Substrate treatment method and substrate treatment system

Abstract

Provided are a substrate treatment method and a substrate treatment system for forming a silicon oxide film on a substrate having a pattern of recesses and protrusions.　This substrate treatment method is for forming a silicon oxide film and includes: a step for preparing a substrate having a pattern of recesses and protrusions; a step for forming a flowable film containing silicon in recesses of the substrate and on the upper surface of protrusions of the substrate; a first modification step for supplying an oxygen-containing gas to the substrate and modifying the flowable film to form a silicon oxide film; a second modification step for exposing the substrate to a first plasma that does not contain oxygen to modify the silicon oxide film; and a third modification step for exposing the substrate to a second plasma containing oxygen to modify the silicon oxide film.

Description

Substrate processing method and substrate processing system

[0001] The present disclosure relates to a substrate processing method and a substrate processing system.

[0002] Patent Document 1 discloses a method for forming an oxidized dielectric material on a substrate, the method including the steps of forming a dielectric material on the substrate by a flowable CVD process, curing the dielectric material on the substrate, performing a wet oxidation process on the dielectric material on the substrate, and forming an oxidized dielectric material on the substrate.

[0003] Special Publication No. 2013-515355

[0004] In one aspect, the present disclosure provides a substrate processing method and a substrate processing system for forming a silicon oxide film on a substrate having a concavo-convex pattern.

[0005] In order to solve the above-mentioned problems, according to one aspect, there is provided a method for forming a silicon oxide film, comprising: a step of preparing a substrate having a concave-convex pattern; a step of forming a flowable film containing silicon in concave portions and on upper surfaces of convex portions of the substrate; a first modification step of supplying an oxygen-containing gas to the substrate to modify the flowable film to form a silicon oxide film; a second modification step of exposing the substrate to a first plasma not containing oxygen to modify the silicon oxide film; and a third modification step of exposing the substrate to a second plasma containing oxygen to modify the silicon oxide film.

[0006] According to one aspect, it is possible to provide a substrate processing method and a substrate processing system for forming a silicon oxide film on a substrate having a concave-convex pattern.

[0007] 1 is a diagram showing an example of the configuration of a substrate processing system according to an embodiment; 2 is a diagram showing an example of the configuration of a processing device in the substrate processing system; 3 is a diagram showing an example of the configuration of a processing device in the substrate processing system; 4 is a flowchart showing an example of a substrate processing method; 5 is an example of a cross-sectional view of a substrate W in each process; 6 is an example of a schematic view of an oxide film formed on a substrate and a diagram explaining a change in wet etching rate in the depth direction of a silicon oxide film; and 7 is an example of a diagram explaining a change in wet etching rate in the depth direction of a silicon oxide film in each process.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] [Substrate Processing System] First, a substrate processing system will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of a substrate processing system according to one embodiment. In the following description, a substrate processing system having multiple processing chambers will be described as having four processing chambers, but the number of processing chambers is not limited to this. Furthermore, the number of load lock chambers and load ports is not limited to the numbers shown in Fig. 1.

[0010] The substrate processing system includes processing devices 101 to 104 , a vacuum transfer chamber 200 , load lock chambers 301 to 303 , an atmospheric transfer chamber 400 , load ports 501 to 504 , and a control device 600 .

[0011] The processing devices 101 to 104 are connected to the vacuum transfer chamber 200 via gate valves G11 to G14, respectively. The processing devices 101 to 104 are depressurized to a predetermined vacuum atmosphere, and the substrates W are subjected to desired processing therein.

[0012] The processing apparatus 101 is an example of a substrate processing apparatus that performs a process of forming a fluid film on a substrate W (see step S102 in FIG. 4, which will be described later).

[0013] The processing apparatus 102 is an example of a substrate processing apparatus that performs a process (first modifying step) for modifying a fluid film formed on a substrate W (see step S103 in FIG. 4, which will be described later).

[0014] The processing device 103 is an example of a substrate processing device that performs plasma processing (second modification process, third modification process) to modify a fluid film formed on a substrate W (see steps S105 and S106 in Figure 4 described below).

[0015] The processing device 104 may be a substrate processing device that performs any of the above-described processes, or may be a substrate processing device that performs pre-processing or post-processing of the above-described processes, and is not limited thereto.

[0016] An example of the configuration of the processing devices 101 and 102 will be described later with reference to FIG. 2, and an example of the configuration of the processing device 103 will be described later with reference to FIG.

[0017] The interior of the vacuum transfer chamber 200 is depressurized to a predetermined vacuum atmosphere. The vacuum transfer chamber 200 is provided with a transfer mechanism 201 capable of transferring a substrate W in a depressurized state. The transfer mechanism 201 transfers the substrate W to the processing devices 101 to 104 and the load lock chambers 301 to 303. The transfer mechanism 201 has, for example, two transfer arms. However, the number of transfer arms may be one.

