JP2022048089A - Placing table, substrate processing device, and suction method - Google Patents

Abstract

[Problem] To provide a mounting table, a substrate processing apparatus, and a chucking method that can suppress unevenness in chucking force and reduce costs. [Solution] The mounting table includes a base, an electrostatic chuck provided on the base and having two or more n-pole electrodes inside, and a power supply that applies two or more n-phase voltages that are out of phase with each other and whose positive and negative polarities alternate periodically to the n-pole electrodes, the n-pole electrodes being arranged alternately. [Selected Figure] Figure 2

Description

The present disclosure relates to a mounting table, a substrate processing apparatus, and an adsorption method.

A mounting table that adsorbs a substrate is known in a processing apparatus that performs a desired treatment such as an etching treatment on the substrate.

According to Patent Document 1, in an electrostatic chuck device to which an AC voltage is applied, the AC voltage is an n-phase AC voltage having n = 2 or more, and between the electrode to which the n-phase AC voltage is applied and each of the electrodes. Disclosed is an electrostatic chuck device including a sample table made of an insulator that insulates the voltage, and a circuit for applying the n-phase AC voltage.

Japanese Patent Application Laid-Open No. 2003-332912

In one aspect, the present disclosure provides a mounting table, a substrate processing apparatus, and a suction method capable of suppressing unevenness in suction force and reducing costs.

In order to solve the above problems, according to one embodiment, the base, an electrostatic chuck provided on the base and having two or more n-pole electrodes inside, and the n-pole electrode are used. A mounting table is provided in which two or more n-phases having two or more phases different from each other are provided with a power supply for applying a voltage in which positive and negative are periodically switched, and the n-pole electrodes are alternately arranged.

According to one aspect, it is possible to provide a mounting table, a substrate processing device, and a suction method capable of suppressing unevenness in suction force and reducing costs.

The sectional schematic diagram which shows an example of the plasma processing apparatus which concerns on one Embodiment. The plan view which shows an example of the arrangement of the electrode of an electrostatic chuck. The cross-sectional view which shows an example of the arrangement of the electrode of an electrostatic chuck. (A) is a graph showing an example of a three-phase AC voltage applied to an electrode, and (b) is a graph showing an example of the total adsorption force when a three-phase AC voltage is applied. (A) is a graph showing an example of a two-phase AC voltage applied to an electrode, and (b) is a graph showing an example of the total adsorption force when a two-phase AC voltage is applied. The plan view which shows an example of the arrangement of the electrode of the electrostatic chuck which concerns on a reference example. The plan view which shows an example of the arrangement of the electrode of the electrostatic chuck which concerns on other reference examples. The plan view which shows the other example of the arrangement of the electrode of an electrostatic chuck. A graph illustrating an example of an applied voltage waveform of a power supply.

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate explanations may be omitted.

[Plasma processing equipment]
The plasma processing apparatus 1 according to the embodiment will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing an example of the plasma processing apparatus 1 according to the embodiment. The plasma processing device 1 according to one embodiment is a capacitive coupling type parallel plate processing device and has a chamber 10. The chamber 10 is, for example, a cylindrical container made of aluminum whose surface has been anodized, and is grounded.

At the bottom of the chamber 10, a columnar support base 14 is arranged via an insulating plate 12 made of ceramics or the like, and for example, a mounting base 16 is provided on the support base 14. The mounting table 16 has an electrostatic chuck 20 and a base 16a, and the wafer W is mounted on the upper surface of the electrostatic chuck 20. An annular edge ring 24 made of, for example, silicon is arranged around the wafer W. The edge ring 24 is also called a focus ring. The edge ring 24 is an example of an outer peripheral member arranged around the mounting table 16. An annular insulator ring 26 made of, for example, quartz is provided around the base 16a and the support base 14. Inside the center side of the electrostatic chuck 20, a first electrode 20a made of a conductive film is sandwiched between the insulating layers 20b. The first electrode 20a is connected to the power supply 22. The voltage applied from the power supply 22 to the first electrode 20a causes a potential difference between the surface of the electrostatic chuck 20 and the wafer W which is the object to be adsorbed, and the object to be adsorbed on the wafer mounting surface of the electrostatic chuck 20. Adsorbs a certain wafer W. Further, inside the outer peripheral side of the electrostatic chuck 20, a second electrode 20c made of a conductive film is sandwiched between the insulating layers 20b. The second electrode 20c is connected to the power supply 23. The voltage applied from the power supply 23 to the second electrode 20c causes a potential difference between the surface of the electrostatic chuck 20 and the edge ring 24 which is an object to be adsorbed, and is adsorbed on the edge ring mounting surface of the electrostatic chuck 20. The edge ring 24, which is an object, is adsorbed. The electrostatic chuck 20 may have a heater, whereby the temperature may be controlled.

