Plasma processing apparatus

Abstract

To provide a technique for increasing an etching rate in plasma etching of a silicon-containing film.SOLUTION: The disclosed etching method includes a step (a) of preparing a substrate in a chamber of a plasma processing apparatus. The substrate includes a silicon-containing film. The etching method further includes a step (b) of etching the silicon-containing film with chemical species from plasma formed from the processing gas in the chamber. The processing gas includes a phosphorus-containing gas, a fluorine-containing gas, and a hydrogen-containing gas. The hydrogen-containing gas contains at least one selected from the group consisting of hydrogen fluoride, H2, ammonia, and hydrocarbons.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY Exemplary embodiments of the present disclosure relate to etching methods, process gases, and plasma processing apparatuses. [Background technology]

[0002] In the manufacture of electronic devices, plasma etching of silicon-containing films on substrates is performed. In plasma etching, the silicon-containing film is etched using plasma generated from a process gas. U.S. Patent Application Publication No. 2016 / 0343580 discloses a process gas containing a fluorocarbon gas as a process gas used in plasma etching of silicon-containing films. JP 2016-39310 A discloses a process gas containing a hydrocarbon gas and a hydrofluorocarbon gas as a process gas used in plasma etching of silicon-containing films. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2016 / 0343580 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-39310 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques for increasing the etch rate in plasma etching of silicon-containing films. [Means for solving the problem]

[0005] In one exemplary embodiment, an etching method is provided. The etching method includes step (a) of providing a substrate in a chamber of a plasma processing apparatus. The substrate includes a silicon-containing film. The etching method further includes step (b) of etching the silicon-containing film with chemical species from a plasma formed in the chamber from a processing gas. The processing gas includes a phosphorus-containing gas, a fluorine-containing gas, and a hydrogen-containing gas. The hydrogen-containing gas contains at least one selected from the group consisting of hydrogen fluoride, H2, ammonia, and a hydrocarbon. [Effects of the Invention]

[0006] According to one exemplary embodiment, it is possible to increase the etching rate in plasma etching of silicon-containing films. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a flow diagram of an etching method according to an exemplary embodiment. [Figure 2] 2 is a partially enlarged cross-sectional view of an example substrate to which the etching method shown in FIG. 1 can be applied. [Figure 3] 1 is a diagram illustrating a schematic diagram of a plasma processing apparatus according to an exemplary embodiment; [Figure 4] FIG. 4(a) is a partially enlarged cross-sectional view of an example substrate to which the etching method shown in FIG. 1 is applied, and FIG. 4(b) is a partially enlarged cross-sectional view of an example substrate etched by plasma formed from a processing gas that does not contain phosphorus. [Figure 5] 4 is an example timing chart for an etching method according to an exemplary embodiment. [Figure 6] 6(a) and 6(b) are diagrams showing the results of XPS analysis of the protective film PF formed in an experimental example in which the silicon oxide film and the silicon nitride film were etched in the process STP, respectively. [Figure 7] 10 is a timing chart of another example of an etching method according to an exemplary embodiment. [Figure 8]10 is a graph showing the relationship between the flow rate of PF3 gas in the processing gas and the etching rate of a silicon oxide film, obtained in a first experiment. [Figure 9] 10 is a graph showing the relationship between the flow rate of PF3 gas in the processing gas and the maximum width of an opening formed in a silicon oxide film, obtained in a first experiment. [Figure 10] 10 is a graph showing the relationship between the flow rate of PF3 gas in the processing gas and the selectivity, obtained in a first experiment. [Figure 11] 10 is a graph showing the relationship between the flow rate of PF3 gas and the etching rate of a silicon-containing film, the etching rate of a mask, and the selectivity, which was obtained in a second experiment. [Figure 12] 4 is a flow diagram of an etching method according to another exemplary embodiment. [Figure 13] 13 is a partially enlarged cross-sectional view of an example of a substrate to which the etching method shown in FIG. 12 is applied. [Figure 14] 13 is a partially enlarged cross-sectional view of an example of a substrate to which the etching method shown in FIG. 12 is applied. [Figure 15] 10 is a timing chart of an example of an etching method according to another exemplary embodiment. [Figure 16] 10 is a graph showing the results of the seventh experiment. [Figure 17] 10 is a graph showing the results of the eighth to eleventh experiments. [Figure 18] FIG. 18(a) is a graph showing the results of the twelfth experiment, and FIG. 18(b) is a graph showing the results of the thirteenth experiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Various exemplary embodiments are described below.

[0009] In one exemplary embodiment, an etching method is provided. The etching method includes step (a) of providing a substrate in a chamber of a plasma processing apparatus. The substrate includes a silicon-containing film. The etching method further includes step (b) of etching the silicon-containing film with chemical species from a plasma formed in the chamber from a processing gas. The processing gas includes a phosphorus-containing gas, a fluorine-containing gas, and a hydrogen-containing gas. The hydrogen-containing gas contains at least one selected from the group consisting of hydrogen fluoride, H2, ammonia, and a hydrocarbon.

[0010] In one exemplary embodiment, the process gas may further include a halogen-containing gas containing a halogen element other than fluorine.

[0011] In another exemplary embodiment, an etching method is provided. The etching method includes step (a) of providing a substrate in a chamber of a plasma processing apparatus. The substrate includes a silicon-containing film. The etching method further includes step (b) of etching the silicon-containing film with chemical species from a plasma formed in the chamber from a processing gas. The processing gas includes a phosphorus-containing gas, a fluorine-containing gas, a hydrofluorocarbon gas, and a halogen-containing gas. The halogen-containing gas contains a halogen element other than fluorine.

[0012] In one exemplary embodiment, the fluorine-containing gas may include at least one gas selected from the group consisting of a fluorocarbon gas and a carbon-free fluorine-containing gas, and the carbon-free fluorine-containing gas may be nitrogen trifluoride gas or sulfur hexafluoride gas.

[0013] In one exemplary embodiment, the halogen-containing gas may be Cl2 gas and / or HBr gas.

[0014] In one exemplary embodiment, the flow rate ratio of the second gas to the first gas in the process gas may be greater than 0 and less than or equal to 0.5. The first gas is all gases contained in the process gas except for the phosphorus-containing gas. The second gas is the phosphorus-containing gas. The flow rate ratio may be greater than or equal to 0.075 and less than or equal to 0.3.

[0015] In one exemplary embodiment, the etching method may further include a step of forming a protective film containing a combination of phosphorus and oxygen contained in the processing gas on a sidewall surface that defines the opening formed by etching.

[0016] In one exemplary embodiment, step (b) may include periodically applying a pulsed electric bias to a lower electrode of a substrate support that supports the substrate when plasma is present in the chamber. The electric bias may be a high-frequency bias power or a negative-polarity DC voltage pulse. The frequency defining the period during which the pulsed electric bias is applied to the lower electrode may be 5 Hz or more and 100 kHz or less.

[0017] In one exemplary embodiment, the etching method may further include, before step (b), setting the temperature of the substrate support to 0° C. or less.

[0018] In yet another exemplary embodiment, an etching method is provided. The etching method includes providing a substrate in a chamber of a plasma processing apparatus. The substrate has a silicon-containing film and a mask. The etching method includes generating a plasma in the chamber from a process gas, the process gas including hydrogen fluoride gas, a phosphorus-containing gas, and a carbon-containing gas, to etch the silicon-containing film.

[0019] In one exemplary embodiment, the flow rate of the hydrogen fluoride gas may be the largest among the flow rates of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas.

[0020] In one exemplary embodiment, the process gas may further include a noble gas. Of the flow rates of all gases in the process gas except for the noble gas, the flow rate of the hydrogen fluoride gas may be the largest.

[0021] In one exemplary embodiment, the temperature of the substrate support that supports the substrate may be set to a temperature of 0° C. or lower or a temperature of −40° C. or lower in step (b).

[0022] In one exemplary embodiment, the phosphorus-containing gas may contain a halogen element. The halogen element in the phosphorus-containing gas may be a halogen element other than fluorine.

[0023] In one exemplary embodiment, the ratio of the flow rate of the phosphorus-containing gas to the total flow rate of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas may be 2% or more.

[0024] In one exemplary embodiment, the process gas may further include a halogen-containing gas that does not contain fluorine, and the proportion of the flow rate of the halogen-containing gas in the total flow rate of the hydrogen fluoride gas, the phosphorus-containing gas, the carbon-containing gas, and the halogen-containing gas may be greater than 0% and less than or equal to 10%.

[0025] In one exemplary embodiment, the silicon-containing film may include a silicon oxide film. The silicon-containing film may further include a silicon nitride film.

[0026] In another exemplary embodiment, a process gas for plasma etching of silicon oxide films is provided, the process gas including hydrogen fluoride gas, a phosphorus-containing gas, and a carbon-containing gas.

[0027] In one exemplary embodiment, the flow rate of the hydrogen fluoride gas may be the largest among the flow rates of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas.

[0028] In one exemplary embodiment, the process gas may further include a noble gas, and the flow rate of hydrogen fluoride gas may be the largest among the flow rates of all gases in the process gas except for the noble gas.

[0029] In one exemplary embodiment, the phosphorus-containing gas may contain a halogen element, which may be a halogen element other than fluorine.

[0030] In one exemplary embodiment, the ratio of the flow rate of the phosphorus-containing gas to the total flow rate of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas may be 2% or more.

[0031] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0032] 1 is a flow diagram of an etching method according to one exemplary embodiment. The etching method shown in FIG. 1 (hereinafter referred to as "Method MT") is applied to a substrate having a silicon-containing film. In Method MT, the silicon-containing film is etched.

[0033] Fig. 2 is a partially enlarged cross-sectional view of an example substrate to which the etching method shown in Fig. 1 can be applied. The substrate W shown in Fig. 2 can be used in the manufacture of devices such as DRAM and 3D-NAND. The substrate W has a silicon-containing film SF. The substrate W may further have an underlayer region UR. The silicon-containing film SF can be provided on the underlayer region UR.

[0034] The silicon-containing film SF may be a silicon-containing dielectric film. The silicon-containing dielectric film may include a silicon oxide film or a silicon nitride film. The silicon-containing dielectric film may be a film containing other film types as long as it contains silicon. The silicon-containing film SF may also include a silicon film (e.g., a polycrystalline silicon film). The silicon-containing film SF may also include at least one of a silicon nitride film, a polycrystalline silicon film, a carbon-containing silicon film, and a low-k film. The carbon-containing silicon film may include a SiC film and / or a SiOC film. The low-k film contains silicon and may be used as an interlayer insulating film. The silicon-containing film SF may also include two or more silicon-containing films having different film types. The two or more silicon-containing films may include a silicon oxide film and a silicon nitride film. The silicon-containing film SF may be, for example, a multilayer film including one or more silicon oxide films and one or more silicon nitride films stacked alternately. The silicon-containing film SF may also be a multilayer film including multiple silicon oxide films and multiple silicon nitride films stacked alternately. Alternatively, the two or more silicon-containing films may include a silicon oxide film and a silicon film. The silicon-containing film SF may be, for example, a multilayer film including one or more silicon oxide films and one or more silicon films that are alternately stacked. The silicon-containing film SF may be a multilayer film including multiple silicon oxide films and multiple polycrystalline silicon films that are alternately stacked. Alternatively, the two or more silicon-containing films may include a silicon oxide film, a silicon nitride film, and a silicon film.

[0035] The substrate W may further include a mask MK. The mask MK is provided on the silicon-containing film SF. The mask MK is formed of a material having an etching rate lower than that of the silicon-containing film SF in step ST2. The mask MK may be formed of an organic material. That is, the mask MK may contain carbon. The mask MK may be formed of, for example, an amorphous carbon film, a photoresist film, or a spin-on carbon film (SOC film). Alternatively, the mask MK may be formed of a silicon-containing film such as a silicon-containing anti-reflective film. Alternatively, the mask MK may be a metal-containing mask formed of a metal-containing material such as titanium nitride, tungsten, or tungsten carbide. The mask MK may have a thickness of 3 μm or more.

