Substrate treatment method, hard mask forming method, and substrate treatment system

Abstract

The present invention provides a substrate treatment method for forming a carbon-containing film, a method for forming a hard mask, and a substrate treatment system.　The substrate treatment method includes a step for forming a first laminate in which first insulating films and second insulating films are alternately laminated on a substrate, and a step for forming a carbon-containing film on the first laminate, wherein the direction of stress of the first laminate and the direction of stress of the carbon-containing film are different, and the absolute value of the difference between the absolute value of the strength of the stress of the first laminate and the absolute value of the strength of the stress of the carbon-containing film is equal to or less than 100 MPa.

Description

SUBSTRATE PROCESSING METHOD, HARD MASK FORMING METHOD, AND SUBSTRATE PROCESSING SYSTEM

[0001] The present disclosure relates to a substrate processing method, a method for forming a hard mask, and a substrate processing system.

[0002] Patent Document 1 discloses that a diamond-like carbon layer is formed on a film stack in which a first layer and a second layer are laminated.

[0003] Special Publication No. 2022-505395

[0004] In one aspect, the present disclosure provides a substrate processing method for forming a carbon-containing film, a method for forming a hard mask, and a substrate processing system.

[0005] In order to solve the above-described problems, according to one aspect, there is provided a substrate processing method including the steps of forming a first stack of alternately stacked first insulating films and second insulating films on a substrate, and forming a carbon-containing film on the first stack of films, wherein the direction of stress in the first stack of films is different from the direction of stress in the carbon-containing film, and the absolute value of the difference between the absolute value of the stress intensity of the first stack of films and the absolute value of the stress intensity of the carbon-containing film is 100 MPa or less.

[0006] According to one aspect, a substrate processing method for forming a carbon-containing film, a hard mask forming method, and a substrate processing system can be provided.

[0007] 1 is a flowchart illustrating a substrate processing method according to an embodiment of the present invention; FIG. 2 is a schematic cross-sectional view illustrating a structure of a film formed on a substrate; FIG. 3 is a diagram illustrating an example of a processing system according to an embodiment of the present invention; and FIG.

[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] For example, a patterning technique using a carbon hard mask is known as a technique for patterning an underlayer. For example, a carbon hard mask is formed on an underlayer (e.g., a stack of a silicon oxide film and a silicon nitride film). When considering the lithography process, the underlayer needs to be a neutral film with almost no film stress. Similarly, the carbon hard mask needs to be a neutral film with almost no film stress. Because neutral carbon hard masks have low film density, they need to be thickened for patterning, which may cause problems with etching characteristics. For future miniaturization technology, a technique for forming a thin carbon hard mask with good etching characteristics is expected.

[0010] [Substrate Processing Method] A substrate processing method according to this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is an example of a flowchart illustrating the substrate processing method according to this embodiment. FIG. 2 is an example of a cross-sectional schematic diagram showing the structure of a film formed on a substrate. Here, as shown in FIG. 2, a first stacked body 210 in which first insulating films 211 and second insulating films 212 are alternately stacked is formed on the substrate, and a carbon-containing film 220 is formed on the first stacked body 210. The carbon-containing film 220 is used, for example, as a carbon hard mask when etching the first stacked body 210.

[0011] In step S101, a first insulating film 211 is formed on a substrate. The first insulating film 211 is, for example, a silicon nitride (SiN) film. The first insulating film 211 is a film having tensile stress.

[0012] In step S102, a second insulating film 212 is formed on the substrate. The second insulating film 212 is, for example, a silicon oxide film (SiO ２ ) The second insulating film 212 is a film having compressive stress.

[0013] In step S103, it is determined whether the formation of the first insulating film 211 and the second insulating film 212 has been repeated a predetermined number of times. If the formation has not been repeated the predetermined number of times (S103: NO), the process returns to step S101, and the formation of the first insulating film 211 and the second insulating film 212 is repeated. If the formation has been repeated the predetermined number of times (S103: YES), the process proceeds to step S104.

[0014] The processes of steps S101 to S103 form a first stack 210 in which first insulating films 211 and second insulating films 212 are alternately stacked on the substrate. Here, the first stack 210 is formed as a stack having tensile stress as a whole. Specifically, the first stack 210 has a strong stress of 1 GPa or more (the absolute value of the stress intensity is 1 GPa or more). Note that the direction of tensile stress is defined as positive, and the direction of compressive stress is defined as negative.

