a microwave band. The RF power source (81) is connected to the main body (31) through the matching unit (82) and the power supply line (83). The matching unit (82) has a circuit for matching the load impedance to the internal impedance of the RF power source (81). The RF power supply unit (8) may be configured to supply RF power to the mounting base (2).

[0064] The control unit (9) is, for example, a computer. The control unit (9) is equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), auxiliary storage device, etc. The CPU operates based on a program stored in the ROM or auxiliary storage device and controls the operation of the substrate processing device. The control unit (9) may be provided inside the substrate processing device or outside of it. When the control unit (9) is provided outside of the substrate processing device, the control unit (9) can control the substrate processing device by means of communication such as wired or wireless communication.

[0065] [Second Embodiment]

[0066] Referring to FIG. 6, a method for modifying a silicon oxide film according to a second embodiment is described. The method for modifying a silicon oxide film according to the second embodiment has steps S21 to S26 as illustrated in FIG. 6. Steps S21 to S24 are identical to steps S11 to S14. Step S26 is identical to step S15.

[0067] Step S25 is performed when the number of times steps S22 to S23 are performed in step S24 reaches the first number (YES in step S24). In step S25, it is determined whether steps S21 to S24 have been performed a second time. If the number of times has not reached the second number (NO in step S25), steps S21 to S24 are performed again. On the other hand, if the number of times has reached the second number (YES in step S25), the process proceeds to step S26. The second number is set, for example, according to the target film thickness of the silicon oxide film (102). The second number may be one time or two or more times.

[0068] As described above, according to the second embodiment, the method for modifying a silicon oxide film comprises a process of preparing a substrate (100) on which a silicon oxide film (102) is formed and a process of modifying the silicon oxide film (102). The process of modifying the silicon oxide film (102) includes steps S22, S23, and S26. In step S22, the surface of the silicon oxide film (102) is exposed to a plasma (P1) generated from a first gas containing hydrogen gas. In step S23, the surface of the silicon oxide film (102) is exposed to a plasma (P2) generated from a second gas containing argon gas but not hydrogen gas. In step S26, the surface of the silicon oxide film (102) is exposed to a plasma (P3) generated from a third gas containing nitrogen gas. In this case, the leakage current of the silicon oxide film (102) can be reduced, similar to the method for modifying a silicon oxide film according to the first embodiment. That is, the electrical properties of the silicon oxide film (102) can be improved.

[0069] The method for modifying a silicon oxide film according to the second embodiment can be carried out using a processing system (PS) according to the first embodiment, just like the method for modifying a silicon oxide film according to the first embodiment.

[0070] [Third Embodiment]

[0071] Referring to FIG. 7, a method for modifying a silicon oxide film according to a third embodiment is described. The method for modifying a silicon oxide film according to the third embodiment has steps S31 to S37 as illustrated in FIG. 7. Steps S31 to S34 are identical to steps S11 to S14. Step S35 is identical to step S25. Step S36 is identical to step S15.

[0072] Step S37 is performed after Step S36. In Step S37, it is determined whether Steps S31 through S36 have been performed a third time. If the number of times the steps have been performed has not reached a third time (NO in Step S37), Steps S31 through S36 are performed again. On the other hand, if the number of times the steps have reached a third time (YES in Step S37), the processing is terminated. The third time is set, for example, according to the target film thickness of the silicon oxide film (102). The third time may be one time or two or more times.

[0073] As described above, according to the third embodiment, the method for modifying a silicon oxide film comprises a process of preparing a substrate (100) on which a silicon oxide film (102) is formed and a process of modifying the silicon oxide film (102). The process of modifying the silicon oxide film (102) includes steps S32, S33, and S36. In step S32, the surface of the silicon oxide film (102) is exposed to a plasma (P1) generated from a first gas containing hydrogen gas. In step S33, the surface of the silicon oxide film (102) is exposed to a plasma (P2) generated from a second gas containing argon gas but not hydrogen gas. In step S36, the surface of the silicon oxide film (102) is exposed to a plasma (P3) generated from a third gas containing nitrogen gas. In this case, the leakage current of the silicon oxide film (102) can be reduced, similar to the method for modifying a silicon oxide film according to the first embodiment. That is, the electrical properties of the silicon oxide film (102) can be improved.

