Substrate processing method and plasma processing device

Abstract

The present invention provides a substrate processing method and plasma processing apparatus for forming an organic film at the atomic layer level. In an exemplary embodiment, a substrate processing method is provided. The substrate processing method includes: a) providing a substrate into a chamber; and b) forming an organic film on the surface of the substrate. b) includes two steps b1) and b2). b1) supplying a first gas containing an organic compound into the chamber to form a precursor layer on the substrate. b2) supplying a second gas containing a modifying gas into the chamber to apply energy to at least one of the precursor layer and the second gas to modify the precursor layer, thereby forming an organic film on the substrate.

Description

Technical Field

[0001] Illustrative embodiments of the present invention relate to a substrate processing method and a plasma processing apparatus. Background Art

[0002] In the manufacture of electronic devices, micro patterns are sometimes formed by etching. Patent Document 1 discloses a method for forming micro patterns using a silicon oxide film. In the method disclosed in Patent Document 1, a photoresist pattern is formed on a material film on which the micro pattern is to be formed, and a silicon oxide film is evaporated on the photoresist pattern. The silicon oxide film is formed conformally and thinly in a manner that does not damage the underlying photoresist pattern. Next, dry etching is performed on the lower film. In this dry etching, spacers are first formed on the sidewalls of the photoresist pattern, and then a polymer film is formed on the photoresist pattern.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 2004-80033 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] The present invention provides a technique for forming an organic film.

[0008] Technical solutions to technical problems

[0009] In an exemplary embodiment, a substrate processing method is provided. The substrate processing method includes steps a) and b). Step a) is a step of providing a substrate into a chamber. Step b) is a step of forming an organic film on the surface of the substrate. Step b) includes steps b1) and b2). Step b1) is a step of supplying a first gas containing an organic compound into the chamber to form a precursor layer on the substrate. Step b2) is a step of supplying a second gas containing a modifying gas into the chamber to modify the precursor layer by applying energy to at least one of the precursor layer and the second gas, thereby forming an organic film on the substrate.

[0010] Effects of the Invention

[0011] According to the present invention, a technique for forming an organic film can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a flow chart of an exemplary embodiment of a substrate processing method.

[0013] Figure 2 This is a summary of the examples that can be Figure 1A diagram of the plasma processing apparatus used in the process is shown.

[0014] Figure 3 It is an example of accompanying Figure 1 Multiple cross sections of a substrate showing the execution of the process are shown.

[0015] Figure 4 It indicates an example of accompanying Figure 1 A diagram showing multiple chemical formulas of various gases and products of the execution of the process.

[0016] Figure 5 It indicates an example of accompanying Figure 1 A diagram showing multiple chemical formulas of various gases and products of the execution of the process.

[0017] Figure 6 Example accompanying Figure 1 Multiple cross sections of a substrate showing the execution of the process are shown.

[0018] Figure 7 is used to explain in more detail Figure 1 FIG. 1 is a diagram showing the execution of the process for the formation of an organic film.

[0019] Figure 8 It is an example of accompanying Figure 1 Multiple cross sections of a substrate showing the execution of the process are shown.

[0020] Figure 9 is a flow chart of another exemplary embodiment of a substrate processing method.

[0021] Figure 10 It is an example of accompanying Figure 9 Multiple cross sections of a substrate showing the execution of the process are shown.

[0022] Figure 11 It is an example of accompanying Figure 9 Several other cross-sections of a substrate are shown for implementation of the process.

[0023] Figure 12 is a flow chart of another exemplary embodiment of a substrate processing method.

[0024] Figure 13 It is an example of accompanying Figure 12 Multiple cross sections of a substrate showing the execution of the process are shown.

[0025] Figure 14 It is an example of accompanying Figure 12 Several other cross-sections of a substrate are shown for implementation of the process.

[0026] Description of Reference Numerals

[0027] 1…Plasma processing device; 10…Chamber; 10s…Internal space; 12…Chamber body; 12e…Exhaust port; 12g…Gate valve; 12p…Passage; 13…Support; 14…Support platform; 16…Electrode plate; 18…Lower electrode; 18f…Flow path; 20…Electrostatic chuck; 20p…DC power supply; 20s…Switch; 22a…Pipe; 22b…Pipe; 24…Gas supply line; 25…Edge ring; 30…Upper electrode; 32 ...components; 34...top plate; 34a...gas release hole; 36...support body; 36a...gas diffusion chamber; 36b...gas hole; 36c...gas inlet; 38...gas supply pipe; 40...gas source group; 41...valve group; 42...flow controller group; 46...shielding member; 48...baffle; 50...exhaust device; 52...exhaust pipe; 62...first high-frequency power supply; 64...second high-frequency power supply; 66...matching device; 68...matching device; 80...control unit. DETAILED DESCRIPTION

[0028] In the manufacture of electronic devices, technologies combining film formation and etching are used for applications such as CD control and as protective films and sacrificial films. Film formation requires a film with a high selectivity that is resistant to the combined etching. Furthermore, with the miniaturization of devices, etching also requires microscopic features. As described above, there is a demand for technologies that can control film formation and etching at the atomic level. Various exemplary embodiments are described below.

[0029] In an exemplary embodiment, a substrate processing method is provided. The substrate processing method includes steps a) and b). Step a) is a step of providing a substrate into a chamber. Step b) is a step of forming an organic film on the surface of the substrate. Step b) includes steps b1) and b2). Step b1) is a step of supplying a first gas containing an organic compound into the chamber to form a precursor layer on the substrate. Step b2) is a step of supplying a second gas containing a modifying gas into the chamber to modify the precursor layer by applying energy to at least one of the precursor layer and the second gas, thereby forming an organic film on the substrate.

[0030] In the illustrated embodiment, in step b2), an organic film is formed on the substrate by generating plasma of the second gas.

[0031] In the illustrated embodiment, step b1) and step b2) are repeated alternately.

[0032] In an exemplary embodiment, the substrate processing method further includes step c). Step c) is a step of etching the etched region using plasma of a processing gas after step b). The substrate includes the etched region and a patterned region formed on the etched region, wherein the etched region is surrounded by side surfaces of the patterned region.

[0033] In the illustrated embodiment, the substrate processing method further includes step d). Step d) is a step of etching the organic film extending on the etched region before step c) to leave the organic film along the side of the patterned region.

[0034] In the illustrated embodiment, the substrate processing method further includes steps e) and f). Step e) is a step prior to step b) in which the etched region is partially etched through the patterned region using plasma of a processing gas to form a recessed portion. Step f) is a step subsequent to step b) in which the recessed portion is further etched using plasma of a processing gas. The substrate includes an etched region and a patterned region formed on the etched region, wherein the etched region is surrounded by side surfaces of the patterned region.

[0035] In the illustrated embodiment, the precursor layer is not formed on the entire surface of the recessed portion in b1), and / or the precursor layer is not modified on the entire surface of the recessed portion in b2).

[0036] In the illustrated embodiment, the organic film has different thicknesses along the thickness direction of the substrate.

[0037] In the illustrated embodiment, the substrate processing method further includes steps g) and h). Step g) is a step of trimming the organic film after step b). Step h) is a step of etching the etched region through the patterned region using plasma of a process gas. The substrate includes an etched region and a patterned region formed on the etched region. The etched region is laterally surrounded by the patterned region. In step b), the organic film is formed to have varying thicknesses on the side surfaces along the thickness direction of the substrate.

[0038] In an exemplary embodiment, the substrate processing method further includes step i). Step i) is a step of forming a conformal organic film on the entire side surface before step b).

[0039] In the illustrated embodiment, the first gas includes at least one organic compound selected from the group consisting of epoxides, carboxylic acids, carboxylic acid halides, carboxylic anhydrides, isocyanates, and phenols.

[0040] In the illustrated embodiment, the second gas includes at least one modifying gas selected from the group consisting of an inorganic compound gas having an NH bond, an inert gas, a mixed gas of N 2 and H 2 , H 2 O gas, and a mixed gas of H 2 and O 2 .

[0041] In the illustrated embodiment, when the first gas includes at least one organic compound selected from the group consisting of carboxylic acid, carboxylic acid halide, and isocyanate, the second gas includes at least one modifying gas selected from the following gas group: an inorganic compound gas having an NH bond, an inert gas, a mixed gas of N2 and H2, H2O gas, and a mixed gas of H2 and O2.

[0042] In the illustrated embodiment, when the first gas includes at least one organic compound selected from the group consisting of epoxides, carboxylic anhydrides, and phenols, the second gas includes at least one modifying gas selected from the following gas group: an inorganic compound gas having an NH bond, an inert gas, and a mixed gas of N2 and H2.

[0043] In the exemplary embodiment, the inorganic compound gas having an NH bond is at least one selected from the group consisting of N 2 H 2 , N 2 H 4 , and NH 3 .

