Low-frequency RF generator and associated electrostatic chuck

Abstract

A system is described having a low-frequency RF generator. The low-frequency RF has an operating frequency range of 10 kilohertz (kHz) to 330 kHz. The low-frequency RF generator generates an RF signal. The system further includes an impedance matching circuit coupled to the low-frequency RF generator to receive the RF signal. The impedance matching circuit modifies the impedance of the RF signal and outputs the modified RF signal. The system includes a plasma chamber coupled to the RF generator to receive the modified RF signal. The plasma chamber includes a chuck having a dielectric layer and a base metal layer. The dielectric layer is positioned on top of the base metal layer. The dielectric layer has a bottom surface, and the base metal layer has a top surface. The base metal layer has a porous plug, and the bottom surface of the dielectric layer has a portion in contact with the porous plug.

Description

Technical Field

[0001] This embodiment relates to a system and method for using a low-frequency radio frequency (RF) generator and an associated electrostatic chuck.

Background Art

[0002] In plasma tools, multiple radio frequency (RF) generators are used. A first RF generator is coupled to a matcher. Also, a second RF generator is coupled to the matcher. The output of the matcher is coupled to a plasma chamber. A substrate is placed within the plasma chamber.

[0003] The RF generator generates an RF signal, and the RF signal is supplied to the plasma chamber via the matcher to process the substrate. However, to generate the RF signal, a large amount of power is consumed by the RF generator. In addition, the RF generator does not facilitate the achievement of an etching rate for etching the substrate. Also, some components of the plasma chamber deteriorate over time and cause problems during substrate processing.

[0004] The embodiments described in this disclosure arise in such a situation.

[0005] The background description provided here is for the purpose of generally presenting the content of this disclosure. Within the scope described in this background art section, research by the inventors named at the present time, as well as aspects of the description that cannot be separately regarded as prior art at the time of filing, are not admitted as prior art against this disclosure, whether explicitly or implicitly.

Summary of the Invention

[0006] Embodiments of this disclosure provide systems, apparatus, methods, and computer programs for using low-frequency radio frequency (RF) generators and associated electrostatic chucks. It should be understood that these embodiments can be implemented in various ways, for example, as processes, apparatus, systems, devices, or on computer-readable media. Several embodiments are described below.

[0007] In one embodiment, a system having a low-frequency RF generator is described. The low-frequency RF has an operating frequency range of 10 kilohertz (kHz) to 330 kHz. The low-frequency RF generator generates an RF signal. The system further includes an impedance matching circuit coupled to the low-frequency RF generator to receive the RF signal. The impedance matching circuit corrects the impedance of the RF signal and outputs the corrected RF signal. The system includes a plasma chamber coupled to the RF generator to receive the corrected RF signal. The plasma chamber includes a chuck having a dielectric layer and a base metal layer. The dielectric layer is located on top of the base metal layer. The dielectric layer has a bottom surface, and the base metal layer has a top surface. The base metal layer has a porous plug, and the bottom surface of the dielectric layer has a portion that contacts the porous plug.

[0008] In one embodiment, a plasma chamber is described. The plasma chamber includes an upper electrode. The plasma chamber further includes an electrostatic chuck facing the upper electrode. The chuck includes a dielectric layer having a bottom surface. The chuck also includes a base metal layer having a top surface. The dielectric layer is located above the base metal layer, and the base metal layer has a porous plug. The bottom surface of the dielectric layer has a portion that contacts the porous plug. The chuck is coupled to an RF transmission line and can receive a modified RF signal having a frequency in the range of 10 kHz to 330 kHz.

[0009] In one embodiment, a method is described. The method includes generating an RF signal. The RF signal is generated by an RF generator having an operating frequency range of 10 kHz to 330 kHz. The method further includes correcting the impedance of the RF signal and outputting the corrected RF signal. The method includes receiving the corrected RF signal by a lower electrode. The corrected RF signal is received through a base metal layer of the chuck and a portion of the dielectric layer of the chuck. The dielectric layer is located on top of the base metal layer and has a bottom surface. The base metal layer has a porous plug. The bottom surface of the dielectric layer has a portion that contacts the porous plug.

[0010] Some advantages of the low-frequency RF generator described herein include the ability to generate higher voltages compared to those produced by high-frequency RF generators. When the amount of power supplied to both the low-frequency and high-frequency RF generators is the same, the low-frequency RF generator outputs a higher voltage. Furthermore, the low-frequency RF generator generates the RF signal supplied to the plasma chamber to generate plasma. Plasma ions have greater vertical directionality compared to plasma ions generated using a high-frequency RF generator. Vertically directed plasma ions facilitate increased processing speeds, such as substrate etching rates.

[0011] An additional advantage of the chuck described herein is that the dielectric layer of the chuck eliminates porous plugs. Porous plugs degrade over time and can increase the likelihood of plasma arc discharge and coolant gas ignition. By removing porous plugs from the dielectric layer, the likelihood of arc discharge and coolant gas ignition is reduced.

[0012] Further advantages of the systems and methods described herein include an increase in the amount of power supplied to the plasma chamber. When a low-frequency RF generator is used instead of a high-frequency RF generator, a different number of bins are used, and during the operating cycle of the low-frequency RF generator... Separate High-frequency RF generator frequencyControls the power supply. By using a different number of bins, the amount of power supplied increases.

[0013] Other embodiments will become apparent from the following detailed description in conjunction with the attached drawings. [Brief explanation of the drawing]

[0014] The embodiments can be best understood by referring to the following description in conjunction with the attached drawings.

[0015] [Figure 1A] Figure 1A is a diagram illustrating one embodiment of a system that exemplifies a low-frequency radio frequency (RF) generator.

