JP7645694B2 - Plasma Processing Equipment - Google Patents

Description

An exemplary embodiment of the present disclosure relates to a plasma processing apparatus.

A plasma processing apparatus is used for plasma processing of a substrate. The plasma processing apparatus includes a chamber, an electrostatic chuck, and a lower electrode. The electrostatic chuck and the lower electrode are provided in the chamber. The electrostatic chuck is provided on the lower electrode. The electrostatic chuck supports an edge ring placed thereon. The edge ring is sometimes called a focus ring. The electrostatic chuck supports a substrate placed within an area surrounded by the edge ring. When plasma processing is performed in the plasma processing apparatus, a gas is supplied into the chamber. Also, high frequency power is supplied to the lower electrode. A plasma is formed from the gas in the chamber. The substrate is processed by chemical species such as ions and radicals from the plasma.

When plasma processing is performed, the edge ring is worn and the thickness of the edge ring decreases. When the thickness of the edge ring decreases, the position of the upper end of the plasma sheath (hereinafter referred to as the "sheath") above the edge ring becomes lower. The vertical position of the upper end of the sheath above the edge ring and the vertical position of the upper end of the sheath above the substrate should be equal. Japanese Patent Application Laid-Open No. 2008-227063 (hereinafter referred to as "Patent Document 1") discloses a plasma processing apparatus that makes it possible to adjust the vertical position of the upper end of the sheath above the edge ring. The plasma processing apparatus described in Patent Document 1 is configured to apply a DC voltage to the edge ring. In addition, the plasma processing apparatus described in Patent Document 1 is configured to adjust the power level of the high-frequency power supplied to the lower electrode when a DC voltage is applied to the edge ring.

JP 2008-227063 A

This disclosure provides a technique that allows for adjustment of the sheath thickness on the edge ring and the radial distribution of plasma density.

In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a radio frequency power supply, and a bias power supply. The substrate support has a bias electrode. The radio frequency power supply generates radio frequency power that is supplied to the radio frequency electrode to generate a plasma above a substrate supported by the substrate support in the chamber. The bias power supply is connected to the bias electrode through an electrical path. An edge ring is mounted on the substrate support. The edge ring is electrically connected to the bias power supply through an impedance adjuster that provides a variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or is electrically connected to a separate bias power supply. An outer ring extends radially outward relative to the edge ring. The outer ring is electrically connected to the radio frequency power supply to receive a portion of the radio frequency power, or is electrically connected to a separate radio frequency power supply to receive a separate radio frequency power.

According to one exemplary embodiment, it is possible to adjust the thickness of the sheath on the edge ring and adjust the radial distribution of plasma density.

1 is a schematic diagram of a plasma processing apparatus according to an exemplary embodiment; FIG. 13 is a schematic diagram of a plasma processing apparatus according to another exemplary embodiment. FIG. 13 is a schematic diagram of a plasma processing apparatus according to yet another exemplary embodiment. FIG. 13 is a schematic diagram of a plasma processing apparatus according to yet another exemplary embodiment.

Various exemplary embodiments are described below.

In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a radio frequency power supply, and a bias power supply. The substrate support has a bias electrode. The radio frequency power supply generates radio frequency power that is supplied to the radio frequency electrode to generate a plasma above a substrate supported by the substrate support in the chamber. The bias power supply is connected to the bias electrode through an electrical path. An edge ring is mounted on the substrate support. The edge ring is electrically connected to the bias power supply through an impedance adjuster that provides a variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring, or is electrically connected to a separate bias power supply. An outer ring extends radially outward relative to the edge ring. The outer ring is electrically connected to the radio frequency power supply to receive a portion of the radio frequency power, or is electrically connected to a separate radio frequency power supply to receive a separate radio frequency power.

According to the above embodiment, the level of the negative bias in the edge ring is adjusted by an impedance adjuster or another bias power supply. Therefore, according to the above embodiment, it is possible to adjust the thickness of the sheath on the edge ring. Also, in the above embodiment, a part of the high frequency power or another high frequency power is supplied to the outer ring. Therefore, according to the above embodiment, the plasma density is adjusted even above the outer ring. Therefore, according to the above embodiment, it is possible to adjust the radial distribution of plasma density in a space that also includes the area outside the area on the edge ring.