[0018] The load lock chambers 301 to 303 are connected to the vacuum transfer chamber 200 via gate valves G21 to G23, respectively, and are connected to the atmospheric transfer chamber 400 via gate valves G31 to G33. The interiors of the load lock chambers 301 to 303 can be switched between an atmospheric atmosphere and a vacuum atmosphere.

[0019] The atmospheric transfer chamber 400 has an atmospheric atmosphere, and for example, a downflow of clean air is formed. An aligner (not shown) that aligns the substrate W is provided inside the atmospheric transfer chamber 400. The atmospheric transfer chamber 400 also has a transfer mechanism 402. The transfer mechanism 402 has, for example, one transfer arm. However, the number of transfer arms may be two or more. The transfer mechanism 402 transfers the substrate W to the load lock chambers 301 to 303, the carriers C of the load ports 501 to 504 (described later), and the aligners.

[0020] The load ports 501 to 504 are provided on the long side walls of the atmospheric transfer chamber 400. Carriers C containing substrates W or empty carriers C are attached to the load ports 501 to 504 via gate valves G41 to G44. As the carriers C, for example, FOUPs (Front Opening Unified Pods) can be used.

[0021] The control device 600 controls each part of the substrate processing system. For example, the control device 600 executes the operations of the processing devices 101 to 104, the operation of the transfer mechanisms 201 and 402, the opening and closing of the gate valves G11 to G14, G21 to G23, G31 to G33, and G41 to G44, and the switching of the atmospheres in the load lock chambers 301 to 303.

[0022] 1 includes a plurality of processing chambers (processing devices 101 to 104), a vacuum transfer chamber (vacuum transfer chamber 200) that vacuum-transfers substrates W between the plurality of processing chambers, and a control device 600. The control device 600 controls each process performed in the processing devices 101 to 104. This allows each process to be performed on the substrate W without exposing the substrate W to the atmosphere while the substrate W is being processed in each processing chamber, that is, without breaking the vacuum.

[0023] [Processing Equipment 101, 102] Next, an example configuration of the processing equipment 101 that performs a process for forming a fluid film (see step S102 in FIG. 4 described later) and the processing equipment 102 that performs a process for modifying the fluid film (see step S103 in FIG. 4 described later) will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example configuration of the processing equipment 101, 102 in a substrate processing system. The processing equipment 101, 102 each have a processing chamber A. In the following description, the processing chamber A of the processing equipment 101 will also be referred to as a first processing chamber, and the processing chamber A of the processing equipment 102 will also be referred to as a second processing chamber.

[0024] The processing device 101 is an apparatus that supplies a processing gas (film forming gas) into the processing chamber A under the control of the control device 120 and performs a process to form a flowable film 520 (see FIG. 5(b) described later) on the substrate W.

[0025] The processing device 102 is a device that supplies a processing gas (modifying gas) into the processing chamber A under the control of the control device 120 and performs a process to modify the fluid film 520 (see Figure 5 (c) described below) formed on the substrate W.

[0026] The processing chamber A is grounded. A mounting table 3 is provided in the processing chamber A for horizontally mounting a substrate W thereon. The mounting table 3 is made of metal and is provided therein with a temperature regulator 4 for regulating the temperature of the substrate W. The mounting table 3 is grounded via the processing chamber A. The temperature regulator 4 is, for example, a heater embedded in the mounting table 3 and is an example of a heating unit.

[0027] An exhaust pipe 5 is connected to the bottom of the processing chamber A, and an exhaust mechanism 6 having a function of controlling the pressure inside the processing chamber A is connected to this exhaust pipe 5. A transfer port 7 through which the substrate W is transferred is formed in the sidewall of the processing chamber A, and the transfer port 7 is opened and closed by a gate valve 8.

[0028] A gas shower head 9 is provided at the top of the processing chamber A so as to face the mounting table 3. The gas shower head 9 has a gas chamber 9a therein and a plurality of gas discharge holes 9b on the bottom surface. The gas shower head 9 is insulated from the ceiling wall of the processing chamber A by an insulating member 35.

[0029] A gas supply unit 55 is connected to the gas shower head 9 via a gas flow path 54. The gas supply unit 55 supplies, for example, a processing gas (a film-forming gas in the processing apparatus 101, and a modifying gas in the processing apparatus 102). It may also supply an inert gas as a carrier gas, a dilution gas, a plasma-generating gas, or the like. These processing gases are guided from the gas supply unit 55 through the gas flow path 54 to the gas chamber 9 a of the gas shower head 9 and then discharged into the processing chamber A via the gas discharge holes 9 b. An RF (radio frequency) power supply 53 is connected to the gas shower head 9 via a matching box 52. The RF power supply 53 applies, for example, 13.56 MHz radio frequency power to the gas shower head 9. By applying the radio frequency power to the gas shower head 9, a radio frequency electric field is formed between the gas shower head 9 and the mounting table 3, and a capacitively coupled plasma is generated by the gas discharged from the gas shower head 9.

