Substrate processing method and substrate processing apparatus

Abstract

In one illustrative embodiment, a substrate processing method is provided. This substrate processing method includes: a step in which a substrate that has a dielectric film is prepared on a substrate support apparatus within a chamber; and a step in which plasma is generated from a reaction gas and the dielectric film is etched, said reaction gas including HF gas and at least one type of CxHyFz gas selected from the group consisting of C4H2F6 gas, C4H2F8 gas, C3H2F4 gas, and C3H2F6 gas, wherein during the step in which etching is performed, the temperature of the substrate support apparatus is set to 0°C or less, and the flow rate of the HF gas is greater than the flow rate of the CxHyFz gas.

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 describes 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 the selectivity of etching of a dielectric film with respect to mask etching.

Means for Solving the Problems

[0005] In one exemplary embodiment of the present disclosure, a step of preparing a substrate having a dielectric film on a substrate support in a chamber, and HF gas, 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 generating plasma from a reaction gas containing at least one C x H y F z gas selected from the group consisting of gas, and etching the dielectric film, and in the step of etching, the temperature of the substrate support is set to 0°C or lower, and the flow rate of the HF gas is the C x Hy F z A substrate processing method is provided that is greater than the flow rate of the gas.

Advantages of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique for improving the selectivity of etching of a dielectric film with respect to mask etching can be provided.

Brief Description of the Drawings

[0007]

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Modes 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 dielectric film on a substrate support in a chamber, and generating a plasma from a reaction gas containing at least one 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 selected from the group consisting of at least one C x H y F z gas to etch the dielectric film. In the etching step, the temperature of the substrate support is set to 0 °C or lower, and the flow rate of the HF gas is higher than the flow rate of the C x H y F z gas.

[0010] In one exemplary embodiment, the flow rate of the C x H y F z gas is 20% by volume or less with respect to the total flow rate of the reaction gas.

[0011] In one exemplary embodiment, the flow rate of the HF gas is 70% by volume or more with respect to the total flow rate of the reaction gas.

[0012] In one exemplary embodiment, the reaction gas further includes a halogen-containing gas.

[0013] 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.

[0014] In one exemplary embodiment, the halogen-containing gas is Cl 2 , SiCl2 , 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 , CBr, PBr 3 , PBr 5 , POBr 3 , BBr 3 , HI, CF 3 , I, C 2 , F 5 , I, C 3 , F 7 , I, IF 5 , IF 7 , I 2 and PI 3 and is at least one gas selected from the group consisting of.

[0015] In one exemplary embodiment, the reaction gas includes a phosphorus-containing gas.

[0016] In one exemplary embodiment, the reaction gas includes an oxygen-containing gas.

[0017] In one exemplary embodiment, the reaction 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 plasma is generated from a process gas including a reaction gas and an inert gas.

[0019] In one exemplary embodiment, the dielectric film is a silicon-containing film.

[0020] 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.

[0021] 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 dielectric film.

[0022] In one exemplary embodiment, the etching step includes applying an electrical bias to the substrate support, and the period during which the electrical bias is applied to the substrate support includes 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.

[0023] In one exemplary embodiment, the etching step includes supplying high-frequency power for generating plasma to the substrate support or an upper electrode facing the substrate support. The period during which the high-frequency power is supplied includes 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. At least a part of the second period and the fourth period overlap.

[0024] In one exemplary embodiment, the electrical bias is a pulsed voltage.

[0025] In one exemplary embodiment, the etching step includes supplying a DC voltage or low-frequency power to an upper electrode facing the substrate support.

[0026] In one exemplary embodiment, the etching process includes a first step of setting the pressure inside the chamber to a first pressure and supplying a first electrical bias to the substrate support to etch the dielectric film, and a second step of setting the pressure inside the chamber to a second pressure and supplying a second electrical bias to the substrate support to etch the dielectric film, wherein the first pressure is different from the second pressure and / or the first electrical bias is different from the second electrical bias.

[0027] In one exemplary embodiment, the first pressure is greater than the second pressure.

[0028] 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.

[0029] In one exemplary embodiment, the first step and the second step are repeated alternately.

[0030] 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 including a silicon oxide film on a substrate support inside a chamber, and a step of generating plasma from a reaction gas including a fluorine-containing gas and C x H y F z (a gas different from the fluorine-containing gas, where x is an integer of 2 or more, and y and z are integers of 1 or more.) to etch the silicon-containing film, and in the etching step, the temperature of the substrate support is set to 0 °C or lower, and C x H y F z The flow rate of the gas is 20% by volume or less with respect to the total flow rate of the reaction gas.

[0031] In one exemplary embodiment, the fluorine-containing gas is a gas capable of generating HF species in the chamber.

[0032] In one exemplary embodiment, C x H y F z The gas has one or more CF 3 groups.

[0033] In one exemplary embodiment, C x H y F z The gas is C 3 H 2 F 4 The gas, C 3 H 2 F 6 The gas, C 4 H 2 F 6 The gas, C 4 H 2 F 8 The gas and C 5 H 2 F 6 includes at least one selected from the group consisting of the gas.

[0034] In one exemplary embodiment, among the reaction gases, the flow rate of the fluorine-containing gas is the highest.