[0036] The mask MK is patterned. That is, the mask MK has a pattern to be transferred to the silicon-containing film SF in step ST2. When the pattern of the mask MK is transferred to the silicon-containing film SF, an opening (recess) such as a hole or a trench is formed in the silicon-containing film SF. The aspect ratio of the opening formed in the silicon-containing film SF in step ST2 may be 20 or more, 30 or more, 40 or more, or 50 or more. The mask MK may have a line-and-space pattern.

[0037] In the method MT, a plasma processing apparatus is used to etch the silicon-containing film SF. FIG. 3 is a diagram schematically illustrating a plasma processing apparatus according to an exemplary embodiment. The plasma processing apparatus 1 illustrated in FIG. 3 includes a chamber 10. The chamber 10 provides an internal space 10s therein. The chamber 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The chamber body 12 is formed of, for example, aluminum. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The corrosion-resistant film may be formed of a ceramic such as aluminum oxide or yttrium oxide.

[0038] A passage 12p is formed in the sidewall of the chamber body 12. The substrate W is transferred between the internal space 10s and the outside of the chamber 10 through the passage 12p. The passage 12p is opened and closed by a gate valve 12g. The gate valve 12g is provided along the sidewall of the chamber body 12.

[0039] A support 13 is provided on the bottom of the chamber body 12. The support 13 is made of an insulating material. The support 13 has a generally cylindrical shape. The support 13 extends upward from the bottom of the chamber body 12 within the internal space 10s. The support 13 supports a substrate support 14. The substrate support 14 is configured to support a substrate W within the internal space 10s.

[0040] The substrate support 14 has a lower electrode 18 and an electrostatic chuck 20. The substrate support 14 may further have an electrode plate 16. The electrode plate 16 is made of a conductor such as aluminum and has a generally disc shape. The lower electrode 18 is provided on the electrode plate 16. The lower electrode 18 is made of a conductor such as aluminum and has a generally disc shape. The lower electrode 18 is electrically connected to the electrode plate 16.

[0041] The electrostatic chuck 20 is provided on the lower electrode 18. The substrate W is placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a main body and an electrode. The main body of the electrostatic chuck 20 has a substantially disk shape and is formed from a dielectric material. The electrode of the electrostatic chuck 20 is a film-like electrode and is provided within the main body of the electrostatic chuck 20. The electrode of the electrostatic chuck 20 is connected to a DC power supply 20p via a switch 20s. When a voltage from the DC power supply 20p is applied to the electrode of the electrostatic chuck 20, an electrostatic attractive force is generated between the electrostatic chuck 20 and the substrate W. The substrate W is attracted to the electrostatic chuck 20 by the electrostatic attractive force and is held by the electrostatic chuck 20.

[0042] An edge ring 25 is disposed on the substrate support 14. The edge ring 25 is a ring-shaped member. The edge ring 25 may be made of silicon, silicon carbide, quartz, or the like. The substrate W is disposed on the electrostatic chuck 20 and within a region surrounded by the edge ring 25.

[0043] A flow path 18f is provided inside the lower electrode 18. A heat exchange medium (e.g., a refrigerant) is supplied to the flow path 18f from a chiller unit provided outside the chamber 10 via a pipe 22a. The heat exchange medium supplied to the flow path 18f is returned to the chiller unit 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.

[0044] The plasma processing apparatus 1 is provided with a gas supply line 24. The gas supply line 24 supplies a heat transfer gas (e.g., He gas) from a heat transfer gas supply mechanism to the gap between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W.

[0045] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 14. The upper electrode 30 is supported on the upper part of the chamber body 12 via a member 32. The member 32 is made of an insulating material. The upper electrode 30 and the member 32 close the upper opening of the chamber body 12.

[0046] The upper electrode 30 may include a top plate 34 and a support 36. The bottom surface of the top plate 34 is the bottom surface on the side of the internal space 10s and defines the internal space 10s. The top plate 34 may be formed from a low-resistance conductor or semiconductor that generates little Joule heat. The top plate 34 has a plurality of gas discharge holes 34a that penetrate the top plate 34 in its thickness direction.

[0047] The support 36 detachably supports the top plate 34. The support 36 is made of a conductive material such as aluminum. A gas diffusion chamber 36a is provided inside the support 36. The support 36 has a plurality of gas holes 36b extending downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are connected to the plurality of gas discharge holes 34a, respectively. A gas inlet 36c is formed in the support 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.

[0048] A gas source group 40 is connected to the gas supply pipe 38 via a flow rate controller group 41 and a valve group 42. The flow rate controller group 41 and the valve group 42 constitute a gas supply unit. The gas supply unit may further include a gas source group 40. The gas source group 40 includes a plurality of gas sources. The plurality of gas sources include sources of process gases used in the method MT. The flow rate controller group 41 includes a plurality of flow rate controllers. Each of the plurality of flow rate controllers in the flow rate controller group 41 is a mass flow controller or a pressure-controlled flow rate controller. The valve group 42 includes a plurality of on-off valves. Each of the plurality of gas sources in the gas source group 40 is connected to the gas supply pipe 38 via a corresponding flow rate controller in the flow rate controller group 41 and a corresponding on-off valve in the valve group 42.

[0049] In the plasma processing apparatus 1, a shield 46 is detachably provided along the inner wall surface of the chamber body 12 and the outer periphery of the support part 13. The shield 46 prevents reaction by-products from adhering to the chamber body 12. The shield 46 is formed by forming a corrosion-resistant film on the surface of a base material made of, for example, aluminum. The corrosion-resistant film can be made of a ceramic such as yttrium oxide.

[0050] A baffle plate 48 is provided between the support 13 and the side wall of the chamber body 12. The baffle plate 48 is formed, for example, by forming a corrosion-resistant film (a film of yttrium oxide or the like) on the surface of a member made of aluminum. A plurality of through-holes are formed in the baffle plate 48. An exhaust port 12e is provided below the baffle plate 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 adjustment valve and a vacuum pump such as a turbomolecular pump.

[0051] The plasma processing apparatus 1 includes a high-frequency power supply 62 and a bias power supply 64. The high-frequency power supply 62 is a power supply that generates high-frequency power HF. The high-frequency power HF has a first frequency suitable for generating plasma. The first frequency is, for example, a frequency within a range of 27 MHz to 100 MHz. The high-frequency power supply 62 is connected to the lower electrode 18 via a matching box 66 and the electrode plate 16. The matching box 66 has a circuit for matching the impedance of the load side (lower electrode 18 side) of the high-frequency power supply 62 to the output impedance of the high-frequency power supply 62. The high-frequency power supply 62 may be connected to the upper electrode 30 via the matching box 66. The high-frequency power supply 62 constitutes an example of a plasma generation unit.

[0052] The bias power supply 64 is a power supply that generates an electric bias. The bias power supply 64 is electrically connected to the lower electrode 18. The electric bias has a second frequency. The second frequency is lower than the first frequency. The second frequency is, for example, a frequency within a range of 400 kHz to 13.56 MHz. When the electric bias is used together with the high frequency power HF, it is applied to the substrate support 14 (in one example, the lower electrode 18) to attract ions to the substrate W. When the electric bias is applied to the lower electrode 18, the potential of the substrate W placed on the substrate support 14 fluctuates within a period defined by the second frequency.

[0053] In one embodiment, the electrical bias may be high frequency power LF having a second frequency. When used together with the high frequency power HF, the high frequency power LF is used as high frequency bias power for attracting ions to the substrate W. A bias power supply 64 configured to generate the high frequency power LF is connected to the lower electrode 18 via a matcher 68 and the electrode plate 16. The matcher 68 has a circuit for matching the impedance of the load side (lower electrode 18 side) of the bias power supply 64 to the output impedance of the bias power supply 64.

[0054] It is also possible to generate plasma using high frequency power LF without using high frequency power HF, i.e., using only a single high frequency power. In this case, the frequency of the high frequency power LF may be a frequency greater than 13.56 MHz, for example, 40 MHz. In this case, the plasma processing apparatus 1 does not need to include the high frequency power supply 62 and the matching box 66. In this case, the bias power supply 64 constitutes an example of a plasma generating unit.

[0055] In another embodiment, the electrical bias may be a pulsed DC voltage. The pulsed DC voltage is periodically generated and applied to the lower electrode 18. The period of the pulsed DC voltage is determined by the second frequency. The period of the pulsed DC voltage includes two periods. The DC voltage in one of the two periods is a negative DC voltage. The level (i.e., absolute value) of the DC voltage in one of the two periods is higher than the level (i.e., absolute value) of the DC voltage in the other of the two periods. The DC voltage in the other period may be either negative or positive. The level of the negative DC voltage in the other period may be greater than zero or may be zero. In this embodiment, the bias power supply 64 is connected to the lower electrode 18 via a low-pass filter and the electrode plate 16. Note that the pulsed DC voltage used as the electrical bias may include a pulsed voltage having a waveform other than DC.

[0056] In one embodiment, the bias power supply 64 may apply a continuous wave of electric bias to the lower electrode 18. That is, the bias power supply 64 may continuously apply an electric bias to the lower electrode 18. The continuous wave of electric bias may be applied to the lower electrode 18 during the period when step STP or steps ST2 and ST3 of the method MT are being performed.

[0057] In another embodiment, the bias power supply 64 may apply a pulse wave of an electric bias to the lower electrode 18. The pulse wave of the electric bias may be applied periodically to the lower electrode 18. The period of the pulse wave of the electric bias is defined by a third frequency. The third frequency is lower than the second frequency. The third frequency is, for example, 1 Hz or more and 200 kHz or less. In another example, the third frequency may be 5 Hz or more and 100 kHz or less.

[0058] The period of the pulse wave of the electric bias includes two periods, i.e., an H period and an L period. The level of the electric bias during the H period (i.e., the level of the pulse of the electric bias) is higher than the level of the electric bias during the L period. That is, the pulse wave of the electric bias may be applied to the lower electrode 18 by increasing or decreasing the level of the electric bias. The level of the electric bias during the L period may be greater than zero. Alternatively, the level of the electric bias during the L period may be zero. That is, the pulse wave of the electric bias may be applied to the lower electrode 18 by alternately switching between supplying and stopping the supply of the electric bias to the lower electrode 18. Here, when the electric bias is a high-frequency power LF, the level of the electric bias is the power level of the high-frequency power LF. When the electric bias is a high-frequency power LF, the level of the high-frequency power LF in the pulse of the electric bias may be 2 kW or more. When the electric bias is a pulse wave of a negative DC voltage, the level of the electric bias is the effective absolute value of the negative DC voltage. The duty ratio of the pulse wave of the electric bias, i.e., the proportion of the H period in the cycle of the pulse wave of the electric bias, is, for example, 1% or more and 80% or less. In another example, the duty ratio of the pulse wave of the electric bias may be 5% or more and 50% or less. Alternatively, the duty ratio of the pulse wave of the electric bias may be 50% or more and 99% or less. The pulse wave of the electric bias may be applied to the lower electrode 18 to perform steps ST2 and ST3 of the method MT.

[0059] In one embodiment, the high frequency power supply 62 may supply a continuous wave of high frequency power HF. That is, the high frequency power supply 62 may supply the high frequency power HF continuously. The continuous wave of high frequency power HF may be supplied during the period when step STP or steps ST2 and ST3 of the method MT are being performed.

[0060] In another embodiment, the high frequency power supply 62 may supply a pulse wave of high frequency power HF. The pulse wave of high frequency power HF may be supplied periodically. The period of the pulse wave of high frequency power HF is defined by a fourth frequency. The fourth frequency is lower than the second frequency. In one embodiment, the fourth frequency is the same as the third frequency. The period of the pulse wave of high frequency power HF includes two periods, namely, an H period and an L period. The power level of the high frequency power HF in the H period is higher than the power level of the high frequency power HF in the L period of the two periods. The power level of the high frequency power HF in the L period may be greater than zero or may be zero.

[0061] The period of the pulse wave of the high frequency power HF may be synchronized with the period of the pulse wave of the electric bias. The H period in the period of the pulse wave of the high frequency power HF may be synchronized with the H period in the period of the pulse wave of the electric bias. Alternatively, the H period in the period of the pulse wave of the high frequency power HF may not be synchronized with the H period in the period of the pulse wave of the electric bias. The time length of the H period in the period of the pulse wave of the high frequency power HF may be the same as or different from the time length of the H period in the period of the pulse wave of the electric bias.