In one exemplary embodiment, the plasma processing apparatus may further include a first electrode and a second electrode. The first electrode is electrically coupled to the edge ring. The first electrode may be capacitively coupled to the edge ring. The second electrode is electrically coupled to the outer ring. The second electrode may be capacitively coupled to the outer ring. The impedance adjuster provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode. The outer ring receives a portion of the RF power or another RF power from another RF power source via the second electrode.

In one exemplary embodiment, the substrate support may include a base and an electrostatic chuck disposed on the base.

In one exemplary embodiment, the base may provide a lower electrode that is a bias electrode. The lower electrode may be the radio frequency electrode described above. In this embodiment, the radio frequency power source may be electrically connected to the lower electrode via the electrical path described above.

In one exemplary embodiment, the plasma processing apparatus may further include an impedance adjuster that provides a variable impedance between the electrical path and the outer ring or between the lower electrode and the outer ring.

In one exemplary embodiment, the plasma processing apparatus may further include a filter connected between the impedance adjuster and the second electrode to provide a variable impedance between the electrical path and the outer ring or between the lower electrode and the outer ring. The filter may have a frequency characteristic that selectively passes high frequency power with respect to the electrical bias supplied from the bias power supply to the lower electrode.

In one exemplary embodiment, the bias electrode may be disposed within the electrostatic chuck. The base may provide a lower electrode that is a radio frequency electrode. A radio frequency power source may be electrically connected to the lower electrode.

In one exemplary embodiment, the plasma processing apparatus may further include an impedance adjuster. The impedance adjuster provides a variable impedance between the electrical path connecting the RF power source to the lower electrode and the outer ring or between the lower electrode and the outer ring.

In one exemplary embodiment, the outer ring may extend around the edge ring.

In one exemplary embodiment, the bias power supply may be configured to provide radio frequency bias power to the bias electrode or to periodically apply a pulsed voltage or a voltage having any waveform to the bias electrode. The pulsed voltage may have a negative polarity. The pulsed voltage may be a pulsed negative polarity DC voltage.

Various exemplary embodiments will be described in detail below with reference to the drawings. Note that the same or equivalent parts in each drawing will be given the same reference numerals.

Figure 1 is a schematic diagram of a plasma processing apparatus according to an exemplary embodiment. The plasma processing apparatus 1 shown in Figure 1 is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a chamber 10. The chamber 10 provides an internal space 10s therein. The central axis of the internal space 10s is an axis AX extending in the vertical direction.

In one embodiment, the chamber 10 may include a chamber body 12. The chamber body 12 has a generally cylindrical shape. The internal space 10s is provided within the chamber body 12. The chamber body 12 is made of, for example, aluminum. The chamber body 12 is electrically grounded. A plasma-resistant film is formed on the inner wall surface of the chamber body 12, i.e., the wall surface defining the internal space 10s. This film may be a ceramic film, such as a film formed by anodization or a film formed from yttrium oxide.

The sidewall of the chamber body 12 provides a passage 12p. The substrate W passes through the passage 12p when being transported between the internal space 10s and the outside of the chamber 10. A gate valve 12g is provided along the sidewall of the chamber body 12 to open and close this passage 12p.

The plasma processing apparatus 1 further includes a substrate support 16. The substrate support 16 is configured to support a substrate W placed thereon in the chamber 10. The substrate W has a substantially disk shape. The substrate W is placed on the substrate support 16 so that its center is located on the axis AX. The substrate support 16 is further configured to support an edge ring ER. The edge ring ER has a ring shape. The edge ring ER may be conductive. The edge ring ER is formed of, for example, silicon or silicon carbide. The edge ring ER is placed on the substrate support 16 so that its central axis coincides with the axis AX. The substrate W is disposed on the substrate support 16 and within a region surrounded by the edge ring ER.

The substrate support 16 may be surrounded by an insulating portion 17. The insulating portion 17 extends circumferentially outside the substrate support 16 in a radial direction relative to the axis AX. The insulating portion 17 is formed from an insulating material such as quartz. The insulating portion 17 may support the substrate support 16.

The substrate support 16 has a base 18. The substrate support 16 may further have an electrostatic chuck 20. The base 18 and the electrostatic chuck 20 are provided in the chamber 10. The base 18 is made of a conductive material such as aluminum, and has a generally disk-like shape. The central axis of the base 18 is the axis AX.

