Method for processing substrate, device manufacturing method and plasma processing apparatus

Abstract

The present invention discloses a method for processing a substrate, comprising (a) providing a substrate into a chamber of a plasma processing apparatus. The substrate has a patterned organic mask. The method further comprises (b) generating plasma from a processing gas in the chamber while the substrate is contained in the chamber. The method further comprises (c) periodically applying a pulsed negative DC voltage to an upper electrode of the plasma processing apparatus during the plasma generation step (i.e., (b)). During the application of the pulsed negative DC voltage, ions from the plasma are supplied to the upper electrode, and silicon-containing material released from the upper electrode is deposited on the substrate.

Description

Technical Field

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

[0002] In the manufacture of electronic devices, there is a case where a substrate having a patterned organic mask is treated with plasma. Japanese Patent Publication No. 2017-98455, Japanese Patent Publication No. 2014-96499 and Japanese Patent Publication No. 2006-270019 disclose plasma treatment for modifying an organic mask. In the plasma treatment described in these documents, a capacitively coupled plasma treatment device is used. The capacitively coupled plasma treatment device includes a chamber, a substrate support and an upper electrode. The substrate support is arranged in the chamber. The upper electrode is arranged above the substrate support. Plasma is generated by a processing gas in the chamber. Then, a negative DC voltage is applied to the upper electrode. As a result, positive ions from the plasma collide with the upper electrode and release secondary electrons and / or silicon from the upper electrode. The released secondary electrons and / or silicon modify the organic mask. Summary of the Invention

[0003] The present invention provides a technology for suppressing shape variation of an organic mask pattern and shrinkage of the organic mask during plasma processing of the organic mask.

[0004] In one exemplary embodiment, a method for processing a substrate is provided. The method includes (a) providing a substrate having a patterned organic mask into a chamber of a plasma processing apparatus. The method also includes (b) generating a plasma from a processing gas within the chamber while the substrate is contained within the chamber. The method also includes (c) periodically applying a pulsed negative DC voltage to an upper electrode of the plasma processing apparatus during the execution of (b). In (c), ions from the plasma are supplied to the upper electrode, and silicon-containing material released from the upper electrode is deposited onto the substrate.

[0005] According to an exemplary embodiment, in plasma processing of an organic mask, it is possible to suppress shape unevenness of a pattern of the organic mask and shrinkage of the organic mask. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a flow chart of a method for processing a substrate according to an exemplary embodiment.

[0007] Figure 2 (a) and Figure 2 (b) is a partially enlarged cross-sectional view of an example of a substrate.

[0008] Figure 3This is a diagram schematically showing a plasma processing apparatus according to an exemplary embodiment.

[0009] Figure 4 Yes Figure 3 FIG. 1 is a diagram showing an example of the structure of a DC power supply device of a plasma processing apparatus.

[0010] Figure 5 This is a timing chart showing an example of the high-frequency power and the output voltage of the DC power supply device of the plasma processing apparatus according to an exemplary embodiment.

[0011] Figure 6 (a) Figure 6 (b) Figure 6 (c) and Figure 6 (d) Yes Figure 1 A partially enlarged cross-sectional view of an example substrate after each treatment in the method shown. DETAILED DESCRIPTION

[0012] Various exemplary embodiments are described below.

[0013] In one exemplary embodiment, a method for processing a substrate is provided. The method includes (a) providing a substrate having a patterned organic mask into a chamber of a plasma processing apparatus. The method also includes (b) generating a plasma from a processing gas within the chamber while the substrate is contained within the chamber. The method also includes (c) periodically applying a pulsed negative DC voltage to an upper electrode of the plasma processing apparatus during the execution of (b). In (c), ions from the plasma are supplied to the upper electrode, and silicon-containing material released from the upper electrode is deposited onto the substrate.