[0030] The processing devices 101 and 102 each include a control device 120. The control device 120 is, for example, a computer, and includes a program storage unit (not shown). The program storage unit stores a program for controlling the substrate processing method in the processing devices 101 and 102. Note that the program may be recorded on a computer-readable storage medium, such as a computer-readable hard disk (HD), flexible disk (FD), compact disk (CD), magnetic optical disk (MO), or memory card, and may be installed into the control device 120 from the storage medium.

[0031] [Processing Apparatus] Next, a configuration example of the processing apparatus 103 that performs plasma processing to modify the flowable film (see step S103 in FIG. 4 described later) will be described with reference to FIG. 3. FIG. 3 is a diagram showing a configuration example of the processing apparatus 103 in the substrate processing system. The processing apparatus 103 has a processing chamber B. In the following description, processing chamber B of the processing apparatus 103 will be referred to as a third processing chamber.

[0032] The processing device 103 executes the process of step S3 in Fig. 2 under the control of the control device 130. That is, a processing gas is supplied into the processing chamber B under reduced pressure, and the substrate W is exposed to the plasma of the processing gas to modify the flowable film 520. The processing device 103 is a microwave plasma processing device that forms surface wave plasma using microwaves and performs anisotropic plasma processing on the substrate W. However, the configuration of the processing device 103 in Fig. 3 is an example and is not limited to this.

[0033] The processing chamber B is a substantially cylindrical container made of a metal material such as aluminum, and is grounded. The processing device 103 has a microwave plasma source 2 for introducing microwaves into the processing chamber B to form surface wave plasma.

[0034] The ceiling wall 10a of the processing chamber B has a metal main body into which are fitted a plurality of dielectric members (hereinafter referred to as dielectric windows 56) of the microwave radiation mechanism 42. This allows the microwave plasma source 2 to introduce microwaves into the processing chamber B through the plurality of dielectric windows 56 in the ceiling wall 10a.

[0035] A susceptor (mounting table) 11 for horizontally supporting a substrate W is provided within the processing chamber B, and is supported by a cylindrical support member 12 that stands via an insulating member 12a at the center of the bottom of the processing chamber B. The susceptor 11 and the support member 12 are made of a material such as a metal such as aluminum whose surface has been anodized (anodized), or an insulating material (ceramics, etc.) having a high-frequency electrode therein.

[0036] Although not shown, the susceptor 11 is also provided with a temperature control mechanism, a gas flow path for supplying a gas for heat transfer to the rear surface of the substrate W, and lifting pins for lifting and lowering to transport the substrate W. Furthermore, an electrostatic chuck for electrostatically attracting the substrate W may be provided.

[0037] Furthermore, an RF power supply 14 is electrically connected to the susceptor 11 via a matching box 13. When RF power is supplied from the RF power supply 14 to the susceptor 11, ions in the plasma are attracted to the substrate W side.

[0038] An exhaust pipe 15 is connected to the side of the bottom of the processing chamber B, and an exhaust device 16 including a vacuum pump is connected to this exhaust pipe 15. By operating this exhaust device 16, the processing chamber B can be evacuated and the pressure inside the processing chamber B can be reduced to a predetermined value. In addition, a side wall 10b of the processing chamber B is provided with a load / unload port 17 for loading and unloading the substrate W, and a gate valve 18 for opening and closing this load / unload port 17.

[0039] The processing apparatus 103 also has a first gas shower unit 21 for discharging a predetermined gas into the processing chamber B from the ceiling wall 10a of the processing chamber B, and a second gas shower unit 22 for introducing a gas from a position between the ceiling wall 10a and the susceptor 11. The processing apparatus 103 further includes a third gas shower unit 23 for introducing a gas from a position between the ceiling wall 10a and the susceptor 11 in the processing chamber B and outside the second gas shower unit 22.

[0040] The first gas shower unit 21 receives an excitation gas (plasma generating gas) such as Ar gas and a process gas that is to be dissociated with high energy from the first gas supply unit 81 via a pipe 83, and discharges these into the process chamber B. The second gas shower unit 22 and the third gas shower unit 23 receive a process gas that is to be prevented from being excessively dissociated from the second gas supply unit 82 via a pipe 84 and a pipe 85, respectively, and discharge these into the process chamber B. However, the process gas may be supplied from any of the first to third gas shower units 21 to 23.

[0041] The microwave plasma source 2 has a microwave output unit 43 that outputs microwaves by distributing them to a plurality of paths, and a microwave transmission unit 40 that transmits the microwaves output from the microwave output unit 43 .