[0035] 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 including a silicon oxide film on a substrate support in a chamber, a step of generating plasma in the chamber, and a step of etching the silicon-containing film using HF species and C x H y F z (x is an integer of 2 or more, and y and z are integers of 1 or more.) species, and the amount of HF species in the plasma is the highest.

[0036] In one exemplary embodiment, a substrate processing apparatus is provided. The substrate processing apparatus includes a chamber, a substrate support provided in the chamber and configured to be temperature-adjustable, a plasma generation unit that supplies power for generating plasma in the chamber, and a control unit. The control unit uses HF gas and C 4 H 2 F 6 The gas, C 4 H 2 F 8 The gas, C3 H 2 F 4 gas and C 3 H 2 F 6 At least one C selected from the group consisting of gas x H y F z A control for introducing a reaction gas containing gas into the chamber to generate plasma is executed. In the control, the temperature of the substrate support is set to 0°C or lower, and the flow rate of the HF gas is C x H y F z higher than the flow rate of the gas.

[0037] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are denoted by the same reference numerals, and redundant 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 actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0038] <Configuration of the 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.

[0039] 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 ceramics such as aluminum oxide and yttrium oxide.

[0040] A passage 12p is formed in the side wall of the chamber body 12. The substrate W is conveyed 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.

[0041] 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.

[0042] 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 disc 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 disc shape. The lower electrode 18 is electrically connected to the electrode plate 16.

[0043] 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 body and an electrode. The body of the electrostatic chuck 20 has a substantially disc shape and is formed of a dielectric. The electrode of the electrostatic chuck 20 is a film-like electrode and is provided within the 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.

[0044] 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.

[0045] 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.

[0046] The substrate processing apparatus 1 is provided with a gas supply line 24. The gas supply line 24 supplies a heat transfer gas (e.g., He gas) from a heat transfer gas supply mechanism to a gap between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W.

[0047] 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 by 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.

[0048] 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 can be formed of a low-resistance conductor or semiconductor that generates little Joule heat. The top plate 34 has a plurality of gas discharge holes 34a penetrating the top plate 34 in its plate thickness direction.

[0049] The support 36 detachably supports the top plate 34. The support 36 is formed of a conductive material such as aluminum. Inside the support 36, a gas diffusion chamber 36a is provided. 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.

[0050] To the gas supply pipe 38, a gas source group 40 is connected 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 the sources of the process gases used in this 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 the corresponding flow rate controller in the flow rate controller group 41 and the corresponding on-off valve in the valve group 42.

[0051] 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.

[0052] 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 formed, for example, by forming a corrosion-resistant film (such as a yttrium oxide film) on the surface of a member made of aluminum. A plurality of through holes are formed in the baffle plate 48. An exhaust port 12e is provided below the baffle plate 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 includes a vacuum pump such as a pressure regulating valve and a turbo molecular pump.

[0053] The substrate processing apparatus 1 includes a high-frequency power source 62 and a bias power source 64. The high-frequency power source 62 is a power source 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 source 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 source 62 to the output impedance of the high-frequency power source 62. Note that the high-frequency power source 62 may be connected to the upper electrode 30 via the matching unit 66. The high-frequency power source 62 constitutes an example of a plasma generation unit.

[0054] The bias power source 64 is a power source that generates an electrical bias. The bias power source 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.

[0055] 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. A 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 with the output impedance of the bias power supply 64.

[0056] Note that plasma may be generated using only the high-frequency power LF, that is, using only a single high-frequency power, without using the high-frequency power HF. 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 matching unit 66. In this case, the bias power supply 64 constitutes an example of a plasma generation unit.

[0057] 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 for pulsing the voltage on the downstream side 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 in the substrate W. The pulse voltage may be a rectangular wave, a triangular wave, an impulse, or may have other waveforms.

[0058] 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 negative-polarity voltage. 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-polarity 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 an 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.

[0059] In one embodiment, the bias power supply 64 may apply a continuous wave of the electrical bias to the lower electrode 18. That is, the bias power supply 64 may continuously apply the electrical bias to the lower electrode 18.

[0060] In another embodiment, the bias power supply 64 may apply a pulse wave of the electrical bias to the lower electrode 18. The pulse wave of the electrical bias can be applied to the lower electrode 18 periodically. The period of the pulse 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 more and 200 kHz or less. In another example, the third frequency may be 5 Hz or more and 100 kHz or less.

[0061] The period of the pulse wave of the electric bias includes two periods, namely the H period and the L period. The level of the electric bias in the H period (i.e., the level of the pulse of the electric bias) is higher than the level of the electric bias in the L period. That is, by increasing or decreasing the level of the electric bias, the pulse wave of the electric bias may be applied to the lower electrode 18. The level of the electric bias in the L period may be greater than zero. Alternatively, the level of the electric bias in the L period may be zero. That is, the pulse wave of the electric bias may be applied to the lower electrode 18 by alternately switching the supply and the supply stop of the electric bias to the lower electrode 18. Here, when the electric bias is the high-frequency power LF, the level of the electric bias is the power level of the high-frequency power LF. When the electric bias is the high-frequency power LF, the level of the high-frequency power LF in the pulse of the electric bias may be 2 kW or more. When the electric bias is the pulse wave of the negative DC voltage, the level of the electric bias is the effective value of the absolute value of the negative DC voltage. The duty ratio of the pulse wave of the electric bias, that is, the ratio occupied by the H period in the period of the pulse wave of the electric bias is, for example, 1% or more and 80% or less. In another example, the duty ratio of the pulse wave of the electric bias may be 5% or more and 50% or less. Alternatively, the duty ratio of the pulse wave of the electric bias may be 50% or more and 99% or less. Note that among the periods during which the electric 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 electric bias in the L period corresponds to 0 or the first level described above, and the level of the electric bias in the H period corresponds to the second level described above.

