Plasma processing apparatus and etching method

Abstract

The plasma processing apparatus of the present invention comprises: a plasma processing chamber; comprising a lower electrode, an electrostatic chuck and an edge ring; an upper electrode disposed above the substrate support; a generation source RF power supply that supplies generation source RF electric power to the upper electrode or the lower electrode; a bias power supply for supplying bias electric power to the lower electrode; a DC power source that applies a negative DC voltage to the edge ring; an RF filter including at least one variable passive element electrically connected between the edge ring and the DC power source; and a control unit configured to be able to control the DC power source and the variable passive element so as to control an incident angle of ions in the plasma with respect to an edge region of a substrate placed on the electrostatic chuck, and to control a voltage of the bias electric power within an allowable range.

Description

Technical Field

[0001] The present invention relates to a plasma processing device and an etching method. Background Art

[0002] Patent document 1 discloses a plasma processing device for performing plasma processing on a wafer, comprising: a stage for placing the wafer disposed in a chamber; and an edge ring disposed on the stage so as to surround the wafer. In the plasma processing device, a negative DC voltage is applied to the edge ring consumed by plasma to eliminate the deformation of the sheath, so that ions are vertically incident on the entire surface of the wafer.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-227063 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The technology of the present invention appropriately controls the voltage of bias electric power in plasma processing.

[0008] Technical solutions for solving technical problems

[0009] A plasma processing apparatus according to one embodiment of the present invention includes: a plasma processing chamber; a substrate support body arranged in the plasma processing chamber, the substrate support body including a lower electrode, an electrostatic chuck, and an edge ring arranged in a manner to surround a substrate placed on the electrostatic chuck; an upper electrode arranged above the substrate support body; a generating source RF power supply configured to supply generating source RF electric power to the upper electrode or the lower electrode to generate plasma from gas in the plasma processing chamber; a bias power supply configured to supply bias electric power to the lower electrode; a DC power supply configured to apply a negative DC voltage to the edge ring; an RF filter including at least one variable passive component electrically connected between the edge ring and the DC power supply; and a control unit configured to control the DC power supply and the variable passive component to control the incident angle of ions in the plasma relative to the edge region of the substrate placed on the electrostatic chuck and to control the voltage of the bias electric power within an allowable range.

[0010] Effects of the Invention

[0011] According to the present invention, the voltage of bias power can be appropriately controlled during plasma processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a longitudinal sectional view showing the outline of the structure of the etching device according to the present embodiment.

[0013] Figure 2 It is an explanatory diagram of a power supply system of the etching device according to this embodiment.

[0014] Figure 3A It is an explanatory diagram showing the change in the shape of the sheath and the occurrence of the tilt in the incident direction of ions due to the consumption of the edge ring.

[0015] Figure 3B It is an explanatory diagram showing the change in the shape of the sheath and the occurrence of the tilt in the incident direction of ions due to the consumption of the edge ring.

[0016] Figure 4A It is an explanatory diagram showing the change in the shape of the sheath and the inclination of the incident direction of ions.

[0017] Figure 4B It is an explanatory diagram showing the change in the shape of the sheath and the inclination of the incident direction of ions.

[0018] Figure 5 It is an explanatory diagram showing the relationship between the DC voltage from the DC power supply or the impedance of the second RF filter and the tilt correction angle.

[0019] Figure 6 It is an explanatory diagram showing the relationship between the DC voltage from the DC power supply or the impedance of the second RF filter and LF Vpp.

[0020] Figure 7 It is an explanatory diagram showing the relationship among the thickness of the edge ring, the DC voltage from the DC power supply, the impedance of the second RF filter, and LFVpp.

[0021] Figure 8 It is an explanatory diagram showing an example of a method of adjusting the DC voltage from the DC power supply and the impedance of the second RF filter.

[0022] Fig. 9 It is an explanatory diagram showing an example of a method of adjusting the DC voltage from the DC power supply and the impedance of the second RF filter.

[0023] Fig.10 It is an explanatory diagram showing an example of a method of adjusting the DC voltage from the DC power supply and the impedance of the second RF filter.

[0024] Fig.11 It is a longitudinal sectional view showing the structure of a connection portion according to another embodiment.

[0025] Fig.12This is an explanatory diagram showing a sensor for LF Vpp control in an etching device.

[0026] Fig.13 It is an explanatory diagram of a power supply system of an etching device according to another embodiment.

[0027] Fig.14 It is a longitudinal sectional view showing the structure of a connection portion according to another embodiment. DETAILED DESCRIPTION

[0028] In the manufacturing process of semiconductor devices, a semiconductor wafer (hereinafter referred to as a "wafer") is subjected to plasma processing such as etching. In the plasma processing, a processing gas is excited to generate plasma, and the wafer is processed using the plasma.

[0029] Plasma processing is performed in a plasma processing device. The plasma processing device generally includes a chamber, a workbench, and a radio frequency (RF) power supply. In one example, the RF power supply includes a source RF power supply and a bias RF power supply. The source RF power supply supplies source RF electric power to generate plasma of the gas in the chamber. The bias RF power supply supplies bias RF electric power to attract ions to the wafer. The workbench is arranged in the chamber. The workbench includes a lower electrode and an electrostatic chuck. In one example, an edge ring is arranged on the electrostatic chuck in a manner to surround a wafer placed on the electrostatic chuck. The edge ring is provided to improve the uniformity of plasma processing on the wafer.

[0030] The edge ring is consumed as the plasma treatment is performed, and the thickness of the edge ring is reduced. When the thickness of the edge ring is reduced, the shape of the sheath changes above the edge ring and the edge region of the wafer. When the sheath shape changes in this way, the incident direction of ions at the edge region of the wafer is tilted relative to the longitudinal direction. As a result, the concave portion formed in the edge region of the wafer is tilted relative to the thickness direction of the wafer.

[0031] In order to form a concave portion extending in the thickness direction of the wafer at the edge region of the wafer, it is necessary to control the shape of the sheath above the edge ring and the edge region of the wafer to adjust the inclination of the incident direction of ions to the edge region of the wafer. Therefore, in order to control the shape of the sheath above the edge ring and the edge region of the wafer, for example, Patent Document 1 proposes a plasma processing apparatus configured to apply a negative DC voltage from a DC power supply to the edge ring.

[0032] However, after in-depth research, the inventors found that, for example, when the DC voltage is increased to adjust the tilt of the incident direction of ions, the voltage Vpp of the bias RF power will increase. However, the method for adjusting the voltage Vpp has always been to adjust the RF power, but this RF power adjustment may affect the heat of the wafer and the process performance.

[0033] The technology of the present invention appropriately controls the voltage of bias electric power in plasma processing.

[0034] Hereinafter, an etching device and an etching method as a plasma processing device according to the present embodiment will be described with reference to the accompanying drawings. In this specification and the accompanying drawings, elements having substantially the same functional configuration are denoted by the same reference numerals and repeated descriptions are omitted.

[0035] <Etching equipment>

[0036] First, the etching apparatus according to this embodiment will be described. Figure 1 It is a longitudinal sectional view schematically showing the structure of the etching device 1 . Figure 2 1 is an explanatory diagram of a power supply system of an etching device 1. The etching device 1 is a capacitive coupling type etching device. The etching device 1 etches a wafer W as a substrate.

[0037] like Figure 1 As shown, the etching apparatus 1 includes a substantially cylindrical plasma processing chamber 10. The plasma processing chamber 10 has a processing space S formed therein for generating plasma. The plasma processing chamber 10 is made of, for example, aluminum. The plasma processing chamber 10 is connected to a ground potential.

[0038] A worktable 11 as a substrate support for mounting a wafer W is provided inside the plasma processing chamber 10. The worktable 11 includes a lower electrode 12, an electrostatic chuck 13, and an edge ring 14. In addition, an electrode plate (not shown) made of, for example, aluminum may be provided on the lower surface side of the lower electrode 12.

[0039] The lower electrode 12 is made of a conductive material, for example, a metal such as aluminum, and has a substantially disk shape.

[0040] In addition, the workbench 11 may further include a temperature adjustment module for adjusting at least one of the electrostatic chuck 13, the edge ring 14, and the wafer W to a desired temperature. The temperature adjustment module may include a heater, a flow path, or a combination thereof. A temperature adjustment medium such as a coolant or a heat transfer gas may flow in the flow path.