Inside the support base 14, for example, a ring-shaped or spiral-shaped refrigerant chamber 28 is formed. A refrigerant having a predetermined temperature supplied from the chiller unit (not shown), for example, cooling water, passes through the pipe 30a, the refrigerant chamber 28, and the pipe 30b and is returned to the chiller unit. By circulating the path through which the refrigerant is applied, the temperature of the wafer W can be controlled by the temperature of the refrigerant. Further, a heat transfer gas supplied from a heat transfer gas supply mechanism (not shown), for example, He gas, is supplied to a gap between the front surface of the electrostatic chuck 20 and the back surface of the wafer W via the gas supply line 32. .. This heat transfer gas increases the heat transfer coefficient between the front surface of the electrostatic chuck 20 and the back surface of the wafer W, making it more effective to control the temperature of the wafer W by the temperature of the refrigerant. Further, when the electrostatic chuck 20 has a heater, the temperature of the wafer W can be controlled with high responsiveness and high accuracy by heating with the heater and cooling with the refrigerant. Further, the heat transfer gas supplied from the heat transfer gas supply mechanism (not shown), for example, He gas, is connected to the front surface of the electrostatic chuck 20 and the back surface of the edge ring 24 via the gas supply line (not shown). It may be configured to be supplied even in a gap. Further, by controlling the pressure of the He gas supplied in the gap between the front surface of the electrostatic chuck 20 and the back surface of the object to be adsorbed (wafer W, edge ring 24), the electrostatic chuck 20 and the object to be adsorbed (wafer W) are controlled. , The heat transfer characteristic with the edge ring 24) may be controlled, and the temperature of the object to be adsorbed (wafer W, edge ring 24) may be controlled.

The upper electrode 34 is provided on the ceiling of the chamber 10 facing the mounting table 16. A plasma processing space is formed between the upper electrode 34 and the mounting table 16. The upper electrode 34 closes the opening of the ceiling portion of the chamber 10 via the insulating shielding member 42. The upper electrode 34 has an electrode plate 36 and an electrode support 38. The electrode plate 36 has a large number of gas discharge holes 37 formed on the surface facing the mounting table 16, and is formed of a silicon-containing material such as silicon or SiC. The electrode support 38 detachably supports the electrode plate 36 and is formed of a conductive material, for example, aluminum whose surface has been anodized. Inside the electrode support 38, a large number of gas flow holes 41a and 41b extend downward from the gas diffusion chambers 40a and 40b and communicate with the gas discharge holes 37.

The gas introduction port 62 is connected to the processing gas supply source 66 via the gas supply pipe 64. The gas supply pipe 64 is provided with a mass flow controller (MFC) 68 and an on-off valve 70 in this order from the upstream side where the processing gas supply source 66 is arranged. The processing gas is supplied from the processing gas supply source 66, the flow rate and opening / closing are controlled by the mass flow controller 68 and the opening / closing valve 70, and the gas diffusion chambers 40a and 40b and the gas flow holes 41a and 41b are passed through the gas supply pipe 64. It is discharged like a shower from the through gas discharge hole 37.

The plasma processing apparatus 1 has a first high frequency power supply 90 and a second high frequency power supply 48. The first high frequency power source 90 is a power source that generates the first high frequency power (hereinafter, also referred to as “HF power”). The first high frequency power has a frequency suitable for plasma generation. The frequency of the first high frequency power is, for example, a frequency in the range of 27 MHz to 100 MHz. The first high frequency power supply 90 is connected to the base 16a via the matching unit 88 and the feeding line 89. The matching device 88 has a circuit for matching the output impedance of the first high frequency power supply 90 with the impedance on the load side (base 16a side). The first high frequency power supply 90 may be connected to the upper electrode 34 via the matching device 88.

