Etching method

Abstract

The etching method disclosed herein includes a process (a) of preparing a substrate within a chamber of a plasma processing apparatus. The substrate includes a silicon-containing film. The etching method also includes a process (b) of etching the silicon-containing film by chemical species from a plasma formed from a process gas within the chamber. The process gas includes a phosphorous-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.

Description

[0001] This application is a divisional application of Chinese application number 202080005420.2, filed on November 2, 2020, entitled "Etching Method". Technical Field

[0002] Exemplary embodiments of the present invention relate to an etching method, a processing gas, and a plasma processing apparatus. Background Technology

[0003] In the manufacture of electronic devices, plasma etching is performed on silicon-containing films of substrates. During plasma etching, plasma generated from a process gas is used to etch the silicon-containing film. U.S. Patent Application Publication No. 2016 / 0343580 discloses a process gas containing fluorocarbon gas as a process gas for plasma etching of silicon-containing films. Japanese Patent Application Publication No. 2016-39310 discloses a process gas containing hydrocarbon gas and hydrofluorocarbon gas as a process gas for plasma etching of silicon-containing films.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: U.S. Patent Application Publication No. 2016 / 0343580

[0007] Patent Document 2: Japanese Patent Application Publication No. 2016-39310 Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] This invention provides a technique for increasing the etching rate when performing plasma etching on silicon-containing films.

[0010] means for solving technical problems

[0011] In one exemplary embodiment, an etching method is provided. The etching method includes a step (a) of preparing a substrate within 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 by means of chemical species from a plasma formed from a process gas within the chamber. The process 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.

[0012] Invention Effects

[0013] According to an exemplary embodiment, it becomes possible to increase the etching rate when performing plasma etching on silicon-containing films. Attached Figure Description

[0014] Figure 1 This is a flowchart of an exemplary embodiment of an etching method.

[0015] Figure 2 It is applicable Figure 1 A partially enlarged cross-sectional view of a substrate for an example of the etching method shown.

[0016] Figure 3 This is a diagram schematically illustrating a plasma processing apparatus according to an exemplary embodiment.

[0017] Figure 4 middle, Figure 4 (a) is applicable Figure 1 A partially enlarged cross-sectional view of a substrate illustrating an example of the etching method. Figure 4 (b) is a partially enlarged cross-sectional view of an example substrate etched by a plasma formed from a phosphorus-free processing gas.

[0018] Figure 5 This is an example timing diagram of an etching method according to an exemplary embodiment.

[0019] Figure 6 middle, Figure 6 (a) is a graph showing the XPS analysis results of the protective film PF formed in an experimental example of etching a silicon oxide film in the STP process. Figure 6 (b) is a graph showing the results of XPS analysis of the protective film PF formed in an experimental example where the silicon nitride film was etched in the STP process.

[0020] Figure 7 This is another timing diagram of an etching method according to an exemplary embodiment.

[0021] Figure 8 This is a graph showing the relationship between the flow rate of PF3 gas in the treatment gas and the etching rate of the silicon oxide film, as determined in Experiment 1.

[0022] Figure 9 This is a graph showing the relationship between the flow rate of PF3 gas in the treatment gas determined in Experiment 1 and the maximum width of the opening formed on the silicon oxide film.

[0023] Figure 10 This is a graph showing the relationship between the flow rate of PF3 gas and the selectivity in the treated gas, as determined in Experiment 1.

[0024] Figure 11 This is a graph showing the relationship between the flow rate of PF3 gas determined in Experiment 2 and the etching rate of the silicon-containing film, the etching rate of the mask, and the selectivity.

[0025] Figure 12 This is a flowchart of an etching method according to another exemplary embodiment.

[0026] Figure 13 It is applicable Figure 12 A partially enlarged cross-sectional view of a substrate for an example of the etching method shown.

[0027] Figure 14 It is applicable Figure 12 A partially enlarged cross-sectional view of a substrate for an example of the etching method shown.

[0028] Figure 15 This is an example timing diagram of an etching method according to another exemplary embodiment.

[0029] Figure 16 This is a graph representing the results of experiment 7.

[0030] Figure 17 This is a chart showing the results of experiments 8 through 11.

[0031] Figure 18 middle, Figure 18 (a) is a graph showing the results of experiment 12. Figure 18 (b) is a graph showing the results of experiment 13. Detailed Implementation

[0032] The following describes various exemplary embodiments.

[0033] In one exemplary embodiment, an etching method is provided. The etching method includes a step (a) of preparing a substrate within 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 by means of chemical species from a plasma formed from a process gas within the chamber. The process 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.

[0034] In one exemplary embodiment, the processing gas may also include a halogen-containing gas containing halogen elements other than fluorine.

[0035] In another exemplary embodiment, an etching method is provided. The etching method includes a step (a) of preparing a substrate within 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 by means of chemical species from a plasma formed from a process gas within the chamber. The process gas includes a phosphorus-containing gas, a fluorine-containing gas, a hydrofluorocarbon gas, and a halogen-containing gas. The halogen-containing gas contains halogen elements other than fluorine.

[0036] In one exemplary embodiment, the aforementioned fluorinated gas may comprise at least one gas selected from the group consisting of fluorocarbon gases and carbon-free fluorinated gases. The carbon-free fluorinated gas may be nitrogen trifluoride gas or sulfur hexafluoride gas.

[0037] In one exemplary embodiment, the halogen-containing gas may be Cl2 gas and / or HBr gas.

[0038] In one exemplary embodiment, the flow ratio of the second gas to the first gas in the aforementioned processing gas can be greater than 0 and less than 0.5. The first gas includes all gases contained in the processing gas except for phosphorus-containing gases. The second gas is a phosphorus-containing gas. The flow ratio can be greater than 0.075 and less than 0.3.

[0039] In one exemplary embodiment, the etching method may further include a step of forming a protective film containing the bonds of phosphorus and oxygen contained in the processing gas on the sidewall surface of the opening formed by etching.

[0040] In one exemplary embodiment, step (b) may include periodically applying an electrically biased pulse wave to the lower electrode of a substrate support for supporting a substrate when plasma is present in the chamber. The electrical bias is a pulse wave of high-frequency bias power or negative DC voltage. The frequency defining the period of the pulse wave applying the electrical bias to the lower electrode may be 5 Hz or more and 100 kHz or less.

[0041] In one exemplary embodiment, the etching method may further include a step of setting the temperature of the substrate support to below 0°C before step (b).

[0042] In another exemplary embodiment, an etching method is provided. The etching method includes a step of preparing a substrate within a cavity of a plasma processing apparatus. The substrate has a silicon-containing film and a mask. The etching method includes a step of etching the silicon-containing film by generating plasma from a process gas within the cavity. The process gas includes hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas.

[0043] In one exemplary embodiment, the flow rate of hydrogen fluoride gas can be the largest among the flow rates of hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas.

[0044] In one exemplary embodiment, the process gas may also include a rare gas. Among the respective flow rates of all gases in the process gas other than the rare gas, the flow rate of hydrogen fluoride gas may be the highest.

[0045] In one exemplary embodiment, in step (b), the temperature of the substrate support for the substrate can be set to a temperature below 0°C or a temperature below -40°C.

[0046] In one exemplary embodiment, the phosphorus-containing gas may contain halogen elements. The halogen elements in the phosphorus-containing gas may be halogen elements other than fluorine.

[0047] In one exemplary embodiment, the proportion of phosphorus-containing gas flow rate in the total flow rate of hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas can be 2% or more.

[0048] In one exemplary embodiment, the process gas may further comprise a halogen-containing gas that is fluorine-free. The proportion of the halogen-containing gas flow rate in the total flow rates of hydrogen fluoride gas, phosphorus-containing gas, carbon-containing gas, and halogen-containing gas may be greater than 0% and less than 10%.

[0049] In one exemplary embodiment, the silicon-containing film may include a silicon oxide film. The silicon-containing film may also include a silicon nitride film.

[0050] In another exemplary embodiment, a processing gas for plasma etching of a silicon oxide film is provided. The processing gas includes hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas.

[0051] In one exemplary embodiment, the flow rate of hydrogen fluoride gas can be the largest among the flow rates of hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas.

[0052] In one exemplary embodiment, the processing gas may also include a rare gas, and of all the gases in the processing gas other than the rare gas, the flow rate of hydrogen fluoride gas may be the largest.

[0053] In one exemplary embodiment, the phosphorus-containing gas may contain halogen elements. The halogen elements may be any halogen element other than fluorine.

[0054] In one exemplary embodiment, the proportion of the phosphorus-containing gas flow rate in the total flow rate of hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas can be 2% or more.

[0055] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. Furthermore, in the drawings, the same or equivalent parts are labeled with the same symbols.

[0056] Figure 1 This is a flowchart of an exemplary embodiment of an etching method. Figure 1 The etching method shown (hereinafter referred to as "Method MT") is applicable to substrates having a silicon-containing film. In Method MT, the silicon-containing film is etched.

[0057] Figure 2 It is applicable Figure 1 A partially enlarged cross-sectional view of a substrate for an example of the etching method shown. Figure 2 The substrate W shown 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 also have a substrate region UR. The silicon-containing film SF can be disposed on the substrate region UR.

[0058] The silicon-containing film SF can be a silicon-containing dielectric film. The silicon-containing dielectric film can include a silicon oxide film or a silicon nitride film. The silicon-containing dielectric film can also be a film of other film types, as long as it contains silicon. Furthermore, the silicon-containing film SF can include a silicon film (e.g., a polycrystalline silicon film). Furthermore, the silicon-containing film SF can include at least one of a silicon nitride film, a polycrystalline silicon film, a silicon carbon film, and a low-dielectric-constant film. The silicon carbon film can include a SiC film and / or a SiOC film. The low-dielectric-constant film contains silicon and can be used as an interlayer insulating film. Furthermore, the silicon-containing film SF can include two or more silicon-containing films having different film types from each other. The two or more silicon-containing films can include a silicon oxide film and a silicon nitride film. The silicon-containing film SF can, for example, be a multilayer film comprising one or more silicon oxide films and one or more silicon nitride films alternately stacked. The silicon-containing film SF can be a multilayer film comprising multiple silicon oxide films and multiple silicon nitride films alternately stacked. Alternatively, the two or more silicon-containing films can include a silicon oxide film and a silicon film. The silicon-containing SF can be, for example, a multilayer film comprising one or more alternating layers of silicon oxide films and one or more silicon films. Alternatively, the two or more silicon-containing films may include silicon oxide films, silicon nitride films, and silicon films.

[0059] The substrate W may also have a mask MK. The mask MK is disposed on a 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 process 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, for example, of an amorphous carbon film, a photoresist film, or a spin-coated carbon film (SOC film). Alternatively, the mask MK may be formed of a silicon-containing film such as a silicon-containing antireflective 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.

[0060] The mask MK is patterned. That is, the mask MK has a pattern that is transferred onto the silicon-containing film SF in step ST2. If the pattern of the mask MK is transferred onto the silicon-containing film SF, openings (recesses) such as holes or trenches are formed on the silicon-containing film SF. In step ST2, the aspect ratio of the openings formed on the silicon-containing film SF can be 20 or more, or 30 or more, 40 or more, or 50 or more. In addition, the mask MK can have line and spatial patterns.

[0061] In the MT method, a plasma treatment device is used for etching the silicon-containing SF film. Figure 3 This is a diagram schematically illustrating a plasma processing apparatus according to an exemplary embodiment. Figure 3 The plasma processing apparatus 1 shown includes a chamber 10. The chamber 10 provides an internal space 10s within itself. The chamber 10 includes a chamber body 12. The chamber body 12 has a generally cylindrical shape. The chamber body 12 is formed, for example, of aluminum. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The corrosion-resistant film can be formed of ceramics such as alumina or yttrium oxide.

[0062] A channel 12p is formed on the side wall of the chamber body 12. The substrate W is transported between the internal space 10s and the outside of the chamber 10 through the channel 12p. The channel 12p is opened and closed by a gate valve 12g. The gate valve 12g is provided along the side wall of the chamber body 12.

