Substrate Processing Method and Substrate Processing Apparatus

Abstract

One illustrative embodiment of the present invention provides a substrate processing method. This substrate processing method comprises: a step for preparing a substrate having a silicon-containing film within a chamber; and a step for etching the silicon-containing film of the substrate by introducing a processing gas, which contains a phosphorus halide gas, an HF gas and at least one gas that is selected from the group consisting of a C4H2F6 gas, a C4H2F8 gas, a C3H2F4 gas and a C3H2F6 gas, into the chamber and generating a plasma.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a substrate processing method and a substrate processing apparatus.

Background Art

[0002] For example, Patent Document 1 discloses a technique for etching a silicon oxide film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for improving an etching rate.

Means for Solving the Problems

[0005] In one exemplary embodiment of the present disclosure, a step of preparing a substrate having a silicon-containing film in a chamber, and introducing a processing gas containing at least one gas selected from the group consisting of C4H2F6 gas, C4H2F8 gas, C3H2F4 gas, and C3H2F6 gas, HF gas, and a phosphorus halide gas into the chamber to generate plasma, and etching the silicon-containing film of the substrate are provided.

Effects of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique for improving an etching rate can be provided.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, each embodiment of the present disclosure will be described.

[0009] In one exemplary embodiment, a substrate processing method is provided. The substrate processing method includes a step of preparing a substrate having a silicon-containing film in a chamber, and a step of introducing a processing gas containing at least one gas selected from the group consisting of C4H2F6 gas, C4H2F8 gas, C3H2F4 gas, and C3H2F6 gas, HF gas, and a phosphorus halide gas into the chamber to generate plasma and etching the silicon-containing film of the substrate.

[0010] In one exemplary embodiment, the phosphorus halide comprises at least one selected from the group consisting of PF3 gas, PF5 gas, POF3 gas, HPF6 gas, PCl3 gas, PCl5 gas, POCl3 gas, PBr3 gas, PBr5 gas, POBr3 gas, and PI3 gas.

[0011] In one exemplary embodiment, the processing gas further comprises at least one selected from the group consisting of a halogen-containing gas, a carbon-containing gas, an oxygen-containing gas, and a nitrogen-containing gas.

[0012] In one exemplary embodiment, the halogen-containing gas is at least one selected from the group consisting of a chlorine-containing gas, a bromine-containing gas, and an iodine-containing gas.

[0013] In one exemplary embodiment, the halogen-containing gas is at least one gas selected from the group consisting of Cl2, SiCl2, SiCl4, CCl4, SiH2Cl2, Si2Cl6, CHCl3, SO2Cl2, BCl3, PCl3, PCl5, POCl3, Br2, HBr, CBr2F2, C2F5Br, PBr3, PBr5, POBr3, BBr3, HI, CF3I, C2F5I, C3F7I, IF5, IF7, I2, and PI3.

[0014] In one exemplary embodiment, the carbon-containing gas is C a H b (where a and b are integers of 1 or more) gas, C c F d (where c and d are integers of 1 or more) gas, and CH e F f (where e and f are integers of 1 or more) gas, and is at least one selected from the group consisting thereof.

[0015] In one exemplary embodiment, the nitrogen-containing gas is at least one selected from the group consisting of NF3 gas, N2 gas, and NH3 gas.

[0016] In one exemplary embodiment, the processing gas further includes an oxygen-containing gas, and the oxygen-containing gas is at least one selected from the group consisting of O2 gas, CO gas, CO2 gas, H2O gas, and H2O2 gas.

[0017] In one exemplary embodiment, the processing gas further includes at least one selected from the group consisting of a boron-containing gas and a sulfur-containing gas.

[0018] In one exemplary embodiment, the processing gas further includes an inert gas.

[0019] In one exemplary embodiment, the silicon-containing film includes at least one selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polysilicon film.

[0020] In one exemplary embodiment, the substrate has a mask made of an organic film or a metal-containing film that defines at least one opening on the silicon-containing film.

[0021] In one exemplary embodiment, the step of etching includes applying an electrical bias to the substrate support in a first period and a second period alternating with the first period, and the electrical bias in the first period is 0 or a first level, and the electrical bias in the second period is a second level greater than the first level.

[0022] In one exemplary embodiment, the step of etching includes supplying high-frequency power for generating plasma to the substrate support or an upper electrode facing the substrate support in a third period and a fourth period alternating with the third period, and the level of the high-frequency power in the third period is 0 or a third level, and the level of the high-frequency power in the fourth period is a fourth level greater than the third level, and at least a part of the second period and the fourth period overlaps.

[0023] In one exemplary embodiment, the electrical bias is a pulsed voltage.

[0024] In one exemplary embodiment, the etching step includes supplying a direct current voltage or low frequency power to an upper electrode facing the substrate support.

[0025] In one exemplary embodiment, the etching step includes a first step of setting the pressure in the chamber to a first pressure and supplying a first electrical bias to the substrate support to etch a silicon-containing film, and a second step of setting the pressure in the chamber to a second pressure and supplying a second electrical bias to the substrate support to etch the silicon-containing film, wherein the first pressure is different from the second pressure and / or the first electrical bias is different from the second electrical bias.

[0026] In one exemplary embodiment, the first pressure is greater than the second pressure.

[0027] In one exemplary embodiment, the absolute value of the magnitude of the first electrical bias is greater than the absolute value of the magnitude of the second electrical bias.

[0028] In one exemplary embodiment, the first step and the second step are alternately repeated.

[0029] In one exemplary embodiment, a substrate processing method is provided. The substrate processing method includes a step of preparing a substrate having a silicon-containing film in a chamber, and a step of introducing a processing gas including C x H y F z (where x is an integer of 2 or more, and y and z are integers of 1 or more), a fluorine-containing gas, and a phosphorus-containing gas into the chamber to generate plasma and etch the silicon-containing film of the substrate.

[0030] In one exemplary embodiment, the fluorine-containing gas is a gas capable of generating HF species in the chamber.

[0031] In one exemplary embodiment, C x H y F z The gas has one or more CF3 groups.

[0032] In one exemplary embodiment, C x H y F z The gas contains at least one selected from the group consisting of C3H2F4 gas, C3H2F6 gas, C4H2F6 gas, C4H2F8 gas, and C5H2F6 gas.

[0033] In one exemplary embodiment, the phosphorus-containing gas is at least one selected from the group consisting of PF3 gas, PF5 gas, POF3 gas, HPF6 gas, PCl3 gas, PCl5 gas, POCl3 gas, PBr3 gas, PBr5 gas, POBr3 gas, PI3 gas, P4O 10 gas, P4O8 gas, P4O6 gas, PH3 gas, Ca3P2 gas, H3PO4 gas, and Na3PO4 gas.

[0034] In one exemplary embodiment, a step of preparing a substrate having a silicon-containing film on a substrate support in a chamber, a step of generating plasma in the chamber, and HF species and C contained in the plasma x H y F z (x is an integer of 2 or more, and y and z are integers of 1 or more.) A step of etching the silicon-containing film using the species, wherein the plasma contains active species of phosphorus and the amount of HF species is the largest.

[0035] In one exemplary embodiment, a substrate processing apparatus is provided. The substrate processing apparatus includes a chamber, a substrate support provided in the chamber, a plasma generation unit that supplies power for generating plasma in the chamber, and a control unit. The control unit controls to introduce into the chamber a processing gas containing at least one gas selected from the group consisting of C4H2F6 gas, C4H2F8 gas, C3H2F4 gas, and C3H2F6 gas, HF gas, and a phosphorus halide gas to etch the silicon-containing film of the substrate supported on the substrate support, and executes control to generate plasma by the power supplied from the plasma generation unit.

[0036] Hereinafter, with reference to the drawings, each embodiment of the present disclosure will be described in detail. In each drawing, the same or similar elements are denoted by the same reference numerals, and duplicate descriptions are omitted. Unless otherwise specified, the positional relationships such as up, down, left, and right are described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent the actual ratios, and the actual ratios are not limited to the illustrated ratios.

[0037] <Configuration of Substrate Processing Apparatus 1> FIG. 1 is a diagram schematically showing a substrate processing apparatus 1 according to one exemplary embodiment. A substrate processing method according to one exemplary embodiment (hereinafter referred to as "the present processing method") may be executed using the substrate processing apparatus 1.

[0038] The substrate processing apparatus 1 shown in FIG. 1 includes a chamber 10. The chamber 10 provides an internal space 10s therein. The chamber 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The chamber body 12 is formed of, for example, aluminum. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The corrosion-resistant film can be formed of a ceramic such as aluminum oxide or yttrium oxide.

