Focus ring, chuck assembly for securing a substrate, and plasma processing apparatus

Abstract

A focusing ring, a chuck assembly for fixing a substrate, and a plasma processing apparatus are provided. The focusing ring includes: a first conductive layer having a first thickness and a first resistivity; a second conductive layer stacked on the first conductive layer, the second conductive layer having a second thickness greater than the first thickness and a second resistivity greater than the first resistivity; and a dielectric layer located on one of the lower surface of the first conductive layer and the upper surface of the second conductive layer.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2020-0036800, filed on March 26, 2020, entitled “Focusing Ring, Chuck Assembly for Fixing a Substrate with Focusing Ring and Plasma Processing Apparatus with Focusing Ring”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The example embodiments relate to a focusing ring, a chuck assembly having the focusing ring for fixing a substrate, and a plasma processing apparatus having the focusing ring. More specifically, they relate to a focusing ring located around a chuck assembly to which high-frequency power for generating plasma is applied, as well as a chuck assembly having the focusing ring and a plasma etching apparatus having the focusing ring. Background Technology

[0003] The uniformity of plasma density affects the etching quality of plasma etching processes. Therefore, a focusing ring is typically provided for most plasma etching equipment. The focusing ring can be arranged around a chuck to which the substrate is fixed, and the substrate is surrounded by the focusing ring. The plasma in the plasma space is focused onto the substrate by the focusing ring, thereby increasing the plasma density on the substrate. The chuck for fixing the substrate and the focusing ring around the chuck for focusing the plasma onto the substrate can be combined into a chuck assembly as the lower structure of the plasma processing equipment. Summary of the Invention

[0004] According to an example embodiment, a focusing ring is provided, the focusing ring comprising: a first conductive layer having a first thickness and a first specific resistance; a second conductive layer stacked on the first conductive layer having a second thickness greater than the first thickness and a second specific resistance greater than the first specific resistance; and a dielectric layer disposed on one of the lower surface of the first conductive layer and the upper surface of the second conductive layer.

[0005] According to other example embodiments, a chuck assembly is provided, the chuck assembly comprising: a chuck dielectric plate comprising a dielectric material, and a substrate being fixed to the chuck dielectric plate; a chuck body comprising a conductive material, and supporting the chuck dielectric plate such that at least one high-frequency power can be applied to the chuck body; and a focusing ring disposed on a peripheral portion of the chuck body such that a substrate can be surrounded by the focusing ring, and the focusing ring may include a composite conductive layer and a ring dielectric layer disposed on one of a lower surface and an upper surface of the composite conductive layer, wherein at least two conductive layers with different specific resistances may be stacked in the composite conductive layer.

[0006] According to other example embodiments, a plasma processing apparatus is provided for performing a plasma processing process on a substrate. The plasma processing apparatus may include: a processing chamber having a processing space in which the plasma processing process can be performed; a source supplier disposed at the upper part of the processing chamber and supplying a source gas for the plasma processing process; a chuck assembly disposed at the lower part of the processing chamber and fixing the substrate; and a power source that applies at least one high-frequency power to the chuck assembly and generates plasma for the plasma processing process in the processing space. Specifically, the chuck assembly may include: a chuck dielectric plate comprising a dielectric material, to which the substrate can be fixed; a chuck body comprising a conductive material and supporting the chuck dielectric plate such that at least the high-frequency power can be applied to the chuck body; and a focusing ring disposed on a peripheral portion of the chuck body such that the substrate can be surrounded by the focusing ring. The focusing ring may include: a composite conductive layer in which at least two conductive layers with different specific resistances may be stacked; and a ring dielectric layer disposed on one of the lower and upper surfaces of the composite conductive layer. Attached Figure Description

[0007] Features will become apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, in which:

[0008] Figure 1 This is a perspective view showing a focusing ring for a chuck assembly according to an example embodiment;

[0009] Figure 2 It is shown Figure 1 A cross-sectional view of the construction of the focusing ring relative to the substrate;

[0010] Figure 3 It is shown Figure 2 A view showing the modified construction of the focusing ring relative to the substrate;

[0011] Figure 4 This illustrates the inclusion of, according to an example embodiment. Figure 1 and Figure 2 The diagram shows the structure of the chuck assembly for the focusing ring.

[0012] Figure 5 It is shown Figure 4 A plan view of the chuck dielectric plate and the ring dielectric layer of the focusing ring in the chuck assembly shown;

[0013] Figure 6A This is a perspective view showing the first transmission line in which the chuck dielectric plate and substrate are stacked;

[0014] Figure 6B This is a perspective view showing a second transmission line in which a ring dielectric layer and a composite conductive layer are stacked;

[0015] Figure 7 This is a graph showing the relationship between the resistivity of the first conductive layer of the focusing ring and the intensity difference between the first and second transmitted power signals, relative to various thicknesses of the first conductive layer; and

[0016] Figure 8 This illustrates a method according to an example embodiment with... Figure 4 The diagram shows a structural diagram of a plasma processing device with a chuck assembly. Detailed Implementation

[0017] Reference will now be made to exemplary embodiments, which are illustrated in the accompanying drawings, wherein the same reference numerals always denote the same components.

[0018] Figure 1 This is a perspective view showing a focusing ring for a chuck assembly according to an example embodiment. Figure 2 It is along Figure 1 The cross-sectional view of the focusing ring along line I-I' shown.

[0019] Reference Figure 1 and Figure 2 According to an example embodiment, the focusing ring 90 may include a first conductive layer 10 having a first resistivity ρ1 and a first thickness t1, a second conductive layer 20 stacked on the first conductive layer 10 and having a second resistivity ρ2 greater than the first resistivity ρ1 and a second thickness t2 greater than the first thickness t1, and a dielectric layer 30 disposed on at least one of the lower surface of the first conductive layer 10 and the upper surface of the second conductive layer 20. For example, as Figure 1 and Figure 2 As shown, the dielectric layer 30 can be arranged under the first conductive layer 10 in such a configuration that the dielectric layer 30, the first conductive layer 10 and the second conductive layer 20 can be stacked sequentially on top of each other (e.g., the first conductive layer 10 can be located between the second conductive layer 20 and the dielectric layer 30).

[0020] In this example embodiment, the focusing ring 90 can be combined with a device for using chlorine fluoride (Cl... x F y A chuck assembly for a plasma etching process using a source gas.

[0021] In this example embodiment, high-frequency power can be applied to the lower part of the chuck assembly and transmitted through the substrate W and focusing ring 90, thereby generating plasma for the plasma etching process in the plasma space above the substrate W and focusing ring 90. The high-frequency power transmitted through the focusing ring 90 can generate plasma on the peripheral portion E of the substrate W and the focusing ring 90, and can also generate plasma on most of the substrate W except for the peripheral portion E. Hereinafter, the portion of the substrate W excluding the peripheral portion E can be referred to as the central portion C; for example, the peripheral portion E can represent the edge portion of the substrate.

[0022] The first conductive layer 10 may have a resistivity and thickness such that the attenuation of high-frequency power passing through the first conductive layer 10 is substantially the same as the attenuation of high-frequency power passing through the substrate W. For this reason, the first conductive layer 10 may have a first resistivity ρ1 and a first thickness t1. Conversely, the second conductive layer 20 may have a resistivity and thickness such that the high-frequency power transmitted through the first conductive layer 10 can be transmitted through the second conductive layer 20 with substantially no attenuation. For this reason, the second conductive layer 20 may have a second resistivity ρ2 and a second thickness t2.

[0023] For example, the second specific resistance ρ2 can be about 10 to about 100 times that of the first specific resistance ρ1, where the first specific resistance ρ1 can make the attenuation of the high-frequency power substantially the same as the attenuation of the high-frequency power transmitted through the substrate W. In this example embodiment, the first specific resistance ρ1 can be in the range of about 10 Ωcm to about 100 Ωcm.

[0024] The second conductive layer 20 can be stacked on the first conductive layer 10, and high-frequency power can be sequentially transmitted toward the plasma space through the first conductive layer 10 and the second conductive layer 20 of the focusing ring 90.