[0063] A support portion 13 is provided at the bottom of the chamber body 12. The support portion 13 is formed of an insulating material. The support portion 13 has a generally cylindrical shape. The support portion 13 extends upward from the bottom of the chamber body 12 within the internal space 10s. The support portion 13 supports a substrate support 14. The substrate support 14 is configured to support the substrate W within the internal space 10s.

[0064] The substrate support 14 has a lower electrode 18 and an electrostatic chuck 20. The substrate support 14 may also have an electrode plate 16. The electrode plate 16 is formed of a conductor such as aluminum and has a generally disc-shaped form. The lower electrode 18 is disposed on the electrode plate 16. The lower electrode 18 is formed of a conductor such as aluminum and has a generally disc-shaped form. The lower electrode 18 is electrically connected to the electrode plate 16.

[0065] An electrostatic chuck 20 is disposed on the lower electrode 18. A substrate W is placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a main body and electrodes. The main body of the electrostatic chuck 20 has a generally disc-shaped shape and is formed of a dielectric. The electrodes of the electrostatic chuck 20 are film electrodes and are disposed within the main body of the electrostatic chuck 20. The electrodes of the electrostatic chuck 20 are connected to a DC power supply 20p via a switch 20s. When a voltage from the DC power supply 20p is applied to the electrodes of the electrostatic chuck 20, an electrostatic attraction is generated between the electrostatic chuck 20 and the substrate W. The substrate W is attracted to the electrostatic chuck 20 by this electrostatic attraction and is held by the electrostatic chuck 20.

[0066] An edge ring 25 is disposed on the substrate support 14. The edge ring 25 is a ring-shaped component. The edge ring 25 can be formed of silicon, silicon carbide, or quartz, etc. The substrate W is disposed on the electrostatic chuck 20 and within the area surrounded by the edge ring 25.

[0067] A flow path 18f is provided inside the lower electrode 18. A heat exchange medium (e.g., refrigerant) is supplied to the flow path 18f from a cooler unit located outside the chamber 10 via a pipe 22a. The heat exchange medium supplied to the flow path 18f returns to the cooler 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.

[0068] A gas supply line 24 is provided in the plasma processing apparatus 1. The gas supply line 24 supplies heat transfer gas (e.g., He gas) from the 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.

[0069] The plasma processing apparatus 1 also includes an upper electrode 30. The upper electrode 30 is disposed above the substrate support 14. The upper electrode 30 is supported on the upper part of the chamber body 12 via a component 32. The component 32 is formed of an insulating material. The upper electrode 30 and the component 32 close the upper opening of the chamber body 12.

[0070] The upper electrode 30 may include a top plate 34 and a support 36. The lower surface of the top plate 34 is the lower surface of one side of the internal space 10s, and divides the internal space 10s. The top plate 34 may be formed of a low-resistance conductor or semiconductor that generates little Joule heat. The top plate 34 has a plurality of gas vent holes 34a extending through the top plate 34 along its thickness direction.

[0071] The support body 36 can be detachably mounted and dismounted to support the top plate 34. The support body 36 is made of a conductive material such as aluminum. A gas diffusion chamber 36a is provided inside the support body 36. The support body 36 has a plurality of gas holes 36b extending downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are respectively connected to a plurality of gas exhaust holes 34a. A gas inlet 36c is formed in the support body 36. The gas inlet 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet 36c.

[0072] A gas source group 40 is connected to the gas supply pipe 38 via a flow controller group 41 and a valve group 42. The flow controller group 41 and the valve group 42 constitute the gas supply unit. The gas supply unit may also include the gas source group 40. The gas source group 40 includes multiple gas sources. The multiple gas sources include the source of the process gas used in method MT. The flow controller group 41 includes multiple flow controllers. The multiple flow controllers of the flow controller group 41 are either mass flow controllers or pressure control flow controllers. The valve group 42 includes multiple on / off valves. The multiple gas sources of the gas source group 40 are respectively connected to the gas supply pipe 38 via the flow controllers corresponding to the flow controller group 41 and the on / off valves corresponding to the valve group 42.

[0073] In the plasma processing apparatus 1, a shielding element 46 is detachably provided along the inner wall of the chamber body 12 and the outer periphery of the support portion 13. The shielding element 46 prevents reaction byproducts from adhering to the chamber body 12. The shielding element 46 is constructed, for example, by forming a corrosion-resistant film on the surface of a base material formed of aluminum. The corrosion-resistant film can be formed of ceramics such as yttrium oxide.

[0074] A baffle 48 is provided between the support portion 13 and the side wall of the chamber body 12. The baffle 48 is constructed, for example, by forming a corrosion-resistant film (such as yttrium oxide) on the surface of a component made of aluminum. Multiple through holes are formed in the baffle 48. An exhaust port 12e is provided below the baffle 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 includes a pressure regulating valve and a vacuum pump such as a turbomolecular pump.

[0075] 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 source for generating 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 in the range of 27MHz to 100MHz. The high-frequency power supply 62 is connected to the lower electrode 18 via a matching device 66 and an electrode plate 16. The matching device 66 has circuitry for matching the impedance of the load side (lower electrode 18 side) of the high-frequency power supply 62 with the output impedance of the high-frequency power supply 62. In addition, the high-frequency power supply 62 can be connected to the upper electrode 30 via the matching device 66. The high-frequency power supply 62 constitutes an example of a plasma generation unit.

[0076] The bias power supply 64 is a power source for generating an electrical bias. The bias power supply 64 is electrically connected to the lower electrode 18. The electrical bias has a second frequency. The second frequency is lower than the first frequency. The second frequency is, for example, a frequency in the range of 400 kHz to 13.56 MHz. When used with high-frequency power (HF), the electrical bias is applied to the substrate support 14 (in one example, the lower electrode 18) to introduce ions into the substrate W. When the electrical bias is applied to the lower electrode 18, the potential of the substrate W placed on the substrate support 14 varies within a period defined by the second frequency.

[0077] In one embodiment, the electrical bias can be a high-frequency power LF having a second frequency. When used in conjunction with high-frequency power HF, the high-frequency power LF serves as a high-frequency bias power for introducing ions into 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 matching adapter 68 and an electrode plate 16. The matching adapter 68 has circuitry for matching the impedance on the load side (lower electrode 18 side) of the bias power supply 64 with the output impedance of the bias power supply 64.

[0078] Furthermore, high-frequency power LF is used instead of high-frequency power HF, meaning that plasma can be generated using only a single high-frequency power source. In this case, the frequency of the high-frequency power LF can be greater than 13.56 MHz, for example, 40 MHz. Also, in this case, the plasma processing apparatus 1 may not include the high-frequency power supply 62 and the matching device 66. In this case, the bias power supply 64 constitutes an example of a plasma generation unit.

[0079] In another embodiment, the electrical bias can be a pulse wave of DC voltage. The DC voltage pulse wave is periodically generated and applied to the lower electrode 18. The period of the DC voltage pulse wave is defined by a second frequency. The period of the DC voltage pulse wave includes two periods. The DC voltage during one of the two periods is a negative DC voltage. The level (i.e., absolute value) of the DC voltage during one of the two periods is higher than the level (i.e., absolute value) of the DC voltage during the other period. The DC voltage during the other period can be either negative or positive. The level of the negative DC voltage during the other period can be greater than zero or zero. In this embodiment, the bias power supply 64 is connected to the lower electrode 18 via a low-pass filter and electrode plate 16. Additionally, the pulse wave used for electrical bias can contain a pulsed voltage with a waveform other than DC.

[0080] In one embodiment, the bias power supply 64 can provide a continuous electrical bias wave to the lower electrode 18. That is, the bias power supply 64 can continuously provide electrical bias to the lower electrode 18. During the execution of step STP or steps ST2 and ST3 of method MT, the continuous electrical bias wave is applied to the lower electrode 18.

[0081] In another embodiment, the bias power supply 64 can provide an electrically biased pulse wave to the lower electrode 18. The electrically biased pulse wave can be applied to the lower electrode 18 periodically. The period of the electrically biased pulse wave 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 other examples, the third frequency can be 5 Hz or more and 100 kHz or less.

[0082] The period of the bias pulse wave includes two periods: the H period and the L period. The bias level during the H period (i.e., the level of the bias pulse) is higher than the bias level during the L period. That is, the bias pulse wave can be applied to the lower electrode 18 by increasing or decreasing the bias level. The bias level during the L period can be greater than zero. Alternatively, the bias level during the L period can be zero. That is, the bias pulse wave can be applied to the lower electrode 18 by alternately switching the supply and stop supply of the bias to the lower electrode 18. Wherein, when the bias is a high-frequency power LF, the bias level is the power level of the high-frequency power LF. When the bias is a high-frequency power LF, the high-frequency power LF level in the bias pulse can be 2kW or higher. When the bias is a negative DC voltage pulse wave, the bias level is the effective value of the absolute value of the negative DC voltage. The duty cycle of the electrically biased pulse wave, that is, the proportion of period H in the period of the electrically biased pulse wave, is, for example, 1% or more and 80% or less. In another example, the duty cycle of the electrically biased pulse wave can be 5% or more and 50% or less. Alternatively, the duty cycle of the electrically biased pulse wave can be 50% or more and 99% or less. To perform steps ST2 and ST3 of method MT, the electrically biased pulse wave can be applied to the lower electrode 18.

[0083] In one embodiment, the high-frequency power supply 62 can supply a continuous wave of high-frequency power HF. That is, the high-frequency power supply 62 can continuously supply high-frequency power HF. During the execution of step STP or steps ST2 and ST3 of method MT, a continuous wave of high-frequency power HF can be supplied.

[0084] In another embodiment, the high-frequency power supply 62 can supply a pulse wave of high-frequency power HF. The pulse wave of high-frequency power HF can 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, the H period and the L period. The power level of high-frequency power HF during the H period is higher than the power level of high-frequency power HF during the L period. The power level of high-frequency power HF during the L period can be greater than zero or zero.

[0085] Furthermore, the period of the high-frequency (HF) power pulse wave can be synchronized with the period of the electrically biased pulse wave. The H-period within the period of the HF power pulse wave can be synchronized with the H-period within the period of the electrically biased pulse wave. Alternatively, the H-period within the period of the HF power pulse wave may not be synchronized with the H-period within the period of the electrically biased pulse wave. The duration of the H-period within the period of the HF power pulse wave can be the same as or different from the duration of the H-period within the period of the electrically biased pulse wave.

[0086] In the plasma processing apparatus 1, gas is supplied from the gas supply unit to the internal space 10s. Furthermore, 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 electrical bias. The generated high-frequency electric field generates plasma from the gas in the internal space 10s.

[0087] The plasma processing apparatus 1 may also include a control unit 80. The control unit 80 may be a computer equipped with a processor, memory, and other storage units, input devices, a display device, and signal input / output interfaces. The control unit 80 controls each part of the plasma processing apparatus 1. In the control unit 80, the operator can use the input devices to input commands and manage the plasma processing apparatus 1. Furthermore, the control unit 80 can visualize and display the operating status of the plasma processing apparatus 1 via the display device. Moreover, the storage unit stores control programs and recipe data. The control program is executed by the processor to perform various processes within the plasma processing apparatus 1. The processor executes the control program and controls each part of the plasma processing apparatus 1 according to the recipe data.

[0088] Refer again Figure 1 The following describes method MT, using plasma processing apparatus 1 suitable for method MT. Figure 2 The case of substrate W shown will be used as an example for explanation. When using plasma processing apparatus 1, method MT can be executed in plasma processing apparatus 1 by controlling each part of plasma processing apparatus 1 by control unit 80. In the following explanation, the control of each part of plasma processing apparatus 1 by control unit 80 for executing method MT will also be explained.

[0089] In the following description, except Figure 1 In addition, refer to Figure 4 (a) Figure 4 (b) and Figure 5 . Figure 4 (a) is applicable Figure 1 A partially enlarged cross-sectional view of a substrate illustrating an example of the etching method. Figure 4 (b) is a partially enlarged cross-sectional view of an example substrate etched by a plasma formed from a phosphorus-free processing gas. Figure 5 This is an example timing diagram of an etching method according to an exemplary embodiment. Figure 5 In the diagram, the horizontal axis represents time. Figure 5In the diagram, the vertical axis represents the power level of the high-frequency power (HF), the electrical bias level, and the supply status of the processing gas. An "L" level for the HF indicates that no HF is being supplied or that the HF power level is lower than the level represented by "H". An "L" level for the electrical bias indicates that the electrical bias is not being applied to the lower electrode 18 or that the electrical bias level is lower than the level represented by "H". Furthermore, an "ON" state for the processing gas supply status indicates that processing gas is being supplied to the chamber 10, and an "OFF" state indicates that the supply of processing gas to the chamber 10 is stopped.