[0062] In one embodiment, the high-frequency power supply 62 may supply a continuous wave of the high-frequency power HF. That is, the high-frequency power supply 62 may continuously supply the high-frequency power HF.

[0063] In another embodiment, the high-frequency power supply 62 may supply a pulsed wave of high-frequency power HF. The pulsed wave of high-frequency power HF may be supplied periodically. The period of the pulsed 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 pulsed 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 among 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 high-frequency power HF is supplied, the L period corresponds to the third period described above, and the H period corresponds to the fourth period described above. Also, the level of high-frequency power HF in the L period corresponds to 0 or the third level described above, and the level of the electrical bias in the H period corresponds to the fourth level described above.

[0064] Note that the period of the pulsed wave of high-frequency power HF may be synchronized with the period of the pulsed wave of the electrical bias. The H period in the period of the pulsed wave of high-frequency power HF may be synchronized with the H period in the period of the pulsed wave of the electrical bias. Alternatively, the H period in the period of the pulsed wave of high-frequency power HF may not be synchronized with the H period in the period of the pulsed wave of the electrical bias. The duration of the H period in the period of the pulsed wave of high-frequency power HF may be the same as or different from the duration of the H period in the period of the pulsed wave of the electrical bias. A part or all of the H period in the period of the pulsed wave of high-frequency power HF may overlap with the H period in the period of the pulsed wave of the electrical bias.

[0065] 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 pulse waves are used for both the high-frequency power HF and the electrical bias. 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-polarity DC voltage, the level of the electrical bias is the effective value of the absolute value of the negative-polarity 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.

[0066] 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 existing 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, since the charging state of the substrate W is neutralized by the irradiation of the secondary electrons, 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 to function 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 anomalies in the recess formed by etching and improvement of the etching rate can be obtained.

[0067] 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.

[0068] 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, a signal input / output interface, 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 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. Further, 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.

[0069] <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.

[0070] 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.

[0071] 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 the film formed on the substrate W, the dimensions of the 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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 process procedures, process conditions, 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 function as part or all of the control unit 80 of the substrate processing apparatus 1 shown in FIG. 1.

[0076] <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 dielectric film DF. The substrate W may have an underlayer film UF and a mask film MK. As shown in FIG. 4, the substrate W may be formed by laminating the underlayer film UF, the dielectric film DF, and the mask film MK in this order.

[0077] The underlayer film UF may be, for example, a silicon wafer, an organic film, a dielectric film, a metal film, a semiconductor film, etc. formed on a silicon wafer. The underlayer film UF may be composed of a plurality of films laminated.

[0078] The dielectric film DF may be a silicon-containing film. The silicon-containing film is, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film (SiON film), or a Si-ARC film. The dielectric film DF may include a polycrystalline silicon film. The dielectric film DF may be composed of a plurality of films laminated. For example, the dielectric film DF may be formed by alternately laminating a silicon oxide film and a polycrystalline silicon film. In one example, the dielectric film DF is a laminated film in which a silicon oxide film and a silicon nitride film are alternately laminated.

[0079] The underlayer film UF and / or the dielectric film DF may be formed by a CVD method, a spin coating method, etc. The underlayer film UF and / or the dielectric film DF may be a flat film, or may be a film having irregularities.

[0080] The mask film MK is formed on the dielectric film DF. The mask film MK defines at least one opening OP on the dielectric film DF. The opening OP is a space on the dielectric film DF and is surrounded by the sidewall S1 of the mask film MK. That is, in FIG. 4, the dielectric film DF has a region covered by the mask film MK and a region exposed at the bottom of the opening OP.

[0081] The opening OP may have an arbitrary shape in a plan view of the substrate W (when the substrate W is viewed from top to 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 sidewalls S1, and the plurality of sidewalls S1 may define a plurality of openings OP. The plurality of openings OP may each have a line shape and be arranged at regular intervals to form a line & space pattern. Also, the plurality of openings OP may each have a hole shape and form an array pattern.

[0082] 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 contain, 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.

[0083] In one example, the substrate W may have a stacked film in which a silicon oxide film and a silicon nitride film are stacked on the underlying film UF as the dielectric film DF. Further, in one example, the substrate W may have a polycrystalline silicon film, silicon boride, or tungsten carbide as the mask film MK on the silicon nitride film. Further, the mask film MK may be a multilayer resist containing a polycrystalline silicon film, silicon boride, or tungsten carbide. In one example, the multilayer resist has a mask containing a hard mask on the polycrystalline silicon film. The hard mask has, in one example, a silicon oxide film (TEOS film). The silicon nitride film contained in the stacked film may be etched using the hard mask as a mask, and the silicon oxide film contained in the stacked film may be etched using the polycrystalline silicon film as a mask.