[0041] In one example, a flow path 15a is formed inside the lower electrode 12. A temperature control medium is supplied to the flow path 15a from a cooling unit (not shown) provided outside the plasma processing chamber 10 via an inlet pipe 15b. The temperature control medium supplied to the flow path 15a is returned to the cooling unit via an outlet flow path 15c. By circulating a temperature control medium such as cooling water in the flow path 15a, the electrostatic chuck 13, the edge ring 14, and the wafer W can be cooled to a desired temperature.

[0042] The electrostatic chuck 13 is provided on the lower electrode 12. In one example, the electrostatic chuck 13 is a component capable of holding both the wafer W and the edge ring 14 by electrostatic force. The upper surface of the central portion of the electrostatic chuck 13 is formed to be higher than the upper surface of the peripheral portion. The upper surface of the central portion of the electrostatic chuck 13 is a wafer mounting surface capable of mounting the wafer W, and in one example, the upper surface of the peripheral portion of the electrostatic chuck 13 is an edge ring mounting surface capable of mounting the edge ring 14.

[0043] In one example, a first electrode 16a for adsorbing and holding the wafer W is provided at the center of the electrostatic chuck 13. A second electrode 16b for adsorbing and holding the edge ring 14 is provided at the periphery of the electrostatic chuck 13. The electrostatic chuck 13 has a structure in which the electrodes 16a and 16b are sandwiched between insulating members made of insulating materials.

[0044] A DC voltage from a DC power supply (not shown) is applied to the first electrode 16a. The electrostatic force generated thereby adsorbs and holds the wafer W on the upper surface of the central portion of the electrostatic chuck 13. Similarly, a DC voltage from a DC power supply (not shown) is applied to the second electrode 16b. In one example, the electrostatic force generated thereby adsorbs and holds the edge ring 14 on the upper surface of the peripheral portion of the electrostatic chuck 13.

[0045] In addition, in this embodiment, the central portion of the electrostatic chuck 13 where the first electrode 16a is provided and the peripheral portion where the second electrode 16b is provided are formed integrally, but the central portion and the peripheral portion may be separate. In addition, the first electrode 16a and the second electrode 16b may be monopolar or bipolar.

[0046] In addition, in the present embodiment, the edge ring 14 is electrostatically attracted by the electrostatic chuck 13 by applying a DC voltage to the second electrode 16b, but the method for holding the edge ring 14 is not limited thereto. For example, the edge ring 14 may be attracted and attracted by an adsorption sheet, or may be held by clamping. Alternatively, the edge ring 14 may be held by its own weight.

[0047] The edge ring 14 is an annular member arranged to surround the wafer W placed on the upper surface of the central portion of the electrostatic chuck 13. The edge ring 14 is provided to improve the uniformity of etching. Therefore, the edge ring 14 is made of a material appropriately selected according to etching, for example, it can be made of Si or SiC.

[0048] The stage 11 configured as described above is fixed to a substantially cylindrical support member 17 provided at the bottom of the plasma processing chamber 10. The support member 17 is made of an insulator such as ceramics or quartz.

[0049] A shower head 20 is provided above the workbench 11 in a manner opposite to the workbench 11. The shower head 20 includes an electrode plate 21 disposed facing the processing space S, and an electrode support 22 provided above the electrode plate 21. The electrode plate 21 and the lower electrode 12 function as a pair of upper electrodes. As described later, when the generating source RF power supply 50 is electrically coupled to the lower electrode 12, the shower head 20 is connected to the ground potential. In addition, the shower head 20 is supported on the upper portion (top surface) of the plasma processing chamber 10 via an insulating shielding member 23.

[0050] The electrode plate 21 has a plurality of gas ejection ports 21 a for supplying a processing gas sent from a gas diffusion space 22 a described later to the processing space S. The electrode plate 21 is made of, for example, a conductor or semiconductor having a low resistivity that generates little Joule heat.

[0051] The electrode support 22 supports the electrode plate 21 in a manner that the electrode plate 21 can be detached. The electrode support 22 has a structure in which a plasma-resistant film is formed on the surface of a conductive material such as aluminum. The film can be a film formed by anodizing, or a film made of ceramics such as yttrium oxide. A gas diffusion chamber 22a is formed inside the electrode support 22. A plurality of gas flow holes 22b are formed that are connected from the gas diffusion chamber 22a to the gas outlet 21a. In addition, a gas inlet hole 22c connected to a gas supply pipe 33 described later is formed in the gas diffusion chamber 22a.

[0052] Furthermore, a gas supply source group 30 for supplying a processing gas to the gas diffusion space 22 a is connected to the electrode support 22 via a flow control device group 31 , a valve group 32 , a gas supply pipe 33 , and a gas introduction hole 22 c .

[0053] The gas supply source group 30 includes a plurality of gas supply sources required for etching. The flow control device group 31 includes a plurality of flow controllers, and the valve group 32 includes a plurality of valves. The plurality of flow controllers of the flow control device group 31 can each be a mass flow controller or a pressure-controlled flow controller. In the etching device 1, the processing gas from one or more gas supply sources selected from the gas supply source group 30 is supplied to the gas diffusion chamber 22a via the flow control device group 31, the valve group 32, the gas supply pipe 33 and the gas introduction hole 22c. The processing gas supplied to the gas diffusion chamber 22a is supplied to the processing space S in a dispersed manner in a spray shape via the gas flow hole 22b and the gas ejection port 21a.

[0054] A buffer plate 40 is provided at the bottom of the plasma processing chamber 10 and between the inner wall of the plasma processing chamber 10 and the support member 17. The buffer plate 40 is formed by, for example, covering an aluminum material with a ceramic such as yttrium oxide. A plurality of through holes are formed in the buffer plate 40. The processing space S is connected to an exhaust port 41 via the buffer plate 40. An exhaust device 42 such as a vacuum pump is connected to the exhaust port 41, and the exhaust device 42 can reduce the pressure in the processing space S.

[0055] Furthermore, a wafer W loading and unloading port 43 is formed on a side wall of the plasma processing chamber 10 , and the wafer W loading and unloading port 43 can be opened and closed by a shutter 44 .

[0056] like Figure 1 and Figure 2 As shown, the etching apparatus 1 further includes a generating source RF power source 50, a bias RF power source 51, and a matching device 52. The generating source RF power source 50 and the bias RF power source 51 are coupled to the lower electrode 12 via the matching device 52.

[0057] The generation source RF power source 50 generates a generation source RF electric power HF for plasma generation, and supplies the generation source RF electric power HF to the lower electrode 12. The generation source RF electric power HF may have a frequency in the range of 27 MHz to 100 MHz, and in one example, 40 MHz. The generation source RF power source 50 is coupled to the lower electrode 12 via the first matching circuit 53 of the matching device 52. The first matching circuit 53 is a circuit for matching the output impedance of the generation source RF power source 50 with the input impedance of the load side (lower electrode 12 side). In addition, the generation source RF power source 50 may be coupled to the shower head 20 as the upper electrode via the first matching circuit 53 instead of being electrically coupled to the lower electrode 12. In addition, a pulse power source may be used instead of the generation source RF power source 50, and the pulse power source is configured to be able to apply a pulse voltage other than the generation source RF electric power HF to the lower electrode 12. This pulse power source is the same as the pulse power source used instead of the bias RF power source 51 described later.

[0058] The bias RF power supply 51 generates bias RF power LF for attracting ions to the wafer W, and supplies the bias RF power LF to the lower electrode 12. The bias RF power LF may be a frequency in the range of 400 kHz to 13.56 MHz, and in one example, 400 kHz. The bias RF power supply 51 is coupled to the lower electrode 12 via the second matching circuit 54 of the matcher 52. The second matching circuit 54 is a circuit for matching the output impedance of the bias RF power supply 51 with the input impedance of the load side (lower electrode 12 side). In addition, a pulse power supply may be used instead of the bias RF power supply 51, and the pulse power supply may be configured to apply a pulse voltage other than the bias RF power LF to the lower electrode 12. Here, the pulse voltage refers to a pulse voltage whose magnitude changes periodically. The pulse power supply may be a DC power supply. The pulse power supply may be configured so that the power supply itself can apply a pulse voltage, or may be configured so that a device for pulsing the voltage is provided on the downstream side. For example, a pulse voltage may be applied to the lower electrode 12 to generate a negative potential on the wafer W. The pulse voltage may be a rectangular wave, a triangular wave, a pulse wave or other waveforms. The frequency of the pulse voltage (pulse frequency) may be a frequency in the range of 100kHz to 2MHz. In addition, the bias RF power LF or the pulse voltage may also be supplied or applied to a bias electrode disposed inside the electrostatic chuck 13.