The second high frequency power supply 48 is a power supply that generates a second high frequency power (hereinafter, also referred to as “LF power”). The second high frequency power has a lower frequency than the frequency of the first high frequency power. When the second high frequency power is used together with the first high frequency power, the second high frequency power is used as the high frequency power for bias for drawing ions into the wafer W. The frequency of the second high frequency power is, for example, a frequency in the range of 400 kHz to 13.56 MHz. The second high frequency power supply 48 is connected to the base 16a via the matching unit 46 and the feeding line 47. The matching unit 46 has a circuit for matching the output impedance of the second high-frequency power supply 48 with the impedance on the load side (base 16a side). A DC pulse may be used as a biasing power for drawing ions into the wafer W. In this case, the plasma processing apparatus 1 has a DC pulse power supply (not shown) instead of the second high frequency power supply 48. The DC pulse power supply is connected to the base 16a via the feeding line 47. Further, as the power for bias for drawing ions into the wafer W, a synthetic wave obtained by synthesizing a plurality of input voltages such as a DC pulse (square wave) and a triangular wave may be used. In this case, the plasma processing apparatus 1 has a power supply (not shown) that outputs a combined wave instead of the second high frequency power supply 48. The power source for outputting the combined wave is connected to the base 16a via the feeding line 47.

It should be noted that the plasma may be generated by using the second high frequency power without using the first high frequency power, that is, by using only a single high frequency power. In this case, the frequency of the second high frequency power may be a frequency larger than 13.56 MHz, for example, 40 MHz. The plasma processing device 1 does not have to include the first high frequency power supply 90 and the matching device 88. With such a configuration, the mounting table 16 also functions as a lower electrode. The upper electrode 34 also functions as a shower head for supplying gas.

The second variable power source 50 is connected to the upper electrode 34, and a DC voltage is applied to the upper electrode 34. The first variable power supply 55 is connected to the edge ring 24, and a DC voltage is applied to the edge ring 24. The thickness of the sheath on the edge ring 24 is controlled by applying a predetermined DC voltage corresponding to the consumption amount of the edge ring 24 from the first variable power supply 55 to the edge ring 24. This eliminates the step between the sheath on the edge ring 24 and the sheath on the wafer W, prevents the ion irradiation angle from becoming slanted at the edge portion of the wafer W, and prevents the recess formed on the wafer W from becoming slanted. Avoid the occurrence of tilting that makes the shape slanted.

The exhaust device 84 is connected to the exhaust pipe 82. The exhaust device 84 has a vacuum pump such as a turbo molecular pump, and exhausts air from an exhaust port 80 formed at the bottom of the chamber 10 through an exhaust pipe 82 to reduce the pressure in the chamber 10 to a desired degree of vacuum. Further, the exhaust device 84 controls the pressure in the chamber 10 to be constant while using the value of the pressure gauge for measuring the pressure in the chamber 10 (not shown). The carry-in outlet 85 is provided on the side wall of the chamber 10. The wafer W is carried in and out from the carry-in outlet 85 by opening and closing the gate valve 86.

The baffle plate 83 is provided in an annular shape between the insulator ring 26 and the side wall of the chamber 10. The baffle plate 83 has a plurality of through holes, is made of aluminum _, and its surface is coated with ceramics such as _Y2O3 .

When performing a predetermined plasma processing such as plasma etching processing in the plasma processing apparatus 1 having such a configuration, the gate valve 86 is opened, the wafer W is carried into the chamber 10 through the carry-in outlet 85, and the electrostatic chuck 20 is subjected to. Place it on the wafer mounting surface and close the gate valve 86. Further, the edge ring 24 is mounted on the edge ring mounting surface of the electrostatic chuck 20. The processing gas is supplied to the inside of the chamber 10 and the inside of the chamber 10 is exhausted by the exhaust device 84.

The first high frequency power and the second high frequency power are applied to the mounting table 16. Then, the power supply 22 applies a voltage to the first electrode 20a of the electrostatic chuck 20 to attract the wafer W to the wafer mounting surface of the electrostatic chuck 20. Further, the power supply 23 applies a voltage to the second electrode 20c of the electrostatic chuck 20 to attract the edge ring 24 to the edge ring mounting surface of the electrostatic chuck 20. A DC voltage may be applied from the second variable power source 50 to the upper electrode 34.

Plasma treatment such as etching is performed on the surface to be processed of the wafer W by radicals and ions in the plasma generated in the plasma processing space.