[0039] A passage 12p is formed in the side wall of the chamber body 12. The substrate W is transported between the internal space 10s and the outside of the chamber 10 through the passage 12p. The passage 12p is opened and closed by a gate valve 12g. The gate valve 12g is provided along the side wall of the chamber body 12.

[0040] A support portion 13 is provided on the bottom of the chamber body 12. The support portion 13 is formed of an insulating material. The support portion 13 has a substantially 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.

[0041] The substrate support 14 has a lower electrode 18 and an electrostatic chuck 20. The substrate support 14 may further have an electrode plate 16. The electrode plate 16 is formed of a conductor such as aluminum and has a substantially disk shape. The lower electrode 18 is provided on the electrode plate 16. The lower electrode 18 is formed of a conductor such as aluminum and has a substantially disk shape. The lower electrode 18 is electrically connected to the electrode plate 16.

[0042] The electrostatic chuck 20 is provided on the lower electrode 18. The substrate W is placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a main body and an electrode. The main body of the electrostatic chuck 20 has a substantially disk shape and is formed of a dielectric. The electrode of the electrostatic chuck 20 is a film-like electrode and is provided inside the main body of the electrostatic chuck 20. The electrode of the electrostatic chuck 20 is connected to a DC power supply 20p via a switch 20s. When a voltage from the DC power supply 20p is applied to the electrode of the electrostatic chuck 20, an electrostatic attraction force is generated between the electrostatic chuck 20 and the substrate W. The substrate W is attracted to the electrostatic chuck 20 by the electrostatic attraction force and is held by the electrostatic chuck 20.

[0043] An edge ring 25 is disposed on the substrate support 14. The edge ring 25 is a ring-shaped member. The edge ring 25 can be formed of silicon, silicon carbide, quartz, or the like. The substrate W is disposed on the electrostatic chuck 20 and within a region surrounded by the edge ring 25.

[0044] 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 chiller unit provided outside the chamber 10 via a pipe 22a. The heat exchange medium supplied to the flow path 18f is returned to the chiller unit via a pipe 22b. In the substrate 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.

[0045] The substrate processing apparatus 1 is provided with a gas supply line 24. The gas supply line 24 supplies a heat transfer gas (for example, 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.

[0046] The substrate processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 14. The upper electrode 30 is supported on the upper part of the chamber body 12 via a member 32. The member 32 is formed of an insulating material. The upper electrode 30 and the member 32 close the upper opening of the chamber body 12.

[0047] 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 on the side of the internal space 10s and defines the internal space 10s. The top plate 34 may be formed of a low-resistance conductor or semiconductor that generates less Joule heat. The top plate 34 has a plurality of gas discharge holes 34a penetrating the top plate 34 in its plate thickness direction.

[0048] The support 36 detachably supports the top plate 34. The support 36 is formed of a conductive material such as aluminum. A gas diffusion chamber 36a is provided inside the support 36. The support 36 has a plurality of gas holes 36b extending downward from the gas diffusion chamber 36a. The plurality of gas holes 36b communicate with the plurality of gas discharge holes 34a respectively. A gas inlet 36c is formed in the support 36. The gas inlet 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet 36c.

[0049] A gas source group 40 is connected to a gas supply pipe 38 via a flow rate controller group 41 and a valve group 42. The flow rate controller group 41 and the valve group 42 constitute a gas supply unit. The gas supply unit may further include the gas source group 40. The gas source group 40 includes a plurality of gas sources. The plurality of gas sources include sources of process gases used in the present processing method. The flow rate controller group 41 includes a plurality of flow rate controllers. Each of the plurality of flow rate controllers in the flow rate controller group 41 is a mass flow controller or a pressure-controlled flow rate controller. The valve group 42 includes a plurality of on-off valves. Each of the plurality of gas sources in the gas source group 40 is connected to the gas supply pipe 38 via a corresponding flow rate controller in the flow rate controller group 41 and a corresponding on-off valve in the valve group 42.

[0050] In the substrate processing apparatus 1, a shield 46 is detachably provided along the inner wall surface of the chamber body 12 and the outer periphery of the support portion 13. The shield 46 prevents reaction by-products from adhering to the chamber body 12. The shield 46 is configured, 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 a ceramic such as yttrium oxide.

[0051] A baffle plate 48 is provided between the support portion 13 and the side wall of the chamber body 12. The baffle plate 48 is configured, for example, by forming a corrosion-resistant film (such as a film of yttrium oxide) on the surface of a member formed of aluminum. A plurality of through holes are formed in the baffle plate 48. An exhaust port 12e is provided below the baffle plate 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 includes a vacuum pump such as a pressure regulating valve and a turbo molecular pump.

[0052] The substrate processing apparatus 1 includes a high-frequency power supply 62 and a bias power supply 64. The high-frequency power supply 62 is a power supply that generates high-frequency power HF. The high-frequency power HF has a first frequency suitable for plasma generation. The first frequency is, for example, a frequency within the range of 27 MHz to 100 MHz. The high-frequency power supply 62 is connected to the lower electrode 18 via a matching unit 66 and an electrode plate 16. The matching unit 66 has a circuit for matching the impedance on the load side (lower electrode 18 side) of the high-frequency power supply 62 to the output impedance of the high-frequency power supply 62. Note that the high-frequency power supply 62 may be connected to the upper electrode 30 via the matching unit 66. The high-frequency power supply 62 constitutes an example of a plasma generation unit.

[0053] The bias power supply 64 is a power supply that generates 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 within the range of 400 kHz to 13.56 MHz. When the electrical bias is used together with the high-frequency power HF, it is applied to the substrate support 14 to draw ions into the substrate W. In one example, the electrical bias is applied to the lower electrode 18. 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. Note that the electrical bias may be applied to a bias electrode provided in the electrostatic chuck 20.

[0054] In one embodiment, the electrical bias may be high-frequency power LF having a second frequency. When the high-frequency power LF is used together with the high-frequency power HF, it is used as high-frequency bias power for drawing ions into the substrate W. The bias power supply 64 configured to generate the high-frequency power LF is connected to the lower electrode 18 via a matching unit 68 and an electrode plate 16. The matching unit 68 has a circuit for matching the impedance on the load side (lower electrode 18 side) of the bias power supply 64 to the output impedance of the bias power supply 64.

[0055] Note that plasma may be generated using only high-frequency power LF without using high-frequency power HF, that is, using only a single high-frequency power. In this case, the frequency of the high-frequency power LF may be a frequency greater than 13.56 MHz, for example, 40 MHz. Also, in this case, the substrate processing apparatus 1 may not include the high-frequency power supply 62 and the matcher 66. In this case, the bias power supply 64 constitutes an example of a plasma generation unit.

[0056] In another embodiment, the electrical bias may be a pulsed voltage (pulse voltage). In this case, the bias power supply may be a DC power supply. The bias power supply may be configured such that the power supply itself supplies a pulse voltage, or may be configured to include a device that pulses the voltage downstream of the bias power supply. In one example, the pulse voltage is applied to the lower electrode 18 so that a negative potential is generated on the substrate W. The pulse voltage may be a rectangular wave, a triangular wave, an impulse, or may have other waveforms.

[0057] The period of the pulse voltage is defined by a second frequency. The period of the pulse voltage includes two periods. The pulse voltage in one of the two periods is a voltage of negative polarity. The level (i.e., absolute value) of the voltage in one of the two periods is higher than the level (i.e., absolute value) of the voltage in the other of the two periods. The voltage in the other period may be either negative or positive polarity. The level of the negative-polarity voltage in the other period may be greater than zero or may be zero. In this embodiment, the bias power supply 64 is connected to the lower electrode 18 via a low-pass filter and the electrode plate 16. Note that the bias power supply 64 may be connected to a bias electrode provided in the electrostatic chuck 20 instead of the lower electrode 18.

[0058] In one embodiment, the bias power supply 64 may apply a continuous wave of electrical bias to the lower electrode 18. That is, the bias power supply 64 may continuously apply an electrical bias to the lower electrode 18.

[0059] In another embodiment, the bias power supply 64 may apply a pulsed wave of an electrical bias to the lower electrode 18. The pulsed wave of the electrical bias may be periodically applied to the lower electrode 18. The period of the pulsed wave of the electrical bias is defined by a third frequency. The third frequency is lower than the second frequency. The third frequency is, for example, 1 Hz or higher and 200 kHz or lower. In another example, the third frequency may be 5 Hz or higher and 100 kHz or lower.