[0074] The method for modifying a silicon oxide film according to the third embodiment can be carried out using a processing system (PS) according to the first embodiment, just like the method for modifying a silicon oxide film according to the first embodiment.

[0075] [Fourth Embodiment]

[0076] Referring to FIG. 8, a method for modifying a silicon oxide film according to a fourth embodiment is described. The method for modifying a silicon oxide film according to the fourth embodiment has steps S41 to S45 as illustrated in FIG. 8. The method for modifying a silicon oxide film according to the fourth embodiment differs from the method for modifying a silicon oxide film according to the first embodiment in that it is configured to expose the surface of the silicon oxide film (102) in the order of plasma (P3), plasma (P1), and plasma (P2).

[0077] Step S41 is identical to Step S11. Step S42 is identical to Step S15. Steps S43–S45 are identical to Steps S12–S14.

[0078] As described above, according to the method for modifying a silicon oxide film according to the fourth embodiment, the method comprises a process of preparing a substrate (100) on which a silicon oxide film (102) is formed and a process of modifying the silicon oxide film (102). The process of modifying the silicon oxide film (102) includes steps S43, S44, and S42. In step S43, the surface of the silicon oxide film (102) is exposed to a plasma (P1) generated from a first gas containing hydrogen gas. In step S44, the surface of the silicon oxide film (102) is exposed to a plasma (P2) generated from a second gas containing argon gas but not hydrogen gas. In step S42, the surface of the silicon oxide film (102) is exposed to a plasma (P3) generated from a third gas containing nitrogen gas. In this case, the leakage current of the silicon oxide film (102) can be reduced, similar to the method for modifying a silicon oxide film according to the first embodiment. That is, the electrical properties of the silicon oxide film (102) can be improved.

[0079] The method for modifying a silicon oxide film according to the fourth embodiment can be carried out using a processing system (PS) according to the first embodiment, just like the method for modifying a silicon oxide film according to the first embodiment.

[0080] [Fifth Embodiment]

[0081] Referring to FIG. 9, a method for modifying a silicon oxide film according to a fifth embodiment is described. The method for modifying a silicon oxide film according to a fifth embodiment has steps S51 to S56 as illustrated in FIG. 9. Steps S51 to S55 are identical to steps S41 to S45.

[0082] Step S56 is performed when the number of times steps S53 to S54 are performed in step S55 reaches the first number (YES in step S55). In step S56, it is determined whether steps S52 to S55 have been performed a second time. If the number of times has not reached the second number (NO in step S56), steps S52 to S55 are performed again. Meanwhile, if the number of times has reached the second number (YES in step S56), the processing is terminated. The second number is set, for example, according to the film thickness of the silicon oxide film (102) formed in step S51. The second number may be one time or two or more times.

[0083] As described above, according to the method for modifying a silicon oxide film according to the fifth embodiment, the method comprises a process of preparing a substrate (100) on which a silicon oxide film (102) is formed and a process of modifying the silicon oxide film (102). The process of modifying the silicon oxide film (102) includes steps S53, S54, and S52. In step S53, the surface of the silicon oxide film (102) is exposed to a plasma (P1) generated from a first gas containing hydrogen gas. In step S54, the surface of the silicon oxide film (102) is exposed to a plasma (P2) generated from a second gas containing argon gas but not hydrogen gas. In step S52, the surface of the silicon oxide film (102) is exposed to a plasma (P3) generated from a third gas containing nitrogen gas. In this case, the leakage current of the silicon oxide film (102) can be reduced, similar to the method for modifying a silicon oxide film according to the first embodiment. That is, the electrical properties of the silicon oxide film (102) can be improved.