[0062] When plasma processing is performed in the plasma processing apparatus 1, gas is supplied from the gas supply unit to the internal space 10s. In addition, a high-frequency electric field is generated between the upper electrode 30 and the lower electrode 18 by supplying high-frequency power HF and / or an electric bias. The generated high-frequency electric field generates plasma from the gas in the internal space 10s.

[0063] The plasma processing apparatus 1 may further include 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, etc. The control unit 80 controls each unit of the plasma processing apparatus 1. The control unit 80 allows an operator to input commands and the like to manage the plasma processing apparatus 1 using the input device. The control unit 80 also allows the display device to visualize and display the operating status of the plasma processing apparatus 1. Furthermore, the storage unit stores a control program and recipe data. The control program is executed by the processor to perform various processes in the plasma processing apparatus 1. The processor executes the control program and controls each unit of the plasma processing apparatus 1 according to the recipe data.

[0064] Referring again to Figure 1, the method MT will be described below using an example in which it is applied to a substrate W shown in Figure 2 using a plasma processing apparatus 1. When the plasma processing apparatus 1 is used, the method MT can be performed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 with a control unit 80. The following description also explains how the control unit 80 controls each part of the plasma processing apparatus 1 to perform the method MT.

[0065] In the following description, in addition to FIG. 1, reference will be made to FIGS. 4(a), 4(b), and 5. FIG. 4(a) is a partially enlarged cross-sectional view of an example substrate to which the etching method shown in FIG. 1 is applied, and FIG. 4(b) is a partially enlarged cross-sectional view of an example substrate etched by plasma formed from a phosphorus-free processing gas. FIG. 5 is a timing chart of an example etching method according to an exemplary embodiment. In FIG. 5, the horizontal axis represents time. In FIG. 5, the vertical axis represents the power level of the high frequency power HF, the electrical bias level, and the supply state of the processing gas. The "L" level of the high frequency power HF indicates that the high frequency power HF is not being supplied or that the power level of the high frequency power HF is lower than the power level indicated by "H." The "L" level of the electrical bias indicates that the electrical bias is not being applied to the lower electrode 18 or that the level of the electrical bias is lower than the level indicated by "H." Furthermore, the processing gas supply status "ON" indicates that processing gas is being supplied into chamber 10, and the processing gas supply status "OFF" indicates that the supply of processing gas into chamber 10 has been stopped.

[0066] 1, the method MT begins with step ST1. In step ST1, a substrate W is prepared in a chamber 10. The substrate W is placed on an electrostatic chuck 20 in the chamber 10 and held by the electrostatic chuck 20. The substrate W may have a diameter of 300 mm.

[0067] In the method MT, step STP is then performed. In step STP, plasma processing is performed on the substrate W. In step STP, plasma is generated from a processing gas in the chamber 10. The method MT includes step ST2. Step ST2 is performed during the execution of step STP. The method MT may further include step ST3. Step ST3 is performed during the execution of step STP. Steps ST2 and ST3 may occur simultaneously or may be performed independently of each other.

[0068] In step ST2, the silicon-containing film SF is etched by chemical species from the plasma generated from the processing gas in the chamber 10 in step STP. In step ST3, a protective film PF is formed on the substrate W by chemical species from the plasma generated from the processing gas in the chamber 10 in step STP. The protective film PF is formed on a sidewall surface that defines an opening formed in the silicon-containing film SF.

[0069] The process gas used in the process STP contains a halogen element and phosphorus. The halogen element contained in the process gas may be fluorine. The process gas may contain at least one halogen-containing molecule. The process gas may contain at least one of a fluorocarbon or a hydrofluorocarbon as the at least one halogen-containing molecule. The fluorocarbon may be, for example, at least one of CF4, C3F8, C4F6, or C4F8. The hydrofluorocarbon may be, for example, at least one of CH2F2, CHF3, or CH3F. The hydrofluorocarbon may contain two or more carbon atoms. The hydrofluorocarbon may, for example, contain three carbon atoms or four carbon atoms.

[0070] The process gas may include at least one phosphorus-containing molecule. The phosphorus-containing molecule may be tetraphosphorus decoxide (PO 10The phosphorus-containing molecule may be an oxide such as tetraphosphorus octoxide (P4O8), or tetraphosphorus hexaoxide (P4O6). Tetraphosphorus decaoxide is sometimes called diphosphorus pentoxide (P2O5). The phosphorus-containing molecule may be a halide such as phosphorus trifluoride (PF3), phosphorus pentafluoride (PF5), phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), phosphorus tribromide (PBr3), phosphorus pentabromide (PBr5), or phosphorus iodide (PI3). That is, the phosphorus-containing molecule may contain fluorine as the halogen element. Alternatively, the phosphorus-containing molecule may contain a halogen element other than fluorine as the halogen element. The phosphorus-containing molecule may be a phosphoryl halide such as phosphoryl fluoride (POF3), phosphoryl chloride (POCl3), or phosphoryl bromide (POBr3). The phosphorus-containing molecule may be phosphine (PH3), calcium phosphide (e.g., Ca3P2), phosphoric acid (H3PO4), sodium phosphate (Na3PO4), hexafluorophosphate (HPF6), etc. The phosphorus-containing molecule may be fluorophosphines (H x PF y ) where the sum of x and y is 3 or 5. Examples of fluorophosphines include HPF2 and H2PF3. The process gas may contain one or more of the above-mentioned phosphorus-containing molecules as the at least one phosphorus-containing molecule. For example, the process gas may contain at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3, or PBr5 as the at least one phosphorus-containing molecule. Note that, when each phosphorus-containing molecule contained in the process gas is in a liquid or solid state, it may be vaporized by heating or the like and supplied into the chamber 10.

[0071] The process gas used in the process STP may further contain carbon and hydrogen. The process gas may contain H, hydrogen fluoride (HF), hydrocarbon (C x H y ), hydrofluorocarbons (CH x F yThe process gas may contain at least one of fluorocarbon, HCl, or NH3. The hydrocarbon may be, for example, CH4 or C3H6. Here, x and y are each a natural number. The process gas may contain a fluorocarbon or a hydrocarbon (for example, CH4) as a carbon-containing molecule. The process gas may further contain oxygen. The process gas may contain, for example, O2. Alternatively, the process gas may not contain oxygen.

[0072] In one embodiment, the process gas includes a phosphorus-containing gas, a fluorine-containing gas, and a hydrogen-containing gas. The hydrogen-containing gas includes at least one selected from the group consisting of hydrogen fluoride (HF), H2, ammonia (NH3), and a hydrocarbon. The phosphorus-containing gas includes at least one of the above-mentioned phosphorus-containing molecules. The fluorine-containing gas includes at least one gas selected from the group consisting of a fluorocarbon gas and a carbon-free fluorine-containing gas. The fluorocarbon gas is a gas containing the above-mentioned fluorocarbon. The carbon-free fluorine-containing gas is, for example, nitrogen trifluoride gas (NF3 gas) or sulfur hexafluoride gas (SF6 gas). The process gas may further include a hydrofluorocarbon gas. The hydrofluorocarbon gas is a hydrofluorocarbon gas. The process gas may further include a halogen-containing gas containing a halogen element other than fluorine. The halogen-containing gas is, for example, Cl2 gas and / or HBr gas.

[0073] An example of the process gas includes or consists essentially of a phosphorus-containing gas, a fluorocarbon gas, a hydrogen-containing gas, and an oxygen-containing gas (e.g., O2 gas). Another example of the process gas includes or consists essentially of a phosphorus-containing gas, a carbon-free fluorine-containing gas, a fluorocarbon gas, a hydrogen-containing gas, a hydrofluorocarbon gas, and a halogen-containing gas containing a halogen element other than fluorine.

[0074] In another embodiment, the process gas comprises or consists essentially of the above-mentioned phosphorus-containing gas, the above-mentioned fluorine-containing gas, the above-mentioned hydrofluorocarbon gas, and the above-mentioned halogen-containing gas containing a halogen element other than fluorine.

[0075] In one embodiment, the process gas may include a first gas and a second gas. The first gas is a gas that does not contain phosphorus. That is, the first gas is all gases included in the process gas except for the phosphorus-containing gas. The first gas may include a halogen element. The first gas may include at least one halogen-containing molecular gas described above. The first gas may further include carbon and hydrogen. The first gas may further include the hydrogen-containing molecular gas and / or the carbon-containing molecular gas described above. The first gas may further include oxygen. The first gas may include O2 gas. Alternatively, the first gas may not include oxygen. The second gas is a phosphorus-containing gas. That is, the second gas is the phosphorus-containing gas described above. The second gas may include at least one phosphorus-containing molecular gas described above.

[0076] In the processing gas used in the process STP, the flow rate ratio, which is the ratio of the flow rate of the second gas to the flow rate of the first gas, may be set to be greater than 0 and not greater than 0.5. The flow rate ratio may be set to be not less than 0.075 and not greater than 0.3. The flow rate ratio may be set to be not less than 0.1 and not greater than 0.25.

[0077] As shown in FIG. 5 , in process STP, a process gas is supplied into the chamber 10. In process STP, the gas pressure in the chamber 10 is set to a specified pressure. In process STP, the gas pressure in the chamber 10 may be set to a pressure of 5 mTorr (0.65 Pa) or more and 100 mTorr (13.3 Pa) or less. Furthermore, in process STP, a high-frequency power HF is supplied to generate plasma from the process gas in the chamber 10. As shown by the solid line in FIG. 5 , a continuous wave of the high-frequency power HF may be supplied in process STP. In process STP, a high-frequency power LF may be used instead of the high-frequency power HF. In process STP, both the high-frequency power HF and an electric bias may be supplied. As shown by the solid line in FIG. 5 , a continuous wave of the electric bias may be applied to the lower electrode 18 in process STP. The power level of the high-frequency power HF may be set to a level of 2 kW or more and 10 kW or less. When high-frequency power LF is used as the electric bias, the power level of the high-frequency power LF may be set to a level of 2 kW or more. The power level of the high frequency power LF may be set to a level of 10 kW or more.

[0078] To perform the process STP, the control unit 80 controls the gas supply unit to supply a process gas into the chamber 10. The control unit 80 also controls the exhaust unit 50 to set the gas pressure in the chamber 10 to a specified pressure. The control unit 80 also controls the high frequency power supply 62 and the bias power supply 64 to supply high frequency power HF, high frequency power LF, or high frequency power HF and an electric bias.

[0079] To perform step ST2, the control unit 80 controls the gas supply unit to supply a process gas into the chamber 10. The control unit 80 also controls the exhaust device 50 to set the gas pressure in the chamber 10 to a specified pressure. The control unit 80 also controls the high frequency power supply 62 and the bias power supply 64 to supply high frequency power HF, high frequency power LF, or high frequency power HF and an electric bias.

[0080] In one embodiment of the method MT, the temperature of the substrate W at the start of step ST2 (or step STP) may be set to a temperature of 0°C or less. Setting the temperature of the substrate W to such a temperature increases the etching rate of the silicon-containing film SF in step ST2. The control unit 80 may control the chiller unit to set the temperature of the substrate W at the start of step ST2. Note that the temperature of the substrate W during execution of step ST2 (or step STP) may be a temperature of 200°C or less. If the temperature of the substrate W during execution of step ST2 (or step STP) is a temperature of 200°C or less, the phosphorus chemical species serving as the etchant can be sufficiently supplied to the bottom of the opening formed in the silicon-containing film SF.

[0081] According to the Arrhenius rate law, which stipulates that reaction rates increase with temperature, the amount of side etching decreases at low temperatures (e.g., below 0°C). At low temperatures, the volatility (a measure of the material's tendency to volatilize) of the protective film (PO) decreases. As discussed above, due to its low volatility (chemical robustness), the effectiveness of the protective film in preventing sidewalls from being etched laterally increases at low temperatures. Furthermore, for high-aspect etching, ion energies tend to be higher, and therefore, the inventors have recognized the benefit of lower etching temperatures to enhance the effectiveness of the protective film. Therefore, in the present disclosure, a protective film with lower volatility (achieved by controlling the temperature of the substrate W to be low) is more desirable because it helps suppress sidewall etching (bowing).