[0084] <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.

[0085] (Step ST1: Preparation of substrate) In step ST1, the substrate W is prepared inside the internal space 10s of the chamber 10. Inside the internal space 10s, the substrate W is disposed 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 inside 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 disposed on the upper surface of the substrate support 14.

[0086] (Step ST2: Etching step) In step ST2, etching of the dielectric film DF 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 dielectric film DF is etched by active species (ions, radicals) of the plasma generated from the processing gas.

[0087] In step ST21, the processing gas is supplied from the gas supply unit into the internal space 10s. The processing gas includes a fluorine-containing gas and 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.) The reaction gas (hereinafter, this gas is also referred to as "C x H y F z gas") is included. In the present embodiment, unless otherwise specified, the reaction gas does not include noble gases such as Ar.

[0088] 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 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 including a hydrogen source and a fluorine source. The hydrogen source may be, for example, H 2 、NH 3 、H 2 O、H 2 O 2 or hydrocarbon (CH 4 、C 3 H 6 etc.). The fluorine source may be NF 3 、SF 6 、WF 6 、XeF 2 、fluorocarbon or hydrofluorocarbon. Hereinafter, these fluorine-containing gases are also referred to as "HF-based gases". The plasma generated from the processing gas including 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 Fz It may be more than the flow rate of the gas. The HF-based gas may be the main etchant gas. The flow rate ratio of the HF-based gas in the total flow rate of the reaction gas may be the largest, for example, 70% by volume or more with respect to the total flow rate of the reaction gas. Also, the HF-based gas may be 96% by volume or less with respect to the total flow rate of the reaction gas.

[0089] C x H y F z The gas is, for example, 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) gas can be used. 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) As the gas, specifically, C 2 HF 5 gas, C 2 H 2 F 4 gas, C 2 H 3 F 3 gas, C 2 H 4 F 2 gas, C 3 HF 7 gas, C 3 H 2 F 2 gas, C 3 H 2 F 4 gas, C 3 H 2 F 6 gas, C 3 H 3 F 5 gas, C 4 H 2 F 6 gas, C 4 H 5 F 5 gas, C 4 H 2 F 8 gas, C 5 H 2 F 6 gas, C 5 H 2 F 10 gas and C5 H 3 F 7 At least one selected from the group consisting of gases may be used. In one example, C x H y F z As the gas, C 3 H 2 F 4 gas, C 3 H 2 F 6 gas, C 4 H 2 F 6 gas and C 4 H 2 F 8 At least one selected from the group consisting of gases is used. In another example, C x H y F z As the gas, 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 At least one selected from the group consisting of gases is used. C x H y F z As the gas, for example, C 4 H 2 F 6 When using gas, C 4 H 2 F 6 may be linear or cyclic.

[0090] C x H y F z In the plasma generated from the processing gas containing C x H y F z species dissociated from the gas are included. This C x H y F z speciesx H y F z The species include C containing 2 or more carbon atoms x H y F z radicals (e.g., C 2 H 2 F radical, C 2 H 2 F 2 radical, C 3 HF 3 radical. Hereinafter referred to as "C x H y F z -based radical"). There are many of them. C x H y F z 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 dielectric film DF. Therefore, C x H y F z -based radicals can improve the selectivity of the dielectric film DF with respect to the mask film MK (the value obtained by dividing the etching rate of the dielectric film DF by the etching rate of the mask MK) during the etching of the dielectric film DF.

[0091] Also, the plasma generated from the processing gas containing C x H y F z gas contains a large amount of HF species dissociated from C x H y F z gas and / or further dissociated from C x H y F z -based radicals. The HF species include at least one of hydrogen fluoride gas, radicals, and ions. The HF species function as an etchant for the dielectric film DF. By including a large amount of HF species in the plasma, the etching rate of the dielectric film DF can be improved.

[0092] C x H y F z gas may have one or more CF 3 groups. C x Hy F z When the gas has a CF 3 group, for example, when a CH group is singly bonded to the CF 3 group, due to its molecular structure, it is likely to dissociate as HF and can increase the amount of HF species in the plasma.

[0093] Note that the processing gas may include, instead of part or all of the above-mentioned C x H y F z gas, C x F z (where x is an integer of 2 or more and z is an integer of 1 or more) gas. Specifically, C 2 F 2 , C 2 F 4 , C 3 F 8 , C 4 F 6 , C 4 F 8 and C 5 F 8 selected from the group consisting of at least one may be used. Thereby, the amount of hydrogen in the plasma can be suppressed, and for example, deterioration of the morphology due to excessive hydrogen and an increase in moisture in the chamber 10 can be suppressed. Here, the morphology means characteristics related to the shape of the mask, such as the surface state of the mask film MK and the roundness of the opening OP.