The plasma processing apparatus 1 is provided with a control unit 200 that controls the operation of the entire apparatus. The CPU provided in the control unit 200 executes a desired plasma process such as etching according to a recipe stored in a memory such as a ROM and a RAM. In the recipe, process time, pressure (gas exhaust), first high frequency power and second high frequency power and voltage, and various gas flow rates, which are control information of the device for process conditions, may be set. Further, the temperature inside the chamber (upper electrode temperature, side wall temperature of the chamber, wafer W temperature, electrostatic chuck temperature, etc.), the temperature of the refrigerant output from the chiller, and the like may be set in the recipe. The recipes showing these programs and processing conditions may be stored in a hard disk or a semiconductor memory. Further, the recipe may be set in a predetermined position and read out in a state of being housed in a storage medium readable by a portable computer such as a CD-ROM or a DVD.

Next, the arrangement of the electrodes of the electrostatic chuck 20 on the mounting table 16 will be further described with reference to FIGS. 2 and 3. FIG. 2 is a plan view showing an example of the arrangement of the electrodes 20a and 20c of the electrostatic chuck 20. FIG. 3 is a cross-sectional view showing an example of the arrangement of the electrodes 20a and 20c of the electrostatic chuck 20. The electrostatic chuck 20 has a wafer mounting surface 20d1 on which the wafer W is mounted and an edge ring mounting surface 20d2 on which the edge ring 24 is mounted. Note that FIG. 3 is a cross-sectional view cut at the position of the broken line in FIG. 2, for example.

As shown in FIGS. 2 and 3, the first electrode 20a on the wafer mounting surface 20d1 has two or more n-pole electrodes. In the example of the electrostatic chuck 20 shown in FIGS. 2 and 3, the first electrode 20a is a three-pole electrode and has electrodes 20a1, 20a2, 20a3.

The electrodes 20a1 are arranged in a spiral shape about the central axis of the electrostatic chuck 20. In other words, the electrodes 20a1 are formed from the center side to the outer peripheral side of the wafer mounting surface 20d1 and are formed in a spiral shape so that the radius of gyration increases as the rotation angle increases. That is, the electrodes 20a1 are arranged over the entire circumference in the circumferential direction about the central axis of the electrostatic chuck 20, and extend from the central portion of the wafer mounting surface 20d1 to the peripheral edge portion (outer peripheral portion). Have been placed. Similarly, the electrodes 20a2 and 20a3 are arranged in a spiral shape.

The electrodes 20a1, 20a2, 20a3 have an area ratio of 1. That is, the electrodes 20a1, 20a2, 20a3 are formed to have the same area.

Further, the electrodes 20a1, 20a2, 20a3 are arranged coaxially with respect to the central axis of the electrostatic chuck 20 and are arranged with symmetry in the rotation direction. That is, the first electrode 20a composed of the three-pole electrodes has a rotational symmetry of 120 °. When the electrode 20a1 is rotated by 120 ° with the central axis of the electrostatic chuck 20 as the axis of rotation, it coincides with the electrode 20a2. When the electrode 20a1 is rotated by 240 °, it coincides with the electrode 20a3.

Further, as shown in FIG. 3, the electrode 20a3 is arranged adjacent to the inside of the electrode 20a1 in the radial direction, and the electrode 20a3 is arranged adjacent to the outside of the electrode 20a1 in the radial direction. The electrode 20a1 is arranged adjacent to the inside of the electrode 20a2 in the radial direction, and the electrode 20a3 is arranged adjacent to the outside of the electrode 20a2 in the radial direction. The electrodes 20a2 are arranged adjacent to each other on the inner side of the electrodes 20a3 in the closing direction, and the electrodes 20a1 are arranged adjacent to each other on the outer side in the radial direction of the electrodes 20a3.

A power supply 22 is connected to the electrodes 20a1, 20a2, and 20a3, respectively. The power supply 22 applies an AC voltage of two or more n-phases having different phases to the first electrode 20a of two or more n poles. In the example of the electrostatic chuck 20 shown in FIG. 2, the power supply 22 applies a three-phase AC voltage having different phases to the three-pole electrodes 20a1, 20a2, 20a3.