[0014] The energy of ions that collide with the upper electrode from the plasma in the chamber has a tendency to become higher as the frequency of the voltage applied to the upper electrode becomes lower. In the method involved in the above embodiment, the energy of ions that collide with the upper electrode from the plasma in the chamber depends on the reciprocal of the period of the pulsed negative polarity DC voltage applied to the upper electrode, that is, the frequency (hereinafter referred to as "pulse frequency"). The pulse frequency can be set to a frequency lower than the frequency of the high-frequency power. Therefore, in the method involved in the above embodiment, ions with high energy can collide with the upper electrode. As a result, a relatively large amount of silicon-containing material can be released from the upper electrode and supplied to the substrate. According to the method involved in the above embodiment, a relatively large amount of silicon-containing material can be deposited on the substrate, thereby suppressing the uneven shape of the pattern of the organic mask and the shrinkage of the organic mask.

[0015] In an exemplary embodiment, the process gas may include at least one of argon, hydrogen, and nitrogen, and may be a mixed gas of argon and hydrogen.

[0016] In an exemplary embodiment, the duty ratio, which is the ratio of the time during which the pulsed negative DC voltage is applied in one cycle, may be 0.2 or more and 0.5 or less.

[0017] In an exemplary embodiment, the reciprocal of the period of the pulsed negative DC voltage applied to the upper electrode, that is, the frequency, may be lower than the frequency of the high-frequency power used to generate plasma. For example, the frequency may be 400 kHz or higher and 1 MHz or lower.

[0018] In an exemplary embodiment, the absolute value of the pulsed negative-polarity DC voltage may be greater than or equal to 500V and less than or equal to 1200V.

[0019] In an exemplary embodiment, the substrate may further include a film. The organic mask may be provided on the film. In this embodiment, the method may further include (d) etching the film using plasma generated from another process gas in the chamber.

[0020] In an exemplary embodiment, the above (b) and (d) may be performed using the same plasma processing apparatus or different plasma processing apparatuses.

[0021] In an exemplary embodiment, the sequence including the above (b), (c) and (d) may be repeated multiple times.

[0022] In another exemplary embodiment, a device manufacturing method is provided, which includes the step of processing a substrate having a patterned organic mask by any one of the methods described in the above embodiments.

[0023] In another exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a high-frequency power supply, an upper electrode, a DC power supply device, and a control unit. The substrate support is disposed in the chamber. The high-frequency power supply is configured to generate high-frequency power to generate plasma in the chamber. The upper electrode is disposed above the substrate support. The DC power supply device is connected to the upper electrode. The control unit is configured to control the high-frequency power supply and the DC power supply device. The control unit is configured to perform a process including the following (a), (b), and (c). (a) includes the step of providing a substrate having a patterned organic mask in the chamber. (b) includes the step of controlling the high-frequency power supply to supply high-frequency power, thereby generating plasma from a processing gas in the chamber. (c) includes the following steps: during the execution of (b), by controlling the DC power supply device, a pulsed negative-polarity DC voltage is periodically applied to the upper electrode to supply ions from the plasma to the upper electrode, thereby causing the silicon-containing material released from the upper electrode to be deposited on the substrate.

[0024] In an exemplary embodiment, the DC power supply device may include a variable DC power supply and a switching device.

[0025] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. In addition, in each of the drawings, the same or corresponding parts are marked with the same reference numerals.

[0026] Figure 1 is a flow chart of a method for processing a substrate according to an exemplary embodiment. Figure 1 The illustrated method (hereinafter referred to as "method MT") includes the steps of processing a substrate having an organic mask. Figure 2 (a) is a partially enlarged cross-sectional view of an example of a substrate. Figure 2 The substrate W shown in (a) has an organic mask OM. In one embodiment, the substrate W may further include a film MF and a bottom region UR. The film MF is disposed on the bottom region UR. The organic mask OM is disposed on the film MF. The organic mask OM is formed of an organic material and is patterned. The pattern of the organic mask OM may be a pattern transferred to the film MF. The organic mask OM is, for example, a photoresist mask. The organic mask OM can be formed, for example, using photolithography techniques.

[0027] The film MF may be a single layer film. Alternatively, Figure 2 As shown in (b), the film MF can also be a multilayer film. Figure 2 In the substrate W shown in (b), the film MF includes a film ARF, a film OF, and a film OXF. The film OXF is provided on the bottom surface region UR. The film OXF is, for example, a silicon oxide film. The film OF is provided on the film OXF. The film OF is, for example, an organic film. The film ARF is provided on the film OF. The film ARF is, for example, an anti-reflection film containing silicon.