[0084] The method for modifying a silicon oxide film according to the fifth embodiment can be carried out using a processing system (PS) according to the first embodiment, just like the method for modifying a silicon oxide film according to the first embodiment.

[0085] [Sixth Embodiment]

[0086] Referring to FIG. 10, a method for modifying a silicon oxide film according to a sixth embodiment is described. The method for modifying a silicon oxide film according to a sixth embodiment has steps S61 to S67 as illustrated in FIG. 10. Steps S61 to S66 are identical to steps S51 to S56.

[0087] Step S67 is performed when the number of times steps S62 to S65 are performed in step S66 reaches the second time (YES in step S66). In step S67, it is determined whether steps S61 to S66 have been performed a third time. If the number of times has not reached the third time (NO in step S67), steps S61 to S66 are performed again. Meanwhile, if the number of times has reached the third time (YES in step S67), the processing is terminated. The third time is set, for example, according to the target film thickness of the silicon oxide film (102). The third time may be one time or two or more times.

[0088] As described above, according to the method for modifying a silicon oxide film according to the sixth embodiment, the method comprises a process of preparing a substrate (100) on which a silicon oxide film (102) is formed and a process of modifying the silicon oxide film (102). The process of modifying the silicon oxide film (102) includes steps S63, S64, and S62. In step S63, the surface of the silicon oxide film (102) is exposed to a plasma (P1) generated from a first gas containing hydrogen gas. In step S64, the surface of the silicon oxide film (102) is exposed to a plasma (P2) generated from a second gas containing argon gas but not hydrogen gas. In step S62, the surface of the silicon oxide film (102) is exposed to a plasma (P3) generated from a third gas containing nitrogen gas. In this case, the leakage current of the silicon oxide film (102) can be reduced, similar to the method for modifying a silicon oxide film according to the first embodiment. That is, the electrical properties of the silicon oxide film (102) can be improved.

[0089] The method for modifying a silicon oxide film according to the 6th embodiment can be carried out using a processing system (PS) according to the 1st embodiment, just like the method for modifying a silicon oxide film according to the 1st embodiment.

[0090] [Example]

[0091] (Example 1)

[0092] In Example 1, the process of forming a silicon oxide film on a substrate and the process of modifying the silicon oxide film were repeated three times in this order. In the process of forming the silicon oxide film and the process of modifying the silicon oxide film, the substrate temperature was fixed at 130°C.

[0093] In the process of forming a silicon oxide film, a silicon oxide film was formed on a substrate by supplying TMA gas to the substrate and then supplying TPSOL gas. TMA gas is an example of a metal catalyst gas. TPSOL gas is an example of a silanol-containing gas.

[0094] In the process of modifying a silicon oxide film, first, a treatment was performed in which the surface of the silicon oxide film was exposed to a plasma generated from hydrogen gas and argon gas, and the surface of the silicon oxide film was exposed to a plasma generated from argon gas, and this step was repeated three times in this order. Subsequently, a treatment was performed in which the surface of the silicon oxide film was exposed to a plasma generated from nitrogen gas, argon gas, and hydrogen gas. Hereinafter, the treatment in which the surface of the silicon oxide film was exposed to a plasma generated from hydrogen gas and argon gas, and the surface of the silicon oxide film was exposed to a plasma generated from argon gas, and this step was repeated in this order is also called cyclic plasma treatment. The treatment of exposing the surface of the silicon oxide film to a plasma generated from nitrogen gas, argon gas, and hydrogen gas is also called nitrogen plasma treatment.

[0095] In the nitrogen plasma treatment, the time per cycle was fixed at 15 seconds. In the nitrogen plasma treatment, while the flow rate of argon gas was fixed at 3000 sccm and the total flow rate of nitrogen gas and hydrogen gas was fixed at 2000 sccm, the ratio of the flow rates of nitrogen gas and hydrogen gas was changed by changing the flow rates of nitrogen gas and hydrogen gas.