[0025] In detail, the second conductive layer 20 can have a much higher resistivity than the first conductive layer 10, allowing high-frequency power to be transmitted through the second conductive layer 20 with virtually no attenuation. Therefore, the central intensity of the high-frequency power (which is the intensity of the high-frequency power transmitted through the chuck and the substrate W at the central portion C of the substrate W) can approach the peripheral intensity of the high-frequency power (which is the intensity of the high-frequency power transmitted through the focusing ring 90 around the peripheral portion E of the substrate W). That is, the intensity difference between the high-frequency power transmitted through the substrate W and the high-frequency power transmitted through the focusing ring 90 can be minimized through the first conductive layer 10 and the second conductive layer 20 of the focusing ring 90.

[0026] The second conductive layer 20 can be directly exposed to plasma during the plasma processing, that is, exposed to plasma in the plasma space above the second conductive layer 20 of the focusing ring 90. Therefore, the second conductive layer 20 may include an etch-resistant material (e.g., an etch-resistant material that protects the second conductive layer 20 from the effects of plasma above the focusing ring 90).

[0027] The first conductive layer 10 can be covered by the second conductive layer 20, thus the first conductive layer 10 is not directly exposed to plasma during the plasma processing. Therefore, no thickness loss occurs in the first conductive layer 10 despite repeated plasma processing. Since high-frequency power attenuates when transmitted through the first conductive layer 10 and attenuates substantially during transmission through the second conductive layer 20, the overall attenuation of high-frequency power can be controlled solely by controlling the construction of the first conductive layer 10 and the second conductive layer 20. That is, the first conductive layer 10 and the second conductive layer 20 can be used as a composite conductive layer 50 for controlling the overall attenuation of high-frequency power transmitted through the focusing ring 90.

[0028] In this example embodiment, the first conductive layer 10 may include doped silicon (Si) having a first specific resistance ρ1 of about 100 Ωcm. The second conductive layer 20 may include doped silicon carbide (SiC) having a second specific resistance ρ2 of about 1,000 Ωcm to about 10,000 Ωcm.

[0029] However, the first conductive layer 10 and the second conductive layer 20 may comprise any other conductive material, provided that high-frequency power can be sufficiently transmitted with high controlled attenuation. Specifically, the second conductive layer 20 may comprise various conductive materials, provided that the conductive material has sufficient etch resistance at high temperatures and does not generate particles from the conductive material.

[0030] The first thickness t1 of the first conductive layer 10 can be determined in relation to the first specific resistance ρ1 in such a way that the attenuation of the high-frequency power transmitted through the first conductive layer 10 is substantially the same as the attenuation of the high-frequency power transmitted through the substrate W. For example, when the first conductive layer 10 comprises the same material as the substrate W, the thickness of the first conductive layer 10 can be substantially the same as the thickness of the substrate W.

[0031] The second conductive layer 20 may have a second thickness t2 corresponding to the remaining portion (e.g., the remaining portion) of the total thickness T of the focusing ring 90 excluding the first conductive layer 10 and the dielectric layer 30. For example, as Figure 2 As shown, the sum of the second thickness t2 of the conductive layer 20, the first thickness t1 of the first conductive layer 10, and the third thickness t3 of the dielectric layer 30 can constitute the total thickness T of the focusing ring 90.

[0032] The total thickness T of the focusing ring 90 can vary depending on the requirements of the plasma processing process and the characteristics of the chuck assembly. In this example embodiment, the focusing ring 90 can have a total thickness T of approximately 3 mm to approximately 6 mm. Therefore, the second thickness t2 of the second conductive layer 20 can be determined as the difference between the total thickness T of the focusing ring 90 and the sum of the thicknesses of the first conductive layer 10 and the dielectric layer 30.

[0033] When high-frequency power is transmitted through the focusing ring 90 and the substrate W, the dielectric layer 30 can reduce the phase difference of the high-frequency power. For example, the dielectric layer 30 may include at least one of aluminum oxide (Al2O3), yttrium oxide (Y2O3), aluminum nitride (AlN), quartz, and combinations thereof.

[0034] In detail, since the chuck and substrate W of the chuck assembly can include resistive and dielectric materials, and high-frequency power can be transmitted towards the plasma space through the chuck and substrate W, the chuck and substrate W can be simplified as an RC circuit when high-frequency power is applied to the lower part of the chuck assembly. Therefore, due to the resistance of the resistive material and the capacitance of the dielectric material, the high-frequency power will have a time delay at the substrate W. Thus, when the high-frequency power is transmitted through the substrate W and the focusing ring 90, a phase difference will occur between the power transmitted at the substrate W and the power transmitted at the focusing ring 90. Hereinafter, the high-frequency power applied to the lower part of the chuck assembly is referred to as the applied power signal, and the high-frequency power transmitted through the substrate W or the focusing ring 90 is referred to as the transmitted power signal.

[0035] The phase difference in transmitted electrical signals is typically caused by both resistance and capacitance. However, the phase difference in transmitted electrical signals is more caused by capacitance than resistance. Therefore, when the capacitance of the focusing ring 90 is substantially the same as the capacitance of the chuck in the chuck assembly, the phase difference in the transmitted electrical signal between the upper part of the substrate and the focusing ring 90 can be minimized. That is, when the focusing ring 90 has the same capacitance as the chuck in the chuck assembly, the phase difference in the transmitted electrical signal at the focusing ring 90 can be approximated as the phase difference in the transmitted electrical signal at the substrate W, although they are not identical.

[0036] In this example embodiment, the third thickness t3 of the dielectric layer 30 can be adjusted so that the capacitance of the dielectric layer 30 is substantially the same as the capacitance of the dielectric body of the chuck. Therefore, the total thickness T of the focusing ring 90 can be the sum of the first thickness t1, the second thickness t2, and the third thickness t3, and can be in the range of about 3 mm to about 6 mm.

[0037] The first conductive layer 10 and the second conductive layer 20 can be combined with each other to form a composite conductive layer 50 of the focusing ring 90 without any intermediate components. For example, the first conductive layer 10 and the second conductive layer 20 can be combined or bonded with each other by a diffusion bonding process.

[0038] In detail, the first conductive layer 10 and the second conductive layer 20 can be pressed together by pressure, and then heated to a temperature below the melting point of the first conductive layer 10 and the second conductive layer 20. In this case, the atoms of the first conductive layer 10 and the second conductive layer 20 can diffuse into each other at the interface between the first conductive layer 10 and the second conductive layer 20 (i.e., on the contact surface), thereby combining or assembling into a composite conductive layer 50 (e.g., a single composite conductive layer 50).

[0039] In a variant example embodiment, the first conductive layer 10 and the second conductive layer 20 can be combined with each other via a room-temperature bonding process. In this case, each of the contact surfaces of the first conductive layer 10 and the second conductive layer 20 can be activated by an ion sputtering process or a plasma treatment process, and then can be brought into contact with each other. The activated contact surfaces of the first conductive layer 10 and the second conductive layer 20 can then be combined or bonded with each other by the inherent welding energy of the first conductive layer 10 and the second conductive layer 20. Therefore, the first conductive layer 10 and the second conductive layer 20 can be combined at room temperature to form a composite conductive layer 50.

[0040] Since the conductive substrate and the dielectric substrate can be combined or bonded to each other through a room temperature bonding process, the dielectric layer 30 and the composite conductive layer 50 can be combined to each other through a room temperature bonding process.

[0041] In another variant embodiment, the first conductive layer 10 and the second conductive layer 20 can be adhered to each other using an adhesive. Similarly, the composite conductive layer 50 and the dielectric layer 30 can be adhered to each other using an adhesive. Specifically, the adhesive can have good thermal transfer properties so that heat can be sufficiently and effectively transferred between the first conductive layer 10, the second conductive layer 20, and the dielectric layer 30 in the focusing ring 90 during plasma processing. In this case, the thickness and dielectric constant of the adhesive can be determined in such a way that phase loss of the high-frequency power is minimized whenever high-frequency power is transmitted through the adhesive.

[0042] Figure 3 It is shown Figure 2 The view shows a modified construction of the focusing ring. Except for the location of dielectric layer 30, Figure 3 The modified focusing ring in the middle can have the same characteristics as Figure 2 The focusing ring 90 shown has a basically the same construction. Therefore, in Figure 3 In the figures, the same reference numerals indicate the same as... Figure 2 The elements in this text are the same as those in the previous text, and any further detailed description of the same elements will be omitted below.