[0090] like Figure 1 As shown, method MT begins in step ST1. In step ST1, substrate W is prepared within chamber 10. Substrate W is placed on electrostatic chuck 20 within chamber 10 and held by electrostatic chuck 20. Additionally, substrate W may have a diameter of 300 mm.

[0091] In method MT, step STP is then performed. In step STP, plasma treatment is performed on substrate W. In step STP, plasma is generated from the process gas within chamber 10. Method MT includes step ST2. Step ST2 is performed during the execution of step STP. Method MT may also include step ST3. Step ST3 is performed during the execution of step STP. Steps ST2 and ST3 may occur simultaneously or independently of each other.

[0092] In step ST2, the silicon-containing film SF is etched in step STP using chemical species from the plasma generated from the process gas within chamber 10. In step ST3, the protective film PF is formed on the substrate W in step STP using chemical species from the plasma generated from the process gas within chamber 10. The protective film PF is formed on the sidewall surface that divides the opening formed on the silicon-containing film SF.

[0093] The processing gas used in the STP process contains halogen elements and phosphorus. The halogen element in the processing gas can be fluorine. The processing gas may contain at least one halogen-containing molecule. The processing gas may contain at least one of fluorocarbons or hydrofluorocarbons as at least one halogen-containing molecule. Fluorocarbons are, for example, at least one of CF4, C3F8, C4F6, or C4F8. Hydrofluorocarbons are, for example, at least one of CH2F2, CHF3, or CH3F. Hydrofluorocarbons may contain two or more carbons. Hydrofluorocarbons may, for example, contain three or four carbons.

[0094] The treated gas may contain at least one phosphorus-containing molecule. The phosphorus-containing molecule may be, for example, phosphorus tetraoxide (P₄O₃). 10Phosphorus oxides include tetraphosphorus octoxide (P4O8) and tetraphosphorus hexaoxide (P4O6). Tetraphosphorus decaoxide is sometimes called diphosphorus pentoxide (P2O5). Phosphorus-containing molecules can be halides such as phosphorus trifluoride (PF3), phosphorus pentafluoride (PF5), phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), phosphorus tribromide (PBr3), phosphorus pentabromide (PBr5), and phosphorus iodide (PI3). That is, phosphorus-containing molecules can contain fluorine as a halogen element. Alternatively, phosphorus-containing molecules can contain halogen elements other than fluorine as halogen elements. Phosphorus-containing molecules can be phosphoric halides such as phosphoric acid fluoride (POF3), phosphoric acid chloride (POCl3), and phosphoric acid bromide (POBr3). Phosphorus-containing molecules can be phosphine (PH3), calcium phosphide (Ca3P2, etc.), phosphoric acid (H3PO4), sodium phosphate (Na3PO4), hexafluorophosphate (HPF6), etc. Phosphorus-containing molecules can be fluorophosphine derivatives (H... x PF y In this case, the sum of x and y is 3 or 5. Examples of fluorophosphine molecules include HPF2 and H2PF3. The processing gas may contain one or more of the above-mentioned phosphorus-containing molecules as at least one phosphorus-containing molecule. For example, the processing gas may contain at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3, or PBr5 as at least one phosphorus-containing molecule. Furthermore, if the phosphorus-containing molecules contained in the processing gas are liquid or solid, they can be vaporized by heating or the like and supplied to the chamber 10.

[0095] The processing gases used in the STP process can also contain carbon and hydrogen. Processing gases can contain H2, hydrogen fluoride (HF), and hydrocarbons (C). x H y ), hydrofluorocarbons (CH) x F y The process gas may contain at least one of the following: NH3 or NH4, as a molecule containing hydrogen. Hydrocarbons may be, for example, CH4 or C3H6. Wherein, x and y are natural numbers. The process gas may contain fluorocarbons or hydrocarbons (e.g., CH4) as molecules containing carbon. The process gas may also contain oxygen. For example, the process gas may contain O2. Alternatively, the process gas may not contain oxygen.

[0096] In one embodiment, the processing gas comprises 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 (HF), H2, ammonia (NH3), and hydrocarbons. The phosphorus-containing gas contains at least one of the aforementioned phosphorus-containing molecules. The fluorine-containing gas comprises at least one gas selected from the group consisting of fluorocarbon gases and carbon-free fluorine-containing gases. The fluorocarbon gas is a gas containing the aforementioned fluorocarbons. The carbon-free fluorine-containing gas is, for example, nitrogen trifluoride gas (NF3 gas) or sulfur hexafluoride gas (SF6 gas). Furthermore, the processing gas may also contain a hydrofluorocarbon gas. The hydrofluorocarbon gas is a gas containing the aforementioned hydrofluorocarbons. Furthermore, the processing gas may also contain a halogen-containing gas containing a halogen element other than fluorine. The halogen-containing gas is, for example, Cl2 gas and / or HBr gas.

[0097] One example of a process gas includes or is substantially composed of phosphorus-containing gases, fluorocarbon gases, hydrogen-containing gases, and oxygen-containing gases (e.g., O2 gas). Another example of a process gas includes or is substantially composed of phosphorus-containing gases, carbon-free fluorine-containing gases, fluorocarbon gases, hydrogen-containing gases, hydrofluorocarbon gases, and halogen-containing gases containing halogen elements other than fluorine.

[0098] In another embodiment, the processing gas comprises the aforementioned phosphorus-containing gas, the aforementioned fluorine-containing gas, the aforementioned hydrofluorocarbon gas, and the aforementioned halogen-containing gas containing halogen elements other than fluorine, or substantially consists of these.

[0099] In one embodiment, the processing gas may comprise a first gas and a second gas. The first gas is a phosphorus-free gas. That is, the first gas comprises all gases included in the processing gas except for phosphorus-containing gases. The first gas may contain halogen elements. The first gas may contain at least one of the aforementioned halogen-containing molecules. The first gas may also contain carbon and hydrogen. The first gas may also contain the aforementioned gases containing hydrogen molecules and / or gases containing carbon molecules. The first gas may also contain oxygen. The first gas may contain O2 gas. Alternatively, the first gas may not contain oxygen. The second gas is a phosphorus-containing gas. That is, the second gas is the aforementioned phosphorus-containing gas. The second gas may contain at least one of the aforementioned phosphorus-containing molecules.

[0100] In the process STP, the flow ratio of the second gas to the first gas can be set to be greater than 0 and less than 0.5. The flow ratio can be set to be greater than 0.075 and less than 0.3. The flow ratio can be set to be greater than 0.1 and less than 0.25.

[0101] like Figure 5As shown, in the STP process, a process gas is supplied into chamber 10. In the STP process, the pressure of the gas within chamber 10 is set to a specified pressure. In the STP process, the pressure of the gas within chamber 10 can be set to a pressure of 5 mTorr (0.65 Pa) or higher and 100 mTorr (13.3 Pa) or lower. Furthermore, in the STP process, high-frequency power (HF) is supplied to generate plasma from the process gas within chamber 10. Figure 5 As shown by the solid line, a continuous wave of high-frequency power (HF) can be supplied in the STP process. High-frequency power (LF) can be used instead of high-frequency power (HF) in the STP process. Both high-frequency power (HF) and electrical bias can be supplied in the STP process. For example... Figure 5 As shown by the solid line, in process STP, a continuous electrical bias wave can be applied to the lower electrode 18. The power level of the high-frequency power HF can be set to a level of 2kW or higher and 10kW or lower. When using high-frequency power LF as the electrical bias, the power level of the high-frequency power LF can be set to a level of 2kW or higher. The power level of the high-frequency power LF can be set to a level of 10kW or higher.

[0102] In order to perform process STP, the control unit 80 controls the gas supply unit to supply process gas into the chamber 10. Furthermore, the control unit 80 controls the exhaust device 50 to set the pressure of the gas in the chamber 10 to a specified pressure. Additionally, 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 electrical bias.

[0103] In order to perform process ST2, the control unit 80 controls the gas supply unit to supply processing gas into the chamber 10. Furthermore, the control unit 80 controls the exhaust device 50 to set the pressure of the gas in the chamber 10 to a specified pressure. Additionally, 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 electrical bias.

[0104] In one embodiment of the method MT, the temperature of the substrate W at the start of process ST2 (or process STP) can be set to 0°C or lower. If the temperature of the substrate W is set to this temperature, the etching rate of the silicon-containing film SF in process ST2 increases. To set the temperature of the substrate W at the start of process ST2, the control unit 80 can control the cooler unit. Alternatively, the temperature of the substrate W during the execution of process ST2 (or process STP) can be 200°C or lower. As long as the temperature of the substrate W during the execution of process ST2 (or process STP) is 200°C or lower, phosphorus chemical species used as etchants can be adequately supplied to the bottom of the openings formed on the silicon-containing film SF.

[0105] According to Arrhenius's rate law, which defines the reaction rate as increasing with temperature, the amount of lateral 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 mentioned above, due to its low volatility (chemically robustness), the effectiveness of the protective film preventing lateral sidewall etching increases at low temperatures. Furthermore, due to high aspect ratio etching, ion energies tend to be higher, thus the inventors recognized the benefit of a lower etching temperature to improve the effectiveness of the protective film. Therefore, in this invention, a protective film with lower volatility (achieved by controlling the temperature of the substrate W) is more preferred as it helps suppress sidewall etching (Boeing).

[0106] In one embodiment, method MT may further include step STT. Step STT is performed before step ST2 (or step STP). In step STT, the temperature of substrate W is set to a temperature below 0°C. The temperature of substrate W at the start of step ST2 is set in step STT. In step STT, in order to set the temperature of substrate W, control unit 80 may control the cooler unit.

[0107] In process ST2, the silicon-containing film SF is etched using halogen chemical species from the plasma generated from the process gas. In one embodiment, the portion of the mask MK exposed over the entire region of the silicon-containing film SF is etched (see reference). Figure 4 (a)).

[0108] When the processing gas contains phosphorus-containing molecules such as PF3, which contain both phosphorus and halogen elements, the halogen chemical species derived from these molecules contribute to the etching of the silicon-containing SF film. Therefore, in process ST2, phosphorus-containing molecules such as PF3, which contain both phosphorus and halogen elements, increase the etching rate of the silicon-containing SF film.

[0109] In process ST3, a protective film PF is formed on the sidewall surface that divides the opening formed on the silicon-containing film SF by etching in process ST2 (see reference). Figure 4 (a)). The protective film PF is formed in process STP by chemical species from the plasma generated from the process gas within chamber 10. Process ST3 can be performed simultaneously with process ST2. For example... Figure 4 As shown in (a), in one embodiment, the protective film PF can be formed such that its thickness decreases along the depth direction of the opening formed on the silicon-containing film SF.

[0110] The protective film PF comprises silicon and phosphorus contained in the process gas used in the STP process. In one embodiment, the protective film PF may also comprise carbon and / or hydrogen contained in the process gas. In one embodiment, the protective film PF may also comprise oxygen contained in the process gas or in the silicon-containing film SF. In one embodiment, the protective film PF may comprise phosphorus-oxygen bonds.

[0111] Figure 6 (a) is a graph showing the XPS analysis results of the protective film PF formed in an experimental example of etching a silicon oxide film in the STP process. Figure 6 (b) is a graph showing the results of XPS analysis of the protective film PF formed in an experimental example where the silicon nitride film was etched in the STP process. Figure 6 (a) and Figure 6 (b) Represents the P2p spectrum. The conditions for the STP process in the experimental example are shown below.