[0015] Specifically, the first insulating film 211 is a film having a strong tensile stress, and the second insulating film 212 is a film having a weak compressive stress. That is, the first insulating film 211 and the second insulating film 212 have stresses in opposite directions, and the absolute value of the stress intensity of the first insulating film 211 is greater than the absolute value of the stress intensity of the second insulating film 212. As a result, the first stacked body 210 has a strong tensile stress with an absolute value of the stress intensity of 1 GPa or more.

[0016] Furthermore, the strength of the stress in the first stack 210 is controlled by controlling the ratio between the thickness of the first insulating film 211 and the thickness of the second insulating film 212. For example, by increasing the ratio of the first insulating film 211 having tensile stress, the strength of the stress in the first insulating film 211 having tensile stress as a whole is increased. Furthermore, by increasing the ratio of the second insulating film 212 having compressive stress, the strength of the stress in the first insulating film 211 having tensile stress as a whole is decreased.

[0017] The above-described relationship between the direction and strength of the stress of the first insulating film 211 and the second insulating film 212 is merely an example and is not limited to this. The first stack 210 may be formed as a stack having a tensile stress whose absolute value of stress strength is 1 GPa or more as a whole.

[0018] Furthermore, the uppermost layer of the first stacked body 210 formed by the processes of steps S101 to S103 is the second insulating film 212 (silicon oxide film), but is not limited to this. For example, the uppermost layer may be the first insulator (silicon nitride film).

[0019] In step S104, the surface of the first stack 210 formed on the substrate is modified to form a modified layer 212a. Here, a modifying agent is supplied to the substrate, and a hydrophobic treatment is performed on the surface of the first stack 210. That is, the hydrophobic treatment is performed on the surface of the second insulating film 212 (silicon oxide film) formed on the top layer of the first stack 210. Note that the top layer may be the first insulating film (silicon nitride film), and in that case, the hydrophobic treatment is also performed in the same way.

[0020] Here, the surface of the first stack 210 formed by the processes of steps S101 to S103 is a second insulating film 212 (silicon oxide film), and is made of hydrophilic SiO ２ In the modification process of step S104, a modifying agent is supplied to the substrate, and the modifying agent is physically adsorbed and / or chemically bonded to, or chemically reacted with, the OH groups on the surface of the first stack 210. This makes the surface of the first stack 210 hydrophobic. In the modification process, a gasified modifying agent (modifying gas) may be supplied to the substrate. Examples of the modifying gas include DCS (dichlorosilane), SiH ４ (Silane), Si ２ H ６ (disilane), Si ３ H ８Any of trisilane, trichlorosilane, higher order silane, organic Si precursor, etc. can be used. Furthermore, in the modification process, a liquid modifier (modifying liquid) can be supplied to the substrate. Examples of the modifier liquid that can be used include HMDS (hexamethyldisilazane), TMSDMA (trimethylsilyldimethylamine), and SAM (self-assemble monolayer) agents.

[0021] In step S105, a carbon-containing film 220 is formed on the substrate. Here, the substrate is exposed to plasma of a process gas containing a carbon-containing gas, and the carbon-containing film 220 is formed on the hydrophobicized substrate surface. Here, the carbon-containing film 220 is, for example, a diamond-like carbon (DLC) film. Note that, compared to, for example, a polymer-like carbon (PLC) film, the DLC film has a higher density, higher dry etching resistance, and stronger stress.

[0022] The carbon-containing film 220 (DLC film) is a film having a strong compressive stress. Specifically, the carbon-containing film 220 has a strong stress of -1 GPa or more (the absolute value of the stress intensity is 1 GPa or more). Note that the direction of the stress is defined as positive in the case of tensile stress, and negative in the case of compressive stress. The carbon-containing film 220 (DLC film) is also resistant to dry etching.

[0023] 1 , the carbon-containing film 220 can be formed on the first stack 210. Here, when the carbon-containing film 220 is used as a carbon hard mask when etching the first stack 210, a carbon-containing film 220 (DLC film) with high density and high etching resistance can be used. Therefore, the thickness of the carbon hard mask can be made thinner than when, for example, a low-density PLC film is used as the carbon hard mask. This reduces the processing time required to form the carbon hard mask and improves the throughput of the substrate processing apparatus.