[0042] The microwave output unit 43 includes a microwave power supply, a microwave oscillator, an amplifier, and a distributor. The microwave power supply supplies power to the microwave oscillator. The microwave oscillator generates microwaves at a predetermined frequency (e.g., 860 MHz) using, for example, a PLL. The amplifier amplifies the generated microwaves. The distributor distributes the microwaves amplified by the amplifier while matching the impedance between the input and output sides to minimize microwave loss. Note that, in addition to 860 MHz, various frequencies in the range of 700 MHz to 3 GHz, such as 915 MHz, can be used as the microwave frequency.

[0043] The microwave transmission unit 40 has a plurality of amplifier units 41 and a plurality of microwave radiation mechanisms 42 provided corresponding to the amplifier units 41. For example, seven microwave radiation mechanisms 42 are arranged, one at the center of the top wall 10a and six at equal intervals on a circumference centered on the central one. In this example, the microwave radiation mechanisms 42 are arranged so that the distance between the central microwave radiation mechanism 42 and the outer peripheral microwave radiation mechanisms 42 is equal to the distance between the outer peripheral microwave radiation mechanisms 42.

[0044] The amplifier unit 41 guides the microwaves distributed by the distributor to each microwave radiation mechanism 42. The microwave radiation mechanism 42 has a coaxial tube 51. The coaxial tube 51 has a coaxial microwave transmission line consisting of a cylindrical outer conductor 51a and a rod-shaped inner conductor 51b provided at the center of the outer conductor 51a. The microwave radiation mechanism 42 has a power feeding antenna (not shown) that feeds the microwaves amplified by the amplifier unit 41 to the coaxial tube 51. The microwave radiation mechanism 42 further has a tuner that matches the impedance of the load to the characteristic impedance of the microwave power source, and an antenna unit that radiates the microwaves from the coaxial tube into the processing chamber B.

[0045] The antenna unit is provided at the lower end of the coaxial tube 51 and is fitted into a metal portion of the ceiling wall 10a of the processing chamber B. The antenna unit has a dielectric window 56, and microwaves transmitted through the dielectric window 56 generate surface wave plasma directly below the dielectric window 56 in the processing chamber B.

[0046] The processing device 103 has a control device 130. The control device 130 is, for example, a computer, and has a program storage unit (not shown). The program storage unit stores a program for controlling the substrate processing method in the processing device 103. Note that the program may be recorded on a computer-readable storage medium, such as a computer-readable hard disk (HD), flexible disk (FD), compact disk (CD), magnet optical disk (MO), or memory card, and may be installed into the control device 130 from the storage medium.

[0047] Next, an example of a substrate processing method for forming a silicon oxide film on a substrate W having a concave-convex pattern will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a flowchart showing an example of the substrate processing method. Fig. 5 is a schematic cross-sectional view of the substrate W in each step.

[0048] In step S101, a substrate W having a concave-convex pattern is prepared. Here, the control device 600 of the substrate processing system 1 controls the transfer mechanisms 201, 402, etc. to transfer the substrate W accommodated in the carrier C to the processing device 101 via the atmospheric transfer chamber 400, any one of the load lock chambers 301 to 303, and the vacuum transfer chamber 200, and then places the substrate W on the mounting table 3 of the processing device 101.

[0049] 5A is an example of a schematic cross-sectional view of the substrate W prepared in step S101. A pattern such as a trench or a hole is formed on the surface of the substrate W. As shown in FIG. 5A, a recessed portion 511 and a protruding portion 512 are formed on the substrate W.

[0050] In step S102, a fluid film 520 containing silicon (Si) is formed on the substrate W. Here, the fluid film 520 is formed on the substrate W by PECVD (Plasma Enhanced Chemical Vapor Deposition). Specifically, the control device 120 of the processing device 101 controls the gas supply unit 55 to supply a film formation gas into the processing chamber A (first processing chamber), and controls the RF power supply 53 to apply RF power for plasma generation to the gas shower head 9 to generate plasma, thereby forming the fluid film 520 on the substrate W.

[0051] For example, a first deposition gas containing silicon (Si) (e.g., trisilylamine (TSA) or the like) and a second deposition gas (e.g., ammonia (NH ３) and the like) are supplied to processing chamber A, and plasma is generated in processing chamber A to form a fluid film 520 containing silicon (Si). Polysilazane (PHPS: Perhydro-PolySilazane) can be formed as the fluid film 520. Polysilazane formed by PECVD has fluidity, and can fill the recess 511 with the fluid film 520.

[0052] 5B is an example of a schematic cross-sectional view of the substrate W on which the fluid film 520 is formed in step S102. As shown in FIG. 5B, the fluid film 520 is formed inside the recess 511 and on the upper surfaces of the protrusions 512. That is, the fluid film 520 has a buried portion 520a formed inside the recess 511 and an overburden portion 520b formed on the recess 511 and the protrusions 512. In this way, the fluid film 520 is formed so as to be buried inside the recess 511 and to cover the upper surfaces of the protrusions 512.

