Plasma processing method and plasma processing system

Abstract

A plasma processing method performed in a plasma processing apparatus having a chamber is provided. The method includes: (a) a step of preparing a substrate having a film to be etched and a metal-containing film provided on the film to be etched on a substrate support portion in a chamber, the metal-containing film having a first region that is exposed and a second region that is not exposed; (b) a step for modifying the metal-containing film using a first plasma generated from a first processing gas including either a fluorine-containing gas or an oxygen-containing gas; and (c) a step for selectively removing the first region of the modified metal-containing film from the second region using a second plasma generated from a second processing gas.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a plasma processing method and a plasma processing system. Background Art

[0002] Patent Document 1 discloses a technique for trimming a non-organic film.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent Application Publication No. 2017 / 0243744 Summary of the invention

[0006] The present disclosure provides a plasma treatment method that can form fine patterns on a metal-containing film.

[0007] In an exemplary embodiment of the present disclosure, a plasma processing method is provided, which is a plasma processing method performed in a plasma processing device having a chamber, comprising: (a) preparing a substrate having an etching target film and a metal-containing film disposed on the etching target film on a substrate support portion in the chamber, wherein the metal-containing film has an exposed first region and an unexposed second region; (b) modifying the metal-containing film using a first plasma generated by a first processing gas including either a fluorine-containing gas or an oxygen-containing gas; and (c) selectively removing the first region of the modified metal-containing film relative to the second region using a second plasma generated by a second processing gas.

[0008] Effects of the Invention

[0009] According to an exemplary embodiment of the present disclosure, it is possible to provide a plasma treatment method that can form a fine pattern on a metal-containing film. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram schematically illustrating an exemplary plasma processing system.

[0011] Figure 2 is a flowchart showing the present processing method.

[0012] Figure 3 1 is a diagram schematically showing an example of a cross-sectional structure of a substrate W provided in step ST1 .

[0013] Figure 4 1 is a diagram schematically showing an example of a cross-sectional structure of the substrate W after being processed in step ST2 .

[0014] Figure 5 1 is a diagram schematically showing an example of a cross-sectional structure of the substrate W after being processed in step ST3 .

[0015] Figure 6 1 is a diagram schematically showing an example of a cross-sectional structure of the substrate W after being processed in step ST4 .

[0016] Description of Reference Numerals

[0017] 1…plasma processing apparatus, 2…control unit, 10…plasma processing chamber, 10s…plasma processing space, 11…substrate supporting unit, 20…microwave plasma source, 30…gas supply unit, 40…bias power supply, 50…exhaust system, MF, MF…metal-containing film, EF…etching target film, UF…base film, MF1, MF1a…first region, MF2, MF2a…second region, OP…opening, RC…recess, W…substrate. DETAILED DESCRIPTION

[0018] Hereinafter, each embodiment of the present disclosure will be described.

[0019] In an exemplary embodiment, a plasma processing method is provided, which is a plasma processing method performed in a plasma processing apparatus having a chamber, comprising: (a) preparing a substrate having an etching target film and a metal-containing film disposed on the etching target film on a substrate support portion in the chamber, the metal-containing film having an exposed first region and an unexposed second region; (b) modifying the metal-containing film using a first plasma generated by a first processing gas including either a fluorine-containing gas or an oxygen-containing gas; and (c) selectively removing the modified first region of the metal-containing film relative to the second region using a second plasma generated by a second processing gas.

[0020] In one exemplary embodiment, through the modification in step (b), the etching resistance of the second region to the second plasma is greater than the etching resistance of the first region to the second plasma.

[0021] In one exemplary embodiment, the step (c) removes the first region to expose the etching target film.

[0022] In one exemplary embodiment, the metal-containing film includes tin or titanium.

[0023] In one exemplary embodiment, the metal-containing film includes an organic substance.

[0024] In an exemplary embodiment, the first process gas includes at least one gas selected from the group consisting of fluorocarbon gas, hydrofluorocarbon gas, NF3 gas, and SF6 gas.

[0025] In one exemplary embodiment, the second process gas includes a chlorine-containing gas.

[0026] In an exemplary embodiment, the chlorine-containing gas is BCl 3 or Cl 2 gas.

[0027] In an exemplary embodiment, the first process gas includes at least one gas selected from the group consisting of O 2 gas, CO gas, and CO 2 gas.

[0028] In one exemplary embodiment, the first process gas further includes a chlorine-containing gas.

[0029] In an exemplary embodiment, the chlorine-containing gas is at least one gas selected from the group consisting of Cl 2 gas, BCl 3 gas, and SiCl 4 gas.

[0030] In one exemplary embodiment, for step (c), generating the second plasma using a gas including a hydrogen-containing gas and a nitrogen-containing gas as the second process gas and generating the second plasma using a gas including a chlorine-containing gas as the second process gas are repeated alternately.

[0031] In one exemplary embodiment, the etching target film is a silicon-containing film or a carbon-containing film.

[0032] In one exemplary embodiment, after step (c), the method further includes a step (d) of etching the etching target film using the metal-containing film as a mask.

[0033] In an exemplary embodiment, steps (a) to (d) are performed in the same chamber.

[0034] In one exemplary embodiment, the metal-containing film includes a metal-containing photoresist film, the first region is an exposed region in the metal-containing photoresist film, and the second region is an unexposed region in the metal-containing photoresist.

[0035] In one exemplary embodiment, the first region is EUV exposed.