[0082] In one embodiment, the method MT may further include a step STT. The step STT is performed before the step ST2 (or the step STP). The temperature of the substrate W is set to a temperature of 0° C. or less in the step STT. The temperature of the substrate W at the start of the step ST2 is set in the step STT. The control unit 80 may control the chiller unit to set the temperature of the substrate W in the step STT.

[0083] In step ST2, the silicon-containing film SF is etched by halogen species from the plasma generated from the process gas. In one embodiment, the silicon-containing film SF is etched only in a portion exposed by the mask MK (see FIG. 4(a)).

[0084] When the processing gas contains molecules containing phosphorus and a halogen element, such as PF3, as phosphorus-containing molecules, halogen species derived from such molecules contribute to etching of the silicon-containing film SF. Therefore, phosphorus-containing molecules containing phosphorus and a halogen element, such as PF3, increase the etching rate of the silicon-containing film SF in step ST2.

[0085] In step ST3, a protective film PF is formed on a sidewall surface that defines the opening formed in the silicon-containing film SF by etching in step ST2 (see FIG. 4(a)). The protective film PF is formed by chemical species from plasma generated from the process gas in the chamber 10 in step STP. Step ST3 can be performed simultaneously with step ST2. As shown in FIG. 4(a), in one embodiment, the protective film PF may be formed so that its thickness decreases along the depth direction of the opening formed in the silicon-containing film SF.

[0086] The protective film PF includes silicon and phosphorus contained in the process gas used in the process STP. In one embodiment, the protective film PF may further include carbon and / or hydrogen contained in the process gas. In one embodiment, the protective film PF may further include oxygen contained in the process gas or contained in the silicon-containing film SF. In one embodiment, the protective film PF may include a bond of phosphorus and oxygen.

[0087] Figures 6(a) and 6(b) show the results of XPS analysis of the protective film PF formed in an experimental example in which a silicon oxide film and a silicon nitride film were etched in the STP process. Figures 6(a) and 6(b) each show a P2p spectrum. The conditions for the STP process in the experimental example are as follows: <Conditions for process STP> Gas pressure in chamber 10: 100 mTorr (13.33 Pa) Processing gas: 50 sccm of PF3 gas and 150 sccm of Ar gas High frequency power HF (continuous wave): 40MHz, 4500W High frequency power LF (continuous wave): 400kHz, 7000W Substrate temperature (temperature of substrate holder before etching starts): -70°C Process STP execution period duration: 30 seconds

[0088] In an experimental example in which a silicon oxide film was etched in the process STP, the XPS analysis of the protective film PF showed Si-O bond peaks and PO bond peaks, as shown in Figure 6(a). Also, in an experimental example in which a silicon nitride film was etched in the process STP, the XPS analysis of the protective film PF showed Si-P bond peaks and PN bond peaks, as shown in Figure 6(b).

[0089] In one embodiment, the plasma of the processing gas described above includes plasma generated from hydrogen fluoride. In one embodiment, hydrogen fluoride may be the most abundant chemical species contained in the plasma generated from the processing gas. When phosphorus species generated from the phosphorus-containing gas (gas containing the above-described phosphorus-containing molecules) are present on the surface of the substrate W, adsorption of hydrogen fluoride, i.e., the etchant, to the substrate W is promoted. That is, when phosphorus species generated from the phosphorus-containing gas are present on the surface of the substrate W, the supply of the etchant to the bottom of the opening (recess) is promoted, thereby increasing the etching rate of the silicon-containing film SF.

[0090] Furthermore, if the processing gas does not contain phosphorus, the silicon-containing film SF is also etched laterally, as shown in FIG. 4B. As a result, the width of the opening formed in the silicon-containing film SF becomes wider in some places. For example, the width of the opening formed in the silicon-containing film SF becomes wider in some places near the mask MK.

[0091] On the other hand, in method MT, a protective film PF is formed on the sidewall surface that defines the opening formed in the silicon-containing film SF by etching. The silicon-containing film SF is etched while the sidewall surface is protected by this protective film PF. Therefore, according to method MT, it is possible to suppress lateral etching during plasma etching of the silicon-containing film SF.

[0092] In one embodiment, during the period in which the process STP is continued, i.e., during the period in which the plasma is generated from the processing gas in the process STP, one or more cycles each including the process ST2 and the process ST3 may be sequentially performed. In the process STP, two or more cycles may be sequentially performed.

[0093] In one embodiment, as shown by the dashed line in FIG. 5 , the above-described pulsed electric bias may be applied from the bias power supply 64 to the lower electrode 18 in step STP. That is, when plasma generated from the process gas is present in the chamber 10, the pulsed electric bias may be applied from the bias power supply 64 to the lower electrode 18. In this embodiment, etching of the silicon-containing film SF in step ST2 occurs mainly during period H in the cycle of the pulsed electric bias. Furthermore, formation of the protective film PF in step ST3 occurs mainly during period L in the cycle of the pulsed electric bias.

[0094] When the electric bias is high frequency power LF, the power level of the high frequency power LF may be set to a level of 2 kW or more during the H period within the period of the pulse wave of the electric bias. The power level of the high frequency power LF may be set to a level of 10 kW or more during the H period within the period of the pulse wave of the electric bias.

[0095] In one embodiment, as shown by the dashed line in FIG. 5 , the above-mentioned pulse wave of high frequency power HF may be supplied in step STP. During the H period within the cycle of the pulse wave of high frequency power HF, the power level of the high frequency power HF may be set to a level of 1 kW or more and 10 kW or less. As shown in FIG. 5 , the cycle of the pulse wave of high frequency power HF may be synchronized with the cycle of the pulse wave of the electric bias. As shown in FIG. 5 , the H period within the cycle of the pulse wave of high frequency power HF may be synchronized with the H period within the cycle of the pulse wave of the electric bias. Alternatively, the H period within the cycle of the pulse wave of high frequency power HF may not be synchronized with the H period within the cycle of the pulse wave of the electric bias. The time length of the H period within the cycle of the pulse wave of high frequency power HF may be the same as or different from the time length of the H period within the cycle of the pulse wave of the electric bias.

[0096] FIG. 7 is a timing chart of another example of an etching method according to an exemplary embodiment. In FIG. 7, the horizontal axis represents time. In FIG. 7, the vertical axis represents the power level of the high frequency power HF, the level of the electrical bias, the supply state of the first gas, and the supply state of the second gas. The "L" level of the high frequency power HF indicates that the high frequency power HF is not being supplied or that the power level of the high frequency power HF is lower than the power level indicated by "H." The "L" level of the electrical bias indicates that the electrical bias is not being applied to the lower electrode 18 or that the level of the electrical bias is lower than the level indicated by "H." Furthermore, the "ON" supply state of the first gas indicates that the first gas is being supplied into the chamber 10, and the "OFF" supply state of the first gas indicates that the supply of the first gas into the chamber 10 is stopped. Furthermore, the supply status of the second gas being "ON" indicates that the second gas is being supplied into the chamber 10, and the supply status of the second gas being "OFF" indicates that the supply of the second gas into the chamber 10 is stopped.

[0097] 7, in step STP, the first gas and the second gas may be alternately supplied into the chamber 10. The etching of the silicon-containing film SF in step ST2 occurs mainly during the period in which the first gas is supplied into the chamber 10. Moreover, the formation of the protective film PF in step ST3 occurs mainly during the period in which the second gas is supplied into the chamber 10.

[0098] As shown by the solid line in Fig. 7, a continuous wave of high frequency power HF may be supplied in step STP. Alternatively, a pulse wave of high frequency power HF may be supplied in step STP, similar to the pulse wave of high frequency power HF shown in Fig. 5. The pulse wave of high frequency power HF is shown by the dashed line in Fig. 7. The H period within the cycle of the pulse wave of high frequency power HF is synchronized with or partially overlaps with the period during which the first gas is supplied into chamber 10. Furthermore, the L period within the cycle of the pulse wave of high frequency power HF is synchronized with or partially overlaps with the period during which the second gas is supplied into chamber 10.

[0099] 7, a continuous wave of an electric bias may be applied to the lower electrode 18 in step STP. Alternatively, a pulse wave of an electric bias may be applied to the lower electrode 18 in step STP, similar to the pulse wave of the electric bias shown in FIG. 5. The pulse wave of the electric bias is shown by a dashed line in FIG. 7. The H period within the period of the pulse wave of the electric bias is synchronized with or partially overlaps with the period during which the first gas is supplied into the chamber 10. The L period within the period of the pulse wave of the electric bias is synchronized with or partially overlaps with the period during which the second gas is supplied into the chamber 10.

[0100] The effect of pulsing the bias power during etching is not primarily deposition, but rather the creation of a bifurcation between the etching and deposition phases. Furthermore, etching occurs primarily when bias power is applied to the bottom electrode. On the other hand, deposition occurs primarily when bias power is not applied to the bottom electrode. By applying a pulsed bias power, alternating etching and deposition phases are achieved. During the etching phase, etching occurs after a protective film is formed to protect the sidewalls of the recess (opening) from side etching. Thus, the sequential formation (deposition) of a protective film followed by etching suppresses bowing of the sidewalls while providing controlled etching that continues to increase the depth of the recess (opening). Varying the pulse duty cycle ((bias on time) / (bias on time + bias off time)) also provides a mechanism for controlling the balance between the etching and deposition phases. A longer bias off time supports the formation of a thicker protective film, providing additional protection from side etching. A longer bias on time increases the etch rate and controls the time required to reach a given etch depth.

[0101] The following describes a first experiment conducted to evaluate Method MT. In the first experiment, multiple sample substrates were prepared. Each of the sample substrates had a silicon oxide film and a mask formed on the silicon oxide film. The mask was made of an amorphous carbon film. In the first experiment, the process STP of Method MT was applied to the multiple sample substrates. The process gas used for each sample substrate contained PF3 gas at different flow rates. Other conditions for the process STP are listed below. The flow rates of PF3 gas were 0 sccm, 15 sccm, 30 sccm, 50 sccm, and 100 sccm, respectively. That is, in the first experiment, the flow rate ratios, which are the ratios of the flow rate of the second gas to the flow rate of the first gas, were 0, 0.075, 0.15, 0.25, and 0.5, respectively. <Conditions for process STP> Gas pressure in chamber 10: 25 mTorr (3.3 Pa) Process gas: 50 sccm CH4 gas, 100 sccm CF4 gas, 50 sccm O2 gas High frequency power HF (continuous wave): 40MHz, 4500W High frequency power LF (continuous wave): 400kHz, 7000W Temperature of sample substrate (temperature of substrate holder before etching starts): -30°C Process STP execution period duration: 600 seconds

[0102] In the first experiment, the maximum width of the opening formed in the silicon oxide film, the etching rate of the silicon oxide film, and the selectivity were determined for each of several sample substrates. The selectivity was calculated by dividing the etching rate of the silicon oxide film by the etching rate of the mask. The relationship between the flow rate of PF3 gas in the process gas used in the process STP and the etching rate of the silicon oxide film was then determined. The relationship between the flow rate of PF3 gas in the process gas used in the process STP and the maximum width of the opening formed in the silicon oxide film was also determined. The relationship between the flow rate of PF3 gas in the process gas used in the process STP and the selectivity was also determined. Figure 8 shows the relationship between the flow rate of PF3 gas in the process gas and the etching rate of the silicon oxide film. Figure 9 shows the relationship between the flow rate of PF3 gas in the process gas and the maximum width of the opening formed in the silicon oxide film. Figure 10 shows the relationship between the flow rate of PF3 gas in the process gas and the selectivity.

[0103] As shown in Figures 8 and 10, when the process gas contains phosphorus, i.e., when the flow rate ratio is greater than 0, the etching rate and selectivity of the silicon oxide film are increased. Also, as shown in Figure 10, when the flow rate of PF3 gas in the process gas is 15 sccm or more and 60 sccm or less, or 50 sccm or less, a significantly high selectivity is obtained. That is, when the flow rate ratio is 0.075 or more and 0.3 or less, or 0.25 or less, a significantly high selectivity is obtained. Also, as shown in Figure 8, when the flow rate of PF3 gas in the process gas is 20 sccm or more, i.e., when the flow rate ratio is 0.1 or more, the etching rate is approximately 1.5 times higher than when PF3 is not added.