[0044] In the illustrated embodiment, the etched region includes a silicon-containing film.

[0045] In an exemplary embodiment, the step of forming the organic film and the step of performing etching are performed in the same chamber (in-situ) or in the same system (in-system) while maintaining a reduced pressure atmosphere.

[0046] In an exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a high-frequency power supply, a gas source group, and a control unit. The high-frequency power supply is configured to supply high frequency to an internal space of the chamber that can accommodate a substrate. The gas source group is configured to supply a first gas and a second gas to the internal space. The control unit is configured to control the high-frequency power supply and the gas source group. The first gas contains an organic compound. The second gas contains a modified gas. The control unit is configured to control the high-frequency power supply and the gas source group while the substrate is accommodated in the internal space, so as to perform steps a) and b). In step a), the first gas is supplied into the chamber to form a precursor layer on the substrate. In step b), the second gas is supplied into the chamber to supply energy to at least one of the precursor layer and the second gas to modify the precursor layer, thereby forming an organic film on the substrate.

[0047] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are given to the same or corresponding parts in the drawings.

[0048] Figure 1 The flowchart shown represents an exemplary embodiment of a substrate processing method (hereinafter referred to as method MT). Method MT is performed, for example, by using Figure 2The plasma processing apparatus shown is used to perform the treatment.

[0049] The plasma processing apparatus 1 includes a chamber 10. The chamber 10 defines an internal space 10s. The chamber 10 includes a chamber body 12. The chamber body 12 has a generally cylindrical shape. The chamber body 12 is formed, for example, from aluminum. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The film may be a ceramic such as aluminum oxide or yttrium oxide.

[0050] A passage 12p is formed in the side wall of the chamber body 12. The substrate W is transported between the internal space 10s and the outside of the chamber 10 through the passage 12p. The passage 12p can be opened and closed by a gate valve 12g provided along the side wall of the chamber body 12.

[0051] A support portion 13 is provided at the bottom of the chamber body 12. The support portion 13 is formed of an insulating material. The support portion 13 has a generally cylindrical shape. The support portion 13 extends upward from the bottom of the chamber body 12 within the internal space 10s. The support portion 13 has a support platform 14 at its top. The support platform 14 is configured to support the substrate W within the internal space 10s.

[0052] Support platform 14 includes a lower electrode 18 and an electrostatic chuck 20. Support platform 14 also includes an electrode plate 16. Electrode plate 16 is formed of a conductor such as aluminum and has a generally disk-shaped configuration. Lower electrode 18 is disposed on electrode plate 16. Lower electrode 18 is formed of a conductor such as aluminum and has a generally disk-shaped configuration. Lower electrode 18 is electrically connected to electrode plate 16.

[0053] The electrostatic chuck 20 is disposed on the lower electrode 18. A substrate W can be placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 includes a main body and an electrode. The main body of the electrostatic chuck 20 has a substantially disk-shaped structure and is formed of a dielectric. The electrode of the electrostatic chuck 20 is a film-shaped electrode disposed within the main body of the electrostatic chuck 20. The electrode of the electrostatic chuck 20 is connected to a DC power supply 20p via a switch 20s. When a voltage from the DC power supply 20p is applied to the electrode of the electrostatic chuck 20, an electrostatic attraction is generated between the electrostatic chuck 20 and the substrate W. This electrostatic attraction holds the substrate W on the electrostatic chuck 20.

[0054] An edge ring 25 is disposed on the periphery of the lower electrode 18 so as to surround the edge of the substrate W. The edge ring 25 improves the in-plane uniformity of the plasma treatment on the substrate W. The edge ring 25 can be formed of silicon, silicon carbide, quartz, or the like.

[0055] A flow path 18f is formed within lower electrode 18. A heat exchange medium (e.g., a refrigerant) is supplied to flow path 18f from a cooling unit (not shown) located outside chamber 10 via pipe 22a. The heat exchange medium supplied to flow path 18f is returned to the cooling unit via pipe 22b. In plasma processing apparatus 1, the temperature of substrate W placed on electrostatic chuck 20 can be adjusted by heat exchange between the heat exchange medium and lower electrode 18.

[0056] A gas supply line 24 is provided in the plasma processing apparatus 1. The gas supply line 24 supplies a heat transfer gas (eg, He gas) from a heat transfer gas supply mechanism to a position between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W.

[0057] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is disposed above the support platform 14. The upper electrode 30 is supported on the upper portion of the chamber body 12 via a member 32. The member 32 is formed of an insulating material. The upper electrode 30 and the member 32 close the upper opening of the chamber body 12.

[0058] The upper electrode 30 may include a top plate 34 and a support 36. The lower surface of the top plate 34 faces the inner space 10s and defines the inner space 10s. The top plate 34 may be formed of a low-resistance conductor or semiconductor that generates little Joule heat. A plurality of gas release holes 34a are formed in the top plate 34, penetrating the top plate 34 in the thickness direction.

[0059] The support body 36 detachably supports the top plate 34. The support body 36 is formed of a conductive material such as aluminum. A gas diffusion chamber 36a is provided within the support body 36. The support body 36 has a plurality of gas holes 36b extending downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are connected to the plurality of gas release holes 34a. A gas inlet 36c is formed in the support body 36. The gas inlet 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet 36c.

[0060] A valve group 41, a flow controller group 42, and a gas source group 40 are connected to the gas supply pipe 38. The gas source group 40, the valve group 41, and the flow controller group 42 constitute a gas supply unit. The gas source group 40 is configured to supply a first gas GS and a second gas that can contain an organic compound to the internal space 10s. The gas source group 40 includes a plurality of gas sources. The valve group 41 includes a plurality of on-off valves. The flow controller group 42 includes a plurality of flow controllers. Each of the plurality of flow controllers of the flow controller group 42 is a mass flow controller or a pressure-controlled flow controller. Each of the plurality of gas sources of the gas source group 40 is connected to the gas supply pipe 38 via a corresponding on-off valve of the valve group 41 and a corresponding flow controller of the flow controller group 42.

[0061] In the plasma processing apparatus 1, a shield 46 is detachably provided along the inner wall surface of the chamber body 12 and the outer periphery of the support portion 13. The shield 46 prevents reaction byproducts from adhering to the chamber body 12. The shield 46 is formed, for example, by forming a corrosion-resistant film on the surface of a base material formed of aluminum. The corrosion-resistant film can be made of a ceramic such as yttrium oxide.

[0062] A baffle 48 is provided between the support portion 13 and the sidewall of the chamber body 12. The baffle 48 is formed, for example, by forming a corrosion-resistant film (e.g., a film of yttrium oxide) on the surface of a base material formed of aluminum. Multiple through-holes are formed in the baffle 48. An exhaust port 12e is provided below the baffle 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 includes a pressure regulating valve and a vacuum pump such as a turbomolecular pump.

[0063] The plasma processing apparatus 1 includes a first high-frequency power supply 62 and a second high-frequency power supply 64. The first high-frequency power supply 62 is a power supply that generates a first high-frequency electric power. The first high-frequency power supply 62 is configured to supply a high frequency to the internal space 10s. The first high-frequency electric power has a frequency suitable for generating plasma. The frequency of the first high-frequency electric power is, for example, a frequency in the range of 27 to 100 [MHz]. The first high-frequency power supply 62 is connected to the lower electrode 18 via a matcher 66 and an electrode plate 16. The matcher 66 has a circuit that matches the output impedance of the first high-frequency power supply 62 with the impedance of the load side (lower motor 18 side). In addition, the first high-frequency power supply 62 can also be connected to the upper electrode 30 via the matcher 66. The first high-frequency power supply 62 constitutes an example of a plasma generating portion.

[0064] The second high-frequency power supply 64 is a power supply that generates a second high-frequency electric power. The second high-frequency power supply 64 is configured to be able to supply high frequency to the internal space 10s. The second high-frequency electric power has a frequency lower than that of the first high-frequency electric power. When the second high-frequency electric power is used together with the first high-frequency electric power, the second high-frequency electric power is used as a high-frequency electric power for biasing ions to the wafer W. The frequency of the second high-frequency electric power is, for example, a frequency in the range of 400 [kHz] to 13.56 [MHz]. The second high-frequency power supply 64 is connected to the lower electrode 18 via a matcher 68 and an electrode plate 16. The matcher 68 has a circuit that matches the output impedance of the second high-frequency power supply 64 with the impedance of the load side (lower electrode 18 side).

[0065] Alternatively, the plasma may be generated using a second high-frequency power source instead of the first high-frequency power source. In this case, the second high-frequency power source may have a frequency greater than 13.56 MHz, such as 40 MHz. The plasma processing apparatus 1 may also be provided without the first high-frequency power source 62 and the matching unit 66. The second high-frequency power source 64 constitutes an exemplary plasma generating unit.