[0112] <Conditions for STP process>

[0113] The gas pressure inside chamber 10: 100 mTorr (13.33 Pa)

[0114] Processed gases: PF3 gas at 50 sccm and Ar gas at 150 sccm

[0115] High-frequency power HF (continuous wave): 40MHz, 4500W

[0116] High-frequency power LF (continuous wave): 400kHz, 7000W

[0117] The temperature of the substrate (the temperature of the substrate support before etching begins): -70℃

[0118] The execution time of process STP is 30 seconds.

[0119] Based on an experimental example where a silicon oxide film was etched in the STP process, the XPS analysis results of the protective film PF are as follows: Figure 6 As shown in (a), Si-O bonding peaks and PO bonding peaks were observed. Furthermore, based on an experimental example where the silicon nitride film was etched in the STP process, the XPS analysis results of the protective film PF were obtained, as shown... Figure 6 As shown in (b), Si-P bonding peaks and PN bonding peaks were observed.

[0120] In one embodiment, the plasma of the processing gas 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 chemical species generated from the phosphorus-containing gas (a gas containing the aforementioned phosphorus-containing molecules) are present on the surface of the substrate W, the adsorption of hydrogen fluoride, i.e., the etchant, onto the substrate W is promoted. That is, when phosphorus chemical 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.

[0121] Furthermore, if the treated gas does not contain phosphorus, then as Figure 4 As shown in (b), the silicon-containing film SF is also etched laterally. As a result, the width of the openings formed on the silicon-containing film SF becomes locally wider. For example, the width of the openings formed on the silicon-containing film SF becomes locally wider near the mask MK.

[0122] On the other hand, in method MT, a protective film PF is formed on the sidewall surface that divides the opening formed on 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 becomes possible to suppress lateral etching during plasma etching of the silicon-containing film SF.

[0123] In one embodiment, during the continued execution of process STP, i.e., during the period when plasma is generated from the process gas in process STP, one or more cycles, each including process ST2 and process ST3, can be executed sequentially. Two or more cycles can be executed sequentially in process STP.

[0124] In one implementation, such as Figure 5 As shown by the dashed lines, the electrically biased pulse wave described above can be applied from the bias power supply 64 to the lower electrode 18 in process STP. That is, when plasma generated from the process gas is present in chamber 10, the electrically biased pulse wave can be applied from the bias power supply 64 to the lower electrode 18. In this embodiment, the etching of the silicon-containing film SF in process ST2 is mainly generated during period H within the period of the electrically biased pulse wave. Furthermore, the formation of the protective film PF in process ST3 is mainly generated during period L within the period of the electrically biased pulse wave.

[0125] Furthermore, when the electrical bias is set to high-frequency power (LF), the power level of the high-frequency power (LF) can be set to 2kW or higher during the H period of the electrical bias pulse wave period. During the H period of the electrical bias pulse wave period, the power level of the high-frequency power (LF) can be set to 10kW or higher.

[0126] In one implementation, such as Figure 5As shown by the dashed line, a pulse wave of the aforementioned high-frequency power (HF) can be supplied in process STP. During the H period of the HF pulse wave's cycle, the power level of the HF can be set to a level of 1kW or more and 10kW or less. For example... Figure 5 As shown, the period of a high-frequency power (HF) pulse wave can be synchronized with the period of an electrically biased pulse wave. For example... Figure 5 As shown, the H-period in the period of the high-frequency power (HF) pulse wave can be synchronized with the H-period in the period of the electrically biased pulse wave. Alternatively, the H-period in the period of the HF pulse wave can be unsynchronized with the H-period in the period of the electrically biased pulse wave. The duration of the H-period in the period of the HF pulse wave can be the same as or different from the duration of the H-period in the period of the electrically biased pulse wave.

[0127] Figure 7 This is another timing diagram regarding an etching method according to an exemplary embodiment. Figure 7 In the diagram, the horizontal axis represents time. Figure 7 In the diagram, the vertical axis represents the power level of the high-frequency power HF, the electrical bias level, the supply status of the first gas, and the supply status of the second gas. An "L" level for the high-frequency power HF indicates that high-frequency power HF is not supplied or that the power level of the high-frequency power HF is lower than the power level represented by "H". An "L" level for the electrical bias indicates that the electrical bias is not applied to the lower electrode 18 or that the electrical bias level is lower than the level represented by "H". Furthermore, an "ON" state for the first gas supply status indicates that the first gas is supplied to the chamber 10, and an "OFF" state for the first gas supply status indicates that the supply of the first gas to the chamber 10 is stopped. Similarly, an "ON" state for the second gas supply status indicates that the second gas is supplied to the chamber 10, and an "OFF" state for the second gas supply status indicates that the supply of the second gas to the chamber 10 is stopped.

[0128] like Figure 7 As shown, in process STP, the first gas and the second gas can be supplied to the chamber 10 alternately. The etching of the silicon-containing film SF in process ST2 is mainly produced during the period when the first gas is supplied to the chamber 10. Furthermore, the formation of the protective film PF in process ST3 is mainly produced during the period when the second gas is supplied to the chamber 10.

[0129] like Figure 7 As shown by the solid line, a continuous wave of high-frequency power (HF) can be supplied in the STP process. Alternatively, with... Figure 5 Similarly, as shown in the high-frequency power (HF) pulse wave, a high-frequency power (HF) pulse wave can be supplied in the STP process. The high-frequency power (HF) pulse wave in... Figure 7The dashed lines represent the period. The H period within the period of the high-frequency power HF pulse wave is synchronized with or partially repeats the period during which the first gas is supplied to the chamber 10. Furthermore, the L period within the period of the high-frequency power HF pulse wave is synchronized with or partially repeats the period during which the second gas is supplied to the chamber 10.

[0130] And, as Figure 7 As shown by the solid line, in the STP process, a continuous wave of electrical bias can be applied to the lower electrode 18. Alternatively, with... Figure 5 Similarly, in the STP process, the electrically biased pulse wave shown can be applied to the lower electrode 18. The electrically biased pulse wave in... Figure 7 The period is represented by a dashed line. The H period within the period of the electrically biased pulse wave is synchronized with or partially repeats the period during which the first gas is supplied to the chamber 10. Furthermore, the L period within the period of the electrically biased pulse wave is synchronized with or partially repeats the period during which the second gas is supplied to the chamber 10.

[0131] The effect achieved by pulsed bias power during etching is not primarily in deposition nor primarily in etching, but rather in creating a branching effect between the etching and deposition stages. Furthermore, etching primarily occurs when bias power is supplied to the lower electrode. Conversely, deposition primarily occurs when no bias power is supplied to the lower electrode. Alternating etching and deposition stages are achieved by applying pulsed bias power. In the etching stage, etching occurs after a protective film is formed to protect the sidewalls of the recess (opening) from lateral erosion. Therefore, a controlled etching can be provided: the flaring of the sidewalls is suppressed through a continuous phase of protective film formation (deposition) and subsequent etching, while simultaneously increasing the depth of the recess (opening). Furthermore, a mechanism can be provided to control the balance between the etching and deposition stages by changing the pulse duty cycle ((bias on-time) / (bias on-time + bias off-time)). A longer bias off-time helps form a thicker protective film, thus providing further protection against lateral erosion. A longer bias on-time increases the etching rate, thereby controlling the time required to reach the specified etching depth.

[0132] The first experiment conducted to evaluate the method MT will be described below. In the first experiment, multiple sample substrates were prepared. Each sample substrate had a silicon oxide film and a mask disposed on the silicon oxide film. The mask was formed of an amorphous carbon film. In the first experiment, the process step STP of the method MT was applied to the multiple sample substrates. The processing gas used for each of the multiple sample substrates contained PF3 gas at different flow rates. Another condition of the process STP is shown below. The flow rates of the PF3 gas were 0 sccm, 15 sccm, 30 sccm, 50 sccm, and 100 sccm, respectively. That is, in the first experiment, the flow rates of the second gas and the first gas were 0, 0.075, 0.15, 0.25, and 0.5, respectively.

[0133] <Conditions for STP process>

[0134] The gas pressure inside chamber 10: 25 mTorr (3.3 Pa)

[0135] Gases processed: CH4 at 50 sccm, CF4 at 100 sccm, and O2 at 50 sccm

[0136] High-frequency power HF (continuous wave): 40MHz, 4500W

[0137] High-frequency power LF (continuous wave): 400kHz, 7000W

[0138] Sample substrate temperature (substrate support temperature before etching begins): -30℃

[0139] The execution time of process STP is 600 seconds.

[0140] In Experiment 1, for each of the multiple sample substrates, the maximum width of the opening formed on the silicon oxide film, the etching rate of the silicon oxide film, and the selectivity were determined. The selectivity was obtained by dividing the etching rate of the silicon oxide film by the etching rate of the mask. Then, the relationship between the flow rate of PF3 gas in the process gas used in the STP process and the etching rate of the silicon oxide film was determined. Furthermore, the relationship between the flow rate of PF3 gas in the process gas used in the STP process and the maximum width of the opening formed on the silicon oxide film was determined. Furthermore, the relationship between the flow rate of PF3 gas in the process gas used in the STP process and the selectivity was determined. The relationship between the flow rate of PF3 gas in the process gas and the etching rate of the silicon oxide film is shown below. Figure 8 Furthermore, the relationship between the flow rate of PF3 gas in the treatment gas and the maximum width of the opening formed on the silicon oxide film is shown in [the figure]. Figure 9 Furthermore, the relationship between the flow rate of PF3 gas in the treated gas and the selectivity ratio is shown in the figure. Figure 10 middle.

[0141] like Figure 8 and Figure 10 As shown, it was confirmed that when the processing gas contains phosphorus, i.e., the flow ratio is greater than 0, the etching rate and selectivity of the silicon oxide film increase. Furthermore, as... Figure 10 As shown, it was confirmed that a considerably high selectivity ratio can be obtained when the flow rate of PF3 gas in the processed gas is 15 sccm or more and 60 sccm or less or 50 sccm or less. That is, it was confirmed that a considerably high selectivity ratio can be obtained when the flow rate ratio is 0.075 or more and 0.3 or less or 0.25 or less. Furthermore, as... Figure 8 As shown, it was confirmed that when the flow rate of PF3 gas in the processing gas is 20 sccm or more, that is, when the flow ratio is 0.1 or more, the etching rate is about 1.5 times that when no PF3 is added.

[0142] And, as Figure 9 As shown, it was confirmed that when the process gas contains phosphorus, the maximum width of the opening in the silicon oxide film can be suppressed from decreasing, i.e., the width of the opening in the silicon oxide film locally widens. In particular, it was confirmed that when the flow rate of PF3 gas in the process gas is 50 sccm or more, the local widening of the opening width in the silicon oxide film can be suppressed more significantly.

[0143] Furthermore, in Figure 9 In the diagram, 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 as the etchant increases with the increase of the PF3 gas flow rate, and the increase in etchant leads to an increase in the etching rate (see reference). Figure 8 The vertical etching rate increases with increasing PF3 gas flow rate. However, even with increased PF3 gas flow rate, the maximum width of the recess (opening), though slightly smaller, remains roughly constant up to a flow rate of 15 sccm (7.5%). Above 15 sccm (7.5%), the maximum width of the recess (opening) decreases. Therefore, by using phosphorus-containing gas during etching, lateral etching (Boeing) can be effectively suppressed.

[0144] Regarding the protective film containing PO bonds, the protective film with PO bonds exhibits low volatility (i.e., chemically robust). As the inventors have recognized, the presence of the protective film with PO bonds effectively protects the sidewalls of the recesses in the silicon-containing film from erosion based on ions with relatively low energy. On the other hand, ions incident on the bottom of the recess (opening) have high energy, thus removing (etching) the bottom of the recess even though the protective film is formed at the bottom of the recess. Therefore, the protective film with PO bonds provides selective protection against undesirable sidewall etching. This is because the protective film with PO bonds is chemically robust enough to prevent removal by low-energy ions colliding with the sidewalls at shallow angles. On the other hand, it is because the high-energy ions colliding with the bottom of the recess due to direct impact have sufficiently high energy to etch and remove the protective film with PO bonds at the bottom of the recess. Consequently, while suppressing sidewall erosion, it becomes possible to perform etching with a higher aspect ratio.

