Substrate processing method, method of manufacturing semiconductor device, and microwave plasma apparatus

Abstract

To provide a substrate processing method for embedding a film in a recess, a method for manufacturing a semiconductor device, and a microwave plasma apparatus.SOLUTION: A substrate processing method comprising: preparing a substrate having a concavo-convex structure; forming a dielectric film containing at least silicon and nitrogen on the concavo-convex structure to form the dielectric film having a heterogeneous portion in a concave portion of the concavo-convex structure; and forming a protective film on a surface of the dielectric film by exposing the dielectric film to a first plasma containing an oxygen gas and forming a protective film including a cap layer that covers the heterogeneous portion by bonding an upper side of the heterogeneous portion of the concavo-convex structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing method, a semiconductor device manufacturing method, and a microwave plasma device. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing a semiconductor device, which includes the steps of: supplying a precursor substance to a substrate having a recess on its surface, the upper and side surfaces of which are made of a first material containing a first element and the bottom surface of which is made of a second material containing a second element different from the first element, thereby adsorbing at least a portion of the molecular structure of the precursor substance onto the surface of the first material in the recess, thereby forming a film-formation inhibitor layer on the surface of the first material; and supplying a film-formation substance to the substrate on which the film-formation inhibitor layer has been formed on the surface of the first material, thereby growing a film on the surface of the second material in the recess. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-165287 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a substrate processing method for filling a recess with a film, a semiconductor device manufacturing method, and a microwave plasma device. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect, there is provided a substrate processing method comprising the steps of: preparing a substrate having a concave-convex structure; forming a dielectric film containing at least silicon and nitrogen on the concave-convex structure, and forming the dielectric film having uneven portions in recesses of the concave-convex structure; and exposing the dielectric film to a first plasma containing oxygen gas to form a protective film on a surface of the dielectric film, and forming the protective film including a cap layer that bonds to the upper side of the uneven portions of the concave-convex structure and seals the uneven portions. [Effects of the Invention]

[0006] According to one aspect, it is possible to provide a substrate processing method for filling a recess with a film, a semiconductor device manufacturing method, and a microwave plasma device. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a flowchart showing an example of a substrate processing method. [Figure 2] 1 is a schematic cross-sectional view of an example of a substrate prepared in step S101. [Figure 3] 10 is an example of a schematic cross-sectional view of the substrate after the process in step S102. [Figure 4] 10 is an example of a schematic cross-sectional view of the substrate after the process in step S103. [Figure 5] 10 is an example of a schematic cross-sectional view of the substrate after the process in step S104. [Figure 6] 10 is an example of a schematic cross-sectional view of the substrate after the process in step S105. [Figure 7] 10 is an example of a schematic cross-sectional view of the substrate after the process in step S106. [Figure 8] 10 is a flowchart showing an example of a process for forming a cap layer. [Figure 9] 10 is a flowchart showing another example of a process for forming a cap layer. [Figure 10] 10 is a flowchart showing yet another example of the process of forming a cap layer. [Figure 11] 10 is a flowchart showing yet another example of the process of forming a cap layer. [Figure 12] 1 shows an example of a microwave plasma device for forming a cap layer. [Figure 13] FIG. 10 is a cross-sectional view showing an example of a processing result. DETAILED DESCRIPTION OF THE INVENTION

[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] An example of a substrate processing method according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a flowchart showing an example of the substrate processing method.

[0010] In step S101, a substrate having a layered structure is prepared. Figure 2 is an example of a schematic cross-sectional view of the substrate prepared in step S101.

[0011] A laminated structure is provided on the surface of the base material 100, in which first material layers 110 (Si layers) made of a first material and second material layers 120 (SiGe layers) made of a second material are alternately laminated. An insulating layer 130 is provided on the laminated structure of the first material layers 110 and the second material layers 120. In the example shown in Fig. 2, the laminated structure of the first material layers 110 and the second material layers 120 has the second material layer 120 formed as the bottom layer in contact with the base material 100, and the first material layer 110 formed as the top layer in contact with the insulating layer 130.

[0012] The substrate 100 is, for example, a silicon (Si) wafer.

[0013] The first material includes a first element. The first element is, for example, silicon (Si). In the following description, the first material layer 110 will be described as a silicon (Si) layer.

[0014] The second material layer 120 includes a first element and a second element. The first element is, for example, silicon (Si), and the second element is, for example, germanium (Ge). In the following description, the second material layer 120 is described as a silicon germanium (SiGe) layer.

[0015] The insulating layer 130 is made of an insulator, and examples of the insulator that can be used for the insulating layer 130 include silicon oxide (SiO2) and silicon nitride (SiN).