Next, the three-phase AC voltage applied to the first electrode 20a (electrodes 20a1, 20a2, 20a3) having three poles will be described with reference to FIG. 4A. FIG. 4A is a graph showing an example of a three-phase AC voltage applied to the electrodes 20a1, 20a2, 20a3. The vertical axis shows the applied voltage, and the horizontal axis shows the time. An example of the AC voltage applied to the electrode 20a1 is shown by a solid line graph, an example of the AC voltage applied to the electrode 20a2 is shown by a one-dot chain line graph, and an example of the AC voltage applied to the electrode 20a3 is shown by a broken line graph. show. The amplitude of the applied voltage is normalized as 1.

The AC voltages applied to the electrodes 20a1, 20a2, 20a3 by the power supply 22 have the same maximum amplitude, the same frequency, and different phases from each other. For example, the phase difference of the AC voltage applied to the electrodes 20a1, 20a2, 20a3 is set to 120 °.

The adsorption force of the wafer W when the three-phase AC voltage shown in FIG. 4A is applied to the first electrodes 20a (electrodes 20a1, 20a2, 20a3) will be described with reference to FIG. 4B. FIG. 4B is a graph showing an example of the total adsorption force of the wafer W when a three-phase AC voltage is applied to the electrodes 20a1, 20a2, 20a3. The vertical axis shows the total adsorption force, and the horizontal axis shows time. As shown in FIG. 4B, the suction force of the mounting table 16 for adsorbing the wafer W can be made constant.

Further, as shown in FIGS. 2 and 3, the second electrode 20c on the edge ring mounting surface 20d2 has two or more n-pole electrodes. In the example of the electrostatic chuck 20 shown in FIGS. 2 and 3, the second electrode 20c is a two-pole electrode and has electrodes 20c1 and 20c2.

The electrodes 20c1 are arranged in a spiral shape about the central axis of the electrostatic chuck 20. In other words, the electrode 20c1 is formed from the inner peripheral portion to the outer peripheral portion of the edge ring mounting surface 20d2, and is formed in a spiral shape so that the turning radius increases as the rotation angle increases. That is, the electrodes 20c1 are arranged over the entire circumference in the circumferential direction about the central axis of the electrostatic chuck 20, and are arranged from the inner peripheral portion to the outer peripheral portion of the edge ring mounting surface 20d2. ing. Similarly, the electrodes 20c2 are arranged in a spiral shape.

The electrodes 20c1 and 20c2 have an area ratio of 1. That is, the electrodes 20c1 and 20c2 are formed to have the same area.

Further, the electrodes 20c1 and 20c2 are arranged coaxially with respect to the central axis of the electrostatic chuck 20 and have symmetry in the rotation direction. That is, the second electrode 20c composed of the two-pole electrodes has a rotational symmetry of 180 °. When the electrode 20c1 is rotated by 180 ° with the central axis of the electrostatic chuck 20 as the axis of rotation, it coincides with the electrode 20c2.

Further, as shown in FIG. 3, the electrode 20c2 is arranged adjacent to the inside of the electrode 20c1 in the radial direction, and the electrode 20c2 is arranged adjacent to the outside of the electrode 20a1 in the radial direction. The electrode 20c1 is adjacent to the inside of the electrode 20c2 in the radial direction, and the electrode 20c1 is adjacent to the outside of the electrode 20a2 in the radial direction.

A power supply 23 is connected to the electrodes 20c1 and 20c2, respectively. The power supply 23 applies an AC voltage of two or more n-phases having different phases to the second electrode 20c of two or more n poles. In the example of the electrostatic chuck 20 shown in FIG. 2, the power supply 22 applies a two-phase AC voltage having different phases to the two-pole electrodes 20c1 and 20c2.

Next, the two-phase AC voltage applied to the second electrode 20c (electrodes 20c1, 20c2) having two poles will be described with reference to FIG. 5A. FIG. 5A is a graph showing an example of a two-phase AC voltage applied to the electrodes 20c1 and 20c2. The vertical axis shows the applied voltage, and the horizontal axis shows the time. An example of the AC voltage applied to the electrode 20c1 is shown by a solid line graph, and an example of the AC voltage applied to the electrode 20c2 is shown by a one-dot chain line graph. The amplitude of the applied voltage is normalized as 1.

The AC voltage applied to each of the electrodes 20c1 and 20c2 of the second electrode 20c by the power supply 23 has the same maximum amplitude, the same frequency, and different phases. For example, the phase difference of the AC voltage applied to the electrodes 20c1 and 20c2 is set to 90 °.