[0096] Next, the film thickness and leakage current density of the silicon oxide film formed on the substrate were measured. A spectroscopic ellipsometer was used to measure the film thickness. A mercury probe was used to measure the leakage current density. The current density flowing through the silicon oxide film when an electric field of 5 MV / cm and 3 MV / cm was applied to the silicon oxide film was defined as the leakage current density. The electric field was calculated by dividing the applied voltage by the film thickness. The current density was calculated by dividing the measured current at the time of voltage application by the electrode area of ​​the mercury probe.

[0097] Figures 11 and 12 illustrate the leakage current density of a silicon oxide film. Figure 11 shows the leakage current density when an electric field of 5 MV / cm is applied to the silicon oxide film. Figure 12 shows the leakage current density when an electric field of 3 MV / cm is applied to the silicon oxide film. In Figures 11 and 12, the horizontal axis represents the flow rate of nitrogen gas [sccm], and the vertical axis represents the leakage current density of the silicon oxide film [A / cm²]. 2 It represents ].

[0098] As shown in FIG. 11, the leakage current density of the silicon oxide film when the nitrogen gas flow rate in the nitrogen plasma treatment is 0 sccm, 250 sccm, 500 sccm, 1000 sccm, 1500 sccm, and 2000 sccm is 1.1 x 10⁻¹⁰, respectively. -7 A / cm 2 , 2.8X10 -8 A / cm 2 , 2.4X10 -8 A / cm 2 , 3.0Х10 -8 A / cm 2 , 4.5Х10 -8 A / cm 2 , and 2.0X10 -8 A / cm 2 was.

[0099] When the nitrogen gas flow rate in nitrogen plasma treatment is 250 sccm to 2000 sccm, the leakage current density of the silicon oxide film is smaller compared to when the nitrogen gas flow rate in nitrogen plasma treatment is 0 sccm. Based on these results, it can be said that the leakage current of the silicon oxide film can be reduced by performing nitrogen plasma treatment after cyclic plasma treatment.

[0100] When the nitrogen gas flow rate in nitrogen plasma treatment is 250 sccm to 2000 sccm, no significant difference in the leakage current density of the silicon oxide film is found. Based on these results, it can be said that the leakage current of the silicon oxide film can be reduced regardless of the nitrogen gas flow rate in nitrogen plasma treatment.

[0101] As shown in FIG. 12, the leakage current density of the silicon oxide film when the nitrogen gas flow rate in the nitrogen plasma treatment is 0 sccm, 250 sccm, 500 sccm, 1000 sccm, 1500 sccm, and 2000 sccm is 2.3 x 10⁻¹⁰, respectively. -8 A / cm 2 , 1.3X10 -8 A / cm 2 , 1.0Х10 -8 A / cm 2 , 1.1X10 -8 A / cm 2 , 1.8X10 -8 A / cm 2 , and 3.6Х10 -9 A / cm 2 was.

[0102] When the nitrogen gas flow rate in nitrogen plasma treatment is 2000 sccm, the leakage current density of the silicon film is smaller compared to cases where the nitrogen gas flow rate in nitrogen plasma treatment is 250 sccm, 500 sccm, 1000 sccm, and 1500 sccm. Based on these results, it can be said that not including hydrogen gas in nitrogen plasma treatment can reduce the leakage current of the silicon oxide film compared to including hydrogen gas.

[0103] (Example 2)

[0104] In Example 2, the process of forming a silicon oxide film on a substrate and the process of modifying the silicon oxide film were repeated three times in this order. In the process of forming the silicon oxide film and the process of modifying the silicon oxide film, the substrate temperature was fixed at 130°C. The process of forming the silicon oxide film is the same as in Example 1.

[0105] In the process of modifying the silicon oxide film, the silicon oxide film was modified according to conditions 2A to 2E described below.

[0106] <Condition 2A>

[0107] Nitrogen plasma treatment was performed after cyclic plasma treatment.