The base 18 provides a flow path 18f therein. The flow path 18f is a flow path for a heat exchange medium. The heat exchange medium is, for example, a refrigerant. The flow path 18f is connected to a supply device 22 for the heat exchange medium. The supply device 22 is provided outside the chamber 10. The flow path 18f receives the heat exchange medium supplied from the supply device 22. The heat exchange medium supplied to the flow path 18f is returned to the supply device 22.

The electrostatic chuck 20 is provided on the base 18. When the substrate W is processed in the internal space 10s, it is placed on the electrostatic chuck 20 and held by the electrostatic chuck 20.

The electrostatic chuck 20 has a body and a chuck electrode. The body of the electrostatic chuck 20 is formed from a dielectric material such as aluminum oxide or aluminum nitride. The body of the electrostatic chuck 20 has an approximately disk shape. The central axis of the electrostatic chuck 20 is the axis AX. The chuck electrode is provided within the body of the electrostatic chuck 20. The chuck electrode has a film shape. The chuck electrode is electrically connected to a DC power supply via a switch. When a voltage from the DC power supply is applied to the chuck electrode, an electrostatic attractive force is generated between the electrostatic chuck 20 and the substrate W. The generated electrostatic attractive force attracts the substrate W to the electrostatic chuck 20 and the substrate W is held by the electrostatic chuck 20.

The electrostatic chuck 20 includes a substrate mounting area. The substrate mounting area is a region having a substantially disk shape. The central axis of the substrate mounting area is axis AX. When the substrate W is processed in the chamber 10, it is placed on the upper surface of the substrate mounting area.

In one embodiment, the electrostatic chuck 20 may further include an edge ring mounting region. The edge ring mounting region extends circumferentially around the central axis of the electrostatic chuck 20 to surround the substrate mounting region. An edge ring ER is mounted on an upper surface of the edge ring mounting region. The edge ring ER may be partially mounted on the insulating portion 17.

The plasma processing apparatus 1 may be provided with a gas supply line 24. The gas supply line 24 supplies a heat transfer gas, such as He gas, from a gas supply mechanism to the gap between the upper surface of the electrostatic chuck 20 and the rear surface (lower surface) of the substrate W.

The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 16. The upper electrode 30 closes the upper opening of the chamber body 12 together with a member 32. The member 32 has insulating properties. The upper electrode 30 is supported on the upper part of the chamber body 12 via the member 32.

The upper electrode 30 may include a top plate 34 and a support 36. The bottom surface of the top plate 34 defines the internal space 10s. The top plate 34 provides a plurality of gas discharge holes 34a. Each of the plurality of gas discharge holes 34a penetrates the top plate 34 in the thickness direction (vertical direction). The top plate 34 is formed of, for example, silicon. Alternatively, the top plate 34 may have a structure in which a plasma-resistant film is provided on the surface of an aluminum member. This film may be a ceramic film, such as a film formed by anodizing or a film formed of yttrium oxide.

The support 36 detachably supports the top plate 34. The support 36 is made of a conductive material such as aluminum. The support 36 provides a gas diffusion chamber 36a therein. The support 36 further provides a plurality of gas holes 36b. The plurality of gas holes 36b extend downward from the gas diffusion chamber 36a and are respectively connected to the plurality of gas discharge holes 34a. The support 36 further provides a gas introduction port 36c. The gas introduction port 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas introduction port 36c.

The gas source group 40 is connected to the gas supply pipe 38 via the valve group 41, the flow rate controller group 42, and the valve group 43. The gas source group 40, the valve group 41, the flow rate controller group 42, and the valve group 43 constitute a gas supply unit. The gas source group 40 includes a plurality of gas sources. Each of the valve group 41 and the valve group 43 includes a plurality of valves (e.g., opening and closing valves). The flow rate controller group 42 includes a plurality of flow rate controllers. Each of the plurality of flow rate controllers of the flow rate controller group 42 is a mass flow controller or a pressure-controlled flow rate controller. Each of the plurality of gas sources of the gas source group 40 is connected to the gas supply pipe 38 via a corresponding valve of the valve group 41, a corresponding flow rate controller of the flow rate controller group 42, and a corresponding valve of the valve group 43. The plasma processing apparatus 1 is capable of supplying gas from one or more gas sources selected from the plurality of gas sources of the gas source group 40 to the internal space 10s at individually adjusted flow rates.