[0094] C x H y F z The flow rate of the C x H y F z gas is 20% by volume or less with respect to the total flow rate of the reaction gas. The flow rate of the C

[0095] The reaction gas may include a halogen-containing gas. The halogen-containing gas can adjust the shape of the mask film MK and the dielectric film DF 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, Cl 2 , SiCl2 , 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 and other gases may be used. As the bromine-containing gas, Br 2 , HBr, CBr 2 F 2 , C 2 F 5 Br, PBr 3 , PBr 5 , POBr 3 , BBr 3 and other gases may be used. As the iodine-containing gas, HI, CF 3 I, C 2 F 5 I, C 3 F 7 I, IF 5 , IF 7 , I 2 , PI 3 and other gases may be used. In one example, as the halogen-containing gas, Cl 2 gas, Br 2 gas, HBr gas, CF 3 I gas, IF 7 gas and C 2 F 5 Br, at least one selected from the group consisting thereof is used. In another example, as the halogen-containing gas, Cl 2 gas and HBr gas are used.

[0096] The reaction gas may contain a nitrogen-containing gas. The nitrogen-containing gas can suppress the blockage of the opening OP of the mask film MK during etching. The nitrogen-containing gas may be, for example, at least one gas selected from the group consisting of NF 3 gas, N 2 gas and NH 3 gas.

[0097] The reaction gas may include an oxygen-containing gas. Similar to the nitrogen-containing gas, the oxygen-containing gas can suppress the blockage of the mask film MK in etching. Examples of the oxygen-containing gas include, for example, O 2 , CO, CO 2 , H 2 O, and H 2 O 2 . At least one gas selected from the group consisting of may be used. In one example, the reaction gas is an oxygen-containing gas other than H 2 O, that is, O 2 , CO, CO 2 , and H 2 O 2 . 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 in etching, and "A" indicates a processing gas containing HF gas, C 4 H 2 F 6 gas, O 2 gas, NF 3 gas, HBr gas, and Cl 2 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 O 2 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 NF 3 gas and the flow rate of O 2 gas is increased accordingly. Processing gas B is O 2It contains 6 to 7 volume % of the gas with respect to the total flow rate of the reaction gas. "Presence" of "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 "absence" indicates that a negative DC voltage was not supplied to the upper electrode 30. From the "mask shape" in FIG. 6, whether in the case of "presence" or "absence" of "upper electrode application", NF 3 When using the processing gas A containing NF (Samples 1 and 3), it can be seen that the roundness of the opening OP deteriorated and a step occurred on the surface of the mask film MK. On the other hand, NF 3 Without the gas, when using the processing gas B with an increased flow rate of O gas (Samples 2 and 4), the roundness of the opening OP is high, and there is no step 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 the processing gas A (Samples 1 and 3). 2

[0099] The reaction gas may contain a phosphorus-containing gas. Examples of the phosphorus-containing gas include, for example, PF 3 PF 5 POF 3 HPF 6 PCl 3 PCl 5 POCl 3 PBr 3 PBr 5 POBr 3 PI 3 P 4 O 10 P 4 O 8 P 4 O 6 PH 3 Ca 3 P 2 H 3 PO 4 And at least one gas selected from the group consisting of Na 3 PO 4 3 5 3 PF 3 PF 5 Such phosphorus halide-containing gases as PCl etc. may be used. For example, PF 3 PF 5Phosphorus fluoride-containing gases such as may be used.

[0100] In addition, the processing gas may include BF 3 , BCl 3 , BBr 3 , B 2 H 6 and other boron-containing gases. Further, the processing gas may include sulfur-containing gases such as SF 6 and COS.

[0101] The processing gas may include 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 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 electrical 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 within 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] In step ST22, the temperature of the substrate support 14 is set to 0 °C or lower. The temperature of the substrate support 14 to be set may be, for example, 0 °C or lower, -10 °C or lower, -20 °C or lower, -30 °C or lower, -40 °C or lower, -60 °C or lower, -70 °C or lower. The temperature of the substrate support 14 can be adjusted by a heat exchange medium supplied from the chiller unit.

[0105] FIG. 7 is a diagram showing an example of the temperature dependence of etching. FIG. 7 shows the experimental results of generating plasma from a processing gas, which is a mixed gas of hydrogen fluoride gas and argon gas, using the plasma processing apparatus 1 and etching a silicon oxide film. In this experiment, while changing the temperature of the substrate support 14, the silicon oxide film was etched, and a quadrupole mass analyzer was used to measure the amount of hydrogen fluoride (HF) and SiF 3 in the gas phase during the etching of the silicon oxide film. The horizontal axis in FIG. 7 represents the temperature T (° C) of the substrate support 14, and the vertical axis represents the amounts of hydrogen fluoride (HF) and SiF 3 (intensity standardized based on helium).

[0106] As shown in FIG. 7, when the temperature of the substrate support 14 is about -60° C or lower, the amount of hydrogen fluoride (HF), which is the etchant, decreases, and the amount of SiF 3 , which is a reaction product generated by etching the silicon oxide film, increases. That is, in this experiment, when the temperature of the substrate support 14 was about -60° C or lower, the amount of the etchant used in the etching of the silicon oxide film increased.

[0107] Therefore, from this experiment, 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 thus the selectivity of the dielectric film DF with respect to the mask film MK can be improved. Note that the temperature at which the amount of the etchant increases varies depending on the flow rate ratio of the hydrogen fluoride gas in the reaction gas and processing conditions such as additive gases. For this reason, the temperature of the substrate support 14 may be set based on the relationship between the temperature of the substrate support 14, the amount of hydrogen fluoride, and the amount of SiF 3 by examining the relationship under specific conditions and based on the results.