[0059] The etching device 1 further includes a direct current (DC) power supply 60, a switching unit 61, a first RF filter 62, and a second RF filter 63. The DC power supply 60 is electrically connected to the edge ring 14 via the switching unit 61, the second RF filter 63, and the first RF filter 62. In addition, in the present embodiment, the DC power supply 60 is connected to the ground potential.

[0060] The DC power source 60 is a power source that generates a negative-polarity DC voltage to be applied to the edge ring 14. The DC power source 60 is a variable DC power source, and the level of the DC voltage can be adjusted.

[0061] The switching unit 61 is configured to stop the application of the DC voltage from the DC power supply 60 to the edge ring 14. In addition, the circuit structure of the switching unit 61 can be appropriately designed by those skilled in the art.

[0062] The first RF filter 62 and the second RF filter 63 are filters for attenuating RF power. The first RF filter 62 attenuates, for example, 40 MHz of the source RF power HF from the source RF power source 50. The second RF filter 63 attenuates, for example, 400 kHz of the bias RF power LF from the bias RF power source 51.

[0063] In one example, the second RF filter 63 is configured to have a variable impedance. That is, the second RF filter 63 includes at least one variable passive element, and the impedance is variable. In the following description, the impedance of the second RF filter 63 is synonymous with the impedance of the variable passive element. The second variable passive element can be, for example, any one of a coil (inductor) or a capacitor (condenser, capacitor). In addition, it is not limited to coils and capacitors. If it is a variable impedance element such as a diode or other element, any element can achieve the same function. The number and position of the variable passive elements can also be appropriately designed by those skilled in the art. In addition, the element itself does not need to be variable. For example, a plurality of elements with fixed impedance values ​​can be provided, and the impedance can be made variable by using a switching circuit to switch the combination of elements with fixed values. In addition, the circuit structure of the second RF filter 63 and the above-mentioned first RF filter 62 can also be appropriately designed by those skilled in the art.

[0064] The etching apparatus 1 may further include a measuring device (not shown) for measuring the self-bias voltage of the edge ring 14 (or the self-bias voltage of the lower electrode 12 or the wafer W). The structure of the measuring device can be appropriately designed by a person skilled in the art.

[0065] The above etching device 1 is provided with a control unit 100. The control unit 100 is, for example, a computer having a CPU, a memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling etching in the etching device 1. In addition, the above program can be recorded in a computer-readable storage medium and installed from the storage medium to the control unit 100. In addition, the above storage medium can be volatile or non-volatile.

[0066] <Etching method>

[0067] Next, etching performed using the etching apparatus 1 configured as described above will be described.

[0068] First, a wafer W is introduced into the plasma processing chamber 10 and placed on the electrostatic chuck 13. Then, a DC voltage is applied to the first electrode 16a of the electrostatic chuck 13, so that the wafer W is electrostatically attracted and held on the electrostatic chuck 13 by the Coulomb force. After the wafer W is introduced, the interior of the plasma processing chamber 10 is depressurized to a desired vacuum level by the exhaust device 42.

[0069] Next, the processing gas is supplied from the gas supply source group 30 to the processing space S via the shower head 20. In addition, the processing gas is excited to generate plasma by supplying the generating source RF power HF for generating plasma to the lower electrode 12 by the generating source RF power supply 50. At this time, the bias RF power LF for attracting ions may also be supplied by the bias RF power supply 51. The wafer W is etched by the action of the generated plasma.

[0070] When etching is terminated, first, the supply of the source RF power HF from the source RF power source 50 and the supply of the processing gas from the gas supply source group 30 are stopped. In addition, if the bias RF power LF is supplied during etching, the supply of the bias RF power LF is also stopped. Next, the supply of the heat transfer gas to the back side of the wafer W is stopped, and the electrostatic chuck 13 stops adsorbing and holding the wafer W.

[0071] Then, the wafer W is carried out from the plasma processing chamber 10 , and a series of etching processes on the wafer W are completed.

[0072] In addition, during etching, plasma may be generated using only the bias RF power LF from the bias RF power source 51 without using the generation source RF power HF from the generation source RF power source 50 .

[0073] <Tilt angle control method>

[0074] Next, a method for controlling the tilt angle in the above-mentioned etching is described. The tilt angle refers to the tilt (angle) of the recess formed by etching in the edge region of the wafer W relative to the thickness direction of the wafer W. The tilt angle is an angle that is approximately the same as the tilt angle (incident angle of the ions) of the incident direction of the edge region of the wafer W relative to the longitudinal direction. In addition, in the following description, the radial inner side (center side) direction relative to the thickness direction (longitudinal direction) of the wafer W is referred to as the inner side, and the radial outer side direction relative to the thickness direction of the wafer W is referred to as the outer side.

[0075] Figure 3A and Figure 3B It is an explanatory diagram showing the change in the shape of the sheath and the generation of the tilt in the ion incident direction due to the consumption of the edge ring. Figure 3A The edge ring 14 indicated by the solid line in the figure represents the edge ring 14 without the consumption. The edge ring 14 indicated by the dotted line represents the edge ring 14 with the consumption and reduced thickness. Figure 3A The sheath SH indicated by the solid line in the figure shows the shape of the sheath SH when the edge ring 14 is not consumed. The sheath SH indicated by the dotted line shows the shape of the sheath SH when the edge ring 14 is consumed. Figure 3AThe middle arrow indicates the incident direction of ions when the edge ring 14 is in a consumed state.

[0076] like Figure 3A As shown, in one example, when the edge ring 14 is in an unconsumed state, the shape of the sheath SH remains flat above the wafer W and the edge ring 14. Therefore, ions are incident in a direction (longitudinal direction) substantially perpendicular to the entire surface of the wafer W. Therefore, the tilt angle is 0 (zero) degree.

[0077] On the other hand, when the edge ring 14 is consumed and its thickness is reduced, the thickness of the sheath SH decreases in the edge region of the wafer W and above the edge ring 14, and the shape of the sheath SH becomes convex downward. As a result, the incident direction of ions to the edge region of the wafer W is tilted relative to the longitudinal direction. In the following description, the phenomenon that the concave portion formed by etching tilts inward when the incident direction of ions is tilted radially inward (center side) relative to the longitudinal direction is referred to as inner tilt. Figure 3B In the embodiment, the incident direction of ions is tilted inward by an angle θ1, and the concave portion is also tilted inward by an angle θ1. The cause of the inclination is not limited to the consumption of the edge ring 14 described above. For example, when the bias voltage generated in the edge ring 14 is lower than the voltage on the wafer W side, the inclination occurs in the initial state. In addition, for example, the edge ring 14 is sometimes intentionally adjusted to be inward in the initial state, and the tilt angle is corrected by adjusting at least one of the DC voltage from the DC power supply 60 described later and the impedance of the second RF filter 63.

[0078] In addition, if Figure 4A and Figure 4B As shown, sometimes the thickness of the sheath SH becomes larger in the edge region of the wafer W and above the edge ring 14 relative to the central region of the wafer W, and the shape of the sheath SH becomes convex. For example, when the bias voltage generated at the edge ring 14 is high, the shape of the sheath SH may become convex. Figure 4A The arrow in shows the incident direction of ions. In the following description, when the incident direction of ions is tilted radially outward relative to the longitudinal direction, the phenomenon that the recessed portion formed by etching is tilted outward is referred to as Outer Tilt. Figure 4B In the figure, the incident direction of the ions is tilted outward by an angle θ2, and the recess is also tilted outward by θ2.

[0079] In the etching apparatus 1 of the present embodiment, the tilt angle is controlled. Specifically, the tilt angle is controlled by adjusting at least one of the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63 to control the incident angle of ions.