[0024] Furthermore, compared to the case where a metal-containing hard mask having high etching resistance is used, the carbon-containing film 220 (DLC film) can prevent metal derived from the hard mask from remaining as impurities in holes after etching of the substrate and affecting subsequent substrate processing.

[0025] Furthermore, the carbon-containing film 220 (DLC film) has high etching resistance and exhibits strong compressive stress. Therefore, the stress of the carbon-containing film 220 may cause the substrate to warp. In contrast, according to the substrate processing method shown in FIG. 1 , the direction of the stress of the first stack 210 differs from the direction of the stress of the carbon-containing film 220. Specifically, by stacking the first stack 210, which has tensile stress, and the carbon-containing film 220, which has compressive stress, the stresses cancel each other out, thereby reducing the overall stress of the substrate. This reduces warpage of the substrate. For example, when a hard mask is formed for mask etching the carbon-containing film 220 and a pattern is formed on a resist film by a lithography process, reducing warpage of the substrate allows for the formation of a well-shaped pattern.

[0026] The difference in the strength of the stress in the first stacked body 210 and the strength of the stress in the carbon-containing film 220, in other words, the difference between the absolute value of the stress in the first stacked body 210 and the absolute value of the stress in the carbon-containing film 220, is preferably within a range of ±100 MPa (the absolute value of the difference is 100 MPa or less), which further reduces the stress in the entire substrate and reduces warpage of the substrate.

[0027] Furthermore, the absolute value of the stress intensity of the carbon-containing film 220 is controlled based on the absolute value of the stress intensity of the first stacked body 210 so that the difference is within a range of ±100 MPa (the absolute value of the difference is 100 MPa or less). Here, by increasing the film thickness of the carbon-containing film 220, the stress intensity of the carbon-containing film 220 increases, and by decreasing the film thickness of the carbon-containing film 220, the stress intensity of the carbon-containing film 220 decreases. That is, the film thickness of the carbon-containing film 220 is controlled based on the stress intensity of the first stacked body 210. This allows the difference between the absolute value of the stress intensity of the first stacked body 210 and the absolute value of the stress intensity of the carbon-containing film 220 to be within a range of ±100 MPa (the absolute value of the difference is 100 MPa or less).

[0028] Furthermore, by subjecting the surface of the first stack 210 to a modification treatment (hydrophobization treatment) (S104) and forming a carbon-containing film 220 on the hydrophobized substrate surface (S105), the adhesion between the first stack 210 and the carbon-containing film 220 is improved, and peeling of the carbon-containing film 220 is suppressed.

[0029] Although the carbon-containing film 220 has been described as being formed in a single layer, the present invention is not limited to this, and a second stack may be formed by stacking a plurality of carbon-containing films 220. This allows the carbon hard mask to have a large thickness.

[0030] Furthermore, when forming a second stacked body by stacking a plurality of carbon-containing films 220 on the first stacked body 210, after forming a carbon-containing film 220, a modification process for modifying the surface of the carbon-containing film 220 may be added before forming the next carbon-containing film 220. In the modification process, similar to step S104, the surface of the carbon-containing film 220 is made hydrophobic. This improves the adhesion between the carbon-containing films 220, and makes it possible to suppress peeling of the carbon-containing film 220.

[0031] Although the carbon-containing film 220 has been described as a film having a strong compressive stress of +1 GPa or more, the present invention is not limited to this. The carbon-containing film 220 may also be a film having a strong tensile stress of +1 GPa or more. In this case, the first stacked body 210 may be a film having a strong compressive stress of -1 GPa or more (the absolute value of the stress intensity is 1 GPa or more). Furthermore, the difference between the absolute value of the stress intensity of the first stacked body 210 and the absolute value of the stress intensity of the carbon-containing film 220 may be ±100 MPa or less.

[0032] [Processing System] Next, an example of a processing system (substrate processing system) PS for performing the substrate processing shown in Fig. 1 will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of the processing system PS according to this embodiment.

[0033] The processing system PS includes processing devices PM1 to PM4, a vacuum transfer chamber VTM, load lock chambers LL1 to LL3, an atmospheric transfer chamber LM, load ports LP1 to LP3, and a general control unit CU.