[0060] The period of the pulsed wave of the electrical bias includes two periods, namely an H period and an L period. The level of the electrical bias in the H period (i.e., the level of the pulse of the electrical bias) is higher than the level of the electrical bias in the L period. That is, by increasing and decreasing the level of the electrical bias, the pulsed wave of the electrical bias may be applied to the lower electrode 18. The level of the electrical bias in the L period may be greater than zero. Alternatively, the level of the electrical bias in the L period may be zero. That is, the pulsed wave of the electrical bias may be applied to the lower electrode 18 by alternately switching the supply and the stop of the electrical bias to the lower electrode 18. Here, when the electrical bias is the high-frequency power LF, the level of the electrical bias is the power level of the high-frequency power LF. When the electrical bias is the high-frequency power LF, the level of the high-frequency power LF in the pulse of the electrical bias may be 2 kW or higher. When the electrical bias is a pulsed wave of a negative-polarity DC voltage, the level of the electrical bias is the effective value of the absolute value of the negative-polarity DC voltage. The duty ratio of the pulsed wave of the electrical bias, that is, the ratio occupied by the H period in the period of the pulsed wave of the electrical bias, is, for example, 1% or higher and 80% or lower. In another example, the duty ratio of the pulsed wave of the electrical bias may be 5% or higher and 50% or lower. Alternatively, the duty ratio of the pulsed wave of the electrical bias may be 50% or higher and 99% or lower. Note that, among the periods during which the electrical bias is supplied, the L period corresponds to the first period described above, and the H period corresponds to the second period described above. Also, the level of the electrical bias in the L period corresponds to 0 or the first level described above, and the level of the electrical bias in the H period corresponds to the second level described above.

[0061] In one embodiment, the high-frequency power supply 62 may supply a continuous wave of high-frequency power HF. That is, the high-frequency power supply 62 may continuously supply the high-frequency power HF.

[0062] In another embodiment, the high-frequency power supply 62 may supply a pulse wave of high-frequency power HF. The pulse wave of high-frequency power HF may be supplied periodically. The period of the pulse wave of high-frequency power HF is defined by a fourth frequency. The fourth frequency is lower than the second frequency. In one embodiment, the fourth frequency is the same as the third frequency. The period of the pulse wave of high-frequency power HF includes two periods, namely an H period and an L period. The power level of high-frequency power HF in the H period is higher than the power level of high-frequency power HF in the L period of the two periods. The power level of high-frequency power HF in the L period may be greater than zero or may be zero. Note that among the periods during which the high-frequency power HF is supplied, the L period corresponds to the above-described third period, and the H period corresponds to the above-described fourth period. Also, the level of high-frequency power HF in the L period corresponds to the above-described 0 or third level, and the level of the electrical bias in the H period corresponds to the above-described fourth level.

[0063] Note that the period of the pulse wave of high-frequency power HF may be synchronized with the period of the pulse wave of the electrical bias. The H period in the period of the pulse wave of high-frequency power HF may be synchronized with the H period in the period of the pulse wave of the electrical bias. Alternatively, the H period in the period of the pulse wave of high-frequency power HF may not be synchronized with the H period in the period of the pulse wave of the electrical bias. The time length of the H period in the period of the pulse wave of high-frequency power HF may be the same as or different from the time length of the H period in the period of the pulse wave of the electrical bias. Part or all of the H period in the period of the pulse wave of high-frequency power HF may overlap with the H period in the period of the pulse wave of the electrical bias.

[0064] FIG. 2 is a timing chart showing an example of high-frequency power HF and an electrical bias. FIG. 2 is an example in which both high-frequency power HF and the electrical bias use pulse waves. In FIG. 2, the horizontal axis represents time. In FIG. 2, the vertical axis represents the power levels of the high-frequency power HF and the electrical bias. "L1" of the high-frequency power HF indicates that the high-frequency power HF is not supplied or is lower than the power level indicated by "H1". "L2" of the electrical bias indicates that the electrical bias is not supplied or is lower than the power level indicated by "H2". When the electrical bias is a pulse wave of a negative DC voltage, the level of the electrical bias is the effective value of the absolute value of the negative DC voltage. Note that the magnitudes of the power levels of the high-frequency power HF and the electrical bias in FIG. 2 do not indicate the relative relationship between the two and may be arbitrarily set. FIG. 2 is an example in which the period of the pulse wave of the high-frequency power HF is synchronized with the period of the pulse wave of the electrical bias, and the time lengths of the H period and the L period of the pulse wave of the high-frequency power HF are the same as the time lengths of the H period and the L period of the pulse wave of the electrical bias.

[0065] Returning to FIG. 1, the description will be continued. The substrate processing apparatus 1 further includes a power source 70. The power source 70 is connected to the upper electrode 30. In one example, the power source 70 may be configured to supply a DC voltage or low-frequency power to the upper electrode 30 during plasma processing. For example, the power source 70 may supply a negative-polarity DC voltage to the upper electrode 30, or may supply low-frequency power periodically. The DC voltage or low-frequency power may be supplied as a pulse wave or as a continuous wave. In this embodiment, positive ions present in the plasma processing space 10s are drawn into and collide with the upper electrode 30. Thereby, secondary electrons are emitted from the upper electrode 30. The emitted secondary electrons modify the mask film MK and improve the etching resistance of the mask film MK. In addition, the secondary electrons contribute to an increase in plasma density. Further, due to the irradiation of the secondary electrons, the charged state of the substrate W is neutralized, so that the straightness of ions into the recess formed by etching is enhanced. Furthermore, when the upper electrode 30 is made of a silicon-containing material, silicon is emitted together with secondary electrons due to the collision of positive ions. The emitted silicon combines with oxygen in the plasma and deposits on the mask as a silicon oxide compound, functioning as a protective film. As described above, by supplying a DC voltage or low-frequency power to the upper electrode 30, not only the selectivity is improved, but also effects such as suppression of shape irregularities in the recess formed by etching and improvement of the etching rate can be obtained.

[0066] When plasma processing is performed in the substrate processing apparatus 1, gas is supplied from the gas supply unit to the internal space 10s. Further, by supplying high-frequency power HF and / or an electrical bias, a high-frequency electric field is generated between the upper electrode 30 and the lower electrode 18. The generated high-frequency electric field generates plasma from the gas in the internal space 10s.

[0067] The substrate processing apparatus 1 may further include a control unit 80. The control unit 80 can be a computer including a processor, a storage unit such as a memory, an input device, a display device, an input / output interface for signals, etc. The control unit 80 controls each part of the substrate processing apparatus 1. In the control unit 80, an operator can perform input operations of commands and the like for managing the substrate processing apparatus 1 by using the input device. Also, in the control unit 80, the operating status of the substrate processing apparatus 1 can be visualized and displayed by the display device. Furthermore, a control program and recipe data are stored in the storage unit. The control program is executed by the processor to execute various processes in the substrate processing apparatus 1. The processor executes the control program and controls each part of the substrate processing apparatus 1 according to the recipe data. In one exemplary embodiment, part or all of the control unit 80 may be provided as part of the configuration of a device external to the substrate processing apparatus 1.

[0068] <Configuration of the substrate processing system PS> FIG. 3 is a diagram schematically showing a substrate processing system PS according to one exemplary embodiment. This processing method may be executed using the substrate processing system PS.

[0069] The substrate processing system PS includes substrate processing chambers PM1 to PM6 (hereinafter also collectively referred to as "substrate processing modules PM"), a transfer module TM, load lock modules LLM1 and LLM2 (hereinafter also collectively referred to as "load lock modules LLM"), a loader module LM, and load ports LP1 to LP3 (hereinafter also collectively referred to as "load ports LP"). The control unit CT controls each component of the substrate processing system PS to execute a predetermined process on the substrate W.

[0070] The substrate processing module PM performs processes such as etching, trimming, film formation, annealing, doping, lithography, cleaning, and ashing on the substrate W inside it. A part of the substrate processing module PM may be a measurement module, and may measure the film thickness of a film formed on the substrate W, the dimensions of a pattern formed on the substrate W, and the like. The substrate processing apparatus 1 shown in FIG. 1 is an example of the substrate processing module PM.

[0071] The transfer module TM has a transfer device for transferring the substrate W, and transfers the substrate W between the substrate processing modules PM or between the substrate processing module PM and the load lock module LLM. The substrate processing module PM and the load lock module LLM are arranged adjacent to the transfer module TM. The transfer module TM, the substrate processing module PM, and the load lock module LLM are spatially isolated or connected by an openable and closable gate valve.