[0016] [Figure 1B] Figure 1B is a diagram illustrating one embodiment of a system in which a low-frequency radio frequency (RF) generator is used in conjunction with a megahertz (MHz) RF generator.

[0017] [Figure 2A] Figure 2A is a diagram illustrating one embodiment of a system that uses a chuck in conjunction with the RF generator shown in Figure 1A.

[0018] [Figure 2B] Figure 2B is a diagram illustrating one embodiment of a system that demonstrates the use of a porous plug within the dielectric layer of a chuck.

[0019] [Figure 3] Figure 3 is a top view of one embodiment of the porous plug used in the chuck shown in Figure 2A.

[0020] [Figure 4A] Figure 4A is a diagram illustrating one embodiment of a system that demonstrates the operation of a low-frequency RF generator and another low-frequency RF generator.

[0021] [Figure 4B]Figure 4B is a flowchart illustrating an embodiment of a method executed by the system of Figure 4A.

[0022] [Figure 5] Figure 5 is a diagram of an embodiment of a system illustrating a method for adjusting the frequency of an RF signal generated by a higher frequency RF generator during a cycle of an RF signal generated by a high frequency RF generator.

[0023] [Figure 6] Figure 6 is a diagram showing an embodiment of a graph illustrating a voltage signal.

[0024] [Figure 7] Figure 7 is a diagram of an embodiment of a system illustrating binning for the RF generator of Figure 1A.

[0025] [Figure 8] Figure 8 is a diagram showing an embodiment of a graph illustrating a voltage signal generated by a sensor of the system of Figure 7.

[0026] [Figure 9] Figure 9 is a diagram of an embodiment of a substrate illustrating that the vertical directivity of ions of a plasma generated by using a high frequency RF generator is smaller compared to the vertical directivity of ions of a plasma generated by using a low frequency RF generator.

[0027] [Figure 10] Figure 10 is a diagram of an embodiment of a substrate illustrating that the vertical directivity of ions of a plasma generated by using a low frequency RF generator is larger compared to the vertical directivity of ions of a plasma generated by using a high frequency RF generator.

[0028] [Figure 11]Figure 11 is a graph illustrating one embodiment of a case where, when the same amount of power is applied to both a low-frequency RF generator and a high-frequency RF generator, the voltage generated by the low-frequency RF generator is higher than the voltage generated by the high-frequency RF generator.

[0029] [Figure 12A] Figure 12A shows one embodiment of a graph illustrating the ion energy distribution across the entire surface of a substrate.

[0030] [Figure 12B] Figure 12B shows one embodiment of a graph illustrating a different ion energy distribution across the entire surface of a substrate.

[0031] [Figure 12C] Figure 12C shows one embodiment of a graph illustrating yet another ion energy distribution across the entire surface of the substrate. [Modes for carrying out the invention]

[0032] The following embodiments describe systems and methods for using a low-frequency radio frequency (RF) generator and associated electrostatic chucks. It will be apparent that these embodiments can be practiced without some or all of these specific details. In other examples, well-known operations are not described in detail so as not to unnecessarily obscure these embodiments.

[0033] Figure 1A is a diagram of one embodiment of system 100 illustrating a low-frequency RF generator 102. System 100 consists of an RF generator 102, an impedance matching circuit (IMC) 104, and a capacitive coupling circuit. Combined Razma (CCP)This includes a plasma chamber 106, which is an example of a chamber. For example, the RF generator 102 is a low-frequency RF generator having an operating frequency in the range of 10 kHz to 330 kHz. For example, the RF generator 102 has an operating frequency of 100 kHz. For further example, the RF generator 102 operates at a frequency in the range of 90 kHz to 110 kHz. As yet another example, the RF generator 102 is tuned to operate at a frequency in the range of 90 kHz to 110 kHz. As yet another example, the RF generator 102 has an operating frequency of 110 kHz.

[0034] Examples of impedance matching circuits include networks of circuit components such as inductors, resistors, and capacitors, as used herein. For example, an impedance matching circuit comprises one or more series circuits and one or more parallel circuits. Each series circuit includes one or more inductors and one or more capacitors coupled in series with each other. Similarly, each parallel circuit includes one or more inductors and one or more capacitors coupled in series with each other, with one of the inductors and capacitors coupled to ground potential. Each of the one or more parallel circuits is coupled to a corresponding one of the one or more series circuits. The terms impedance matching circuit, matching circuit, and impedance matching network are used interchangeably herein.

[0035] The plasma chamber 106 includes a substrate support 108, such as a chuck, and an upper electrode 110. For example, the upper electrode 110 is made of aluminum or an aluminum-silicon alloy. The upper electrode 110 is sometimes referred to as the upper electrode in this specification. An example of the plasma chamber 106 is a capacitively coupled plasma (CCP) chamber. The chuck may be an electrostatic chuck. When an electrostatic chuck is subjected to a direct current (DC) voltage, it generates an attractive force between the electrostatic electrode of the electrostatic chuck and the substrate S. The substrate S, such as a semiconductor wafer, is placed on the upper surface of the substrate support 108. The substrate support 108 is located below the upper electrode 110, forming a gap between the substrate support 108 and the upper electrode 110.

[0036] The output 114 of the RF generator 102 is connected to the RF cable 11 6 The input 118 of the impedance matching circuit 104 is coupled via the RF transmission line 112, and the output 120 of the impedance matching circuit 104 is coupled to the lower electrode of the substrate support 108 via the RF transmission line 112. For example, the output of a system component is the output port of the component as described herein, and the input of a component is the input port of the component. For example, the output 114 is the output port of the RF generator 102, and the input 118 is the input port of the impedance matching circuit 104. The upper electrode 110 is coupled to a ground potential such as zero potential or reference potential.