[0036] In an exemplary embodiment, a plasma processing system is provided, comprising a chamber, a substrate support portion disposed in the chamber, and a control portion, the control portion performing the following control, the control comprising: (a) control of preparing a substrate having an etching target film and a metal-containing film disposed on the etching target film on the substrate support portion, the metal-containing film having an exposed first region and an unexposed second region; (b) control of modifying the metal-containing film using a first plasma generated by a first processing gas including either a fluorine-containing gas or an oxygen-containing gas; and (c) control of selectively removing the modified first region of the metal-containing film relative to the second region using a second plasma generated by a second processing gas.

[0037] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the same symbols are used to mark the same or identical elements in each of the drawings, and repeated descriptions are omitted. Unless otherwise specified, the positional relationships such as up, down, left, and right are described based on the positional relationships shown in the drawings. The dimensional ratios of the drawings do not represent the actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0038] <Configuration Example of Plasma Processing System>

[0039] Hereinafter, a configuration example of a plasma processing system will be described. Figure 1 is a diagram schematically illustrating an exemplary plasma processing system.

[0040] The plasma processing system includes a plasma processing device 1 using a microwave plasma source and a control unit 2. The plasma processing device 1 includes a plasma processing chamber 10, a microwave plasma source 20, a gas supply unit 30, a bias power supply 40, and an exhaust system 50. In addition, the plasma processing device 1 includes a substrate support unit 11 and a gas introduction unit. The substrate support unit 11 is arranged in the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by an annular support unit 101, a side wall 102 of the plasma processing chamber 10, an exhaust chamber 103, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas exhaust port for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded.

[0041] The substrate support portion 11 includes a main body 111, a ring assembly 112, and a support member 113. The main body 111 has a central area 111a for supporting a substrate W and an annular area 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular area 111b of the main body 111 surrounds the central area 111a of the main body 111 when viewed from above. The substrate W is arranged on the central area 111a of the main body 111, and the ring assembly 112 is arranged on the annular area 111b of the main body 111 in a manner of surrounding the substrate W on the central area 111a of the main body 111. Therefore, the central area 111a is also referred to as a substrate supporting surface for supporting the substrate W, and the annular area 111b is also referred to as a ring supporting surface for supporting the ring assembly 112.

[0042] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can be used as a bias electrode. The electrostatic chuck 1111 is configured on the base 1110. The electrostatic chuck 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b configured in the ceramic component 1111a. The ceramic component 1111a has a central area 111a. In one embodiment, the ceramic component 1111a also includes an annular area 111b. In addition, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating component, may also have an annular area 111b. In this case, the ring assembly 112 may be arranged on the annular electrostatic chuck or the annular insulating component, or on both the electrostatic chuck 1111 and the annular insulating component. In addition, at least one RF / DC electrode coupled to the RF (Radio Frequency) power supply 41 and / or the DC (Direct Current) power supply 42 described later may also be disposed in the ceramic component 1111a. In this case, at least one RF / DC electrode is used as a bias electrode. In addition, the conductive component of the base 1110 and at least one RF / DC electrode may also be used as a plurality of bias electrodes. In addition, the electrostatic electrode 1111b may also be used as a bias electrode. Therefore, the substrate support portion 11 includes at least one bias electrode.

[0043] The ring assembly 112 includes one or more ring components. In one embodiment, the one or more ring components include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0044] The support member 113 is a member that supports the main body 111. The support member 113 may be in a cylindrical shape extending upward from the center of the bottom of the exhaust chamber 103. The support member 113 is formed of a ceramic material such as AlN.

[0045] In addition, the substrate support portion 11 may also include a temperature control module, which is configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112 and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are arranged in the ceramic component 1111a of the electrostatic chuck 1111. In addition, the substrate support portion 11 may also include a heat transfer gas supply portion, which is configured to supply a heat transfer gas to the gap between the back side of the substrate W and the central area 111a.

[0046] The microwave plasma source 20 is supported by the support 101. The microwave plasma source 20 includes a microwave transmitting plate 21, a planar slot antenna 22, a slow wave material 23, a cooling jacket 24, a coaxial waveguide 25, a mode converter 26, a waveguide 27 and a microwave generator 28.

[0047] The microwave transmitting plate 21 is airtightly formed at the support portion via a sealing member, so that the plasma processing chamber 10 maintains airtightness. The microwave transmitting plate 21 may be a disc-shaped dielectric formed of ceramics such as quartz or Al2O3.

[0048] The planar slot antenna 22 has a plurality of slots and is formed in a disk shape corresponding to the microwave transmitting plate 21 so as to be in close contact with the microwave transmitting plate 21. The planar slot antenna 22 may be engaged with the upper end of the side wall 102 of the plasma processing chamber 10.

[0049] The planar slot antenna 22 can be, for example, a conductor in the shape of a circular plate. In addition, the planar slot antenna 22 is, for example, composed of a copper plate or an aluminum plate with a silver or gold plated surface, and is formed into a plurality of slots for radiating microwaves that penetrate in a prescribed pattern. The pattern of the slots can be set so that microwaves are uniformly radiated on the substrate W. The pattern of the slots can, for example, include two slots arranged in a T-shape as a pair and multiple pairs of slots arranged in concentric circles. The length and arrangement interval of the slots are determined according to the effective wavelength (λg) of the microwaves. For example, the slots can be arranged so that the interval between the slots is λg / 4, λg / 2 or λg. In addition, the slots can also be in other shapes such as a circle or an arc. In addition, the configuration of the slots is not particularly limited. In addition to the concentric circle shape, for example, it can also be configured in a spiral shape or a radial shape. In addition, the planar slot antenna 22 can be configured separately from the microwave transparent plate 21.