[0108] <Condition 2B>

[0109] Cyclic plasma treatment was performed after nitrogen plasma treatment.

[0110] <Condition 2C>

[0111] Nitrogen plasma treatment was not performed, and only cyclic plasma treatment was performed.

[0112] <Condition 2D>

[0113] Only nitrogen plasma treatment was performed without cyclic plasma treatment.

[0114] <Condition 2E>

[0115] Cyclic plasma treatment and nitrogen plasma treatment were not performed.

[0116] In conditions 2A to 2E, the flow rate of nitrogen gas in the nitrogen plasma treatment was set to 250 sccm, the flow rate of hydrogen gas to 1750 sccm, and the flow rate of argon gas to 3000 sccm.

[0117] Next, the film thickness and leakage current density of the silicon oxide film formed on the substrate were measured. A spectroscopic ellipsometer was used to measure the film thickness. A mercury probe was used to measure the leakage current density. The leakage current density was defined as the current density flowing through the silicon oxide film when an electric field of 5 MV / cm was applied to the silicon oxide film. The electric field was calculated by dividing the applied voltage by the film thickness. The current density was calculated by dividing the measured current at the time of voltage application by the electrode area of ​​the mercury probe.

[0118] Figure 13 is a diagram showing the leakage current density of a silicon oxide film. Figure 13 shows the leakage current density of a silicon oxide film when the conditions for modifying the silicon oxide film are changed. In Figure 13, the leakage current density [A / cm²] of the silicon oxide film when the silicon oxide film is modified under conditions 2A, 2B, 2C, 2D, and 2E, in order from left to right. 2 It represents ].

[0119] As shown in FIG. 13, the leakage current density of the silicon oxide film when modified under conditions 2A, 2B, 2C, 2D, and 2E is 2.8×10⁻¹⁰, respectively. -8 A / cm 2 , 3.3Х10 -8 A / cm 2 , 6.4X10 -7 A / cm 2 , 6.9Х10 -6 A / cm 2 , and 7.3Х10 -6 A / cm 2 was.

[0120] Conditions 2A and 2B show a significant decrease in the leakage current density of the silicon oxide film compared to Condition 2E, whereas Conditions 2C and 2D show a smaller decrease in the leakage current density of the silicon oxide film compared to Condition 2E. Based on these results, it can be said that by performing cyclic plasma treatment and nitrogen plasma treatment on the silicon oxide film, the leakage current of the silicon oxide film can be reduced compared to the case where only one of the cyclic plasma treatment and nitrogen plasma treatment is performed on the silicon oxide film.

[0121] There is almost no difference in the leakage current density of the silicon oxide film between condition 2A and condition 2B. Based on these results, it can be said that even when nitrogen plasma treatment is performed before cyclic plasma treatment, the leakage current of the silicon oxide film can be reduced to the same extent as when nitrogen plasma treatment is performed after cyclic plasma treatment.

[0122] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The embodiments may be omitted, substituted, or modified in various forms without departing from the appended claims and their intent.

[0123] In the above embodiments, the case of forming a silicon oxide film using a metal catalyst gas and a silanol-containing gas has been described, but the present disclosure is not limited thereto. For example, a silicon oxide film may be formed using a silicon-containing gas and an oxidizing agent.

[0124] In the above embodiments, the case where the hydrogen-containing gas is hydrogen gas, the nitrogen-containing gas is nitrogen gas, and the inert gas is argon gas has been described, but the present disclosure is not limited thereto. The nitrogen-containing gas may be ammonia gas. The inert gas may be a noble gas other than argon gas, for example, helium gas.