[0016] In the sidewall of the laminated structure of the first material layer 110 and the second material layer 120, a recess 150 is formed, with the depth direction being parallel to the surface of the substrate 100 (horizontal direction; direction perpendicular to the laminated direction; direction perpendicular to the sidewall of the laminated structure). Specifically, the sidewall of the second material layer 120 is formed more inward than the sidewall of the first material layer 110, thereby forming the recess 150. In other words, when viewed in the depth direction (horizontal direction) of the recess 150, a bottom surface 150a of the recess 150 is formed by the second material layer 120, and an upper side surface (one side surface) 150b1 of the recess 150, a lower side surface (the other side surface) 150b2 of the recess 150, and an upper surface 150c of the protrusion between the recesses 150 are formed by the first material layer 110. In other words, the laminated structure formed on the substrate has an uneven structure in which the first material layer 110 forms protrusions and the second material layer 120 forms recesses 150 on the sidewall of the laminated structure.

[0017] In step S102, a dielectric film 200 (SiOCN film) containing at least silicon (Si) and nitrogen (N) is formed on the uneven structure of the substrate by ALD (Atomic Layer Deposition). Figure 3 is an example of a schematic cross-sectional view of the substrate after processing in step S102.

[0018] Here, a precursor gas and a reactive gas are alternately supplied to form a dielectric film 200 containing at least silicon (Si) and nitrogen (N). Specifically, one cycle consists of a step of supplying a precursor gas to a substrate and causing the precursor gas to adsorb onto the surface of the uneven structure, and a step of supplying a reactive gas to the substrate and causing the reactive gas to react with the precursor gas adsorbed onto the surface of the uneven structure to form a dielectric film. This cycle is repeated a predetermined number of times. This allows the formation of a dielectric film 200 with a desired thickness. Alternatively, the step of supplying a reactive gas may be a step of generating plasma of the reactive gas and causing active species (ions, radicals, etc.) of the reactive gas to react with the precursor gas adsorbed onto the surface of the uneven structure to form a dielectric film.

[0019] The dielectric film 200 may also contain oxygen (O). The dielectric film 200 may also contain carbon (C). That is, the dielectric film 200 may be any of a SiCN film, a SiON film, and a SiOCN film.

[0020] 7, which will be described later, the dielectric film 200 is an interlayer insulating film disposed between layers of the first material layer 110, and is preferably a film made of a low-dielectric-constant material (low-k film). Specifically, the dielectric film 200 is preferably an SiOCN film or an SiCN film. In the following description, the dielectric film 200 will be described as an SiOCN film.

[0021] By forming the film using the ALD method, a conformal dielectric film 200 can be formed that conforms to the uneven structure formed on the sidewall of the stacked structure of the first material layer 110 and the second material layer 120.

[0022] On the other hand, when filling the recess 150 with the dielectric film 200, the ALD method is used to form the dielectric film 200 from the bottom surface 150a of the recess 150, and the dielectric film 200 (201, 202) is also formed from the upper side surface 150b1 of the recess 150 and the lower side surface 150b2 of the recess 150.

[0023] Therefore, in the dielectric film 200 embedded in the recess 150, an uneven portion 151 is formed, which includes a gap (opening, void, etc.) between the dielectric film 201 formed from the upper side surface (one side surface) 150b1 and the dielectric film 202 formed from the lower side surface (the other side surface) 150b2, a seam (not shown) where the dielectric film 201 formed from the upper side surface (one side surface) 150b1 and the dielectric film 202 formed from the lower side surface (the other side surface) 150b2 are joined, etc. Note that the uneven portion 151 formed between the dielectric film 201 and the dielectric film 202 may be a seam or a gap (opening, void, etc.).

[0024] In step S103, a cap layer 301 is formed to close the inlet side of the non-uniform portion 151. Fig. 4 is an example of a schematic cross-sectional view of the substrate after the process in step S103.

[0025] Here, plasma of a gas containing oxygen (O) is generated and supplied to the substrate, and the surface of the dielectric film 200 formed in the uneven structure is exposed to the plasma of the gas containing oxygen (O). As a result, nitrogen (N) in the dielectric film 200 (SiOCN film) is replaced with oxygen (O). That is, the surface of the dielectric film 200 is oxidized by the oxygen plasma, and a protective film 300 is formed on the surface of the dielectric film 200. Furthermore, microwave plasma can be used as the plasma for forming the protective film 300.

[0026] Furthermore, as the protective film 300 is formed, the dielectric film 201 (see FIG. 3) formed from the upper side surface (one side surface) 150b1 of the recess 150 and the dielectric film 202 (see FIG. 3) formed from the lower side surface (the other side surface) 150b2 of the recess 150 are bonded (reformed) near the entrance of the non-uniform portion 151. As a result, a cap layer 301 is formed in the protective film 300, closing the entrance side of the non-uniform portion 151 (the upper side when the depth direction of the recess 150 is viewed downward).

[0027] In step S104, an etching process is performed. Fig. 5 is an example of a schematic cross-sectional view of the substrate after the process in step S104.