[0028] Method MT includes steps ST1 and ST2. Method MT may further include providing a substrate W to a chamber of a plasma processing apparatus before performing step ST1. Steps ST1 and ST2 of method MT are performed with the substrate W accommodated in the chamber of the plasma processing apparatus. Figure 3 This is a diagram schematically showing a plasma processing apparatus according to an exemplary embodiment. Figure 3 The plasma processing apparatus 1 shown can be used in performing the method MT. The plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus.

[0029] The plasma processing apparatus 1 includes a chamber 10. The chamber 10 has an internal space 10s therein. The chamber 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The internal space 10s is provided inside the chamber body 12. The chamber body 12 is formed of a conductor such as aluminum. The chamber body 12 is grounded. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The corrosion-resistant film can be formed of a ceramic such as aluminum oxide or yttrium oxide.

[0030] A passage 12p is formed in the sidewall of the chamber body 12. The substrate W passes through the passage 12p when being transported between the internal space 10s and the outside of the chamber 10. The passage 12p can be opened and closed by a gate valve 12g provided along the sidewall of the chamber body 12.

[0031] A support portion 13 is provided at the bottom of the chamber body 12. The support portion 13 is formed of an insulating material and 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 supports a substrate support 14. The substrate support 14 is configured to support a substrate W within the chamber 10, i.e., within the internal space 10s.

[0032] The substrate support 14 includes a lower electrode 18 and an electrostatic chuck 20. The lower electrode 18 and the electrostatic chuck 20 are disposed within the chamber 10. The substrate support 14 may further include an electrode plate 16. The electrode plate 16 is formed of a conductor such as aluminum and has a generally disk-like shape. The lower electrode 18 is disposed on the electrode plate 16. The lower electrode 18 is formed of a conductor such as aluminum and has a generally disk-like shape. The lower electrode 18 is electrically connected to the electrode plate 16.

[0033] The electrostatic chuck 20 is disposed on the lower electrode 18. A substrate W is placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a main body and electrodes. The main body of the electrostatic chuck 20 is formed of a dielectric. The electrodes of the electrostatic chuck 20 are film-shaped electrodes and are disposed within the main body of the electrostatic chuck 20. The electrodes of the electrostatic chuck 20 are connected to a DC power supply 20p via a switch 20s. When a voltage from the DC power supply 20p is applied to the electrodes of the electrostatic chuck 20, an electrostatic attraction is generated between the electrostatic chuck 20 and the substrate W. The generated electrostatic attraction causes the substrate W to be attracted to the electrostatic chuck 20 and held by the electrostatic chuck 20.

[0034] An edge ring ER is disposed on the substrate support 14. The edge ring ER is not limited to any material and may be formed of silicon, silicon carbide, or quartz. When processing a substrate W in the chamber 10, the substrate W is disposed on the electrostatic chuck 20 within the area surrounded by the edge ring ER.

[0035] A flow path 18f is provided within the lower electrode 18. A heat exchange medium (e.g., a refrigerant) is supplied to the flow path 18f from a cooling unit 22 via a pipe 22a. The cooling unit 22 is provided outside the chamber 10. The heat exchange medium supplied to the flow path 18f is returned to the cooling unit 22 via a pipe 22b. In the plasma processing apparatus 1, the temperature of the substrate W placed on the electrostatic chuck 20 is adjusted by heat exchange between the heat exchange medium and the lower electrode 18.

[0036] The plasma processing apparatus 1 may further include a gas supply line 24 . The gas supply line 24 supplies a heat transfer gas (eg, He gas) to the gap between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W. The heat transfer gas is supplied to the gas supply line 24 from a heat transfer gas supply mechanism.

[0037] The plasma processing apparatus 1 further includes an upper electrode 30 . The upper electrode 30 is disposed above the substrate support 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 .

[0038] 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 is formed of a silicon-containing material. For example, the top plate 34 may be made of silicon, silicon carbide, or silicon oxide. A plurality of gas ejection holes 34a are formed in the top plate 34. The plurality of gas ejection holes 34a penetrate the top plate 34 in the thickness direction.