[0050] The slow-wave material 23 is arranged close to the top of the planar slot antenna 22. The slow-wave material 23 can be a dielectric having a dielectric constant greater than that of a vacuum. The slow-wave material 23 can be formed of, for example, quartz, ceramic (Al2O3), polytetrafluoroethylene, polyimide, and other resins. The slow-wave material 23 has the function of making the wavelength of microwaves shorter than that in a vacuum and adjusting the phase of microwaves. In addition, the slow-wave component 23 can be configured separately from the planar slot antenna 22.

[0051] The thickness of the microwave transmitting plate 21 and the slow-wave material 23 is adjusted so that the equivalent circuit formed by the microwave transmitting plate 21, the planar slot antenna 22 and the slow-wave material 23 satisfies the resonance condition. By adjusting the thickness of the slow-wave material 23, the phase of the microwave can be adjusted. By adjusting the thickness of the slow-wave material 23, the joint between the planar slot antenna 22 and the slow-wave material 23 becomes the "antinode" of the standing wave, so that the reflection of the microwave is minimized and the radiation energy of the microwave is maximized. In addition, the microwave transmitting plate 21 and the slow-wave material 23 can also be made of the same material to suppress the interface reflection of the microwave.

[0052] The cooling jacket 24 is provided to cover the planar slot antenna 22 and the slow-wave material 23 on the upper surface of the plasma processing chamber 10. The cooling jacket 24 may be a heat conductor made of a metal material such as aluminum, stainless steel, copper, etc. A cooling water flow path 24a is provided in the cooling jacket 24. By allowing cooling water to flow through the cooling water flow path 24a, the microwave transmitting plate 21, the planar slot antenna 22, and the slow-wave material 23 are cooled.

[0053] The coaxial waveguide 25 is inserted from above the opening provided in the center of the cooling jacket 24 toward the microwave transmitting plate 21. A hollow rod-shaped inner conductor 25a and a cylindrical outer conductor 25b are concentrically arranged in the coaxial waveguide 25. The upper end of the coaxial waveguide 25 is connected to the mode converter 26. The lower end of the inner conductor 25a is connected to the planar slot antenna 22. The lower end of the outer conductor 25b is connected to the slow wave material 23.

[0054] The mode converter 26 is configured by connecting a microwave generator 28 via a horizontally extending waveguide 27 having a rectangular cross section. The mode converter 26 has a function of converting a vibration mode of microwaves.

[0055] The waveguide 27 is configured such that one end is connected to the mode converter 26 and the other end is connected to the microwave generator 28. The waveguide 27 includes a matching circuit 27a.

[0056] The microwave generator 28 generates microwaves with a frequency of, for example, 2.45 GHz. The generated microwaves propagate in the waveguide 27, and the vibration mode is converted from the TE mode to the TEM mode by the mode converter 26, and propagates to the slow-wave material 23 via the coaxial waveguide 25. The microwaves radially expand radially outward inside the slow-wave material 23 and are radiated from the slots of the planar slot antenna 22. The radiated microwaves pass through the microwave transmitting plate 21, and an electric field is generated in the plasma processing space 10s directly below, and microwave plasma is generated by the processing gas in the plasma processing space 10s. An annular recess 21a with a conical depression can be formed on the lower surface of the microwave transmitting plate 21, and microwave plasma can be generated efficiently.

[0057] In addition, as the frequency of the microwave, in addition to 2.45 GHz, various frequencies such as 8.35 GHz, 1.98 GHz, 860 MHz, and 915 MHz can be used. In addition, in one example, the power of the microwave can be between 2000 and 5000 W, and the power density can be between 2.8 and 7.1 W / cm 2 the following.

[0058] The gas supply unit 30 may include at least one gas source 31 and at least one flow controller 32. In one embodiment, the gas supply unit 30 is configured to supply at least one process gas from the respective gas sources 31 to the gas introduction unit via the respective flow controllers 32. Each flow controller 32 may include, for example, a mass flow controller or a pressure control flow controller. Furthermore, the gas supply unit 30 may include one or more flow modulation devices for modulating or pulsing the flow of at least one process gas.

[0059] The gas introduction part is configured to introduce at least one processing gas from the gas supply part 30 into the plasma processing space 10s. In one embodiment, the gas introduction part includes a gas flow path 33 formed inside the mode converter 26 and the inner conductor 25a of the coaxial waveguide 25, and a gas supply port 34 at the front end of the gas flow path opens in the plasma processing space 10s, for example, at the central part of the microwave transparent plate 21. The processing gas introduced from the gas supply part 30 to the gas introduction part is supplied from the gas supply port 34 to the plasma processing space 10s through the gas flow path 33. In addition, in addition to the gas flow path 33, the gas introduction part may also include one or more side gas injection parts (SGI: Side Gas Injector) installed on one or more openings formed on the side wall 102.

[0060] The bias power supply 40 includes an RF power supply 41, which is coupled to the plasma processing chamber 10 through at least one impedance matching circuit. The RF power supply 41 is configured to provide an RF signal (RF power) to the bias electrode. Thus, by supplying at least one bias RF signal to the bias electrode, a bias potential is generated on the substrate W, and ions in the formed plasma can be introduced into the substrate W.