The plasma processing apparatus 1 may further include a baffle member 48. The baffle member 48 extends between the insulating portion 17 and the side wall of the chamber body 12. The baffle member 48 may be constructed, for example, by coating an aluminum member with a ceramic such as yttrium oxide. The baffle member 48 provides a plurality of through holes. The space above the baffle member 48 and the space below the baffle member 48 are connected via the plurality of through holes in the baffle member 48.

The plasma processing apparatus 1 may further include an exhaust device 50. The exhaust device 50 is connected to the bottom of the chamber body 12 below the baffle member 48 via an exhaust pipe 52. The exhaust device 50 has a pressure controller such as an automatic pressure control valve and a vacuum pump such as a turbomolecular pump, and can reduce the pressure in the internal space 10s.

The plasma processing apparatus 1 further includes a high-frequency power supply 61. The high-frequency power supply 61 generates high-frequency power HF that is supplied to a high-frequency electrode to generate plasma above the substrate W supported by the substrate support 16. The high-frequency power HF has a frequency in the range of 27 to 100 MHz, for example, a frequency of 40 MHz or 60 MHz. In one embodiment, the high-frequency electrode is the base 18. That is, in one embodiment, the base 18 provides a lower electrode that is a high-frequency electrode. The high-frequency power supply 61 is connected to the base 18 via a matching device 63. The matching device 63 has a matching circuit configured to match the impedance of the load side (base 18 side) of the high-frequency power supply 61 to the output impedance of the high-frequency power supply 61. In one embodiment, the high-frequency power supply 61 may be connected to the base 18 via the matching device 63 and an electrical path 71. In one embodiment, the electrical path 71 connects the bias power supply 62 to the base 18. That is, in one embodiment, the base 18 provides a lower electrode that is a bias electrode.

The bias power supply 62 is configured to provide an electrical bias BE to a bias electrode of the substrate support 16 (base 18 in the example of FIG. 1). The electrical bias BE can be used to attract ions to the substrate W.

In one embodiment, the bias power supply 62 may generate high frequency bias power as the electrical bias BE. The frequency of the high frequency bias power is different from the frequency of the high frequency power HF. The frequency of the high frequency bias power may be lower than the frequency of the high frequency power HF. The frequency of the high frequency bias power is in the range of 50 kHz to 27 MHz, for example, 400 kHz. Note that when the high frequency power supply 61 is connected to the upper electrode 30 instead of the base 18, the frequency of the high frequency bias power generated by the bias power supply 62 may be lower or higher than the frequency of the high frequency power HF, or may be the same as the frequency of the high frequency power HF.

The bias power supply 62 is connected to the bias electrode (the base 18 in the example of FIG. 1) via a matching device 64 in order to supply high-frequency bias power to the bias electrode. The matching device 64 has a matching circuit configured to match the impedance of the load side of the bias power supply 62 to the output impedance of the bias power supply 62.

The high frequency bias power may be continuously supplied to the base 18. Alternatively, the high frequency bias power may be intermittently and periodically supplied to the base 18.

In another embodiment, the bias power supply 62 may be configured to apply a pulsed voltage or a voltage having an arbitrary waveform as the electrical bias BE to the bias electrode (base 18 in the example of FIG. 1). The pulsed voltage may have a negative polarity. The pulsed voltage may be a pulsed negative DC voltage. The pulsed voltage may be applied to the base 18 periodically. The level of the pulsed voltage may change during the period in which the pulsed voltage is applied to the bias electrode.

In one embodiment, the plasma processing apparatus 1 may further include a first electrode 81. The first electrode 81 is electrically coupled to the edge ring ER. The first electrode 81 may be capacitively coupled to the edge ring ER. The first electrode 81 is disposed below the edge ring ER. In one embodiment, the first electrode 81 may be provided in the edge ring mounting area of the electrostatic chuck 20. In another embodiment, the first electrode 81 may be provided in the insulating portion 17. The first electrode 81 may be directly coupled to the edge ring ER. The first electrode 81 may be a single electrode or may extend in the circumferential direction around the axis AX. Alternatively, the first electrode 81 may include a plurality of electrodes arranged in the circumferential direction around the axis AX. The plurality of electrodes constituting the first electrode 81 may be arranged at equal intervals.