[0080] [DC voltage regulation]

[0081] First, the adjustment of the DC voltage from the DC power supply 60 is described. In the DC power supply 60, the DC voltage applied to the edge ring 14 is set to a voltage having a negative polarity whose absolute value is the sum of the absolute value of the self-bias voltage Vdc and the set value ΔV, that is, -(|Vdc|+ΔV). The self-bias voltage Vdc is the self-bias voltage of the wafer W, and is the self-bias voltage of the lower electrode 12 when at least any RF power is supplied and the DC voltage from the DC power supply 60 is not applied to the lower electrode 12. The set value ΔV is given by the control unit 100.

[0082] The control unit 100 uses a predetermined function or table to determine the set value ΔV based on the consumption of the edge ring 14 (the amount of reduction in the thickness of the edge ring 14 from the initial value) and the consumption of the edge ring 14 estimated from the etching process conditions (e.g., processing time). That is, the control unit 100 determines the set value ΔV by inputting the consumption of the edge ring 14 and the self-bias voltage into the above function or by referring to the above table using the consumption of the edge ring 14 and the self-bias voltage.

[0083] When determining the set value ΔV, the control unit 100 may use the difference between the initial thickness of the edge ring 14 and the thickness of the edge ring 14 actually measured by a measuring instrument such as a laser measuring instrument or a camera as the consumption of the edge ring 14. In addition, for example, the consumption of the edge ring 14 may be estimated based on the mass change of the edge ring 14 measured by a measuring instrument such as a mass meter. Alternatively, the control unit 100 may estimate the consumption of the edge ring 14 based on a specific parameter using another predetermined function or table to determine the set value ΔV. The specific parameter may be any of the self-bias voltage Vdc, the voltage Vpp of the generated source RF power HF or the bias RF power LF, the load impedance, and the electrical characteristics of the edge ring 14 or the periphery of the edge ring 14. The electrical characteristics of the edge ring 14 or the periphery of the edge ring 14 may be any of the voltage, current value, and resistance value including the edge ring 14 at any part of the edge ring 14 or the periphery of the edge ring 14. Another function or table is predetermined in advance to determine the relationship between the specific parameter and the consumption of the edge ring 14. In order to estimate the consumption of the edge ring 14, before the actual etching is performed or when the etching apparatus 1 is maintained, the etching apparatus 1 is operated under the measurement conditions for estimating the consumption, that is, the settings of the generated source RF power HF, the bias RF power LF, the pressure in the processing space S, and the flow rate of the processing gas supplied to the processing space S. Then, the above-mentioned specific parameters are obtained, and the consumption of the edge ring 14 can be determined by inputting the specific parameters into the above-mentioned other functions or referring to the above-mentioned table using the specific parameters.

[0084] In the etching apparatus 1, during etching, that is, during a period in which at least one of the source RF power HF and the bias RF power LF is supplied, a DC voltage is applied from the DC power supply 60 to the edge ring 14. Thus, the sheath shape above the edge ring 14 and the edge region of the wafer W is controlled, the inclination of the incident direction of ions to the edge region of the wafer W is reduced, and the inclination angle is controlled. As a result, a recessed portion substantially parallel to the thickness direction of the wafer W is formed in the entire region of the wafer W.

[0085] In more detail, during etching, the self-bias voltage Vdc is measured by a measuring instrument (not shown). In addition, a DC voltage is applied to the edge ring 14 from the DC power supply 60. The value of the DC voltage applied to the edge ring 14 is -(|Vdc|+ΔV) as described above. |Vdc| is the absolute value of the measured value of the self-bias voltage Vdc just obtained by the measuring instrument, and ΔV is a set value determined by the control unit 100. In this way, the DC voltage applied to the edge ring 14 is determined according to the measured self-bias voltage Vdc during etching. In this way, even if the self-bias voltage Vdc changes, the DC voltage generated by the DC power supply 60 will be corrected, and the tilt angle will be appropriately corrected.

[0086] [Impedance adjustment]

[0087] Next, adjustment of the impedance of the second RF filter 63 will be described.

[0088] The control unit 100 sets the impedance of the second RF filter 63 according to the consumption of the edge ring 14, similarly to the setting of the DC voltage from the DC power supply 60. The control unit 100 changes the voltage generated in the edge ring 14 by changing the impedance of the second RF filter 63.

[0089] In the etching apparatus 1, during etching, the control unit 100 controls the second RF filter 63 to a set impedance. Thus, the sheath shape above the edge ring 14 and the edge region of the wafer W is controlled, and the inclination of the incident direction of ions to the edge region of the wafer W can be reduced, thereby controlling the inclination angle.

[0090] [Adjustment of DC voltage and impedance]

[0091] Figure 5 It is an explanatory diagram showing the relationship between the DC voltage from the DC power supply 60 or the impedance of the second RF filter 63 and the correction angle of the tilt angle (hereinafter referred to as “tilt correction angle”). Figure 5 The vertical axis represents the tilt correction angle, and the horizontal axis represents the DC voltage or impedance. Figure 5 As shown in FIG. 1 , when the absolute value of the DC voltage from the DC power supply 60 is increased, the tilt correction angle becomes larger. In addition, when the impedance of the second RF filter 63 is increased, the tilt correction angle also becomes larger. Figure 5In the example shown, although the tilt correction angle is increased by increasing the impedance, the tilt correction angle can also be reduced by increasing the impedance according to the structure of the second RF filter 63. The relationship between the impedance and the tilt correction angle depends on the design of the second RF filter 63 and is not limited thereto. In addition, the resolution of the tilt angle correction performed by the DC voltage adjustment ( Figure 5 The slope in the figure) and the resolution of the tilt angle correction based on impedance adjustment ( Figure 5 The slope in (i) depends on the performance of the DC power supply 60 and the second RF filter 63, etc. The resolution of the tilt angle correction refers to the tilt angle correction amount in one adjustment of the DC voltage or impedance.

[0092] Therefore, the tilt angle is controlled by adjusting the DC voltage from the DC power supply 60 and adjusting the impedance of the second RF filter 63 in any combination according to the consumption of the edge ring 14. For example, the tilt angle may be controlled by adjusting only the DC voltage from the DC power supply 60, or by adjusting only the impedance of the second RF filter 63. In addition, the tilt angle may be controlled by adjusting both the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63 at the same time.

[0093] Specifically, for example Figure 3A and Figure 3B As shown in FIG. 1 , when the edge ring 14 is consumed, the incident angle of the ions is tilted inward relative to the longitudinal direction, and an inward tilt occurs. Figure 5 As shown, the tilt correction angle increases when at least one of the absolute value of the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63 is increased. Thus, the tilt angle tilted inward can be changed outward and corrected to 0 (zero) degrees.

[0094] In addition, in the present embodiment, at least one of the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63 is adjusted according to the consumption of the edge ring 14, but the timing of adjusting the DC voltage or impedance is not limited thereto. For example, the DC voltage or impedance may be adjusted according to the processing time of the wafer W. Alternatively, for example, the processing time of the wafer W and a predetermined parameter such as high-frequency electric power may be combined to determine the timing of adjusting the DC voltage or impedance.

[0095] <Voltage Vpp Control Method of Bias RF Power LF>

[0096] Next, a method of controlling the voltage Vpp of the bias RF power LF (hereinafter referred to as “LF Vpp”) in the above-mentioned etching will be described.

[0097] Figure 6It is an explanatory diagram showing the relationship between the DC voltage from the DC power supply 60 or the impedance of the second RF filter 63 and the LF Vpp. Figure 6 The vertical axis represents LF Vpp, and the horizontal axis represents DC voltage or impedance. The inventors of the present invention have conducted in-depth research and found that Figure 6 As shown in FIG. 1 , when the absolute value of the DC voltage from the DC power supply 60 is increased, the LF Vpp is increased, but when the impedance of the second RF filter 63 is increased, the LF Vpp is decreased. That is, by adjusting the impedance of the second RF filter 63, not only the tilt angle but also the LF Vpp can be controlled. Based on this finding, the LF Vpp is controlled.