[0028] The etching process removes a portion of the dielectric film 200 and the protective film 300. As a result, the left and right sidewalls (top surface 150c shown in FIG. 2) of the first material layer 110 are exposed. Meanwhile, the dielectric film 200 including the cap layer 301 is embedded in the recess 150 (see FIG. 2). In addition, the non-uniform portion 151 of the dielectric film 200 is closed by the cap layer 301.

[0029] In step S105, a source layer 501 and a drain layer 502 are formed. Fig. 6 is an example of a schematic cross-sectional view of the substrate after the process in step S105.

[0030] The source layer 501 and the drain layer 502 are made of a conductive material such as a metal. The source layer 501 is formed so as to be connected to one end of the first material layer 110. The drain layer 502 is formed so as to be connected to the other end of the first material layer 110.

[0031] In step S106, the second material layer 120 (SiGe layer) is removed by etching. Figure 7 is an example of a schematic cross-sectional view of the substrate after the process of step S106.

[0032] 7, the second material layer 120 (SiGe layer) is selectively removed by etching from the stacked structure of the first material layer 110 (Si layer) and the second material layer 120 (SiGe layer), forming a gap 160. The upper and outer sides of the source layer 501 and the drain layer 502 are covered in advance with a protective film (not shown) to prevent damage due to etching.

[0033] The dielectric film 200 including the cap layer 301 functions as an inner spacer for maintaining the nanosheet structure of the first material layer 110 (Si layer) when the second material layer 120 (SiGe layer) is removed to form the voids 160. The dielectric film 200 including the cap layer 301 also functions as an interlayer insulating film (low-k film) in a semiconductor device structure.

[0034] Here, when etching the second material layer 120 (SiGe layer), the etchant may be drawn into the uneven portions 151 such as seams and gaps from the voids 160 and reach the source layer 501 and the drain layer 502, which may cause etching damage to the source layer 501 and the drain layer 502.

[0035] In contrast, in this embodiment, the cap layer 301 that closes the non-uniform portion 151 is provided, and therefore the etchant that has been taken into the non-uniform portion 151 from the void 160 is sealed by the cap layer 301. This makes it possible to prevent damage to the source layer 501 and the drain layer 502 when etching the second material layer 120 (SiGe layer).

[0036] Thereafter, a semiconductor device structure is formed through a process of forming a gate layer, etc. As the semiconductor device structure, a transistor with a GAA (Gate All Around) structure, etc. is formed.

[0037] In this way, the surface of the dielectric film 200 (SiOCN film) formed so as to fill the recesses 150 of the uneven structure is modified with oxygen plasma to form a protective film 300, and a cap layer 301 that closes the uneven portions 151 can be formed (see S101 to S103).

[0038] This makes it possible to prevent the source layer 501 and the drain layer 502 from being damaged by etching when the second material layer 120 (SiGe layer) is etched.

[0039] 2 may be performed by a substrate processing system. The substrate processing system may include a film forming apparatus (see S102) that forms a dielectric film 200 on a substrate, a microwave plasma apparatus (see S103) that forms a protective film 300 by microwave plasma, a first etching apparatus (see S104) that removes a portion of the dielectric film 200 and the protective film 300, a film forming apparatus (see S105) that forms a source layer 501 and a drain layer 502, a second etching apparatus (see S106) that etches the second material layer 120, and a control device that controls these apparatuses.

[0040] Next, the process of forming the cap layer 301 in step S103 will be described with reference to FIGS.

[0041] FIG. 8 is a flowchart showing an example of a process for forming the cap layer 301.

[0042] In step S201, a cap layer 301 is formed by surface oxidation plasma.

[0043] Here, a first plasma of a gas containing oxygen (O) is generated and supplied to the substrate, and the surface of the dielectric film 200 formed in the uneven structure is exposed to the first plasma of the gas containing oxygen (O). As a result, nitrogen (N) in the dielectric film 200 (SiOCN film) is replaced with oxygen (O). That is, the surface of the dielectric film 200 is oxidized by the oxygen plasma, and a protective film 300 is formed on the surface of the dielectric film 200. Furthermore, microwave plasma can be used as the plasma for forming the protective film 300.

[0044] Furthermore, as the protective film 300 is formed, the dielectric film 201 (see FIG. 3) formed from the upper side surface (one side surface) 150b1 of the recess 150 and the dielectric film 202 (see FIG. 3) formed from the lower side surface (the other side surface) 150b2 of the recess 150 are bonded (reformed) near the entrance of the non-uniform portion 151. As a result, a cap layer 301 is formed in the protective film 300, closing the entrance side of the non-uniform portion 151 (the upper side when the depth direction of the recess 150 is viewed downward).

[0045] An example of a recipe for the first plasma is shown below.

[0046] <First Plasma> Pressure inside the processing vessel: 200Pa to 1000Pa Processing gas: O2 gas (100sccm~1000sccm) Microwave power: 2000W~4000W

[0047] FIG. 9 is a flowchart showing another example of the process for forming the cap layer 301.