In one embodiment, the plasma processing apparatus 1 may further include an impedance adjuster 83. The impedance adjuster 83 provides a variable impedance. The variable impedance of the impedance adjuster 83 may be controlled by a controller MC described later. The impedance adjuster 83 is connected between the high-frequency electrode and the edge ring ER. In one embodiment, the impedance adjuster 83 is connected between the high-frequency electrode (the base 18 in the example of FIG. 1) and the first electrode 81. In one embodiment, the impedance adjuster 83 includes one or more variable impedance elements. The one or more variable impedance elements may include a variable capacitance capacitor. In another embodiment, the impedance adjuster 83 may include a circuit configured from a parallel connection of multiple series circuits. Each of the multiple series circuits may include a series connection of a fixed impedance element and a switching element. The fixed impedance element is, for example, a fixed capacitance capacitor.

In one embodiment, the plasma processing apparatus 1 may further include a second electrode 82. The second electrode 82 is electrically coupled to the outer ring OR. The second electrode 82 may be capacitively coupled to the outer ring OR. The outer ring OR has a ring shape. The outer ring OR may be conductive. The outer ring OR is formed of, for example, silicon or silicon carbide. The outer ring OR extends radially outward relative to the edge ring ER. The outer ring OR is disposed such that its central axis coincides with the axis AX. In one embodiment, the outer ring OR extends to surround the edge ring ER. The outer ring OR may be placed on the substrate support 16 or on the insulating portion 17.

The second electrode 82 may be disposed below the outer ring OR as shown in FIG. 1. The second electrode 82 may be provided in or on the surface of the insulating portion 17. The second electrode 82 may be directly coupled to the outer ring OR. The second electrode 82 may be a single electrode, and may extend in a circumferential direction around the axis AX. Alternatively, the second electrode 82 may include a plurality of electrodes arranged in a circumferential direction around the axis AX. The plurality of electrodes constituting the second electrode 82 may be arranged at equal intervals.

In the plasma processing apparatus 1, a portion of the high frequency power HF is supplied to the outer ring OR. In one embodiment, a portion of the high frequency power HF is supplied to the outer ring OR through the second electrode 82. The outer ring OR is connected to the electrical path 71 through the impedance adjuster 84. In one embodiment, the second electrode 82 is connected to the electrical path 71 through the impedance adjuster 84. That is, the impedance adjuster 84 is connected between the electrical path 71 and the second electrode 82. The impedance adjuster 84 provides a variable impedance. The variable impedance of the impedance adjuster 84 can be controlled by the control unit MC. In one embodiment, the impedance adjuster 84 includes one or more variable impedance elements. The one or more impedance elements may include a variable capacitance capacitor. In another embodiment, the impedance adjuster 84 may include a circuit configured from a parallel connection of a plurality of series circuits. Each of the plurality of series circuits may include a series connection of a fixed impedance element and a switching element. The fixed impedance element is, for example, a fixed capacitance capacitor.

In one embodiment, the plasma processing apparatus 1 may further include a control unit MC. The control unit MC is a computer equipped with a processor, a storage device, an input device, a display device, etc., and controls each part of the plasma processing apparatus 1. Specifically, the control unit MC executes a control program stored in the storage device, and controls each part of the plasma processing apparatus 1 based on recipe data stored in the storage device. Under the control of the control unit MC, a process specified by the recipe data is executed in the plasma processing apparatus 1.

The control unit MC may be configured to control the impedance adjuster 83 and the impedance adjuster 84 to set the impedance of the impedance adjuster 83 and the impedance of the impedance adjuster 84.

The plasma processing apparatus 1 may further include one or more sensors. The one or more sensors may include a sensor that measures the distribution of plasma density in the internal space 10s. The one or more sensors may include a sensor that measures the voltage of each of the substrate W, the edge ring ER, and the outer ring OR. The one or more sensors may include a sensor that measures the current flowing through each of the substrate W, the edge ring ER, and the outer ring OR. The one or more sensors may include a sensor that measures the emission intensity distribution in the internal space 10s. The control unit MC may control the impedance adjuster 83 and the impedance adjuster 84 to set their impedances according to one or more measured values obtained by measurement with one or more sensors.