[0098] During etching by the etching device 1, for example, Figure 7 As shown in (a), as the edge ring 14 is consumed and the thickness of the edge ring 14 decreases, the absolute value of the DC voltage from the DC power supply 60 is increased. The DC voltage is determined according to the controllability of the tilt angle. When the absolute value of the DC voltage is increased in this way, the LF Vpp increases.

[0099] So, if Figure 7 As shown in (b), when the DC voltage is increased, the impedance of the second RF filter 63 is also increased. When the impedance is increased like this, according to Figure 6 The relationship shown in FIG. 1 is that the LF Vpp decreases. That is, the increase in LF Vpp caused by the DC voltage adjustment is offset by the decrease in LF Vpp caused by the impedance adjustment. In this way, the LF Vpp can be controlled to be constant or within an allowable range. The allowable range can be arbitrarily set according to the specifications required by the etching process.

[0100] According to this embodiment, the tilt angle is controlled by adjusting the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63, and the LF Vpp can also be appropriately adjusted by adjusting the impedance. That is, the LF Vpp can be controlled in the tilt angle control. Moreover, such control can be achieved without changing the device structure.

[0101] In addition, as described above, in the prior art, LF Vpp is adjusted by adjusting RF power, but the adjustment of RF power may affect the heating of the wafer and process performance. In this regard, according to this embodiment, LF Vpp can be adjusted by keeping RF power constant, thereby suppressing the influence on the heating of the wafer and process performance in the prior art.

[0102] In addition, in this embodiment, if Figure 6As shown in FIG. 1 , when the impedance of the second RF filter 63 is increased, the LF Vpp is reduced. However, depending on the circuit design of the second RF filter 63 and the measurement position of the LF Vpp, the LF Vpp may also be reduced when the impedance is reduced. Therefore, in order to reduce the LF Vpp, it is not necessary to increase the impedance of the second RF filter 63, and the impedance can be adjusted according to the circuit design of the second RF filter 63 and the measurement position of the LF Vpp.

[0103] <How to adjust DC voltage and impedance>

[0104] As described above, in this embodiment, the tilt angle and LF Vpp are controlled by adjusting the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63. At this time, the DC voltage adjustment and the impedance adjustment can be arbitrarily combined. An example is described below.

[0105] Figure 8 1 is an explanatory diagram showing an example of a method of adjusting the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63 . Figure 8 In the example, the absolute values ​​of the DC voltages V1, V2, V3, and V4 increase in sequence, and the impedances Z1, Z2, Z3, and Z4 decrease in sequence. In addition, “Edge ring New” indicates that the edge ring 14 is new and unconsumed, and “Edge ring Life Limit” indicates that the edge ring 14 is consumed to its life limit and needs to be replaced.

[0106] like Figure 8 As shown, the absolute value of the DC voltage changes from V1 to V3 and the impedance changes from Z3 to Z1 as the edge ring 14 is consumed. In this embodiment, these DC voltage and impedance are changed and adjusted simultaneously.

[0107] As the edge ring 14 is consumed, the incident angle of the ions tilts inwards. Figure 5 As shown in the figure, by increasing the absolute value of the DC voltage, the tilt correction angle increases. As a result, the tilt angle that is tilted inward can be changed to the outward, and the tilt angle can be corrected to 0 (zero) degrees. At this time, since the impedance is reduced, the tilt correction angle is reduced, but based on the reduction of the tilt correction angle, the absolute value of the DC voltage is changed so that the tilt angle is 0 (zero) degrees.

[0108] In addition, if Fig. 9 As shown, by increasing the DC voltage, the LF Vpp increases, and by increasing the impedance, the LF Vpp decreases, so that the LF Vpp can be controlled to be constant or within an allowable range. Fig. 9 The vertical axis represents LF Vpp, and the horizontal axis represents DC voltage or impedance.

[0109] As described above, the value of the DC voltage and the value of the impedance are set so that the tilt angle is 0 (zero) degrees and the LF Vpp is constant or within the allowable range. Thus, the tilt angle and the LF Vpp can be freely controlled.

[0110] In addition, in this embodiment, the DC voltage and the impedance are changed at the same time for adjustment, but they can also be adjusted separately. The timing of adjusting the DC voltage and the timing of adjusting the impedance are arbitrary. For example, the impedance can be adjusted after adjusting the DC voltage, or the DC voltage can be adjusted after adjusting the impedance. In any case, both the tilt angle and the LF Vpp are controlled.

[0111] In addition, in the present embodiment, the DC voltage and the impedance are adjusted, but the DC voltage from the DC power supply 60 may be in a non-output state, and the tilt angle and the LF Vpp may be controlled by adjusting only the impedance.

[0112] In addition, in this embodiment, the impedance is changed from Z3 to Z1 in one direction, but if Fig.10 As shown, the impedance can also be increased or decreased. Fig.10 The vertical axis represents the DC voltage or impedance, and the horizontal axis represents the device operation time (processing time). Fig.10 In FIG. 1 , the first arrow represents the change of the DC voltage and the impedance when the first wafer W is etched, and the second arrow represents the change of the DC voltage and the impedance when the second wafer W is etched.

[0113] Here, when the purpose is to control the tilt angle as in the prior art, the impedance is usually adjusted in one direction to increase the tilt correction angle. In contrast, when the LF Vpp is controlled to be constant or within an allowable range as in this embodiment, Fig.10 As shown by the double-headed arrow in , the impedance can be increased or decreased. In other words, the impedance can be adjusted independently of the consumption of the edge ring 14 and can be adjusted arbitrarily within a range where the tilt angle control is not affected. In addition to increasing due to changes in the DC voltage, the LF Vpp may also change due to reasons other than the DC voltage. Therefore, by increasing or decreasing the impedance in a manner that tracks the changes in the LF Vpp, the LF Vpp can always be controlled to be constant or within an allowable range.

[0114] In addition, in this embodiment, the starting point of the impedance is Z3, but this starting point can also be set arbitrarily. As described above, in this embodiment, the impedance can be increased or decreased, and in this case, the starting point can also be freely selected.

[0115] In addition, in this embodiment, the DC voltage and impedance are adjusted between etching one wafer W and etching the next wafer W, but the timing of adjusting the DC voltage and impedance is not limited thereto. For example, when the etching time for one wafer W is long and the edge ring 14 is consumed during etching, the DC voltage and impedance can be adjusted again during the etching.

[0116] <Other Implementation Methods>

[0117] As described above, the frequency of the bias RF power LF supplied from the bias RF power supply 51 is 400kHz to 13.56MHz, but is preferably 5MHz or less. When etching is performed on a wafer W with a high aspect ratio, high ion energy is required to achieve a vertical shape of the pattern after etching. Therefore, the inventors of the present invention have conducted intensive research and found that by setting the frequency of the bias RF power LF to 5MHz or less, the ion tracking performance of the ion to the change of the high-frequency electric field is improved, and the controllability of the ion energy is improved.

[0118] On the other hand, when the frequency of the bias RF power LF is set to a low frequency of 5 MHz or less, the effect of making the impedance of the second RF filter 63 variable may be reduced. That is, the controllability of controlling the tilt angle by adjusting the impedance of the second RF filter 63 may be reduced. Figure 2 In the embodiment, when the electrical connection between the edge ring 14 and the second RF filter 63 is non-contact or capacitive coupling, the tilt angle cannot be properly controlled even if the impedance of the second RF filter 63 is adjusted. Therefore, in the present embodiment, the edge ring 14 and the second RF filter 63 are directly electrically connected.

[0119] The edge ring 14 and the second RF filter 63 are directly electrically connected via a connection portion. The edge ring 14 contacts the connection portion, and a DC current from the DC power supply 60 is conducted through the connection portion. An example of the structure of the connection portion (hereinafter sometimes referred to as a "contact structure") is described below.

[0120] like Fig.11 As shown, the connection portion 200 as a conductor includes a conductive structure 201 and a conductive elastic component 202. The conductive structure 201 connects the edge ring 14 to the second RF filter 63 via the conductive elastic component 202. Specifically, one end of the conductive structure 201 is connected to the second RF filter 63, and the other end is exposed on the upper surface of the lower electrode 12 and contacts the conductive elastic component 202.