[0043] Reference Figure 3In the modified focusing ring 91, the dielectric layer 30 can be disposed on the composite conductive layer 50, that is, the second conductive layer 20 can be located between the dielectric layer 30 and the first conductive layer 10. Therefore, during the plasma processing, the plasma can directly contact the dielectric layer 30.

[0044] Specifically, the modified focusing ring 91 may include a composite conductive layer 50 and a dielectric layer 30 on the composite conductive layer 50. Therefore, the first conductive layer 10, the second conductive layer 20, and the dielectric layer 30 may be sequentially stacked on top of each other in the modified focusing ring 91.

[0045] When heat resistance rather than etch resistance is required during plasma processing, the second conductive layer 20, including silicon carbide (SiC), is exposed to the plasma space, as in... Figure 2 As disclosed in the focusing ring 90 shown. Conversely, when etch resistance is required rather than heat resistance during plasma processing, the dielectric layer 30 (e.g., comprising quartz or alumina (Al2O3)) is exposed to the plasma space, as in Figure 3 The modified focusing ring 91 shown is disclosed.

[0046] The thickness and material of the dielectric layer 30 can vary depending on the capacitance and etch resistance of the etching plasma in the plasma processing. For example, when performing a plasma etching process using chlorine (Cl2) gas or hydrogen bromide (HBr) gas as the source gas, the dielectric layer 30 may include quartz due to the low cost and good processability of quartz.

[0047] According to an example embodiment of the focusing ring, the attenuation of the transmitted power signal through the substrate W can be substantially the same as the attenuation of the transmitted power signal through the focusing ring 90 or a modified focusing ring 91, such that the intensity of the electric field caused by the transmitted power signal can be uniform from the substrate W to the focusing ring. Therefore, the plasma density can also be substantially uniform from the central portion C to the peripheral portion E of the substrate W, and plasma etching can be performed uniformly across the entire surface of the substrate W.

[0048] Figure 4 This illustrates the inclusion of, according to an example embodiment. Figure 1 and Figure 2 A structural diagram of the chuck assembly of the focusing ring 90. Although Figure 4 A chuck assembly including a focusing ring 90 is shown, but the chuck assembly can utilize... Figure 3 The focusing ring 91 is constructed in a similar manner.

[0049] Reference Figure 4The chuck assembly 500 according to an example embodiment may include a chuck dielectric plate 100, a chuck body 200, a focusing ring 90, and an insulating plate 400. The chuck dielectric plate 100 includes a first dielectric material, and a substrate W can be fixed to the chuck dielectric plate 100. The chuck body 200 supports the chuck dielectric plate 100 and includes a chuck conductive material to which at least one high-frequency power can be applied. The focusing ring 90 is disposed on the peripheral portion of the chuck body 200 and surrounds the substrate W. The insulating plate 400 supports the chuck body 200. As previously referenced... Figure 1 and Figure 2 As described, the focusing ring 90 may include a composite conductive layer 50 and a dielectric layer 30, the composite conductive layer 50 being configured as a multilayer structure with different resistances, and the dielectric layer 30 being located on at least one of the upper surface 51 and the lower surface 52 of the composite conductive layer 50.

[0050] For example, the chuck dielectric plate 100 may include a dielectric block disk that can be adhered to the chuck body 200 by an adhesive. The chuck dielectric plate 100 may include ceramic materials such as alumina (Al2O3), aluminum nitride (AlN), and yttrium oxide (Y2O3).

[0051] The substrate W can be fixed to the chuck dielectric plate 100, and the substrate W can be subjected to plasma processing processes, such as plasma etching. For example, the substrate W can include a silicon wafer or a glass substrate, on which a fine patterned structure for semiconductor devices will be formed, and on which a fine patterned structure for flat panel displays will be formed.

[0052] The chuck dielectric plate 100 may be provided with at least a fixing member SM, so that the substrate W can be fixed to the chuck dielectric plate 100 by using the fixing member SM. For example, the fixing member SM may include a fixing electrode that can be arranged in the chuck dielectric plate 100 and connected to an external DC power supply DS. For example, the fixing member SM may be a fixing electrode. Electrostatic force can be generated from the electrode, and the substrate W can be fixed to the chuck dielectric plate 100 by the electrostatic force. Therefore, the chuck assembly 500 can be configured as an electrostatic chuck (ESC) structure. The fixing electrode may be formed into one of annular shape, semi-circular shape, and a combination of at least two semi-circular shapes.

[0053] The fixing member SM may also include a mechanical joint for engaging the substrate W to the chuck dielectric plate 100 using friction. In this example embodiment, the mechanical joint may include a clamp, and the chuck assembly 500 may be configured as a friction chuck structure.

[0054] Heating electrodes can also be provided in the chuck dielectric plate 100 to heat the substrate W to a predetermined temperature during the plasma etching process. Joule heating can be generated from the heating electrodes, and the substrate W can be heated by Joule heating. The heating electrodes can be shaped as concentric circles or spirals relative to the center point of the disk-shaped chuck dielectric plate 100.

[0055] The chuck body 200 can be formed as a block-shaped disk to support the disk-shaped chuck dielectric plate 100, and can include conductive materials such as aluminum (Al), titanium (Ti), tungsten (W), stainless steel, and combinations thereof. The construction of the chuck body 200 can vary depending on the requirements of the chuck assembly 500 and the construction of the plasma processing equipment having the chuck assembly 500.

[0056] In detail, the chuck body 200 may have a stepped portion 201 constructed such that the central portion protrudes higher than the peripheral portion. Therefore, the protruding portion 202 of the chuck body 200 may be the portion of the chuck body 200 that protrudes above the peripheral portion to define the central portion of the stepped portion 201 in the periphery of the protruding portion 202 (e.g., around the protruding portion 202). The protruding portion 202 may contact the chuck dielectric plate 100 (e.g., the bottom of the chuck dielectric plate 100), and the stepped portion 201 of the chuck body 200 may contact the focusing ring 90 (e.g., the bottom of the focusing ring 90).

[0057] When high-frequency power is applied to the chuck body 200, the high-frequency power can be transmitted through the substrate W and the focusing ring 90 to the plasma space above the substrate W. Therefore, during the plasma processing, plasma can be generated in the plasma space and directed toward the substrate W. The high-frequency power may include a first power HF1 for generating the plasma and a second power HF2 for guiding the plasma to the substrate W.

[0058] The first power source HF1 may include an alternating current (AC) power supply with a frequency of about 10 MHz to about 100 MHz, and may supply sufficient energy to convert the source gas in the plasma space above the substrate W into plasma. In this example embodiment, the first power source HF1 may include radio frequency (RF) power with a frequency of about 13.56 MHz. The second power source HF2 may include an alternating current (AC) power supply with a frequency higher than about 1 MHz and lower than about 10 MHz, and may accelerate charged particles of the plasma toward the substrate W. Therefore, a plasma processing process can be performed on the substrate W.

[0059] The high-frequency power applied to the chuck body 200 can be transmitted as a first power signal TS1 through the protrusion 202 of the chuck body 200 and the substrate W, and can also be transmitted as a second power signal TS2 through the focusing ring 90 having a composite conductive layer 50 and a dielectric layer 30. The first power signal TS1 can generate plasma on the central portion C of the substrate W, and the second power signal TS2 can generate plasma on the peripheral portion E of the substrate W.

[0060] Therefore, the chuck dielectric plate 100 and the substrate W can be used as a first transmission line (e.g., a transmission path) for transmitting the first transmission power signal TS1 from the chuck body 200. The dielectric layer 30 and the composite conductive layer 50 of the focusing ring 90 can be used as a second transmission line (e.g., a transmission path) for transmitting the second transmission power signal TS2 from the chuck body 200. See below for reference respectively. Figure 6A and Figure 6B The first transmission line and the second transmission line, as shown and described in more detail, may be referred to as the first transmission line TL1 and the second transmission line TL2.