[0053] Although the processing apparatus 101 has been described as forming the fluid film 520 on the substrate W by PECVD, the present invention is not limited to this. For example, the fluid film 520 may be formed on the substrate W by coating and forming a film using SOD (Spin On Disk).

[0054] An example of the bond structure of the flowable film 520 formed in step S102 is shown below: The flowable film 520 has at least one of Si—N, Si—H, and Si—NH bonds.

[0055]

[0056] When the formation process of the fluid film 520 is completed, the control device 600 of the substrate processing system 1 controls the transport mechanism 201, etc. to remove the substrate W from the processing device 101, transport it to the processing device 102 via the vacuum transport chamber 200, and place the substrate W on the mounting table 3 of the processing device 102.

[0057] In step S103, a gas containing oxygen (O) is supplied to perform a first modification process on the substrate W. Here, the control device 120 of the processing device 102 controls the gas supply unit 55 to supply a gas containing oxygen (O) into the processing chamber A (second processing chamber) to perform an oxidation process on the flowable film 520, thereby forming a silicon oxide film 530 that is at least partially oxidized.

[0058] The gas containing oxygen (O) is H ２ O, O ２ , O ３ , H ２ O ２ , N ２ A gas containing O, NO, or the like can be used.

[0059] 5C is an example of a schematic cross-sectional view of the substrate W on which a silicon oxide film 530 has been formed in step S103. As shown in FIG. 5C, by supplying a gas containing oxygen (O) to the substrate W, the fluid film 520 is oxidized from the surface of the substrate W to form a silicon oxide film 530. Here, in the silicon oxide film 530, an unoxidized region 531 that has not been oxidized or has been insufficiently oxidized is formed in a deep portion of the buried portion 530a in the recess 511, and an oxidized region 532 that has been oxidized is formed in an upper protrusion 530b and a shallow portion of the buried portion 530a in the recess 511.

[0060] An example of the bond structure in the oxidized region 532 of the silicon oxide film 530 formed in step S103 is shown below. One or more of the Si—N, Si—H, and Si—NH bonds in the flowable film 520 are converted into O—Si—O bonds by a gas containing oxygen (O), thereby forming the silicon oxide film 530. The silicon oxide film 530 formed in the first modification step also contains some Si—N, Si—H, and Si—NH bonds.

[0061]

[0062] When the process of modifying the fluid film 520 to form the silicon oxide film 530 is completed, the process by the control device 600 proceeds to step S104. In step S104, the substrate W is transported to a plasma processing device (processing device 103). The control device 600 of the substrate processing system 1 controls the transport mechanism 201 and the like to unload the substrate W from the processing device 102, transport it to the processing device 103 via the vacuum transfer chamber 200, and place the substrate W on the mounting table 3 of the processing device 103.

[0063] In step S105, the substrate W is exposed to a plasma (first plasma) that does not contain oxygen (O) to subject the substrate W to a second modification process. Here, the control device 130 of the processing device 103 controls the gas supply unit (first gas supply unit 81 and / or second gas supply unit 82) to supply a gas that does not contain oxygen (O) into the processing chamber B (third processing chamber), and controls the microwave output unit 43 to generate plasma in the processing chamber B. The control device 130 may also control the RF power supply 14 to supply bias RF power to the susceptor 11. This draws ions in the plasma toward the substrate W. The bias RF power in step S105 is preferably smaller than the bias RF power in step S106, which will be described later. Alternatively, bias RF power need not be supplied to the susceptor 11.

[0064] Here, the gases not containing oxygen (O) supplied into the processing chamber B include Ar gas, He gas, Ar / He gas (a mixed gas of Ar and He), H ２ / Ar gas (H ２ and Ar mixed gas), H ２ / He gas (H ２ and He mixed gas), H ２ Gas, H ２ / NH ３ Gas (H ２ and N.H. ３ mixed gas), NH ３ The gas is selected from the group consisting of:

[0065] The first plasma not containing oxygen (O) is Ar plasma, He plasma, Ar / He plasma, H ２ / Ar plasma, H ２ / He plasma, H ２ Plasma, H ２ / NH ３ Plasma, NH ３ The method is one selected from the group consisting of plasma, etc.

[0066] In step S106, the substrate W is exposed to a plasma (second plasma) of a gas containing oxygen (O) to subject the substrate W to a third modification process. Here, the control device 130 of the processing device 103 controls the gas supply unit (first gas supply unit 81 and / or second gas supply unit 82) to supply a gas containing oxygen (O) into the processing chamber B (third processing chamber), and controls the microwave output unit 43 to generate plasma in the processing chamber B. The control device 130 may also control the RF power supply 14 to supply bias RF power to the susceptor 11. This draws ions in the plasma toward the substrate W. The bias RF power in step S106 is preferably greater than the bias RF power in step S105. Alternatively, bias RF power need not be supplied to the susceptor 11.