[0034] The processing devices PM1 to PM4 are connected to the vacuum transfer chamber VTM via gate valves G11 to G14, respectively. The interior of each of the processing devices PM1 to PM4 is depressurized to a predetermined vacuum atmosphere. Each of the processing devices PM1 to PM4 performs a desired process on the substrate W therein. The processing device PM1 is a device that performs a first process (a process for forming the first stack 210 shown in steps S101 to S103). The processing device PM2 is a device that performs a second process (a modification process (hydrophobization process) shown in step S104). The processing device PM3 is a device that performs a third process (a process for forming the carbon-containing film 220 shown in step S105). The processing device PM4 is a device that performs the same process as any of the processing devices PM1 to PM3 or a different process.

[0035] The interior of the vacuum transfer chamber VTM is depressurized to a predetermined vacuum atmosphere. A transport mechanism TR1 is provided inside the vacuum transfer chamber VTM. The transport mechanism TR1 is configured to be able to transport substrates W under a reduced pressure. The transport mechanism TR1 transports substrates W to and from processing devices PM1 to PM4 and load lock chambers LL1 to LL3. The transport mechanism TR1 has, for example, two forks FK11 and FK12 that can move independently. Each of the forks FK11 and FK12 is configured to be able to hold a substrate W.

[0036] The load lock chambers LL1 to LL3 are connected to the vacuum transfer chamber VTM via gate valves G21 to G23, respectively. The load lock chambers LL1 to LL3 are connected to the atmospheric transfer chamber LM via gate valves G31 to G33, respectively. The interior of the load lock chambers LL1 to LL3 can be switched between atmospheric and vacuum atmospheres.

[0037] The atmospheric transfer chamber LM has an atmospheric atmosphere inside. For example, a downflow of clean air is formed inside the atmospheric transfer chamber LM. An aligner AN is provided inside the atmospheric transfer chamber LM. The aligner AN aligns the substrate W. A transport mechanism TR2 is provided in the atmospheric transfer chamber LM. The transport mechanism TR2 transports substrates W to the load lock chambers LL1 to LL3, the carriers C in the load ports LP1 to LP3, and the aligner AN.

[0038] The load ports LP1 to LP3 are provided on the long side walls of the atmospheric transfer chamber LM. A carrier C is attached to each of the load ports LP1 to LP3. The carrier C is, for example, a front opening unified pod (FOUP).

[0039] The overall control unit CU is, for example, a computer. The overall control unit CU includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and an auxiliary storage device. The CPU operates based on programs stored in the ROM or the auxiliary storage device, and controls each component of the processing system PS. For example, the overall control unit CU executes the operation of processing devices PM1 to PM4, the operation of transport mechanisms TR1 and TR2, the opening and closing of gate valves G11 to G14, G21 to G23, and G31 to G33, and the switching of the atmosphere in load lock chambers LL1 to LL3.

[0040] [Operation of Processing System] An example of the operation of the processing system PS according to this embodiment will be described with reference to Figure 3. The following description will be given taking as an example a case where the processing system PS performs substrate processing (see Figure 1). The operation of the processing system PS according to this embodiment is performed under the control of the overall control unit CU.

[0041] First, the carrier C containing a plurality of substrates W is attached to the load port LP1.

[0042] Next, the transport mechanism TR2 transports the substrate W accommodated in the carrier C to the aligner AN. Next, the aligner AN aligns the substrate W. Next, the overall control unit CU switches the gate valve G31 from a closed state to an open state. Next, the transport mechanism TR2 receives the substrate W from the aligner AN and transports it to the load lock chamber LL1, which is in an atmospheric atmosphere. Next, the overall control unit CU switches the gate valve G31 from an open state to a closed state. Next, the overall control unit CU switches the atmosphere in the load lock chamber LL1 from an atmospheric atmosphere to a vacuum atmosphere.

[0043] Next, the overall control unit CU switches the closed gate valves G11 and G21 to an open state. Next, the transport mechanism TR1 receives the substrate W from the load lock chamber LL1 and transports it to the processing device PM1. Next, the overall control unit CU switches the open gate valves G11 and G21 to a closed state.

