Film forming method and film forming system

Abstract

To provide a deposition method and a deposition system capable of forming oxide films with high pressure resistance performance.SOLUTION: A deposition method includes a natural oxide film removal process in which a natural oxide film formed on a substrate W1 formed from SiC is removed by a dry etching method, and an oxide film growth process in which after the natural oxide film removal process, the temperature of the substrate W1 is maintained at 200°C or lower under a vacuum environment higher than a preset standard vacuum level while an oxide film is grown by a chemical vapor deposition method.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a film formation method and a film formation system. [Background technology]

[0002] A method for manufacturing a semiconductor device including a semiconductor layer made of SiC, a body region formed in a surface portion of the semiconductor layer, a source region formed in a surface portion of the body region, a drain region formed on the back side of the semiconductor layer with respect to the body region, a gate trench penetrating the source region and the body region from the surface of the semiconductor layer, a gate insulating film formed on the inner surface of the gate trench, and a gate electrode embedded in the gate trench via the gate insulating film has been proposed (see, for example, Patent Document 1). Here, the gate insulating film is formed by oxidizing the inner surface of the gate trench by a thermal oxidation method in which a SiC substrate in which a gate trench is formed is exposed to a gas containing nitrogen and oxygen while being maintained at 1300° C. for 200 to 240 minutes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-91840 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a method for forming a gate insulating film using a thermal oxidation method such as the semiconductor device manufacturing method described in Patent Document 1, oxygen in the gas reacts with carbon released from the SiC substrate to generate CO2. The generated CO2 is then taken into the gate insulating film via crystal defects present in the SiC, which may result in a decrease in the breakdown voltage of the gate insulating film.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a film forming method and a film forming system capable of forming an oxide film having high voltage resistance. [Means for solving the problem]

[0006] In order to achieve the above object, a film forming method according to the present invention includes: a native oxide film removing step of removing a native oxide film formed on a substrate made of SiC by a dry etching method; an oxide film growing step of growing an oxide film by chemical vapor deposition while maintaining the temperature of the substrate at 200° C. or less in an environment with a vacuum degree higher than a preset reference vacuum degree after the native oxide film removing step; 、 a nitrogen plasma exposure step of exposing the oxide film to plasma containing nitrogen radicals while maintaining the temperature of the substrate at 200° C. or less in an environment with a vacuum degree higher than the reference vacuum degree after the oxide film growth step; a heat treatment step of nitriding the oxide film to form an oxynitride film by maintaining the temperature of the substrate at 1000° C. or higher in a nitrogen gas atmosphere while maintaining an environment of a vacuum degree higher than the reference vacuum degree after the nitrogen plasma exposure step; , including. Effect of the Invention

[0007] According to the present invention, in the oxide film growing step, an oxide film is grown by chemical vapor deposition while maintaining the substrate temperature at 200° C. or less in an environment with a vacuum degree higher than a preset reference vacuum degree. This makes it possible to suppress the reaction between carbon released from the substrate and oxygen to generate CO2, thereby suppressing a decrease in the breakdown voltage of the oxide film caused by the incorporation of CO2 into the oxide film. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a film forming system according to an embodiment of the present invention. [Diagram 2] 1 is a schematic configuration diagram of a film forming apparatus according to an embodiment; [Diagram 3] 1 is a schematic configuration diagram of a heat treatment apparatus according to an embodiment; [Figure 4] 2 is a flowchart showing a flow of a film forming method according to an embodiment. [Diagram 5]FIG. 1A is a schematic diagram for explaining an oxide film removal process in accordance with an embodiment; FIG. 1B is a schematic diagram for explaining an oxide film growth process in accordance with an embodiment; and FIG. 1C is a schematic diagram for explaining a nitrogen plasma exposure process in accordance with an embodiment. [Figure 6] 5A to 5C are schematic diagrams for explaining a heat treatment step according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of the present invention will be described in detail below with reference to the drawings. The film forming method according to the present embodiment includes a natural oxide film removing step of removing a natural oxide film formed on a substrate made of SiC by dry etching, and an oxide film growing step of growing an oxide film by chemical vapor deposition while maintaining the temperature of the substrate at 200° C. or less in an environment having a vacuum degree higher than a preset reference vacuum degree in which oxygen is present after the natural oxide film removing step.