[0067] Here, the gas containing oxygen (O) supplied into the processing chamber B is O ２ / Ar gas (O ２ and Ar mixed gas), O ２ / He gas (O ２ and He mixed gas), O ２ / H ２ / Ar gas (O ２ and H ２ and Ar mixed gas), O ２ / H ２ / He gas (O ２ and H ２ and He mixed gas).

[0068] The second plasma containing oxygen (O) ２ / Ar plasma, O ２ / He plasma, O ２ / H ２ / Ar plasma, O ２ / H ２ / He plasma, etc.

[0069] 5D is an example of a cross-sectional schematic diagram of a substrate W on which a silicon oxide film 540 modified in steps S105 and S106 has been formed. As shown in FIG. 5D, the silicon oxide film 530 is densified by the second and third modification steps to form the silicon oxide film 540. The silicon oxide film 540 has an unoxidized region 541, an oxidized region 542, and a densified oxidized region 543. The unoxidized region 541, like the flowable film 520, has many Si—N, Si—H, and Si—NH bonds. The oxidized region 542, like the silicon oxide film 530, contains both O—Si—O bonds and Si—N, Si—H, and Si—NH bonds. The densified oxidized region 543 has fewer Si—N, Si—H, and Si—NH bonds and many O—Si—O bonds. The second and third modification steps reduce the unoxidized region 541 in the recess 511, and allow the oxidized region 542 and the densified oxidized region 543 to grow in the depth direction.

[0070] An example of the bond structure in the densified oxide region 543 of the silicon oxide film 540 formed in step S106 is shown below: The densified oxide region 543 of the silicon oxide film 540 has many O—Si—O bonds.

[0071]

[0072] In step S107, the second reforming step (S105) and the third reforming step (S106) constitute one cycle, and it is determined whether this cycle has been repeated a predetermined number of times. If this cycle has not been repeated the predetermined number of times (S107, NO), the processing by the control device 130 of the processing device 103 returns to step S105. If this cycle has been repeated the predetermined number of times (S107, YES), the processing by the control device 130 of the processing device 103 proceeds to step S108.

[0073] 5( e) is an example of a schematic cross-sectional view of a substrate W on which a silicon oxide film 550 has been formed after repeated processing. As shown in FIG. 5( e), by repeating the second and third modification steps, the silicon oxide film 540 is further densified to form a silicon oxide film 550. The silicon oxide film 550 has an unoxidized region 551, an oxidized region 552, and a densified oxidized region 553. By repeating the second and third modification steps, the unoxidized region 551 in the recess 511 is further reduced, and the oxidized region 552 and the densified oxidized region 553 progress in the depth direction.

[0074] In step S108, the substrate W is unloaded from the plasma processing apparatus (processing apparatus 103). The control device 600 of the substrate processing system 1 controls the transfer mechanism 201 and the like to unload the substrate W from the processing apparatus 103, and transport it to any one of the carriers C via the vacuum transfer chamber 200, any one of the load lock chambers 301 to 303, or the atmospheric transfer chamber 400, and then accommodates the substrate W in the carrier C.

[0075] In this manner, the silicon oxide film 550 can be embedded in the recess 511 of the substrate W. The embedded portion of the silicon oxide film 550 embedded in the recess 511 of the substrate W is used, for example, as a dielectric material layer of a semiconductor device formed on the substrate W. On the other hand, the upper protrusion of the silicon oxide film 550 is a portion to be removed by CMP (Chemical Mechanical Polishing).

[0076] Next, modification of the silicon oxide film filled in the recess 511 will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic diagram of an oxide film formed on a substrate, and an example of a diagram illustrating the change in wet etching rate (WER) in the depth direction of the silicon oxide film. FIG. 7 is an example of a diagram illustrating the change in wet etching rate (WER) in the depth direction of the silicon oxide film in each process. In the graphs shown in FIGS. 6 and 7, the horizontal axis represents the depth direction (the left side is the surface side, and the right side is the substrate side). The vertical axis represents WER.

[0077] 6 shows the wet etching rate of the silicon oxide film 530 after the first modification step (S103). The more the flowable film 520 is oxidized, the lower the wet etching rate (in other words, the higher the etching resistance). As a result, the silicon oxide film 530 has an unoxidized region 531, which is not oxidized or is insufficiently oxidized, in the deep portion of the buried portion 530a in the recess 511, and an oxidized region 532, which is oxidized, in the upper protrusion 530b and in the shallow portion of the buried portion 530a in the recess 511.