[0039] 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. A plurality of gas holes 36b are formed in the support body 36. The plurality of gas holes 36b extend downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are respectively connected to the plurality of gas discharge 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.

[0040] The gas source group 40 is connected to the gas supply pipe 38 via the valve group 41, the flow controller group 42, and the valve group 43. The gas source group 40, the valve group 41, the flow controller group 42, and the valve group 43 constitute the gas supply unit GS. The gas source group 40 includes multiple gas sources. Each of the valve group 41 and the valve group 43 includes multiple on-off valves. The flow controller group 42 includes multiple flow controllers. Each of the multiple flow controllers of the flow controller group 42 is a mass flow controller or a pressure-controlled flow controller. Each of the multiple gas sources of the gas source group 40 is connected to the gas supply pipe 38 via the corresponding on-off valve of the valve group 41, the corresponding flow controller of the flow controller group 42, and the corresponding on-off valve of the valve group 43.

[0041] In the plasma processing apparatus 1, a shield 46 is detachably provided along the inner wall surface of the chamber body 12. The shield 46 is also provided on the outer periphery of the support portion 13. The shield 46 prevents byproducts of the plasma treatment from adhering to the chamber body 12. The shield 46 is grounded. The shield 46 is formed, for example, by forming a corrosion-resistant film on the surface of a component formed of aluminum. The corrosion-resistant film can be a film formed of ceramics such as yttrium oxide. In addition, in one embodiment, the shield 46 provides an inner wall surface 10w of the side wall of the chamber 10. The inner wall surface 10w includes a first region 10a and a second region 10b. The first region 10a extends to the side of the internal space 10s. The second region 10b extends above the internal space 10s and to the side of the upper electrode 30. The first region 10a and the second region 10b can be provided not only by the shield 46 but also by one or more other components, such as the chamber body 12.

[0042] A partition 48 is provided between the support portion 13 and the sidewall of the chamber body 12. The partition 48 is formed, for example, by forming a corrosion-resistant film on the surface of an aluminum component. The corrosion-resistant film can be formed of a ceramic such as yttrium oxide. Multiple through-holes are formed in the partition 48. An exhaust port 12e is provided below the partition 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.

[0043] The plasma processing apparatus 1 further 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 for generating a first high-frequency power. In one example, the first high-frequency power has a frequency suitable for generating plasma. The frequency of the first high-frequency power is, for example, a frequency in the range of 27 MHz to 100 MHz. The first high-frequency power supply 62 is connected to the upper electrode 30 via a matching device 66. The matching device 66 has a circuit for matching the impedance of the load side (upper electrode 30 side) of the first high-frequency power supply 62 with the output impedance of the first high-frequency power supply 62. In addition, the first high-frequency power supply 62 can be connected to the lower electrode 18 via the matching device 66 and the electrode plate 16.

[0044] The second high-frequency power supply 64 is a power supply that generates a second high-frequency power. The second high-frequency power has a frequency lower than that of the first high-frequency power. The second high-frequency power can be used as a bias high-frequency power for introducing ions into the substrate W. The frequency of the second high-frequency power is, for example, a frequency in the range of 400 kHz to 40 MHz. The second high-frequency power supply 64 is connected to the lower electrode 18 via the matching device 68 and the electrode plate 16. The matching device 68 has a circuit for matching the impedance of the load side (lower electrode 18 side) of the second high-frequency power supply 64 with the output impedance of the second high-frequency power supply 64.

[0045] The plasma processing apparatus 1 further includes a DC power supply 70. The DC power supply 70 is electrically connected to the upper electrode 30. The DC power supply 70 is configured to periodically generate a pulsed negative-polarity DC voltage. Figure 4 Yes Figure 3 FIG. 1 is a diagram showing an example of the structure of a DC power supply device of a plasma processing apparatus. Figure 5 This is a timing chart showing an example of high-frequency power and an output voltage of a DC power supply device in a plasma processing apparatus according to an exemplary embodiment. Figure 5 , the horizontal axis represents time. Figure 5 In FIG. 1 , the vertical axis represents the supply of high-frequency power (the first high-frequency power and / or the second high-frequency power) and the output voltage of the DC power supply device 70 . Figure 5 In the middle, the high-frequency power is at a high level, which means that the high-frequency power is supplied. Figure 5 In the following, the high frequency power is low level, which means that the high frequency power is not supplied. Figure 3 For reference Figure 4 and Figure 5 .