[0010] As shown in FIG. 1, the film forming system according to the present embodiment includes an introduction port 811 into which a substrate W1 before film formation is introduced, an unloading port 812, a preparation chamber 822, transport devices 821 and 84, a cleaning device 3, a film forming device 1, a heat treatment device 2, and load lock units 831 and 832. The transport device 821 includes a transport robot 8211 having an arm 8211a that holds the substrate W1 at its tip, and a robot transport unit 8212 that moves the transport robot 8211. The robot transport unit 8212 can move the transport robot 8211 along the arrangement direction of the introduction port 811 and the unloading port 812 in the preparation chamber 822. The transport robot 8211 can change the direction of the arm 8211a by rotating. The cleaning device 3 is disposed in the preparation chamber 822, and cleans the substrate W1 by rotating the substrate W1 while discharging a cleaning liquid toward the substrate W1 transported to the cleaning device 3. Furthermore, the cleaning apparatus 3 spin-dries the substrate W1 by rotating the substrate W1 while stopping the discharge of the cleaning liquid onto the substrate W1.

[0011] The load lock units 831 and 832 each include a load lock chamber 8313 and 8323, a vacuum pump (not shown) that exhausts gas from the load lock chambers 8313 and 8323 through an exhaust pipe communicating with the inside of the load lock chambers 8313 and 8323, and an exhaust valve (not shown) inserted in the exhaust pipe. With the vacuum pump operating, the load lock units 831 and 832 open the exhaust valve to exhaust gas from the load lock chambers 8313 and 8323, thereby reducing the pressure inside the load lock chambers 8313 and 8323. The load lock sections 831, 832 also include vacuum gates 8311, 8321 arranged on the preparation chamber 822 side in the load lock chambers 8313, 8323, vacuum gates 8312, 8322 arranged on the transport device 84 side in the load lock chambers 8312, 8322, and gate driving sections (not shown) that drive the vacuum gates 8311, 8312, 8321, 8322 to open and close.

[0012] The transfer device 84 includes a transfer chamber 842, an exhaust pipe (not shown) communicating with the inside of the transfer chamber 842, a vacuum pump (not shown) for discharging gas from the transfer chamber 842 through the exhaust pipe, an exhaust valve (not shown) inserted in the exhaust pipe, and a transfer robot 841 for transporting the substrate W1. The transfer device 84 maintains the inside of the transfer chamber 842 in a reduced pressure state by discharging gas from the transfer chamber 842 by opening the exhaust valve while the vacuum pump is in operation. The transfer chamber 842 is connected to the film forming apparatus 1 via a vacuum gate 851, and is connected to the heat treatment apparatus 2 via a vacuum gate 852. The vacuum gates 851 and 852 are in an open state when the transfer robot 841 transports the substrate W1 to the film forming apparatus 1 and the heat treatment apparatus 2, respectively. The transfer robot 841 has an arm 841a for holding the substrate W1 at its tip, and can change the direction of the tip of the arm 841a by rotating.

[0013] The film forming apparatus 1 is a so-called inductively coupled plasma type CVD apparatus, and includes a chamber 101, a stage 190, a high frequency application unit 102, a bias application unit 106, raw material gas supply units 121, 122, 123, and an etchant gas supply unit 111, as shown in FIG. 2. The film forming apparatus 1 forms an oxide film such as SiO2 or an oxynitride insulating film such as SiON on the upper surface side of a substrate W1 placed in the chamber 101. Here, the substrate W1 is a SiC substrate. The chamber 101 is a first chamber to which a vacuum pump 181 is attached via an exhaust pipe 182 communicating with the inside of the chamber 101. When the vacuum pump 181 operates, the gas in the chamber 101 is exhausted through the exhaust pipe 182, and the inside of the chamber 101 is reduced in pressure. In addition, a dielectric window 141 is attached to the upper part of the chamber 101. Furthermore, an opening (not shown) is provided in a portion of the peripheral wall of chamber 101 for transferring substrate W1 between the chamber 101 and the transfer chamber 842 of the transfer device 84, and the opening of chamber 101 and the transfer chamber 842 are connected via a vacuum gate 851.