[0078] 7A shows a wet etching rate (first WER) 701 of the silicon oxide film 530 after the first modification step (S103). In the first modification step (S103), the surface side of the substrate W is oxidized by a gas containing oxygen (O). That is, one or more of Si—N, Si—H, and Si—NH in the flowable film 520 are converted to O—Si—O to form the silicon oxide film 530.

[0079] Here, the upper protrusion 530b and the shallow portion of the buried portion 530a in the recess 511 are well oxidized, while the deep portion of the buried portion 530a is not oxidized or is insufficiently oxidized. Therefore, the wet etching rate of the silicon oxide film 530 after the first modification step (S103) is low on the surface side and increases from the surface side toward the substrate side (toward the depth direction of the recess 511).

[0080] 7A shows a wet etching rate 710 (two-dot chain line) when the third modification step (S106) is performed after the first modification step (S103) without performing the second modification step (S105). By performing the third modification step (S106) after the first modification step (S103), the silicon oxide film is densified and the wet etching rate is reduced. However, the formation of a densified oxidized region on the surface side increases the density of activated species of oxygen (O) generated by the second plasma (for example, oxygen radicals (O ＊ ) and the like) from reaching deep portions within the recesses 511. Therefore, as shown by the wet etching rate 710, there is a risk that deep portions within the recesses 511 will not be sufficiently oxidized and densified.

[0081] 7B shows the wet etching rate (second WER) 702 of the silicon oxide film 530 after the second modification step (S105). In the second modification step (S105), the substrate W is exposed to a first plasma that does not contain oxygen (O), thereby breaking at least a part of the O—Si—O bonds in the silicon oxide film 530 on the front surface side of the substrate W. Note that when the oxygen (O)-free gas is mixed with H ２ , N.H. ３ By adding the above, the broken O--Si--O bond forms a bond such as Si--N, Si--H, or Si--NH.

[0082] As a result, in the upper protrusion 530b and the shallow portion of the buried portion 530a in the recess 511, the O-Si-O bonds in the silicon oxide film 530 are broken, thereby increasing the wet etching rate. On the other hand, in the deep portion of the buried portion 530a, the wet etching rate is maintained. As a result, the wet etching rate on the surface side is significantly increased compared to the wet etching rate 701 (dashed line in FIG. 7(b)). On the other hand, the wet etching rate on the substrate side is not increased or is increased only slightly compared to the wet etching rate 701 (dashed line in FIG. 7(b)).

[0083] 7C shows a wet etching rate (third WER) 703 of the silicon oxide film 540 after the third modification step (S106). In the third modification step (S106), the substrate W is exposed to a second plasma containing oxygen (O), thereby recombining broken O—Si—O bonds in the silicon oxide film 540 on the front surface side of the substrate W.

[0084] Here, in the upper protrusion 530b and the shallow portion of the buried portion 530a in the recess 511, the silicon oxide film 530 is made low density by the first plasma that does not contain oxygen (O). Therefore, activated species of oxygen (O) (for example, oxygen radicals (O ＊) etc.) reach deep portions of the buried portion 530a in the recess 511. As a result, the wet etching rate is lower than the wet etching rate 702 (dashed line in FIG. 7C ) not only in the upper ridge 530b and shallow portions of the buried portion 530a in the recess 511 but also in deep portions of the buried portion 530a. Furthermore, the wet etching rate is lower than the wet etching rate 701 (dashed line in FIG. 7C ) not only in the upper ridge 530b and shallow portions of the buried portion 530a in the recess 511 but also in deep portions of the buried portion 530a.

[0085] 7D shows the wet etching rate (fourth WER) 704 of the silicon oxide film 540 after the second modification step (S105) and the third modification step (S106) are repeated multiple times. By repeating the second modification step (S105) and the third modification step (S106) multiple times after the first modification step (S103), the wet etching rate is reduced even in the deep portion of the recess 511. That is, the silicon oxide film 350 can be oxidized and densified even in the deep portion of the recess 511.

[0086] As described above, according to the substrate processing method, the silicon oxide film 550 can be embedded in the recess 511 of the substrate W. Furthermore, the silicon oxide film 550 can be oxidized to a deep portion within the recess 511. That is, the wet etching rate of the silicon oxide film 550 can be reduced to a deep portion within the recess 511. In other words, the silicon oxide film 550 can be densified to a deep portion within the recess 511.

[0087] One possible method for filling the recesses 511 with a silicon oxide film is to form a silicon oxide film in the recesses 511 from the bottom up by repeating multiple times the steps of forming a fluid film in part of the recesses 511 and modifying the fluid film by exposing it to plasma containing oxygen (O) to form a silicon oxide film. However, with this method, the upper surfaces of the protrusions 512 are directly exposed to the plasma. Therefore, there is a risk that the upper surfaces of the protrusions 512 may be damaged by the plasma.