[0061] In one embodiment, the RF power supply 41 includes an RF generating unit 41a. The RF generating unit 41a is coupled to at least one bias electrode via at least one impedance matching circuit to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a frequency in the range of 100kHz to 60MHz. In one embodiment, the RF generating unit 41a may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are provided to at least one bias electrode. In addition, in various embodiments, the bias RF signal may be pulsed.

[0062] In addition, the bias power supply 40 may include a DC power supply 42 coupled to the plasma processing chamber 10. The DC power supply 42 includes a bias DC generating unit 42a. In one embodiment, the bias DC generating unit 42a is connected to at least one bias electrode to generate a bias DC signal. The generated bias DC signal is applied to at least one bias electrode.

[0063] In various embodiments, the bias DC signal may be pulsed. In this case, a voltage pulse sequence is applied to at least one bias electrode. The voltage pulse may have a pulse waveform of a rectangle, a trapezoid, a triangle, or a combination thereof. In one embodiment, a waveform generating unit for generating a voltage pulse sequence from a DC signal is connected between the bias DC generating unit 42a and at least one bias electrode. Therefore, the bias DC generating unit 42a and the waveform generating unit constitute a voltage pulse generating unit. The voltage pulse may have a positive polarity or a negative polarity. In addition, the voltage pulse sequence may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses in one cycle. In addition, the bias DC generating unit 42a may also be provided on the basis of the RF power supply 41.

[0064] The exhaust system 50 may be connected to a gas outlet 51 provided in the exhaust chamber 103. The exhaust system 50 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0065] The control unit 2 processes computer-executable instructions that cause the plasma processing device 1 to perform various processes described in the present disclosure. The control unit 2 can be configured to control the various elements of the plasma processing device 1 to perform the various processes described herein. In one embodiment, a part or all of the control unit 2 can be included in the plasma processing device 1. The control unit 2 can also include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 can be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. The program can be pre-stored in the storage unit 2a2, or it can be obtained via a medium when necessary. The obtained program is stored in the storage unit 2a2, and is read and executed from the storage unit 2a2 by the processing unit 2a1. The medium can be various storage media readable by the computer 2a, and can be a communication circuit connected to the communication interface 2a3. The processing unit 2a1 can also be a CPU (Central Processing Unit). The storage unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive) or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication circuit such as a LAN (Local Area Network).

[0066] <An Example of Plasma Treatment Method>

[0067] Figure 2 1 is a flow chart showing a plasma treatment method according to an exemplary embodiment (hereinafter also referred to as "the present treatment method"). Figure 2 As shown in FIG. 1 , the processing method includes: a step ST1 of preparing a substrate, a step ST2 of modifying the metal-containing film (hereinafter also referred to as “modification processing”), and a step ST3 of developing the metal-containing film (hereinafter also referred to as “development processing”). The processing method may also include a step ST4 of etching the etching target film. The processing in each step may be performed in Figure 1 Hereinafter, the processing method will be described by taking the case where the control unit 2 controls each part of the plasma processing apparatus 1 to execute the processing method on the substrate W as an example.

[0068] (Step ST1: Preparation of substrate)

[0069] In step ST1 , a substrate W is prepared in the plasma processing chamber 10 s of the plasma processing apparatus 1 . The substrate W is disposed in the central region 111 a of the substrate support 11 . The substrate W is held by the electrostatic chuck 1111 .

[0070] After the substrate W is arranged in the central area 111a of the substrate support part 11, the temperature of the substrate support part 11 can be adjusted to a set temperature by a temperature control module. The set temperature can be, for example, a temperature below 60°C (in one example, room temperature). In one example, adjusting or maintaining the temperature of the substrate support part 11 includes adjusting or maintaining the temperature of the heat transfer fluid flowing through the flow path 1110a at a set temperature or a temperature different from the set temperature. In one example, adjusting or maintaining the temperature of the substrate support part 11 includes controlling the pressure of the heat transfer gas (for example, He) between the electrostatic chuck 1111 and the back of the substrate W. In addition, the time point when the heat transfer fluid starts to flow to the flow path 1110a can be before or after the substrate W is placed on the substrate support part 11, or it can flow at the same time. In addition, in the present processing method, the temperature of the substrate support part 11 can be adjusted to a set temperature before step ST1. That is, the substrate W can be prepared in the substrate support part 11 after the temperature of the substrate support part 11 is adjusted to the set temperature. In the subsequent steps of the present processing method, the temperature of the substrate support part 11 is maintained at the set temperature adjusted in step ST1.

[0071] Figure 3 1 is a diagram showing an example of a cross-sectional structure of a substrate W prepared in step ST1. The substrate W has an etching target film EF and a metal-containing film MF stacked in sequence on a base film UF. The substrate W can be used to manufacture a semiconductor device. The semiconductor device includes, for example, a semiconductor storage device such as a DRAM or a 3D-NAND flash memory.

[0072] In one example, the base film UF is a silicon wafer or a carbon-containing film formed on the silicon wafer, a dielectric film, a metal film, a semiconductor film, etc. The base film UF may be formed by stacking a plurality of films.

[0073] The etching target film EF is a film different from the base film UF. The etching target film EF may be, for example, a carbon-containing film, a dielectric film, a semiconductor film, or a metal film. The etching target film EF may be composed of a single film or a plurality of films stacked. For example, the etching target film EF may be composed of a single or multiple film stacks of a silicon-containing film, a carbon-containing film, a spin-on-glass (SOG) film, a Si-containing anti-reflection film (SiARC), or the like.