[0014] The stage 190 is a first stage disposed in the chamber 101 and supporting the substrate W1 on which an insulating film is to be formed. The stage 190 is made of a metal such as Al, SUS, or Cu. A heater 191 for heating the substrate W1 is embedded in the stage 190.

[0015] The raw material gas supply units 121, 122, and 123 are gas supply units that introduce raw material gases that are the basis of an insulating film into the chamber 101. Examples of raw material gases include SiH4, O2, and N2. The raw material gas supply unit 121 has, for example, a gas storage unit 121a that stores SiH4 gas, a supply pipe 121b to which the SiH4 gas is supplied from the gas storage unit 121a, and a flow rate control valve 121c for controlling the flow rate of the raw material gas flowing through the supply pipe 121b. The raw material gas supply unit 122 has, for example, a gas storage unit 122a that stores O2 gas, a supply pipe 122b to which the O2 gas is supplied from the gas storage unit 121a, and a flow rate control valve 122c for controlling the flow rate of the O2 gas flowing through the supply pipe 122b. The raw material gas supply unit 123 has, for example, a gas storage unit 123a for storing N2 gas, a supply pipe 123b to which N2 gas is supplied from the gas storage unit 123a, and a flow rate control valve 123c for controlling the flow rate of the N2 gas flowing through the supply pipe 123b. The etchant gas supply unit 111 supplies tetrafluoromethane (CF4) as an etchant gas into the chamber 101. The etchant gas supply unit 111 has a gas storage unit 111a for storing CF4 gas, and a supply pipe 111b for supplying the CF4 gas from the gas storage unit 111a into the chamber 101. The etchant gas supply unit 111 also has a flow rate control valve 111c for controlling the flow rate of the CF4 gas flowing through the supply pipe 111b.

[0016] The high frequency application unit 102 includes a high frequency generating source 102a that generates high frequency power, a matching box 102b, and an induction coil 102c that is disposed outside the chamber 101 and faces a dielectric window 141 of the chamber 101. The induction coil 102c is preferably shaped to form a magnetic field of uniform strength in the chamber 101, and may have a shape such as that described in Japanese Patent Application Laid-Open No. 2005-228738 previously disclosed by the applicant of the present application. The high frequency application unit 102 can generate a high frequency magnetic field of uniform strength in a direction parallel to the coil surface of the induction coil 102c. The high frequency application unit 102 applies an electromagnetic field of high frequency (for example, a frequency of 13.56 MHz) to the source gas or etchant gas supplied into the chamber 101, thereby generating a plasma PLM in the chamber 101.

[0017] The bias application unit 106 applies a high-frequency bias to the substrate W1 supported by the stage 190. The bias application unit 106 applies a high-frequency voltage (e.g., a high-frequency voltage with a frequency of 13.56 MHz) that oscillates between 0 V and a negative voltage of −2000 V to the stage 190. The bias application unit 106 has a high-frequency generation source 106a and a matching box 106b.

[0018] As shown in FIG. 3, the heat treatment apparatus 2 includes a chamber 201, a stage 290, a lamp heater 202, and a nitrogen gas supply unit 221. The chamber 201 is a second chamber to which a vacuum pump 281 is attached via an exhaust pipe 282 communicating with the inside of the chamber 201. When the vacuum pump 281 operates, gas in the chamber 201 is exhausted through the exhaust pipe 282, and the inside of the chamber 201 is reduced in pressure. A window 241 made of a light-transmitting material is attached to the upper part of the chamber 201. Furthermore, an opening (not shown) is provided in a part of the peripheral wall of the chamber 201 for inserting and removing the substrate W1 between the chamber 201 and a transfer chamber 842 of the transfer device 84, and the opening of the chamber 201 and the transfer chamber 842 are connected via a vacuum gate 852.