[0088] 4, the fluid film 520 is formed up to the upper protrusion 520b, and the upper surface of the convex portion 512 is covered with the fluid film 520. This makes it possible to reduce damage to the upper surface of the convex portion 512 caused by plasma.

[0089] It should be noted that the film quality of the upper protrusion of the silicon oxide film 550 may be degraded due to repeated bonding and breaking of O—Si—O bonds. However, as described above, the upper protrusion is a portion that is removed by CMP or the like, and therefore there is little risk of the upper protrusion deteriorating the characteristics of the dielectric material layer of the semiconductor device formed on the substrate W.

[0090] The substrate processing method has been described above, but the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims.

[0091] 1 Substrate processing system 101 to 104 Processing device 120, 130, 600 Control device 200 Vacuum transfer chamber 301 to 303 Load lock chamber 400 Atmospheric transfer chamber 511 Concave portion 512 Convex portion 520 Flowable film 520a Buried portion 520b Upper protrusion 530 Silicon oxide film 530a Buried portion 530b Upper protrusion 531 Unoxidized region 532 Oxidized region 540 Silicon oxide film 541 Unoxidized region 542 Oxidized region 543 Densified oxide region 550 Silicon oxide film 551 Unoxidized region 552 Oxidized region 553 Densified oxide region W substrate

Claims

1. A method for forming a silicon oxide film, comprising: a step of preparing a substrate having a concave-convex pattern; a step of forming a fluid film containing silicon in concave portions and on the upper surfaces of convex portions of the substrate; a first modification step of supplying an oxygen-containing gas to the substrate and modifying the fluid film to form a silicon oxide film; a second modification step of exposing the substrate to a first plasma that does not contain oxygen to modify the silicon oxide film; and a third modification step of exposing the substrate to a second plasma that contains oxygen to modify the silicon oxide film.

2. The substrate processing method according to claim 1, wherein after the first modification step, the second modification step and the third modification step constitute one cycle, and this cycle is repeated.

3. The first plasma in the second modification step may be Ar plasma, He plasma, Ar / He plasma, or H ２ / Ar plasma, H ２ / He plasma, H ２ Plasma, H ２ / NH ３ Plasma, NH ３ 3. The substrate processing method according to claim 1, wherein the method is one selected from the group consisting of a gas, a plasma, and a gas.

4. The second plasma in the third modification step is O ２ / Ar plasma, O ２ / He plasma, O ２ / H ２ / Ar plasma, O ２ / H ２ 4. The substrate processing method according to claim 3, wherein the plasma is one selected from the group consisting of a fluorine-containing gas (HF) plasma, a fluorine-containing gas (H2O ... and a He plasma.

5. The oxygen-containing gas in the first reforming step is H ２ O, O ２ , O ３ , H ２ O ２ , N ２ The substrate processing method according to claim 4 , wherein the gas contains either O or NO.

6. The substrate processing method according to claim 1, wherein the first modifying step modifies the flowable film into the silicon oxide film having a first wet etching rate.

7. The substrate processing method according to claim 6, wherein the second modification step modifies the silicon oxide film to have a second wet etching rate higher than the first wet etching rate.

8. The substrate processing method according to claim 7, wherein the third modification step modifies the silicon oxide film to have a third wet etching rate lower than the second wet etching rate.

9. The substrate processing method according to claim 1, wherein the step of forming the fluid film forms the fluid film having at least one of Si-N, Si-H, and Si-NH bonds.

10. The substrate processing method according to claim 9, wherein the first modification step converts one or more of Si—N, Si—H, and Si—NH bonds in the flowable film into O—Si—O bonds to form the silicon oxide film.

11. The substrate processing method according to claim 10, wherein the second modifying step cuts at least a part of the O—Si—O bonds of the silicon oxide film.

12. The substrate processing method according to claim 11, wherein the third modifying step recombines broken O-Si-O bonds in the silicon oxide film.

13. The substrate processing method according to claim 1, wherein the first plasma and the second plasma are microwave plasmas.

14. The substrate processing method according to claim 1, wherein the fluid film is a polysilazane film.

15. The substrate processing method according to claim 1, wherein the flowable film is formed by PECVD or coating film formation.

16. A substrate processing system comprising: a first substrate processing apparatus that forms a fluid film containing silicon in recesses and on the top surfaces of protrusions of a substrate having a concave-convex pattern; a second substrate processing apparatus that supplies an oxygen-containing gas to the substrate and modifies the fluid film to form a silicon oxide film; a third substrate processing apparatus that exposes the substrate to a first plasma that does not contain oxygen and / or a second plasma that contains oxygen to modify the silicon oxide film; and a transfer apparatus that transfers substrates to the first substrate processing apparatus, the second substrate processing apparatus, and the third substrate processing apparatus.

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