The adsorption force of the edge ring 24 when the two-phase AC voltage shown in FIG. 5 (a) is applied to the second electrodes 20c (20c1, 20c2) will be described with reference to FIG. 5 (b). FIG. 5B is a graph showing an example of the total adsorption force of the edge ring 24 when a two-phase AC voltage is applied to the electrodes 20c1 and 20c2. The vertical axis shows the total adsorption force, and the horizontal axis shows time. As shown in FIG. 5B, even if the number of poles of the second electrode 20c is two, the suction force by which the mounting table 16 sucks the edge ring 24 can be constant.

Further, in FIGS. 2 to 4, the number of poles of the first electrode 20a is 3 poles, and the number of poles of the second electrode 20c is 2 poles, but the present invention is not limited to this. Further, the number of poles of the first electrode 20a and the number of poles of the second electrode 20c may be 2 or more. Further, the number of poles of the first electrode 20a and the number of poles of the second electrode 20c may be the same or different.

Here, in the n-pole electrode, the n-phase AC voltage has an amplitude A and a period ω, and is represented by the following equation (1). Note that N is an individual integer corresponding to each electrode of n or less.

Asin (ωt + N / n × 360 °) ・ ・ ・ (1)

Further, in a certain electrode (for example, the electrode 20a2), the phase difference from the other electrode on the inner peripheral side (for example, the electrode 20a1) is (1 / n × 360 °), and the phase difference is (1 / n × 360 °), and the other electrode on the outer peripheral side (for example, the electrode 20a1). The phase difference from the electrode 20a3) is (1 / n × 360 °). Therefore, the potential difference between adjacent electrodes can be reduced. This makes it possible to suppress a short circuit between the electrodes.

In other words, the distance between the electrodes can be narrowed, and the area (radial width) of the electrodes can be widened. Thereby, the ratio occupied by the first electrode 20a on the wafer mounting surface 20d1 can be increased. Here, the suction force is generated at the position where the electrodes are formed, and the suction force is not generated in the insulating region between the electrodes. According to the electrostatic chuck 20, the suction force of the wafer W can be improved by increasing the area of the electrodes. In addition, the in-plane uniformity of the adsorption force can be improved. Although the first electrode 20a that adsorbs the wafer W has been described as an example, the same applies to the second electrode 20c that adsorbs the edge ring 24.

Further, it is preferable that the number of electrodes of the electrodes is 6 poles or more and an AC voltage of 6 phases or more is used. For example, in the case of a 6-phase AC voltage, the phase difference between adjacent electrodes is 60 °, and the potential difference between adjacent electrodes is at most an amplitude A or less. This makes it possible to suppress a short circuit between the electrodes. Further, by narrowing the distance between the electrodes and widening the area (radial width) of the electrodes, the adsorption force can be improved and the in-plane uniformity of the adsorption force can be improved. Further, as the number of electrodes (the number of phases of the AC voltage) increases, these effects can be improved.

Further, since the electrodes 20a1, 20a2, 20a3 are formed in a spiral shape, it is possible to suppress unevenness in the circumferential direction of the adsorption force of the wafer W by the electrostatic chuck 20.

Here, the electrostatic chuck 20 according to the reference example will be described with reference to FIGS. 6 and 7. FIG. 6 is a plan view showing an example of the arrangement of the electrodes 20X1 of the electrostatic chuck according to the reference example. In the example of electrode arrangement shown in FIG. 6, the electrodes are partitioned in the radial direction and the circumferential direction, and the three-pole electrodes shown by A, B, and C are alternately arranged. As a result, it has symmetry in the circumferential direction. FIG. 7 is an example of a plan view showing an example of the arrangement of the electrodes 20X2 of the electrostatic chuck according to another reference example. In the example of electrode arrangement shown in FIG. 7, the electrodes are divided into hexagons, and the three-pole electrodes shown by A, B, and C are arranged alternately. As a result, it has symmetry in the circumferential direction.

However, in the electrode arrangement examples shown in FIGS. 6 and 7, the electrodes corresponding to one pole are divided into a plurality of electrodes, and the wiring between each electrode and the power supply 22 is branched into a plurality of electrodes, and each electrode and the power supply 22 are connected. There are also multiple connection points.

On the other hand, in the electrostatic chuck 20 shown in FIG. 2, the spirally formed electrodes 20a1, 20a2, 20a3 are connected to the power supply 22 at one point each. This makes it possible to reduce the manufacturing cost of the electrostatic chuck 20.