[0108] FIG. 8 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 dielectric film DF corresponding to the opening OP of the mask film MK is etched in the depth direction (the direction from top to bottom in FIG. 8), and the concave portion 01 RC is formed. The concave portion RC is a space surrounded by the side wall S1 of the mask film MK and the side wall S2 of the dielectric film DF. The aspect ratio of the concave portion 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.

[0109] In this processing method, the reaction gas contains C x H y F z gas. C x H y F z gas generates C x H y F z -based radicals at a high density in the plasma. C x H y F z -based radicals adsorb on the surface (upper surface T1 and side wall S1) of the mask film MK and the side wall S2 of the dielectric film DF to form the protective film PF. Note that the protective film PF may become thinner in the depth direction (the direction from top to bottom in FIG. 8). The protective film PF suppresses the removal of the surface of the mask film MK by etching during the execution of step ST22 (that is, an increase in the etching rate of the mask film MK). Thereby, the selectivity of the dielectric film DF with respect to the mask film MK is improved.

[0110] The protective film PF can suppress the etching of the dielectric film DF in the lateral direction (the left-right direction in FIG. 8). C x H y F zWhen the flow rate of the gas is 20% by volume or less with respect to the total flow rate of the reaction gas, carbon deposition on the side wall S1 of the mask film MK and / or the dielectric film DF can be more suppressed, and blockage of the opening OP of the mask film MK can be more suppressed. When the reaction gas contains an oxygen-containing gas, carbon deposition on the side wall S1 of the mask film MK and / or the dielectric film DF can be more suppressed, and blockage of the opening OP of the mask film MK can be more suppressed. Due to at least one of the above factors, the shape and / or dimensions of the recess RC formed in the dielectric film DF can be appropriately maintained.

[0111] C x H y F z In the gas, a large amount of HF species are generated in the plasma. Therefore, during the execution of step ST22, HF-based species (etchant) can be sufficiently supplied to the bottom BT of the recess RC formed in the dielectric film DF. Also, during the execution of step ST22, the temperature of the substrate support 14 is controlled to a low temperature of 0°C or lower. By suppressing the rise in the temperature of the substrate W, adsorption of HF species (etchant) at the bottom BT of the recess RC can be promoted (the adsorption coefficient of HF species increases more at low temperatures). Due to at least one of the above factors, the etching rate of the dielectric film DF can be improved.

[0112] Note that in step ST22, when plasma is being 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.

[0113] Also, during the execution of step ST2, the C x H y F z gas flow rate may be changed. For example, after performing the first etching with a reaction gas containing C x H y F z gas at a first partial pressure, C x H y F zSecond etching may be performed using a reaction gas containing a gas. Thereby, for example, when the dielectric film DF is a laminated film of different materials, C is adjusted according to the material of the film to be etched. x H y F z By controlling the flow rate of the gas, the laminated film can be appropriately etched.

[0114] Also, during the execution of step ST2, the 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.

[0115] 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 pressure inside the chamber 10 to a first pressure, supplying a first electrical bias to the substrate support 14, and etching the dielectric film DF, and a second step of setting the pressure inside the chamber 10 to a second pressure, supplying a second electrical bias to the substrate support 14, and etching the dielectric film DF. Step ST2 may alternately repeat the first step and the second step. The first pressure may be different from the second pressure, and for example, may be 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, in the first step, the dielectric film DF may be anisotropically etched until the recess RC reaches the underlying film UF or immediately before reaching it, and in the second step, the bottom of the recess RC may be isotropically etched so as to expand laterally.

[0116] The following describes various experiments conducted to evaluate this processing method. This disclosure is not limited in any way by the following experiments.

[0117] (Experiment 1) FIG. 9 is a diagram showing the measurement results of Experiment 1. In Experiment 1, the generation amount of HF species in various reaction gases was measured. In Experiment 1, into the internal space 10s of the substrate processing apparatus 1, either one of C 4 H 2 F 6 gas, C 4 F 8 gas, C 4 F 6 gas and CH 2 F 2 gas and Ar gas were supplied 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. 9 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 generation amount of HF species in the plasma.

[0118] As shown in FIG. 9, the C 4 H 2 F 6 gas according to an embodiment of the reaction gas of this processing method, the C 4 F 8 gas and C 4 F 6 gas, not to mention the CH 2 F 2 gas containing hydrogen element, had a greater generation amount of HF species in the plasma.

[0119] (Experiment 2) Figures 10 and 11 are diagrams showing the measurement results of Experiment 2. In Experiment 2, the etching rate and selectivity in various processing gases were measured. In Experiment 2, a sample substrate having the same structure as the substrate W was prepared on the substrate support 14. The sample substrate had a silicon oxide film as the dielectric film DF and an organic film as the mask film MK on the silicon film. A processing gas was supplied into the internal space 10s of the substrate processing apparatus 1 to generate plasma, and the dielectric film DF of the sample substrate was etched. The temperature of the substrate support 14 was set at -40°C. As shown in Figures 10 and 11, in each case where the reaction gas in the processing gas contained either C 4 F 8 gas, CH 2 F 2 gas or C 4 H 2 F 6 gas, the etching rate (E / R [nm / min], Figure 10) of the dielectric film DF and the selectivity (Sel., Figure 11) of the dielectric film DF with respect to the mask film MK were measured. The flow rate of the C 4 F 8 gas was 5% by volume of the total flow rate of the reaction gas. The flow rate of the CH 2 F 2 gas was 15% by volume of the total flow rate of the reaction gas. The flow rate of the C 4 H 2 F 6 gas was 5% by volume of the total flow rate of the reaction gas. The reaction gas contained 70 - 90% by volume of HF gas with respect to the total flow rate of the reaction gas.