[0046] In one embodiment, the DC power supply device 70 includes a variable DC power supply 70a and a switching device 70b. The variable DC power supply 70a is configured to generate a negative DC voltage. The level of the negative DC voltage output by the variable DC power supply 70a can be controlled by a control unit 80, described later. The switching device 70b switches between the variable DC power supply 70a and the upper electrode 30 by switching its conductive state. Switching the conductive state of the switching device 70b can also be controlled by the control unit 80.

[0047] To periodically output a pulsed negative DC voltage, the output voltage of the DC power supply device 70 is a negative DC voltage during the first period P1 within the period PT. In one embodiment, during the first period P1 within the period PT, the conductive state of the switching device 70b is switched to connect the variable DC power supply 70a and the upper electrode 30 to each other. The output voltage of the DC power supply device 70 is zero volts during the remaining second period P2 within the period PT. In one embodiment, during the second period P2 within the period PT, the conductive state of the switching device 70b is switched to disconnect the variable DC power supply 70a and the upper electrode 30.

[0048] In one embodiment, the ratio of the first period P1 within the period PT, i.e., the duty ratio (duty ratio expressed as a decimal), is greater than or equal to 0.2 and less than or equal to 0.5. The duty ratio is the ratio of the time during which the pulsed negative DC voltage is applied from the DC power supply 70 to the upper electrode 30 within the period PT.

[0049] In one embodiment, the frequency f, which is the inverse of the period PT, may be 400 kHz or higher. In one embodiment, the frequency f may be 1 MHz or lower. When the frequency f is 1 MHz or lower, the independent controllability of ion behavior relative to the generation of free radicals in the chamber 10 becomes higher.

[0050] In one embodiment, the absolute value of the pulsed negative-polarity DC voltage applied from the DC power supply device 70 to the upper electrode 30 during the first period P1 is 500 V or more and 1200 V or less.

[0051] The plasma processing apparatus 1 further includes a control unit 80. The control unit 80 may be a computer including 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 the various components of the plasma processing apparatus 1. In the control unit 80, an operator can use the input device to input instructions, etc., to manage the plasma processing apparatus 1. Furthermore, in the control unit 80, a display device can be used to visually display the operating status of the plasma processing apparatus 1. Furthermore, a control program and recipe data are stored in the storage unit of the control unit 80. The control program can be executed by the processor of the control unit 80 to perform various processes in the plasma processing apparatus 1. The processor of the control unit 80 executes the control program to control the various components of the plasma processing apparatus 1 according to the recipe data, thereby executing the method MT in the plasma processing apparatus 1.

[0052] Below, refer again Figure 1 , the method MT is described by taking the case where the method MT is performed by the plasma processing apparatus 1 as an example. In addition, the control of each part of the plasma processing apparatus 1 by the control unit 80 is also described. In the following description, reference is made to Figure 6 (a) Figure 6 (b) Figure 6 (c) and Figure 6 (d). Figure 6 (a) Figure 6 (b) Figure 6 (c) and Figure 6 (d) Yes Figure 1 A partially enlarged cross-sectional view of an example substrate after each treatment in the method shown.

[0053] In method MT, step ST1 is first performed. In step ST1, the process is performed in a state where the substrate W is accommodated in the chamber 10. The substrate W is placed on the substrate support 14 in the chamber 10 and is held by the electrostatic chuck 20. In step ST1, plasma of the processing gas is generated in the chamber 10. The processing gas is supplied by the gas supply unit GS. In one embodiment, the processing gas includes at least one of argon, hydrogen (H2 gas) and nitrogen (N2 gas). In one example, the processing gas is a mixed gas of argon and hydrogen. In addition, in step ST1, the first high-frequency power and / or the second high-frequency power are supplied to generate plasma from the processing gas in the chamber 10.