[0121] The conductive elastic component 202 is disposed, for example, on the side of the electrostatic chuck 13 in the space formed between the lower electrode 12 and the edge ring 14. The conductive elastic component 202 is in contact with the conductive structure 201 and the lower surface of the edge ring 14, respectively. In addition, the conductive elastic component 202 is composed of a conductor such as metal. The structure of the conductive elastic component 202 is not particularly limited, for example, reference can be made to Japanese Patent Publication No. 2022-7865. Fig.11 A~ Fig.11 The configuration of the conductive elastic component 202 in the top view is not particularly limited, and for example, reference can be made to Japanese Patent Publication No. 2022-7865. Fig.12 A~ Fig.12 The configuration shown in C.

[0122] In this case, if Fig.11 As shown, the edge ring 14 is directly electrically connected to the second RF filter 63 via the connection portion 200. Therefore, the frequency of the bias RF power LF can be set to a low frequency of 5 MHz or less, and the controllability of the ion energy can be improved. In addition, as described above, by adjusting the impedance of the second RF filter 63, the adjustment range of the tilt angle can be expanded, and the tilt angle can be controlled to a desired value.

[0123] In addition, the contact structure with the edge ring 14 is not limited to Fig.11 For example, reference can be made to Japanese Patent Publication No. 2022-7865. Fig.13 A~ Fig.13 G. In addition, the relationship between the connection portion 200 and the first RF filter 62 and the second RF filter 63 is not particularly limited. For example, reference can be made to Japanese Patent Publication No. 2022-7865. Fig.14 A~ Fig.14 The structure shown in C.

[0124] <Other Implementation Methods>

[0125] In the above embodiment, the DC power supply 60 is connected to the edge ring 14 via the switching unit 61, the first RF filter 62, and the second RF filter 63, but the power supply system for applying a DC voltage to the edge ring 14 is not limited thereto. For example, the DC power supply 60 may be electrically connected to the edge ring 14 via the switching unit 61, the second RF filter 63, the first RF filter 62, and the lower electrode 12. In this case, the lower electrode 12 is directly electrically coupled to the edge ring 14, and the self-bias voltage of the edge ring 14 is the same as the self-bias voltage of the lower electrode 12.

[0126] Here, when the lower electrode 12 is directly electrically coupled to the edge ring 14, for example, due to the capacity under the edge ring 14 determined by the hardware structure, the sheath thickness on the edge ring 14 cannot be adjusted, and outward tilt may occur even if the DC voltage is not applied. In contrast, in the present invention, the tilt angle can be controlled by adjusting the DC voltage from the DC power supply 60 and the impedance of the second RF filter 63, so that the tilt angle can be adjusted to 0 (zero) degrees by changing the tilt angle inward.

[0127] <Other Implementation Methods>

[0128] In the above embodiment, the generated RF power HF and the bias RF power supply 51 are used as RF power supplies, but the number of RF power supplies is not limited thereto. For example, there may be one RF power supply that supplies RF power of one frequency, or there may be three RF power supplies that supply RF power of three frequencies.

[0129] <Other Implementation Methods>

[0130] In the above embodiment, the impedance of the second RF filter 63 is made variable, but the impedance of the first RF filter 62 may be made variable, or the impedances of both the RF filters 62 and 63 may be made variable. In this case, the first RF filter 62 can attenuate the bias RF power LF, and the LF Vpp can be controlled by adjusting the impedance of the first RF filter 62. Alternatively, when it is necessary to control both the LF Vpp and the voltage Vpp of the generated source RF power HF (hereinafter referred to as "HF Vpp"), the HF Vpp can be controlled by adjusting the impedance of the first RF filter 62, and the LF Vpp can be controlled by adjusting the impedance of the second RF filter 63.

[0131] In the above embodiment, two RF filters 62 and 63 are provided for the DC power supply 60, but the number of RF filters is not limited thereto. For example, the two RF filters 62 and 63 may be integrated into one RF filter. Alternatively, three or more RF filters may be provided.

[0132] In addition, in the above embodiment, the second RF filter 63 (first RF filter 62) makes the impedance variable by including at least one variable passive element, but the structure that makes the impedance variable is not limited to this. For example, a device that can make the impedance of the RF filter 62, 63 variable can be connected to the RF filter 62, 63 with variable or fixed impedance. That is, the RF filter 62, 63 with variable impedance can be composed of an RF filter and a device that is connected to the RF filter and makes the impedance of the RF filter variable. In addition, the RF filter 62, 63 makes the impedance variable by including at least one variable passive element, but it is also possible to use a component with non-variable impedance in the RF filter 62, 63 and set a variable passive element outside the RF filter 62, 63.

[0133] <Other Implementation Methods>

[0134] In the above embodiment, the etching apparatus 1 may have a sensor for controlling the LF Vpp. Fig.12 1 is an explanatory diagram showing a sensor for controlling LF Vpp in the etching apparatus 1 .

[0135] like Fig.12 As shown, the etching device 1 includes a chamber sensor 300, a matching sensor 301, a DC power sensor 302, and a filter path sensor 303. Each sensor 300, 301, 302, 303 uses a sensor corresponding to the measurement object, such as a voltage sensor, a contact sensor, a non-contact sensor, an optical sensor, etc.

[0136] The in-chamber sensor 300 can measure, for example, the LF Vpp in the plasma processing chamber 10. In addition, the in-chamber sensor 300 can measure, for example, information about the LF Vpp in the plasma processing chamber 10, such as voltage, current (magnetic field), electric power, and device load information (including impedance, transmission electric power, reflected electric power, etc.). The LF Vpp can be calculated and estimated based on the information about the LF Vpp. The in-chamber sensor 300 can be set at any position in the plasma processing chamber 10, such as in the path connecting the matcher 52 to the plasma processing chamber 10, in the pipeline for supplying RF electric power, in the electrostatic chuck 13, etc. In addition, the in-chamber sensor 300 can also be set outside the plasma processing chamber 10. The information measured by the in-chamber sensor 300 is output to the control unit 100.

[0137] The matcher sensor 301 can measure, for example, the LF Vpp in the matcher 52. In addition, the matcher sensor 301 can measure, for example, information about the LF Vpp in the matcher 52, such as voltage, device load information (including impedance, transmission electric power, reflected electric power, etc.). The LF Vpp can be calculated and estimated based on the information about the LF Vpp. The matcher sensor 301 can be set at any position in the matcher 52, such as in the first matching circuit 53, in the second matching circuit 54, at the exit of the matching circuits 53 and 54, etc. In addition, the matcher sensor 301 can also be set outside the matcher 52. The information measured by the matcher sensor 301 is output to the control unit 100.

[0138] The DC power sensor 302 can measure information about the LF Vpp in the DC power supply 60, such as the DC voltage (output voltage), DC current (output current), high-frequency noise voltage, high-frequency noise current, etc. from the DC power supply 60. The LF Vpp can be calculated and estimated based on the information about the LF Vpp. The DC power sensor 302 can be provided inside or outside the DC power supply 60. The information measured by the DC power sensor 302 is output to the control unit 100.

[0139] The filter path sensor 303 can measure information about the LF Vpp in the filter path, such as voltage, current (magnetic field), etc. The LF Vpp can be calculated and estimated based on the information about the LF Vpp. The filter path sensor 303 can be set at any position in the filter path, such as in the path between the RF filters 62, 63 and the edge ring 14. In addition, the filter path sensor 303 can also be set in the RF filters 62, 63. The information measured by the filter path sensor 303 is output to the control unit 100.

[0140] The control unit 100 collects and processes the information output from the chamber sensor 300, the matching sensor 301, the DC power supply sensor 302, and the filter path sensor 303, and then outputs an instruction to the second RF filter 63. Specifically, when the input information is information about LF Vpp, the control unit 100 calculates LF Vpp based on the information. Based on the measured LF Vpp or the calculated LF Vpp, the impedance of the second RF filter 63 (variable passive element) is calculated. The calculated impedance is output to the second RF filter 63 to control the second RF filter 63.

[0141] In addition, in the present embodiment, although the control unit 100 is provided in the etching device 1, its configuration is arbitrary. For example, the control unit 100 may be provided as an integrated device separately from the etching device 1. In addition, the control unit 100 may be provided integrally with the second RF filter 63 and the variable passive element of the second RF filter 63, or may be provided separately in a plurality of parts.