Alternatively, the control unit MC may control the impedance adjuster 83 and the impedance adjuster 84 to set their impedances using data that is preset according to the tendency of the process executed according to the recipe data. Alternatively, the control unit MC may control the impedance adjuster 83 and the impedance adjuster 84 to set their impedances using data according to the execution time length of the process executed according to the recipe data. Alternatively, the control unit MC may control the impedance adjuster 83 and the impedance adjuster 84 to set their impedances using data according to the wear prediction of the edge ring ER and the outer ring OR.

When plasma processing is performed in the plasma processing apparatus 1, gas is supplied to the internal space 10s. Then, high-frequency power HF and/or an electrical bias BE is supplied, exciting the gas in the internal space 10s. As a result, plasma is generated in the internal space 10s. The substrate W is processed by chemical species such as ions and radicals from the generated plasma. For example, the substrate is etched by the chemical species from the plasma.

In the plasma processing apparatus 1, the distribution ratio of the electric bias BE between the bias electrode (base 18 in the example of FIG. 1) and the edge ring ER is adjusted by the impedance adjuster 83. Therefore, the level of the negative bias in the edge ring ER is adjusted by the impedance adjuster 83. Therefore, according to the plasma processing apparatus 1, it is possible to adjust the thickness of the sheath on the edge ring ER.

In addition, in the plasma processing apparatus 1, a portion of the high frequency power HF is supplied to the outer ring OR. The distribution ratio of the high frequency power HF between the high frequency electrode (base 18 in the example of FIG. 1) and the outer ring OR is adjusted by the impedance adjuster 84. Therefore, according to the plasma processing apparatus 1, the plasma density is adjusted even above the outer ring OR. Therefore, according to the plasma processing apparatus 1, it is possible to adjust the radial distribution of plasma density in a space that also includes the area outside the area on the edge ring ER.

In one embodiment, the electrical path 71 may be configured to distribute power to the base 18 uniformly in the circumferential direction about the axis AX. In one embodiment, the electrical path 71 may include multiple branch lines that are respectively connected to multiple positions on the base 18. The multiple positions have equal distances from the axis AX and are arranged at equal intervals in the circumferential direction about the axis AX. In addition, the multiple branch lines of the electrical path 71 are arranged at equal intervals in the circumferential direction about the axis AX. In addition, the electrical lengths of the electrical path 71 for each of the multiple positions on the base 18 are approximately equal to each other. According to this embodiment, it is possible to supply power uniformly to the base 18 via the electrical path 71.

In one embodiment, the plasma processing apparatus 1 may further include an electrical path 72. The electrical path 72 is an electrical path for power distributed between the bias electrode (base 18 in the example of FIG. 1) and the edge ring ER (or the first electrode 81) and supplied to the edge ring ER. The electrical path 72 may include a plurality of branch lines respectively connected to a plurality of positions of the edge ring ER (or the first electrode 81). The plurality of positions have an equal distance from the axis line AX and are arranged at equal intervals in the circumferential direction about the axis line AX. In addition, the plurality of branch lines of the electrical path 72 are arranged at equal intervals in the circumferential direction about the axis line AX. In addition, the electrical lengths of the electrical path 72 for each of the plurality of positions of the edge ring ER (or the first electrode 81) are approximately equal to each other. According to this embodiment, it is possible to uniformly supply power to the edge ring ER via the electrical path 72.

In one embodiment, the plasma processing apparatus 1 may further include an electrical path 73. The electrical path 73 is an electrical path for power distributed between the high-frequency electrode (base 18 in the example of FIG. 1) and the outer ring OR (or second electrode 82) and supplied to the outer ring OR. The electrical path 73 may include a plurality of branch lines respectively connected to a plurality of positions on the outer ring OR (or second electrode 82). The plurality of positions have equal distances from the axis AX and are arranged at equal intervals in the circumferential direction about the axis AX. In addition, the plurality of branch lines of the electrical path 73 are arranged at equal intervals in the circumferential direction about the axis AX. In addition, the electrical lengths of the electrical path 73 for each of the plurality of positions on the outer ring OR (or second electrode 82) are approximately equal to each other. According to this embodiment, it is possible to uniformly supply power to the outer ring OR via the electrical path 73.

In one embodiment, the plasma processing apparatus 1 may further include a filter 74. The filter 74 is connected between the impedance adjuster 84 and the outer ring OR (or the second electrode 82). The filter 74 may have a frequency characteristic that selectively passes the high frequency power HF relative to the electric bias BE. Alternatively, the filter 74 may have a frequency characteristic that selectively passes the electric bias BE relative to the high frequency power HF. Alternatively, the pass band of the filter 74 may be changeable to any of the band of the high frequency power HF, the band of the electric bias BE, or both bands.