[0145] The second experiment conducted to evaluate the method MT will be described below. In the second experiment, multiple sample substrates were prepared. Each sample substrate had a silicon-containing film and a mask disposed on the silicon-containing film. The silicon-containing film was a stack of alternating silicon oxide and silicon nitride films. The mask was a mask formed of an amorphous carbon film. In the second experiment, the process step STP of the method MT was applied to the multiple sample substrates. The processing gas used for each of the multiple sample substrates contained PF3 gas at different flow rates. Another condition of the process STP is shown below. The flow rates of the PF3 gas were 0 sccm, 5 sccm, 20 sccm, and 30 sccm, respectively.

[0146] <Conditions for STP process>

[0147] The gas pressure inside chamber 10: 25 mTorr (3.3 Pa)

[0148] Gases to be processed: Fluorine-containing gases, hydrofluorocarbon gases, halogen-containing gases containing halogen elements other than fluorine, and mixtures of PF3 gases.

[0149] High-frequency power (HF): 40MHz, 5500W

[0150] High-frequency power (LF): 400kHz, 8400W

[0151] Sample substrate temperature (substrate support temperature before etching begins): -30℃

[0152] In Experiment 2, the etching rate of the silicon-containing film, the etching rate of the mask, and the selectivity were determined for each of the multiple sample substrates. The selectivity was obtained by dividing the etching rate of the silicon-containing film by the etching rate of the mask. Then, in Experiment 2, the relationship between the PF3 gas flow rate and the etching rate of the silicon-containing film, the etching rate of the mask, and the selectivity was determined. Figure 11 The diagram shows the relationship between the PF3 gas flow rate determined in Experiment 2 and the etching rate of the silicon-containing film, the etching rate of the mask, and the selectivity. For example... Figure 11 As shown in the results of the second experiment, it was confirmed that even with a low flow rate of PF3 gas added to the processing gas, the etching rate of the silicon-containing film increased. Furthermore, it was confirmed that even with a low flow rate of PF3 gas added to the processing gas, the selectivity also increased.

[0153] The following is for reference. Figure 12 An etching method according to another exemplary embodiment will be described. Figure 12 This is a flowchart of an etching method according to another exemplary embodiment. Figure 12 The etching method shown (hereinafter referred to as "Method MT2") is applicable to substrates having a silicon-containing film. Substrates suitable for Method MT2 include, for example,... Figure 2 The substrate W shown has a silicon-containing film SF. In method MT2, the silicon-containing film SF is etched. The silicon-containing film etched in method MT2 is the silicon-containing film SF described in method MT. As described above, the substrate W to which method MT2 is applied may also have a mask MK and a substrate region UR.

[0154] In method MT2, a plasma processing apparatus is used for etching the silicon-containing film SF. The plasma processing apparatus used in method MT2 is, for example, the plasma processing apparatus 1 described above.

[0155] The following describes the application of plasma processing apparatus 1 in method MT2. Figure 2 The method MT2 will be explained using the substrate W shown as an example. When using the plasma processing apparatus 1, the method MT2 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 by 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 explained.

[0156] In the following description, except Figure 12 In addition, refer to Figure 13 , Figure 14 and Figure 15 . Figure 13 and Figure 14 They are applicable Figure 12 A partially enlarged cross-sectional view of a substrate for an example of the etching method shown. Figure 15 This is an example timing diagram of an etching method according to another exemplary embodiment. Figure 15 In the diagram, the horizontal axis represents time. Figure 15 In, with Figure 7 Similarly, the vertical axis represents the power level of the high-frequency power HF, the electrical bias level, and the supply status of the processing gas. An "L" level for the high-frequency power HF indicates that no high-frequency power HF is supplied or that the power level of the high-frequency power HF is lower than the power level represented by "H". An "L" level for the electrical bias indicates that the electrical bias is not applied to the lower electrode 18 or that the electrical bias level is lower than the level represented by "H". Furthermore, an "ON" state for the processing gas supply status indicates that processing gas is supplied to the chamber 10, and an "OFF" state for the processing gas supply status indicates that the supply of processing gas to the chamber 10 is stopped.

[0157] like Figure 12 As shown, method MT2 begins in process ST21. In process ST21, the substrate W is prepared in chamber 10, similar to process ST1 of method MT.

[0158] In 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 process gas within chamber 10.

[0159] The processing gases used in process ST22 include hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas. The processing gases may also include rare gases. The processing gases may also include halogen-containing gases that are fluorine-free. For example, halogen-containing gases that are fluorine-free contain at least one of Cl2, HBr, and BCl3. The processing gases may also include oxygen-containing gases. For example, oxygen-containing gases contain O2.

[0160] In process ST22, the phosphorus-containing gas used is the phosphorus-containing gas described in combination method MT. In process ST22, the carbon-containing gas includes hydrocarbons (C...). x H y ), hydrofluorocarbons (C) s H t F u ) and fluorocarbons (C v F wAt least one of the following: x, y, s, t, u, v, and w. Wherein, x, y, s, t, u, v, and w are natural numbers. Hydrocarbons, for example, are at least one of CH4, C3H6, etc. Hydrofluorocarbons, for example, are at least one of CH2F2, CHF3, CH3F, C2HF5, and C3H2F4, etc. Fluorocarbons, for example, are at least one of CF4, C2F6, C3F6, C3F8, C4F6, C4F8, and C5F8, etc. When using a carbon-containing gas containing two or more carbon atoms, the protective effect of the sidewalls dividing the openings in the mask MK and the silicon-containing film SF can be further improved.

[0161] In one embodiment, among the processing gases used in step ST22, the flow rate of hydrogen fluoride gas can be the largest among the flow rates of hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas. When the processing gas used in step ST22 includes rare gases, the flow rate of hydrogen fluoride gas can be the largest among the flow rates of all gases in the processing gas except for the rare gases. When the processing gas does not contain rare gases, the ratio of the flow rate of hydrogen fluoride gas to the flow rate of the processing gas can be 50% or more and less than 99%. When the processing gas includes rare gases, the ratio of the flow rate of hydrogen fluoride gas to the flow rate of the processing gas except for the rare gases can be 50% or more and less than 99%. Furthermore, when the processing gas does not contain rare gases, the ratio of the flow rate of phosphorus-containing gas to the flow rate of the processing gas can be 1% or more and less than 20%. When the processing gas includes rare gases, the ratio of the flow rate of phosphorus-containing gas to the flow rate of the processing gas except for the rare gases can be 1% or more and less than 20%. Furthermore, in the processed gas, the proportion of phosphorus-containing gas flow rate in the total flow rate of hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas can be 2% or more. Also, when the processed gas does not contain rare gases, the proportion of carbon-containing gas flow rate to the processed gas flow rate can be greater than 0% and less than 20%; when the processed gas contains rare gases, the proportion of carbon-containing gas flow rate to the flow rate of the processed gas other than rare gases can be greater than 0% and less than 20%.

[0162] In one embodiment, in the processing gas used in step ST22, the proportion of the halogenated gas flow rate in the total flow rate of hydrogen fluoride gas, phosphorus-containing gas, carbon-containing gas, and halogenated gas can be greater than 0% and less than 10%.

[0163] To execute step ST22, the control unit 80 controls the gas supply unit to supply processing gas into the chamber 10. Furthermore, the control unit 80 controls the exhaust device 50 to set the pressure of the gas within the chamber 10 to a specified pressure. Additionally, the control unit 80 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 electrical bias.

[0164] In one embodiment, the temperature of the substrate support 14 (especially the electrostatic chuck 20) ​​in process ST22 can be set to a temperature below 0°C or below -40°C. If the temperature of the substrate W is set to such a temperature, the etching rate of the silicon-containing film SF in process ST22 becomes higher. In process ST22, the control unit 80 can control the cooler unit in order to set the temperature of the substrate support 14.

[0165] In process ST22, such as Figure 13 and Figure 14 As shown, the silicon-containing film SF is etched using halogen chemical species from plasma generated from the processing gas. The halogen chemical species include fluorine chemical species generated from hydrogen fluoride gas. Hydrogen fluoride is a small molecule, and the chemical species generated from it have a small sputtering effect on the mask MK, thus suppressing the etching of the mask MK. Therefore, the plasma generated from hydrogen fluoride gas can etch the silicon-containing film SF while suppressing the etching of the mask MK. Furthermore, the plasma generated from hydrogen fluoride gas can increase the etching rate of the silicon-containing film SF. Additionally, chemical species generated from carbon-containing gas protect the mask MK. The greater the number of carbon atoms in the molecules contained in the carbon-containing gas, the higher the protection effect on the mask MK. Furthermore, the plasma generated from phosphorus-containing gas can suppress the etching of the mask MK. Moreover, with phosphorus chemical species generated from phosphorus-containing gas present on the surface of the substrate W, it promotes the adsorption of chemical species generated from hydrogen fluoride, i.e., the etchant, onto the substrate W. That is, when phosphorus chemical species generated from phosphorus-containing gas are present on the surface of substrate W, etchant is supplied to the bottom of the opening (recess), thereby increasing the etching rate of the silicon-containing film SF. Therefore, according to method MT2, it becomes possible to selectively increase the etching rate and etching during plasma etching of the silicon-containing film SF. Furthermore, when the phosphorus-containing gas contained in the processing gas contains the aforementioned halogen element and / or when the processing gas contains the aforementioned halogen-containing gas, the etching rate of the silicon-containing film SF can be further increased. Additionally, even when hydrogen-containing gas and fluorine-containing gas are used instead of hydrogen fluoride gas in conjunction with the phosphorus-containing gas, the same effect as that achieved by using hydrogen fluoride gas can be achieved. The hydrogen-containing gas is, for example, H2 gas and / or hydrofluorocarbon gas. The fluorine-containing gas is, for example, fluorocarbon gas.

[0166] Furthermore, in process ST22, phosphorus chemical species (ions and / or free radicals) are supplied to the substrate W from the plasma generated by phosphorus-containing gas. For example... Figure 13 As shown, phosphorus chemical species can form a phosphorus-containing protective film PF on the surface of the substrate W. The protective film PF may also contain carbon and / or hydrogen contained in the process gas. In one embodiment, the protective film PF may also contain oxygen contained in the process gas or in the silicon-containing film SF. In one embodiment, the protective film PF may contain phosphorus-oxygen bonds.

[0167] Instead of forming a protective film (PF), or in addition to forming a protective film (PF), phosphorus chemical species can form bonds between the elements contained in the silicon-containing film (SF) and phosphorus on the sidewalls that divide the openings in the silicon-containing film (SF). In the case where the silicon-containing film (SF) includes a silicon oxide film, phosphorus chemical species form phosphorus-oxygen bonds on the sidewalls of the silicon-containing film (SF). Figure 14 In this context, phosphorus is represented by a circle surrounding the letter "P". In process ST22, the sidewalls of the silicon-containing SF film are deactivated (or passivated) due to the presence of phosphorus chemical species. That is, passivation of the sidewalls of the silicon-containing SF film is performed.

[0168] Therefore, according to method MT2, the etching of the sidewalls of the silicon-containing SF and the lateral expansion of the opening of the silicon-containing SF can be suppressed.

[0169] Furthermore, when the mask MK contains carbon, phosphorus chemical species can form carbon-phosphorus bonds on the surface of the mask MK. The carbon-phosphorus bonds have a higher bonding energy than the carbon-to-carbon bonds within the mask MK. Therefore, according to method MT2, the mask MK is protected during plasma etching of the silicon-containing film SF.

[0170] like Figure 15 As shown, in process ST22, it can be compared with the reference. Figure 7 In the process STP described herein, a continuous wave or pulsed wave of high-frequency power HF is supplied in the same manner as the continuous wave or pulsed wave of high-frequency power HF. Furthermore, in process ST22, it is possible to use the reference... Figure 7 The continuous or pulsed wave of electrical bias in the STP process described herein is supplied in the same way as the continuous or pulsed wave of electrical bias.

[0171] That is, in one embodiment, such as Figure 15As shown by the dashed lines, the electrically biased pulse wave described above can be applied from the bias power supply 64 to the lower electrode 18 in process ST22. In other words, when plasma generated from the process gas is present in the chamber 10, the electrically biased pulse wave can be applied from the bias power supply 64 to the lower electrode 18. In this embodiment, the etching of the silicon-containing film SF in process ST22 is mainly generated during period H within the period of the electrically biased pulse wave. Furthermore, the formation and / or passivation treatment of the protective film PF in process ST22 is mainly generated during period L within the period of the electrically biased pulse wave.