[0142] According to the present embodiment, the impedance of the second RF filter 63 can be automatically adjusted based on information output from the in-chamber sensor 300 , the matching device sensor 301 , the DC power supply sensor 302 , and the filter path sensor 303 .

[0143] In addition, in this embodiment, although the chamber sensor 300, the matching device sensor 301, the DC power supply sensor 302, and the filter path sensor 303 are provided, the type and number of sensors are not limited thereto, and any sensor that can measure LF Vpp or information about LF Vpp can be used.

[0144] Alternatively, in order to estimate or measure information about the generated source RF electric power HF (e.g., load information, HF Vpp), the same sensor may be provided at each portion (e.g., the position of the sensors 300 to 303), and the information may be output to the control unit 100, and used to control the impedance of the RF filters 62 and 63. In addition, the positions of various sensors may be provided at any place depending on the measurement object. In addition, the above-mentioned information about the generated source RF electric power HF may also be used to control the LF Vpp.

[0145] In addition, in this embodiment, the chamber sensor 300, the matching sensor 301, the DC power sensor 302, and the filter path sensor 303 are not essential, and any one or all of them may be omitted. If all of these sensors are omitted, the operator may manually set the impedance of the second RF filter 63. Alternatively, after the operator sets the initial impedance, the control unit 100 may set the impedance according to the time of supplying RF power.

[0146] <Other embodiments>

[0147] In the etching device 1 of the above embodiment, the DC power supply 60, the switching unit 61, the first RF filter 62 and the second RF filter 63 may be replaced by Fig.13The first variable passive element 64 and the second variable passive element 65 are shown. That is, the etching device 1 does not have the DC power supply 60, and does not apply a negative DC voltage to the edge ring 14. The first variable passive element 64 and the second variable passive element 65 are arranged in sequence from the edge ring 14 side. The second variable passive element 65 is connected to the ground potential. That is, the second variable passive element 65 is not connected to any of the generating source RF power supply 50 and the bias RF power supply 51.

[0148] In one example, at least one of the first variable passive element 64 and the second variable passive element 65 is configured to have variable impedance. The first variable passive element 64 and the second variable passive element 65 can be, for example, any one of a coil (inductor) and a capacitor (condenser, capacitor). In addition, it is not limited to coils and capacitors. If it is a variable impedance element such as a diode, any element can achieve the same function. The number and position of the first variable passive element 64 and the second variable passive element 65 can also be appropriately designed by a person skilled in the art. In addition, the element itself does not need to be variable. For example, a plurality of elements with fixed impedance values ​​can be configured, and the impedance can be made variable by switching the combination of fixed value elements using a switching circuit. In addition, the circuit structures of these first variable passive elements 64 and the second variable passive element 65 can be appropriately designed by a person skilled in the art, respectively.

[0149] The relationship between the impedance of the first variable passive element 64 and the impedance of the second variable passive element 65 and LF Vpp is Figure 6 The relationship between the impedance of the second RF filter 63 shown and the LF Vpp is the same. That is, when the impedance of the variable passive elements 64 and 65 is increased, the LF Vpp is reduced. By adjusting the impedance of at least one of the first variable passive element 64 and the second variable passive element 65, the LF Vpp can be controlled. In addition, depending on the circuit design of the variable passive elements 64 and 65 and the measurement position of the LF Vpp, the LF Vpp may be reduced when the impedance of the variable passive elements 64 and 65 is reduced. The impedance can be adjusted according to the circuit design of the variable passive elements 64 and 65 and the measurement position of the LF Vpp.

[0150] Here, LF Vpp may vary due to reasons other than the variation of the DC voltage described above. For example, when an electromagnet is provided on the upper surface of the plasma processing chamber 10 and a magnetic field is formed in the processing space 10s, LF Vpp may vary due to the magnetic field. Therefore, when such LF Vpp varies due to a secondary factor, the impedance of at least one of the variable passive elements 64 and 65 can be adjusted as in the present embodiment, thereby controlling LF Vpp to be constant or within an allowable range.

[0151] In addition, for example, there may be an arbitrary control target value of LF Vpp, and the adjustment function related to the process such as RF power cannot be changed. For example, when the RF power is adjusted, it may affect the heating of the wafer and the process performance, so it is difficult to change the RF power. In this case, by adjusting the impedance of at least one of the variable passive elements 64 and 65 as in the present embodiment, the LF Vpp can be controlled to the control target value.

[0152] Furthermore, since LF Vpp can be controlled by adjusting the impedance of at least one of the variable passive elements 64 and 65, it is possible to adjust the voltage of the edge ring 14 to which the variable passive elements 64 and 65 are connected. As a result, the consumption of the edge ring 14 can be controlled by voltage.

[0153] In addition, in this embodiment, the impedance of at least one of the variable passive elements 64 and 65 is adjusted to control the LFVpp, but the tilt angle can also be controlled. The control method of controlling the tilt angle by adjusting the impedance of the variable passive elements 64 and 65 is the same as the control method of controlling the tilt angle by adjusting the impedance of the second RF filter 63 described above.

[0154] In addition, in the present embodiment, the variable passive elements 64 and 65 control the LF Vpp by adjusting the impedance, but may also be configured to be able to control the HF Vpp. Here, the HF Vpp may vary due to various reasons. For example, when a pulse power supply configured to be able to apply a pulse voltage other than the bias RF power LF to the lower electrode 12 is used instead of the bias RF power supply 51, the HF Vpp is likely to vary. In this case, by adjusting the impedance of at least one of the variable passive elements 64 and 65, the HF Vpp can be controlled to be constant or within an allowable range.

[0155] In addition, in this embodiment, the edge ring 14 and the variable passive elements 64 and 65 can be electrically connected. For example, the edge ring 14 and the variable passive elements 64 and 65 can be connected by non-contact or capacitive coupling. Or, for example, Fig.14 As shown, the edge ring 14 and the variable passive elements 64 and 65 can be directly electrically connected through the connecting portion 200. The structure of the connecting portion 200 is similar to Fig.11 The structure of the connecting portion 200 shown is the same. In addition, when the edge ring 14 is directly electrically connected to the variable passive elements 64 and 65, even if the frequency of the bias RF power LF is low, the controllability of the LF Vpp can be maintained.

[0156] In addition, in this embodiment, the variable passive elements 64 and 65 are electrically connected to the edge ring 14, but the connection destination of the variable passive elements 64 and 65 is not limited thereto. For example, the variable passive elements 64 and 65 may be electrically connected to the lower electrode 12, the conductive member constituting the lower electrode 12, the transmission path of the RF power, the circuit in the matching device 52, the pulse power supply used instead of the generating source RF power supply 50 or the bias RF power supply 51, and the like.

[0157] In addition, in the present embodiment, two variable passive elements 64 and 65 are provided, but the number of variable passive elements is not limited thereto. For example, only one of the variable passive elements 64 and 65 may be provided. In the case where the second variable passive element 65 is omitted, the first variable passive element 64 is connected to the ground potential. In addition, in the case where the first variable passive element 64 is omitted, the second variable passive element 65 is connected to the ground potential. In this case, the impedance of the second variable passive element 65 is configured to be variable. However, the function and circuit that the first variable passive element 64 has when the impedance is fixed can be integrated into the second variable passive element 65.

[0158] <Other embodiments>

[0159] In the above embodiment, LF Vpp is controlled by adjusting the impedance of the second RF filter 63, and LF Vpp or HF Vpp is controlled by adjusting the impedance of at least one of the variable passive elements 64 and 65, but the control object is not limited to Vpp. For example, electric power or current may be controlled as the control object.

[0160] <Other embodiments>

[0161] The etching device 1 of the above embodiment is a capacitive coupling type etching device, but the etching device to which the present invention is applied is not limited thereto. For example, the etching device may also be an inductive coupling type etching device.

[0162] The embodiments disclosed this time are illustrative and non-restrictive in all aspects. The above embodiments can be omitted, replaced, and changed in various forms without departing from the scope and purpose of the present invention. For example, the constituent elements of the above embodiments can be combined arbitrarily. From this arbitrary combination, the effects and effects of each constituent element in the combination can naturally be obtained, and other effects and effects that can be clearly understood by those skilled in the art from the description of this specification can be obtained.