[0054] The control unit 80 controls the gas supply unit GS to supply processing gas into the chamber 10 to execute step ST1. The control unit 80 controls the exhaust device 50 to set the pressure in the chamber 10 to a specified pressure to execute step ST1. The control unit 80 controls the first high-frequency power supply 62 and / or the second high-frequency power supply 64 to supply the first high-frequency power and / or the second high-frequency power to execute step ST1.

[0055] Step ST2 is performed during step ST1. Specifically, step ST2 is performed when plasma is generated from the processing gas within chamber 10 during step ST1. Step ST2 is performed to supply ions from the plasma within chamber 10 to upper electrode 30, causing the silicon-containing material released from upper electrode 30 to be deposited onto substrate W. In step ST2, a pulsed negative DC voltage is periodically applied from DC power supply 70 to upper electrode 30. The control unit 80 controls DC power supply 70 to periodically apply the pulsed negative DC voltage to upper electrode 30, thereby performing step ST2.

[0056] In one embodiment, the duty ratio, which is the ratio of time during which the pulsed negative DC voltage is applied from the DC power supply device 70 to the upper electrode 30 within the period PT, is 0.2 or more and 0.5 or less.

[0057] In one embodiment, the frequency f, which is the inverse of the period PT, may be 400 kHz or higher. In one embodiment, the frequency f may be 1 MHz or lower. When the frequency f is 1 MHz or lower, the independent controllability of ion behavior relative to the generation of free radicals in the chamber 10 becomes higher.

[0058] In one embodiment, the absolute value of the pulsed negative-polarity DC voltage applied from the DC power supply device 70 to the upper electrode 30 in the first period P1 is 500 V or more and 1200 V or less.

[0059] In step ST2, positive ions are attracted from the plasma in the chamber 10 to the upper electrode 30 and collide with the top plate 34 of the upper electrode 30. As a result, secondary electrons and silicon-containing substances are released from the top plate 34 of the upper electrode 30. The released secondary electrons and silicon-containing substances are supplied to the substrate W. The organic mask OM on the substrate W can be modified by the secondary electrons. Figure 6 As shown in (a), the released silicon-containing substance is deposited on the organic mask OM on the substrate W to form a film DP.

[0060] The energy of ions colliding with the upper electrode 30 from the plasma in the chamber 10 tends to increase as the frequency of the voltage applied to the upper electrode 30 decreases. In method MT, the energy of ions colliding with the upper electrode 30 from the plasma in the chamber 10 depends on the frequency f, which is the inverse of the period PT of the pulsed negative DC voltage applied to the upper electrode 30. The frequency f can be set to a frequency lower than the frequency of the high-frequency power. Therefore, in method MT, ions with high energy can collide with the upper electrode 30. As a result, a relatively large amount of silicon-containing material can be released from the upper electrode 30 and supplied to the substrate W. According to method MT, a relatively large amount of silicon-containing material can be deposited on the substrate W, thereby suppressing uneven shape of the pattern of the organic mask OM and reducing the size of the organic mask OM. In addition, uneven shape of the pattern of the organic mask OM can be evaluated, for example, using LWR (Line Width Roughness).

[0061] In one embodiment, the method MT may further include a step ST3. In the step ST3, the film MF is etched. The film MF may be etched using the plasma processing apparatus 1. Alternatively, the film MF may be etched using other plasma processing apparatuses. Figure 2 The step ST3 will be described using the case of the film MF shown in (b) as an example.

[0062] First, plasma of other processing gases is generated in the chamber 10 to perform plasma etching of the film ARF. In the case where the film ARF is a silicon-containing anti-reflective film, the processing gas used for plasma etching of the film ARF may include a fluorine-containing gas such as a fluorocarbon gas. The control unit 80 controls the gas supply unit GS to supply processing gas into the chamber 10 to perform plasma etching of the film ARF. The control unit 80 controls the exhaust device 50 to set the pressure in the chamber 10 to a specified pressure to perform plasma etching of the film ARF. The control unit 80 controls the first high-frequency power supply 62 and / or the second high-frequency power supply 64 to supply the first high-frequency power and / or the second high-frequency power to perform plasma etching of the film ARF. The result of the plasma etching of the film ARF, such as Figure 6 As shown in (b), the pattern of the organic mask OM whose width is adjusted by the film DP is transferred to the film ARF.