[0019] The stage 290 is a second stage that is disposed in the chamber 201 and supports the substrate W1 on which an insulating film is to be formed. The stage 290 is made of a metal such as Al, SUS, Cu, etc. The stage 290 is rotated about the rotation axis J2 by ​​a rotation drive unit 293 that rotates the stage 290 about the rotation axis J2.

[0020] The nitrogen gas supply unit 221 introduces nitrogen gas into the chamber 201. The nitrogen gas supply unit 221 has a gas storage unit 221a that stores N2 gas, a supply pipe 221b to which N2 gas is supplied from the gas storage unit 221a, and a flow rate control valve 221c for controlling the flow rate of the N2 gas flowing through the supply pipe 221b.

[0021] The lamp heaters 202 are, for example, tubular halogen lamp heaters, and a plurality of lamp heaters 202 are disposed facing each other on the side opposite to the inside of the chamber 201 relative to the window 241 .

[0022] Next, the film forming method according to the present embodiment will be described with reference to FIGS. 4 to 6. First, as shown in FIG. 4, the substrate W1 made of SiC is introduced into the introduction port 811 (step S1), and the transport device 821 takes out the substrate W1 introduced into the introduction port 811 and transports it to the cleaning device 3 (step S2). Here, the transport robot 8211 of the transport device 821 takes out the substrate W1 from the introduction port 811, and then rotates while holding the substrate W1 so that the tip of the arm 8211a faces the cleaning device 3. Next, the robot transport unit 8212 of the transport device 821 moves the transport robot 8211 holding the substrate W1 to the vicinity of the cleaning device 3 in the preparation room 822. Then, the transport robot 8211 extends the arm 8211a to transfer the substrate W1 held at the tip of the arm 8211a to the cleaning device 3. After that, the transport robot 8211 retracts the arm 8211a.

[0023] Next, the cleaning device 3 executes a cleaning process in which cleaning water is sprayed onto the substrate W1 to clean it (step S3). Here, the cleaning device 3 rotates the stage on which the substrate W1 is placed while spraying the cleaning water onto the substrate W1, thereby cleaning the entire surface of the substrate W1. This removes foreign matter adhering to the substrate W1. Next, the cleaning device 3 stops spraying the cleaning water, and then rotates the stage to spin-dry the substrate W1, completing the cleaning process.

[0024] Next, the robot transport unit 8212 of the transport device 821 transports the substrate W1 for which the water cleaning process has been completed from the cleaning device 3 to either one of the load lock units 831, 832 (step S4). Here, the transport robot 8211 of the transport device 821 again extends the arm 8211a to hold the substrate W1 at the tip of the arm 8211a, and then contracts the arm 8211a to remove the substrate W1 from the cleaning device 3. Next, the robot transport unit 8212 of the transport device 821 moves the transport robot 8211 to a position facing the vacuum gates 8311, 8321 of either one of the load lock units 831, 832 in the preparation chamber 822. Then, when one of the load lock units 831 and 832 in which the transfer robot 8211 is disposed opens the vacuum gates 8311 and 8121, the transfer robot 8211 rotates so that the tip of the arm 8211a faces the load lock units 831 and 832 while holding the substrate W1. Then, the transfer robot 8211 extends the arm 8211a to insert the tip of the arm 8211a into the load lock chambers 8313 and 8323. Then, the transfer robot 8211 retracts the arm 8211a when the transfer of the substrate W1 into the load lock chambers 8313 and 8323 is completed. Then, the load lock units 831 and 832 close the vacuum gates 8311 and 8321. The load lock units 831 and 832 exhaust gas present in the load lock chambers 8313 and 8323 to reduce the pressure in the load lock chambers 8313 and 8323 until the degree of vacuum in the load lock chambers 8313 and 8323 becomes substantially the same as the degree of vacuum in the transfer chamber 842 of the transfer device 84.