[0044] Next, the processing device PM1 performs the first process (the process of forming the first stack 210 shown in steps S101 to S103).

[0045] Next, the overall control unit CU switches the closed gate valves G11 and G12 to an open state. Next, the transport mechanism TR1 receives the substrate W from the processing device PM1 and transports it to the processing device PM2. Next, the overall control unit CU switches the open gate valves G11 and G12 to a closed state.

[0046] Next, the treatment device PM2 performs the second treatment (the modification treatment (hydrophobization treatment) shown in step S104).

[0047] Next, the overall control unit CU switches the closed gate valves G12 and G13 to an open state. Next, the transport mechanism TR1 receives the substrate W from the processing device PM2 and transports it to the processing device PM3. Next, the overall control unit CU switches the open gate valves G12 and G13 to a closed state.

[0048] Next, the processing apparatus PM3 performs a third process (a process of forming the carbon-containing film 220 shown in step S105).

[0049] Next, the overall control unit CU switches the gate valves G13 and G23, which were closed, to an open state. Next, the transport mechanism TR1 receives the substrate from the processing device PM4 and transports it to the load lock chamber LL3, which has a vacuum atmosphere. Next, the overall control unit CU switches the gate valves G13 and G23, which were open, to a closed state. Next, the overall control unit CU switches the atmosphere inside the load lock chamber LL3 from a vacuum atmosphere to an air atmosphere.

[0050] Next, the overall control unit CU switches the gate valve G33, which is closed, to an open state. Next, the transport mechanism TR2 receives the substrate W from the load lock chamber LL3, transports it to the carrier C attached to the load port LP3, and stores the substrate W in the carrier C. This completes the processing of one substrate W.

[0051] In the operation of the processing system PS described above, the substrate W is transferred from the atmospheric transfer chamber LM to the vacuum transfer chamber VTM via the load lock chamber LL1, and from the vacuum transfer chamber VTM to the atmospheric transfer chamber LM via the load lock chamber LL3. However, the transfer route of the substrate W is not limited to this. The substrate W may be transferred from the atmospheric transfer chamber LM to the vacuum transfer chamber VTM via any of the load lock chambers LL1 to LL3. The substrate W may be transferred from the vacuum transfer chamber VTM to the atmospheric transfer chamber LM via any of the load lock chambers LL1 to LL3.

[0052] Although the first process (S101 to S103), the second process (S104), and the third process (S105) have been described as being performed by separate processing devices PM1 to PM3, this is not limited to this, and any of the processes may be performed by the same processing device, or all of the processes may be performed by one processing device.

[0053] [Processing Device 1] Next, an example of processing devices PM1 to PM4 will be described using processing device 1 shown in Fig. 4. Fig. 4 is a diagram showing an example of processing device 1. Note that processing devices PM2 to PM4 may also have a similar configuration.

[0054] The processing apparatus 1 includes a substantially cylindrical airtight processing vessel 2. An exhaust chamber 21 is provided in the center of the bottom wall of the processing vessel 2.

[0055] The exhaust chamber 21 has, for example, a substantially cylindrical shape that protrudes downward. An exhaust flow path 22 is connected to the exhaust chamber 21, for example, at a side surface of the exhaust chamber 21.

[0056] An exhaust unit 24 is connected to the exhaust flow path 22 via a pressure adjustment unit 23. The pressure adjustment unit 23 includes a pressure adjustment valve such as a butterfly valve. The exhaust flow path 22 is configured so that the pressure inside the processing vessel 2 can be reduced by the exhaust unit 24. A transfer port 25 is provided on the side of the processing vessel 2. The transfer port 25 is configured to be freely opened and closed by a gate valve 26. The substrate W is loaded and unloaded between the processing vessel 2 and a transfer chamber (not shown) via the transfer port 25.

[0057] A mounting table 3 for holding a substrate W substantially horizontally is provided within the processing chamber 2. The mounting table 3 is substantially circular in plan view and supported by a support member 31. A substantially circular recess 32 for mounting a substrate W having a diameter of, for example, 300 mm is formed in the surface of the mounting table 3. The recess 32 has an inner diameter slightly larger (for example, about 1 mm to 4 mm) than the diameter of the substrate W. The depth of the recess 32 is configured to be substantially the same as the thickness of the substrate W. The mounting table 3 is made of a ceramic material such as aluminum nitride (AlN). Alternatively, the mounting table 3 may be made of a metal material such as nickel (Ni). Note that instead of the recess 32, a guide ring for guiding the substrate W may be provided around the periphery of the surface of the mounting table 3.