[0037] An example of an RF transmission line is a combination of an RF rod, an RF cylinder, and an electrostatic chuck. An insulating material is placed between the RF rod and the wall of the RF tunnel. The RF tunnel surrounds the insulating material, and the insulating material surrounds the RF rod. The RF cylinder is coupled to the RF rod via an RF strap. An RF plasma sheath surrounds the electrostatic chuck when plasma is generated in the plasma chamber 106. In one embodiment, the electrostatic chuck is not part of the RF transmission line.

[0038] The RF generator 102 generates an RF signal 122 and supplies it at output 114. The RF signal 122 is transferred to input 118 via RF cable 116. The impedance matching circuit 104 matches the impedance of the load coupled to output 120 with the impedance of the source coupled to input 118, correcting the impedance of the RF signal 122 and outputting a corrected RF signal 124. Examples of loads coupled to output 120 include the RF transmission line 112 and the plasma chamber 106. Examples of sources coupled to input 118 include the RF cable 116 and the RF generator 102. The corrected RF signal 124 is transferred from output 120 to the lower electrode of the substrate support 108 via RF transmission line 112. Note that the frequencies of the RF signal 122 and the corrected RF signal 124 are the same as the operating frequency of the RF generator 102.

[0039] Plasma is generated or maintained within the plasma chamber 106 when one or more process gases, such as an oxygen-containing gas, a fluorine-containing gas, a hydrogen-containing gas, or a combination thereof, are supplied to a gap in the plasma chamber 106, and a modified RF signal 124 is supplied to the lower electrode of the substrate support 108. The plasma is used to process the substrate S. For example, one or more materials are deposited on the upper surface of the substrate S. As another example, the substrate S is etched. As yet another example, the substrate S is cleaned.

[0040] Figure 1B is a diagram of one embodiment of system 150 illustrating the use of RF generators 102 and 152. System 150 includes RF generator 152 and IMC 154.

[0041] The RF generator 152 has an operating frequency of 60 MHz. For example, the RF generator 152 can be adjusted to operate between 54 MHz and 63 MHz. The RF generator 152 has an output 156 which is coupled to the input 160 of the IMC 154 via an RF cable 158. The IMC 154 has an output 162 which is coupled to the upper electrode 110 via an RF transmission line 164.

[0042] RF Generator 15 2 The system generates an RF signal 166, which is supplied to the input 160 of the IMC 154 via output 156 and RF cable 158. The IMC 154 matches the impedance of the load coupled to output 162 with the impedance of the source coupled to input 160. An example of a load coupled to output 162 is a combination of RF transmission line 164 and plasma chamber 106. An example of a source coupled to input 160 is a combination of RF generator 152 and RF cable 158. Impedance matching is performed to correct the impedance of the RF signal 166 and to supply the corrected RF signal 168 at output 162. The corrected RF signal 168 is supplied to the upper electrode 110 via output 162 and RF transmission line 164. In addition to the corrected RF signals 168 and 124, if one or more process gases are supplied to the plasma chamber 106, plasma is generated or maintained within the plasma chamber 106. The plasma processes the substrate S placed within the plasma chamber 106.

[0043] Figure 2A is a diagram illustrating one embodiment of system 200, which includes a chuck 202 used with the low-frequency RF generator 102 of Figure 1A. System 200 includes the RF generator 102, an impedance matching circuit 104, and a chuck 202 which is an example of a substrate support 108 (Figure 1A). System 200 further includes a high-voltage (HV) DC power (PWR) supply unit 225.

[0044] Figure 2B is a diagram of one embodiment of system 268 illustrating the use of a porous plug 266 within the dielectric layer 256 of a chuck 250. As an example, the porous plug, as used herein, is made from a dielectric material or an insulator. System 268 includes a high-frequency RF generator 254, a matching unit 252, and a chuck 250. The high-frequency RF generator 254 is coupled to the matching unit 252, which is coupled to the base plate 262 of the chuck 250 via an RF transmission line 270. The high-frequency RF generator 254 has an operating frequency higher than that of the low-frequency RF generator 102 (Figure 2A). For example, the high-frequency RF generator 254 has an operating frequency of 400 kHz or 2 megahertz (MHz) or 27 MHz or 60 MHz. System 268 further includes an HV DC power supply unit. As an example, the operating frequency of the 400 kHz RF generator is in the range of 330 kHz to 440 kHz. For example, the operating frequency of a 400kHz RF generator is 330kHz.

[0045] The chuck 250 has a base plate 262 into which several porous plugs PL1 to PL8 are embedded. The porous plugs PL1 to PL8 are shown in the top view 250 of the chuck 250. One of the porous plugs PL3 is shown as porous plug 215.

[0046] Referring back to Figure 2A, the chuck 202 includes a base plate 204 and a dielectric layer 206. The base plate 204 is made from a conductive metal such as aluminum or an aluminum alloy. The dielectric layer 206 is made from a dielectric or insulating material such as ceramic. The base plate 204 may also be referred to herein as the base metal layer or the lower electrode.

[0047] The dielectric layer 206 is located on the upper part of the base plate 204, in contact with the base plate 204. For example, the top surface 208 of the base plate 204 is attached to the bottom surface 210 of the dielectric layer 206. The dielectric layer 206 excludes porous plugs, as will be further described below. For example, porous plugs such as porous plug 266 (Figure 2B) are not embedded within the dielectric layer 206. The porous plug 266 is embedded within a thicker dielectric layer 256 (Figure 2B), such as a ceramic layer. The porous plug 266 increases the thickness T2 of the dielectric layer 256 compared to the thickness T1 of the dielectric layer 206. For example, the dielectric layer 206 has a thickness T1 in the range of 0.7 mm to 0.9 mm. Thickness T1 is the height of the dielectric layer 206 from the bottom surface 210 to the top surface 212 on which the substrate S is placed. The thickness T1 is smaller than the thickness T2 (Figure 2B) of the dielectric layer 256 of the chuck 250 (Figure 2B), which is coupled to the high-frequency RF generator 254 (Figure 2B) via the matching circuit 252 (Figure 2B). For example, the thickness T2 is greater than 0.9 mm. For example, the thickness T2 is in the range of 1 mm to 1.25 mm.