Refer to FIG. 2 below. FIG. 2 is a schematic diagram of a plasma processing apparatus according to another exemplary embodiment. Below, the differences between the plasma processing apparatus 1B shown in FIG. 2 and the plasma processing apparatus 1 will be described.

The plasma processing apparatus 1B does not include an impedance adjuster 84. The plasma processing apparatus 1B further includes a high-frequency power supply 91. The high-frequency power supply 91 is configured to generate high-frequency power to be supplied to the outer ring OR. The frequency of the high-frequency power generated by the high-frequency power supply 91 may be the same as or different from the frequency of the high-frequency power HF.

The high frequency power supply 91 is connected to the outer ring OR via a matching device 93 and an electrical path 75. The high frequency power supply 91 may be connected to the second electrode 82 via a matching device 93 and an electrical path 75. The matching device 93 has a matching circuit configured to match the impedance of the load side of the high frequency power supply 91 to the output impedance of the high frequency power supply 91.

In one embodiment, the electrical path 75 may include multiple branch lines that are respectively connected to multiple positions on the outer ring OR (or the second electrode 82). The multiple positions have equal distances from the axis AX and are arranged at equal intervals in the circumferential direction about the axis AX. The multiple branch lines of the electrical path 75 are also arranged at equal intervals in the circumferential direction about the axis AX. The electrical lengths of the electrical path 75 for each of the multiple positions on the outer ring OR (or the second electrode 82) are approximately equal to each other. According to this embodiment, it is possible to uniformly supply power to the outer ring OR via the electrical path 75.

In the plasma processing apparatus 1B, the control unit MC may further control the high-frequency power source 91 to set the level of the high-frequency power generated by the high-frequency power source 91 in accordance with one or more measurement values obtained by measuring the plasma processing apparatus 1 using one or more of the sensors described above.

Alternatively, the control unit MC may further control the high frequency power supply 91 using data preset according to the tendency of the process executed according to the recipe data to set the level of high frequency power generated by the high frequency power supply 91. Alternatively, the control unit MC may further control the high frequency power supply 91 using data according to the execution time length of the process executed according to the recipe data to set the level of high frequency power generated by the high frequency power supply 91. Alternatively, the control unit MC may further control the high frequency power supply 91 using data according to the predicted wear of the edge ring ER and the outer ring OR to set the level of high frequency power generated by the high frequency power supply 91.

Refer to FIG. 3 below. FIG. 3 is a schematic diagram of a plasma processing apparatus according to yet another exemplary embodiment. Below, the differences between the plasma processing apparatus 1C and the plasma processing apparatus 1B shown in FIG. 3 will be described.

The plasma processing apparatus 1C does not include an impedance adjuster 83. In the plasma processing apparatus 1C, the bias power supply 92 is connected to the edge ring ER (or the first electrode 81) via a matching device 94 and an electrical path 72. The bias power supply 92 is a power supply similar to the bias power supply 62. The matching device 94 includes a matching circuit for matching the impedance of the load side of the bias power supply 92 to the output impedance of the bias power supply 92.

In the plasma processing apparatus 1C, the control unit MC may further control the bias power supply 92 to set the level of the electrical bias generated by the bias power supply 92 in response to one or more measurement values obtained by measuring the plasma processing apparatus 1 using one or more sensors described above.

Alternatively, the control unit MC may further control the bias power supply 92 using data preset according to the tendency of the process executed according to the recipe data to set the level of the electrical bias generated by the bias power supply 92. Alternatively, the control unit MC may further control the bias power supply 92 using data according to the execution time length of the process executed according to the recipe data to set the level of the electrical bias generated by the bias power supply 92. Alternatively, the control unit MC may further control the bias power supply 92 using data according to the predicted wear of the edge ring ER and the outer ring OR to set the level of the electrical bias generated by the bias power supply 92.

In addition, in the plasma processing apparatus 1C, a separate high-frequency power source that generates high-frequency power may be electrically connected to the edge ring ER (or the first electrode 81) via a matching device.