[0072] The load lock modules LLM1 and LLM2 are provided between the transfer module TM and the loader module LM. The load lock module LLM can switch the internal pressure between atmospheric pressure and vacuum. The load lock module LLM transfers the substrate W from the loader module LM at atmospheric pressure to the transfer module TM at vacuum, and also transfers it from the transfer module TM at vacuum to the loader module LM at atmospheric pressure.

[0073] The loader module LM has a transfer device for transferring the substrate W, and transfers the substrate W between the load lock module LLM and the load board LP. Inside the load port LP, for example, a FOUP (Front Opening Unified Pod) capable of accommodating 25 substrates W or an empty FOUP can be placed. The loader module LM takes out the substrate W from the FOUP in the load port LP and transfers it to the load lock module LLM. Also, the loader module LM takes out the substrate W from the load lock module LLM and transfers it to the FOUP in the load board LP.

[0074] The control unit CT controls each component of the substrate processing system PS to execute a predetermined process on the substrate W. The control unit CT stores a recipe in which the procedure of the process, the conditions of the process, the transfer conditions, etc. are set, and controls each component of the substrate processing system PS so as to execute a predetermined process on the substrate W according to the recipe. The control unit CT may also serve as part or all of the functions of the control unit 80 of the substrate processing apparatus 1 shown in FIG. 1.

[0075] <An example of the substrate W> FIG. 4 is a diagram showing an example of the cross-sectional structure of the substrate W. The substrate W is an example of a substrate to which the present processing method can be applied. The substrate W has a silicon-containing film SF. The substrate W may have an underlying film UF and a mask film MK. As shown in FIG. 4, the substrate W may be formed by laminating the underlying film UF, the silicon-containing film SF, and the mask film MK in this order.

[0076] The underlying film UF may be, for example, a silicon wafer, an organic film formed on a silicon wafer, a dielectric film, a metal film, a semiconductor film, or the like. The underlying film UF may be composed of a plurality of films laminated.

[0077] The silicon-containing film SF may be a silicon oxide film, a silicon nitride film, a silicon oxynitride film (SiON film), or a Si-ARC film. The silicon-containing film SF may include a polycrystalline silicon film. The silicon-containing film SF may be composed of a plurality of films laminated. For example, the silicon-containing film SF may be formed by alternately laminating a silicon oxide film and a polycrystalline silicon film. In one example, the silicon-containing film SF is a laminated film in which a silicon oxide film and a silicon nitride film are alternately laminated.

[0078] The underlying film UF and / or the silicon-containing film SF may be formed by a CVD method, a spin coating method, or the like. The underlying film UF and / or the silicon-containing film SF may be a flat film, or may be a film having irregularities.

[0079] The mask film MK is formed on the silicon-containing film SF. The mask film MK defines at least one opening OP on the silicon-containing film SF. The opening OP is a space on the silicon-containing film SF and is surrounded by the side walls S1 of the mask film MK. That is, in FIG. 4, the silicon-containing film SF has a region covered by the mask film MK and a region exposed at the bottom of the opening OP.

[0080] The opening OP may have an arbitrary shape in a plan view of the substrate W (when the substrate W is viewed from the top to the bottom in FIG. 4). The shape may be, for example, a hole shape, a line shape, or a combination of a hole shape and a line shape. The mask film MK has a plurality of side walls S1, and the plurality of side walls S1 may define a plurality of openings OP. The plurality of openings OP may each have a line shape and may be arranged at regular intervals to form a line & space pattern. Also, the plurality of openings OP may each have a hole shape and may form an array pattern.

[0081] The mask film MK is, for example, an organic film or a metal-containing film. The organic film may be, for example, a spin-on carbon film (SOC), an amorphous carbon film, or a photoresist film. The metal-containing film may include, for example, tungsten, tungsten carbide, or titanium nitride. The mask film MK may be formed by a CVD method, a spin coating method, or the like. The opening OP may be formed by etching the mask film MK. The mask film MK may also be formed by lithography.

[0082] <An example of this processing method> FIG. 5 is a flowchart showing this processing method. This processing method includes a step of preparing a substrate (step ST1) and an etching step (step ST2). Hereinafter, a case will be described as an example in which the control unit 80 shown in FIG. 1 controls each part of the substrate processing apparatus 1 to execute this processing method on the substrate W shown in FIG. 4.

[0083] (Step ST1: Preparation of the substrate) In step ST1, the substrate W is prepared within the internal space 10s of the chamber 10. Within the internal space 10s, the substrate W is placed on the upper surface of the substrate support 14 and held by the electrostatic chuck 20. At least a part of the process of forming each component of the substrate W may be performed within the internal space 10s. Further, after all or part of each component of the substrate W is formed by a device or chamber outside the substrate processing apparatus 1, the substrate W may be carried into the internal space 10s and placed on the upper surface of the substrate support 14.

[0084] (Step ST2: Etching process) In step ST2, etching of the silicon-containing film SF on the substrate W is performed. Step ST2 includes a step of supplying a processing gas (step ST21) and a step of generating plasma (step ST22). The silicon-containing film SF is etched by the active species (ions, radicals) of the plasma generated from the processing gas.

[0085] In step ST21, the processing gas is supplied from the gas supply unit into the internal space 10s. The processing gas includes, as a reaction gas, a fluorine-containing gas, C x H y F z (a gas different from the aforementioned fluorine-containing gas, where x is an integer of 2 or more, and y and z are integers of 1 or more.) gas (hereinafter, this gas is also referred to as "C x H y F z gas"), and a phosphorus-containing gas. In the present embodiment, unless otherwise specified, the reaction gas does not include noble gases such as Ar.

[0086] C x H y F z gas is, for example, C2HF5 gas, C2H2F4 gas, C2H3F3 gas, C2H4F2 gas, C3HF7 gas, C3H2F2 gas, C3H2F4 gas, C3H2F6 gas, C3H3F5 gas, C4H2F6 gas, C4H5F5 gas, C4H2F8 gas, C5H2F6 gas, C5H2F 10At least one selected from the group consisting of a gas and a C5H3F7 gas may be used. In one example, C x H y F z As the gas, at least one selected from the group consisting of a C3H2F4 gas, a C3H2F6 gas, a C4H2F6 gas, and a C4H2F8 gas is used. In another example, C x H y F z As the gas, at least one selected from the group consisting of a C3H2F4 gas, a C3H2F6 gas, a C4H2F6 gas, a C4H2F8 gas, and a C5H2F6 gas is used. C x H y F z When using, for example, a C4H2F6 gas as the C

[0087] C x H y F z In the plasma generated from the processing gas containing the gas, C x H y F z Species dissociated from the gas are included. This C x H y F z Species contains C x H y F z Species containing two or more carbon atoms are rich in C x H y F z Radicals (for example, C2H2F radical, C2H2F2 radical, C3HF3 radical. Hereinafter referred to as "C x H y F z -based radicals"). C x H y F z -based radicals form a protective film on the surface of the mask film MK to protect the surface. The protective film can suppress the etching of the mask film MK during the etching of the silicon-containing film SF. Therefore, C x H y F zThe radical can improve the selectivity of the silicon-containing film SF with respect to the mask film MK (the value obtained by dividing the etching rate of the silicon-containing film SF by the etching rate of the mask MK) in the etching of the silicon-containing film SF.

[0088] Also, C x H y F z In the plasma generated from the processing gas containing the gas, there are many HF species dissociated from the C x H y F z gas and / or further dissociated from the C x H y F z species. The HF species include at least one of hydrogen fluoride gas, radicals, and ions. The HF species function as an etchant for the silicon-containing film SF. By including a large amount of HF species in the plasma, the etching rate of the silicon-containing film SF can be improved. C x H y F z The gas may have one or more CF3 groups. C x H y F z When the C

[0089] H x H y F z gas has a CF3 group, for example, when a CH group is singly bonded to the CF3 group, due to its molecular structure, it is easily dissociated into HF and can increase the HF species in the plasma.

[0090] C x Hy F z The flow rate of the gas may be 20% by volume or less with respect to the total flow rate of the reaction gas. C x H y F z The flow rate of the gas may be, for example, 15% by volume or less, 10% by volume or less, or 5% by volume or less with respect to the total flow rate of the reaction gas. C x H y F z When the flow rate of the gas is 20% by volume or less with respect to the total flow rate of the reaction gas, it is possible to suppress excessive deposition of carbon on the side walls of the mask film MK and the silicon-containing film SF during etching and blockage of the opening OP of the mask film MK.