[0125] This application claims priority based on Japanese Patent Application No. 2024-005793 filed on January 18, 2024, and incorporates the entire contents of said application into this application. Explanation of the symbols

[0126] 100 substrate 102 silicon oxide film P1, P2, P3 plasma

Claims

Claim 1 A method for modifying a silicon oxide film, comprising a process of preparing a substrate on which a silicon oxide film is formed, and a process of modifying the silicon oxide film, wherein the process of modifying the silicon oxide film comprises: (a) a process of exposing the surface of the silicon oxide film to a plasma generated from a first gas containing a hydrogen-containing gas; (b) a process of exposing the surface of the silicon oxide film to a plasma generated from a second gas containing an inert gas and not containing a hydrogen-containing gas; and (c) a process of exposing the surface of the silicon oxide film to a plasma generated from a third gas containing a nitrogen-containing gas. Claim 2 A method for modifying a silicon oxide film according to claim 1, wherein the process (a), the process (b), and the process (c) are carried out in this order. Claim 3 A method for modifying a silicon oxide film according to claim 1, wherein the process for modifying the silicon oxide film comprises (d) a process of repeating the process (a) and the process (b). Claim 4 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the process for modifying the silicon oxide film comprises (e) a process of repeating the process (a), the process (b), and the process (c). Claim 5 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the plasma is maintained when switching from process (a) to process (b) or when switching from process (b) to process (a). Claim 6 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the plasma is stopped when switching from process (a) to process (b) or when switching from process (b) to process (a). Claim 7 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the plasma is maintained when switching from process (b) to process (c) or when switching from process (c) to process (b). Claim 8 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the plasma is stopped when switching from process (b) to process (c) or when switching from process (c) to process (b). Claim 9 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the first gas comprises the inert gas. Claim 10 A method for modifying a silicon oxide film according to claim 9, wherein the supply of the inert gas is maintained when switching from process (a) to process (b) or from process (b) to process (a). Claim 11 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the third gas comprises the inert gas. Claim 12 A method for modifying a silicon oxide film according to claim 11, wherein the third gas comprises the hydrogen-containing gas. Claim 13 A method for modifying a silicon oxide film according to claim 11, wherein the third gas does not include the hydrogen-containing gas. Claim 14 A method for modifying a silicon oxide film according to claim 12, wherein the flow rate ratio of the nitrogen-containing gas included in the third gas is 5% or more and 40% or less. Claim 15 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the hydrogen-containing gas is hydrogen gas, the inert gas is argon gas, and the nitrogen-containing gas is nitrogen gas. Claim 16 A method for modifying a silicon oxide film according to any one of claims 1 to 3, wherein the preparing process comprises: a process of supplying a metal catalyst gas to the substrate to adsorb the metal catalyst gas onto the surface of the substrate; and a process of supplying a silanol-containing gas to the substrate to react the silanol-containing gas with the metal catalyst gas adsorbed onto the surface to form the silicon oxide film. Claim 17 A method for modifying a silicon oxide film according to claim 16, wherein the above-described preparation process comprises a process of repeating the process of adsorbing the metal catalyst gas and the process of forming the silicon oxide film. Claim 18 A method for modifying a silicon oxide film according to claim 17, comprising a process of repeating the process of adsorbing the metal catalyst gas, the process of forming the silicon oxide film, and the process of modifying the silicon oxide film. Claim 19 A method for modifying a silicon oxide film according to claim 16, wherein the process of modifying the silicon oxide film is carried out at a higher temperature than the process of adsorbing the metal catalyst gas and the process of forming the silicon oxide film. Claim 20 A substrate processing apparatus comprising a processing vessel, a gas supply unit for supplying gas into the processing vessel, and a control unit, wherein the control unit is configured to control the gas supply unit to perform a process of preparing a substrate having a silicon oxide film formed thereon and a process of modifying the silicon oxide film, and wherein the process of modifying the silicon oxide film comprises: (a) a process of exposing the surface of the silicon oxide film to a plasma generated from a first gas containing a hydrogen-containing gas; (b) a process of exposing the surface of the silicon oxide film to a plasma generated from a second gas containing an inert gas and not containing a hydrogen-containing gas; and (c) a process of exposing the surface of the silicon oxide film to a plasma generated from a third gas containing a nitrogen-containing gas.

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