As shown in FIG. 2, the electrostatic chuck 20 has been described as having the electrodes 20a1, 20a2, 20a3 arranged in a spiral shape as the first electrode 20a for adsorbing the wafer W, but the present invention is limited to this. It's not a thing. The first electrode 20a has two or more n-pole electrodes, the n-pole electrodes are arranged alternately, and the n-pole electrodes and the power supply 22 are connected at one point each. You may.

Another example of the arrangement of the electrodes of the electrostatic chuck 20 will be described with reference to FIG. FIG. 8 is a plan view showing another example of the arrangement of the electrodes of the electrostatic chuck 20. The first electrode 20a may be formed in a comb-teeth shape. That is, the first electrode 20a has an electrode 20a1 and an electrode 20a2. The electrode 20a1 has an arc-shaped base connected to the power supply 22, and a plurality of branch portions (tooth portions) branched from the base portion and extending in parallel. Similarly, the electrode 20a2 has an arc-shaped base connected to the power supply 22, and a plurality of branch portions (teeth portions) branched from the base portion and extending in parallel. Further, the branched portions of the electrodes 20a1 and 20a2 are arranged alternately, that is, the branched portions of the electrodes 20a2 are arranged between the branched portions of the electrodes 20a1 and the branched portions of the electrodes 20a1. The branch portion of the electrode 20a1 is arranged between the branch portion of the electrode 20a2 and the branch portion of the electrode 20a2. Further, when looking at the cross section of the electrostatic chuck 20 cut at the position of the broken line in FIG. 8, the branched portion of the electrode 20a1 and the branched portion of the electrode 20a2 are alternately arranged. Further, the electrodes 20a1 and 20a2 are connected to the power supply 22 at one point each.

As described above, the electrostatic chuck 20 having the comb-shaped electrodes 20a1 and 20a2 shown in FIG. 8 has the same attractive force as the electrostatic chuck 20 having the spiral electrodes 20a1 to 20a3 shown in FIG. Unevenness can be suppressed and the manufacturing cost of the electrostatic chuck 20 can be reduced.

In FIG. 8, the case of the electrode 20a1 that adsorbs the wafer W has been described as an example, but the electrode 20a2 that adsorbs the edge ring 24 also has two or more n-pole electrodes, and the n-pole electrodes alternate. The n-pole electrode and the power supply 22 may be connected to each other at one point each. For example, the electrodes 20a2 may be formed in a comb-teeth shape. Further, the shapes of the electrodes 20a1 and 20a2 may be different. For example, one of the electrodes 20a1 and 20a2 may be formed in a spiral shape and the other may be formed in a comb-teeth shape.

Further, the power supplies 22 and 23 have been described as being power supplies to which an AC voltage is applied, but the present invention is not limited thereto. The power supplies 22 and 23 may be power supplies that apply an AC voltage whose positive and negative are periodically switched. In other words, the power supplies 22 and 23 may be power supplies to which an AC voltage that periodically repeats the maximum value of the amplitude and the minimum value of the amplitude is applied. In other words, the power supplies 22 and 23 may be power supplies to which an AC voltage that repeatedly increases and decreases periodically is applied.

An example of the applied voltage waveform of the power supply will be described with reference to FIG. FIG. 9 is a graph illustrating an example of the applied voltage waveform of the power supply. In FIG. 9, the horizontal axis represents time and the vertical axis represents the applied voltage. The amplitude of the applied voltage is normalized as 1.

As shown in FIG. 9A (also see FIGS. 4A and 5A), the power supplies 22 and 23 may be power supplies to which a sinusoidal voltage is applied.

Further, as shown in FIG. 9B, the power supplies 22 and 23 may be power supplies to which a rectangular wave voltage is applied. The applied voltage of the rectangular wave periodically repeats that the maximum applied voltage is maintained for a predetermined time and then suddenly drops, and the minimum applied voltage is maintained for a predetermined time and then rapidly rises. As a result, the applied voltage of the square wave is periodically switched between positive and negative.

Further, as shown in FIG. 9C, the power supplies 22 and 23 may be power supplies to which a triangular wave voltage is applied. As for the applied voltage of the triangular wave, the applied voltage increases from the minimum value to the maximum value, and the applied voltage decreases from the maximum value to the minimum value, which is repeated periodically. As a result, the applied voltage of the triangular wave is periodically switched between positive and negative.