[0104] 9, it was confirmed that when the processing gas contains phosphorus, it is possible to suppress the maximum width of the opening in the silicon oxide film from becoming smaller, that is, to suppress the width of the opening in the silicon oxide film from becoming wider in parts. In particular, it was confirmed that when the flow rate of PF3 gas in the processing gas is 50 sccm or more, it is possible to more significantly suppress the width of the opening in the silicon oxide film from becoming wider in parts.

[0105] In Figure 9, the horizontal axis represents the flow rate of PF3 gas, and the vertical axis represents the maximum width of the etched recess (opening). The amount of fluorine, the etchant, increases with an increase in the flow rate of PF3 gas, and an increase in the amount of etchant results in an increase in the etching rate (see Figure 8). As the flow rate of PF3 gas increases, the vertical etching rate increases. However, even with an increase in the flow rate of PF3 gas, the maximum width of the recess (opening) remains approximately constant (albeit slightly smaller) up to a flow rate of 15 sccm (7.5%). At flow rates above 15 sccm (7.5%), the maximum width of the recess (opening) decreases. Therefore, the use of a phosphorus-containing gas during etching effectively suppresses side etching (bowing).

[0106] Regarding the protective film containing P-O bonds, the protective film with P-O bonds has low volatility (i.e., is chemically strong). As recognized by the present inventors, the presence of the protective film with P-O bonds is effective in protecting the sidewalls of recesses in silicon-containing films from erosion by ions with relatively low energy. On the other hand, ions incident on the bottom of the recess (opening) have high energy and therefore remove (etch) the bottom of the recess even if a protective film is formed on the bottom of the recess. Therefore, the P-O bond protective film has a selective protection function against unwanted sidewall etching. This is because the P-O bond protective film is chemically strong enough to avoid being removed by low-energy ions impinging at a shallow angle with respect to the sidewall. On the other hand, high-energy ions impinging on the bottom of the recess by direct impact have sufficient energy to etch and remove the P-O bond protective film at the bottom of the recess. This ultimately enables etching with a higher aspect ratio while suppressing sidewall bowing.

[0107] The following describes a second experiment conducted to evaluate Method MT. In the second experiment, multiple sample substrates were prepared. Each of the sample substrates had a silicon-containing film and a mask disposed on the silicon-containing film. The silicon-containing film was a laminated film of multiple silicon oxide films and multiple silicon nitride films, alternating layers. The mask was a mask formed from an amorphous carbon film. In the second experiment, the process STP of Method MT was applied to the multiple sample substrates. The process gas used for each of the sample substrates contained PF3 gas at different flow rates. Other conditions for the process STP are shown below. The flow rates of PF3 gas were 0 sccm, 5 sccm, 20 sccm, and 30 sccm, respectively. <Conditions for process STP> Gas pressure in chamber 10: 25 mTorr (3.3 Pa) Processing gas: Fluorine-containing gas, hydrofluorocarbon gas, halogen-containing gas containing halogen elements other than fluorine, and mixed gas of PF3 gas High frequency power HF: 40MHz, 5500W High frequency power LF: 400kHz, 8400W Temperature of sample substrate (temperature of substrate holder before etching starts): -30°C

[0108] In the second experiment, the etching rate of the silicon-containing film, the etching rate of the mask, and the selectivity were determined for each of the sample substrates. The selectivity was calculated by dividing the etching rate of the silicon-containing film by the etching rate of the mask. In the second experiment, the relationship between the flow rate of the PF3 gas and the etching rate of the silicon-containing film, the etching rate of the mask, and the selectivity was determined. Figure 11 shows the relationship between the flow rate of the PF3 gas and the etching rate of the silicon-containing film, the etching rate of the mask, and the selectivity determined in the second experiment. As shown in Figure 11, the results of the second experiment confirmed that the etching rate of the silicon-containing film increased even when the flow rate of the PF3 gas added to the process gas was low. Furthermore, the selectivity was also confirmed to increase even when the flow rate of the PF3 gas added to the process gas was low.

[0109] An etching method according to another exemplary embodiment will now be described with reference to FIG. 12. FIG. 12 is a flow chart of an etching method according to another exemplary embodiment. The etching method shown in FIG. 12 (hereinafter referred to as "method MT2") is applied to a substrate having a silicon-containing film. The substrate to which method MT2 is applied is, for example, the substrate W shown in FIG. 2, and has a silicon-containing film SF. In method MT2, the silicon-containing film SF is etched. The silicon-containing film SF etched in method MT2 is the silicon-containing film SF described above in connection with method MT. The substrate W to which method MT2 is applied may further have a mask MK and an underlying region UR, as described above in connection with method MT.

[0110] In the method MT2, a plasma processing apparatus is used to etch the silicon-containing film SF. The plasma processing apparatus used in the method MT2 is, for example, the plasma processing apparatus 1 described above.

[0111] 2 using the plasma processing apparatus 1. When the plasma processing apparatus 1 is used, the method MT2 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 with the control unit 80. In the following description, the control of each part of the plasma processing apparatus 1 by the control unit 80 for executing the method MT2 will also be described.

[0112] In the following description, in addition to FIG. 12 , reference will be made to FIGS. 13 , 14 , and 15 . Each of FIGS. 13 and 14 is a partially enlarged cross-sectional view of an example substrate to which the etching method shown in FIG. 12 is applied. FIG. 15 is a timing chart of an example etching method according to another exemplary embodiment. In FIG. 15 , the horizontal axis represents time. In FIG. 15 , the vertical axis represents the power level of the high-frequency power HF, the electrical bias level, and the supply state of the process gas, similar to the vertical axis in FIG. 7 . The “L” level of the high-frequency power HF indicates that the high-frequency power HF is not being supplied or that the power level of the high-frequency power HF is lower than the power level indicated by “H.” The “L” level of the electrical bias indicates that the electrical bias is not being applied to the lower electrode 18 or that the level of the electrical bias is lower than the level indicated by “H.” Furthermore, the “ON” state of the process gas supply indicates that the process gas is being supplied into the chamber 10, and the “OFF” state of the process gas supply indicates that the supply of the process gas into the chamber 10 is stopped.

[0113] 12, the method MT2 starts with step ST21. In step ST21, a substrate W is prepared in the chamber 10 in the same manner as in step ST1 of the method MT.

[0114] In the method MT2, step ST22 is then performed. In step ST22, the silicon-containing film SF is etched by chemical species from the plasma generated from the processing gas in the chamber 10.

[0115] The process gas used in step ST22 includes a hydrogen fluoride gas, a phosphorus-containing gas, and a carbon-containing gas. The process gas may further include a rare gas. The process gas may further include a fluorine-free halogen-containing gas. The fluorine-free halogen-containing gas may contain at least one of Cl2, HBr, and BCl3, for example. The process gas may further include an oxygen-containing gas. The oxygen-containing gas may contain, for example, O2.

[0116] In the process gas used in step ST22, the phosphorus-containing gas is the phosphorus-containing gas described above in connection with the method MT. In the process gas used in step ST22, the carbon-containing gas is a hydrocarbon (C x H y ), hydrofluorocarbons (C s H t F u ), and fluorocarbons (C v F w ) where x, y, s, t, u, v, and w are each a natural number. The hydrocarbon is, for example, at least one of CH4, C3H6, etc. The hydrofluorocarbon is, for example, at least one of CH2F2, CHF3, CH3F, C2HF5, C3H2F4, etc. The fluorocarbon is, for example, at least one of CF4, C2F6, C3F6, C3F8, C4F6, C4F8, C5F8, etc. When a carbon-containing gas containing two or more carbon atoms is used, the protective effect of the sidewall surfaces defining the openings in the mask MK and the silicon-containing film SF can be greater.

[0117] In one embodiment, the flow rate of the hydrogen fluoride gas may be the highest among the flow rates of the hydrogen fluoride gas, the flow rate of the phosphorus-containing gas, and the flow rate of the carbon-containing gas in the process gas used in step ST22. When the process gas used in step ST22 contains a rare gas, the flow rate of the hydrogen fluoride gas may be the highest among the flow rates of all gases in the process gas excluding the rare gas. When the process gas does not contain a rare gas, the ratio of the flow rate of the hydrogen fluoride gas to the flow rate of the process gas excluding the rare gas may be 50% or more and less than 99%. When the process gas does not contain a rare gas, the ratio of the flow rate of the phosphorus-containing gas to the flow rate of the process gas excluding the rare gas may be 1% or more and 20% or less. In addition, in the process gas, the ratio of the flow rate of the phosphorus-containing gas to the total flow rate of the hydrogen fluoride gas, the flow rate of the phosphorus-containing gas, and the carbon-containing gas may be 2% or more. Furthermore, the ratio of the flow rate of the carbon-containing gas to the flow rate of the processing gas when the processing gas does not contain a rare gas, or to the flow rate of the processing gas excluding the rare gas when the processing gas contains a rare gas, may be greater than 0% and not more than 20%.

[0118] In one embodiment, in the processing gas used in step ST22, the proportion of the flow rate of the halogen-containing gas in the total flow rate of the hydrogen fluoride gas, the phosphorus-containing gas, the carbon-containing gas, and the halogen-containing gas may be greater than 0% and less than or equal to 10%.

[0119] To perform step ST22, the control unit 80 controls the gas supply unit to supply a processing gas into the chamber 10. The control unit 80 also controls the exhaust unit 50 to set the gas pressure in the chamber 10 to a specified pressure. The control unit 80 also controls the plasma generation unit to generate plasma from the processing gas. In the plasma processing apparatus 1, the control unit 80 controls the high frequency power supply 62 and the bias power supply 64 to supply high frequency power HF, high frequency power LF, or high frequency power HF and an electric bias.

[0120] In one embodiment, the temperature of the substrate support 14 (particularly the electrostatic chuck 20) ​​in step ST22 may be set to a temperature of 0° C. or lower or −40° C. or lower. When the temperature of the substrate W is set to such a temperature, the etching rate of the silicon-containing film SF in step ST22 increases. To set the temperature of the substrate support 14 in step ST22, the control unit 80 may control the chiller unit.

[0121] In step ST22, as shown in FIGS. 13 and 14, the silicon-containing film SF is etched by halogen species from plasma generated from the processing gas. The halogen species include fluorine species generated from hydrogen fluoride gas. Hydrogen fluoride is a small molecule, and the sputtering effect of the chemical species generated from it on the mask MK is small, so etching of the mask MK is suppressed. Therefore, the plasma generated from hydrogen fluoride gas can etch the silicon-containing film SF while suppressing etching of the mask MK. Furthermore, the plasma generated from hydrogen fluoride gas can increase the etching rate of the silicon-containing film SF. Furthermore, the chemical species generated from the carbon-containing gas protect the mask MK. The greater the number of carbon atoms in the molecules contained in the carbon-containing gas, the greater the protective effect of the mask MK. Furthermore, the plasma generated from the phosphorus-containing gas can suppress etching of the mask MK. Furthermore, when phosphorus species generated from the phosphorus-containing gas are present on the surface of the substrate W, adsorption of the chemical species generated from hydrogen fluoride, i.e., the etchant, to the substrate W is promoted. That is, when phosphorus species generated from the phosphorus-containing gas are present on the surface of the substrate W, the supply of etchant to the bottom of the opening (recess) is promoted, thereby increasing the etching rate of the silicon-containing film SF. Therefore, according to the method MT2, it is possible to improve the etching rate and etching selectivity in plasma etching of the silicon-containing film SF. Furthermore, when the phosphorus-containing gas contained in the process gas contains the above-mentioned halogen element and / or when the process gas contains the above-mentioned halogen-containing gas, the etching rate of the silicon-containing film SF is further increased. Note that, even if a hydrogen-containing gas and a fluorine-containing gas are used together with the phosphorus-containing gas instead of hydrogen fluoride gas, the same effect as that achieved by hydrogen fluoride gas can be achieved. The hydrogen-containing gas is, for example, H2 gas and / or a hydrofluorocarbon gas. The fluorine-containing gas is, for example, a fluorocarbon gas.