[0061] like Figure 6A and Figure 6B As shown, because each of the first transmission line TL1 (e.g., the transmission path) and the second transmission line TL2 (e.g., the transmission path) can be configured as a stacked structure of dielectric and conductive materials, the applied high-frequency power can be transmitted to the plasma space via a resistor-capacitor (RC) circuit. Therefore, the applied high-frequency power can attenuate in relation to the attenuation coefficient of each of the transmission lines TL1 and TL2 (e.g., the transmission paths), and the first transmitted power signal TS1 and the second transmitted power signal TS2 can have different energies on the substrate W and the focusing ring 90, respectively.

[0062] Given the erosion during plasma processing, the focusing ring 90 can be configured to be higher than the substrate W. For example, as... Figure 4 As shown, the upper surface 51 of the focusing ring 90 (e.g., the uppermost surface of the second conductive layer 20) may be higher than the upper surface of the substrate W relative to the bottom of the chuck body 200. Therefore, the length of the second transmission line TL2 (i.e., the total thickness (or height) of the stacked structure of the dielectric layer 30 and the composite conductive layer 50) will be longer than the length of the first transmission line TL1 (i.e., the total thickness (or height) of the stacked structure of the chuck dielectric plate 100 and the substrate W). Consequently, high-frequency power will attenuate significantly more through the second transmission line TL2 than through the first transmission line TL1, and the strength of the second transmitted power signal TS2 will be less than the strength of the first transmitted power signal TS1. As a result, the plasma density on the focusing ring 90 will be less than the plasma density on the substrate W.

[0063] The focusing ring 90 may include a dielectric layer 30 and a composite conductive layer 50, wherein a first conductive layer 10 and a second conductive layer 20 with different specific resistances may be disposed in the composite conductive layer 50. Therefore, the attenuation through the second transmission line TL2 can be varied by the construction and properties of the dielectric layer 30 and the composite conductive layer 50. Thus, by changing the construction and properties of the focusing ring 90, the strength of the second transmitted power signal TS2 can be made close to the strength of the first transmitted power signal TS1, and the strength difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized by controlling the construction and properties of the focusing ring 90. Note that the dielectric layer 30 of the focusing ring 90 may be referred to as the ring dielectric layer for comparison with the chuck dielectric plate 100.

[0064] When alternating current is applied to an RC circuit, energy loss occurs in the RC circuit relative to transmission losses caused by the resistance of the RC circuit and time delays caused by the resistance and capacitance of the RC circuit. Transmission losses are typically detected as conductor losses at the surface area of ​​the resistor in the RC circuit, and time delays can be detected as phase differences at the resistor and capacitor in the RC circuit.

[0065] In this example embodiment, the ring dielectric layer 30 of the chuck dielectric plate 100 and the focusing ring 90 can be configured to have the same capacitance.

[0066] Energy loss in AC power transmission is primarily caused by conductor losses rather than phase differences, and the capacitance of the RC circuit has a greater impact on the phase difference than on the resistance of the RC circuit. Therefore, when the chuck dielectric plate 100 and the ring dielectric layer 30 have the same capacitance, the phase difference of the second transmitted power signal TS2 can be close to the phase difference of the first transmitted power signal TS1.

[0067] Therefore, the energy loss caused by the phase difference can be substantially the same between the first power signal TS1 and the second power signal TS2, and the intensity difference between the first power signal TS1 and the second power signal TS2 can be mainly determined by the conductor losses of the first transmission line TL1 and the second transmission line TL2. That is, by experimentally determining the resistance of the composite conductive layer 50 of the focusing ring 90 in such a way that the conductor loss of the second power signal TS2 can be close to the conductor loss of the first power signal TS1, the intensity difference between the first power signal TS1 and the second power signal TS2 can be minimized.

[0068] Figure 5 It is shown Figure 4 Plan view of the chuck dielectric plate 100 and the ring dielectric layer 30 of the focusing ring 90 in the chuck assembly shown.

[0069] Reference Figure 5The annular dielectric layer 30 can be disposed on the stepped portion 201 of the chuck body 200 and can be formed into a ring surrounding the chuck dielectric plate 100. Therefore, when the gap between the annular dielectric layer 30 and the chuck dielectric plate 100 is negligible, the chuck dielectric plate 100 can have a chuck radius r. c Furthermore, the ring dielectric layer 30 may have a ring radius r3.

[0070] When the chuck dielectric plate 100 has a chuck thickness t c 0.05 chuck dielectric constant ε c and surface area A c When the ring dielectric layer 30 has a third thickness t3, a ring dielectric constant ε3, and a ring surface area A3, the capacitances of the chuck dielectric plate 100 and the ring dielectric layer 30 can be obtained according to the following equations (1) and (2), respectively. In the following equations (1) and (2), C c C1 represents the capacitance of the cassette dielectric plate 100, and C2 represents the capacitance of the ring dielectric layer 30.

[0071]

[0072]

[0073] Accordingly, the third thickness t3 of the ring dielectric layer 30 can make the capacitance C3 of the ring dielectric layer 30 compatible with the capacitance C of the chuck dielectric plate 100. c The same method is obtained through the following equation (3).

[0074]

[0075] Specifically, when the chuck dielectric plate 100 and the ring dielectric layer 30 comprise the same dielectric material, the third thickness t3 of the ring dielectric layer 30 may be less than the thickness of the chuck dielectric plate 100. For example, the ring dielectric layer 30 may comprise any one of alumina (Al2O3), quartz, yttrium oxide (Y2O3), and combinations thereof.

[0076] Figure 6A This is a perspective view showing the first transmission line (e.g., transmission path) TL1 in which the chuck dielectric plate 100 and the substrate W are stacked. Figure 6B This is a perspective view showing a second transmission line (e.g., transmission path) TL2 in which a ring dielectric layer 30 and a composite conductive layer 50 are stacked.

[0077] Reference Figure 4 , Figure 6A and Figure 6BHigh-frequency electricity can be applied to the chuck body 200 and transmitted to the plasma space above the substrate W via a first transmission line TL1 located at the central portion C of the chuck body 200 and a second transmission line TL2 located at the peripheral portion E of the chuck body 200. Therefore, the high-frequency electricity can be converted into a first transmitted power signal TS1 on the substrate W and into a second transmitted power signal TS2 on the focusing ring 90.

[0078] In this case, the strength of the first transmitted power signal TS1 on the substrate W can be obtained according to the following equation (4). The strength of the second transmitted power signal TS1 on the focusing ring 90 can be obtained according to the following equation (5).

[0079]

[0080]

[0081] In equations (4) and (5) above, z is the position along the height direction of the chuck assembly 500, x is the position along the radial direction of the chuck assembly 500, t is any time after the high-frequency power HF1 is applied to the chuck body 200, ω is the angular velocity of the high-frequency power HF1, S1 and S2 are the first intensity and the second intensity, respectively, α1 and α2 are the attenuation coefficients of the first transmission line TL1 and the second transmission line TL2, respectively, and β1 and β2 are the phase coefficients of the first transmission line TL1 and the second transmission line TL2, respectively. Any internal position of the transmission line can be determined by the coordinate in the radial direction x, such that the position of the skin depth of the transmission line can be determined by the x-coordinate value. For example, S0 represents the initial intensity of the high-frequency power HF1 at the moment when the high-frequency power HF1 is applied to the chuck body 200, and S... 1x This represents the arbitrary strength of the first transmitted power signal TS1 at any time and any radial position x on the first transmission line TL1. Similarly, S... 2x The value represents the arbitrary strength of the second transmitted power signal TS2 at any time and any radial position x of the second transmission line TL2.

[0082] Although the transmission loss of high-frequency power HF1 occurs along the radial direction x and the height direction z of the chuck assembly 500, the transmission loss along the radial direction x does not affect the generation of plasma on the substrate W. Therefore, in order to minimize the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2, the transmission loss along the radial direction x can be ignored.

[0083] Therefore, the strength of the first transmitted power signal TS1 can be mainly determined by the attenuation coefficient α1 of the first transmission line TL1. The strength of the second transmitted power signal TS2 can be mainly determined by the attenuation coefficient α2 of the second transmission line TL2.

[0084] Therefore, when the attenuation coefficient α1 of the first transmission line TL1 is essentially the same as the attenuation coefficient α2 of the second transmission line TL2, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized. As a result, the uniformity of plasma density in the plasma space can be increased.