Refer to FIG. 4 below. FIG. 4 is a diagram that shows a schematic diagram of a plasma processing apparatus according to yet another exemplary embodiment. Below, the differences between the plasma processing apparatus 1D shown in FIG. 4 and the plasma processing apparatus 1C will be described. In the plasma processing apparatus 1D, a bias electrode 21 is provided in the electrostatic chuck 20. The bias electrode 21 may also serve as the chuck electrode, or may be an electrode separate from the chuck electrode. In the plasma processing apparatus 1D, the bias power supply 62 is connected to the bias electrode 21 via an electrical path separate from the electrical path 71.

Although various exemplary embodiments have been described above, various additions, omissions, substitutions, and modifications may be made without being limited to the exemplary embodiments described above. In addition, elements in different embodiments may be combined to form other embodiments.

For example, in another embodiment, the high frequency power supply 61 may be connected to the upper electrode 30 rather than the base 18 via a matching device 63. In this case, the upper electrode 30 is used as the high frequency electrode.

In yet another embodiment, when the high frequency power supply 61 is connected to the base 18 via the electrical path 71, the impedance adjuster 83 may be connected between the electrical path 71 and the edge ring ER (or the first electrode 81).

In yet another embodiment, the outer ring OR may be positioned at a higher position than the edge ring ER in the vertical direction. In yet another embodiment, the outer ring OR may be positioned to surround the upper electrode 30. In this case, the outer ring OR may be positioned within the member 32.

In yet another embodiment, the impedance adjuster 84 may be connected between the base 18 and the outer ring OR (or the second electrode 82).

In yet another embodiment, a separate bias power supply may be connected to the outer ring OR (or the second electrode 82) via electrical path 75. The separate bias power supply may generate radio frequency bias power supplied to the outer ring OR, or may periodically generate a pulsed voltage or a voltage having an arbitrary waveform that is applied to the outer ring OR.

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

1...plasma processing apparatus, 10...chamber, 16...substrate support, 18...base, 61...high frequency power supply, 62...bias power supply, ER...edge ring, 81...first electrode, 83...impedance adjuster, OR...outer ring, 82...second electrode.

Claims (6)

A chamber;
a substrate support having a bias electrode;
a radio frequency power supply that generates radio frequency power that is supplied to a radio frequency electrode to generate a plasma above a substrate supported by the substrate support within the chamber;
a bias power supply connected to the bias electrode via an electrical path;
Equipped with
an edge ring mounted on the substrate support is electrically connected to the bias power supply via an impedance adjuster that provides a variable impedance between the bias electrode and the edge ring or between the electrical path and the edge ring to adjust a thickness of a sheath on the edge ring, or is electrically connected to a separate bias power supply;
an outer ring extending radially outward from the edge ring is electrically connected to the high frequency power source to receive a portion of the high frequency power, or is electrically connected to another high frequency power source to receive another high frequency power, in order to adjust a distribution of plasma density in the radial direction;
the substrate support includes a base and an electrostatic chuck provided on the base;
the bias electrode is provided in the electrostatic chuck;
the base provides a lower electrode which is the high-frequency electrode;
The high frequency power source is electrically connected to the lower electrode.
Plasma processing equipment. a first electrode electrically coupled to the edge ring;
a second electrode electrically coupled to the outer ring;
Further comprising:
the impedance adjuster provides a variable impedance between the bias electrode and the first electrode or between the electrical path and the first electrode;
the outer ring receives a portion of the high frequency power or another high frequency power from another high frequency power source via the second electrode;
The plasma processing apparatus according to claim 1 . a second bias electrode disposed within the electrostatic chuck below the edge ring and electrically coupled to the edge ring;
The separate bias electrode is electrically connected to the bias power supply via the impedance adjuster or is electrically connected to the separate bias power supply.
The plasma processing apparatus according to claim 1 . The plasma processing apparatus according to any one of claims 1 to 3, further comprising an impedance adjuster that provides a variable impedance between an electrical path connecting the high frequency power supply to the lower electrode and the outer ring, or between the lower electrode and the outer ring. 5. The plasma processing apparatus according to claim 1 , wherein the outer ring extends so as to surround the edge ring. 6. The plasma processing apparatus according to claim 1, wherein the bias power supply is configured to supply high-frequency bias power to the bias electrode, or to periodically apply a pulsed voltage or a voltage having an arbitrary waveform to the bias electrode.

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