[0048] In addition, a thinner thickness T1 reduces the voltage drop, increasing the amount of power supplied to the chuck 202. For example, the low-frequency RF generator 102 generates a higher voltage compared to the voltage generated by the high-frequency RF generator 254. Furthermore, in this example, when the chuck 250 is coupled to the low-frequency RF generator 102 via the IMC 104 (Figure 1A), the voltage drop increases across the entire height of the dielectric layer 256. Conversely, in this example, when the chuck 202 is coupled to the low-frequency RF generator 102 via the IMC 104, the voltage drop decreases due to the lower height of the dielectric layer 206. Also, in this example, this lower height is lower than the height of the dielectric layer 206. Furthermore, in this example, because of the lower height, the dielectric layer 206 is thinner compared to the dielectric layer 256. Due to the lower voltage drop, the amount of power supplied to the substrate S via the chuck 202 increases.

[0049] When porous plugs PL1-PL8 are embedded within the dielectric layer 206 from the bottom surface 210, they degrade over time, increasing the possibility of plasma arc discharge and coolant gas ignition, as described later. By using the low-frequency RF generator 102 together with the chuck 202, such porous plugs PL1-PL8 are no longer needed within the dielectric layer 206. Therefore, the possibility of arc discharge within the dielectric layer 206 is reduced to a minimum, such as zero.

[0050] The dielectric layer 206 has a side surface 222 having a thickness T1, which extends from the bottom surface 210 to the top surface 212. In one embodiment, the side surface 222 is annular in shape. For example, the top surface 212 is perpendicular or substantially perpendicular to the side surface 222, and the side surface 222 is perpendicular or substantially perpendicular to the bottom surface 210. For example, the first surface is considered substantially perpendicular to the second surface if the angle between the first surface and the second surface is in the range of 85° to 95°.

[0051] The top surface 212 is oriented in the opposite direction to the direction in which the bottom surface 210 is located, and surfaces 212 and 210 are separated from each other by the side surface 222. Each surface 212 and 210 has a linear shape and extends in the horizontal plane, while the side surface 222 has an annular shape.

[0052] The base plate 204 contains several porous plugs PP1, PP2, PP3, PP4, PP5, PP6, and PP7. An example of porous plug PP4 is porous plug 214. As an example, to form each porous plug PP1-PP7, a ceramic slurry is injected into the plug region, which is the space of the channel 218 formed within the base plate 204. The ceramic slurry can be injected from above the top surface 208 of the base plate 226. The ceramic slurry is injected with an initiator, or a catalyst, or an organic monomer, or a combination thereof. The ceramic slurry contains ceramic particles, water, and a dispersant. Furthermore, the ceramic slurry is prepared to generate a foam using a foaming agent. After sufficient foaming, the organic monomer forms a polymer. Next, gas within the foam presses the polymer, forming multiple pores in the resulting porous plug PP1, or PP2, or PP3, or PP4, or PP5, or PP6, or PP7. Subsequently, the foamed ceramic is sintered or "fired" to leave the pore matrix of the porous plug. The pore matrix is ​​uniformly distributed throughout the entire body of the porous plug.

[0053] Continuing the example, the channel has a narrow region 221, followed by a wider region 223, and then another narrow region 231. For example, the narrow region 231 is adjacent to and above the wider region 223. The wider region 223 is above and adjacent to the narrow region 221. Each narrow region 221 and 231 has a diameter smaller than the diameter of the wider region 223. The porous plugs PP1, PP2, PP3, PP4, PP5, PP6, or PP7 have numerous openings, "cells," or pores that allow a coolant gas such as helium to pass through and flow, but limit the mean free path of the coolant gas while it is flowing. The narrow channel 231 is formed within the dielectric layer 206 and extends from the bottom surface 210 to the top surface 212 of the dielectric layer 206. For example, a narrow region (narrow region 231, etc.) of a channel (channel 218, etc.) that transports the coolant gas surrounds the embedded HV electrode 294.

[0054] The porous plugs PP1 to PP7 are shown in the top view 219 of the base plate 226. Each porous plug PP1 to PP7 is embedded in the base plate 204 from the top surface 208 of the base plate 204. For example, a volume on which the porous plug 214 is placed is formed by making a hole in the top surface 208, and the porous plug 214 is embedded in the base plate 204. The porous plugs PP1 to PP7 of the base plate 204 are in contact with the bottom surface 210 of the dielectric layer 206 (for example, in contact with the bottom surface 210, or adjacent to the bottom surface 210, or next to the bottom surface 210). For example, the upper surfaces of the porous plugs PP1 to PP7 of the dielectric layer 206 are in contact with and adjacent to the bottom surface 210. For example, the upper surface 216 of the porous plug 214 is in physical contact with the bottom surface 210 of the dielectric layer 206. To illustrate further, a portion 217 of the bottom surface 210 is in physical contact with the upper surface 216 of the porous plug 214. Similarly, an additional portion of the bottom surface 210 is in physical contact with the upper surfaces of the other porous plugs PP1, PP2, and PP4-PP7 embedded within the base plate 204.

[0055] The porous plugs PP1 to PP7 are located near the periphery or circumference or other edges 227 of the base plate 204, relative to the center 229 of the base plate 204. For example, the porous plugs PP1 to PP7 are arranged radially with respect to the center 229 of the base plate 204. Any two adjacent porous plugs PP1 to PP7 are separated by a portion of the upper surface 208 of the base plate 226. For example, the porous plugs PP1 to PP7 are arranged intermittently along the upper surface 208.