[0074] The base film UF and the etching target film EF constituting the substrate W can be formed by CVD, ALD, spin coating, etc. The base film UF and the etching target film EF may be flat films or films having projections and depressions.

[0075] The metal-containing film MF is formed on the upper surface of the etching target film EF. The metal-containing film MF is a film containing metal, and has an exposed first region MF1 and an unexposed second region MF2.

[0076] The metal-containing film MF is a "negative" film. That is, the first region MF1 to be exposed has higher etching resistance to the plasma used in the development process than the second region MF2 to be unexposed. For example, when the metal-containing film MF is exposed to the second plasma used in the development process of step ST3, the second region MF2 to be unexposed is removed, and the first region MF1 to be exposed remains.

[0077] The metal-containing film MF may be a film containing tin or titanium. In one example, the metal-containing film may include tin oxide. The metal-containing film MF may contain organic matter. The metal-containing film MF may contain different components and / or their content ratios in the first region MF1 and the second region MF2. In one example, the film constituting the first region MF1 may contain oxygen, carbon, and tin. In one example, the film constituting the second region MF2 may contain carbon and tin. The film constituting the first region MF1 and / or the second region MF2 may also contain silicon.

[0078] The metal-containing film MF can be formed by photolithography. For example, a photoresist film containing metal is first formed on the etching target film EF. Then, light (such as EUV excimer laser, etc.) is selectively irradiated to the photoresist film through an exposure mask. Thus, a metal-containing film MF having an exposed first region MF1 and an unexposed second region MF2 is formed. The first region MF1 is a region corresponding to an opening provided on the exposure mask. The second region MF2 is a region corresponding to a pattern provided on the exposure mask.

[0079] At least a part of the process of forming each structure of the substrate W may be performed in the plasma processing space 10s. Alternatively, the substrate W may be provided in the plasma processing space 10s after all or part of each structure of the substrate W is formed by an apparatus or chamber outside the substrate processing apparatus 1.

[0080] (Step ST2: Modification of Metal-Containing Film)

[0081] In step ST2, the metal-containing film MF is modified. First, a first process gas is supplied from a gas supply unit 30 into a plasma processing chamber 10s. The first process gas includes any one of a fluorine-containing gas or an oxygen-containing gas. Next, microwaves are radiated into the plasma processing chamber 10s from a microwave plasma source 20. Thus, a first plasma containing active species of fluorine or oxygen is generated from the first process gas. The metal-containing film MF is modified by exposure to the first plasma. The modification may include fluorinating or oxidizing the metal-containing film MF. The modification may include changing at least a portion of the components and / or the ratio of the components of the metal-containing film MF. The modification may include solidifying part or all of the metal-containing film MF, or solidifying a portion of the metal-containing film MF compared to other portions.

[0082] The first processing gas may include a fluorine-containing gas. In one example, the fluorine-containing gas may be at least one gas selected from the group consisting of fluorocarbon gas, hydrofluorocarbon gas, NF3 gas, and SF6 gas. In one example, the fluorocarbon gas may be at least one gas selected from the group consisting of CF4 gas, C2F2 gas, C2F4 gas, C3F6 gas, C3F8 gas, C4F6 gas, C4F8 gas, and C5F8 gas. In one example, the hydrofluorocarbon gas may be selected from the group consisting of CHF3 gas, CH2F2 gas, CH3F gas, C2HF5 gas, C2H2F4 gas, C2H3F3 gas, C2H4F2 gas, C3HF7 gas, C3H2F2 gas, C3H2F4 gas, C3H2F6 gas, C3H3F5 gas, C4H2F6 gas, C4H5F5 gas, C4H2F8 gas, C5H2F6 gas, C5H2F 10 At least one of the group consisting of gas, C5H3F7 gas.

[0083] The first process gas may contain an oxygen-containing gas instead of a fluorine-containing gas. The oxygen-containing gas may be at least one gas selected from the group consisting of O2 gas, CO gas, and CO2 gas in one example. When the first process gas includes an oxygen-containing gas, the first process gas may also include a chlorine-containing gas. The chlorine-containing gas may be at least one gas selected from the group consisting of HCl gas, Cl2 gas, BCl3 gas, and SiCl4 gas in one example.

[0084] The first processing gas may further include an inert gas such as a rare gas or N 2 gas.

[0085] Figure 4 FIG. 2 is a diagram showing an example of a cross-sectional structure of a substrate W after processing in step ST2. Figure 4 , the modified metal-containing film MF is shown as a metal-containing film MFa (MF1a, MF2a).

[0086] When the first process gas includes a fluorine-containing gas, the metal-containing film MFa can be fluorinated by the fluorine active species in the first plasma. That is, the fluorine content of the first region MF1a and the second region MF2a after the modification process can be increased compared with the first region MF1 and the second region MF2 before the modification process. As a result, the content ratio of other components (such as oxygen, carbon or tin, etc.) contained before the modification process can be reduced. The surface of the first region MF1a after the modification process can be solidified compared with the surface of the second region MF2a.

[0087] When the first process gas includes an oxygen-containing gas, the metal-containing film MFa can be oxidized by oxygen active species in the first plasma. The oxygen content of the first region MF1a and the second region MF2a after the modification process can be increased compared with the first region MF1 and the second region MF2 before the modification process. As a result, the content ratio of other components (such as carbon or tin, etc.) contained before the modification process can be reduced. The surface of the first region MF1a after the modification process can be solidified compared with the surface of the second region MF2a.