[0048] In step S211, a cap layer 301 is formed by surface oxidation plasma.

[0049] Here, similarly to step S201, a first plasma of a gas containing oxygen (O) is generated and supplied to the substrate, and the surface of the dielectric film 200 formed in the concave-convex structure is exposed to the first plasma of the gas containing oxygen (O). As a result, nitrogen (N) in the dielectric film 200 (SiOCN film) is replaced with oxygen (O). That is, the surface of the dielectric film 200 is oxidized by the oxygen plasma, and a protective film 300 is formed on the surface of the dielectric film 200. Furthermore, microwave plasma can be used as the plasma for forming the protective film 300.

[0050] Furthermore, as the protective film 300 is formed, the dielectric film 201 (see FIG. 3) formed from the upper side surface (one side surface) 150b1 of the recess 150 and the dielectric film 202 (see FIG. 3) formed from the lower side surface (the other side surface) 150b2 of the recess 150 are bonded (reformed) near the entrance of the non-uniform portion 151. As a result, a cap layer 301 is formed in the protective film 300, closing the entrance side of the non-uniform portion 151 (the upper side when the depth direction of the recess 150 is viewed downward).

[0051] In step S212, the protective film 300 including the cap layer 301 is densified (high density) by surface oxidation plasma.

[0052] Here, a second plasma of a gas containing oxygen (O) is generated and supplied to the substrate, and the surface of the dielectric film 200 formed in the uneven structure is exposed to the second plasma of the gas containing oxygen (O). This densifies the protective film 300 including the cap layer 301. This improves the etching resistance of the cap layer 301 against the etchant used in step S106. It also prevents damage to the source layer 501 and the drain layer 502 during etching of the second material layer 120 (SiGe layer). In addition, microwave plasma can be used as the plasma.

[0053] Here, the first plasma generates oxygen plasma at a higher pressure and higher O concentration than the second plasma. As a result, the radical species generated by the first plasma are dominated by "Op." These radical species react deep within the dielectric film 200. This allows the cap layer 301 to be formed effectively.

[0054] Furthermore, the second plasma generates oxygen plasma at a lower pressure and a lower O concentration than the first plasma. H gas may also be added to O gas. This causes "O1d" to be dominant among the radical species generated by the second plasma. Furthermore, when H gas is added, OH radicals are also generated. These radical species can remove hydrogen (H) from the dielectric film 200 and the protective film 300, thereby densifying (increasing the density of) the dielectric film 200 and the protective film 300 (including the cap layer 301).

[0055] An example of a recipe for the second plasma is shown below.

[0056] <Second Plasma> Pressure inside the processing vessel: 60Pa to 160Pa Processing gas: O2 gas (5sccm to 50sccm) H2 gas (0sccm to 10sccm) Microwave power: 2000W~4000W

[0057] FIG. 10 is a flowchart showing yet another example of the process for forming the cap layer 301.

[0058] In step S221, the cap layer 301 is formed by surface oxidation plasma.

[0059] Here, similarly to steps S201 and S211, a first plasma of a gas containing oxygen (O) is generated and supplied to the substrate, and the surface of the dielectric film 200 formed in the concave-convex structure is exposed to the first plasma of the gas containing oxygen (O). As a result, nitrogen (N) in the dielectric film 200 (SiOCN film) is replaced with oxygen (O). That is, the surface of the dielectric film 200 is oxidized by the oxygen plasma, and a protective film 300 is formed on the surface of the dielectric film 200. Furthermore, microwave plasma can be used as the plasma for forming the protective film 300.

[0060] Furthermore, as the protective film 300 is formed, the dielectric film 201 (see FIG. 3) formed from the upper side surface (one side surface) 150b1 of the recess 150 and the dielectric film 202 (see FIG. 3) formed from the lower side surface (the other side surface) 150b2 of the recess 150 are bonded (reformed) near the entrance of the non-uniform portion 151. As a result, a cap layer 301 is formed in the protective film 300, closing the entrance side of the non-uniform portion 151 (the upper side when the depth direction of the recess 150 is viewed downward).

[0061] In step S222, the protective film 300 including the cap layer 301 is doped with carbon (C) and / or nitrogen (N) by a third plasma containing a carbon-containing gas and / or a nitrogen-containing gas.

[0062] Plasma of a carbon (C)-containing gas is generated, and the substrate is exposed to the plasma of the carbon (C)-containing gas, thereby doping the dielectric film 200 and the protective film 300 (including the cap layer 301) with carbon (C). As the carbon (C)-containing gas, a hydrocarbon gas (CxHy) or the like can be used. Furthermore, microwave plasma can be used as the plasma.

[0063] Plasma of a nitrogen (N)-containing gas is generated, and the substrate is exposed to the plasma of the nitrogen (N)-containing gas, thereby doping the dielectric film 200 and the protective film 300 (including the cap layer 301) with nitrogen (N). NH3 or the like can be used as the nitrogen (N)-containing gas. Microwave plasma can also be used as the plasma.