[0085] The attenuation coefficient α is usually expressed as the following equation (6). In equation (6), B is a constant determined by the dielectric constant and permeability of the transmission line, f is the frequency of the high-frequency power transmitted through the transmission line, ω is the angular velocity of the high-frequency power, and ρ is the specific resistance of the transmission line.

[0086]

[0087] In this example embodiment, since the same high-frequency power can be applied to the first transmission line TL1 and the second transmission line TL2, the angular velocity of the high-frequency power can be the same in the first transmission line TL1 and the second transmission line TL2. Therefore, the attenuation coefficients α1 and α2 of the first transmission line TL1 and the second transmission line TL2 can be inversely proportional to the square root of the specific resistance ρ of the respective transmission lines.

[0088] Therefore, when the composite conductive layer 50 of the focusing ring 90 has a sufficiently large specific resistance, the attenuation coefficient α2 of the second transmission line TL2 can be sufficiently reduced. Consequently, the strength of the second transmitted power signal TS2 can approach the strength of the first transmitted power signal TS1.

[0089] The focusing ring 90 can be formed as a ring disposed on the stepped portion 201 of the chuck body 200 and surrounding the base W with a thickness greater than that of the base W. This makes it difficult for the focusing ring 90 to have a uniform resistivity along the entire body. For this reason, the conductive material of the focusing ring 90 can be configured as a first conductive layer 10 with a relatively small thickness and a small resistivity, and a second conductive layer 20 with a relatively large thickness and a large resistivity. Therefore, the focusing ring 90 can include a composite conductive layer 50 comprising the first conductive layer 10 and the second conductive layer 20.

[0090] Because the resistivity of the first conductive layer 10 is relatively small, its attenuation coefficient α is relatively large as shown in equation (6). Therefore, when the high-frequency power HF1 is transmitted through the focusing ring 90, a relatively large amount of conductor loss may occur at the first conductive layer 10. Conversely, because the resistivity of the second conductive layer 20 is relatively large, its attenuation coefficient α is relatively small as shown in equation (6). Therefore, when the high-frequency power HF1 is transmitted through the focusing ring 90, a relatively small amount of conductor loss may occur at the second conductive layer 20. Specifically, the second conductive layer 20 may have a structure in which attenuation essentially does not occur at the second conductive layer 20.

[0091] Therefore, the attenuation of the high-frequency power HF1 at the chuck dielectric plate 100 and the ring dielectric layer 30 can be negligible, and most of the attenuation of the high-frequency power HF1 can occur at the substrate W and the first conductive layer 10 of the focusing ring 90. When the high-frequency power HF1 is transmitted through the chuck assembly 500 in the height direction z, the total attenuation of the high-frequency power HF1 at the substrate W can be obtained by the following equation (7), and the total attenuation of the high-frequency power HF1 at the first conductive layer 10 can be obtained by the following equation (8).

[0092]

[0093]

[0094] Therefore, the first thickness t1 of the first conductive layer 10 can be determined in such a way that the total attenuation of the high-frequency power HF1 at the substrate W can be as close as possible to the total attenuation of the high-frequency power HF1 at the first conductive layer 10, as expressed in equation (9).

[0095]

[0096] Therefore, when the conductive material of the first conductive layer 10 is selected and the specific resistance of the first conductive layer 10 is thus determined, the first thickness t1 of the first conductive layer 10 can be obtained by the above equation (9). That is, when the first thickness t1 of the first conductive layer 10 satisfies equation (9), the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 on the substrate W and the focusing ring 90 can be minimized.

[0097] In this configuration, the second conductive layer 20 can have a higher resistivity than the first conductive layer 10, such that attenuation essentially does not occur within the second conductive layer 20. For example, the resistivity of the second conductive layer 20 can be approximately 10 to approximately 100 times that of the first conductive layer 10. Therefore, the strength of the second transmitted power signal TS2 can be substantially the same as the strength of the high-frequency power HF1 transmitted through the first conductive layer 10.

[0098] Since the third thickness t3 of the ring dielectric layer 30 can be obtained by equation (3), and the first thickness t1 of the first conductive layer 10 can be obtained by equation (9), the second thickness t2 of the second conductive layer 20 can be obtained as the difference between the total thickness T of the focusing ring 90 and the sum of the first thickness t1 and the third thickness t3, as described in equation (10) below. The total thickness T of the focusing ring 90 can be set to the specifications of the chuck assembly 500 according to the requirements of the plasma processing process and the chamber characteristics of the plasma processing equipment with the chuck assembly 500.

[0099] t2=T-(t1+t3) (10)

[0100] In this example embodiment, the substrate W may include a silicon wafer, and the first conductive layer 10 may include silicon (Si), such that the first conductive layer 10 may have the same thickness as the substrate W. Furthermore, the second conductive layer 20 may include a high-resistance conductive material, such as silicon carbide (SiC), and the total thickness T of the focusing ring 90 may be in the range of approximately 3 mm to approximately 6 mm.

[0101] The first thickness t1 obtained from equation (9) is based on the following assumption: the transmission loss along the radial direction x of the second transmission line TL2 and the phase difference caused by the resistance are negligible, so that the strength of the second transmission power signal TS2 will deviate slightly from the actual strength of the second transmission power signal TS2.

[0102] Therefore, the first thickness t1 and the first specific resistance ρ1 of the first conductive layer 10 can be experimentally obtained through simulation based on equations (4) and (5). Thus, the strength of the second transmitted power signal TS2 can become closer to the strength of the first transmitted power signal TS1, thereby more accurately minimizing the strength difference between the first transmitted power signal TS1 and the second transmitted power signal TS2.

[0103] Figure 7 This is a graph showing the relationship between the resistivity of the first conductive layer 10 of the focusing ring 90 and the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 for various thicknesses of the first conductive layer 10. Figure 7 In this simulation, the change in intensity difference is shown based on the change in the specific resistance of the first conductive layer 10 with a specific first thickness t1, and multiple first conductive layers 10 with different specific resistances are provided for simulation to detect the relationship between specific resistance and intensity difference. Assuming that the first conductive layer 10 is made of a material with the same permeability and dielectric constant, three simulations are performed for three first conductive layers 10 with first thickness t1 set to approximately 2 mm, 3 mm, and 4 mm, respectively.

[0104] like Figure 7As shown, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 is minimized at specific points in the resistivity of each of the first conductive layers 10. When the first thickness t1 of the first conductive layer 10 is approximately 2 mm, the intensity difference is minimized at the first minimum point MP1, and when the first thickness t1 of the first conductive layer 10 is approximately 3 mm, the intensity difference is minimized at the second minimum point MP2. Similarly, when the first thickness t1 of the first conductive layer 10 is approximately 4 mm, the intensity difference is minimized at the third minimum point MP3. Of the three minimum points MP1, MP2, and MP3, the intensity difference is minimized when the first thickness t1 is approximately 2 mm.

[0105] therefore, Figure 7 Simulation results show that both resistivity and thickness are achieved at the minimum point where the intensity difference is minimized. Hereinafter, the resistivity and thickness at the minimum point where the intensity difference is minimized are referred to as minimum resistivity and minimum thickness. Therefore, when the first conductive layer 10 can be configured to have minimum resistivity and minimum thickness as the first resistivity ρ1 and the first thickness t1, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized over the substrate W and the focusing ring 90. In this example embodiment, when the first conductive layer 10 has a first thickness t1 of approximately 2 mm and a first resistivity ρ1 of approximately 25 Ωcm, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized.

[0106] Based on the above simulation, the strengths of the first transmitted power signal TS1 and the second transmitted power signal TS2 can be calculated separately using a computer system, and the arithmetic difference between the strengths can be obtained for each specific resistance. Therefore, in Figure 7 The results of the computer simulation shown reflect the transmission loss in the radial direction and the phase difference caused by the resistance, which can be ignored for the sake of the validity of equation (9).

[0107] Therefore, the first thickness t1 and first specific resistance ρ1 of the first conductive layer 10 determined by computer simulation can reduce the intensity difference more than the first thickness t1 and first specific resistance ρ1 of the first conductive layer 10 calculated by equation (9).

[0108] The third thickness t3 of the ring dielectric layer 30 can be obtained by equation (3), and the first thickness t1 of the first conductive layer 10 can be obtained by equation (3). Figure 7 The simulation results shown in the figure indicate that the second thickness t2 of the second conductive layer 20 can be determined by equation (10).