Further, as shown in FIG. 9D, the power supplies 22 and 23 may be power supplies to which a sawtooth wave voltage is applied. As for the applied voltage of the sawtooth wave, the applied voltage gradually increases from the minimum value to the maximum value, and the applied voltage rapidly decreases from the maximum value to the minimum value, which is periodically repeated. As a result, the applied voltage of the sawtooth wave is periodically switched between positive and negative.

Further, although not shown, the power supplies 22 and 23 may be power supplies to which a reverse sawtooth voltage is applied. As for the applied voltage of the reverse sawtooth wave, the applied voltage rapidly increases from the minimum value to the maximum value, and the applied voltage gradually decreases from the maximum value to the minimum value, which is periodically repeated. As a result, the applied voltage of the reverse sawtooth wave is periodically switched between positive and negative.

Further, although not shown, the power supplies 22 and 23 may be power supplies to which a pseudo sine wave voltage is applied. The applied voltage of the pseudo sine wave periodically repeats that the maximum applied voltage is maintained for a predetermined time and then decreases in multiple stages, and the minimum applied voltage is maintained for a predetermined time and then increased in multiple stages. As a result, the applied voltage of the pseudo sine wave is periodically switched between positive and negative.

Further, as shown in FIGS. 4, 5, and 9 (a) to 9 (d), the waveforms of the power supplies 22 and 23 have the same positive and negative periods and amplitudes at a voltage in which positive and negative are periodically switched. preferable.

Although the embodiments of the plasma processing apparatus 1 have been described above, the present disclosure is not limited to the above embodiments and the like, and various modifications are made within the scope of the gist of the present disclosure described in the claims. , Improvement is possible.

In the case where the electrodes have two poles, the AC voltage shown in FIG. 4 is applied, but the present invention is not limited to this. A voltage of opposite phase may be applied. As a result, adsorption by Johnson Rabeck force can be performed.

1 Plasma processing equipment (board processing equipment)
16 Mounting base 16a Base 20 Electrostatic chuck 20a First electrode 20b Insulation layer 20c Second electrode 20d1 Wafer mounting surface 20d2 Edge ring mounting surface 20a1, 20a2, 20a3, 20c1, 20c2 Electrode 24 Edge ring (annular member) )
W wafer (board)

Claims (14)

Base and
An electrostatic chuck provided on the base and having two or more n-pole electrodes inside,
The n-pole electrode is provided with a power supply for applying a voltage in which two or more n-phases having different phases are periodically switched between positive and negative.
The n-pole electrodes are arranged alternately.
Mounting stand. The power supply applies an AC voltage.
The mounting table according to claim 1. The power supply applies any voltage of a rectangular wave, a triangular wave, and a sawtooth wave.
The mounting table according to claim 1. The n-pole electrodes are arranged in a spiral shape.
The mounting table according to any one of claims 1 to 3. The n-pole electrode has a base connected to the power supply and a branch portion branched from the base, respectively.
The branches of the n-pole electrode are arranged alternately.
The mounting table according to any one of claims 1 to 3. The n-pole electrode has an area ratio of 1 between the electrodes.
The mounting table according to any one of claims 1 to 5. The n-pole electrodes are formed in rotational symmetry with each other.
The mounting table according to any one of claims 1 to 6. The n-phase AC voltage has a phase difference of 1 / n × 360 °.
The mounting table according to any one of claims 1 to 7. The n-pole electrode has 6 or more poles.
The mounting table according to any one of claims 1 to 8. The electrostatic chuck attracts the substrate.
The mounting table according to any one of claims 1 to 9. The electrostatic chuck attracts an annular member arranged on the outer periphery of the substrate.
The mounting table according to any one of claims 1 to 10. A substrate processing apparatus comprising the mounting table according to any one of claims 1 to 11. An adsorption method in which an object to be adsorbed, which is at least one of a substrate or an edge ring, is adsorbed on a mounting table having two or more n-pole electrodes and having electrostatic chucks arranged alternately. There,
A voltage whose positive and negative are periodically switched is applied to the n-pole electrode of two or more n-phases having different phases from each other.
Adsorption method. The phase difference of the n-phase AC voltage is represented by 1 / n × 360 °.
The adsorption method according to claim 13.

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