[0066] In plasma processing apparatus 1, gas is supplied from a gas supply unit into internal space 10s to generate plasma. Furthermore, by supplying first and / or second high-frequency electric power, a high-frequency electric field can be generated between upper electrode 30 and lower electrode 18. This generated high-frequency electric field generates plasma.

[0067] The plasma processing apparatus 1 may further include a control unit 80. The control unit 80 may be a computer having a processor, a storage unit such as a memory, an input device, a display device, a signal input / output interface, and the like. The control unit 80 controls various components of the plasma processing apparatus 1. The control unit 80 is configured to control the first high-frequency power supply 62 and the like (the first high-frequency power supply 62 and the second high-frequency power supply 64) and the gas source assembly 40.

[0068] The control unit 80 allows an operator to manage the plasma processing apparatus 1 by inputting commands using an input device. Furthermore, the control unit 80 can visually display the operating status of the plasma processing apparatus 1 on a display device. Furthermore, the storage unit stores control programs and recipe data. To perform various processes in the plasma processing apparatus 1, the processor executes the control program. The processor executes the control program and controls various components of the plasma processing apparatus 1 according to the recipe data.

[0069] The control unit 80 is configured to control each component of the plasma processing apparatus 1 (specifically, the gas source group 40, the first high frequency power supply 62, etc.) to execute Figure 1 The control unit 80 is configured to control the first high frequency power supply 62 and the gas source set 40 to execute the following processes A and B, in particular, when the substrate W is stored in the internal space 10s.

[0070] That is, the control unit 80 supplies the first gas into the internal space 10s to form the precursor layer PC on the substrate W (process A). After the precursor layer PC is formed, the control unit 80 supplies the second gas into the internal space 10s and supplies energy to at least one of the precursor layer PC and the second gas, thereby forming the organic film OF (organic film OFa) on the substrate W (process B).

[0071] Refer again Figure 1Method MT will now be described. Hereinafter, a case where method MT is performed using plasma processing apparatus 1 will be described as an example. Method MT includes step ST1, step ST2, and step ST1. Step ST1 includes step ST11 and step ST12. Step ST1 may include step STPa and step STB. Furthermore, method MT may include at least one of step STa, step STb, step STc, and step STd.

[0072] In the following description, refer to Figure 1 and Figure 3 . Figure 3 The cross section CS11 shown is an example of a cross section showing, on an enlarged scale, a portion of the substrate W to which the method MT is applied. Figure 3 The cross section CS12 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST1 is performed. Figure 3 The cross section CS13 shown is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in a state after step ST2 is performed.

[0073] A substrate W in cross section CS11 is provided to the interior space 10s before step ST11 is performed. As shown in cross section CS11, substrate W includes a base region UR, a region ER, and a region PR. Region ER is an etched region etched during method MT and is formed, for example, in a layered manner. Region ER is formed on base region UR. Region PR is formed on region ER. As described above, substrate W includes region ER and a patterned region PR disposed on region ER.

[0074] The surface of the substrate W in the cross section CS11 is pre-patterned to provide a plurality of openings OP. The plurality of openings OP may have a certain aspect ratio or may have a plurality of aspect ratios different from each other.

[0075] The region ER includes a silicon-containing film. The material of the region ER is, for example, a silicon-containing material. The material of the region PR can be, for example, an organic material, a silicon-containing material, or a metal-containing material (e.g., a titanium-containing material or a tungsten-containing material). When the material of the region PR is a silicon-containing material, the material of the region ER can be another silicon-containing material. For example, when the material of the region PR is silicon nitride, the material of the region ER can be silicon oxide.

[0076] After the substrate W having the cross section CS11 is provided in the internal space 10s, step ST1 is performed with the substrate W disposed in the internal space 10s. In step ST1, an organic film OF (organic film OFa) is formed on the substrate W. The substrate W is placed on the electrostatic chuck 20 in the internal space 10s.

[0077] Through step ST1, the organic film OF is formed in the opening OP. More specifically, in step ST1, as shown in cross section CS12, the organic film OF is formed on the surface of the substrate W. As described above, in step ST1, the organic film OF is formed on the side of the patterned region PR.

[0078] In step ST11, a first gas GS containing an organic compound is supplied to the inner space 10s to form a precursor layer PC on the substrate W. In step ST11, the first gas GS is supplied to the substrate W. In step ST11, the first gas GS is supplied to the inner space 10s from the gas source group 40. The first gas GS contains an organic compound.

[0079] By executing step ST11, the organic compound of the first gas GS is adsorbed onto the substrate W or the already formed organic film. As a result, a precursor layer PC containing the organic compound of the first gas GS is formed on the substrate W. Step STPa is executed between steps ST11 and ST12. In step STPa, the internal space 10s is purged. In other words, the gas within the internal space 10s is exhausted.

[0080] In step STPa, an inert gas such as a rare gas or nitrogen gas may be supplied to the processing space from the gas source group 40. By executing step STPa, the organic compound of the first gas GS excessively deposited on the substrate W is removed.

[0081] In step ST12, a second gas is supplied into the internal space 10s, supplying energy to at least one of the precursor layer PC and the second gas to modify the precursor layer PC, thereby forming an organic film OF (organic film OFa) on the substrate W. The second gas contains a modified gas. As described above, the energy supplied to at least one of the precursor layer PC and the second gas can be high frequency, microwaves, heat, or the like.

[0082] For example, in step ST12, plasma of the second gas is generated in the internal space 10s so that the precursor layer PC and the plasma of the second gas ( Figure 7 The active species AS) shown in FIG. 4 reacts, thereby forming an organic film on the substrate W.

[0083] In step ST12, plasma of the second gas is generated. In one embodiment, in step ST12, the second gas is supplied to the internal space 10s from the gas source group 40. The second gas can be appropriately selected according to the organic compound of the first gas GS.

[0084] In step ST12, the second gas is excited in the internal space 10s to generate second gas plasma. In step ST12, active species AS such as ions and radicals contained in the second gas plasma react with the organic compound precursor layer PC formed on the substrate W and containing the first gas GS.

[0085] After executing step ST12, step STPb is executed. In step STPb, the internal space 10s is purged. That is, the gas in the internal space 10s is exhausted. In step STPb, an inert gas such as a rare gas or nitrogen (N2 gas) may be supplied to the internal space 10s from the gas source group 40.

[0086] By performing step STPb, the precursor layer PC on the substrate W that has not reacted with the active species AS is removed.

[0087] In step ST1, step ST11 and step ST12 can be repeated alternately through step STJ. For example, a series of steps including step ST11 and step ST12 is performed a predetermined number of times. The predetermined number of times determines the film thickness of the organic film OF.

[0088] In step STJ, it is determined whether a stop condition is satisfied. For example, when the number of executions of a series of steps reaches a predetermined number of times, it is determined that the stop condition is satisfied.

[0089] If it is determined in step STJ that the stop condition is not satisfied, the series of steps are executed again. On the other hand, if it is determined in step STJ that the stop condition is satisfied, step ST1 ends.

[0090] The predetermined number of times of a series of steps in step ST1 may be one. In addition, each series of steps in step ST1 may not include at least one of step STPa and step STPb.

[0091] By performing step ST1, as shown in cross section CS12, an organic film OF is formed on the surface of the substrate W. The width of the opening OP in the region PR can be adjusted by the thickness of the organic film OF.

[0092] In method MT, step ST2 is then performed. Step ST2 is performed with substrate W positioned within internal space 10s. In step ST2, plasma etching of region ER is performed. In step ST2, after the organic film OF has been formed through steps ST1 and STJ, region ER is etched using plasma of a process gas.

[0093] In step ST2, a process gas is supplied to the internal space 10s. When the material of the region ER is silicon oxide, the process gas includes a fluorocarbon gas (eg, C4F6 gas), and may further include a rare gas and oxygen (O2 gas).

[0094] The process gas may include at least one of a hydrofluorocarbon gas, a NF-based gas, or a HF-based gas in addition to or instead of the fluorocarbon gas.

[0095] In step ST2, the exhaust device 50 is controlled to set the pressure in the internal space 10s to a specified pressure. In step ST2, a first high frequency is supplied to excite the process gas. In step ST2, a second high frequency may be supplied together with the first high frequency.

[0096] In step ST2, the process gas is excited in the internal space 10s, generating a process gas plasma. In step ST2, active species such as ions and radicals contained in the process gas plasma are used to etch the region ER. As a result, as shown in cross section CS13, the region ER is removed in the portion exposed in the region including the region PR and the organic film OF.