[0109] For example, an insulating plate 400 can be disposed below and support the chuck body 200. The insulating plate 400 may have a surface area corresponding to the chuck body 200, such that the chuck body 200 can be supported by the insulating plate 400 (e.g., completely supported by the insulating plate 400). Therefore, the chuck body 200 can be sufficiently insulated from the ground plane via the insulating plate 400, which can be disposed at the lower part of the chuck assembly 500. Specifically, the insulating plate 400 can be constructed with a shape and material that minimizes the capacitance between the chuck body 200 and the insulating plate 400.

[0110] The insulating plate 400 may comprise a single insulator or a multilayer structure having at least two insulating layers with different dielectric constants. Therefore, leakage current through the insulating plate 400 can be adequately prevented, and the plasma density does not deteriorate over time.

[0111] A shielding ring SR extends from the insulating plate 400 in a configuration such that the side surfaces of the chuck body 200 and the focusing ring 90 are surrounded by the shielding ring SR. The shielding ring SR can have a sufficiently high dielectric constant to create sufficient impedance between the chuck body 200 and the shielding ring SR, thereby preventing high-frequency power HF1 from being lost to the sides of the chuck assembly 500. For example, the shielding ring SR can comprise a dielectric material with a dielectric constant of less than about 5, such as quartz, silicon carbide (SiC), and silicon oxide (SiO2).

[0112] Furthermore, since the shielding ring SR can surround the chuck body 200 and the focusing ring 90, it can effectively prevent the chuck body 200 and the focusing ring 90 from being damaged by plasma, residual source gas, and various particles from the plasma processing process.

[0113] The ground plane can also be arranged below the insulating plate 400. The ground plane can be shaped to be the same as the insulating plate 400, such that the ground plane can be covered by the insulating plate 400 (e.g., completely covered by the insulating plate 400). High-frequency power HF1 can be applied to the chuck body 200 via power lines penetrating the ground plane.

[0114] Although this example embodiment discloses that the ring dielectric layer 30 can be disposed below the first conductive layer 10, the ring dielectric layer 30 can also be disposed as described in reference 10, depending on the requirements of the plasma processing process. Figure 3 The arrangement is described in detail on the second conductive layer 20.

[0115] According to an example embodiment of the chuck assembly 500, the first thickness t1 and the first specific resistance ρ1 of the first conductive layer 10 of the focusing ring 90 can be obtained through theoretical calculation or computer simulation in such a way that the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized. Therefore, when a plasma etching process can be performed on the substrate W, the density of the plasma on the substrate W can be sufficiently uniform throughout the substrate W, thereby improving the etching uniformity of the substrate W from the central portion to the peripheral portion.

[0116] Figure 8 This illustrates a method according to an example embodiment with... Figure 4 The structural diagram of the plasma processing equipment with chuck assembly 500.

[0117] Reference Figure 8 The plasma processing apparatus 1000 according to an example embodiment may include a processing chamber 600, a source supplier 700, a chuck assembly 500, and a power supply 800. The processing chamber 600 has a processing space PS in which plasma processing processes can be performed. The source supplier 700 is disposed at the upper part of the processing chamber 600 and supplies source gas G for the plasma processing processes. The chuck assembly 500 is disposed at the lower part of the processing chamber 600 and holds the substrate W to be processed by the plasma processing processes. The power supply 800 applies at least one high-frequency power to the chuck assembly 500 and generates plasma for the plasma processing processes in the processing space PS. Hereinafter, because the plasma for the plasma processing processes is generated in the processing space above the substrate W, the processing space PS of the processing chamber 600 may generally be referred to as the plasma space.

[0118] The chuck assembly 500 of the plasma processing device 1000 may have the same characteristics as the reference. Figures 4 to 7 The structures described in detail are basically the same. Therefore, in Figure 8 In the figures, the same reference numerals indicate the same as... Figures 4 to 7 The elements in this text are the same as those in the previous text, and any further detailed description of the same elements will be omitted below.

[0119] Reference Figure 8 The processing chamber 600 may include a three-dimensional structure having a processing space PS therein, and has sufficient strength and rigidity for plasma processing. In this example embodiment, the processing chamber 600 may include a bottom 601, a top plate 602 opposite to the bottom 601, and a plurality of sidewalls 603 between the bottom 601 and the top plate 602.

[0120] A door 610 can be provided in one of the sidewalls 603, through which the substrate W can be loaded into or unloaded from the processing chamber 600. A chuck assembly 500 can be arranged on the bottom 601 of the processing chamber 600, and the substrate W can be fixed to the chuck assembly 500.

[0121] Specifically, the chuck assembly 500 can be arranged on the central portion of the bottom 601 of the processing chamber 600, and multiple exhaust ports DH can be arranged around the chuck assembly 500 to pass through the bottom 601. Residual gases and byproducts of the plasma processing can be discharged from the processing chamber 600 through the exhaust ports DH.

[0122] A collection chamber 900 may be disposed below the processing chamber 600 and communicate with the processing chamber 600 via an exhaust port DH, allowing residual gases and byproducts of the plasma processing process to be collected in the collection chamber 900. A pump structure 910 may be disposed in the lower or side portion of the collection chamber 900 and may force residual gases and byproducts of the plasma processing process to be discharged from the processing chamber 600. In this example embodiment, the pump structure 910 may include a flow control valve V and a vacuum pump P.

[0123] While this example embodiment discloses a processing chamber 600 configured as an entire housing with a single door 610 for loading and unloading the substrate W, other configurations may be incorporated into the processing chamber depending on the characteristics of the plasma processing apparatus. For example, the processing chamber 600 may include a lower housing and an upper housing that can be combined with each other. Thus, when the substrate W is loaded into or unloaded from the processing chamber 600, the lower housing and the upper housing can be separated from each other, and the processing space PS can be exposed to the surrounding environment. Conversely, when a plasma processing process is performed in the processing chamber 600, the upper housing and the lower housing can be combined with each other in a configuration such that the processing space PS can be separated from the surrounding environment.

[0124] In this example embodiment, the plasma processing process may include a plasma etching process, in which the source gas can be transformed into plasma in the processing space PS by plasma etching, and the substrate can be etched using plasma. However, any other plasma processing process can be performed in the plasma processing apparatus 1000, as long as the focusing ring is arranged around the substrate W and high-frequency power is applied to the chuck assembly 500 to generate plasma in the processing space PS of the processing chamber 600.

[0125] For example, the source supply 700 may be located above the chuck assembly 500 in the processing chamber 600. The source supply 700 may include a gas supply 710, a source line 720, and a source tank 730. The gas supply 710 supplies source gas G to the processing space PS through multiple supply holes SH, the source line 720 transfers source gas G to the gas supply 710, and the source tank 730 is located outside the processing chamber 600 and connected to the source line 720.

[0126] The gas supply unit 710 can be formed into a cubic structure with dimensions larger than the substrate W, such that the substrate W can be fully covered by the gas supply unit 710. The upper part of the gas supply unit 710 can be connected to the source line 720, and multiple supply holes SH can be arranged at the lower part of the gas supply unit 710 facing the processing space PS. Therefore, the source gas G can be transferred to the gas supply unit 710 through the source line 720 and can be uniformly supplied to the processing space PS through the multiple supply holes SH. In this example embodiment, the gas supply unit 710 may include a nozzle with dimensions sufficient to fully cover the substrate W.

[0127] The source gas G can be varied according to the characteristics and requirements of the plasma processing technology. For example, the source gas G may include chlorine fluoride (Cl). x F y ), chlorine (Cl2) gas, hydrogen bromide (HBr), etc.

[0128] A chuck assembly 500 can be disposed on the bottom of a processing chamber 600, and a substrate W can be fixed to the chuck assembly 500. Therefore, a processing space PS can be disposed between the substrate W and a gas supplier 710. A source gas G can be supplied to the processing space PS and converted into plasma on the substrate W for use in a plasma processing process within the processing space PS, allowing the processing space PS to function as a plasma space in which plasma can be generated. A first high-frequency power HF1 can be applied to the chuck assembly 500 to generate plasma, and a second high-frequency power HF2 can be applied to the chuck assembly 500 to guide the plasma onto the substrate W.