[0025] Thereafter, the transfer device 84 transfers the substrate W1 arranged in the load lock chambers 8313, 8323 of the load lock units 831, 832 to the film forming device 1 (step S5). Here, when the vacuum in the load lock chambers 8313, 8323 of the load lock units 831, 832 is reduced to approximately the same as the vacuum in the transfer chamber 842, the vacuum gates 8312, 8322 of the load lock units 831, 832 are opened. Next, the transfer robot 841 of the transfer device 84 turns so that the tip of the arm 841a faces the load lock units 831, 832. Next, the transfer robot 841 extends the arm 841a to insert the tip of the arm 841a into the load lock chambers 8313, 8323. Then, the substrate W1 is transferred from the load lock chambers 8313, 8323 to the tip of the arm 841a. Thereafter, when the transfer of the substrate W1 to the tip of the arm 841a is completed, the transfer robot 841 retracts the arm 841a. Then, the load lock units 831 and 832 close the vacuum gates 8312 and 8322. Next, the transfer robot 841 turns so that the tip of the arm 841a faces the film forming apparatus 1. Then, when the transfer device 84 opens the vacuum gate 851, the transfer robot 841 extends the arm 841a to insert the tip of the arm 841a into the chamber 101 of the film forming apparatus 1. Then, the substrate W1 is transferred from the tip of the arm 841a onto the stage 190 in the chamber 101. Thereafter, when the transfer of the substrate W1 to the stage 190 is completed, the transfer robot 841 retracts the arm 841a. Then, the transfer device 84 closes the vacuum gate 851.

[0026] Returning to FIG. 4, next, the film forming apparatus 1 performs a natural oxide film removal process in which the natural oxide film formed from SiO2 is removed by dry etching while the bias application unit 106 applies a high-frequency voltage to the substrate W1 (step S6). The etchant gas used in this natural oxide film removal process is CF4 gas. O2 gas is also used in the natural oxide film removal process. In the etching process, the flow rate ratio of CF4 gas and O2 gas supplied to the chamber 101 is set to 100:7. Here, the high-frequency application unit 102 applies high frequency with CF4 gas and O2 gas introduced into the chamber 101, and converts CF4 gas into CF + A plasma PLM0, which is a first plasma containing radicals, is generated, and reactive ion etching is performed by exposing the native oxide film to the generated plasma PLM0, thereby etching the native oxide film.

[0027] Returning to FIG. 4, the film forming apparatus 1 then performs an oxide film growth process in which an oxide film is grown by a plasma CVD (Chemical Vapor Deposition) method while maintaining the temperature of the substrate W1 at 200° C. or less in an environment with a vacuum degree higher than a preset reference vacuum degree in which oxygen is present (step S7). The raw material gases used in this oxide film growth process are SiH4 gas, O2 gas, and N2 gas. The flow rate ratio of SiH4 gas, O2 gas, and N2 gas supplied to the chamber 101 in the oxide film growth process is set to 1:2:20. The temperature of the substrate W1 in the oxide film growth process is set to 200° C. or less. Here, the film forming apparatus 1 grows a SiO2 film on the substrate W1 while the bias application unit 106 applies a high-frequency voltage to the substrate W1. Specifically, the high frequency applying unit 102 applies high frequency waves in a state where SiH4 gas, O2 gas, and N2 gas are introduced into the chamber 101, and generates a plasma PLM1, which is a second plasma containing active species such as higher order silane, as shown in Fig. 5(B), and grows a SiO2 film L1 by exposing the surface of the substrate W1 to the generated plasma PLM1. In addition, the film forming apparatus 1 sets the thickness TH1 of the SiO2 film L1 formed in this oxide film growth process to, for example, a thickness of 50 nm or more and 75 nm or less.