[0091] The fluorine-containing gas may be a gas capable of generating hydrogen fluoride (HF) species in the chamber 10 during plasma processing. The HF species includes at least any one of hydrogen fluoride gas, radicals, and ions. In one example, the fluorine-containing gas may be HF gas or hydrofluorocarbon gas. Further, the fluorine-containing gas may be a mixed gas containing a hydrogen source and a fluorine source. The hydrogen source may be, for example, H2, NH3, H2O, H2O2, or hydrocarbon (CH4, C3H6, etc.). The fluorine source may be NF3, SF6, WF6, XeF2, fluorocarbon, or hydrofluorocarbon. Hereinafter, these fluorine-containing gases are also referred to as "HF-based gases". The plasma generated from the processing gas containing the HF-based gas contains a large amount of HF species (etchant). The flow rate of the HF-based gas is C x H y F z It may be more than the flow rate of the gas. The HF-based gas may be the main etchant gas. The HF-based gas may have the largest flow rate ratio in the total flow rate of the reaction gas. For example, it may be 70% by volume or more with respect to the total flow rate of the reaction gas. Further, the HF-based gas may be 96% by volume or less with respect to the total flow rate of the reaction gas.

[0092] The phosphorus-containing gas can protect the sidewalls of the silicon-containing film SF and promote the adsorption of the etchant at the bottom BT of the silicon-containing film SF during the etching of the silicon-containing film SF. The phosphorus-containing gas may be at least one selected from the group consisting of PF3 gas, PF5 gas, POF3 gas, HPF6 gas, PCl3 gas, PCl5 gas, POCl3 gas, PBr3 gas, PBr5 gas, POBr3 gas, PI3 gas, P4O 10 gas, P4O8 gas, P4O6 gas, PH3 gas, Ca3P2 gas, H3PO4 gas, and Na3PO4 gas. Among these gases, phosphorus-containing halogen gases such as PF3 gas, PF5 gas, and PCl3 gas may be used, or phosphorus fluoride gases such as PF3 gas and PF5 gas may be used.

[0093] The processing gas may further contain at least one selected from the group consisting of a halogen-containing gas, a carbon-containing gas, a nitrogen-containing gas, and an oxygen-containing gas as a reaction gas. In one example, the processing gas further contains an oxygen-containing gas as a reaction gas. In another example, the processing gas further contains an oxygen-containing gas, a halogen-containing gas, and / or a carbon-containing gas as a reaction gas.

[0094] The halogen-containing gas can adjust the shape of the mask film MK and the silicon-containing film SF in etching. The halogen-containing gas may be a gas containing a halogen element other than fluorine. The halogen-containing gas can adjust the shape of the mask film MK and the silicon-containing film SF in etching. The halogen-containing gas may be a chlorine-containing gas, a bromine-containing gas, and / or an iodine-containing gas. As the chlorine-containing gas, gases such as Cl2, SiCl2, SiCl4, CCl4, SiH2Cl2, Si2Cl6, CHCl3, SO2Cl2, BCl3, PCl3, PCl5, and POCl3 may be used. As the bromine-containing gas, gases such as Br2, HBr, CBr2F2, C2F5Br, PBr3, PBr5, POBr3, and BBr3 may be used. As the iodine-containing gas, gases such as HI, CF3I, C2F5I, C3F7I, IF5, IF7, I2, and PI3 may be used. In one example, at least one selected from the group consisting of Cl2 gas, Br2 gas, HBr gas, CF3I gas, IF7 gas, and C2F5Br is used as the halogen-containing gas. In another example, Cl2 gas and HBr gas are used as the halogen-containing gas.

[0095] The carbon-containing gas can deposit carbon on the surface of the mask film MK in etching and protect the surface. The carbon-containing gas is C a H b (where a and b are integers of 1 or more) gas, C c F d (where c and d are integers of 1 or more) gas, and CH e F f (where e and f are integers of 1 or more) gas, and may be at least one selected from the group consisting of. C a H b gas may be, for example, CH4 gas or C3H6 gas, etc. C c F d gas may be, for example, CF4 gas, C3F8 gas, C4F6 gas, or C4F8 gas, etc. CH e F f gas may be, for example, CH2F2 gas, CHF3 gas, or CH3F gas, etc.

[0096] The nitrogen-containing gas can suppress the blockage of the opening OP of the mask film MK in etching. The nitrogen-containing gas may be, for example, at least one gas selected from the group consisting of NF3 gas, N2 gas, and NH3 gas.

[0097] Similar to the nitrogen-containing gas, the oxygen-containing gas can suppress the blockage of the opening OP of the mask film MK in etching. The oxygen-containing gas may be, for example, at least one gas selected from the group consisting of O2, CO, CO2, H2O, and H2O2. In one example, the processing gas contains at least one gas selected from the group consisting of oxygen-containing gases other than H2O, that is, O2, CO, CO2, and H2O2. The oxygen-containing gas causes less damage to the mask film MK and can suppress the deterioration of the morphology.

[0098] FIG. 6 is a diagram showing an example of the shape of the mask film MK after etching. FIG. 6 is an example of the shape (plan view) of the mask film MK when a sample substrate having the same structure as the substrate W is etched in the substrate processing apparatus 1. In FIG. 6, "No." indicates the sample number of the etched sample substrate. "Processing gas" indicates the processing gas used for etching, and "A" indicates a processing gas containing HF gas, C4H2F6 gas, O2 gas, NF3 gas, HBr gas, and Cl2 gas (hereinafter referred to as "processing gas A"). Processing gas A contains 80% by volume or more of HF gas with respect to the total flow rate of the reaction gas and contains 4 to 5% by volume of O2 gas with respect to the total flow rate of the reaction gas. "B" of "processing gas" indicates the same processing gas as processing gas A (hereinafter referred to as "processing gas B") except that it does not contain NF3 gas and the flow rate of O2 gas is increased accordingly. Processing gas B contains 6 to 7% by volume of O2 gas with respect to the total flow rate of the reaction gas. "Yes" in "upper electrode application" indicates that a negative DC voltage was supplied to the upper electrode 30 of the substrate processing apparatus 1 during etching, and "no" indicates that a negative DC voltage was not supplied to the upper electrode 30. From the "mask shape" in FIG. 6, it can be seen that when using processing gas A containing NF3, whether "yes" or "no" in "upper electrode application", the circularity of the opening OP deteriorates and a step is formed on a part of the surface of the mask film MK (samples 1 and 3). On the other hand, when using processing gas B that does not contain NF3 gas and has an increased flow rate of O2 gas (samples 2 and 4), the circularity of the opening OP is high, and no step is formed on the surface of the mask film MK. It can be seen that the morphology of the mask film MK is improved compared to the case of using processing gas A (samples 1 and 3).

[0099] In addition, in a state where an oxygen-containing gas exists in addition to the phosphorus-containing gas, the adsorption of the etchant at the bottom BT of the silicon-containing film SF is further promoted, so that the etching rate of the silicon-containing film SF can be further improved.

[0100] In addition, the processing gas may contain a boron-containing gas such as BF3, BCl3, BBr3, or B2H6. Further, the processing gas may contain a sulfur-containing gas such as SF6 or COS.

[0101] The processing gas may contain an inert gas (noble gas such as Ar) in addition to the reaction gas described above.

[0102] The pressure of the processing gas supplied into the internal space within 10 s is adjusted by controlling the pressure regulating valve of the exhaust device 50 connected to the chamber main body 12. The pressure of the processing gas may be, for example, 5 mTorr (0.7 Pa) or more and 100 mTorr (13.3 Pa) or less, 10 mTorr (1.3 Pa) or more and 60 mTorr (8.0 Pa) or less, or 20 mTorr (2.7 Pa) or more and 40 mTorr (5.3 Pa) or less.

[0103] Next, in step ST22, high-frequency power and / or an electric bias is supplied from the plasma generation unit (high-frequency power supply 62 and / or bias power supply 64). Thereby, a high-frequency electric field is generated between the upper electrode 30 and the substrate support 14, and plasma is generated from the processing gas in the internal space 10 s. Active species such as ions and radicals in the generated plasma are attracted to the substrate W, and the substrate W is etched.

[0104] FIG. 7 is a diagram showing an example of the cross-sectional structure of the substrate W in step ST22. During the execution of step ST22, the mask film MK functions as a mask, and the portion of the silicon-containing film SF corresponding to the opening OP of the mask film MK is etched in the depth direction (the direction from top to bottom in FIG. 7), and a recess RC is formed. The recess RC is a space surrounded by the side wall S2 of the silicon-containing film SF. The aspect ratio of the recess RC formed in step ST22 may be 20 or more, and may be 30 or more, 40 or more, 50 or more, or 100 or more.