[0063] Then, plasma of other processing gases is also generated in the chamber 10 to perform plasma etching of the film OF. In the case where the film OF is an organic film, the processing gas used for plasma etching of the film OF may include hydrogen and nitrogen. Alternatively, the processing gas used for plasma etching of the film OF may include an oxygen-containing gas. The control unit 80 controls the gas supply unit GS to supply processing gas into the chamber 10 to perform plasma etching of the film OF. The control unit 80 controls the exhaust device 50 to set the pressure in the chamber 10 to a specified pressure to perform plasma etching of the film OF. The control unit 80 controls the first high-frequency power supply 62 and / or the second high-frequency power supply 64 to supply the first high-frequency power and / or the second high-frequency power to perform plasma etching of the film OF. The result of the plasma etching of the film OF, as shown in FIG. Figure 6 As shown in (c), the pattern of the film ARF is transferred to the film OF.

[0064] Then, plasma of other processing gases is also generated in the chamber 10 to perform plasma etching of the film OXF. In the case where the film OXF is a silicon oxide film, the processing gas used for plasma etching of the film OXF may include a fluorocarbon gas. The control unit 80 controls the gas supply unit GS to supply processing gas into the chamber 10 to perform plasma etching of the film OXF. The control unit 80 controls the exhaust device 50 to set the pressure in the chamber 10 to a specified pressure to perform plasma etching of the film OXF. The control unit 80 controls the first high-frequency power supply 62 and / or the second high-frequency power supply 64 to supply the first high-frequency power and / or the second high-frequency power to perform plasma etching of the film OXF. The result of the plasma etching of the film OXF, as shown in FIG. Figure 6 As shown in (d), the pattern of the film OF is transferred to the film OXF.

[0065] Although various exemplary embodiments have been described above, the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and changes may be made. Furthermore, elements of different embodiments may be combined to form another embodiment.

[0066] For example, in method MT, a sequence including step ST1 , step ST2 , and step ST3 may be repeated multiple times.

[0067] The following describes the first and second experiments conducted to evaluate the MT method. Figure 2(b) A sample substrate having the same structure as the substrate W shown. On the sample substrate, the organic mask OM is a photoresist mask. On the sample substrate, the film ARF is a silicon-containing anti-reflection film. On the sample substrate, the film OF is an organic film. On the sample substrate, the film OXF is a silicon oxide film. The organic mask OM of the sample substrate has a line and space pattern. In the organic mask OM of the sample substrate, the average value of the line width is 41.8 nm, and the LWR of the line is 3.3 nm. In the first experiment, using the plasma processing device 1, the process ST1 and process ST2 of the method MT were applied to the sample substrate. In the process ST2 of the first experiment, the absolute value of the pulsed negative polarity DC voltage applied to the upper electrode 30 was -900 V, the frequency f of the pulsed negative polarity DC voltage was 400 kHz, and the duty cycle of the pulsed negative polarity DC voltage was 0.5. The conditions of the process ST1 and process ST2 in the first experiment are shown below.

[0068] <Conditions of Steps ST1 and ST2 in the First Experiment>

[0069] Processing time: 10 seconds

[0070] Pressure in chamber 10: 100 mTorr (13.33 Pa)

[0071] 1st high frequency power: 60MHz, 300W

[0072] Second high-frequency power: 0W

[0073] Processing gas: 10 sccm H2 gas and 800 sccm Ar gas

[0074] In the second experiment, plasma of the processing gas was generated using the plasma processing apparatus 1 under the same conditions as those of the first experiment, and a DC voltage of −900 V was continuously applied to the upper electrode 30 to process the sample substrate.

[0075] In the first experiment and the second experiment, the average value of the line width and the LWR of the organic mask OM whose shape was adjusted by depositing a silicon-containing material thereon were respectively determined. In the first experiment, the average value of the line width was 41.8 nm and the LWR was 2.8 nm. In the second experiment, the average value of the line width was 40.6 nm and the LWR was 2.7 nm. In both the first and second experiments, the LWR after treatment became smaller than the LWR of the sample substrate before treatment. Moreover, in the second experiment, the average value of the line width after treatment was smaller than the average value of the line width before treatment, but in the first experiment, the average value of the line width after treatment was the same as the average value of the line width before treatment. Therefore, it was confirmed that according to method MT, the shape unevenness of the pattern of the organic mask and the reduction of the organic mask can be suppressed.