[0028] Returning to FIG. 4, the film forming apparatus 1 then performs a nitrogen plasma exposure process in which the SiO2 film is exposed to plasma containing nitrogen radicals while maintaining the temperature of the substrate W1 at 200° C. or less in an environment with a vacuum degree higher than the above-mentioned reference vacuum degree (step S8). The raw material gas used in this nitrogen plasma exposure process is N2 gas. The temperature of the substrate W1 in the nitrogen plasma exposure process is set to 200° C. or less. Here, the film forming apparatus 1 exposes the SiO2 film formed on the substrate W1 to nitrogen plasma while the bias application unit 106 applies a high-frequency voltage to the substrate W1. Specifically, the high-frequency application unit 102 applies a high-frequency voltage with N2 gas introduced into the chamber 101 to generate a third plasma PLM2 containing nitrogen radicals as shown in FIG. 5(C), and exposes the SiO2 film formed on the substrate W1 to the generated plasma PLM2. This causes nitrogen atoms to be doped into the SiO2 film.

[0029] Returning to FIG. 4, the transfer device 84 then transfers the substrate W1 that has been subjected to the nitrogen plasma exposure process from the film forming apparatus 1 to the heat treatment apparatus 2 (step S9). Here, when the transfer device 84 opens the vacuum gate 851, the transfer robot 841 extends the arm 841a to insert the tip of the arm 841a into the chamber 101 of the film forming apparatus 1. Then, the substrate W1 on which the SiO2 film has been formed is transferred from the stage 190 in the chamber 101 to the tip of the arm 841a. After that, when the transfer of the substrate W1 to the stage 190 is completed, the transfer robot 841 contracts the arm 841a. Then, the transfer device 84 closes the vacuum gate 851. Next, the transfer robot 841 turns so that the tip of the arm 841a faces the heat treatment apparatus 2 side. Next, when the transfer device 84 opens the vacuum gate 852, the transfer robot 841 extends the arm 841a to insert the tip of the arm 841a into the chamber 201 of the heat treatment device 2. Then, the substrate W1 is transferred from the tip of the arm 841a onto the stage 290 in the chamber 201. Thereafter, when the transfer of the substrate W1 onto the stage 290 is completed, the transfer robot 841 retracts the arm 841a. Then, the transfer device 84 closes the vacuum gate 852.

[0030] Next, the heat treatment device 2 performs a heat treatment process to nitride the SiO2 film to form a SiON film by maintaining the temperature of the substrate W1 at 1000°C or higher in a nitrogen gas atmosphere while maintaining an environment of a vacuum degree higher than the reference vacuum degree (step S10). Here, the heat treatment device 2 introduces N2 gas into the chamber 201 to create an N2 gas atmosphere in the chamber 201. Then, the heat treatment device 2 rotates the stage 290 around the rotation axis J2 shown in FIG. 3, and irradiates the SiO2 film formed on the substrate W1 with light Li1 emitted from the lamp heater 202, as shown in FIG. 6, to heat the substrate W1 and the SiO2 film with the radiant heat. As a result, the nitrogen atoms doped in the SiO2 film are activated to form a SiON film.

[0031] Returning to FIG. 4, the transfer device 84 then transfers the substrate W1 that has been subjected to the heat treatment process from the heat treatment device 2 to one of the load lock units 831 and 832 again (step S11). Here, when the transfer device 84 opens the vacuum gate 852, the transfer robot 841 extends the arm 841a to insert the tip of the arm 841a into the chamber 201 of the heat treatment device 2. Then, the substrate W1 that has been subjected to the heat treatment process is transferred from the stage 290 in the chamber 201 to the tip of the arm 841a. Then, when the transfer of the substrate W1 to the stage 290 is completed, the transfer robot 841 contracts the arm 841a. Then, the transfer device 84 closes the vacuum gate 852. Next, the transfer robot 841 turns so that the tip of the arm 841a faces one of the load lock units 831 and 832. Next, when the load lock units 831 and 832 open the vacuum gates 8312 and 8322, the transfer robot 841 extends the arm 841a to insert the tip of the arm 841a into the load lock chambers 8313 and 8323. Then, the substrate W1 is transferred from the tip of the arm 841a into the load lock chambers 8313 and 8323. Thereafter, when the transfer of the substrate W1 into the load lock chambers 8313 and 8323 is completed, the transfer robot 841 retracts the arm 841a. Then, the load lock units 831 and 832 close the vacuum gates 8312 and 8322.