[0097] Method MT may further include a step STb (breakthrough step) of removing the organic film OF formed on the region ER before step ST2. Step STb is performed between steps ST1 and ST2. In step STb, the organic film OF extending over the portion to be etched in the region ER is removed.

[0098] In step STb, a process gas containing, for example, nitrogen gas (N 2 gas) and hydrogen gas (H 2 gas) is supplied to the internal space 10 s .

[0099] In step STb, the exhaust device 50 is controlled to set the pressure in the internal space 10s to a predetermined pressure. In step STb, a first high frequency is supplied to excite the process gas. In step STb, a second high frequency may be supplied together with the first high frequency.

[0100] By performing step STb, the organic film OF extending over the portion to be etched in the region ER is removed, and the region ER is exposed.

[0101] In steps ST1 and ST2 of the method MT described above, an organic film is formed on the surface of the substrate W by the reaction of the organic compound of the first gas GS with the modified gas of the second gas. By performing the series of steps ST1, including step ST11, step STPa, step ST12, and step STPb, a conformal organic film OF having a suitable film thickness can be formed, similar to film formation by atomic layer deposition.

[0102] Reference Figure 4 and Figure 5 , exemplifying the organic compound constituting the organic film OF, which is produced by the reaction of the organic compound of the first gas GS with the reformed gas of the second gas.

[0103] The first gas GS contains at least one organic compound selected from the group consisting of epoxides, carboxylic acids, carboxylic acid halides, carboxylic anhydrides, isocyanates, and phenols.

[0104] The second gas includes at least one modified gas selected from the group consisting of an inorganic compound gas having an N-H bond, an inert gas, a mixed gas of N2 and H2, H2O gas, and a mixed gas of H2 and O2. For example, the inorganic compound gas having an N-H bond can be at least one selected from the group consisting of N2H2, N2H4, and NH3. The inert gas can be a rare gas such as Ar, N2 gas, or the like.

[0105] When the first gas GS contains at least one selected from the group consisting of carboxylic acid, carboxylic acid halide, and isocyanate, the second gas contains at least one selected from the group consisting of inorganic compound gas having an NH bond, inert gas, a mixed gas of N2 and H2, H2O gas, and a mixed gas of H2 and O2.

[0106] When the first gas GS contains at least one selected from the group consisting of epoxides, carboxylic anhydrides, and phenols, the second gas contains at least one selected from the group consisting of inorganic compound gases having NH bonds, inert gases, and mixed gases of N 2 and H 2 .

[0107] The organic compound of the first gas GS can be, for example, Figure 4 The carboxylic acid or carboxylic acid halide of the chemical formula CF21 or the chemical formula CF22, etc. The organic compound of the first gas GS can be a monofunctional carboxylic acid or a difunctional carboxylic acid.

[0108] When the organic compound is a carboxylic acid or carboxylic acid halide of the chemical formula CF21 or CF22, for example, the reforming gas for the second gas that can be used may be any of the following gases: an inorganic compound gas having an NH bond, an inert gas, a mixed gas of N2 and H2, H2O gas, or a mixed gas of H2 and O2.

[0109] In the chemical formulas CF21 and CF22, R represents a saturated hydrocarbon group such as an alkyl group (linear or cyclic), an unsaturated hydrocarbon group such as an aryl group, or a group containing heteroatoms such as N, O, S, F, or Si. Groups containing heteroatoms include saturated or unsaturated hydrocarbon groups in which a portion of the elements are replaced by N, O, S, F, or Si. In the chemical formulas CF21 and CF22, X may be H or a halogen atom. Examples of carboxylic acids as organic compounds of the first gas GS include terephthalic acid.

[0110] The organic compound that can be generated by the reaction of a carboxylic acid or carboxylic acid halide of the chemical formula CF21 or CF22 with a plasma of any gas such as an inorganic compound gas having an NH bond, an inert gas, or a mixed gas of N2 and H2 may be a polymeric compound having an amide bond. Such a polymeric compound having an amide bond may be, for example, Figure 4 Compounds (polyamides, etc.) represented by the chemical formula CF23, etc. In the chemical formula CF23, n is an integer greater than or equal to 2.

[0111] The organic compound that can be generated by the reaction of a carboxylic acid or carboxylic acid halide of the chemical formula CF21 or CF22 with a plasma of any gas such as H2O gas or a mixed gas of H2 and O2 may be a polymeric compound having an ester bond. Such a polymeric compound having an ester bond may be, for example, Figure 4 Compounds (polyesters, etc.) of the chemical formula CF24, etc. In the chemical formula CF24, n is an integer of 2 or greater.

[0112] In addition, the organic compound of the first gas GS may be, for example, Figure 4 The isocyanate of the chemical formula CF11 or CF12 shown in FIG. The organic compound of the first gas GS may be a monofunctional isocyanate or a difunctional isocyanate.

[0113] When the organic compound is an isocyanate such as chemical formula CF11 or chemical formula CF12, a modified gas of the second gas can be used, which can be any of an inorganic compound gas having an NH bond, an inert gas, a mixed gas of N2 and H2, H2O gas, and a mixed gas of H2 and O2.

[0114] In chemical formulas CF11 and CF12, R is a saturated hydrocarbon group such as an alkyl group (straight-chain or cyclic), an unsaturated hydrocarbon group such as an aryl group, or a group containing heteroatoms such as N, O, S, F, or Si. Groups containing heteroatoms include saturated or unsaturated hydrocarbon groups in which a portion of the elements are replaced by N, O, S, F, or Si. The isocyanate as the organic compound of the first gas GS can be, for example, an aliphatic compound or an aromatic compound. The aliphatic compound can be an aliphatic chain compound or an aliphatic cyclic compound. An example of an aliphatic compound is hexamethylene diisocyanate. Furthermore, an example of an aliphatic cyclic compound is 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI).

[0115] The organic compound that can be generated by the plasma reaction of an isocyanate such as the chemical formula CF11 or the chemical formula CF12 with any gas such as an inorganic compound gas having an NH bond, an inert gas, or a mixed gas of N2 and H2 may be a polymeric compound having a urea bond. Such a polymeric compound having a urea bond is, for example, Figure 3 The compounds represented by the chemical formula CF13 and the like can be produced by a reaction similar to plasma polymerization. In the chemical formula CF13, n is an integer greater than or equal to 2.

[0116] The organic compound that can be generated by the plasma reaction of an isocyanate such as that of the chemical formula CF11 or the chemical formula CF12 with any gas such as H2O gas or a mixed gas of H2 and O2 may be a polymeric compound having a carbamate bond. Such a polymeric compound having a carbamate bond is, for example, Figure 4 Compounds (polyurethane, etc.) represented by the chemical formula CF14 can be produced by a reaction similar to plasma polymerization. In the chemical formula CF14, n is an integer greater than or equal to 2.

[0117] In addition, the organic compound of the first gas GS may be, for example, Figure 5 Carboxylic acid anhydride of the chemical formula CF31 or chemical formula CF32, etc.

[0118] When the organic compound is a carboxylic anhydride such as chemical formula CF31 or chemical formula CF32, the modified gas that can be used as the second gas may be any of an inorganic compound gas having an NH bond, an inert gas, and a mixed gas of N2 and H2.

[0119] In the chemical formulas CF31 and CF32, R represents a saturated hydrocarbon group such as an alkyl group (straight-chain or cyclic), an unsaturated hydrocarbon group such as an aryl group, or a group containing a heteroatom such as N, O, S, F, or Si. Groups containing heteroatoms include saturated or unsaturated hydrocarbon groups in which a portion of the elements are replaced by N, O, S, F, or Si. Examples of carboxylic anhydrides that are organic compounds of the first gas GS include pyromellitic anhydride.

[0120] The organic compound that can be generated by the plasma reaction of a carboxylic acid anhydride of the chemical formula CF31 or CF32 with any gas such as an inorganic compound gas having an NH bond, an inert gas, or a mixed gas of N2 and H2 may be a polymer compound having an imide bond. Such a polymer compound having an imide bond may be, for example, Figure 5 The compound of the chemical formula CF33 shown in FIG. In the chemical formula CF33, n is an integer greater than 2.

[0121] In addition, the organic compound of the first gas GS may be, for example, Figure 5 Epoxides of the chemical formula CF41 shown. When the organic compound is an epoxide of the chemical formula CF41, a modified gas of the second gas can be used, which may be any gas including an inorganic compound gas having an NH bond, an inert gas, or a mixed gas of N2 and H2.

[0122] In the chemical formula CF41, R is a saturated hydrocarbon group such as an alkyl group (straight-chain alkyl group or cyclic alkyl group), an unsaturated hydrocarbon group such as an aryl group, or a group containing a heteroatom such as N, O, S, F, or Si. Groups containing heteroatoms include saturated hydrocarbon groups or unsaturated hydrocarbon groups in which a portion of the elements are replaced by N, O, S, F, Si, or the like.