[0129] The chuck assembly 500 may include a composite conductive layer 50 and a ring dielectric layer 30 located on or below the composite conductive layer 50. The composite conductive layer 50 may include a first conductive layer 10 having a relatively small thickness and a relatively small resistivity, and a second conductive layer 20 having a relatively large thickness and a relatively large resistivity.

[0130] A first high-frequency power HF1 can be transmitted to the processing space PS or plasma space as a first transmitted power signal TS1 via a first transmission line TL1 including a chuck dielectric plate 100 and a substrate W, and transmitted to the processing space PS or plasma space as a second transmitted power signal TS2 via a second transmission line TL2 including a focusing ring 90. In this case, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized by controlling the thickness and specific resistance of the first conductive layer 10 of the focusing ring 90.

[0131] Since the intensity difference can be minimized over the substrate W, the plasma density can be uniform from the center to the periphery of the substrate W, thus greatly increasing the plasma homogeneity throughout the substrate W.

[0132] The power supply 800 can be located outside the processing chamber 600 and can be connected to the chuck body 200 of the chuck assembly 500. For example, the power supply 800 may include a first power supply 810, a second power supply 820, and a third power supply 830. The first power supply 810 is used to generate a first high-frequency power HF1 and apply the first high-frequency power HF1 to the chuck body 200 to change the source gas in the processing space PS into plasma for plasma processing. The second power supply 820 is used to generate a second high-frequency power HF2 and apply the second high-frequency power HF2 to the chuck body 200 to guide charged particles of plasma onto the substrate W in the processing space PS. The third power supply 830 is used to generate direct current (DC) power and apply the DC power to the fixing electrodes in the chuck dielectric plate 100 to fix the substrate W to the chuck dielectric plate 100.

[0133] The first power supply 810 may include a first AC generator 811 and a first impedance matching device 813. The first AC generator 811 may generate a first high-frequency power HF1, and the first impedance matching device 813 may include a transformer and a plurality of matching circuits for synchronizing the impedance between the first AC generator 811 and the chuck body 200.

[0134] The first high-frequency power HF1 may include alternating current with a frequency of about 10 MHz to about 100 MHz, and can be transmitted to the processing space PS via the first transmission line TL1 as a first transmitted power signal TS1, and transmitted to the processing space PS via the second transmission line TL2 as a second transmitted power signal TS2. In this example embodiment, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized by controlling the thickness and dielectric constant of the ring dielectric layer 30 and the thickness and specific resistance of the first conductive layer 10.

[0135] The source gas G can be transformed into active ions and free radicals in the processing space PS by a first transmission power signal TS1 and a second transmission power signal TS2, thereby generating plasma for plasma processing in the processing space PS by the first transmission power signal TS1 and the second transmission power signal TS2. In this example embodiment, the plasma may include etch plasma for patterning or etching thin layers on a substrate W.

[0136] The second power supply 820 may include a second AC generator 821 and a second impedance matching device 823. The second AC generator 821 may generate a second high-frequency power HF2, and the second impedance matching device 823 may include a transformer and a plurality of matching circuits for synchronizing the impedance between the second AC generator 821 and the chuck body 200.

[0137] Specifically, the frequency of the second high-frequency power HF2 can be approximately 0.01 to approximately 0.1 times the frequency of the first high-frequency power HF1. ​​Therefore, the second high-frequency power HF2 can include alternating current with a frequency of approximately 1 MHz to approximately 10 MHz. Active ions and free radicals of the plasma can be accelerated onto the substrate W by the second high-frequency power HF2, and the substrate W can be subjected to plasma processing.

[0138] Since the attenuation coefficient, as shown in equation (6), is proportional to the square root of the frequency, and the frequency of the second high-frequency power HF2 can be approximately 0.01 to approximately 0.1 times the frequency of the first high-frequency power HF1, the attenuation of the second high-frequency power HF2 is negligible compared to the attenuation of the first high-frequency power HF1. ​​Therefore, the second high-frequency power HF2 can be uniformly transmitted to the processing space PS, and thus the active ions and free radicals of the plasma can be uniformly accelerated onto the substrate W from the central portion C to the peripheral portion E.

[0139] The third power supply 830 can apply DC power to the fixed electrodes in the chuck dielectric plate 100. Electrostatic force can be generated from the fixed electrodes, and the substrate W can be fixed to the chuck dielectric plate 100 of the chuck assembly 500.

[0140] According to this exemplary embodiment of the plasma processing apparatus, by controlling the dielectric constant and thickness of the ring dielectric layer 30 and the thickness and specific resistance of the first conductive layer 10 of the focusing ring 90, the transmission loss of the second transmitted power signal TS2 can be made close to the transmission loss of the first transmitted power signal TS1. Therefore, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized in the plasma processing apparatus 1000, thereby improving the uniformity of the plasma processing on the substrate W.

[0141] According to an example embodiment, focusing rings 90 and 91 for focusing plasma onto a substrate W may include a composite conductive layer 50 and a dielectric layer 30, wherein the composite conductive layer 50 includes a first conductive layer 10 having a relatively small thickness and a relatively small resistivity, and a second conductive layer 20 having a relatively large thickness and a relatively large resistivity. The dielectric layer 30 may have a thickness and dielectric constant such that its capacitance is substantially the same as that of the chuck dielectric plate to which the substrate is fixed. The first conductive layer of the focusing ring may have a thickness and resistivity such that the attenuation of the second transmitted power signal transmitted through the focusing ring is close to the attenuation of the first transmitted power signal transmitted through the chuck dielectric plate and the substrate. The second conductive layer of the focusing ring may have a resistivity so large that transmission loss does not occur when high-frequency power can be transmitted through the second conductive layer.

[0142] Therefore, the intensity difference between the first transmitted power signal TS1 and the second transmitted power signal TS2 can be minimized in the plasma processing apparatus 1000, thereby improving the uniformity of the plasma processing on the substrate W. Specifically, when performing a plasma processing on a large-diameter substrate W (e.g., a wafer), the plasma density difference is significant between the central portion C and the peripheral portion E of the substrate W. However, according to this example embodiment of the chuck assembly and the plasma processing apparatus, the plasma density can become sufficiently uniform from the central portion C to the peripheral portion E of the substrate W.

[0143] By summarizing and reviewing, when high-frequency power is applied to the chuck assembly and transmitted to the plasma space via the chuck and substrate, and via the focusing ring, the time delay and attenuation of the high-frequency power will differ when transmitted via the chuck and when transmitted via the focusing ring. For example, because the focusing ring is made of a different material than the substrate and chuck, and because the focusing ring is constructed with a different structure than the substrate and chuck, the time delay and attenuation of the high-frequency power will differ when transmitted via the central portion of the chuck assembly including the chuck to the substrate and when transmitted to the peripheral portion of the chuck assembly including the focusing ring.

[0144] Because the focusing ring is typically thicker than the substrate, the attenuation of the high-frequency power at the focusing ring is greater than that at the substrate, considering the erosion caused by the plasma process. Therefore, the electric field strength generated by the high-frequency power in the plasma space is much smaller around the focusing ring than around the substrate. Consequently, the plasma density is much lower above the focusing ring than above the substrate, which can cause process defects at the peripheral portion of the substrate during plasma processing.

[0145] Therefore, an improved focusing ring is needed, wherein the electric field strength difference between the substrate and the focusing ring can be minimized when high-frequency power is applied to the chuck assembly. Thus, an example embodiment provides a focusing ring comprising a composite conductive layer and a dielectric layer of high and low resistance layers stacked on top of each other, thereby minimizing the strength difference of the electric field generated by the high-frequency power between the substrate and the focusing ring. An example embodiment also provides a chuck assembly for a plasma processing process having the above-described focusing ring, and a plasma processing apparatus including the above-described chuck assembly.

[0146] Example embodiments have been disclosed herein. While specific terminology has been used, it is intended for general and descriptive purposes only and not for limiting purposes. In some instances, as will be apparent to those skilled in the art, features, characteristics, and / or elements described in connection with specific embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, as of the time of filing of this application, unless otherwise specifically indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the claims.