[0058] A grounded lower electrode 33, for example, is embedded in the mounting table 3. A temperature adjustment mechanism 34 is embedded below the lower electrode 33. The temperature adjustment mechanism 34 adjusts the temperature of the substrate W placed on the mounting table 3 to a set temperature based on a control signal from the control unit 9. If the mounting table 3 is made entirely of metal, the entire mounting table 3 functions as the lower electrode, so the lower electrode 33 does not need to be embedded in the mounting table 3. The mounting table 3 is provided with a plurality of (for example, three) lifting pins 41 for holding and lifting the substrate W placed on the mounting table 3. The lifting pins 41 are made of a material such as alumina (Al ２ O ３ The lift pins 41 may be made of ceramics such as quartz or the like. The lower ends of the lift pins 41 are attached to a support plate 42. The support plate 42 is connected to a lift mechanism 44 provided outside the processing vessel 2 via a lift shaft 43.

[0059] The lifting mechanism 44 is installed, for example, at the bottom of the exhaust chamber 21. The bellows 45 is provided between the lifting mechanism 44 and an opening 21a for the lifting shaft 43 formed in the bottom surface of the exhaust chamber 21. The support plate 42 may be shaped so that it can be raised and lowered without interfering with the support member 31 of the mounting table 3. The lifting pins 41 are configured to be able to be raised and lowered between an upper side and a lower side of the surface of the mounting table 3 by the lifting mechanism 44. In other words, the lifting pins 41 are configured to be able to protrude from the top surface of the mounting table 3.

[0060] A gas supply unit 5 is provided on the ceiling wall 27 of the processing vessel 2 via an insulating member 28. The gas supply unit 5 forms an upper electrode and faces the lower electrode 33. An RF power supply 51 is connected to the gas supply unit 5 via a matching box 511. The frequency of the RF power supply 51 is, for example, 13 MHz to 2.45 GHz. By supplying RF power from the RF power supply 51 to the upper electrode (gas supply unit 5), an RF electric field is generated between the upper electrode (gas supply unit 5) and the lower electrode 33. The gas supply unit 5 includes a hollow gas diffusion chamber 52. A number of holes 53 are arranged, for example, evenly, on the bottom surface of the gas diffusion chamber 52 for dispersing and supplying the processing gas into the processing vessel 2. A heating mechanism 54 is embedded in the gas supply unit 5, for example, above the gas diffusion chamber 52. The heating mechanism 54 is heated to a set temperature by receiving power from a power supply unit (not shown) based on a control signal from the control unit 9.

[0061] A gas supply path 6 is provided in the gas diffusion chamber 52. The gas supply path 6 is connected to the gas diffusion chamber 52. A gas source 61 is connected to the upstream side of the gas supply path 6 via a gas line 62. The gas source 61 includes, for example, supply sources of various process gases, mass flow controllers, and valves (none of which are shown). The various process gases include the above-mentioned raw material gases and modifying gases. The various process gases are introduced from the gas source 61 into the gas diffusion chamber 52 via the gas line 62.

[0062] The processing device 1 includes a control unit 9. The control unit 9 is, for example, a computer, and includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), an auxiliary storage device, etc. The CPU operates based on a program stored in the ROM or the auxiliary storage device, and controls the operation of the processing device 1. The control unit 9 may be provided inside the processing device 1 or may be provided externally. If the control unit 9 is provided externally to the processing device 1, the control unit 9 can control the processing device 1 via communication means such as wired or wireless.

[0063] 4 has been described as a parallel plate type single wafer processing apparatus, but is not limited to this. It may also be a plasma processing apparatus using microwaves or a plasma processing apparatus using VHF, and is not limited to these.

[0064] Furthermore, the processing apparatus 1 (processing apparatuses PM1 to PM4) may be configured to include a first RF power supply that applies a first high frequency power to the upper electrode (gas supply unit 5) and / or the lower electrode 33 to generate plasma, and a second RF power supply that applies a second high frequency power to the upper electrode (gas supply unit 5) and / or the lower electrode 33 to attract ions in the plasma to the substrate.