[0123] An organic compound that can be generated by a plasma reaction of an epoxide such as CF41 with an inorganic compound gas having an NH bond, an inert gas, or a mixed gas of N2 and H2 may be an epoxy resin. Such an epoxy resin may be, for example, Figure 5 A polymer compound of the chemical formula CF42 shown in FIG. In the chemical formula CF42, n is an integer greater than or equal to 2.

[0124] In addition to the above, phenols can be used as organic compounds in the first gas GS. Examples of phenols include phenol, cresol, and hydroquinone. In this case, the reforming gas serving as the second gas can be at least one selected from the group consisting of inorganic compound gases having N-H bonds, inert gases, and mixed gases of N₂ and H₂.

[0125] In the following description, refer to Figure 1 and Figure 6 . Figure 6 Cross section CS21 is an example of a cross section showing an enlarged portion of a substrate W to which method MT can be applied. Figure 6 The cross section CS22 is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in a state after step STa is performed.

[0126] Figure 6 The cross section CS23 is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in a state after step ST1 is performed. Figure 6 The cross section CS24 is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in a state after step STb is performed. Figure 6 The cross section CS25 is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in the state after step ST2 is performed.

[0127] In one embodiment, method MT may be applied to substrate W in cross section CS21. In this case, method MT is performed using plasma processing apparatus 1. Method MT is performed with substrate W disposed in internal space 10s.

[0128] The substrate W in cross section CS21 includes a base region UR, a region ER, and a patterned layer PL. The region ER is formed on the base region UR. The region ER is, for example, a silicon film. The layer PL is formed on the region ER. The material of the layer PL can be, for example, silicon oxide.

[0129] The surface of the substrate W in cross section CS21 is pre-patterned to provide a plurality of openings OP. More specifically, the layer PL shown in cross section CS21 is pre-patterned. The layer PL is patterned to provide openings OP. The plurality of openings OP may have a certain aspect ratio or may have a plurality of different aspect ratios.

[0130] Method MT applied to the substrate W of section CS21 further includes step STa. Step STa is performed after the step of providing the substrate W into the internal space 10s of the chamber 10. Step STa is performed after providing the substrate W of section CS21 into the internal space 10s and before step ST1.

[0131] In step STa, plasma etching is performed on the region ER. In step STa, the region ER is partially etched to form the recessed portion CO. Specifically, the region ER is etched to a position between the surface (the surface on the layer PL side) and the bottom surface (the surface on the base region UR side) in the film thickness direction of the region ER.

[0132] In the method MT applied to the substrate W in the cross section CS21 , in step STa, a process gas is supplied to the internal space 10 s .

[0133] The process gas is a halogen-containing gas, such as HBr gas. The process gas may further contain Cl2 gas in addition to or instead of HBr gas.

[0134] In step STa, the exhaust device 50 is controlled to set the pressure in the internal space 10s to a predetermined pressure. In step STa, a first high frequency is supplied to excite the process gas. In step STa, a second high frequency may be supplied together with the first high frequency.

[0135] In step STa, active species such as ions and radicals contained in the plasma of the process gas are used to etch region ER, thereby forming a recessed portion CO (see cross section CS22). As described above, method MT includes step STa, which, prior to step ST1, supplies process gas into internal space 10s to partially etch region ER of substrate W through the patterned region (layer PL) of substrate W to form recessed portion CO. The surface of region ER defining recessed portion CO includes a bottom surface ERB and side surfaces ERS.

[0136] In method MT applied to substrate W in cross section CS21, step ST1 is then performed. By step ST1, an organic film OF is formed within recess CO. More specifically, by performing step ST1, as shown in cross section CS23, an organic film OF is formed on the surface of layer PL and the surface of recess CO.

[0137] In method MT applied to substrate W in cross section CS21, step STb can be performed after step ST1. By performing step STb, the organic film OF extending over bottom surface ERB is removed (see cross section CS24). In step STb, the organic film OF extending over bottom surface ERB is removed using plasma of the process gas.

[0138] In the method MT applied to the substrate W in the cross section CS21, step ST2 is then performed. In step ST2, plasma of the processing gas is generated in the same manner as in step STa. As a result, as shown in the cross section CS25, the recess CO is further etched.

[0139] During step ST2 , the organic film OF extending on the side surface ERS can suppress lateral etching of the portion ERP of the region ER. That is, lateral etching of the recessed portion CO can be suppressed.

[0140] Method MT applied to substrate W in section CS21 may further include step STc. In step STc, the organic film OF may be removed. The organic film OF may be removed by plasma of a process gas generated within internal space 10s. The process gas may include, for example, N2 gas and H2 gas.

[0141] The organic film OF can also be removed by heating the substrate W. Such an organic film OF can be an organic compound contained in the first gas GS such as an isocyanate (e.g. Figure 3 In the case of an organic compound (e.g., an organic compound of the chemical formula CF11 or chemical formula CF12) Figure 3 The temperature of substrate W used to remove the organic film OF can be between 250°C and 400°C. When substrate W is heated in this manner, the organic compound constituting the organic film OF depolymerizes. The gas generated by the depolymerization is exhausted. Alternatively, substrate W can be heated by one or more heaters within electrostatic chuck 20.

[0142] Alternatively, in step ST1, a sub-conformal organic film OF may be formed on the surface of the layer PL and at least a portion of the side surfaces of the recess CO. Here, a sub-conformal organic film refers to an organic film OF having varying thicknesses along the thickness direction of the substrate. In this case, no organic film OF is formed on the bottom surface of the recess CO, and therefore step STb is unnecessary.

[0143] The subconformal organic film OF can be formed by not forming the precursor layer PC on the entire surface of the concave portion CO in step ST11 and / or not modifying the precursor layer PC on the entire surface of the concave portion CO in step ST12. Figure 7 , a detailed description will be given of the case where the precursor layer PC is not modified on the entire surface of the concave portion CO.

[0144] Figure 7 The cross section CS12a shown is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in a state after step ST11 is performed. Figure 7 The cross section CS12b shown is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in the state in which step ST12 is being performed. Figure 7 The cross section CS12c shown is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in a state after step ST12 is performed. Figure 7 The cross section CS12d shown is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in a state after step STPb is performed.

[0145] exist Figure 7 In the example shown, the range of the organic film OF formation within the opening OP can be adjusted by adjusting the execution timing of step ST12, that is, the supply timing of the active species AS contained in the second gas plasma. Adjusting the execution timing of step ST12 can also appropriately adjust the range of the precursor layer PC that reacts with the active species AS contained in the plasma.

[0146] If step ST12 is executed for a sufficiently long time, the active species AS can react with the entire precursor layer PC preformed within the opening OP in step ST11. In this case, the entire side surface within the opening OP is covered with the organic film OFa. To address this issue, the execution time of step ST12 can be adjusted so that the active species AS reacts only with a portion of the precursor layer PC preformed within the opening OP in step ST11. By repeatedly executing step ST1, including step ST12 with this execution time, the extent of the organic film OFa formed within the opening OP can be appropriately adjusted.

[0147] In the following description, refer to Figure 1 and Figure 8 . Figure 8 Cross section CS31 is an example of a cross section showing an enlarged portion of a substrate W to which method MTA can be applied. Figure 8 The cross section CS32 is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST1 is performed. Figure 8 The cross section CS33 is an example of a cross section showing, on an enlarged scale, a portion of the substrate W in the state after step STb is performed.

[0148] Figure 8 The cross section CS34 is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST21 is performed. Figure 8 The cross section CS35 is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST1 is performed. Figure 8 Cross section CS36 is an example of a cross section showing an enlarged portion of the substrate W in the state after step STd is performed.

[0149] In one embodiment, method MT may be applied to a substrate W shown in cross section CS31. In this case, method MT is performed using plasma processing apparatus 1. Method MT is performed with substrate W disposed in internal space 10s.

[0150] The substrate W shown in the cross section CS31 includes a region PR, a region ER, and a mask MK. The region ER is surrounded by the side surfaces of the region PR or sandwiched between a pair of side surfaces of the region PR. The region ER is a region to be etched by performing the method MT.

[0151] The mask MK is provided on top of the region PR. The material of the mask MK is a material resistant to etching of the region ER, such as an organic material or a metal-containing material. Examples of the metal-containing material include a titanium-containing material and a tungsten-containing material.

[0152] An opening GV (e.g., a groove) may be formed between region ER and region PR. The surface of substrate W in cross section CS31 is pre-patterned to provide a plurality of openings GV. More specifically, region PR shown in cross section CS31 is pre-patterned. Region PR is pre-patterned to provide openings GV. The plurality of openings GV may have a certain aspect ratio or may have a plurality of different aspect ratios.