Claims

1. A focusing ring, the focusing ring comprising: A first conductive layer has a first thickness and a first specific resistance; A second conductive layer is stacked on the first conductive layer, and the second conductive layer has a second thickness greater than the first thickness and a second specific resistance greater than the first specific resistance. as well as A ring dielectric layer is located on one of the lower surface of the first conductive layer and the upper surface of the second conductive layer. The focusing ring is configured to be included in a chuck assembly for plasma processing. The chuck assembly further includes a chuck dielectric plate and a chuck body supporting the dielectric plate. The focusing ring is configured to be located on the peripheral portion of the chuck body. The ring dielectric layer has a thickness satisfied by the following equation (1). （1）， Where t3 represents the thickness of the ring dielectric layer, t c ε represents the thickness of the chuck dielectric plate, ε3 represents the dielectric constant of the ring dielectric layer, ε c Let r represent the dielectric constant of the chuck dielectric plate, r3 represent the radius of the ring dielectric layer at a distance from the center of the chuck body, and r c This indicates the radius of the chuck dielectric plate at the center of the chuck body.

2. The focus ring of claim 1, wherein, The second specific resistance is 10 to 100 times that of the first specific resistance.

3. The focusing ring according to claim 2, wherein, The first specific resistance is in the range of 10 cm to 100 cm.

4. The focusing ring according to claim 1, wherein, The first conductive layer comprises silicon, and the second conductive layer comprises silicon carbide.

5. A chuck assembly for fixing a substrate, the chuck assembly comprising: A chuck dielectric plate, including dielectric material, is used to support a substrate; The chuck body includes a conductive material and supports a chuck dielectric plate, such that at least one high-frequency power is applied to the chuck body. as well as A focusing ring, located on the outer periphery of the chuck body to surround the base, the focusing ring comprising: The first conductive layer has a first specific resistance. A second conductive layer is located on top of the first conductive layer. The second conductive layer has a second specific resistance different from the first specific resistance, and the first and second conductive layers are combined to form a composite conductive layer. A ring dielectric layer is located on one of the lower and upper surfaces of the composite conductive layer. The ring dielectric layer has a thickness satisfied by the following equation (1). （1）， Where t3 represents the thickness of the ring dielectric layer, t c ε represents the thickness of the chuck dielectric plate, ε3 represents the dielectric constant of the ring dielectric layer, ε c Let r represent the dielectric constant of the chuck dielectric plate, r3 represent the radius of the ring dielectric layer at a distance from the center of the chuck body, and r c This indicates the radius of the chuck dielectric plate at the center of the chuck body.

6. The chuck assembly of claim 5, wherein, The ring dielectric layer includes any one of alumina, quartz, yttrium oxide, and combinations thereof.

7. The chuck assembly of claim 6, wherein, The chuck dielectric plate comprises the same material as the ring dielectric layer.

8. The chuck assembly of claim 6, wherein, The composite conductive layer includes: The first conductive layer has a first thickness, and The second conductive layer has a second thickness greater than the first thickness, and a second resistivity greater than the first resistivity.

9. The chuck assembly of claim 8, wherein, The first thickness is greater than the thickness of the substrate and satisfies the following equation (2). （2）， Where t1 represents the first thickness of the first conductive layer, t w ρ represents the thickness of the substrate, ρ1 represents the first specific resistance of the first conductive layer, and ρ w This indicates the specific resistivity of the substrate.

10. The chuck assembly of claim 8, wherein, High-frequency power includes: A first transmitted electrical signal is transmitted through a first transmission line comprising a chuck dielectric plate and a substrate, and has a first strength satisfied by the following equation (3), and The second transmitted power signal is transmitted through a second transmission line including a focusing ring, and has a second strength satisfied by the following equation (4). （3）， （4）， Where z is the position along the height direction of the chuck assembly, x is the position along the radial direction of the chuck assembly, and t is any time after the high-frequency power is applied to the chuck body. S1 and S2 are the angular velocity of the high-frequency electric current, respectively; S0 is the initial intensity when the high-frequency electric current is applied to the chuck body; α1 and α2 are the attenuation coefficients of the first and second transmission lines, respectively. 1 and 2 are the phase coefficients of the first and second transmission lines, respectively, and The first thickness and the first specific resistance include the minimum thickness and the minimum specific resistance, which are obtained simultaneously through computer simulation of the minimum point where the difference between the first strength and the second strength is minimized.

11. The chuck assembly of claim 10, wherein, The minimum point is detected as the point where the intensity difference between the first intensity and the second intensity is the smallest in the curve of the first conductive layer. The curve indicates the relationship between the specific resistance of the first conductive layer and the intensity difference between the first intensity and the second intensity under the condition of a first thickness of the first conductive layer.

12. The chuck assembly of claim 8, wherein, The second thickness of the second conductive layer is satisfied by the following equation (5). （5）， Where t1 represents the first thickness of the first conductive layer, and T represents the total thickness of the focusing ring.

13. The chuck assembly of claim 5, wherein, The chuck dielectric plate includes at least a fixed electrode, which is stacked at the center of the chuck body.

14. The chuck assembly of claim 5, wherein, The conductive material of the chuck body includes any one of aluminum, titanium, tungsten, stainless steel, and combinations thereof.

15. A plasma treatment apparatus for performing a plasma treatment process on a substrate, the plasma treatment apparatus comprising: The processing chamber has a processing space in which plasma processing technology is carried out; A source supply unit, located at the top of the processing chamber, supplies the source gas for the plasma processing process. The chuck assembly is located at the lower part of the processing chamber to secure the base. as well as A power source, at least one type of high-frequency electrical current, is applied to the chuck assembly, and plasma for plasma processing is generated in the processing space. The chuck assembly includes: The chuck dielectric plate, including the dielectric material, is used to support the substrate. The chuck body includes a conductive material and supports a chuck dielectric plate, such that at least the high-frequency power is applied to the chuck body. A focusing ring, located on the outer periphery of the chuck body to surround the substrate, comprises: a first conductive layer having a first specific resistance; a second conductive layer located on the first conductive layer, the second conductive layer having a second specific resistance different from the first specific resistance, and the first and second conductive layers being combined to form a composite conductive layer; and a ring dielectric layer located on one of the lower and upper surfaces of the composite conductive layer. The ring dielectric layer has a thickness satisfied by the following equation (6). （6）， Where t3 represents the thickness of the ring dielectric layer, t c ε represents the thickness of the chuck dielectric plate, ε3 represents the dielectric constant of the ring dielectric layer, ε c Let r represent the dielectric constant of the chuck dielectric plate, r3 represent the radius of the ring dielectric layer at a distance from the center of the chuck body, and r c This indicates the radius of the chuck dielectric plate at the center of the chuck body.

16. The plasma processing apparatus of claim 15, wherein, The composite conductive layer includes: The first conductive layer has a first thickness, and The second conductive layer has a second thickness greater than the first thickness, and a second resistivity greater than the first resistivity.

17. The plasma processing apparatus of claim 16, wherein, The first thickness is greater than the thickness of the substrate and satisfies the following equation (7). （7）, where t1 represents the first thickness of the first conductive layer, t w represents the thickness of the substrate, p1 represents the first specific resistance of the first conductive layer, and p w represents the specific resistance of the substrate.

18. The plasma processing apparatus of claim 16, wherein, The high-frequency power signal includes: a first transmitted power signal, transmitted along a first transmission line having a chuck dielectric plate and a substrate, and having a first strength satisfied by the following equation (8); and a second transmitted power signal, transmitted along a second transmission line having a focusing ring, and having a second strength satisfied by the following equation (9). （8）， （9）， Where z is the position along the height direction of the chuck assembly, x is the position along the radial direction of the chuck assembly, and t is any time after the high-frequency power is applied to the chuck body. S1 and S2 are the angular velocity of the high-frequency electric current, respectively; S0 is the initial intensity when the high-frequency electric current is applied to the chuck body; α1 and α2 are the attenuation coefficients of the first and second transmission lines, respectively. 1 and 2 are the phase coefficients of the first and second transmission lines, respectively, and The first thickness and the first specific resistance include the minimum thickness and the minimum specific resistance, which are obtained simultaneously through computer simulation of the minimum point where the difference between the first strength and the second strength is minimized.

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