[0120] As shown in Figures 10 and 11, the processing gas containing C 4 H 2 F 6 gas according to one example of the reaction gas of this processing method had higher values for both the etching rate and the selectivity compared to the processing gas containing C 4 F 8 gas or CH 2 F 2 gas as the reaction gas.

[0121] (Experiment 3) Figures 12 and 13 are diagrams showing the measurement results of Experiment 3. In Experiment 3, the etching rate and the bowing CD in various processing gases were measured when the aspect ratio of the concave portion RC was changed. In Experiment 3, a sample substrate having the same structure as in Experiment 2 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 dielectric film DF of the sample substrate was etched. The temperature of the substrate support 14 was set at -40°C. Figures 12 and 13 show, for each case where the reaction gas in the processing gas contains C 4 F 8 gas or C 4 H 2 F 6 gas, the selectivity (Sel., Figure 12) of the dielectric film DF with respect to the mask film MK when the aspect ratio (AR) of the concave portion RC is changed, and the relationship with the maximum width (bowing CD: CD m [nm], Figure 13) of the concave portion RC of the dielectric film DF. The selectivity can be obtained by dividing the etching rate of the dielectric film DF by the etching rate of the mask film MK. C 4 F 8 gas or C 4 H 2 F 6 gas was 5% by volume of the total flow rate of the reaction gas. The reaction gas contained 90% by volume or more of HF gas with respect to the total flow rate of the reaction gas.

[0122] As shown in Figures 12 and 13, when a reaction gas containing C 4 H 2 F 6 gas according to an embodiment of the processing gas of the present processing method is used, even when the aspect ratio of the concave portion RC formed in the dielectric film DF becomes high, compared with the case where a reaction gas containing C 4 F 8 gas is used, a high selectivity is maintained and an increase in the bowing CD is suppressed.

[0123] (Experiment 4) FIG. 14 is a diagram showing the measurement results of Experiment 4. In Experiment 4, the change over time in the emission spectrum intensity of CO (CO intensity) generated when the chamber 10 of the substrate processing apparatus 1 is cleaned with oxygen gas was measured. In FIG. 14, CH1 is the chamber after etching a sample substrate having the same structure as in Experiment 2 using a processing gas containing 4% by volume of C 4 H 2 F 6 gas with respect to the total flow rate of the reaction gas. CH2 is the chamber after etching a sample substrate having the same structure as in Experiment 2 using a processing gas containing 16% by volume of C 2 F 2 gas with respect to the total flow rate of the reaction gas. The CO intensity is measured by the reaction of the cleaning gas (oxygen gas) with the carbon-containing deposits in the chamber 10, and can be used as an indication of the cleaning progress in the chamber.

[0124] As shown in FIG. 14, the CO intensity in CH1 reached a peak immediately after the start of cleaning, then decreased rapidly, and became 0 at 20 to 30 seconds after the start of cleaning. The CO intensity in CH2 had a lower peak value than CH1, and the rate of decrease was also gentle, and it did not become 0 even 200 seconds after the start of cleaning. That is, when using a processing gas containing C 4 H 2 F 6 gas according to an example of the reaction gas of the present processing method, the cleaning time of the chamber after etching could be shortened compared to the case of using a processing gas containing C 2 F 2 gas.

[0125] The disclosed embodiment further includes the following aspects.

[0126] (Appendix 1) HF gas, and C 4 H 2 F 6 gas, C 4 H 2 F 8 gas, C 3 H 2 F 4Gas and C 3 H 2 F 6 At least one C selected from the group consisting of gases x H y F z A reaction gas containing a gas, wherein the flow rate of the HF gas is higher than the flow rate of the C x H y F z Gas, an etching gas composition.

[0127] (Appendix 2) The C x H y F z The flow rate of the gas is 20% by volume or less based on the total flow rate of the reaction gas. The etching gas composition according to Appendix 1.

[0128] (Appendix 3) The flow rate of the HF gas is 70% by volume or more based on the total flow rate of the reaction gas. The etching gas composition according to Appendix 1 or 2.

[0129] (Appendix 4) The reaction gas further contains a halogen-containing gas. The etching gas composition according to any one of Appendices 1 to 3.

[0130] (Appendix 5) 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. The etching gas composition according to Appendix 4.

[0131] (Appendix 6) 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 , PCl5 , POCl 3 , Br 2 , HBr, CBr 2 , F 2 , C 2 , CF 5 , Br, PBr 3 , PBr 5 , POBr 3 , BBr 3 , HI, CF 3 , I, C 2 , F 5 , I, C 3 , F 7 , I, IF 5 , IF 7 , I 2 , and PI 3 , at least one selected from the group consisting of, the etching gas composition according to Supplementary Note 4.