[0105] In this processing method, the processing gas is C x H y F zIt contains gas and HF-based gas, and a large number of HF species are generated in the plasma. Therefore, during the execution of step ST22, HF species (etchant) can be sufficiently supplied to the bottom BT of the recess RC formed in the silicon-containing film SF. Also, in this processing method, the processing gas contains a phosphorus-containing gas. Phosphorus active species (ions, radicals) in the plasma can promote the adsorption of HF species (etchant) at the bottom BT of the recess RC. Thereby, the etching rate of the silicon-containing film SF can be improved.

[0106] In step ST22, the temperature of the substrate support 14 may be controlled at a low temperature. The temperature of the substrate support 14 may be, for example, 20°C or lower, 0°C or lower, -10°C or lower, -20°C or lower, -30°C or lower, -40°C or lower, or -70°C or lower. The temperature of the substrate support 14 can be adjusted by a heat exchange medium supplied from a chiller unit. The adsorption coefficient of HF species increases more at low temperatures. Therefore, by controlling the temperature of the substrate support 14 at a low temperature to suppress the rise in the temperature of the substrate W, the adsorption of HF species (etchant) at the bottom BT of the recess RC is promoted. Thereby, the etching rate of the silicon-containing film SF can be improved.

[0107] In this processing method, the processing gas contains C x H y F z gas. C x H y F z gas generates a high density of C x H y F z -based radicals in the plasma. As shown in FIG. 7, C x H y F z radicals adsorb on the surface (upper surface T1 and side wall S1) of the mask film MK to form a protective film PF. The protective film PF suppresses the removal of the surface of the mask film MK by etching (the increase in the etching rate of the mask film MK) during the execution of step ST22. Thereby, the selectivity of the silicon-containing film SF with respect to the mask film MK is improved.

[0108] In this processing method, the processing gas contains a phosphorus-containing gas. In the plasma, phosphorus active species are generated from the phosphorus-containing gas. The phosphorus active species can combine with the elements contained in the mask film MK to form part of the protective film PF. For example, when the mask film MK contains carbon, the phosphorus active species can combine with the carbon on the surface of the mask MK to form part of the protective film PF. The binding energy between phosphorus and carbon is greater than the binding energy between carbons, and this protective film PF suppresses the removal of the surface of the mask film MK by etching (increase in the etching rate of the mask film MK) during the execution of step ST22. That is, the phosphorus-containing gas contained in the processing gas can contribute to an improvement in the selectivity ratio of the silicon-containing film SF.

[0109] As shown in FIG. 7, C x H y F z The protective film PF formed by radicals can also be formed on the sidewall S2 of the silicon-containing film SF. This protective film PF can suppress the lateral etching (left-right direction in FIG. 7) of the sidewall S2 of the silicon-containing film SF during the execution of step ST22. Thereby, the shape and / or dimensions of the recess RC formed in the silicon-containing film SF can be appropriately maintained. For example, widening of a part of the width of the recess RC formed in the silicon-containing film SF (bowing) or the recess RC being etched laterally and not advancing linearly in the depth direction (direction from top to bottom in FIG. 7) (bending or twisting, etc.) can be suppressed. Note that the protective film PF can become thinner in the depth direction of the silicon-containing film SF.

[0110] The phosphorus active species in the plasma described above can combine with the elements contained in the silicon-containing film SF to form part of the protective film PF. For example, when the silicon-containing film SF is a film containing oxygen such as a silicon oxide film or a silicon oxynitride film, the phosphorus active species in the plasma can combine with the oxygen in the silicon-containing film SF to form part of the protective film PF. The bond between phosphorus and oxygen is chemically strong, and the protective film PF containing the bond between phosphorus and oxygen is difficult to be removed by low-energy ions that collide with the sidewall S2 of the silicon-containing film SF at a shallow angle. Therefore, the protective film PF can suppress the lateral etching of the sidewall S2 of the silicon-containing film SF during the execution of step ST22. That is, the phosphorus-containing gas contained in the processing gas can contribute to appropriately maintaining the shape and / or dimensions of the recess RC formed in the silicon-containing film SF (for example, suppressing bowing, etc.).

[0111] In step ST22, when plasma is generated in the internal space 10s, an electrical bias pulse wave may be periodically applied from the bias power supply 64 to the substrate support 14. By periodically applying the electrical bias pulse wave, etching and the formation of the protective film PF can proceed alternately.

[0112] Also, during the execution of step ST2, the flow rate of the C x H y F z gas supplied to the internal space 10s may be changed. For example, after performing the first etching with a reaction gas containing the C x H y F z gas at the first partial pressure, the second etching may be performed with a reaction gas containing the C x H y F z gas at the second partial pressure. Thereby, for example, when the silicon-containing film SF is a laminated film of different materials, by controlling the flow rate of the C x H y F z gas according to the material of the film to be etched, the laminated film can be appropriately etched.

[0113] Also, during the execution of step ST2, C supplied to the internal space 10s x H y F z The flow rate of the gas may be different between the central portion and the peripheral portion of the substrate W in a plan view of the substrate W. Thereby, even when the dimensions of the opening OP surrounded by the side wall S1 of the mask film MK are different between the central portion and the peripheral portion of the substrate W, C x H y F z By controlling the distribution of the flow rate of the gas, the variation in the dimensions can be corrected.

[0114] Also, during the execution of step ST2, the pressure inside the chamber 10 (internal space 10s) and the electrical bias supplied from the bias power supply 64 to the substrate support 14 may be changed. For example, step ST2 may include a first step of setting the inside of the chamber 10 to a first pressure, supplying a first electrical bias to the substrate support 14, and etching the silicon-containing film SF, and a second step of setting the inside of the chamber 10 to a second pressure, supplying a second electrical bias to the substrate support 14, and etching the silicon-containing film SF. Step ST2 may alternately repeat the first step and the second step. The first pressure may be different from the second pressure, and may be, for example, greater than the second pressure. The first electrical bias may be different from the second electrical bias, and for example, the absolute value of the first electrical bias may be greater than the absolute value of the second electrical bias. By appropriately adjusting the first pressure, the second pressure, the first electrical bias, and the second electrical bias, for example, the silicon-containing film SF may be anisotropically etched in the first step until or immediately before the recess RC reaches the underlying film UF, and isotropically etched in the second step so as to laterally expand the bottom of the recess RC.

[0115] Hereinafter, various experiments conducted to evaluate this processing method will be described. The present disclosure is not limited by the following experiments.

[0116] (Experiment 1) FIG. 8 is a diagram showing the measurement results of Experiment 1. In Experiment 1, the amount of HF species generated in various reaction gases was measured. In Experiment 1, either one of C4H2F6 gas, C4F8 gas, C4F6 gas, and CH2F2 gas and Ar gas were supplied as reaction gases into the internal space 10s of the substrate processing apparatus 1 to generate plasma for 10 minutes, and the HF intensity before and after plasma generation was measured with a quadrupole mass analyzer. The temperature of the substrate support 14 was set at -40°C. The vertical axis in FIG. 8 indicates the difference between the HF intensity before plasma generation and the HF intensity after plasma generation. The larger the value on the vertical axis, the greater the amount of HF species generated in the plasma.

[0117] As shown in FIG. 8, for the C4H2F6 gas according to an embodiment of the reaction gas of the present processing method, compared with the C4F8 gas and C4F6 gas that do not contain hydrogen element, and also compared with the CH2F2 gas that contains hydrogen element, the amount of HF species generated in the plasma was large.

[0118] (Experiment 2) FIGS. 9 and 10 are diagrams showing the measurement results of Experiment 2. FIG. 9 shows the experimental results of etching a silicon oxide film by generating plasma from a processing gas that is a mixed gas of hydrogen fluoride gas and argon gas using the plasma processing apparatus 1. FIG. 10 shows the experimental results of etching a silicon oxide film by generating plasma from a processing gas that is a mixed gas of hydrogen fluoride gas, argon gas, and PF3 gas using the plasma processing apparatus 1. In Experiment 2, while changing the temperature of the substrate support 14, the silicon oxide film was etched, and the amount of hydrogen fluoride (HF) and the amount of SiF3 in the gas phase during the etching of the silicon oxide film were measured using a quadrupole mass analyzer. The horizontal axis in FIGS. 9 and 10 represents the temperature T (°C) of the substrate support 14, and the vertical axis represents the amounts of hydrogen fluoride (HF) and SiF3 (intensity standardized based on helium).