[0088] As described above, the metal-containing film MF before the modification process is a "negative" film. That is, the first region MF1 has a higher etching resistance to the plasma used in the development process than the second region MF2. In contrast, the metal-containing film MFa after the modification process becomes a "positive" film. That is, the second region MF2a has a higher etching resistance than the first region MF1a. Thus, for example, when the modified metal-containing film MFa is exposed to the second plasma used in the development process of step ST3, the first region MF1a is selectively etched and removed relative to the second region MF2a.

[0089] (Step ST3: Development of Metal-Containing Film)

[0090] In step ST3, the metal-containing film MFa is developed. First, a second process gas is supplied from the gas supply unit 30 into the plasma processing chamber 10s. Next, microwaves are radiated from the microwave plasma source 20 into the plasma processing chamber 10s. Thus, a second plasma is generated from the second process gas. At this time, a bias signal can be supplied to the lower electrode of the substrate support unit 11 to generate a bias potential between the second plasma and the substrate W. Active species such as ions and free radicals in the second plasma are attracted to the substrate W, and the metal-containing film MFa is developed using the active species.

[0091] The second process gas may be selected corresponding to the first process gas. When the first process gas includes a fluorine-containing gas, the second process gas includes a chlorine-containing gas. The chlorine-containing gas may be, for example, BCl3 gas or Cl2 gas.

[0092] When the first process gas includes oxygen, the second process gas may include a hydrogen-containing gas (e.g., H2 gas), a nitrogen-containing gas (e.g., N2 gas), and a chlorine-containing gas (e.g., Cl2 gas). The supply of these gases may not be simultaneous. For example, as the second process gas, a hydrogen-containing gas, a nitrogen-containing gas, and a chlorine-containing gas may be supplied alternately. That is, the process of supplying a hydrogen-containing gas and a nitrogen-containing gas as the second process gas to generate a second plasma and the process of supplying a chlorine-containing gas as the second process gas to generate a second plasma may be repeated alternately.

[0093] Figure 51 is a diagram showing an example of a cross-sectional structure of the substrate W after the process in step ST3. As described above, the second region MF2a has higher etching resistance to the second plasma used in the development process than the first region MF1a. Figure 5 As shown, the first region MF1a is selectively etched away with respect to the second region MF2a by a development process, thereby forming an opening OP in the metal-containing film MFa.

[0094] The opening OP is defined by the side of the second region MF2a. The opening OP is a space on the etching target film EF surrounded by the side. The opening OP has a shape corresponding to the first region MF1a when viewed from above the substrate W (which is a shape corresponding to the opening of the exposure mask for exposing the metal-containing film MF). The shape can be, for example, a circle, an ellipse, a rectangle, a line, or a combination of one or more thereof. A plurality of openings OP can be formed in the metal-containing film MFa. The plurality of openings OP each have a hole shape and can form an array pattern arranged at a certain interval. In addition, the plurality of openings OP each have a line shape and can be arranged at a certain interval to form a pattern of lines and intervals.

[0095] (Step ST4: Etching of Etching Target Film)

[0096] In step ST4, the etching target film EF is etched. First, a third processing gas is supplied from the gas supply unit 30 into the plasma processing chamber 10s. The third processing gas can be selected so that the etching target film EF is etched with a sufficient selectivity relative to the metal-containing film MFa. Next, microwaves are radiated from the microwave plasma source 20 into the plasma processing chamber 10s. Thus, a third plasma is generated by the third processing gas. At this time, a bias signal can be supplied to the lower electrode of the substrate support unit 11 to generate a bias potential between the third plasma and the substrate W. Active species such as ions and free radicals in the third plasma are attracted to the substrate W, and the etching target film EF is etched by the active species.

[0097] Figure 6 FIG. 1 is a diagram showing an example of a cross-sectional structure of a substrate W after processing in step ST4. In step ST4, the metal-containing film MFa is used as a mask to etch the etching target film EF. Figure 6 As shown, in step ST4 , the recess RC is formed in the etching target film EF based on the shape of the opening OP including the metal film MFa.

[0098] According to the present processing method, since the "negative" metal-containing film MF can be formed into a "positive" film by the modification process, a pattern consisting of the second region MF2a not exposed on the metal-containing film MF can be formed by the development process. Therefore, according to the present processing method, a fine pattern (for example, a fine Hall array pattern) that is difficult to achieve in a conventional "negative" photoresist film can be formed on the metal-containing film MF.

[0099] <Example>

[0100] Next, examples of the present treatment method are described. The present disclosure is not limited in any way by the following examples.

[0101] (Example 1)

[0102] In Embodiment 1, the present processing method is applied to a substrate W using a plasma processing apparatus 1. The metal-containing film MF on the substrate W is formed by exposing a photoresist film containing tin to EUV. The first processing gas used for the modification processing of step ST2 includes CF4 gas. The second processing gas used for the development processing of step ST3 includes BCl3 gas and Cl2 gas.

[0103] (Reference Example 1)

[0104] In Reference Example 1, the metal-containing film MF similar to that of Example 1 was subjected to development treatment under the same conditions as those of Step ST3 of Example 1 without performing the modification treatment in Step ST2 .

[0105] The etching rates of the metal-containing film MF of Example 1 and Reference Example 1 during the development process are shown in Table 1. "ER1" is the etching rate of the exposed first region, and "ER2" is the etching rate of the unexposed second region.