[0064] An example of a third plasma recipe is shown below.

[0065] <Third Plasma> Pressure inside the processing vessel: 10Pa to 1000Pa Processing gas: Carbon-containing gas (CxHy gas (1sccm to 100sccm)) Nitrogen-containing gas (N2 gas (10sccm~500sccm)) Microwave power: 1500W~4000W

[0066] In step S221, when the protective film 300 including the cap layer 301 is formed on the surface of the dielectric film 200, nitrogen (N) and carbon (C) are removed from the film. Therefore, in step S222, the dielectric film 200 and the protective film 300 (including the cap layer 301) are doped with carbon (C) and / or nitrogen (N), thereby adjusting the concentration ratio (composition ratio) of carbon (C) and / or nitrogen (N) in the film. This makes it possible to adjust the dielectric constant of the dielectric film 200 including the cap layer 301 used as an interlayer insulating film (low-k film).

[0067] FIG. 11 is a flowchart showing yet another example of the process for forming the cap layer 301.

[0068] In step S231, the dielectric film 200 is doped with carbon (C) and / or nitrogen (N) by a fourth plasma containing a carbon-containing gas and / or a nitrogen-containing gas.

[0069] Plasma of a carbon (C)-containing gas is generated, and the substrate is exposed to the plasma of the carbon (C)-containing gas, thereby doping carbon (C) into the dielectric film 200. As the carbon (C)-containing gas, a hydrocarbon gas (CxHy) or the like can be used. Also, microwave plasma can be used as the plasma.

[0070] Plasma of a nitrogen (N)-containing gas is generated, and the substrate is exposed to the plasma of the nitrogen (N)-containing gas, thereby doping nitrogen (N) into the dielectric film 200. NH3 or the like can be used as the nitrogen (N)-containing gas. Microwave plasma can also be used as the plasma.

[0071] An example of a fourth plasma recipe is shown below.

[0072] <The Fourth Plasma> Pressure inside the processing vessel: 10Pa to 1000Pa Processing gas: Carbon-containing gas (CxHy gas (1sccm to 100sccm)) Nitrogen-containing gas (N2 gas (10sccm~500sccm)) Microwave power: 1500W~4000W

[0073] In step S232, a cap layer 301 is formed by surface oxidation plasma.

[0074] Here, similarly to steps S201, S211, and S221, a first plasma of a gas containing oxygen (O) is generated and supplied to the substrate, and the surface of the dielectric film 200 formed in the concave-convex structure is exposed to the first plasma of the gas containing oxygen (O). As a result, nitrogen (N) in the dielectric film 200 (SiOCN film) is replaced with oxygen (O). That is, the surface of the dielectric film 200 is oxidized by the oxygen plasma, and a protective film 300 is formed on the surface of the dielectric film 200. Furthermore, microwave plasma can be used as the plasma for forming the protective film 300.

[0075] Furthermore, as the protective film 300 is formed, the dielectric film 201 (see FIG. 3) formed from the upper side surface (one side surface) 150b1 of the recess 150 and the dielectric film 202 (see FIG. 3) formed from the lower side surface (the other side surface) 150b2 of the recess 150 are bonded (reformed) near the entrance of the non-uniform portion 151. As a result, a cap layer 301 is formed in the protective film 300, closing the entrance side of the non-uniform portion 151 (the upper side when the depth direction of the recess 150 is viewed downward).

[0076] By doping the surface of the dielectric film 200 with nitrogen (N) in advance, the bonding between the dielectric film 201 and the dielectric film 202 is promoted, and the cap layer 301 can be formed favorably.

[0077] Furthermore, by doping the dielectric film 200 with carbon (C) and / or nitrogen (N) in advance, it is possible to adjust the concentration ratio (composition ratio) of carbon (C) and / or nitrogen (N) in the film after forming the protective film 300. This makes it possible to adjust the dielectric constant of the dielectric film 200 including the cap layer 301 used as an interlayer insulating film (low-k film).

[0078] In step S231, the dielectric film 200 is doped with carbon (C) and / or nitrogen (N) by plasma, but this is not limiting. For example, a dielectric film adjusted to increase the carbon (C) and / or nitrogen (N) concentration on the surface of the dielectric film 200 may be formed by the ALD method. Even in this case, the carbon (C) and / or nitrogen (N) concentration on the surface of the dielectric film 200 is increased in advance, thereby adjusting the concentration ratio (composition ratio) of carbon (C) and / or nitrogen (N) in the protective film 300 including the cap layer 301.

[0079] [Microwave plasma device] Next, the microwave plasma apparatus 1 that performs the process of forming the cap layer 301 in step S103 will be described with reference to Fig. 12. Fig. 12 is a schematic cross-sectional view showing an example of the microwave plasma apparatus 1 according to an embodiment of the present disclosure. The microwave plasma apparatus 1 illustrated in Fig. 12 is configured as, for example, an RLSA (registered trademark) microwave plasma type plasma processing apparatus.