[0122] Furthermore, in step ST22, phosphorus species (ions and / or radicals) are supplied to the substrate W from plasma generated from a phosphorus-containing gas. The phosphorus species may form a protective film PF containing phosphorus on the surface of the substrate W, as shown in FIG. 13 . The protective film PF may further contain carbon and / or hydrogen contained in the processing gas. In one embodiment, the protective film PF may further contain oxygen contained in the processing gas or contained in the silicon-containing film SF. In one embodiment, the protective film PF may contain a bond between phosphorus and oxygen.

[0123] Instead of or in addition to forming the protective film PF, the phosphorus species may form phosphorus bonds with elements contained in the silicon-containing film SF on the sidewall surfaces that define the openings in the silicon-containing film SF. When the silicon-containing film SF includes a silicon oxide film, the phosphorus species form phosphorus-oxygen bonds on the sidewall surfaces of the silicon-containing film SF. Phosphorus is represented by a circle surrounding a "P" in FIG. 14. In step ST22, the sidewall surfaces of the silicon-containing film SF are passivated (or passivated) by the phosphorus species. That is, the sidewall surfaces of the silicon-containing film SF are passivated.

[0124] Therefore, according to the method MT2, the sidewall surface of the silicon-containing film SF is etched, and the opening of the silicon-containing film SF is prevented from expanding in the lateral direction.

[0125] If the mask MK contains carbon, the phosphorus species may form carbon-phosphorus bonds on the surface of the mask MK. The carbon-phosphorus bonds have higher bond energy than the carbon-carbon bonds in the mask MK. Therefore, according to the method MT2, the mask MK is protected during plasma etching of the silicon-containing film SF.

[0126] As shown in Fig. 15, in step ST22, a continuous wave or pulse wave of high frequency power HF may be supplied, similar to the continuous wave or pulse wave of high frequency power HF in step STP described with reference to Fig. 7. Also, in step ST22, a continuous wave or pulse wave of electric bias may be supplied, similar to the continuous wave or pulse wave of electric bias in step STP described with reference to Fig. 7.

[0127] 15 , the above-described pulsed electric bias may be applied from the bias power supply 64 to the lower electrode 18 in step ST22. In other words, when plasma generated from the process gas is present in the chamber 10, the pulsed electric bias may be applied from the bias power supply 64 to the lower electrode 18. In this embodiment, etching of the silicon-containing film SF in step ST22 occurs mainly during period H in the cycle of the pulsed electric bias. Furthermore, formation of the protective film PF and / or passivation treatment in step ST22 occurs mainly during period L in the cycle of the pulsed electric bias.

[0128] In one embodiment, as indicated by the dashed line in Fig. 15, the pulse wave of the high frequency power HF described above may be supplied in step ST22. As shown in Fig. 15, the period of the pulse wave of the high frequency power HF may be synchronized with the period of the pulse wave of the electric bias. As shown in Fig. 15, the H period in the period of the pulse wave of the high frequency power HF may be synchronized with the H period in the period of the pulse wave of the electric bias. Alternatively, the H period in the period of the pulse wave of the high frequency power HF may not be synchronized with the H period in the period of the pulse wave of the electric bias. The time length of the H period in the period of the pulse wave of the high frequency power HF may be the same as or different from the time length of the H period in the period of the pulse wave of the electric bias.

[0129] Various experiments conducted to evaluate Method MT2 are described below, but the experiments described below are not intended to limit the present disclosure.

[0130] (Experiments 3 to 6)

[0131] In Experiments 3 to 6, multiple sample substrates having the same structure as the substrate W shown in FIG. 2 were prepared. Each of the multiple sample substrates had a silicon-containing film and a mask disposed on the silicon-containing film. The silicon-containing film was a multilayer film having multiple silicon oxide films and multiple silicon nitride films alternately stacked. The mask was a mask formed of an amorphous carbon film. In Experiments 3 to 6, plasma was generated from a processing gas using plasma processing apparatus 1 to etch the silicon-containing film of the sample substrate. The processing gas used in Experiment 3 contained H gas, hydrofluorocarbon gas, fluorocarbon gas, fluorine-containing gas, and halogen-containing gas. The processing gas used in Experiment 4 contained PF gas in addition to the processing gas used in Experiment 3. The processing gas used in Experiment 5 contained hydrogen fluoride gas, fluorocarbon gas, and oxygen gas. The processing gas used in Experiment 6 contained hydrogen fluoride gas, fluorocarbon gas, and PF gas. Other conditions for each of the third to sixth experiments are shown below. <Other conditions for each of the third to sixth experiments> Gas pressure in chamber 10: 27 mTorr (3.6 Pa) High frequency power HF (continuous wave): 40MHz, 4400W High frequency power LF (continuous wave): 400kHz, 6000W Temperature of the substrate support 14: -40°C

[0132] In each of Experiments 3 to 6, the etching rate, selectivity, and maximum width of the opening (bowing CD) formed in the silicon-containing film were determined from the etching results of the silicon-containing film. The selectivity was calculated by dividing the etching rate of the silicon-containing film by the etching rate of the mask. The etching rates of the silicon-containing films in Experiments 3 to 6 were 310 nm / min, 336 nm / min, 296 nm / min, and 597 nm / min, respectively. The selectivity ratios in Experiments 3 to 6 were 3.24, 4.1, 6.52, and 7.94, respectively. The bowing CDs in Experiments 3 to 6 were 106 nm, 104 nm, 128 nm, and 104 nm, respectively. The results of Experiments 3 to 6 confirmed that Experiments 4 and 6 achieved both a higher etching rate and a higher selectivity, as well as a smaller bowing CD, compared to Experiments 3 and 5. In particular, in the sixth experiment, an etching rate about twice as high as that in the third experiment was obtained. Therefore, it was confirmed that the etching rate and etching selectivity can be improved by using a process gas containing hydrogen fluoride gas, a carbon-containing gas, and a phosphorus-containing gas in plasma etching of a silicon-containing film. Furthermore, it was confirmed that the lateral expansion of an opening in a silicon-containing film can be suppressed by using a process gas containing hydrogen fluoride gas, a carbon-containing gas, and a phosphorus-containing gas in plasma etching of a silicon-containing film.

[0133] (7th experiment)

[0134] In the seventh experiment, a plurality of sample substrates identical to the plurality of sample substrates prepared in the third to sixth experiments were prepared. In the seventh experiment, plasma was generated from a processing gas using a plasma processing apparatus 1 to etch silicon-containing films on the plurality of sample substrates. The processing gas used in the seventh experiment contained hydrogen fluoride gas and a fluorocarbon gas. In the seventh experiment, the flow rate ratio of PF3 gas in each processing gas used for the plurality of sample substrates was different from each other. Here, the flow rate ratio of PF3 gas is the ratio of the flow rate of PF3 gas to the flow rate of the processing gas. The other conditions in the seventh experiment were the same as the corresponding conditions described above for the third to sixth experiments.

[0135] In the seventh experiment, the etching rate of the silicon-containing film was determined from the etching results of each of the silicon-containing films on multiple sample substrates. The relationship between the ratio of the flow rate of PF3 gas to the etching rate of the silicon-containing film was then determined. The results are shown in Figure 16. As shown in Figure 16, it was confirmed that a high etching rate could be obtained if the ratio of the flow rate of PF3 gas to the flow rate of the processing gas was 2% or more (or 2.5% or more). In other words, it was confirmed that a high etching rate could be obtained if the flow rate of the phosphorus-containing gas was 2% or more (or 2.5% or more) relative to the flow rate of the processing gas containing hydrogen fluoride gas, carbon-containing gas, and phosphorus-containing gas.

[0136] (Experiments 8 to 11)

[0137] In each of the eighth and ninth experiments, a plurality of substrates each having a silicon oxide film were prepared. In each of the eighth and ninth experiments, plasma was generated from a processing gas using a plasma processing apparatus 1 to etch the silicon oxide films of the plurality of sample substrates. The temperatures of the substrate support 14 when the silicon oxide films of the plurality of sample substrates were etched in each of the eighth and ninth experiments were different from each other. In each of the tenth and eleventh experiments, a plurality of substrates each having a silicon nitride film were prepared. In each of the tenth and eleventh experiments, plasma was generated from a processing gas using a plasma processing apparatus 1 to etch the silicon nitride films of the plurality of sample substrates. The temperatures of the substrate support 14 when the silicon nitride films of the plurality of sample substrates were etched in each of the tenth and eleventh experiments were different from each other. The processing gas used in each of the eighth to eleventh experiments included hydrogen fluoride gas and fluorocarbon gas. The ratio of the flow rate of PF3 gas to the flow rate of the processing gas used in the eighth and tenth experiments was 2.5%. The treatment gas used in Experiments 9 and 11 did not contain PF3 gas. Other conditions for each of Experiments 8 to 11 were the same as the corresponding conditions described above for Experiments 3 to 6.

[0138] In Experiments 8 and 9, the etching rate of the silicon oxide film was determined from the etching results of the silicon oxide film of each of the sample substrates. In Experiments 10 and 11, the etching rate of the silicon nitride film was determined from the etching results of the silicon nitride film of each of the sample substrates. Figure 17 shows the relationship between the temperature of the substrate support 14 set in Experiments 8 to 11 and the resulting etching rate. In Figure 17, legends No. 8, No. 9, No. 10, and No. 11 refer to the results of Experiments 8 to 11, respectively. As shown in Figure 17, in Experiment 8, in which PF3 gas was included in the process gas, the etching rate of the silicon oxide film was confirmed to be higher than the etching rate of the silicon oxide film of Experiment 9, in which a process gas containing PF3 gas was used. Furthermore, the results of Experiment 8 confirmed that the etching rate of the silicon oxide film was further increased by setting the temperature of the substrate support 14 at 0°C or below when a process gas containing PF3 gas was used. It was also confirmed that when a processing gas containing PF3 gas is used, the etching rate of the silicon oxide film is significantly increased by setting the temperature of the substrate support 14 to -40°C or less.

[0139] (Experiments 12 and 13)

[0140] In the twelfth experiment, a silicon oxide film was etched using the plasma processing apparatus 1 by generating plasma from a process gas containing a mixture of hydrogen fluoride gas and argon gas. In the thirteenth experiment, a silicon oxide film was etched using the plasma processing apparatus 1 by generating plasma from a process gas containing a mixture of hydrogen fluoride gas, argon gas, and PF3 gas. In the twelfth and thirteenth experiments, the silicon oxide film was etched while changing the temperature of the electrostatic chuck 20. In the twelfth and thirteenth experiments, a quadrupole mass spectrometer was used to measure the amounts of hydrogen fluoride (HF) and SiF3 in the gas phase during etching of the silicon oxide film. Figures 18(a) and 18(b) show the results of the twelfth and thirteenth experiments. Figure 18(a) shows the relationship between the temperature of the electrostatic chuck 20 and the amounts of hydrogen fluoride (HF) and SiF3 during etching of the silicon oxide film in the twelfth experiment. FIG. 18(b) shows the relationship between the temperature of the electrostatic chuck 20 and the amount of hydrogen fluoride (HF) and the amount of SiF3 when etching a silicon oxide film in the thirteenth experiment.

[0141] As shown in FIG. 18(a), in the twelfth experiment, when the temperature of the electrostatic chuck 20 was approximately −60°C or lower, the amount of hydrogen fluoride (HF) used as an etchant decreased, and the amount of SiF3, a reaction product generated by etching the silicon oxide film, increased. That is, in the twelfth experiment, when the temperature of the electrostatic chuck 20 was approximately −60°C or lower, the amount of etchant used in etching the silicon oxide film increased. On the other hand, as shown in FIG. 18(b), in the thirteenth experiment, when the temperature of the electrostatic chuck 20 was 20°C or lower, the amount of hydrogen fluoride (HF) decreased, and the amount of SiF3 increased. That is, in the thirteenth experiment, when the temperature of the electrostatic chuck 20 was 20°C or lower, the amount of etchant used in etching the silicon oxide film increased. The process gas used in the thirteenth experiment differed from the process gas used in the twelfth experiment in that it contained PF3 gas. Therefore, in the thirteenth experiment, a state in which phosphorus species were present on the surface of the silicon oxide film was formed during etching of the silicon oxide film. Therefore, it can be understood that when phosphorus species were present on the surface of the silicon oxide film, adsorption of the etchant to the silicon oxide film was promoted even when the temperature of the electrostatic chuck 20 was a relatively high temperature of 20°C or less. From this, it was confirmed that when phosphorus species were present on the surface of the substrate, the supply of the etchant to the bottom of the opening (recess) was promoted, thereby increasing the etching rate of the silicon-containing film.