[0032] Next, the transfer device 821 transfers the substrate W1 arranged in the load lock chambers 8313, 8323 to the take-out port 812 (step S12). Here, first, the load lock units 831, 832 open the load lock chambers 8313, 8323 to the atmosphere by introducing outside air into the load lock chambers 8313, 8323 inside which the substrate W1 is arranged, and then open the vacuum gates 8311, 8321. Next, the robot transfer unit 8212 of the transfer device 821 moves the transfer robot 8211 to a position in the preparation chamber 822 facing the vacuum gates 8311, 8321 of either one of the load lock units 831, 832 that stores the substrate W1. Then, when one of the load lock units 831 and 832 in which the transfer robot 8211 is disposed opens the vacuum gates 8311 and 8121, the transfer robot 8211 rotates so that the tip of the arm 8211a faces the load lock units 831 and 832. After that, the transfer robot 8211 extends the arm 8211a to insert the tip of the arm 8211a into the load lock chambers 8313 and 8323. Then, the substrate W1 is transferred from the inside of the load lock chambers 8313 and 8323 to the tip of the arm 8211a. Next, when the transfer of the substrate W1 into the load lock chambers 8313 and 8323 is completed, the transfer robot 8211 contracts the arm 8211a, and the load lock units 831 and 832 close the vacuum gates 8311 and 8321. Next, the robot transport unit 8212 moves the transport robot 8211 to a position facing the take-out port 812 in the preparation chamber 822, and the transport robot 8211 turns so that the tip of the arm 8211a faces the take-out port 812. Thereafter, the transport robot 8211 extends the arm 8211a to transfer the substrate W1 held at the tip of the arm 8211a to the take-out port 812.

[0033] As described above, according to the film forming method of the present embodiment, in the oxide film growing step, a SiO2 film is grown by plasma CVD while maintaining the temperature of the substrate W1 at 200° C. or less in an environment in which oxygen is present and the vacuum degree is higher than a preset reference vacuum degree. This makes it possible to suppress the reaction of carbon desorbed from the substrate W1 with oxygen to generate CO2, thereby suppressing a decrease in the breakdown voltage of the oxide film caused by the incorporation of CO2 into the oxide film.

[0034] In the film formation direction according to the present embodiment, after the oxide film growth step, the oxide film is exposed to plasma containing nitrogen radicals while maintaining the temperature of the substrate W1 at 200° C. or lower in an environment with a degree of vacuum higher than the reference degree of vacuum, and then the temperature of the substrate W1 is maintained at 1000° C. or higher in a nitrogen gas atmosphere while maintaining the environment with a degree of vacuum higher than the reference degree of vacuum, thereby nitrifying the oxide film L1 to form an oxynitride film. This makes it possible to suppress the release of nitrogen in the oxynitride film after the nitriding process of the oxide film L1.

[0035] Although the embodiment of the present invention has been described above, the present invention is not limited to the configuration of the above-mentioned embodiment. For example, other types of films such as TiON film, AlON film, etc. may be formed on the substrate W1.

[0036] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these. The present invention includes appropriate combinations of the embodiments and modifications, and appropriate modifications thereto. [Industrial Applicability]

[0037] The present invention is suitable for manufacturing electronic devices such as MEMS (Micro Electron Mechanical Systems) and MOS-FETs (Metal-Oxide-Semiconductor Field-Effect-Transistors). [Explanation of symbols]