[0065] Furthermore, the processing apparatus 1 (processing apparatuses PM1 to PM4) has been described as a plasma processing apparatus including an upper electrode (gas supply unit 5), a lower electrode 33, and an RF power supply 51, but is not limited to this. The processing apparatus may be a processing apparatus that omits the upper electrode, the lower electrode 33, and the RF power supply 51 and processes the substrate W with a processing gas without generating plasma.

[0066] Next, a case where the first insulating film 211 (silicon nitride film) is formed on the substrate W using the processing apparatus PM1 (processing apparatus 1) will be described.

[0067] Here, a first silicon-containing gas containing silicon (Si) and a nitriding gas containing nitrogen (N) are supplied into the processing chamber 2 to form a first insulating film 211 (silicon nitride film) on the substrate W.

[0068] Furthermore, by using VHF or MW waves as high-frequency power for generating plasma and using PECVD (Plasma-Enhanced Chemical Vapor Deposition) with low ion energy incident on the substrate or thermal CVD with high-temperature film formation, it is possible to form the first insulating film 211 with strong tensile stress.

[0069] Furthermore, in the processing apparatus 1 that uses the VHF band as high-frequency power for generating plasma, the first insulating film 211 having a strong tensile stress can be formed by increasing the gap distance between the upper electrode and the lower electrode and increasing the pressure inside the processing vessel.

[0070] For example, when plasma is generated using high frequency power in the VHF band and the first insulating film 211 is formed by PECVD, the first insulating film 211 can be formed with a strong tensile stress of 0.6 GPa to 1.3 GPa by setting the gap distance between the upper electrode and the lower electrode to 60 mm to 130 mm and the pressure inside the processing chamber to 400 mTorr to 1000 mTorr.

[0071] Next, a case where the second insulating film 212 (silicon oxide film) is formed on the substrate W using the processing apparatus PM1 (processing apparatus 1) will be described.

[0072] Here, a second silicon-containing gas containing silicon (Si) and an oxidizing gas containing oxygen (O) are supplied into the processing chamber 2 to form a second insulating film 212 (silicon oxide film) on the substrate W.

[0073] Next, a process for modifying the surface of the first stack 210 using the processing device PM2 (processing device 1) will be described.

[0074] Here, a modifying gas is supplied into the processing chamber 2 to modify the surface of the first stack 210 formed on the substrate W. Specifically, DCS (dichlorosilane) gas, an example of a modifying gas, is supplied into the processing chamber 2 for a predetermined time, for example, 2 to 30 seconds, and the substrate W is exposed to the supplied DCS gas. The substrate temperature is set to a temperature range of 400°C to 700°C. This makes the top surface of the first stack 210 hydrophobic, thereby improving adhesion to the carbon-containing film 220.

[0075] Next, a case where the carbon-containing film 220 is formed using the processing apparatus PM3 (processing apparatus 1) will be described.

[0076] Here, a carbon-containing gas is supplied into the processing chamber 2 to form a carbon-containing film 220 on the substrate W.

[0077] The carbon-containing gas may be a gas containing carbon (C) and hydrogen (H) (CxHy), a gas containing carbon (C) and fluorine (F) (CxFy), or a gas containing carbon (C) and oxygen (O) (for example, CO ２ ) and a gas containing carbon (C) and a metal (e.g., an organometallic precursor such as TDMAT) (note that x and y are arbitrary numbers). The carbon-containing gas may be, for example, CH ４ , C ２ H ２ , C ２ H ４ , C ３ H ６ , C ６ H ６ The process gas may also contain an inert gas or a dilution gas (e.g., H ２ , Ar, He, O ２ , N ２ ) may also be included.

[0078] Here, examples of film formation conditions for forming the carbon-containing film 220 having a stress of 1 GPa or more are given below: Processing pressure: 5 mT to 200 mT Plasma power: 10 W to 300 W Carbon-containing film thickness: 500 nm to 2 μm

[0079] Furthermore, by using PECVD in which the ions incident on the substrate have high energy, the carbon-containing film 220 having a strong compressive stress can be formed.