[0153] The materials of the regions ER and PR can be the same. In this case, the regions ER and PR are formed by etching a single film. The materials of the regions PR and ER can be, for example, a low-dielectric-constant material or a porous layer. The low-dielectric-constant material contains, for example, silicon, oxygen, carbon, and hydrogen. More specifically, the materials of the regions PR and ER can be, for example, a silicon-containing material.

[0154] In method MT applied to substrate W in section CS31, step ST1 may be performed on substrate W in section CS31 after substrate W in section CS31 is provided to internal space 10s. A series of steps including steps ST11 and ST12 is performed once or more through step STJ.

[0155] By executing step ST1, as shown in cross section CS32, an organic film OF is formed on the surface of the mask MK, the surface of the region PR, and the surface of the region ER. The organic film OF covers the surface of the substrate W, namely, the surface of the mask MK, the surface of the region PR, and the surface of the region ER. In particular, the organic film OF is formed within the opening GV. More specifically, the opening GV is filled with the organic film OF.

[0156] In method MT applied to substrate W in cross section CS31, step STb is then performed. By performing step STb, as shown in cross section CS33, the organic film OF extending on the upper surface of region ER is etched, leaving the organic film OF along the side surface (or a pair of side surfaces) of region PR, i.e., within opening GV.

[0157] By performing step STb, the by-product BP1 is deposited on the organic film OF as shown in the cross section CS33. The by-product BP1 contains carbon. The by-product BP1 may also contain nitrogen.

[0158] In method MT applied to substrate W in section CS31, step ST2 is then performed. In step ST2, as shown in section CS34, plasma etching of region ER is performed. In step ST2, a process gas is supplied to internal space 10s.

[0159] The process gas includes a fluorocarbon gas (e.g., C4F8 gas). The process gas may also include a rare gas, nitrogen (N2 gas), and oxygen (O2 gas). In addition to or in place of the fluorocarbon gas, the process gas may also include at least one of a hydrofluorocarbon gas, a NF-type gas, or a HF-type gas.

[0160] In step ST2, the exhaust device 50 is controlled to set the pressure in the internal space 10s to a predetermined pressure. In step ST2, a first high frequency is supplied to excite the process gas. In step ST2, a second high frequency may be supplied together with the first high frequency.

[0161] In step ST2, the region ER is etched using active species such as ions and radicals contained in the plasma of the processing gas. In this case, the plasma etching in step ST2 may be the same as the plasma etching for forming the opening GV.

[0162] In addition, the processing gas used in step ST2 can be selected according to the material constituting the region ER.

[0163] By executing step ST2, byproduct BP2 is deposited on byproduct BP1 and on organic film OF as shown in cross section CS34. Byproduct BP2 contains chemical species in the plasma generated in step ST2 and constituent materials of region ER (eg, silicon).

[0164] In the method MT applied to the substrate W of the cross section CS31, step STc is then performed. In step STc, as shown in the cross section CS35, the organic film OF is removed.

[0165] The organic film OF is removed by heating the substrate W. As a result of depolymerization caused by heating, the organic film OF can be removed. Such an organic film OF may include an organic compound such as an isocyanate (e.g. Figure 4 In the case of an organic compound (e.g., an organic compound of the chemical formula CF11 or chemical formula CF12) Figure 4 The temperature of substrate W used to remove the organic film OF is set to between 250°C and 400°C. Heating substrate W as described above depolymerizes the organic compound constituting the organic film OF. The gas generated by the depolymerization is exhausted. Alternatively, substrate W may be heated by one or more heaters within electrostatic chuck 20.

[0166] In the method MT applied to the substrate W of the cross section CS31, after the step STc is performed, a residue RS is formed as shown in the cross section CS35. The residue RS contains the by-product BP1 and / or the by-product BP2.

[0167] In order to remove the residue RS, step STd is performed. In step STd, plasma etching is performed in the same manner as step ST2. As a result of the plasma etching in step STd, the residue RS is removed as shown in cross section CS36.

[0168] Figure 9 The flowchart shown shows another exemplary embodiment of a substrate processing method (hereinafter referred to as method MT1). Method MT1 includes step ST110, step ST120 (first step), step ST130 (second step), and step ST140. Method MT1 can be performed using, for example, Figure 2 The method MT1 is performed by the plasma processing apparatus 1 shown. In this case, the method MT1 can be performed by the control unit 80 of the plasma processing apparatus 1.

[0169] First, in step ST110, a substrate having a mask with an opening having a high aspect ratio is provided to the interior space of a chamber. In the present invention, a "high aspect ratio opening" refers to an opening having a ratio of the depth of the mask to the opening size of 5 or more.

[0170] In step ST120 following step ST110, a first film is formed on the side of the mask. The first film may be, for example, an organic film. The organic film has different thicknesses along the thickness direction of the substrate. In step ST120, Figure 1 The series of steps including step ST1 and step STJ shown in the figure is the same process. However, the organic film in method MT1 is formed by not forming the precursor layer PC on the entire surface of the concave portion CO in step ST11 and / or not modifying the precursor layer PC on the entire surface of the concave portion CO in step ST12.

[0171] In step ST130 following step ST120, the first film is trimmed. In the present invention, trimming can be performed by, for example, Figure 1 The same etching process is performed as in step ST2 shown.

[0172] In step ST140 following step ST130 , it is determined whether the opening size after trimming has reached a preset value. In the present invention, the opening size may be, for example, a critical dimension (CD).

[0173] If it is determined in step ST140 that the opening size after trimming has reached the preset value (step ST140: Yes), the process ends. If it is determined in step ST140 that the opening size after trimming has not reached the preset value (step ST140: No), the processes of steps ST120 to ST140 are repeated. As described above, the loop including steps ST120 and ST130 is executed one or more times.

[0174] Next, refer to Figure 9 and Figure 10 , further illustrating method MT1. Figure 10 In the figure, the X direction corresponds to the thickness direction of the substrate, and the Y direction corresponds to the width direction of the surface of the substrate.

[0175] Figure 10 The cross section CS41 shown is an example of a cross section showing, on an enlarged scale, a portion of the substrate W provided in step ST110 to which the method MT1 can be applied. Figure 10 The cross section CS42 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST120 is performed.

[0176] Figure 10 The cross section CS43 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST130 is performed. Figure 10 The cross section CS44 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner when the answer to step ST140 is "Yes".

[0177] As shown in cross section CS41, substrate W includes an etching film 110 (etching region) and a patterned mask 120 (region) formed on etching film 110. Mask 120 includes an opening 200. Opening 200 includes a top 200T, sidewalls 200S, and a bottom 200B.

[0178] The sidewall 200S of the opening 200 has an abnormal shape portion 200X. The opening 200 has a high aspect ratio. For example, the aspect ratio of the opening 200 is 5 or more or 10 or more.

[0179] First, in step ST110 , a cross section CS41 is provided. In step ST120 following step ST110 , as shown in cross section CS42 , a first film 130 is formed on the inner peripheral surface of the opening 200 (eg, at least a portion of the sidewall 200S including the shape abnormality 200X).

[0180] The first film 130 is formed along the stacking direction ( Figure 10 In other words, the thickness of the first film 130 is subconformal along the stacking direction of the mask 120. For example, Figure 10 In the case of the cross section CS42 shown, the first film 130 has a film thickness that varies depending on the distance from the top 200T of the mask 120 , and the film thickness of the first film 130 gradually decreases toward the bottom 200B.

[0181] The first film 130 is mainly formed on the shape abnormality portion 200X. The first film 130 covers the shape abnormality portion 200X. The opening size of the opening 200 can be reduced at the position of the shape abnormality portion 200X according to the film thickness of the first film 130.

[0182] The first film 130 having the above-described shape can be formed using, for example, chemical vapor deposition (CVD) or atomic layer deposition (ALD). Note that the film forming method used in step ST120 is not limited to the above-described method.

[0183] In step ST130 following step ST120, first film 130 is trimmed. The trimming removes the surface of first film 130, making it smooth along the stacking direction as shown in cross section CS43. In cross section CS43, compared to cross section CS41, the formation of first film 130 on shape abnormality 200X mitigates shape abnormality 200X.

[0184] As described above, the differences between the opening size at the top 200T, the opening size at the shape abnormality 200X, and the opening size at the bottom 200B of the opening 200 before step ST120 decrease after step ST130 .

[0185] Furthermore, as described above, in step ST120, the film formation process is performed under processing conditions that decrease the thickness of the first film 130 from the top 200T toward the bottom 200B. Therefore, fluctuations in the opening size of the bottom 200B between before step ST120 and after step ST130 are suppressed. For example, the opening size W1 of the bottom 200B in cross section CS41 is substantially the same as the opening size W2 of the bottom 200B in cross section CS43.