[0056] The chuck 202 includes an embedded HV electrode 294 that clamps the substrate S. The embedded HV electrode 294 is also referred to herein as an electrostatic electrode. The electrostatic electrode is also referred to herein as a clamping electrode. The electrostatic electrode 294 is coupled to a DC HV power supply unit 225. For example, when the DC HV power supply unit 225 supplies power to the electrostatic electrode 294, the electrostatic electrode 294 generates an attractive force that clamps the substrate S to the chuck 202 while the substrate S is being processed.

[0057] As shown in Figure 2A, the base plate 204 has an upper surface 224 and a bottom surface 226. For example, the upper surface 224 has a smaller diameter compared to the diameter of the bottom surface 226. Also, for example, each of the upper surface 224 and the bottom surface 226 is annular in shape. The upper surface 224 is located above the bottom surface 226 and is perpendicular or substantially perpendicular to the top surface 208 of the base plate 204. The intermediate surface 228 of the base plate 204 connects the upper surface 224 to the bottom surface 226. For example, the intermediate surface 228 extends horizontally between the upper surface 224 and the bottom surface 226. The upper surface 208 is greater than the bottom surface 220 of the base plate 204 compared to the height of the intermediate surface 228 from the bottom surface 220. The bottom surface 226 is perpendicular or substantially perpendicular to the bottom surface 220 of the base plate 204.

[0058] The chuck 202 includes multiple channels, such as a channel 218 extending from the bottom surface 220 of the base plate 204 to the top surface 212 of the dielectric layer 206. For example, a channel extends from the bottom surface 220 to the top surface 208 of the base plate 204, and further extends from the bottom surface 210 of the dielectric layer 206 to the top surface 212 of the dielectric layer 206. An example of a channel within the chuck 202 is a through-hole. As an example, there may be 20 to 40 channels within the chuck 202.

[0059] A coolant gas such as helium (He) is supplied to the bottom surface of the substrate S through channels, altering the thermal conductivity between the chuck 202 and the substrate S. For example, the amount of coolant gas supplied through the channels is controlled to either cool the substrate S or reduce the cooling of the substrate S. As another example, when helium is distributed across the entire bottom surface of the substrate S, it uniformly distributes the power of the modified RF signal 124 applied to the bottom surface of the substrate S. The porous plugs in the base plate 204 reduce the amount of opening volume occupied by the coolant gas, reducing the possibility of the coolant gas being ignited by the plasma and reducing the possibility of plasma arc discharge. For example, if porous plugs 214 are not used, each channel and base vinegar A larger gap exists between plate 204 and the upper surface 208, which increases the likelihood of arc discharge and ignition of the coolant gas.

[0060] The dielectric layer 206 includes an electrostatic electrode 294. For example, the electrostatic electrode 294 is embedded within the dielectric layer 222. The electrostatic electrode 294 is located closer to the top surface 212 of the dielectric layer 206 than to the bottom surface 210 of the dielectric layer 206. As an example, the thickness T11 of a portion P1 of the dielectric layer 206 between the electrostatic electrode 294 and the top surface 212 is smaller than the thickness T12 of another portion P2 of the dielectric layer 206 between the electrostatic electrode 294 and the bottom surface 210 of the dielectric layer 206. The sum of thicknesses T11 and T12 is equal to the thickness T1 of the dielectric layer 206. The electrostatic electrode 294 is made from a conductive metal such as aluminum or an aluminum alloy.

[0061] The RF transmission line 112 is coupled to the base plate 204. The modified RF signal 124 is transferred to the base plate 204 via the RF transmission line 112. The modified RF signal 124 reaches the dielectric layer 206 having portion P2. Portion P2 acts as a dielectric between the base plate 204 and the electrostatic electrode 294. Portion P1 of the dielectric layer 206 also acts as a dielectric between the electrostatic electrode 294 and the substrate S.

[0062] The capacitive reactance X1 provided to the RF signal 124 modified by portion P2 is equal to the product of 1 and 2, π, f1, and the ratio of the capacitance C1 of portion P2, where f1 is the operating frequency of the RF generator 102, and the capacitance C1 is the capacitance between the upper surface 208 of the base plate 204 and the electrostatic electrode 294. The capacitance C1 is equal to the product of the dielectric constant εo of portion P2 and the ratio of the overlapping area A1 between the upper surface 208 and the electrostatic electrode 294.

[0063] It should be noted that the capacitive reactance X1 is smaller than another capacitive reactance X2 of a portion of the dielectric layer 256 (Figure 2B) of the chuck 250, which is coupled to the high-frequency RF generator 254 via a matching circuit 252 (Figure 2B). The capacitive reactance X2 is supplied to the modified RF signal 258 output from the matching circuit 252 between the high-frequency RF generator 254 and the dielectric layer 256 of the chuck 250. The capacitive reactance X2 is equal to the ratio of the product of 1 and 2, π, f2, and the capacitance C2 of a portion P3 of the dielectric layer 256, where f2 is the operating frequency of the high-frequency RF generator 254, and the capacitance C2 is the capacitance between the upper surface 260 of the base plate 262 (Figure 2B) of the chuck 250 and the electrostatic electrode 264 (Figure 2B) embedded within the chuck 250. The capacitance C2 is equal to the product of the dielectric constant εo of portion P3 and the ratio of the overlapping area A2 between the upper surface 260 and the electrostatic electrode 264 (Figure 2B).