[0076] As can be seen from the above description, the various embodiments of the present invention are described in this specification for illustrative purposes and various modifications may be made without departing from the scope and spirit of the present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are shown by the scope of the attached technical solutions.

Claims

1. A method for processing a substrate, comprising: (a) providing a substrate having a patterned organic mask into a chamber of a plasma processing apparatus; (b) generating plasma from a processing gas in the chamber while the substrate is housed in the chamber; and (c) During the execution of (b), a pulsed negative DC voltage is periodically applied from a DC power supply device to an upper electrode of the plasma processing device to supply ions originating from the plasma to the upper electrode, thereby causing the silicon-containing material released from the upper electrode to be deposited on the substrate. The duty ratio, which is the ratio of the time during which the pulsed negative DC voltage is applied to the upper electrode in one cycle, is 0.2 or more and 0.5 or less. The negative-polarity pulsed DC voltage is applied to the upper electrode at a frequency that is the inverse of a period of 400 kHz or more and 1 MHz or less. The reciprocal of a period of applying the pulsed negative-polarity DC voltage to the upper electrode, that is, a frequency, is lower than a frequency of high-frequency power for generating the plasma.

2. The method for processing a substrate according to claim 1, wherein: The processing gas includes at least one of argon, hydrogen and nitrogen.

3. The method for processing a substrate according to claim 1, wherein: The processing gas is a mixed gas of argon and hydrogen.

4. The method for processing a substrate according to any one of claims 1 to 3, wherein: The output voltage of the DC power supply device in the one cycle is zero volt during a period in which the pulsed negative DC voltage is not applied.

5. The method for processing a substrate according to any one of claims 1 to 3, wherein: An absolute value of the pulsed negative-polarity DC voltage is 500 V or more and 1200 V or less.

6. The method for processing a substrate according to any one of claims 1 to 3, wherein: The substrate further has a film, and the organic mask is provided on the film. The method further includes the step of (d) etching the film in the chamber using plasma generated from another process gas.

7. The method for processing a substrate according to claim 6, wherein: The steps (b) and (d) are performed using the same plasma processing apparatus.

8. The method for processing a substrate according to claim 6, wherein: (b) and (d) are performed using different plasma processing apparatuses.

9. The method for processing a substrate according to claim 6, wherein: The sequence of (b), (c) and (d) is repeated multiple times. 10 . A device manufacturing method comprising the step of processing a substrate having a patterned organic mask by the method for processing a substrate according to claim 1 .

11. A plasma processing apparatus comprising: chamber; a substrate supporter, disposed in the chamber; a high-frequency power supply for generating high-frequency power to generate plasma in the chamber; an upper electrode disposed above the substrate support; a DC power supply device connected to the upper electrode; and a control unit configured to control the high frequency power supply and the DC power supply device, The control unit is configured to execute a process including the following steps: (a) providing a substrate having a patterned organic mask into the chamber; (b) controlling the high-frequency power supply to supply high-frequency power, thereby generating plasma from the processing gas in the chamber; and (c) During the execution of (b), the DC power supply device is controlled to periodically apply a pulsed negative DC voltage to the upper electrode to supply ions from the plasma to the upper electrode, thereby causing the silicon-containing material released from the upper electrode to be deposited on the substrate. The duty ratio, which is the ratio of the time during which the pulsed negative DC voltage is applied to the upper electrode in one cycle, is 0.2 or more and 0.5 or less. The negative-polarity pulsed DC voltage is applied to the upper electrode at a frequency that is the inverse of a period of 400 kHz or more and 1 MHz or less. The reciprocal of a period of applying the pulsed negative-polarity DC voltage to the upper electrode, that is, a frequency, is lower than a frequency of high-frequency power for generating the plasma.

12. The plasma processing apparatus according to claim 11, wherein: The DC power supply device includes a variable DC power supply and a switching device.

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