[0186] Therefore, by executing Figure 9 The illustrated process can correct shape abnormalities such as conformality or necking that may occur at a predetermined position in the stacking direction without changing the opening size of the bottom portion 200B of the opening 200 .

[0187] In step ST140 following step ST120, it is determined whether the opening size of the opening 200 has reached a predetermined value. "The opening size has reached a predetermined value" means, for example, that the opening size of the top 200T of the opening 200, the opening size at a predetermined position (e.g., the shape anomaly 200X) of the side wall 200S, and the difference between the opening size of the bottom 200B are within a predetermined range.

[0188] The determination in step ST140 is made, for example, based on the number of executions (loops) of steps ST120 and ST130. In step ST140, whether the opening size has reached a predetermined value is determined by determining whether the number of loops of steps ST120 and ST130 has reached a predetermined number. The number of loops of steps ST120 and ST130 to be executed until the opening size reaches the predetermined value is predetermined.

[0189] In step ST140 , when the number of executions of step ST120 and step ST130 reaches a predetermined number of times, it is determined that the opening size has reached a predetermined value (step ST140 : Yes).

[0190] In step ST140 , if the number of executions of steps ST120 and ST130 has not reached the preset number, it is determined that the opening size has not reached the preset value (step ST140 : No). In this case, steps ST120 and ST130 are executed again.

[0191] For example, when the state of the substrate W at the time of determination in step ST140 is the state shown in cross section CS44, it is determined that the opening size has reached a preset value, and the processing is terminated.

[0192] Furthermore, the material of the first film 130 can be the same material as that of the mask 120. The mask 120 can be, for example, a carbon-containing film, a silicon-containing film, or a metal film. By making the first film 130 and the mask 120 of the same material, control can be facilitated during processing after method MT1. For example, during etching, the etching rates of the first film 130 and the mask 120 can be made consistent.

[0193] Therefore, when etching is performed after forming the first film 130, the size of the bottom 200B of the opening 200 can be easily controlled. Furthermore, by making the first film 130 and the mask 120 of the same type of film, the amount removed by etching can be easily controlled.

[0194] In this regard, for example, when the mask 120 is a carbon-containing film, the etching film 110 may be a silicon-containing film, a metal film, or the like.

[0195] The carbon-containing film may be, for example, an amorphous carbon layer (ALC). The silicon-containing film may be, for example, a silicon oxide film (SiO), a silicon nitride film (SiN), a silicon oxynitride film (SiON), or a combination thereof. The metal film may be, for example, a titanium (Ti) film, a tungsten (W) film, or the like.

[0196] Furthermore, for example, when the mask 120 is a silicon-containing film, the etching film 110 may be a carbon-containing film, a metal film, or a silicon-containing film having a composition different from that of the mask 120. Furthermore, for example, when the mask 120 is a metal film, the etching film 110 may be a silicon-containing film, a carbon-containing film, or the like.

[0197] Alternatively, the etching film 110 may be a laminated film in which a plurality of layers are laminated. For example, the etching film 110 may be an ONON (oxide / nitride) film, an OPOP (oxide / polysilicon) film, or the like.

[0198] Alternatively, steps ST120 and ST130 may be executed multiple times in succession. For example, step ST120 may be executed five times in succession, followed by step ST130 once. For example, step ST120 may be executed 10 to 50 times in succession, followed by step ST130 twice.

[0199] Below, refer to Figure 11 , further illustrating method MT1. In the following description, reference is made to Figure 9 and Figure 11 .exist Figure 11 In the figure, the X direction corresponds to the thickness direction of the substrate, and the Y direction corresponds to the width direction of the surface of the substrate.

[0200] Figure 11 The cross section CS51 shown is an example of a cross section showing, in an enlarged manner, a portion of the substrate W provided in step ST110 to which the method MT1 can be applied. Figure 11 The cross section CS52 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST120 is performed. Figure 11 The cross section CS53 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner when the answer to step ST140 is "Yes".

[0201] As shown in cross section CS51, the substrate W has an etching film 111 (etching region) and a patterned mask 121 (region) formed on the etching film 111. The material of the etching film 111 may be the same kind of material as that of the etching film 110.

[0202] An opening 201 is formed in mask 121. The material of mask 121 can be the same as that of mask 120. Opening 201 tapers from top 201T to bottom 201B in a tapered shape. As shown in cross section CS52, in step ST120, a first film 131 having a thickness varying along the stacking direction of mask 121 is formed on sidewalls 201S of opening 201.

[0203] As described above, in step ST120, the first film 131 is formed on the sidewalls 201S (side surfaces) of the patterned mask 121. The material of the first film 131 may be the same type of material as that of the first film 130.

[0204] Since the shape of the inner peripheral surface (side wall 201S) of the opening 201 can be corrected by the first film 131 , the difference in the opening size in the stacking direction (X direction) can be reduced by the film thickness of the first film 131 .

[0205] In step ST130, following step ST120, the first film 131 is trimmed. By performing steps ST120 and ST130, the tapered shape within the opening 201 is softened. Therefore, as shown in cross section CS53, by repeating steps ST120 and ST130, the difference in opening size between the top 201T, sidewall 201S, and bottom 201B can be reduced compared to the difference in opening size before processing. By repeating the cycle including steps ST120 and ST130, the difference in opening size in the stacking direction (X direction) can be reduced, and the shape of the mask 121 can be corrected.

[0206] Figure 12 The flowchart shown shows another exemplary embodiment of the substrate processing method (hereinafter referred to as method MT2). ​​Method MT2 includes step ST410, step ST420, step ST430 (first step), step ST440 (second step), and step ST450. Method MT2 can be performed using, for example, Figure 2 In this case, the method MT2 can be executed by the control unit 80 of the plasma processing apparatus 1 .

[0207] First, in step ST410, a substrate with a mask is provided in the inner space of a chamber. In step ST420 following step ST410, a preliminary film is formed on the inner peripheral surface of the opening provided in the mask. Figure 10 The first film 130 shown is different and is formed over the entire opening. For example, the preliminary film can be a conformal film.

[0208] In step ST430 following step ST420, a first film is formed on the inner peripheral surface of the opening from the preliminary film. The first film may be, for example, an organic film. That is, in step ST430, an organic film is formed on the substrate. In step ST430, Figure 1 The series of steps including step ST1 and step STJ shown are the same as the process. In method MT2, the first film has a different film thickness along the stacking direction of the mask, similarly to the first film in method MT1.

[0209] In step ST440 following step ST430, the first film is trimmed. In step ST450 following step ST440, it is determined whether the opening dimension (CD) of the trimmed opening has reached a predetermined value. If it is determined in step ST450 that the opening dimension of the trimmed opening has reached the predetermined value (step ST450: Yes), the process ends.

[0210] If it is determined in step ST450 that the opening size after trimming is not the preset value (step ST450: No), the processing of steps ST420 to ST450 is repeated. As described above, the loop including steps ST430 and ST440 is executed one or more times.

[0211] Different from the method MT1, the method MT2 forms two films on the mask and then performs trimming. For example, if you want to suppress the bottom 200B and the bottom 201B (see Figure 10 and Figure 11 ) increases, method MT2 can be applied.

[0212] Next, refer to Figure 13 , further illustrating method MT2. In the following description, reference is made to Figure 12 and Figure 13 .exist Figure 13 In the figure, the X direction corresponds to the thickness direction of the substrate, and the Y direction corresponds to the width direction of the surface of the substrate.

[0213] Figure 13 The cross section CS61 shown is an example of a cross section showing an enlarged portion of the substrate W provided in step ST410 to which the method MT2 can be applied. The shape of the cross section CS61 is similar to Figure 10 The shape of the cross section CS41 shown is the same. Figure 13 The cross section CS62 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST420 is performed.

[0214] Figure 13The cross section CS63 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST430 is performed. Figure 13 The cross section CS64 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST440 is performed. Figure 13 The cross section CS65 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner when the answer to step ST450 is yes.

[0215] First, in step ST410 , a cross section CS61 is provided. In step ST420 following step ST410 , as shown in cross section CS62 , a preliminary film 130 a is formed in the opening 200 .

[0216] The preliminary film 130a is formed on the entire inner surface of the opening 200 (including the sidewall 200S and the bottom 200B). Figure 10 Unlike the first film 130 shown, the thickness may not vary along the stacking direction (X direction). That is, for example, the preliminary film 130a may have a uniform thickness from the top 200T to the bottom 200B. The preliminary film 130a may be formed by ALD, for example.