[0106] Table 1

[0107] Example 1 Reference Example 1 ER1(nm / min) 116 159 ER2(nm / min) 43 226

[0108] As shown in Table 1, in Example 1, the etching rate of the first region in the development process is greater than the etching rate of the second region. That is, the second region has a higher etching resistance to the plasma used in the development process than the first region. In contrast, in Reference Example 1, the etching rate of the second region in the development process is greater than the etching rate of the first region. That is, the first region has a higher etching resistance to the plasma used in the development process than the second region.

[0109] (Example 2)

[0110] In Example 2, the present processing method is applied to a substrate W using a plasma processing apparatus 1. The metal-containing film MF is formed on the substrate W in the same manner as in Example 1. The first processing gas used for the modification processing in step ST2 includes Cl2 gas and O2 gas. In the development processing in step ST3, N2 gas and H2 gas are alternately supplied as the second processing gas; and Cl2 gas.

[0111] (Reference Example 2)

[0112] In Reference Example 2, the modification treatment in step ST2 is not performed, and the metal-containing film MF similar to that in Example 2 is subjected to development treatment under the same conditions as step ST3 in Example 2.

[0113] The etching rates of the metal-containing film MF of Example 2 and Reference Example 2 during the development process are shown in Table 2. "ER1" is the etching rate of the exposed first region, and "ER2" is the etching rate of the unexposed second region.

[0114] Table 2

[0115] Example 2 Reference Example 2 ER1(nm / min) 81 150 ER2(nm / min) 37 219

[0116] As shown in Table 2, in Example 2, the etching rate of the first region in the development process is greater than the etching rate of the second region. That is, the second region has a higher etching resistance to the plasma used in the development process than the first region. In contrast, in Reference Example 2, the etching rate of the second region in the development process is greater than the etching rate of the first region. That is, the first region has a higher etching resistance to the plasma used in the development process than the second region.

[0117] The processing method may be modified in various ways without departing from the scope and spirit of the present disclosure. For example, the processing method may be performed using a substrate processing device using any plasma source, such as an inductively coupled plasma processing device, a capacitively coupled plasma processing device, etc., in addition to the plasma processing device 1 using a microwave plasma source.

[0118] The embodiments of the present disclosure also include the following aspects.

[0119] (Note 1)

[0120] A plasma processing method is a plasma processing method performed in a plasma processing device having a chamber, comprising:

[0121] (a) preparing a substrate having an etching target film and a metal-containing film provided on the etching target film on a substrate support portion in a chamber, wherein the metal-containing film has an exposed first region and an unexposed second region;

[0122] (b) a step of modifying the metal-containing film using a first plasma generated from a first process gas including either a fluorine-containing gas or an oxygen-containing gas; and

[0123] (c) A step of removing the first region of the modified metal-containing film selectively with respect to the second region using a second plasma generated from a second process gas.

[0124] (Note 2)

[0125] The plasma processing method according to Supplement 1, wherein, through the modification in the step (b), the etching resistance of the second region to the second plasma is greater than the etching resistance of the first region to the second plasma.

[0126] (Note 3)

[0127] The plasma processing method according to Supplementary Note 1 or Supplementary Note 2, wherein in the step (c), the first region is removed to expose the etching target film.

[0128] (Note 4)

[0129] The plasma processing method according to any one of Supplementary Notes 1 to 3, wherein the metal-containing film includes tin or titanium.

[0130] (Note 5)

[0131] The plasma processing method according to Supplementary Note 4, wherein the metal-containing film contains an organic substance.

[0132] (Note 6)

[0133] The plasma processing method according to any one of Notes 1 to 5, wherein the first processing gas includes at least one gas selected from the group consisting of fluorocarbon gas, hydrofluorocarbon gas, NF3 gas and SF6 gas.

[0134] (Note 7)

[0135] The plasma processing method according to Note 6, wherein the second processing gas includes a chlorine-containing gas.

[0136] (Note 8)

[0137] According to the plasma processing method described in Note 7, the chlorine-containing gas is BCl3 gas or Cl2 gas.

[0138] (Note 9)

[0139] The plasma processing method according to any one of Supplementary Notes 1 to 5, wherein the first processing gas includes at least one gas selected from the group consisting of O2 gas, CO gas and CO2 gas.

[0140] (Note 10)

[0141] According to the plasma processing method described in Note 9, the first processing gas also includes a chlorine-containing gas.

[0142] (Note 11)

[0143] The plasma processing method according to Note 10, wherein the chlorine-containing gas is at least one gas selected from the group consisting of Cl2 gas, BCl3 gas and SiCl4 gas.

[0144] (Note 12)

[0145] A plasma processing method according to any one of Notes 9 to 12, wherein, for the process (c), generating the second plasma by using a gas including a hydrogen-containing gas and a nitrogen-containing gas as the second processing gas and generating the second plasma by using a gas including a chlorine-containing gas as the second processing gas are repeated alternately.

[0146] (Note 13)

[0147] The plasma processing method according to any one of Supplementary Notes 1 to 12, wherein the etching target film is a silicon-containing film or a carbon-containing film.

[0148] (Note 14)

[0149] The plasma processing method according to any one of Supplementary Notes 1 to 13, further comprising, after the step (c), a step (d) of etching the etching target film using the metal-containing film as a mask.

[0150] (Note 15)

[0151] The plasma processing method according to Supplementary Note 14, wherein the steps (a) to (d) are performed in the same chamber.

[0152] (Note 16)

[0153] A plasma processing method according to any one of Notes 1 to 15, wherein the metal-containing film includes a metal-containing photoresist film, the first region is an exposed region in the metal-containing photoresist film, and the second region is an unexposed region in the metal-containing photoresist.