[0119] As shown in FIG. 9, when the processing gas is a mixed gas of hydrogen fluoride gas and argon gas, and the temperature of the substrate support 14 is about -60°C or lower, the amount of hydrogen fluoride (HF), which is an etchant, decreases, and the amount of SiF3, which is a reaction product generated by etching the silicon oxide film, increases. That is, when the processing gas is a mixed gas of hydrogen fluoride gas and argon gas, the amount of the etchant used in etching the silicon oxide film increases when the temperature of the substrate support 14 is about -60°C or lower.

[0120] As shown in FIG. 10, when the processing gas is a mixed gas of hydrogen fluoride gas, argon gas, and PF3 gas, and the temperature of the substrate support 14 is about 20°C or lower, the amount of hydrogen fluoride (HF), which is an etchant, decreases, and the amount of SiF3, which is a reaction product generated by etching the silicon oxide film, increases. That is, when the processing gas further contains PF3 gas in addition to hydrogen fluoride gas and argon gas, the amount of the etchant used in etching the silicon oxide film increases when the temperature of the substrate support 14 is about 20°C or lower.

[0121] From Experiment 2, it was found that the lower the temperature of the substrate support 14, the more the etching of the silicon oxide film is promoted, and the selectivity of the silicon oxide film with respect to the mask film MK can be improved. Also, when the processing gas contains PF3 gas, that is, when phosphorus active species are present on the surface of the silicon oxide film during etching, it was found that even when the temperature of the substrate support 14 is about 20°C or lower, the adsorption of the etchant to the silicon oxide film is promoted, and the etching rate can be improved.

[0122] (Experiment 3) Figures 11 and 12 are diagrams showing the measurement results of Experiment 3. In Experiment 3, a sample substrate having the same structure as the substrate W was prepared on the substrate support 14. A processing gas was supplied into the internal space 10s of the substrate processing apparatus 1 to generate plasma, and the silicon-containing film SF of the sample substrate was etched. The temperature of the substrate support 14 was set to -40°C. As the processing gas, processing gas 1 containing C4H2F6 gas, HF gas, and PF3 gas, and processing gas 2 containing C4F8 gas and HF gas were used respectively. Processing gas 1 and processing gas 2 contained C4F8 gas and C4H2F6 gas at 5% by volume or less with respect to the total flow rate of the reaction gas. Processing gas 1 and processing gas 2 contained HF gas at 90% by volume or more with respect to the total flow rate of the reaction gas. Figure 11 shows the relationship between the aspect ratio (AR) of the concave portion RC and the selection ratio (Sel.) of the silicon-containing film SF with respect to the mask film MK. The selection ratio can be obtained by dividing the etching rate of the silicon-containing film SF by the etching rate of the mask film MK. Figure 12 shows the relationship between the aspect ratio (AR) of the concave portion RC and the maximum width (bowing CD: CD m [nm]) of the concave portion RC of the silicon-containing film SF.

[0123] As shown in Figures 11 and 12, when using processing gas 1 according to an embodiment of the processing gas of this processing method, even if the aspect ratio of the concave portion RC formed in the silicon-containing film SF becomes high, compared with the case of using processing gas 2, a high selection ratio is maintained and an increase in bowing CD is suppressed.

[0124] (Experiment 4) Figure 13 is a diagram for explaining an example of the method for evaluating the cross-sectional shape of the concave portion RC. In Figure 13, the central reference line CL is a line passing through the midpoint MP of the width of the concave portion RC on the lower surface of the mask film MK or the upper surface of the silicon-containing film SF. By measuring the deviation amount of the midpoint MP from the central reference line CL along the depth direction of the concave portion RC, the shape of the concave portion RC can be evaluated. For example, the bending and twisting of the concave portion RC formed in the silicon-containing film SF can be evaluated based on the deviation amount.

[0125] Figures 14 and 15 are diagrams showing the measurement results of Experiment 4. In Experiment 4, a sample substrate having the same structure as the substrate W was prepared on the substrate support 14. A processing gas was supplied into the internal space 10s of the substrate processing apparatus 1 to generate plasma, and the silicon-containing film SF of the sample substrate was etched. The temperature of the substrate support 14 was set to -40°C. As the processing gases, the same processing gases 1 and 2 as in Experiment 3 were used respectively. After the etching, for each of the processing gases 1 and 2, the shapes of the five recesses RC formed in the silicon-containing film SF were compared.

[0126] In FIG. 14, the vertical axis represents the depth D (μm) of the recess RC formed in the silicon-containing film SF. The depth 0 is the boundary with the mask film MK. The horizontal axis represents the average deviation amount S (nm). The average deviation amount S is obtained by measuring the deviation amount of the midpoint MP from the center reference line CL described in FIG. 13 along the depth direction for each of the five recesses RC and averaging these deviation amounts. As shown in FIG. 14, when the processing gas 1 according to an embodiment of the present processing method was used, the average deviation amount S was small throughout the depth direction. When the processing gas 2 was used, the average deviation amount S increased as the depth of the recess RC increased.

[0127] The deviation amount of each of the above-described concave portions RC can take either positive or negative values depending on the bending direction of the concave portion RC. Therefore, even if the absolute value of the deviation amount of each concave portion RC is large, if there is variation in the bending direction of each concave portion RC, the average deviation amount S can be small. Thus, as shown in FIG. 15, the average (variance) of the absolute values of the deviation amounts of each concave portion RC was also evaluated. In FIG. 15, the vertical axis represents the variance Sabs (nm) of the above five concave portions RC. The variance Sabs is the average of the absolute values of the respective deviation amounts of each concave portion RC. The horizontal axis represents the depth D (μm) of the concave portion RC formed in the silicon-containing film SF. A depth of 0 is the boundary with the mask film MK. As shown in FIG. 15, when using the processing gas 1, compared with the processing gas 2, even when the depth increased, the increase in the variance Sabs (nm) was suppressed. According to FIG. 15, in FIG. 14, when using the processing gas 1, the reason that the average deviation amount S was small over the entire depth direction is considered to be not because there were positive and negative variations in the bending direction of each concave portion RC, but because the deviation amount itself of each concave portion RC was small.

[0128] From Experiment 4, it was found that when using the processing gas 1 according to one embodiment of the present processing method, compared with the case of using the processing gas 2, the bending and twisting of the concave portion RC were suppressed, and the etching proceeded more in the vertical direction.

[0129] Further, the disclosed embodiment further includes the following aspects.

[0130] (Appendix 1) An etching gas composition containing at least one gas selected from the group consisting of C4H2F6 gas, C4H2F8 gas, C3H2F4 gas, and C3H2F6 gas, HF gas, and a phosphorus halide gas.

[0131] (Appendix 2) The etching gas composition according to Appendix 1, wherein the phosphorus halide gas contains at least one selected from the group consisting of PF3 gas, PF5 gas, POF3 gas, HPF6 gas, PCl3 gas, PCl5 gas, POCl3 gas, PBr3 gas, PBr5 gas, POBr3 gas, or PI3 gas.

[0132] (Appendix 3) The etching gas composition according to Appendix 1 or Appendix 2, further comprising at least one selected from the group consisting of a halogen-containing gas, a carbon-containing gas, an oxygen-containing gas, and a nitrogen-containing gas.

[0133] (Appendix 4) The etching gas composition according to Appendix 3, wherein the halogen-containing gas is at least one selected from the group consisting of a chlorine-containing gas, a bromine-containing gas, and an iodine-containing gas.

[0134] (Appendix 5) The etching gas composition according to Appendix 3, wherein the halogen-containing gas is at least one gas selected from the group consisting of Cl2, SiCl2, SiCl4, CCl4, SiH2Cl2, Si2Cl6, CHCl3, SO2Cl2, BCl3, PCl3, PCl5, POCl3, Br2, HBr, CBr2F2, C2F5Br, PBr3, PBr5, POBr3, BBr3, HI, CF3I, C2F5I, C3F7I, IF5, IF7, I2, and PI3.

[0135] (Appendix 6) The carbon-containing gas is C a H b (where a and b are integers of 1 or more) gas, C c F d (where c and d are integers of 1 or more) gas, and CH e F f (where e and f are integers of 1 or more) gas, and is at least one selected from the group consisting of the etching gas compositions according to any one of Appendices 3 to 5.

[0136] (Appendix 7) The etching gas composition according to any one of Appendices 3 to 6, wherein the nitrogen-containing gas is at least one selected from the group consisting of NF3 gas, N2 gas, and NH3 gas.

[0137] (Appendix 8) The etching gas composition according to any one of Appendices 1 to 6, further containing an oxygen-containing gas, wherein the oxygen-containing gas is at least one selected from the group consisting of O2 gas, CO gas, CO2 gas, H2O gas, and H2O2 gas.