[0172] In one implementation, such as Figure 15 As shown by the dashed line, the aforementioned high-frequency power (HF) pulse wave can be supplied in process ST22. For example... Figure 15 As shown, the period of a high-frequency power (HF) pulse wave can be synchronized with the period of an electrically biased pulse wave. For example... Figure 15 As shown, the H-period in the period of the high-frequency power (HF) pulse wave can be synchronized with the H-period in the period of the electrically biased pulse wave. Alternatively, the H-period in the period of the HF pulse wave can be unsynchronized with the H-period in the period of the electrically biased pulse wave. The duration of the H-period in the period of the HF pulse wave can be the same as or different from the duration of the H-period in the period of the electrically biased pulse wave.

[0173] The following describes various experiments conducted to evaluate method MT2. These experiments are not intended to limit the scope of this invention.

[0174] (Experiments 3 to 6)

[0175] In experiments 3 through 6, samples with the same characteristics as were prepared. Figure 2 Multiple sample substrates with the same structure as the substrate W shown are presented. Each sample substrate has a silicon-containing film and a mask disposed on the silicon-containing film. The silicon-containing film is a multilayer film having multiple alternating layers of silicon oxide films and multiple silicon nitride films. The mask is a mask formed of an amorphous carbon film. In each of experiments 3 to 6, plasma generated from a process gas using plasma processing apparatus 1 was used to etch the silicon-containing film of the sample substrate. The process gas used in experiment 3 included H2 gas, hydrofluorocarbon gas, fluorocarbon gas, fluorine-containing gas, and halogen-containing gas. In addition to the process gas in experiment 3, the process gas used in experiment 4 also included PF3 gas. The process gas used in experiment 5 included hydrogen fluoride gas, fluorocarbon gas, and oxygen gas. The process gas used in experiment 6 included hydrogen fluoride gas, fluorocarbon gas, and PF3 gas. Other conditions for each of experiments 3 to 6 are shown below.

[0176] <Other conditions for experiments 3 through 6>

[0177] The gas pressure inside chamber 10: 27 mTorr (3.6 Pa)

[0178] High-frequency power HF (continuous wave): 40MHz, 4400W

[0179] High-frequency power LF (continuous wave): 400kHz, 6000W

[0180] Temperature of substrate support 14: -40℃

[0181] In experiments 3 through 6, the etching rate, selectivity, and maximum width of the opening (Boeing CD) of the silicon-containing film were determined from the etching results. The selectivity was obtained by dividing the etching rate of the silicon-containing film by the etching rate of the mask. The etching rates of the silicon-containing film in experiments 3 through 6 were 310 nm / min, 336 nm / min, 296 nm / min, and 597 nm / min, respectively. The selectivity in experiments 3 through 6 were 3.24, 4.1, 6.52, and 7.94, respectively. The Boeing CDs in experiments 3 through 6 were 106 nm, 104 nm, 128 nm, and 104 nm, respectively. The results from experiments 3 through 6 confirm that, compared to experiments 3 and 5, experiments 4 and 6 achieved both higher etching rates and higher selectivity, and also yielded smaller Boeing CDs. In particular, in experiment 6, an etching rate approximately twice that of experiment 3 was achieved. Therefore, it was confirmed that using a processing gas containing hydrogen fluoride, carbon, and phosphorus during plasma etching of silicon-containing films can improve both the etching rate and etching selectivity. Furthermore, it was confirmed that using a processing gas containing hydrogen fluoride, carbon, and phosphorus during plasma etching of silicon-containing films can suppress the lateral expansion of openings in the silicon-containing films.

[0182] (Experiment 7)

[0183] In Experiment 7, multiple sample substrates identical to those prepared in Experiments 3 through 6 were prepared. In Experiment 7, plasma was generated from a processing gas using plasma processing apparatus 1 to etch the silicon-containing films on the multiple sample substrates. The processing gas used in Experiment 7 included hydrogen fluoride gas and fluorocarbon gas. In Experiment 7, the flow rates of PF3 gas in each of the processing gases used for the multiple sample substrates were different. Specifically, the flow rate ratio of PF3 gas was the ratio of the PF3 gas flow rate to the flow rate of the processing gas. Other conditions in Experiment 7 were the same as those in Experiments 3 through 6.

[0184] In Experiment 7, the etching rate of the silicon-containing film was determined from the etching results of the silicon-containing film on multiple sample substrates. Then, the relationship between the PF3 gas flow rate and the etching rate of the silicon-containing film was calculated. The results are presented below. Figure 16 In the middle. For example Figure 16 As shown, it has been confirmed that a high etching rate can be obtained as long as the ratio of the flow rate of PF3 gas to the flow rate of the processing gas is 2% or more (or 2.5% or more). That is, it has been confirmed that a high etching rate can be obtained as long as the flow rate of phosphorus-containing gas is 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.

[0185] (Experiments 8-11)

[0186] In experiments 8 and 9, multiple substrates each having a silicon oxide film were prepared. In experiments 8 and 9, plasma was generated from a process gas using plasma processing apparatus 1 to etch the silicon oxide films on the multiple sample substrates. In experiments 8 and 9, the temperatures of the substrate supports 14 during etching of the silicon oxide films on the multiple sample substrates were different. In experiments 10 and 11, multiple substrates each having a silicon nitride film were prepared. In experiments 10 and 11, plasma was generated from a process gas using plasma processing apparatus 1 to etch the silicon nitride films on the multiple sample substrates. In experiments 10 and 11, the temperatures of the substrate supports 14 during etching of the silicon nitride films on the multiple sample substrates were different. The process gases used in experiments 8 through 11 included hydrogen fluoride gas and fluorocarbon gas. The flow rate of PF3 gas was 2.5% of the flow rate of the process gas used in experiments 8 and 10. The processing gases used in experiments 9 and 11 did not contain PF3 gas. The other conditions for experiments 8 through 11 were the same as the corresponding conditions for experiments 3 through 6.

[0187] In experiments 8 and 9, the etching rate of the silicon oxide film was determined from the etching results of the silicon oxide film on each of the multiple 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 on each of the multiple sample substrates. The relationship between the temperature of the substrate support 14 set in experiments 8 to 11 and the obtained etching rate is shown below. Figure 17 In. Figure 17 In the text, explanatory notes No. 8, No. 9, No. 10, and No. 11 refer to the results of experiments 8 through 11, respectively. For example... Figure 17As shown, in Experiment 8, where the processing gas contained PF3 gas, the etching rate of the silicon oxide film was confirmed to be higher than that in Experiment 9, where a processing gas without PF3 gas was used. Furthermore, the results of Experiment 8 confirmed that by setting the temperature of the substrate support 14 below 0°C when using a processing gas containing PF3 gas, the etching rate of the silicon oxide film became even higher. Moreover, it was confirmed that by setting the temperature of the substrate support 14 below -40°C when using a processing gas containing PF3 gas, the etching rate of the silicon oxide film significantly increased.

[0188] (Experiments 12 and 13)

[0189] In Experiment 12, plasma processing apparatus 1 was used to generate plasma from a processing gas consisting of a mixture of hydrogen fluoride and argon to etch the silicon oxide film. In Experiment 13, plasma processing apparatus 1 was used to generate plasma from a processing gas consisting of a mixture of hydrogen fluoride, argon, and PF3 to etch the silicon oxide film. In both Experiments 12 and 13, the silicon oxide film was etched while varying the temperature of the electrostatic chuck 20. In both Experiments 12 and 13, a quadrupole mass spectrometer was used to determine the amounts of hydrogen fluoride (HF) and SiF3 in the gas phase during the etching of the silicon oxide film. Figure 18 (a) and Figure 18 (b) shows the results of experiment 12 and experiment 13. Figure 18 (a) shows the relationship between the temperature of the electrostatic chuck 20 and the amounts of hydrogen fluoride (HF) and SiF3 during the etching of the silicon oxide film in Experiment 12. Furthermore, Figure 18 (b) shows the relationship between the temperature of the electrostatic chuck 20 during etching of the silicon oxide film in Experiment 13 and the amounts of hydrogen fluoride (HF) and SiF3, respectively.

[0190] like Figure 18 As shown in (a), in Experiment 12, when the temperature of the electrostatic chuck 20 was approximately -60°C or lower, the amount of hydrogen fluoride (HF) as the etchant decreased, while the amount of SiF3, the reaction product generated by etching the silicon oxide film, increased. That is, in Experiment 12, when the temperature of the electrostatic chuck 20 was approximately -60°C or lower, the amount of etchant used to etch the silicon oxide film increased. On the other hand, as... Figure 18As shown in (b), in Experiment 13, when the temperature of the electrostatic chuck 20 was below 20°C, the amount of hydrogen fluoride (HF) decreased while the amount of SiF3 increased. That is, in Experiment 13, when the temperature of the electrostatic chuck 20 was below 20°C, the amount of etchant used to etch the silicon oxide film increased. The processing gas used in Experiment 13 differed from the processing gas used in Experiment 12 in that it contained PF3 gas. Therefore, in Experiment 13, when etching the silicon oxide film, phosphorus chemical species were formed on the surface of the silicon oxide film. Therefore, it can be understood that when phosphorus chemical species are present on the surface of the silicon oxide film, even at a relatively high temperature below 20°C, etchant adsorption onto the silicon oxide film is promoted. Thus, it was confirmed that when phosphorus chemical species are present on the surface of the substrate, etchant supply to the bottom of the opening (recess) is promoted, thereby increasing the etching rate of the silicon-containing film.

[0191] The following describes experiments 14 through 16 conducted to evaluate methods MT and MT2. In experiments 14 through 16, plasma processing apparatus 1 was used to generate plasmas with different processing gases. The processing gases used in experiment 14 included hydrogen-containing gas, fluorine-containing gas, halogen-containing gas containing halogen elements other than fluorine, hydrofluorocarbon gas, fluorocarbon gas, and hydrocarbon gas. The processing gases used in experiment 15 included hydrofluorocarbon gas, fluorine-containing gas, and halogen-containing gas containing halogen elements other than fluorine. The processing gases used in experiment 16 included hydrogen fluoride gas and fluorocarbon gas. In each of experiments 14 through 16, a quadrupole mass spectrometer was used to determine the amount of chemical species in the gas phase plasma within chamber 10. The results showed that, in each of experiments 14 through 16, the most abundant chemical species was hydrogen fluoride. Specifically, the amounts of hydrogen fluoride measured in experiments 14 through 16 were 35.5%, 45.5%, and 66.7%, respectively. This confirms that when the process gas contains hydrogen fluoride, the amount of hydrogen fluoride in the plasma becomes the highest.

[0192] The above descriptions of various exemplary embodiments are not intended to limit the scope of these embodiments. Various additions, omissions, substitutions, and modifications are possible. Furthermore, elements from different embodiments can be combined to form other embodiments.

[0193] For example, the plasma processing apparatus used in each of method MT and method MT2 can be a capacitively coupled plasma processing apparatus other than plasma processing apparatus 1. Alternatively, the plasma processing apparatus used in each of method MT and method MT2 can 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.

[0194] Furthermore, in addition to a bias power supply 64 that supplies high-frequency power LF to the lower electrode 18, the plasma processing apparatus may also have another bias power supply configured to intermittently or periodically apply pulses of negative polarity DC voltage to the lower electrode 18.

[0195] Furthermore, the disclosed implementation methods also include the following items (A1) to (A17), (B1) to (B92), and (C1) to (C19).

[0196] (A1). An etching method comprising: a step of preparing a substrate within a cavity of a plasma processing apparatus, the substrate comprising a silicon-containing film; and

[0197] The silicon-containing film is etched by a process in which chemical species from a plasma formed from a process gas within the chamber are used to etch the silicon-containing film, the process gas containing halogens and phosphorus.

[0198] (A2). The etching method according to (A1) further includes a step of forming a protective film on the sidewall surface that divides the opening formed by the etching, the protective film containing phosphorus contained in the processing gas.