[0064] It should be noted that the reactance X1 provided to the modified RF signal 124 is smaller than the reactance X2 provided to the modified RF signal 258. For example, if the values ​​of C1 and C2 are the same, reactance X1 will be larger than reactance X2 when frequency f1 is smaller than frequency f2. However, considering that area A1 is equal to or substantially equal to A2, C1 is substantially larger than C2 because the thickness T12 between the top surface 208 of base plate 204 and electrostatic electrode 294 is smaller than the thickness T22 between the top surface 260 of base plate 262 (Figure 2B) and electrostatic electrode 264 (Figure 2B). Areas A1 and A2 are substantially equal if area A2 is only larger or smaller than area A2 by a predetermined percentage, e.g., 10% or less. A larger capacitance C1 compensates for the decrease in frequency f1. Since a larger capacitance compensates for the decrease in frequency f1, porous plugs PL1-PL8 in the dielectric layer 206 are not necessary to uniformly distribute the power of the modified RF signal 124 to the bottom surface of the substrate S. When C1 is substantially larger than C2, the reactance X1 will be smaller than the reactance X2.

[0065] In one embodiment, the base plate 204 includes any other number of porous plugs besides the number shown in Figure 2A. For example, the base plate 204 includes 20 or 30 porous plugs.

[0066] Figure 3 is a top view of one embodiment of the porous plug 214. The porous plug 214 has a diameter larger than the diameter of the channel 218. Furthermore, the porous plug 214 surrounds the channel 218. As an example, both the porous plug 214 and the channel 218 have an annular cross-sectional shape.

[0067] Figure 4A is a diagram illustrating one embodiment of system 400 illustrating the operation of low-frequency RF generator 102 and another low-frequency RF generator 404. Figure 4B is a flowchart illustrating one embodiment of method 450 performed using system 400 of Figure 4A. System 400 includes a host computer 408, RF generator 102, RF generator 404, impedance matching circuit 104, another impedance matching circuit 406, voltage sensor 412, another voltage sensor 414, and plasma chamber 106.

[0068] Examples of host computers 408 include tablets, desktop computers, laptop computers, and smartphones. RF generator 404 has an operating frequency similar to RF generator 102. For example, RF generator 404 has an operating frequency in the range of 10kHz to 330kHz. For example, RF generator 404 has an operating frequency of 100kHz. As another example, RF generator 404 has an operating frequency of 110kHz. As yet another example, RF generator 102 has an operating frequency of 100kHz and RF generator 404 has an operating frequency of 110kHz. As yet another example, RF generator 404 has an operating frequency in the range of 90kHz to 110kHz.

[0069] The plasma chamber 106 includes an edge ring 402 surrounding the upper portion of the substrate support 108. For example, the edge ring 402 is located on the intermediate surface 228 of the base plate 204 (Figure 2A) and surrounds the periphery of the dielectric layer 206 (Figure 2A). The edge ring 402 is sometimes referred to herein as an edge electrode. The edge region of the substrate S is located on the edge ring 402 and is processed by the RF power of a modified RF signal 442 supplied to the edge ring 402. The edge ring 402 is made from a conductive material, such as silicon, or boron-doped single-crystal silicon, or alumina, or silicon carbide, or a silicon carbide layer on top of an alumina layer, or an alloy of silicon, or a combination thereof. The edge ring 402 has an annular shape.

[0070] The host computer 408 includes a processor 416 and a memory device 418. The processor 416 is coupled to the memory device 418. For example, a processor is a controller, or application-specific integrated circuit (ASIC), or programmable logic device (PLD), or central processing unit (CPU), or microcontroller, or microprocessor, and these terms are used interchangeably herein. Examples of memory devices, as used herein, include random access memory (RAM), read-only memory (ROM), and combinations thereof.

[0071] The processor 416 is coupled to the RF generator 102 via a transfer cable 420 and to the RF generator 404 via another transfer cable 422. Examples of transfer cables, as used herein, include cables that transfer data serially, cables that transfer data parallel, or cables that transfer data using the Universal Serial Bus (USB) protocol.

[0072] The RF generator 404 has an output 422 which is coupled to the input 426 of the impedance matching circuit 406 via an RF cable 424. The output 428 of the impedance matching circuit 406 is coupled to the edge ring 402 via an RF transmission line 410.

[0073] Voltage sensor 412 is coupled to output 428, and voltage sensor 414 is coupled to output 120. In addition, voltage sensor 412 is coupled to processor 416 via transfer cable 430, and voltage sensor 414 is coupled to processor 416 via another transfer cable 432.

[0074] The processor 416 transmits control signal 434 to the RF generator 102 via a transfer cable and another control signal 436 to the RF generator 404 via a transfer cable 422. Control signal 434 has recipe information such as one or more parameter levels and one or more frequency levels of the RF signal 122. An example of a parameter is power or voltage, as used herein. Similarly, control signal 436 has recipe information for the RF signal 440 generated by the RF generator 404.

[0075] Each parameter level and frequency level of an RF signal defines the state of the RF signal. For example, if the parameters of an RF signal transition from a first parameter level to a second parameter level during the clock cycle of the synchronization signal 438, the parameters of the RF signal change their state from the first state to the second state. An example of a synchronization signal 438 is a clock signal with multiple clock cycles that repeat periodically. Another example of a synchronization signal 438 is a digital pulse signal with a series of digital pulses that repeat periodically. If the parameters of an RF signal transition from a second parameter level back to a first parameter level during the clock cycle, the parameters of the RF signal change their state from the second state to the first state. As another example, if the frequency of an RF signal transitions from a first frequency level to a second frequency level during the clock cycle of the synchronization signal 438, the frequency of the RF signal changes its state from the first state to the second state. If the frequency of an RF signal transitions from a second frequency level back to a first frequency level during the clock cycle, the frequency of the RF signal changes its state from the second state to the first state.