[0163] In addition, the effects described in this specification are only illustrative or exemplary, and are not restrictive. That is, the technology of the present invention can achieve other effects that can be clearly understood by those skilled in the art based on the description of this specification in addition to or instead of the above effects.

[0164] In addition, the following configuration examples also belong to the technical scope of the present invention.

[0165] (1) A plasma processing device comprising:

[0166] a plasma processing chamber;

[0167] a substrate support disposed in the plasma processing chamber, the substrate support comprising a lower electrode, an electrostatic chuck, and an edge ring disposed in a manner to surround a substrate placed on the electrostatic chuck;

[0168] an upper electrode disposed above the substrate support;

[0169] a generation source RF power supply configured to supply generation source RF electric power to the upper electrode or the lower electrode to generate plasma from the gas in the plasma processing chamber;

[0170] a bias power supply configured to supply bias electric power to the lower electrode;

[0171] a DC power supply configured to apply a negative DC voltage to the edge ring;

[0172] an RF filter including at least one variable passive element electrically connected between the edge ring and the DC power source; and

[0173] The control unit is configured to control the DC power supply and the variable passive element to control the incident angle of ions in the plasma relative to the edge area of ​​the substrate carried on the electrostatic chuck, and to control the voltage of the bias power within an allowable range.

[0174] (2) The plasma processing apparatus according to (1) above, wherein:

[0175] comprising at least one conductor in contact with said edge ring,

[0176] The DC power supply is configured to apply a negative DC voltage to the edge ring via the at least one conductor.

[0177] The RF filter is electrically connected between the at least one conductor and the DC power source.

[0178] (3) The plasma processing apparatus according to (1) or (2) above, wherein:

[0179] The control unit simultaneously adjusts the DC voltage of the DC power supply and the impedance of the variable passive element.

[0180] (4) A plasma processing apparatus according to (1) or (2), wherein:

[0181] The control unit independently adjusts the DC voltage of the DC power supply and the impedance of the variable passive element.

[0182] (5) A plasma processing apparatus according to any one of (1) to (4) above, wherein:

[0183] The control unit adjusts the DC voltage of the DC power supply to control the incident angle of the ions.

[0184] (6) A plasma processing apparatus according to any one of (1) to (5), wherein:

[0185] The control unit adjusts the increase or decrease of the impedance of the variable passive element to control the voltage of the bias power within an allowable range.

[0186] (7) A plasma processing apparatus according to any one of (1) to (6), wherein:

[0187] comprising a sensor for measuring the voltage of the bias power or information associated with the voltage of the bias power,

[0188] The control unit controls the variable passive element based on a measurement result of the sensor.

[0189] (8) A plasma processing apparatus comprising:

[0190] a plasma processing chamber;

[0191] a substrate support disposed in the plasma processing chamber, the substrate support comprising an electrostatic chuck and an edge ring disposed in a manner to surround a substrate placed on the electrostatic chuck;

[0192] an RF power supply configured to generate RF electric power to generate plasma from the gas in the plasma processing chamber;

[0193] at least one variable passive element; and

[0194] The control unit is configured to control the variable passive element to control the voltage of the RF power.

[0195] (9) The plasma processing apparatus according to (8) above, wherein:

[0196] The at least one variable passive element is electrically connected to the edge ring.

[0197] (10) A plasma processing apparatus according to (9) above, wherein:

[0198] comprising at least one conductor in contact with said edge ring,

[0199] The at least one variable passive element is electrically connected to the edge ring via the at least one conductor.

[0200] (11) An etching method using a plasma processing apparatus, wherein:

[0201] The plasma processing device comprises:

[0202] a plasma processing chamber;

[0203] a substrate support disposed in the plasma processing chamber, the substrate support comprising an electrostatic chuck and an edge ring disposed in a manner to surround a substrate placed on the electrostatic chuck;

[0204] an RF power supply configured to generate RF electric power to generate plasma from the gas in the plasma processing chamber; and

[0205] at least one variable passive element,

[0206] The etching method comprises:

[0207] (a) placing a substrate on the electrostatic chuck;

[0208] (b) generating plasma from the gas in the plasma processing chamber using the RF power;

[0209] (c) a step of etching the substrate using the generated plasma; and

[0210] (d) A step of controlling the variable passive element to control the voltage of the RF power.

[0211] Description of the accompanying drawings

[0212] 1 Etching device

[0213] 10 plasma processing chamber 11 workbench

[0214] 12 Lower electrode

[0215] 13 Electrostatic chuck

[0216] 14 Edge Ring

[0217] 21 electrode plate

[0218] 50 Generator RF Power

[0219] 51 Bias RF power supply

[0220] 60 DC power supply

[0221] 62 First RF Filter

[0222] 63 Second RF filter

[0223] 100 Control Department

[0224] W chip.

Claims

1. A plasma processing device, characterized in that: include: a plasma processing chamber; a substrate support disposed in the plasma processing chamber, the substrate support comprising a lower electrode, an electrostatic chuck, and an edge ring disposed in a manner to surround a substrate placed on the electrostatic chuck; an upper electrode disposed above the substrate support; a generation source RF power supply configured to supply generation source RF electric power to the upper electrode or the lower electrode to generate plasma from the gas in the plasma processing chamber; a bias power supply configured to supply bias electric power to the lower electrode; a DC power supply configured to apply a negative-polarity DC voltage to the edge ring; an RF filter including at least one variable passive element electrically connected between the edge ring and the DC power source; and A control unit is configured to control the DC power supply and the variable passive element to control the incident angle of ions in the plasma relative to the edge area of ​​the substrate carried on the electrostatic chuck and to control the voltage of the bias power within an allowable range.

2. The plasma processing device according to claim 1, characterized in that: comprising at least one conductor in contact with said edge ring, The DC power supply is configured to apply a negative DC voltage to the edge ring via the at least one conductor. The RF filter is electrically connected between the at least one conductor and the DC power source.

3. The plasma processing device according to claim 1 or 2, characterized in that: The control unit simultaneously adjusts the DC voltage of the DC power supply and the impedance of the variable passive element.

4. The plasma processing device according to claim 1 or 2, characterized in that: The control unit independently adjusts the DC voltage of the DC power supply and the impedance of the variable passive element.

5. The plasma processing device according to claim 1 or 2, characterized in that: The control unit adjusts the DC voltage of the DC power supply to control the incident angle of the ions.

6. The plasma processing device according to claim 1 or 2, characterized in that: The control unit adjusts the increase or decrease of the impedance of the variable passive element to control the voltage of the bias power within an allowable range.

7. The plasma processing device according to claim 1 or 2, characterized in that: include: a sensor for measuring the voltage of the bias electric power or information associated with the voltage of the bias electric power, The control section controls the variable passive element based on a measurement result of the sensor.

8. A plasma processing device, characterized in that: include: a plasma processing chamber; a substrate support disposed in the plasma processing chamber, the substrate support comprising an electrostatic chuck and an edge ring disposed in a manner to surround a substrate placed on the electrostatic chuck; an RF power supply configured to generate RF electrical power to generate plasma from a gas within the plasma processing chamber; at least one variable passive element; and The control unit is configured to control the variable passive element to control the voltage of the RF power.

9. The plasma processing device according to claim 8, characterized in that: The at least one variable passive element is electrically connected to the edge ring.

10. The plasma processing device according to claim 9, characterized in that: comprising at least one conductor in contact with said edge ring, The at least one variable passive element is electrically connected to the edge ring via the at least one conductor.

11. An etching method, characterized in that: The etching method is an etching method using a plasma processing device, The plasma processing device comprises: a plasma processing chamber; a substrate support disposed in the plasma processing chamber, the substrate support comprising an electrostatic chuck and an edge ring disposed in a manner to surround a substrate placed on the electrostatic chuck; an RF power supply configured to generate RF electrical power to generate plasma from a gas within the plasma processing chamber; and at least one variable passive element, The etching method comprises: (a) placing a substrate on the electrostatic chuck; (b) generating plasma from the gas in the plasma processing chamber using the RF electric power; (c) a step of etching the substrate using the generated plasma; and (d) A step of controlling the variable passive element to control the voltage of the RF electric power.

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