[0080] The microwave plasma device 1 includes a device main body 10 and a control unit 11 that controls the device main body 10. The device main body 10 includes a chamber 601, a stage 602, a microwave introduction mechanism 603, a gas supply mechanism 604, and an exhaust mechanism 605.

[0081] The chamber 601 is formed in a substantially cylindrical shape, and an opening 610 is formed in the approximate center of a bottom wall 601a of the chamber 601. An exhaust chamber 611 that communicates with the opening 610 and protrudes downward is provided in the bottom wall 601a. ​​An opening 617 through which the substrate W passes is formed in a side wall 601s of the chamber 601, and the opening 617 is opened and closed by a gate valve 618. The chamber 601 is an example of a processing vessel.

[0082] A substrate W to be processed is placed on a stage 602. The stage 602 is generally disk-shaped and made of ceramics such as AlN. The stage 602 is supported by a cylindrical support member 612 made of ceramics such as AlN that extends upward from approximately the center of the bottom of an exhaust chamber 611. An edge ring 613 is provided on the outer edge of the stage 602 so as to surround the substrate W placed on the stage 602. Furthermore, inside the stage 602, lifting pins (not shown) for lifting and lowering the substrate W are provided so as to be able to protrude and retract from the upper surface of the stage 602.

[0083] Furthermore, a resistance heater 614 is embedded inside the stage 602, and the heater 614 heats the substrate W placed on the stage 602 in accordance with power supplied from a heater power supply 615. A thermocouple (not shown) is also inserted into the stage 602, and the temperature of the substrate W can be controlled to, for example, 350 to 850°C based on a signal from the thermocouple. Furthermore, an electrode 616 having a size approximately the same as that of the substrate W is embedded above the heater 614 inside the stage 602, and a bias power supply 619 is electrically connected to the electrode 616. The bias power supply 619 supplies bias power of a predetermined frequency and magnitude to the electrode 616. The bias power supplied to the electrode 616 attracts ions to the substrate W placed on the stage 602. Note that the bias power supply 619 may not be provided depending on the characteristics of the plasma processing.

[0084] Microwave introduction mechanism 603 is provided at the top of chamber 601 and has antenna 621, microwave output unit 622, and microwave transmission mechanism 623. Antenna 621 has a large number of slots 621a that are through-holes. Microwave output unit 622 outputs microwaves. Microwave transmission mechanism 623 guides the microwaves output from microwave output unit 622 to antenna 621.

[0085] A dielectric window 624 made of a dielectric material is provided below the antenna 621. The dielectric window 624 is supported by a support member 632 that is ring-shaped and provided at the top of the chamber 601. A slow-wave plate 626 is provided above the antenna 621. A shield member 625 is provided above the antenna 621. A flow path (not shown) is provided inside the shield member 625, and the shield member 625 cools the antenna 621, the dielectric window 624, and the slow-wave plate 626 by a fluid such as water that flows through the flow path.

[0086] The antenna 621 is formed of, for example, a copper plate or aluminum plate with a silver or gold-plated surface, and has a plurality of slots 621a for radiating microwaves arranged in a predetermined pattern. The arrangement pattern of the slots 621a is appropriately set so that the microwaves are radiated uniformly. An example of a suitable pattern is a radial line slot, in which two slots 621a arranged in a T-shape form a pair, and multiple pairs of slots 621a are arranged concentrically. The length and arrangement interval of the slots 621a are appropriately determined depending on the effective wavelength (λg) of the microwaves. The slots 621a may also have other shapes, such as a circular shape or an arc shape. Furthermore, the arrangement of the slots 621a is not particularly limited, and may be arranged in a spiral or radial shape in addition to a concentric shape. The pattern of the slots 621a is appropriately set so that microwave radiation characteristics that obtain a desired plasma density distribution are achieved.

[0087] Slow-wave plate 626 is made of a dielectric material having a dielectric constant greater than that of a vacuum, such as quartz, ceramics (Al2O3), polytetrafluoroethylene, or polyimide. Slow-wave plate 626 has the function of shortening the wavelength of the microwave compared to that in a vacuum, thereby reducing the size of antenna 621. Dielectric window 624 is also made of a similar dielectric material.

[0088] The thicknesses of the dielectric window 624 and the slow-wave plate 626 are adjusted so that the equivalent circuit formed by the slow-wave plate 626, the antenna 621, the dielectric window 624, and the plasma satisfies the resonance condition. The phase of the microwave can be adjusted by adjusting the thickness of the slow-wave plate 626. By adjusting the thickness of the slow-wave plate 626 so that the junction of the antenna 621 becomes the "antinode" of the standing wave, microwave reflection can be minimized and the microwave radiation energy can be maximized. Furthermore, by using the same material for the slow-wave plate 626 and the dielectric window 624, interface reflection of the microwave can be prevented.