[0076] As an example, each level of an RF signal parameter contains one or more values ​​of the RF signal parameter. For example, the first level of a parameter contains one or more values, such as one or more peak-to-peak amplitudes or one or more zero-to-peak amplitudes of the RF signal, and the first level excludes the second level of the RF signal parameter. The second level contains one or more values, such as one or more peak-to-peak amplitudes or one or more zero-to-peak amplitudes of the RF signal parameter. To further illustrate, if the first level of a parameter is greater than the second level of a parameter, the minimum value of the first level is greater than the maximum value of the second level. As another example, each level of an RF signal frequency contains one or more values ​​of the RF signal frequency. For example, the first level of the RF signal frequency excludes the second level of the RF signal frequency. To further illustrate, if the first level of frequency is greater than the second level of frequency, the minimum value of the first level is greater than the maximum value of the second level. As yet another example, a variable level, such as a frequency level or parameter level, is an envelope representing the statistics of one or more values ​​of the variable level. For example, a variable level contains the mean or median of multiple values ​​of the variable level.

[0077] When RF generator 102 receives control signal 434, it stores the recipe information for control signal 434 in one or more memory devices of RF generator 102. Similarly, when RF generator 404 receives control signal 436, it stores the recipe information for control signal 436 in one or more memory devices of RF generator 404.

[0078] The processor 416 generates a synchronization signal 438 and transmits it to the RF generator 102 via the transfer cable 420. The processor 416 also transmits the synchronization signal 438 to the RF generator 404 via the transfer cable 422. In response to receiving the synchronization signal 438, the RF generator 102 generates an RF signal 122 according to the recipe information in the control signal 434. For example, the parameters of the RF signal 122 include a first power level for the first state, a second power level for the second state, a first frequency level for the first state, and a second frequency level for the second state.

[0079] Similarly, in response to the reception of the synchronization signal 438, the RF generator 404 generates an RF signal 440 according to the recipe information in the control signal 436. For example, the parameters of the RF signal 440 include a first power level for the first state, a second power level for the second state, a first frequency level for the first state, and a second frequency level for the second state.

[0080] RF signal 440 is transferred to input 426 via RF cable 424. Impedance matching circuit 4 06 The device matches the impedance of the load coupled to output 428 with the impedance of the source coupled to input 426, correcting the impedance of the RF signal 440 and outputting the corrected RF signal 442. Examples of loads coupled to output 428 include the RF transmission line 410 and the plasma chamber 106. Examples of sources coupled to input 426 include the RF cable 424 and the RF generator 404. The corrected RF signal 442 is transferred from output 428 through the RF transmission line 410 to the edge electrode 402. Note that the frequencies of RF signal 440 and the corrected RF signal 442 are the same as the operating frequency of the RF generator 404.

[0081] Plasma is generated or maintained within the plasma chamber 106 when one or more process gases are supplied to the gap in the plasma chamber 106, a modified RF signal 124 is supplied to the lower electrode of the substrate support 108, and a modified RF signal 442 is supplied to the edge electrode 402. The central region of the substrate S is processed by the central portion of the plasma, and the edge regions of the substrate S are processed by the edge portion of the plasma. The edge portion of the plasma surrounds the central portion of the plasma. The central region of the substrate S is located between the base plate 204 (Figure 2A) of the substrate support 108 and the upper electrode 110.

[0082] In operation 451 of method 450, when a modified RF signal 124 is supplied, the voltage sensor 414 measures the voltage of the modified RF signal 124 at output 120 during each state, such as the first or second state of the variable of the RF signal 122, to generate a measurement signal 444, which is then transmitted to the processor 416 via the transfer cable 432. For example, the measurement signal 444 is a voltage signal having the voltage value of the modified RF signal 124, which is measured during the state of the parameter of the RF signal 122. An example of a variable of the RF signal is the frequency of the RF signal or a parameter of the RF signal. Also in operation 451 of method 450, when a modified RF signal 442 is supplied, the voltage sensor 412 measures the voltage of the modified RF signal 442 at output 428 during each state of the variable of the RF signal 440, to generate a measurement signal 446, which is then transmitted to the processor 416 via the transfer cable 430. As an example, the measurement signal 446 is a voltage signal having a voltage value measured between the parameter states of the RF signal 440.

[0083] The processor 416 receives the measurement signal 444 during each state of the RF signal 122, such as the first or second state of the variable, and obtains the voltage measured at output 120 from the measurement signal 444. The processor 416 determines the frequency of the modified RF signal 124 from the voltage measured at output 120 during each state of the RF signal 122 variable. For example, the processor 416 applies a Fourier transform to the measurement signal 444 to obtain the frequency of the measurement signal 444 and determines the frequency of the modified RF signal 124 for the first or second state of the RF signal 122 variable. Exemplarily, the frequency of the measurement signal 444 is the same as the frequency of the modified RF signal 124 for each state of the RF signal 122 variable.

[0084] In addition, the processor 416 determines the phase of the modified RF signal 124 from the measurement signal 444 for each state, such as the first or second state of the variable of the RF signal 122. For example, the processor 416 determines that the phase of the modified RF signal 124 is the same as the phase of the measurement signal 444 for the first or second state of the variable of the RF signal 122.

[0085] Furthermore, the processor 416 determines the setpoints for the parameters of the modified RF signal 124 from the measurement signal 444 for each state, such as the first or second state of the parameters of the RF signal 122. For example, the processor 416 identifies the parameter levels of the modified RF signal 124 parameters between the first or second state of the parameters of the RF signal 122 from the measurement signal 444. The parameter levels of the modified RF signal 124 are examples of the setpoints for the parameters of the modified RF signal 124 for each state of the parameters of the RF signal 122.