[0132] (Supplementary Note 7) , The reaction gas contains a phosphorus-containing gas, the etching gas composition according to any one of Supplementary Notes 1 to 5.

[0133] (Supplementary Note 8) , The reaction gas further contains an oxygen-containing gas, the etching gas composition according to any one of Supplementary Notes 1 to 7.

[0134] (Supplementary Note 9) , The reaction gas further contains at least one selected from the group consisting of a boron-containing gas and a sulfur-containing gas, the etching gas composition according to any one of Supplementary Notes 1 to 8.

[0135] , 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.

Description of Symbols

[0136] 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 supply, 64... Bias power supply, 80... Control unit, CT... Control unit, DF... Dielectric film, MK... Mask film, OP... Opening, PF... Protective film, RC... Concave portion, UF... Underlayer film, W... Substrate

Claims

1. providing a substrate on a substrate support in a chamber, the substrate having a dielectric film and a mask defining at least one opening on the dielectric film; HF gas and 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 At least one C gas selected from the group consisting of x H y F z generating a plasma from a reactive gas containing a gas, and etching the dielectric film through the mask; In the etching step, the temperature of the substrate holder is set to 0° C. or less, and the flow rate of the HF gas is set to C x H y F z A method for processing a substrate, the method comprising:

2. Said C x H y F z 2. The substrate processing method according to claim 1, wherein a flow rate of the gas is 20% by volume or less with respect to a total flow rate of the reaction gas.

3. 3. The substrate processing method according to claim 1, wherein a flow rate of the HF gas is 70% by volume or more with respect to a total flow rate of the reaction gas.

4. 4. The substrate processing method according to claim 1, wherein the reactive gas further contains a halogen-containing gas.

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

6. The halogen-containing gas is Cl 2 , SiCl 2 , SiCl 4 , CCl 4 , SiH 2 C 2 , Si 2 C 6 , CHCl 3 , S.O. 2 C 2 , BCl 3 , PCl 3 , PCl 5 , POCl 3 , B 2 , HBr, CBr 2 F 2 , C 2 F 5 Br, PBr 3 , PBr 5 , POBr 3 , BBr 3 , H.I., C.F. 3 I.C. 2 F 5 I.C. 3 F 7 I, IF 5 , I.F. 7 , I 2 and P.I. 3 5. The method of claim 4, wherein the gas is at least one gas selected from the group consisting of:

7. 7. The substrate processing method according to claim 1, wherein the reactive gas includes a phosphorus-containing gas.

8. 8. The substrate processing method according to claim 1, wherein the reactive gas includes an oxygen-containing gas.

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

10. 10. The substrate processing method according to claim 1, wherein the plasma is generated from a process gas containing the reactive gas and an inert gas.

11. The substrate processing method according to claim 1 , wherein the dielectric film is a silicon-containing film.

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

13. 13. The substrate processing method according to claim 1, wherein the substrate has a mask made of an organic film or a metal-containing film that defines at least one opening on the dielectric film.

14. the etching step includes providing an electrical bias to the substrate support; a period during which the electrical bias is applied to the substrate support includes a first period and a second period alternating with the first period; 14. The substrate processing method of claim 1, wherein the electrical bias during the first period is 0 or a first level, and the electrical bias during the second period is a second level greater than the first level.

15. the etching step includes supplying high frequency power to generate plasma to the substrate support or an upper electrode facing the substrate support; the period during which the high frequency power is supplied includes a third period and a fourth period alternating with the third period, a level of the high frequency power in the third period is 0 or a third level, and a level of the high frequency power in the fourth period is a fourth level that is greater than the third level, The second period and the fourth period at least partially overlap each other. The method of claim 14.

16. The method of claim 14 or 15, wherein the electrical bias is a pulse voltage.

17. 17. The substrate processing method according to claim 1, wherein the etching step includes supplying a DC voltage or a low-frequency power to an upper electrode facing the substrate support.

18. The etching step includes: a first step of etching the dielectric film by providing a first pressure in the chamber and a first electrical bias to the substrate support; a second step of etching the dielectric film by providing a second pressure in the chamber and a second electrical bias to the substrate support; Including, 18. The method of claim 1, wherein the first pressure is different from the second pressure and / or the first electrical bias is different from the second electrical bias.

19. 20. The method of claim 18, wherein the first pressure is greater than the second pressure.

20. 20. The method of claim 18, wherein an absolute value of the magnitude of the first electrical bias is greater than an absolute value of the magnitude of the second electrical bias.

21. 21. The substrate processing method according to claim 18, wherein the first step and the second step are alternately repeated.

22. The method includes the steps of: a chamber; a substrate support that is provided in the chamber and configured to be temperature adjustable; a plasma generating unit that supplies power for generating plasma in the chamber; and a control unit, The control unit controls a plasma generation unit to generate a plasma of HF gas and C by power supplied from the plasma generation unit in order to etch a dielectric film of a substrate supported on the substrate support through a mask that defines at least one opening on the dielectric film. 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 At least one C gas selected from the group consisting of x H y F z A control is performed to generate plasma by introducing a reactive gas containing a C gas into the chamber, and in the control, the temperature of the substrate support is set to 0° C. or less, and the flow rate of the HF gas is set to the C x H y F z The substrate processing apparatus has a flow rate greater than that of the gas.

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