[0199] (A3). According to the etching method described in (A2), the etching process and the protective film formation process occur simultaneously.

[0200] (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.

[0201] (A5). The etching method according to any one of (A1) to (A4), wherein the processing gas further comprises carbon and hydrogen.

[0202] (A6). The etching method according to (A5), wherein the processing gas comprises H2, HF, and C. x H y CH x F yOr at least one of NH3 as the hydrogen-containing molecule, wherein x and y are natural numbers.

[0203] (A7). The etching method according to any one of (A1) to (A6), wherein the halogen element is fluorine.

[0204] (A8). The etching method according to any one of (A1) to (A7), wherein the processing gas further comprises oxygen.

[0205] (A9). The etching method according to any one of (A1) to (A8), wherein the silicon-containing film is a silicon-containing dielectric film.

[0206] (A10). The etching method according to any one of (A1) to (A9), wherein the silicon-containing film comprises at least one of a silicon oxide film, a silicon nitride film, or a silicon film.

[0207] (A11). The etching method according to any one of (A1) to (A8), wherein the silicon-containing film comprises two or more silicon-containing films having different types of films from each other.

[0208] (A12). According to the etching method described in (A11), the two or more silicon-containing films include silicon oxide films and silicon nitride films.

[0209] (A13). According to the etching method described in (A11), the two or more silicon-containing films include silicon oxide films and silicon films.

[0210] (A14). According to the etching method described in (A11), the two or more silicon-containing films include a silicon oxide film, a silicon nitride film, and a silicon film.

[0211] (A15). The etching method according to any one of (A1) to (A14), wherein the substrate further comprises a mask disposed on the silicon-containing film.

[0212] (A16). The etching method according to any one of (A1) to (A15), wherein, at the start of the etching process, the temperature of the substrate is set to a temperature below 0°C.

[0213] (A17). A plasma processing apparatus comprising:

[0214] Chamber;

[0215] A substrate support configured to support a substrate within the cavity;

[0216] A gas supply unit configured to supply a processing gas for etching a silicon-containing film into the chamber, the processing gas containing halogen elements and phosphorus; and

[0217] A high-frequency power supply configured to generate high-frequency power to generate plasma from the process gas within the chamber.

[0218] (B1). An etching method comprising:

[0219] The process of preparing a substrate within a plasma processing apparatus chamber, the substrate comprising a silicon-containing film; and

[0220] The silicon-containing film is etched using chemical species derived from plasma formed from a process gas within the chamber, the process gas containing halogens and phosphorus.

[0221] The processing gas comprises a first gas that does not contain phosphorus and a second gas that contains phosphorus.

[0222] The flow ratio, which is the ratio of the flow rate of the second gas to the flow rate of the first gas, is greater than 0 and less than 0.5.

[0223] (B2). The etching method according to (B1), wherein the flow rate ratio is 0.075 or higher and 0.3 or lower.

[0224] (B3). The etching method according to (B1), wherein the flow rate ratio is 0.1 or more and 0.25 or less.

[0225] (B4). The etching method according to any one of (B1) to (B3), wherein the processing gas contains PF3 as the phosphorus-containing molecule.

[0226] (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.

[0227] (B6). The etching method according to any one of (B1) to (B5), wherein the processing gas further comprises carbon and hydrogen.

[0228] (B7). The etching method according to (B6), wherein the processing gas comprises H2, HF, and C. x H y CH x F y Or at least one of NH3 as the hydrogen-containing molecule, wherein x and y are natural numbers.

[0229] (B8). The etching method according to any one of (B1) to (B7), wherein the halogen element is fluorine.

[0230] (B9). The etching method according to any one of (B1) to (B8), wherein the processing gas contains fluorocarbons as molecules containing halogen elements.

[0231] (B10). The etching method according to any one of (B1) to (B9), wherein the processing gas further comprises oxygen.

[0232] (B11). The etching method according to any one of (B1) to (B9), wherein the processing gas does not contain oxygen.

[0233] (B12). The etching method according to any one of (B1) to (B11), wherein, in the etching process, a protective film is formed on the sidewall surface that divides the opening formed by the etching.

[0234] (B13). The etching method according to (B12), wherein the protective film comprises phosphorus-oxygen bonds.

[0235] (B14). According to the etching method described in (B13), the protective film further comprises phosphorus-silicon bonding.

[0236] (B15). The etching method according to any one of (B1) to (B14), wherein, at the start of the etching process, the temperature of the substrate is set to a temperature below 0°C.

[0237] (B16). The etching method according to any one of (B1) to (B15), wherein, during the etching process, a high-frequency bias power having a power level of 2 kW or more is supplied to the lower electrode within the substrate support supporting the substrate.

[0238] (B17). The etching method according to (B16), wherein the power level is 10kW or higher.

[0239] (B18). An etching method comprising:

[0240] The process of preparing a substrate within a plasma processing apparatus chamber, the substrate comprising a silicon-containing film;

[0241] The silicon-containing film is etched using chemical species derived from a plasma formed from a process gas within the chamber, the process gas comprising halogens and phosphorus; and

[0242] The process of forming a protective film containing the bonds of phosphorus and oxygen contained in the processing gas on the sidewall surface that divides the opening formed by the etching.

[0243] (B19). According to the etching method described in (B18), the etching process and the protective film formation process occur simultaneously.

[0244] (B20). According to the etching method described in (B18), the etching process and the protective film formation process are performed independently of each other.

[0245] (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.

[0246] (B22). The etching method according to any one of (B18) to (B21), wherein, in order to perform the etching step and the protective film formation step, an electrically biased pulse wave is applied to a lower electrode in a substrate support supporting the substrate, wherein the electrical bias is a pulse wave of high-frequency bias power or negative polarity DC voltage.

[0247] (B23). According to the etching method described in (B22), in the etching process, the high-frequency bias power applied to the lower electrode has a power level of 2 kW or more.

[0248] (B24). The etching method according to (B23), wherein the power level is 10kW or higher.

[0249] (B25). The etching method according to any one of (B18) to (B24), wherein the plasma is generated using a pulse wave of high-frequency power.

[0250] (B26). The etching method according to any one of (B18) to (B25), wherein the processing gas comprises a first gas that does not contain phosphorus and a second gas that contains phosphorus.

[0251] (B27). The etching method according to (B26), wherein the first gas and the second gas are alternately supplied to the chamber.

[0252] (B28). The etching method according to (B26), wherein the flow ratio of the flow rate of the second gas to the flow rate of the first gas is greater than 0 and less than 0.5.

[0253] (B29). The etching method according to (B28), wherein the flow rate ratio is 0.075 or higher and 0.3 or lower.

[0254] (B30). The etching method according to (B28), wherein the flow rate ratio is 0.1 or more and 0.25 or less.

[0255] (B31). The etching method according to any one of (B18) to (B30), wherein the protective film further comprises phosphorus-silicon bonding.

[0256] (B32). The etching method according to any one of (B18) to (B31), wherein the processing gas contains PF3 as the phosphorus-containing molecule.

[0257] (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 or PBr5 as the phosphorus-containing molecule.

[0258] (B34). The etching method according to any one of (B18) to (B33), wherein the processing gas further comprises carbon and hydrogen.

[0259] (B35). The etching method according to (B34), wherein the processing gas comprises H2, HF, and C. x H y CH x F y Or at least one of NH3 as the hydrogen-containing molecule, wherein x and y are natural numbers.

[0260] (B36). The etching method according to any one of (B18) to (B35), wherein the halogen element is fluorine.

[0261] (B37). The etching method according to any one of (B18) to (B36), wherein the processing gas contains fluorocarbons as molecules containing halogen elements.

[0262] (B38). The etching method according to any one of (B18) to (B37), wherein the oxygen is provided from the silicon-containing film.

[0263] (B39). The etching method according to (B38), wherein the processing gas does not contain oxygen.

[0264] (B40). The etching method according to any one of (B18) to (B37), wherein the processing gas further comprises oxygen.

[0265] (B41). The etching method according to any one of (B18) to (B40), wherein, at the start of the etching process, the temperature of the substrate is set to a temperature below 0°C.

[0266] (B42). An etching method comprising:

[0267] The process of preparing a substrate within a plasma processing apparatus chamber, the substrate comprising a silicon-containing film;

[0268] The process of generating plasma from a processing gas containing halogen elements and phosphorus within the chamber; and

[0269] The process of applying an electrically biased pulse wave to the lower electrode of the substrate support that supports the substrate when the plasma is present in the chamber.

[0270] The electrical bias is a pulse wave of high-frequency bias power or negative polarity DC voltage.

[0271] (B43). According to the etching method of (B42), the pulse wave of the electrical bias is applied to the lower electrode by alternately switching the supply and cessation of the electrical bias to the lower electrode.

[0272] (B44). According to the etching method of (B42), the electrical bias pulse wave is applied to the lower electrode by increasing or decreasing the level of the electrical bias.

[0273] (B45). The etching method according to any one of (B42) to (B44), wherein the electrically biased pulse wave is periodically applied to the lower electrode.

[0274] The period of the electrically biased pulse wave includes two periods.

[0275] The level of the electrically biased pulse wave during one of the two periods is higher than the level of the electrically biased pulse wave during the other of the two periods.

[0276] The proportion of a period in the cycle, i.e., the duty cycle, is more than 1% and less than 80%.

[0277] (B46). The etching method according to (B45), wherein the frequency of the period is defined as 5 Hz or more and 100 kHz or less.

[0278] (B47). The etching method according to (B45) or (B46), wherein the electrical bias has a power level of 2 kW or more during the one period.

[0279] (B48). The etching method according to (B47), wherein the power level is 10kW or higher.

[0280] (B49). The etching method according to any one of (B42) to (B48), wherein the processing gas comprises a first gas that does not contain phosphorus and a second gas that contains phosphorus.

[0281] (B50). According to the etching method of (B49), the first gas and the second gas are alternately supplied to the chamber.

[0282] (B51). According to the etching method of (B50), in the period of the pulse wave, the period of supplying the first gas at least partially overlaps with the period of applying the electrical bias to the lower electrode.

[0283] (B52). According to the etching method described in (B49), the flow ratio of the flow rate of the second gas to the flow rate of the first gas is greater than 0 and less than 0.5.

[0284] (B53). The etching method according to (B52), wherein the flow rate ratio is 0.075 or higher and 0.3 or lower.

[0285] (B54). The etching method according to (B52), wherein the flow rate ratio is 0.1 or more and 0.25 or less.

[0286] (B55). The etching method according to any one of (B42) to (B54), wherein the step of applying an electrically biased pulse wave includes: a stage of etching the silicon-containing film to form an opening; and a stage of forming a protective film on a sidewall surface that divides the opening, wherein the stage of forming the opening and the stage of forming the protective film are performed independently of each other.

[0287] (B56). The etching method according to (B55), wherein the protective film comprises phosphorus-oxygen bonds.

[0288] (B57). According to the etching method described in (B56), the protective film further comprises phosphorus-silicon bonding.

[0289] (B58). The etching method according to any one of (B42) to (B57), wherein the processing gas contains PF3 as the phosphorus-containing molecule.

[0290] (B59). The 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.

[0291] (B60). The etching method according to any one of (B42) to (B59), wherein the processing gas further comprises carbon and hydrogen.

[0292] (B61). The etching method according to (B60), wherein the processing gas comprises H2, HF, and C. x H y CH x F y C x H y F z Or at least one of NH3 as the hydrogen-containing molecule, wherein x, y and z are natural numbers.

[0293] (B62). The etching method according to any one of (B42) to (B61), wherein the halogen element is fluorine.

[0294] (B63). The etching method according to any one of (B42) to (B62), wherein the processing gas contains fluorocarbons as molecules containing halogen elements.

[0295] (B64). The etching method according to any one of (B42) to (B63), wherein the processing gas further comprises oxygen.

[0296] (B65). The etching method according to any one of (B42) to (B63), wherein the processing gas does not contain oxygen.

[0297] (B66). The etching method according to any one of (B42) to (B65), wherein, at the start of the etching process, the temperature of the substrate is set to a temperature below 0°C.