[0138] (Appendix 9) The etching gas composition according to any one of Appendices 1 to 8, further containing at least one selected from the group consisting of a boron-containing gas and a sulfur-containing gas.

[0139] (Appendix 10) The etching gas composition according to any one of Appendices 1 to 9, further containing an inert gas.

[0140] This processing method can be variously modified without departing from the scope and spirit of the present disclosure. For example, this processing method may be executed using a substrate processing apparatus using an arbitrary plasma source such as an inductively coupled plasma or a microwave plasma, in addition to the capacitively coupled substrate processing apparatus 1.

Explanation of Reference Numerals

[0141] 1... Substrate processing apparatus, 10... Chamber, 10s... Internal space, 12... Chamber body, 14... Substrate supporter, 16... Electrode plate, 18... Lower electrode, 20... Electrostatic chuck, 30... Upper electrode, 50... Exhaust device, 62... High-frequency power source, 64... Bias power source, 80... Control unit, CT... Control unit, SF... Silicon-containing film, MK... Mask film, OP... Opening, PF... Protective film, RC... Recess, UF... Underlayer film, W... Substrate

Claims

1. A step of preparing a substrate having a silicon-containing film in a chamber, C 4 H 2 F 6 gas, C 4 H 2 F 8 gas, C 3 H 2 F 4 gas and C 3 H 2 F 6 introducing into the chamber a processing gas containing at least one gas selected from the group consisting of C, H, F gas, C, H, F gas, C, H, F gas and C, H, F gas, HF gas, and phosphorus halide gas to generate plasma, and etching the silicon-containing film of the substrate; A substrate processing method including the above.

2. The phosphorus halide gas is PF 3 gas, PF 5 gas, POF 3 gas, HPF 6 gas, PCl 3 gas, PCl 5 gas, POCl 3 gas, PBr 3 gas, PBr 5 gas, POBr 3 gas or PI 3 gas, and the substrate processing method according to claim 1 includes at least one selected from the group consisting of these gases.

3. The substrate processing method according to any one of Claim 1 or Claim 2, wherein the processing gas further includes at least one selected from the group consisting of a halogen-containing gas, a carbon-containing gas, an oxygen-containing gas, and a nitrogen-containing gas.

4. The substrate processing method according to Claim 3, wherein the halogen-containing gas is at least one selected from the group consisting of a chlorine-containing gas, a bromine-containing gas, and an iodine-containing gas.

5. The halogen-containing gas is Cl 2 , SiCl 2 , SiCl 4 , CCl 4 , SiH 2 Cl 2 , Si 2 Cl 6 , CHCl 3 , SO 2 Cl 2 , BCl 3 , PCl 3 , PCl 5 , POCl 3 , Br 2 , HBr, CBr 2 F 2 , C 2 F 5 Br, PBr 3 , PBr 5 , POBr 3 , BBr 3 , HI, CF 3 I, C 2 F 5 , C 3 F 7 I, IF 5 , IF 7 , I 2 and PI 3 The substrate processing method according to claim 3, which is at least one gas selected from the group consisting of

6. The carbon-containing gas is C a H b (where a and b are integers of 1 or more), a gas, C c F d (where c and d are integers of 1 or more), a gas, and CH e F f (where e and f are integers of 1 or more), and is at least one selected from the group consisting of gases, and the substrate processing method according to any one of claims 3 to 5.

7. The nitrogen-containing gas is NF 3 gas, N 2 gas, and NH 3 gas, and is at least one selected from the group consisting of these gases. The substrate processing method according to any one of claims 3 to 6

8. The processing gas further includes an oxygen-containing gas, and the oxygen-containing gas is O 2 gas, CO gas, CO 2 gas, H 2 O gas, and H 2 O 2 The substrate processing method according to any one of claims 1 to 6, which is at least one selected from the group consisting of gas.

9. The substrate processing method according to any one of Claims 1 to 8, wherein the processing gas further includes at least one selected from the group consisting of a boron-containing gas and a sulfur-containing gas.

10. The substrate processing method according to any one of Claims 1 to 9, wherein the processing gas further includes an inert gas.

11. The substrate processing method according to any one of Claims 1 to 10, wherein the silicon-containing film includes at least one selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polysilicon film.

12. The substrate processing method according to any one of Claims 1 to 11, wherein the substrate has a mask made of an organic film or a metal-containing film that defines at least one opening on the silicon-containing film.

13. The step of etching includes applying an electrical bias to a substrate support in the chamber in a first period and a second period alternating with the first period, The electrical bias in the first period is 0 or a first level, and the electrical bias in the second period is a second level greater than the first level. The substrate processing method according to any one of Claims 1 to 12.

14. The step of etching includes supplying high-frequency power for generating plasma to the substrate support or an upper electrode facing the substrate support in a third period and a fourth period alternating with the third period, The level of the high-frequency power in the third period is 0 or a third level, and the level of the high-frequency power in the fourth period is a fourth level greater than the third level. The substrate processing method according to Claim 13, wherein at least a part of the second period and the fourth period overlaps.

15. The substrate processing method according to any one of claims 13 or 14, wherein the electrical bias is a pulsed voltage.

16. The substrate processing method according to any one of claims 1 to 15, wherein the etching step includes supplying a direct current voltage or low-frequency power to an upper electrode facing a substrate support in the chamber.

17. The etching step includes a first step of setting the pressure in the chamber to a first pressure and supplying a first electrical bias to a substrate support in the chamber to etch the silicon-containing film; a second step of setting the pressure in the chamber to a second pressure and supplying a second electrical bias to the substrate support to etch the silicon-containing film; and the substrate processing method according to any one of claims 1 to 16, wherein the first pressure is different from the second pressure and / or the first electrical bias is different from the second electrical bias.

18. The substrate processing method according to claim 17, wherein the first pressure is greater than the second pressure.

19. The substrate processing method according to any one of claims 17 or 18, wherein the absolute value of the magnitude of the first electrical bias is greater than the absolute value of the magnitude of the second electrical bias.

20. The substrate processing method according to any one of claims 17 to 19, wherein the first step and the second step are alternately repeated.

21. A step of preparing a substrate having a silicon-containing film in a chamber; C x H y F z (where x is an integer of 2 or more, and y and z are integers of 1 or more.) A process gas containing a gas, a fluorine-containing gas, and a phosphorus-containing gas is introduced into the chamber to generate plasma, and a silicon-containing film on the substrate is etched; A substrate processing method including.

22. The substrate processing method according to claim 21, wherein the fluorine-containing gas is a gas capable of generating HF species in the chamber.

23. The above-mentioned C x H y F z gas is a substrate processing method according to any one of claims 21 or 22, having one or more CF 3 groups.

24. The above-mentioned C x H y F z gas is at least one selected from the group consisting of C 3 H 2 F 4 gas, C 3 H 2 F 6 gas, C 4 H 2 F 6 gas, C 4 H 2 F 8 gas and C 5 H 2 F 6 The substrate processing method according to any one of claims 21 to 23, comprising at least one selected from the group consisting of gas.

25. The phosphorus-containing gas is PF 3 gas, PF 5 gas, POF 3 gas, HPF 6 gas, PCl 3 gas, PCl 5 gas, POCl 3 gas, PBr 3 gas, PBr 5 gas, POBr 3 gas, PI 3 gas, P 4 O 10 gas, P 4 O 8 gas, P 4 O 6 gas, PH 3 gas, Ca 3 P 2 gas, H 3 PO 4 gas and Na 3 PO 4 The substrate processing method according to any one of claims 21 to 24, comprising at least one selected from the group consisting of gas.

26. A step of preparing a substrate having a silicon-containing film on a substrate support in a chamber; A step of generating plasma in the chamber; The step of etching the silicon-containing film using HF species and C species contained in the plasma, x H y F z where x is an integer of 2 or more, and y and z are integers of 1 or more). The substrate processing method, wherein the plasma contains active species of phosphorus and has the largest amount of the HF species.

27. A chamber, a substrate support provided in the chamber, a plasma generation unit for supplying power for generating plasma in the chamber, and a control unit. The control unit introduces into the chamber a processing gas containing at least one gas selected from the group consisting of C 4 H 2 F 6 gas, C 4 H 2 F 8 gas, C 3 H 2 F 4 gas, and C 3 H 2 F 6 gas, HF gas, and a phosphorus halide gas, and executes control to generate plasma by the power supplied from the plasma generation unit. A substrate processing apparatus.

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