[0217] In step ST430 following step ST420, as shown in cross section CS63, a first film 130b is formed on the preliminary film 130a. Figure 10 The first film 130 shown also has different film thicknesses along the stacking direction of the mask 120. For example, the first film 130b is mainly formed on the shape abnormality portion 200X. The film forming method of the first film 130b is the same as that of the first film 130b. Figure 10 The film forming method of the first film 130 shown is the same.

[0218] The material of the preliminary film 130a is the same as that of the mask 120. The material of the first film 130b is the same as that of the etching film 110. Furthermore, the materials are selected so as to achieve a high selectivity between the materials of the preliminary film 130a and the materials of the first film 130b. This is because the post-formation trimming of the first film 130b (step ST440) is primarily performed under processing conditions that enable removal of the preliminary film 130a.

[0219] By setting the processing conditions as described above, the first film 130b formed on the shape abnormality 200X can be left, while the reserve film 130a formed on portions other than the shape abnormality 200X can be effectively removed. Thus, the shape abnormality 200X can be buried with the reserve film 130a, while variations in the opening dimensions of other portions within the opening 200 can be suppressed.

[0220] In step ST440 following step ST430, as shown in cross section CS64, trimming is performed within opening 200. In the example of cross section CS64, reserve film 130a is removed from the lower portion of sidewall 200S and bottom 200B of opening 200, leaving reserve film 130a and first film 130b from shape anomaly 200X to top 200T. As described above, method MT2 allows for appropriate correction of the mask shape.

[0221] In method MT2, steps ST420, ST430, and ST440 can be repeatedly performed until the opening size of opening 200 reaches a predetermined value. For example, the steps can be repeatedly performed until the difference in opening size between top 200T, sidewall 200S, and bottom 200B of opening 200 reaches a predetermined value.

[0222] Cross section CS65 shows the state of the substrate W when the shape of the mask pattern (opening 200 ) is trimmed and the opening size reaches a predetermined value. The shape of cross section CS65 may also be achieved by further etching after step ST450 .

[0223] Next, refer to Figure 14 Further explanation of method MT2. In the following description, reference is made to Figure 12 and Figure 14 .exist Figure 14 In the figure, the X direction corresponds to the thickness direction of the substrate, and the Y direction corresponds to the width direction of the surface of the substrate.

[0224] Figure 14 The cross section CS71 shown is an example of a cross section showing an enlarged portion of the substrate W provided in step ST410 to which the method MT2 can be applied. The shape of the cross section CS71 is similar to Figure 11 The shape of the cross section CS51 shown is the same. Figure 14 The cross section CS72 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST420 is performed.

[0225] Figure 14 The cross section CS73 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST430 is performed. Figure 14 The cross section CS74 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner after step ST440 is performed. Figure 14 The cross section CS75 shown is an example of a cross section showing a portion of the substrate W in an enlarged manner when the answer to step ST450 is "Yes".

[0226] exist Figure 14 In the example, Figure 13Similarly, as shown in cross section CS72, in step 420, before step ST430, a conformal preliminary film 131a is formed over the entire opening 201. In step ST430 following step ST420, as shown in cross section CS73, a first film 131b having a different film thickness in the stacking direction (X direction) is formed on preliminary film 131a.

[0227] In step ST440 following step ST430, trimming is performed. In this case, as shown in cross section CS74, the reserve film 131a is removed near the bottom 201B, and the remaining reserve film 131a and first film 131b reduce the taper within the opening 201 (the taper shape is relaxed). Therefore, by repeating steps ST420 to ST440, the taper of the opening 201 can be appropriately corrected, as shown in cross section CS75.

[0228] As described above, method MT2 further includes step ST420 of forming a conformal preliminary film at the opening, which is performed before step ST430. Therefore, according to method MT2, the size of the opening of the mask can be adjusted and the shape of the mask can be corrected.

[0229] Furthermore, in method MT2, the materials of the reserve film and the first film may have different etching selectivities. For example, the materials of the reserve film and the first film may be selected so that the amount of the reserve film removed during the trimming step ST440 is greater than that of the first film. This improves the corrective effect of the trimming.

[0230] In method MT2, the material of the preliminary film can be the same as that of the mask, and the material of the first film can be the same as that of the etching film under the mask. Therefore, when etching is performed under etching conditions appropriate to the mask, the first film can remain, and the shape of the mask can be effectively corrected.

[0231] Although various exemplary embodiments have been described above, the present invention is not limited to the exemplary embodiments described above, and various omissions, substitutions, and changes can be made. Furthermore, elements in different exemplary embodiments can be combined to form other exemplary embodiments.

[0232] For example, methods MT, MT1, and MT2 may be performed using a plasma processing apparatus other than plasma processing apparatus 1. Examples of such a plasma processing apparatus include an inductively coupled plasma processing apparatus and a plasma processing apparatus that generates plasma using surface waves such as microwaves.

[0233] Furthermore, the steps of forming the organic film (step ST1, step ST120, step ST420, and step ST430) and etching (step ST12, step ST130, and step ST440) may be performed in the same chamber (in-situ) while maintaining a reduced pressure atmosphere. Alternatively, the steps of forming the organic film (step ST1, step ST120, step ST420, and step ST430) and etching (step ST12, step ST130, and step ST440) may be performed in the same system (in-system).

[0234] Based on the above description, various exemplary embodiments of the present invention have been described in this specification for illustrative purposes. It should be understood that various modifications may be made without departing from the scope and spirit of the present invention. Therefore, the various exemplary embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are set forth in the appended claims.

Claims

1. A substrate processing method, characterized in that: include: a) providing a substrate into a chamber, the substrate having an etched region and a patterned region formed on the etched region, the etched region being surrounded by sides of the patterned region; b) forming an organic film on the surface of the substrate; and c) after b), etching the etched area through the patterned area using plasma of a process gas, b) includes: b1) supplying a first gas containing an organic compound to the substrate to form a precursor layer on the substrate; and b2) supplying a second gas containing a modifying gas to the substrate, supplying energy to at least one of the precursor layer and the second gas to modify the precursor layer to form the organic film, In b2), the organic film is formed by modifying the precursor layer by generating plasma of the second gas.

2. The substrate processing method according to claim 1, wherein: The above b1) and b2) are repeated alternately.

3. The substrate processing method according to claim 1 or 2, wherein: The method further includes the step of d) etching the organic film extending on the etched region before the step c) so as to leave the organic film at a portion along the side surface of the patterned region.

4. The substrate processing method according to claim 1 or 2, wherein: Also includes: e) before step b), using plasma of a processing gas, partially etching the etching area through the patterned area to form a recess; and f) After step b), further etching the recessed portion using plasma of a processing gas.

5. The substrate processing method according to claim 4, wherein: In b1), the precursor layer is not formed on the entire surface of the recessed portion, and / or in b2), the precursor layer is not modified on the entire surface of the recessed portion.

6. The substrate processing method according to claim 4, wherein: The organic film has different thicknesses along a thickness direction of the substrate.

7. The substrate processing method according to claim 1 or 2, wherein: Also includes: g) after b), performing a step of trimming the organic film, In the above b), the organic film is formed to have different thicknesses along the thickness direction of the substrate at the side surface.

8. The substrate processing method according to claim 7, wherein: Also includes: i) before step b), forming a conformal organic film on the entire side surface.

9. The substrate processing method according to claim 1 or 2, wherein: The first gas contains at least one organic compound selected from the group consisting of epoxides, carboxylic acids, carboxylic acid halides, carboxylic anhydrides, isocyanates, and phenols.

10. The substrate processing method according to claim 1 or 2, wherein: The second gas includes at least one modifying gas selected from the group consisting of an inorganic compound gas having an NH bond, an inert gas, a mixed gas of N 2 and H 2 , an H 2 O gas, and a mixed gas of H 2 and O 2 .

11. The substrate processing method according to claim 1 or 2, wherein: In the case where the first gas contains at least one organic compound selected from the group of carboxylic acids, carboxylic acid halides and isocyanates, the second gas contains at least one modified gas selected from the group of inorganic compound gases having NH bonds, inert gases, mixed gases of N2 and H2, H2O gas and mixed gases of H2 and O2.

12. The substrate processing method according to claim 1 or 2, wherein: In the case where the first gas contains at least one organic compound selected from the group of epoxides, carboxylic anhydrides and phenols, the second gas contains at least one modified gas selected from the group of inorganic compound gases having NH bonds, inert gases and mixed gases of N2 and H2.

13. The substrate processing method according to claim 10, wherein: The inorganic compound gas having an NH bond is at least one selected from the group consisting of N2H2, N2H4 and NH3.

14. The substrate processing method according to claim 1 or 2, wherein: The etched region includes a silicon-containing film.

15. The substrate processing method according to claim 1 or 2, wherein: The step of forming the organic film and the step of etching are performed in the same chamber (in-situ) or the same system (in-system) while maintaining a reduced pressure atmosphere.

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