[0142] Experiments 14 to 16, conducted to evaluate methods MT and MT2, are described below. In Experiments 14 to 16, plasmas of different process gases were generated using the plasma processing apparatus 1. The process gases used in Experiment 14 included a hydrogen-containing gas, a fluorine-containing gas, a halogen-containing gas containing a halogen element other than fluorine, a hydrofluorocarbon gas, a fluorocarbon gas, and a hydrocarbon gas. The process gases used in Experiment 15 included a hydrofluorocarbon gas, a fluorine-containing gas, and a halogen-containing gas containing a halogen element other than fluorine. The process gases used in Experiment 16 included hydrogen fluoride gas and a fluorocarbon gas. In each of Experiments 14 to 16, a quadrupole mass spectrometer was used to measure the amount of chemical species in the plasma in the gas phase within the chamber 10. As a result, in each of Experiments 14 to 16, the chemical species with the largest amount of the measured chemical species was hydrogen fluoride. Specifically, the amounts of hydrogen fluoride measured in Experiments 14 to 16 were 35.5%, 45.5%, and 66.7%, respectively. This confirmed that the amount of hydrogen fluoride in the plasma was greatest when the processing gas contained hydrogen fluoride.

[0143] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0144] For example, the plasma processing apparatus used in each of methods MT and MT2 may be a capacitively coupled plasma processing apparatus other than the plasma processing apparatus 1. Alternatively, the plasma processing apparatus used in each of methods MT and MT2 may be an inductively coupled plasma processing apparatus, an ECR (electron cyclotron resonance) plasma processing apparatus, or a plasma processing apparatus that generates plasma using surface waves such as microwaves.

[0145] In addition to the bias power supply 64 that supplies high-frequency power LF to the lower electrode 18, the plasma processing apparatus may also include another bias power supply configured to apply pulses of negative polarity DC voltage intermittently or periodically to the lower electrode 18.

[0146] The disclosed embodiment further includes the following aspects (A1) to (A17), (B1) to (B92), and (C1) to (C19).

[0147] (A1) A step of preparing a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film; etching the silicon-containing film with chemical species from a plasma formed in the chamber from a process gas, the process gas including a halogen element and phosphorus; An etching method comprising: (A2) further comprising a step of forming a protective film on a sidewall surface defining the opening formed by the etching; The etching method according to (A1), wherein the protective film contains phosphorus contained in the processing gas. (A3) The etching method according to (A2), wherein the etching step and the protective film forming step occur simultaneously. (A4) The etching method according to any one of (A1) to (A3), wherein the processing gas contains at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3, or PBr5 as the phosphorus-containing molecule. (A5) The etching method according to any one of (A1) to (A4), wherein the processing gas further contains carbon and hydrogen. (A6) The processing gas contains H2, HF, C x H y , C.H. x F y or NH3, wherein each of x and y is a natural number. (A7) The etching method according to any one of (A1) to (A6), wherein the halogen element is fluorine. (A8) The etching method according to any one of (A1) to (A7), wherein the processing gas further contains oxygen. (A9) The etching method according to any one of (A1) to (A8), wherein the silicon-containing film is a silicon-containing dielectric film. (A10) The etching method according to any one of (A1) to (A9), wherein the silicon-containing film includes at least one of a silicon oxide film, a silicon nitride film, and a silicon film. (A11) The etching method according to any one of (A1) to (A8), wherein the silicon-containing film includes two or more silicon-containing films having different film types. (A12) The etching method according to (A11), wherein the two or more silicon-containing films include a silicon oxide film and a silicon nitride film. (A13) The etching method according to (A11), wherein the two or more silicon-containing films include a silicon oxide film and a silicon film. (A14) The etching method according to (A11), wherein the two or more silicon-containing films include a silicon oxide film, a silicon nitride film, and a silicon film. (A15) The etching method according to any one of (A1) to (A14), wherein the substrate further includes a mask provided on the silicon-containing film. (A16) The etching method according to any one of (A1) to (A15), wherein the temperature of the substrate is set to 0° C. or lower at the start of the etching step. (A17). A chamber; a substrate support configured to support a substrate within the chamber; a gas supply configured to supply a process gas for etching a silicon-containing film into the chamber, the process gas including a halogen element and phosphorus; and a radio frequency power source configured to generate radio frequency power to generate a plasma from the process gas within the chamber; A plasma processing apparatus comprising:

[0148] (B1) preparing a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film; etching the silicon-containing film with chemical species from a plasma formed in the chamber from a process gas, the process gas including a halogen element and phosphorus; Including, the process gas includes a first gas that does not contain phosphorus and a second gas that contains phosphorus; a flow rate ratio, which is a ratio of the flow rate of the second gas to the flow rate of the first gas, is greater than 0 and is equal to or less than 0.5; Etching method. (B2) The etching method according to (B1), wherein the flow ratio is 0.075 or more and 0.3 or less. (B3) The etching method according to (B1), wherein the flow ratio is 0.1 or more and 0.25 or less. (B4) The etching method according to any one of (B1) to (B3), wherein the processing gas contains PF3 as the phosphorus-containing molecules. (B5) The etching method according to any one of (B1) to (B3), wherein the processing gas contains at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3, or PBr5 as the phosphorus-containing molecule. (B6) The etching method according to any one of (B1) to (B5), wherein the processing gas further contains carbon and hydrogen. (B7) The processing gas contains H2, HF, C x H y , C.H. x F y or NH3, wherein each of x and y is a natural number. (B8) The etching method according to any one of (B1) to (B7), wherein the halogen element is fluorine. (B9) The etching method according to any one of (B1) to (B8), wherein the processing gas contains a fluorocarbon as the halogen-containing molecule. (B10) The etching method according to any one of (B1) to (B9), wherein the processing gas further contains oxygen. (B11) The etching method according to any one of (B1) to (B9), wherein the processing gas does not contain oxygen. (B12) The etching method according to any one of (B1) to (B11), wherein in the etching step, a protective film is formed on a sidewall surface that defines the opening formed by the etching. (B13) The etching method according to (B12), wherein the protective film contains a bond between phosphorus and oxygen. (B14) The etching method according to (B13), wherein the protective film further contains a bond between phosphorus and silicon. (B15) The etching method according to any one of (B1) to (B14), wherein the temperature of the substrate is set to 0° C. or lower at the start of the etching step. (B16) The etching method according to any one of (B1) to (B15), wherein in the etching step, a high-frequency bias power having a power level of 2 kW or more is supplied to a lower electrode in a substrate support that supports the substrate. (B17) The etching method according to (B16), wherein the power level is 10 kW or more. (B18) A step of preparing a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film; etching the silicon-containing film with chemical species from a plasma formed in the chamber from a process gas, the process gas including a halogen element and phosphorus; forming a protective film containing a combination of phosphorus and oxygen contained in the processing gas on a sidewall surface that defines the opening formed by the etching; An etching method comprising: (B19) The etching method according to (B18), wherein the etching step and the protective film forming step occur simultaneously. (B20) The etching method according to (B18), wherein the etching step and the protective film forming step are carried out independently of each other. (B21) The etching method according to any one of (B18) to (B20), wherein the thickness of the protective film decreases along the depth direction of the opening. (B22) To perform the etching step and the protective film forming step, a pulse wave of an electric bias is applied to a lower electrode in a substrate support that supports the substrate; The electrical bias is a high frequency bias power or a negative polarity DC voltage pulse wave. The etching method according to any one of (B18) to (B21). (B23) The etching method according to (B22), wherein the high frequency bias power applied to the lower electrode in the etching step has a power level of 2 kW or more. (B24) The etching method according to (B23), wherein the power level is 10 kW or more. (B25) The etching method according to any one of (B18) to (B24), wherein a pulse wave of high frequency power is used to generate the plasma. (B26) The etching method according to any one of (B18) to (B25), wherein the processing gas contains a first gas that does not contain phosphorus and a second gas that contains phosphorus. (B27) The etching method according to (B26), wherein the first gas and the second gas are alternately supplied to the chamber. (B28) The etching method according to (B26), wherein a flow rate ratio, which is a ratio of the flow rate of the second gas to the flow rate of the first gas, is greater than 0 and equal to or less than 0.5. (B29) The etching method according to (B28), wherein the flow rate ratio is 0.075 or more and 0.3 or less. (B30) The etching method according to (B28), wherein the flow ratio is 0.1 or more and 0.25 or less. (B31) The etching method according to any one of (B18) to (B30), wherein the protective film further contains a bond between phosphorus and silicon. (B32) The etching method according to any one of (B18) to (B31), wherein the processing gas contains PF3 as the phosphorus-containing molecules. (B33) The etching method according to any one of (B18) to (B31), wherein the processing gas contains at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3, and PBr5 as the phosphorus-containing molecules. (B34) The etching method according to any one of (B18) to (B33), wherein the processing gas further contains carbon and hydrogen. (B35) The processing gas contains H2, HF, C x H y , C.H. x F y or NH3, wherein each of x and y is a natural number. (B36) The etching method according to any one of (B18) to (B35), wherein the halogen element is fluorine. (B37) The etching method according to any one of (B18) to (B36), wherein the processing gas contains a fluorocarbon as the halogen-containing molecule. (B38) The etching method according to any one of (B18) to (B37), wherein the oxygen is provided from the silicon-containing film. (B39) The etching method according to (B38), wherein the processing gas does not contain oxygen. (B40) The etching method according to any one of (B18) to (B37), wherein the processing gas further contains oxygen. (B41) The etching method according to any one of (B18) to (B40), wherein the temperature of the substrate is set to 0° C. or lower at the start of the etching step. (B42) A step of preparing a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film; generating a plasma from a process gas containing a halogen element and phosphorus in the chamber; applying a pulsed electric bias to a lower electrode of a substrate support supporting the substrate when the plasma is present in the chamber; Including, The electrical bias is a high frequency bias power or a negative polarity DC voltage pulse wave. Etching method. (B43) The etching method according to (B42), wherein the pulse wave of the electric bias is applied to the lower electrode by alternately switching between supply and stop of the electric bias to the lower electrode. (B44) An etching method according to (B42), in which the pulse wave of the electric bias is applied to the lower electrode by increasing or decreasing the level of the electric bias. (B45) The pulse wave of the electrical bias is periodically applied to the lower electrode; The pulse wave period of the electrical bias includes two periods, a level of the pulse wave of the electrical bias in one of the two periods is higher than a level of the pulse wave of the electrical bias in the other of the two periods; a duty ratio, which is the ratio of the one period to the cycle, is 1% or more and 80% or less; The etching method according to any one of (B42) to (B44). (B46) The etching method according to (B45), wherein the frequency defining the period is 5 Hz or more and 100 kHz or less. (B47) An etching method according to (B45) or (B46), wherein the electrical bias has a power level of 2 kW or more during the one period. (B48) The etching method according to (B47), wherein the power level is 10 kW or more. (B49) The etching method according to any one of (B42) to (B48), wherein the processing gas contains a first gas that does not contain phosphorus and a second gas that contains phosphorus. (B50) The etching method according to (B49), wherein the first gas and the second gas are alternately supplied to the chamber. (B51) An etching method according to (B50), wherein the period during which the first gas is supplied at least partially overlaps with the period during which the electrical bias is applied to the lower electrode in the pulse wave cycle. (B52) The etching method according to (B49), wherein a flow rate ratio, which is a ratio of the flow rate of the second gas to the flow rate of the first gas, is greater than 0 and equal to or less than 0.5. (B53) The etching method according to (B52), wherein the flow ratio is 0.075 or more and 0.3 or less. (B54) The etching method according to (B52), wherein the flow rate ratio is 0.1 or more and 0.25 or less. (B55) The etching method according to any one of (B42) to (B54), wherein the step of applying a pulse wave of an electric bias includes a step of etching the silicon-containing film to form an opening, and a step of forming a protective film on a sidewall surface that defines the opening, and the step of forming the opening and the step of forming the protective film are performed independently of each other. (B56) The etching method according to (B55), wherein the protective film contains a bond between phosphorus and oxygen. (B57) The etching method according to (B56), wherein the protective film further contains a bond between phosphorus and silicon. (B58) The etching method according to any one of (B42) to (B57), wherein the processing gas contains PF3 as the phosphorus-containing molecules. (B59) An etching method according to any one of (B42) to (B57), wherein the processing gas contains at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3, or PBr5 as the phosphorus-containing molecule. (B60) The etching method according to any one of (B42) to (B59), wherein the processing gas further contains carbon and hydrogen. (B61) The processing gas contains H2, HF, C as the hydrogen-containing molecules. x Hy , C.H. x F y , C x H y F z or NH3, wherein each of x, y, and z is a natural number. (B62) The etching method according to any one of (B42) to (B61), wherein the halogen element is fluorine. (B63) The etching method according to any one of (B42) to (B62), wherein the processing gas contains a fluorocarbon as the halogen-containing molecule. (B64) The etching method according to any one of (B42) to (B63), wherein the processing gas further contains oxygen. (B65) The etching method according to any one of (B42) to (B63), wherein the processing gas does not contain oxygen. (B66) The etching method according to any one of (B42) to (B65), wherein the temperature of the substrate is set to 0° C. or lower at the start of the etching step. (B67) A process for preparing a substrate in a chamber of a plasma processing apparatus, the substrate including two or more silicon-containing films having different film types; setting the substrate at 0°C or less; etching the silicon-containing film with chemical species from a plasma formed in the chamber from a process gas, the process gas including PF3; An etching method comprising: (B68) The etching method according to (B67), wherein the silicon-containing film includes a silicon oxide film. (B69) An etching method according to (B67) or (B68), wherein the processing gas includes a first gas that does not contain phosphorus and a second gas that contains PF3. (B70) The etching method according to (B69), wherein a flow rate ratio, which is a ratio of the flow rate of the second gas to the flow rate of the first gas, is greater than 0 and equal to or less than 0.5. (B71) The etching method according to (B70), wherein the flow rate ratio is 0.075 or more and 0.3 or less. (B72) The etching method according to (B70), wherein the flow rate ratio is 0.1 or more and 0.25 or less. (B73) The etching method according to any one of (B67) to (B72), wherein the processing gas further contains a fluorocarbon. (B74) The etching method according to any one of (B67) to (B73), wherein the processing gas further contains carbon and hydrogen. (B75) The processing gas contains H2, HF, C x H y , C.H. x F y or NH3, wherein each of x and y is a natural number. (B76) The etching method according to any one of (B67) to (B75), wherein the processing gas further contains oxygen. (B77) The etching method according to any one of (B67) to (B75), wherein the processing gas does not contain oxygen. (B78) The etching method according to any one of (B67) to (B77), wherein in the etching step, a protective film is formed on a sidewall surface that defines the opening formed by the etching. (B79) The etching step includes etching the silicon-containing film to form an opening, and forming a protective film on a sidewall surface that defines the opening; The etching method according to any one of (B67) to (B77), wherein the step of forming the opening and the step of forming the protective film are carried out independently of each other. (B80) The etching method according to (B78) or (B79), wherein the protective film contains a bond between phosphorus and oxygen. (B81) The etching method according to (B80), wherein the protective film further contains a bond between phosphorus and silicon. (B82) An etching method according to any one of (B67) to (B81), wherein in the etching step, a high-frequency bias power having a power level of 2 kW or more is supplied to a lower electrode in a substrate support that supports the substrate. (B83) An etching method according to (B82), wherein the power level is 10 kW or more. (B84) The etching method according to any one of (B67) to (B83), wherein in the etching step, a negative DC voltage pulse wave is supplied to a lower electrode in a substrate support that supports the substrate. (B85) The etching method according to any one of (B1) to (B84), wherein the silicon-containing film is a silicon-containing dielectric film. (B86) The etching method according to any one of (B1) to (B85), wherein the silicon-containing film includes at least one of a silicon oxide film, a silicon nitride film, and a silicon film. (B87) The etching method according to any one of (B1) to (B84), wherein the silicon-containing film includes two or more silicon-containing films having different film types. (B88) The etching method according to (B87), wherein the two or more silicon-containing films include a silicon oxide film and a silicon nitride film. (B89) The etching method according to (B87), wherein the two or more silicon-containing films include a plurality of silicon oxide films and a plurality of silicon nitride films that are alternately stacked. (B90) The etching method according to (B87), wherein the two or more silicon-containing films include a silicon oxide film and a silicon film. (B91) The etching method according to (B87), wherein the two or more silicon-containing films include a plurality of silicon oxide films and a plurality of polysilicon films that are alternately stacked. (B92) The etching method according to any one of (B1) to (B91), wherein the substrate further includes a mask provided on the silicon-containing film.