[0154] (Note 17)

[0155] The plasma processing method according to Supplement 16, wherein the first region is exposed by EUV.

[0156] (Note 18)

[0157] A plasma processing system comprises a chamber, a substrate support part and a control part arranged in the chamber,

[0158] The control unit performs the following control, which includes:

[0159] (a) preparing a substrate having an etching target film and a metal-containing film provided on the etching target film on the substrate support portion, wherein the metal-containing film has an exposed first region and an unexposed second region;

[0160] (b) controlling the modification of the metal-containing film using a first plasma generated from a first process gas including any one of a fluorine-containing gas and an oxygen-containing gas; and

[0161] (c) controlling the selective removal of the first region of the modified metal-containing film relative to the second region using a second plasma generated from a second process gas.

[0162] (Note 19)

[0163] A device manufacturing method is performed in a plasma processing device having a chamber, and comprises:

[0164] (a) preparing a substrate having an etching target film and a metal-containing film provided on the etching target film on a substrate support portion in a chamber, wherein the metal-containing film has an exposed first region and an unexposed second region;

[0165] (b) a step of modifying the metal-containing film using a first plasma generated from a first process gas including either a fluorine-containing gas or an oxygen-containing gas; and

[0166] (c) A step of removing the first region of the modified metal-containing film selectively with respect to the second region using a second plasma generated from a second process gas.

[0167] (Note 20)

[0168] A program that causes a computer of a plasma processing system including a chamber and a plasma generating unit of a substrate supporting unit disposed in the chamber to execute the following control:

[0169] (a) preparing a substrate having an etching target film and a metal-containing film provided on the etching target film on the substrate support portion, wherein the metal-containing film has an exposed first region and an unexposed second region;

[0170] (b) controlling the modification of the metal-containing film using a first plasma generated from a first process gas including any one of a fluorine-containing gas and an oxygen-containing gas; and

[0171] (c) controlling the selective removal of the first region of the modified metal-containing film relative to the second region using a second plasma generated from a second process gas.

[0172] (Note 21)

[0173] A storage medium storing the program according to Appendix 20.

Claims

1. A plasma processing method, the plasma processing method being performed in a plasma processing device having a chamber, comprising: (a) preparing a substrate having an etching target film and a metal-containing film provided on the etching target film on a substrate support portion in a chamber, wherein the metal-containing film has an exposed first region and an unexposed second region; (b) a step of modifying the metal-containing film using a first plasma generated from a first process gas including either a fluorine-containing gas or an oxygen-containing gas; and (c) A step of removing the first region of the modified metal-containing film selectively with respect to the second region using a second plasma generated from a second process gas.

2. The plasma processing method according to claim 1, wherein: Through the modification in the step (b), the etching resistance of the second region to the second plasma is greater than the etching resistance of the first region to the second plasma.

3. The plasma processing method according to claim 2, wherein: In the step (c), the first region is removed to expose the etching target film.

4. The plasma processing method according to any one of claims 1 to 3, wherein: The metal-containing film includes tin or titanium.

5. The plasma processing method according to claim 4, wherein: The metal-containing film includes an organic substance.

6. The plasma processing method according to claim 1, wherein: The first process gas includes at least one gas selected from the group consisting of fluorocarbon gas, hydrofluorocarbon gas, NF3 gas and SF6 gas.

7. The plasma processing method according to claim 6, wherein: The second process gas includes a chlorine-containing gas.

8. The plasma processing method according to claim 7, wherein: The chlorine-containing gas is BCl3 gas or Cl2 gas.

9. The plasma processing method according to claim 1, wherein: The first process gas includes at least one gas selected from the group consisting of O 2 gas, CO gas, and CO 2 gas.

10. The plasma processing method according to claim 9, wherein: The first process gas also includes a chlorine-containing gas.

11. The plasma processing method according to claim 10, wherein: The chlorine-containing gas is at least one gas selected from the group consisting of Cl2 gas, BCl3 gas and SiCl4 gas.

12. The plasma processing method according to claim 9, wherein: In the step (c), the second plasma is generated by using a gas including a hydrogen-containing gas and a nitrogen-containing gas as the second process gas and the second plasma is generated by using a gas including a chlorine-containing gas as the second process gas.

13. The plasma processing method according to claim 1, wherein: The etching target film is a silicon-containing film or a carbon-containing film.

14. The plasma processing method according to claim 1, wherein: After the step (c), the method further includes the step (d) of etching the etching target film using the metal-containing film as a mask.

15. The plasma processing method according to claim 14, wherein: The steps (a) to (d) are performed in the same chamber.

16. The plasma processing method according to claim 1, wherein: The metal-containing film includes a metal-containing photoresist film, the first region is an exposed region in the metal-containing photoresist film, and the second region is an unexposed region in the metal-containing photoresist film.

17. The plasma processing method according to claim 16, wherein: The first region is exposed by EUV.

18. A plasma processing system comprising a chamber, a substrate support portion disposed in the chamber, and a control portion, The control unit performs the following control, which includes: (a) preparing a substrate having an etching target film and a metal-containing film provided on the etching target film on the substrate support portion, wherein the metal-containing film has an exposed first region and an unexposed second region; (b) controlling the modification of the metal-containing film using a first plasma generated from a first process gas including any one of a fluorine-containing gas and an oxygen-containing gas; and (c) controlling the selective removal of the first region of the modified metal-containing film relative to the second region using a second plasma generated from a second process gas.

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