[0089] The microwave output unit 622 has a microwave oscillator. The microwave oscillator may be a magnetron type or a solid-state type. The frequency of the microwave generated by the microwave oscillator is, for example, 300 MHz to 10 GHz. As an example, the microwave output unit 622 outputs a microwave of 2.45 GHz using a magnetron type microwave oscillator. Microwaves are an example of electromagnetic waves.

[0090] The microwave transmission mechanism 623 includes a waveguide 627 and a coaxial waveguide 628. It may further include a mode conversion mechanism. The waveguide 627 guides the microwaves output from the microwave output unit 622. The coaxial waveguide 628 includes an inner conductor connected to the center of the antenna 621 and an outer conductor outside the inner conductor. The mode conversion mechanism is provided between the waveguide 627 and the coaxial waveguide 628. The microwaves output from the microwave output unit 622 propagate through the waveguide 627 in TE mode and are converted from TE mode to TEM mode by the mode conversion mechanism. The microwaves converted to TEM mode propagate through the coaxial waveguide 628 to the slow-wave plate 626 and are radiated from the slow-wave plate 626 into the chamber 601 through the slot 621a of the antenna 621 and the dielectric window 624. Incidentally, a tuner (not shown) for matching the impedance of the load (plasma) in the chamber 601 to the output impedance of the microwave output part 622 is provided midway along the waveguide 627.

[0091] The gas supply mechanism 604 includes a shower ring 642 that is ring-shaped and arranged along the inner wall of the chamber 601. The shower ring 642 includes a ring-shaped flow channel 666 arranged therein and a number of outlets 667 that are connected to the flow channel 666 and open to the inside of the channel 666. A gas supply unit 663 is connected to the flow channel 666 via a pipe 661. The gas supply unit 663 includes a number of gas sources and a number of flow rate controllers. In one embodiment, the gas supply unit 663 is configured to supply at least one process gas to the shower ring 642 from a corresponding gas source via a corresponding flow rate controller. The gas supplied to the shower ring 642 is then supplied into the chamber 601 through the multiple outlets 667.

[0092] When a graphene film is formed on the substrate W, the gas supply unit 663 supplies oxygen gas and a rare gas, the flow rates of which are controlled to predetermined values, into the chamber 601 via the shower ring 642. In this embodiment, the oxygen gas is, for example, O gas. In this embodiment, the rare gas is, for example, Ar gas.

[0093] The exhaust mechanism 605 includes an exhaust chamber 611, an exhaust pipe 681 provided on the side wall of the exhaust chamber 611, and an exhaust device 682 connected to the exhaust pipe 681. The exhaust device 682 includes a vacuum pump, a pressure control valve, and the like.

[0094] The control unit 11 has a memory, a processor, and an input / output interface. The memory stores programs to be executed by the processor and recipes including conditions for each process. The processor executes the programs read from the memory and controls each part of the device main body 10 via the input / output interface based on the recipes stored in the memory.

[0095] For example, the control unit 11 controls each unit of the microwave plasma device 1 to form the above-mentioned cap layer 301. To cite a detailed example, the control unit 11 executes a step of loading into the chamber 601 a substrate W having a dielectric film 200 embedded in the recess 150 and including a non-uniform portion 151. The control unit 11 executes a step of supplying an oxygen-containing gas into the chamber 601 and forming a protective film 300 on the surface of the dielectric film 200 with plasma of the oxygen-containing gas, and forming the protective film 300 including the cap layer 301 that bonds to the upper side of the non-uniform portion 151 and covers the non-uniform portion 151.

[0096] The microwave plasma device 1 executes steps (S103, S201, S211, S221, S232) of generating a first plasma and processing the substrate W to form a protective film 300 including a cap layer 301. The microwave plasma device 1 may also be configured to execute steps (S212) of generating a second plasma and processing the substrate W, (S222) of generating a third plasma and processing the substrate W, and (S231) of generating a fourth plasma and processing the substrate W.

[0097] Next, a process for forming the protective film 200 using plasma of a gas containing oxygen (O) will be described with reference to Fig. 13. Fig. 13 is a cross-sectional view showing an example of the process result.

[0098] 13(a) is an example of a TEM image after the formation of an SiOCN film. Here, an SiOCN film (dielectric film 200) is formed by the ALD method on the Si layer (first material layer 110) in which the recesses are formed by the process of step S102. As a result, the SiOCN film is embedded in the recesses of the Si layer. Here, the SiOCN film (dielectric film 200) is formed on the bottoms and side surfaces 150b1, 150b2 of the recesses, thereby forming non-uniform portions 151 including seams, gaps, etc.

[0099] 13(b) and 13(c) are examples of TEM images after the formation of the protective film 300. Here, by the process of step S103, plasma of a gas containing oxygen (O) is generated, and the surface of the SiOCN film (dielectric film 200) is exposed to the plasma of the gas containing oxygen (O). In this way, the protective film 200 is formed.