[0080] In addition, in the processing apparatus 1 that uses VHF band power as plasma-generating radio frequency power, shortening the gap distance between the upper electrode and the lower electrode makes it possible to form the carbon-containing film 220 having a strong compressive stress. Alternatively, applying VHF band radio frequency power for generating plasma to the upper electrode and supplying RF power for attracting ions to the lower electrode also makes it possible to form the carbon-containing film 220 having a strong compressive stress.

[0081] 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.

[0082] 210 First laminate 211 First insulating film 212 Second insulating film 212a Modified layer 220 Carbon-containing film

Claims

1. A substrate processing method comprising the steps of: forming a first stack of alternating first insulating films and second insulating films on a substrate; and forming a carbon-containing film on the first stack; wherein the direction of stress in the first stack is different from the direction of stress in the carbon-containing film; and the absolute value of the difference between the absolute value of the stress intensity of the first stack and the absolute value of the stress intensity of the carbon-containing film is 100 MPa or less.

2. The substrate processing method according to claim 1, wherein the direction of stress in the first stack is tensile stress, and the direction of stress in the carbon-containing film is compressive stress.

3. The substrate processing method according to claim 1, wherein the absolute value of the stress intensity of the first stack is 1 GPa or more, and the absolute value of the stress intensity of the carbon-containing film is 1 GPa or more.

4. The substrate processing method according to claim 1, wherein the first insulating film is a silicon nitride film, and the second insulating film is a silicon oxide film.

5. The substrate processing method according to claim 4, wherein the uppermost layer of the first stack is the second insulating film.

6. The substrate processing method according to claim 5, wherein the direction of the stress in the first insulating film is tensile stress, the direction of the stress in the second insulating film is compressive stress, and the absolute value of the strength of the stress in the first insulating film is greater than the absolute value of the strength of the stress in the second insulating film.

7. The substrate processing method according to claim 6, wherein the strength of the stress of the first laminate is controlled by the ratio between the film thickness of the first laminate and the film thickness of the second insulating film.

8. The substrate processing method according to claim 1, wherein the thickness of the carbon-containing film is controlled based on the strength of the stress of the first stack.

9. The substrate processing method according to claim 1, wherein the carbon-containing film is a diamond-like carbon film.

10. The substrate processing method according to claim 1, further comprising the step of modifying the surface of the first stack after the step of forming the first stack and before the step of forming the carbon-containing film.

11. The substrate processing method according to claim 10, wherein the step of modifying the surface of the first laminate comprises making the surface of the first laminate hydrophobic.

12. The substrate processing method according to claim 1, further comprising the step of forming a second stack by stacking the carbon-containing film.

13. A method for forming a hard mask, comprising the steps of: preparing a substrate having a first stack in which first insulating films and second insulating films are alternately stacked; and forming a hard mask of a carbon-containing film on the first stack, wherein the direction of stress in the first stack is different from the direction of stress in the carbon-containing film, and the absolute value of the difference between the absolute value of the strength of stress in the first stack and the absolute value of the strength of stress in the carbon-containing film is 100 MPa or less.

14. The method for forming a hard mask according to claim 13, wherein the direction of stress in the first stack is tensile stress, and the direction of stress in the carbon-containing film is compressive stress.

15. The method for forming a hard mask according to claim 13, wherein the absolute value of the stress intensity of the first stack is 1 GPa or more, and the absolute value of the stress intensity of the carbon-containing film is 1 GPa or more.

16. The method for forming a hard mask according to claim 13, wherein the thickness of the carbon-containing film is controlled based on the strength of the stress of the first stack.

17. The method for forming a hard mask according to claim 13, wherein the carbon-containing film is a diamond-like carbon film.

18. The method for forming a hard mask according to claim 13, further comprising, after the step of forming the first stack and before the step of forming the carbon-containing film, a step of modifying the surface of the first stack.

19. The method for forming a hard mask according to claim 18, wherein the step of modifying the surface of the first stacked body comprises making the surface of the first stacked body hydrophobic.

20. A substrate processing system comprising: a first processing apparatus that forms a first stack of alternating first insulating films and second insulating films on a substrate; a second processing apparatus that hydrophobizes the surface of the first stack; a third processing apparatus that forms a carbon-containing film on the hydrophobized surface of the first stack; and a vacuum transfer chamber connected to the first processing apparatus, the second processing apparatus, and the third processing apparatus.

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