[0298] (B67). An etching method comprising:

[0299] The process of preparing a substrate in the chamber of a plasma processing apparatus, the substrate comprising two or more silicon-containing films having different types of films from each other;

[0300] The process of setting the substrate to below 0°C; and

[0301] The silicon-containing film is etched by a process in which chemical species from a plasma formed from a process gas within the chamber are used to etch the silicon-containing film, the process gas comprising PF3.

[0302] (B68). The etching method according to (B67), wherein the silicon-containing film comprises a silicon oxide film.

[0303] (B69). The etching method according to (B67) or (B68), wherein the processing gas comprises a first gas that does not contain phosphorus and PF3 contains a second gas.

[0304] (B70). According to the etching method described in (B69), the flow ratio of the flow rate of the second gas to the flow rate of the first gas is greater than 0 and less than 0.5.

[0305] (B71). The etching method according to (B70), wherein the flow rate ratio is 0.075 or higher and 0.3 or lower.

[0306] (B72). The etching method according to (B70), wherein the flow rate ratio is 0.1 or more and 0.25 or less.

[0307] (B73). The etching method according to any one of (B67) to (B72), wherein the processing gas further comprises a fluorocarbon.

[0308] (B74). The etching method according to any one of (B67) to (B73), wherein the processing gas further comprises carbon and hydrogen.

[0309] (B75). The etching method according to (B74), wherein the processing gas comprises H2, HF, and C. x H y CH x F y Or at least one of NH3 as the hydrogen-containing molecule, wherein x and y are natural numbers.

[0310] (B76). The etching method according to any one of (B67) to (B75), wherein the processing gas further comprises oxygen.

[0311] (B77). The etching method according to any one of (B67) to (B75), wherein the processing gas does not contain oxygen.

[0312] (B78). The etching method according to any one of (B67) to (B77), wherein, in the etching process, a protective film is formed on the sidewall surface that divides the opening formed by the etching.

[0313] (B79). The etching method according to any one of (B67) to (B77), wherein the etching step includes: a stage of etching the silicon-containing film to form an opening; and a stage of forming a protective film on a sidewall surface that divides the opening, wherein the stage of forming the opening and the stage of forming the protective film are performed independently of each other.

[0314] (B80). The etching method according to (B78) or (B79), wherein the protective film comprises phosphorus-oxygen bonds.

[0315] (B81). According to the etching method described in (B80), the protective film further comprises phosphorus-silicon bonding.

[0316] (B82). The etching method according to any one of (B67) to (B81), wherein, during the etching process, a high-frequency bias power having a power level of 2 kW or more is supplied to the lower electrode within the substrate support supporting the substrate.

[0317] (B83). The etching method according to (B82), wherein the power level is 10kW or higher.

[0318] (B84). The etching method according to any one of (B67) to (B83), wherein, during the etching process, a pulse wave of negative DC voltage is supplied to a lower electrode within a substrate support supporting the substrate.

[0319] (B85). The etching method according to any one of (B1) to (B84), wherein the silicon-containing film is a silicon-containing dielectric film.

[0320] (B86). The etching method according to any one of (B1) to (B85), wherein the silicon-containing film comprises at least one of a silicon oxide film, a silicon nitride film, or a silicon film.

[0321] (B87). The etching method according to any one of (B1) to (B84), wherein the silicon-containing film comprises two or more silicon-containing films having different types of films from each other.

[0322] (B88). According to the etching method described in (B87), the two or more silicon-containing films include silicon oxide films and silicon nitride films.

[0323] (B89). According to the etching method of (B87), wherein the two or more silicon-containing films comprise a plurality of silicon oxide films and a plurality of silicon nitride films stacked alternately.

[0324] (B90). According to the etching method described in (B87), wherein the two or more silicon-containing films include a silicon oxide film and a silicon film.

[0325] (B91). According to the etching method described in (B87), wherein the two or more silicon-containing films comprise multiple silicon oxide films and multiple polycrystalline silicon films stacked alternately.

[0326] (B92). The etching method according to any one of (B1) to (B91), wherein the substrate further comprises a mask disposed on the silicon-containing film.

[0327] (C1). An etching method comprising:

[0328] (a) A process of preparing a substrate containing a silicon film and a mask within a plasma processing apparatus chamber; and

[0329] (b) A process of etching the silicon-containing film by generating plasma from a process gas in the chamber, the process gas comprising hydrogen fluoride gas, phosphorus-containing gas and carbon-containing gas.

[0330] (C2). According to the etching method described in (C1), 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.

[0331] (C3). The etching method according to (C1), wherein the processing gas further comprises a rare gas.

[0332] Of all the gases in the processing gas except for the rare gases, the hydrogen fluoride gas has the highest flow rate.

[0333] (C4). The etching method according to any one of (C1) to (C3), wherein, in (b), the temperature of the substrate support supporting the substrate is set to a temperature below 0°C.

[0334] (C5). According to the etching method of (C4), wherein in (b), the temperature of the substrate support supporting the substrate is set to a temperature below -40°C.

[0335] (C6). The etching method according to any one of (C1) to (C5), wherein the phosphorus-containing gas contains a halogen element.

[0336] (C7). The etching method according to (C6), wherein the halogen element is a halogen element other than fluorine.

[0337] (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 flow rate of the phosphorus-containing gas, and the flow rate of the carbon-containing gas is 2% or more.

[0338] (C9). The etching method according to any one of (C1) to (C8), wherein the processing gas further comprises a halogen-containing gas that is free of fluorine.

[0339] (C10). According to the etching method of (C9), the proportion of the flow rate of the halogen-containing gas in the total flow rate of the hydrogen fluoride gas, the flow rate of the phosphorus-containing gas, the flow rate of the carbon-containing gas and the flow rate of the halogen-containing gas is greater than 0% and less than 10%.

[0340] (C11). The etching method according to any one of (C1) to (C10), wherein the silicon-containing film comprises a silicon oxide film.

[0341] (C12). According to the etching method of (C11), the silicon-containing film further includes a silicon nitride film.

[0342] (C13). A processing gas for plasma etching of a silicon oxide film, said processing gas comprising hydrogen fluoride gas, phosphorus-containing gas and carbon-containing gas.

[0343] (C14). The processing gas according to (C13), wherein, among the flow rates of the hydrogen fluoride gas, the phosphorus-containing gas, and the carbon-containing gas, the flow rate of the hydrogen fluoride gas is the largest.

[0344] (C15). The processing gas according to (C13), wherein the processing gas further comprises a rare gas, and of all the gases in the processing gas other than the rare gas, the flow rate of the hydrogen fluoride gas is the largest.

[0345] (C16). The processing gas according to any one of (C13) to (C15), wherein the phosphorus-containing gas contains a halogen element.

[0346] (C17). The processed gas according to (C16), wherein the halogen element is a halogen element other than fluorine.

[0347] (C18). The processing gas according to any one of (C13) to (C15), wherein the proportion of the flow rate of the phosphorus-containing gas in the total flow rate of the hydrogen fluoride gas, the flow rate of the phosphorus-containing gas, and the flow rate of the carbon-containing gas is 2% or more.

[0348] (C19). A plasma processing apparatus comprising:

[0349] Chamber;

[0350] A substrate support is disposed within the cavity;

[0351] A gas supply unit configured to supply a processing gas containing hydrogen fluoride gas, phosphorus-containing gas, and carbon-containing gas into the chamber;

[0352] A plasma generation unit configured to generate plasma from the processed gas; and

[0353] The control unit is configured to control the gas supply unit to supply the processing gas into the chamber for etching the silicon-containing film of the substrate supported by the substrate holder, and to control the plasma generation unit to generate plasma from the processing gas in the chamber.

[0354] As can be understood from the above description, various embodiments of the present invention have been described in this specification for illustrative purposes, and various modifications can be made without departing from the scope and spirit of the invention. Therefore, the various embodiments disclosed in this specification are not limited, and the true scope and spirit are indicated by the appended claims.

[0355] Symbol Explanation

[0356] 1-Plasma processing device, 10-Cavity, 14-Substrate support, 80-Control unit, W-Substrate, SF-Silicon-containing film.

Claims

1. A plasma processing apparatus for etching silicon-containing films, comprising: chamber; A substrate support is disposed within the cavity; A gas supply unit configured to supply a processing gas containing hydrogen fluoride gas and phosphorus-containing gas into the chamber; A plasma generation unit configured to generate plasma from the processed gas; and The control unit is configured to control the gas supply unit to supply the process gas into the chamber for etching the silicon-containing film of the substrate supported by the substrate support, and to control the plasma generation unit to generate plasma from the process gas in the chamber. The ratio of the flow rate of the second gas to the flow rate of the first gas in the processed gas is greater than 0 and less than 0.

5. The first gas is all gases included in the processing gas except for the phosphorus-containing gas, and the second gas is the phosphorus-containing gas.

2. The plasma processing apparatus of claim 1, wherein, The flow rate of the phosphorus-containing gas is more than 1% and less than 20% of the flow rate of the processing gas other than rare gases.

3. The plasma processing apparatus of claim 1, wherein, The phosphorus-containing gas contains halogens.

4. The plasma processing apparatus of claim 1, wherein, The phosphorus-containing gas contains at least one of PF3, PCl3, PF5, PCl5, POCl3, PH3, PBr3, or PBr5.

5. The plasma processing apparatus of claim 1, wherein, The phosphorus-containing gas contains fluorine.

6. The plasma processing apparatus of claim 1, wherein, The processing gas further includes carbon-containing gas.

7. The plasma processing apparatus of claim 6, wherein, The carbon-containing gas includes at least one of fluorocarbons and hydrofluorocarbons.

8. The plasma processing apparatus of claim 6, wherein, The carbon-containing gas contains at least one of CH2F2, CHF3, CH3F, C2HF5, or C3H2F4.

9. The plasma processing apparatus of claim 6, wherein, The carbon-containing gas includes at least one of CF4, C2F6, C3F6, C3F8, C4F6, C4F8 or C5F8.

10. The plasma processing apparatus of claim 6, wherein, The carbon-containing gas contains two or more carbon atoms.

11. The plasma processing apparatus of claim 1, wherein, The processing gas further comprises a halogen-containing gas that does not contain fluorine.

12. The plasma processing apparatus of claim 11, wherein, The halogen-containing gas that does not contain fluorine is Cl2 gas and / or HBr gas.

13. The plasma processing apparatus of claim 1, wherein, The substrate support includes a lower electrode. The plasma processing device further includes a bias power supply electrically connected to the lower electrode. The bias power supply is configured to periodically apply electrically biased pulse waves to the lower electrode when the plasma is present in the cavity. The electrical bias is a pulse wave of high-frequency bias power or negative polarity DC voltage.

14. The plasma processing apparatus of claim 13, wherein, The frequency of the period of the pulse wave that applies the electrical bias to the lower electrode is defined as being 5 Hz or more and 100 kHz or less.

15. The plasma processing apparatus according to claim 1, further comprising a cooler unit configured to supply a heat exchange medium to a flow path within the lower electrode of the substrate support. The control unit is configured to control the cooler unit to supply the heat exchange medium to the flow path and set the temperature of the substrate support to below 0°C before the plasma is generated.

16. An etching method, comprising: (a) A process of preparing a substrate having a silicon film and a mask in the chamber of the plasma processing apparatus of claim 1; and (b) The process of etching the silicon-containing film by generating plasma from a processing gas in the chamber, the processing gas comprising hydrogen fluoride gas and phosphorus-containing gas.

17. A method of manufacturing an apparatus, comprising etching a silicon-containing film of a substrate by the etching method of claim 16.

18. A computer-readable recording medium storing a program, the recording medium being configured such that, when the program is executed by a processor of a computer in the plasma processing apparatus according to claim 1, the following steps are performed in the plasma processing apparatus: (a) The step of preparing a substrate having a silicon-containing film and a mask within the chamber of the plasma processing apparatus of claim 1; and (b) The process of etching the silicon-containing film by generating plasma from a processing gas in the chamber, the processing gas comprising hydrogen fluoride gas and phosphorus-containing gas.

19. A processing gas for use in the plasma processing apparatus of claim 1, wherein the processing gas is for plasma etching of a silicon-containing film, comprising hydrogen fluoride gas and phosphorus-containing gas.

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