[0100] In FIG. 13(b), a mixed gas of 1746 sccm of Ar gas and 54 sccm of O2 gas was used as the gas containing oxygen (O), plasma was generated at 1 Torr, and the surface of the SiOCN film (dielectric film 200) was exposed to the plasma for 1260 seconds.

[0101] In FIG. 13(c), 1000 sccm of O 2 gas was used as the gas containing oxygen (O), plasma was generated at 5 Torr, and the surface of the SiOCN film (dielectric film 200) was exposed to the plasma for 1260 seconds.

[0102] As shown by comparing FIG. 13(a) with FIG. 13(b) and FIG. 13(c), by forming the protective film 300, the uneven portions 151 including seams, gaps, etc. are closed.

[0103] Furthermore, as shown by comparing FIG. 13(b) and FIG. 13(c), the higher the pressure and the larger the amount of oxygen, the deeper the protective film 200 can be formed.

[0104] The above describes a substrate processing method for forming a film on a concave-convex structure, 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. [Explanation of symbols]

[0105] 1. Microwave plasma device 10. Device body 11 Control section 100 Base material 110 1st material layer 120 2nd material layer 130 Insulating layer 150 recess 150a bottom 150b1 Side (one side) 150b2 Side (other side) 150c top 151 Uneven Part 160 void 200 Dielectric Film 201 Dielectric film 202 Dielectric film 300 Protective film 301 Cap Layer 501 Source Layer 502 Drain layer 601 Chamber (processing vessel) 602 Stage 603 Microwave introduction mechanism 604 Gas supply mechanism 605 Exhaust mechanism W substrate

Claims

1. preparing a substrate having a relief structure; forming a dielectric film containing at least silicon and nitrogen on the uneven structure, and forming the dielectric film having an uneven portion in a recess of the uneven structure; and exposing the dielectric film to a first plasma containing oxygen gas to form a protective film on the surface of the dielectric film, and forming the protective film including a cap layer that bonds to an upper side of the uneven portion of the uneven structure and closes the uneven portion. Substrate processing method.

2. the first plasma replaces nitrogen in the dielectric film with oxygen; The substrate processing method according to claim 1 .

3. After the step of forming the protective film including the cap layer, modifying the cap layer by exposing it to a second plasma that includes oxygen gas and is different from the first plasma; The substrate processing method according to claim 1 .

4. the second plasma increases the film density of the cap layer; The substrate processing method according to claim 3 .

5. After the step of forming the protective film including the cap layer, modifying the protective film by exposing it to a third plasma containing a carbon-containing gas and / or a nitrogen-containing gas; The substrate processing method according to claim 1 .

6. the third plasma dopes the protective film with carbon and / or nitrogen; The substrate processing method according to claim 5 .

7. After the step of forming the dielectric film and before the step of forming the protective film including the cap layer, modifying the dielectric film by exposing it to a fourth plasma containing a carbon-containing gas and / or a nitrogen-containing gas; The substrate processing method according to claim 1 .

8. the fourth plasma dopes the dielectric film with carbon and / or nitrogen; The substrate processing method according to claim 7 .

9. the first plasma is a microwave plasma; The substrate processing method according to claim 1 .

10. The step of forming the dielectric film includes: The film is formed by the ALD method. The substrate processing method according to claim 1 .

11. The dielectric film is SiOCN film or SiCN film, The substrate processing method according to claim 1 .

12. preparing a substrate having a layered structure in which Si layers and SiGe layers are alternately stacked, the substrate having an uneven structure in which the Si layers form convex portions and the SiGe layers form concave portions on side walls of the layered structure; forming a dielectric film containing at least silicon and nitrogen on the uneven structure, and forming the dielectric film having an uneven portion in a recess of the uneven structure; and exposing the dielectric film to a first plasma containing oxygen gas to form a protective film on the surface of the dielectric film, and forming a protective film including a cap layer that bonds to an upper side of the uneven portion of the uneven structure and closes the uneven portion. A method for manufacturing a semiconductor device.

13. A processing vessel; a stage disposed in the processing chamber and on which a substrate is placed; a gas supply mechanism for supplying a processing gas into the processing chamber; a microwave introduction mechanism for generating plasma of a processing gas in the processing vessel; a control unit, The control unit Control is performed to prepare a substrate on which a dielectric film containing silicon and nitrogen is formed, the dielectric film including a concave-convex structure and an uneven portion in a concave portion; the gas supply mechanism is controlled to supply a gas containing oxygen as a processing gas to the processing vessel; the microwave introduction mechanism is controlled to generate a first plasma of the gas containing oxygen; and the substrate is exposed to the first plasma to form a protective film on the surface of the dielectric film, and the protective film is controlled to include a cap layer that bonds to an upper side of the uneven portion of the uneven structure and closes the uneven portion. Microwave plasma device.

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