[0038] 1: film forming apparatus, 2: heat treatment apparatus, 3: cleaning apparatus, 84, 821: transfer apparatus, 101, 201: chamber, 102: high frequency application unit, 102a, 106a: high frequency generation source, 102b, 106b: matching box, 102c: induction coil, 106: bias application unit, 190, 290: stage, 111: etchant gas supply unit, 111a, 121a, 122a, 123a, 221a: gas storage unit, 111b, 121b, 122b, 123b, 221b: supply pipe, 111c, 121c, 122c, 123c, 221c: flow rate control valve, 121, 122, 123: raw material Gas supply unit, 141: dielectric window, 181: vacuum pump, 182: exhaust pipe, 191: heater, 202: lamp heater, 221: nitrogen gas supply unit, 293: rotation drive unit, 811: introduction port, 812: removal port, 822: preparation chamber, 831, 832: load lock unit, 841, 8211: transfer robot, 842: transfer chamber, 851, 852, 8311, 8312, 8321, 8322: vacuum gate, 8212: robot transfer unit, 8313, 8323: load lock chamber, L1: SiO2 film, PLM0, PLM1, PLM2: plasma, W1: substrate

Claims

1. a native oxide film removing step of removing a native oxide film formed on a substrate made of SiC by a dry etching method; an oxide film growing step of growing an oxide film by chemical vapor deposition while maintaining a temperature of the substrate at 200° C. or less in an environment of a vacuum degree higher than a preset reference vacuum degree after the native oxide film removing step; a nitrogen plasma exposure step of exposing the oxide film to plasma containing nitrogen radicals while maintaining a temperature of the substrate at 200° C. or less in an environment with a vacuum degree higher than the reference vacuum degree after the oxide film growth step; and a heat treatment step of, after the nitrogen plasma exposure step, maintaining a temperature of the substrate at 1000° C. or higher in a nitrogen gas atmosphere while maintaining an environment of a vacuum degree higher than the reference vacuum degree, thereby nitriding the oxide film to form an oxynitride film. Film formation method.

2. The oxide film is SiO ２ A membrane, The oxynitride film is a SiON film. The film forming method according to claim 1 .

3. A film forming apparatus for forming an oxide film on a substrate made of SiC; a heat treatment device for forming an oxynitride film by subjecting the oxide film formed by the film forming device to a heat treatment and nitrifying the oxide film, The film forming apparatus includes: A first chamber; and a first stage disposed within the first chamber and supporting the substrate; a source gas supply unit that introduces a source gas that is a base of the oxide film into the first chamber; an etchant gas supply unit that supplies an etchant gas into the first chamber; a high frequency application unit that applies a high frequency electromagnetic field to the source gas or the etchant gas supplied into the first chamber to generate plasma in the first chamber; a bias application unit that applies a high frequency bias to the substrate supported by the first stage, The heat treatment device includes: A second chamber; and a second stage disposed within the second chamber and supporting the substrate; a nitrogen gas supply unit that introduces nitrogen gas into the second chamber; a substrate heating unit for heating the substrate; the film forming apparatus removes a native oxide film formed on the substrate by a dry etching method by supplying the etchant gas from the etchant gas supply unit into the first chamber while the high frequency application unit generates a first plasma in the first chamber and the bias application unit applies a high frequency bias to the substrate, thereafter growing the oxide film by a chemical vapor deposition method while maintaining a temperature of the substrate at 200° C. or less in an environment with a vacuum degree higher than a preset reference vacuum degree by supplying the raw material gas from the raw material gas supply unit into the first chamber while the high frequency application unit generates a second plasma in the first chamber and the bias application unit applies a high frequency bias to the substrate, thereafter exposing the oxide film to the third plasma while maintaining a temperature of the substrate at 200° C. or less in an environment with a vacuum degree higher than the reference vacuum degree by supplying nitrogen gas from the raw material gas supply unit into the first chamber while the high frequency application unit generates a third plasma containing nitrogen radicals in the first chamber and the bias application unit applies a high frequency bias to the substrate; the heat treatment device supplies the nitrogen gas from the nitrogen gas supply unit into the second chamber, while maintaining the inside of the second chamber at a vacuum degree higher than the reference vacuum degree, and maintains a temperature of the substrate on which the oxide film is formed at a temperature of 1000° C. or higher, thereby nitriding the oxide film and forming an oxynitride film. Deposition system.

4. The source gas supply unit supplies SiH ４ Gas and O ２ Supplying gas, The deposition system according to claim 3 .

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