[0149] (C1). (a) providing a substrate having a silicon-containing film and a mask in a chamber of a plasma processing apparatus; (b) generating a plasma from a process gas in the chamber to etch the silicon-containing film, the process gas including hydrogen fluoride gas, a phosphorus-containing gas, and a carbon-containing gas; An etching method comprising: (C2) The etching method according to (C1), wherein the flow rate of the hydrogen fluoride gas is the largest among the flow rates of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas. (C3) The processing gas further includes a rare gas; The etching method according to (C1), wherein the flow rate of the hydrogen fluoride gas is the largest among the flow rates of all gases in the processing gas except for the rare gas. (C4) The etching method according to any one of (C1) to (C3), wherein in (b), the temperature of a substrate support that supports the substrate is set to a temperature of 0° C. or lower. (C5) The etching method according to (C4), wherein in (b), the temperature of a substrate support that supports the substrate is set to a temperature of −40° C. or lower. (C6) The etching method according to any one of (C1) to (C5), wherein the phosphorus-containing gas contains a halogen element. (C7) The etching method according to (C6), wherein the halogen element is a halogen element other than fluorine. (C8) The etching method according to any one of (C1) to (C7), wherein the proportion of the flow rate of the phosphorus-containing gas in the total flow rate of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas is 2% or more. (C9) The etching method according to any one of (C1) to (C8), wherein the processing gas further contains a halogen-containing gas that does not contain fluorine. (C10) The etching method according to (C9), wherein the proportion of the flow rate of the halogen-containing gas in the total flow rate of the hydrogen fluoride gas, the phosphorus-containing gas, the carbon-containing gas, and the halogen-containing gas is greater than 0% and not more than 10%. (C11) The etching method according to any one of (C1) to (C10), wherein the silicon-containing film includes a silicon oxide film. (C12) The etching method according to (C11), wherein the silicon-containing film further includes a silicon nitride film. (C13) A process gas for plasma etching of silicon oxide films, comprising hydrogen fluoride gas, a phosphorus-containing gas, and a carbon-containing gas. (C14) The process gas according to (C13), wherein the flow rate of the hydrogen fluoride gas is the largest among the flow rates of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas. (C15) The processing gas further contains a rare gas; The process gas according to (C13), wherein the flow rate of the hydrogen fluoride gas is the largest among the flow rates of all gases in the process gas except for the rare gas. (C16) The process gas according to any one of (C13) to (C15), wherein the phosphorus-containing gas contains a halogen element. (C17) The process gas according to (C16), wherein the halogen element is a halogen element other than fluorine. (C18) The process gas according to any one of (C13) to (C15), wherein a proportion of the flow rate of the phosphorus-containing gas in the total flow rate of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas is 2% or more. (C19). A chamber; a substrate support disposed within the chamber; a gas supply configured to supply a process gas into the chamber, the process gas including a hydrogen fluoride gas, a phosphorus-containing gas, and a carbon-containing gas; a plasma generating unit configured to generate plasma from the processing gas; a controller configured to control the gas supply unit to supply the process gas into the chamber and to control the plasma generation unit to generate plasma from the process gas in the chamber to etch a silicon-containing film on a substrate supported by the substrate support; A plasma processing apparatus comprising:

[0150] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims. [Explanation of symbols]

[0151] 1...plasma processing apparatus, 10...chamber, 14...substrate support, 80...controller, W...substrate, SF...silicon-containing film.

Claims

1. (a) providing a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film; (b) setting the temperature of a substrate support that supports the substrate to 0° C. or less; (c) etching the silicon-containing film with chemical species from a plasma formed in the chamber from a process gas, the process gas including a phosphorus-containing gas, a fluorine-containing gas, and hydrogen fluoride, H ２ the process including a hydrogen-containing gas containing at least one selected from the group consisting of ammonia, and hydrocarbons; An etching method comprising:

2. 2. The etching method according to claim 1, wherein the processing gas further contains a halogen-containing gas containing a halogen element other than fluorine.

3. (a) providing a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film; (b) setting the temperature of a substrate support that supports the substrate to 0° C. or less; (c) etching the silicon-containing film with chemical species from a plasma formed in the chamber from a process gas, the process gas including a phosphorus-containing gas, a fluorine-containing gas, a hydrofluorocarbon gas, and a halogen-containing gas containing a halogen element other than fluorine; An etching method comprising:

4. The halogen-containing gas is Cl ２ 4. The etching method according to claim 2, wherein the gas is HBr gas and / or HBr gas.

5. 5. The etching method according to claim 1, wherein the fluorine-containing gas includes at least one gas selected from the group consisting of a fluorocarbon gas and a carbon-free fluorine-containing gas.

6. 6. The etching method according to claim 5, wherein the carbon-free fluorine-containing gas is nitrogen trifluoride gas or sulfur hexafluoride gas.

7. a flow rate ratio of the second gas to the first gas in the processing gas is greater than 0 and not greater than 0.5; the first gas is all gases contained in the process gas other than the phosphorus-containing gas, the second gas is the phosphorus-containing gas; The etching method according to any one of claims 1 to 6.

8. 8. The etching method according to claim 7, wherein the flow rate ratio is equal to or greater than 0.075 and equal to or less than 0.

3.

9. 9. The etching method according to claim 1, further comprising the step of forming a protective film containing a combination of phosphorus and oxygen contained in the processing gas on a sidewall surface that defines the opening formed by the etching.

10. (c) includes periodically applying a pulse wave of an electric bias to a lower electrode of a substrate support that supports the substrate when the plasma is present in the chamber; The electrical bias is a high frequency bias power or a negative polarity DC voltage pulse wave. The etching method according to any one of claims 1 to 9.

11. 11. The etching method according to claim 10, wherein a frequency that defines a period during which the pulse wave of the electric bias is applied to the lower electrode is not less than 5 Hz and not more than 100 kHz.

12. 12. The etching method according to claim 1, wherein the silicon-containing film includes a silicon oxide film, a silicon oxide film and a silicon nitride film, or a silicon oxide film and a polycrystalline silicon film.

13. a chamber; a substrate support disposed within the chamber; Phosphorus-containing gas, fluorine-containing gas, and hydrogen fluoride, H ２ a gas supply configured to supply a process gas into the chamber, the process gas including a hydrogen-containing gas containing at least one selected from the group consisting of ammonia, and a hydrocarbon; a plasma generating unit configured to generate plasma from the processing gas; a chiller unit configured to supply a heat exchange medium to a flow channel in a lower electrode of the substrate support; A control unit; Equipped with The control unit configured to control the gas supply unit to supply the process gas into the chamber and to control the plasma generation unit to generate plasma from the process gas in the chamber to etch a silicon-containing film on a substrate supported by the substrate support; and controlling the chiller unit to supply the heat exchange medium to the flow path to set the temperature of the substrate support to 0° C. or less before generating the plasma. Plasma processing equipment.

14. a chamber; a substrate support disposed within the chamber; a gas supply unit configured to supply a process gas into the chamber, the process gas including a phosphorus-containing gas, a fluorine-containing gas, a hydrofluorocarbon gas, and a halogen-containing gas containing a halogen element other than fluorine; a plasma generating unit configured to generate plasma from the processing gas; a chiller unit configured to supply a heat exchange medium to a flow channel in a lower electrode of the substrate support; A control unit; Equipped with The control unit configured to control the gas supply unit to supply the process gas into the chamber and to control the plasma generation unit to generate plasma from the process gas in the chamber to etch a silicon-containing film on a substrate supported by the substrate support; and controlling the chiller unit to supply the heat exchange medium to the flow path to set the temperature of the substrate support to 0° C. or less before generating the plasma. Plasma processing equipment.

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