[0086] Similarly, processor 416 receives a measurement signal 446 during each state of the RF signal 440, such as the first or second state of the variable, and obtains the measured voltage at output 428 from the measurement signal 446. Processor 416 determines the frequency of the modified RF signal 442 from the measured voltage at output 428 during each state of the RF signal 440. For example, processor 416 applies a Fourier transform to the measurement signal 446 to obtain the frequency of the measurement signal 446 and determines the frequency of the modified RF signal 442 for the first or second state of the RF signal 440. The frequency of the modified RF signal 442 is the same as the frequency of the measurement signal 446 for each state of the RF signal 440.

[0087] Furthermore, the processor 416 determines the phase of the modified RF signal 442 for each state of the variable of the RF signal 440, derived from the measurement signal 446. For example, the processor 416 determines that the phase of the modified RF signal 442 is the same as the phase of the measurement signal 446 for the first or second state of the variable of the RF signal 440.

[0088] Furthermore, for each state of the RF signal 440, such as the first or second state of the variable, the processor 416 determines the setpoints for the parameters of the modified RF signal 442 from the measurement signal 446. For example, the processor 416 identifies the parameter levels of the modified RF signal 442 between the first or second state of the variable of the RF signal 440 from the measurement signal 446. The parameter levels of the modified RF signal 442 are an example of the setpoints for the parameters of the modified RF signal 442 between the first or second state of the variable of the RF signal 440.

[0089] In operation 452 of method 450 shown in Figure 4B, the processor 416 determines whether the determined frequency of the modified RF signal 442 for each state, such as the first or second state of the variable of RF signal 440, is within a predetermined range from the determined frequency of the modified RF signal 124 for the state of the variable of RF signal 122. For example, the processor 416 determines whether the frequency of the modified RF signal 442 is within ±2 percent or ±5 percent of the frequency of the modified RF signal 124. As another example, the processor 416 determines whether the frequency of the modified RF signal 442 matches the frequency of the modified RF signal 124. The predetermined ranges associated with the frequencies of the modified RF signals 442 and 124 are stored in the memory device 418.

[0090] If the processor 416 determines that the frequency of the modified RF signal 442 for a state such as the first or second state of the variable of RF signal 440 is not within a predetermined range from the frequency of the modified RF signal 124 for a state of the variable of RF signal 122, the processor 416 modifies the frequency of RF signal 440 for the state of the variable of RF signal 440, or modifies the frequency of RF signal 122 for the state of the variable of RF signal 122, or modifies the frequencies of RF signals 440 and 122. The processor 416 continues to modify the frequency of RF signal 440 for the state of the variable of RF signal 440, or modifies the frequency of RF signal 122 for the state of the variable of RF signal 122, or modifies the frequencies of RF signals 440 and 122 until it determines that the frequency of the modified RF signal 442 for the state of the variable of RF signal 440 is within a predetermined range from the frequency of the modified RF signal 124 for the state of the variable of RF signal 122. For example, the processor 416 modifies one or more values ​​in the frequency level of the recipe information in the control signal 436 transmitted to the RF generator 404, or one or more values ​​in the frequency level of the recipe information in the control signal 434 transmitted to the RF generator 102, or a combination thereof.

[0091] On the other hand, if it is determined that the frequency of the modified RF signal 442 for a state such as a first or second state of the variable of RF signal 440 is within a predetermined range from the frequency of the modified RF signal 124 for a state of the variable of RF signal 122, then in operation 454 of method 450 shown in Figure 4B, the processor 416 determines whether the phase of the modified RF signal 442 for a state of the variable of RF signal 440 is within a preset range from the phase of the modified RF signal 124 for a state of the variable of RF signal 122. For example, the processor 416 determines whether the phase difference between the phase of the modified RF signal 442 for a first state of the variable of RF signal 440 and the phase of the modified RF signal 124 for a first state of the variable of RF signal 122 is within ±3 percent or within ±5 percent. As another example, the processor 416 determines whether the phase of the modified RF signal 442 for a first state of the variable of RF signal 440 is consistent with the phase of the modified RF signal 124 for a first state of the variable of RF signal 122. The preset ranges associated with the phases of the modified RF signals 124 and 442 are stored in the memory device 418.

[0092] In response to a determination that the phase of the modified RF signal 442 for a state such as the first or second state of the variable of RF signal 440 is not within a preset range from the phase of the modified RF signal 124 for a state of the variable of RF signal 122, the processor 416 modifies the phase of RF signal 440 during the state of the variable of RF signal 440, or modifies the phase of RF signal 122 during the state of the variable of RF signal 122, or a combination thereof. For example, the processor 416 generates another synchronization signal, such as a clock signal, during the first state of the variables of RF signals 122 and 440, and transmits the other synchronization signal to the RF generator 404 via the transfer cable 422. The other synchronization signal is transmitted to the RF generator 404 in place of synchronization signal 438, and is transmitted within a preset period from the time synchronization signal 438 was transmitted to the RF generator 104, reducing or eliminating the phase difference between the phase of the modified RF signal 442 and the phase of the modified RF signal 124. For example, the preset period is the same as the phase difference. An example of a predefined period is a predetermined number of time units, such as microseconds or milliseconds, from the time the synchronization signal 438 is transmitted to the RF generator 104.

[0093] In this example, when RF generator 102 generates RF signal 122 that repeats several states of the variables of RF signal 122 in synchronization with synchronization signal 438, and RF generator 404 generates RF signal 440 that repeats several states of the variables of RF signal 440 in synchronization with another synchronization signal, the modified RF signals 124 and 442 have the same phase. Note that RF signal 122 repeats several states of the variables of RF signal 122 in synchronization with synchronization signal 438 when RF signal 122 begins repeating several states of the variables of RF signal 122 at the same time that synchronization signal 438 is received by RF generator 102 from processor 416. Further note that RF signal 440 repeats several states of the variables of RF signal 440 in synchronization with another synchronization signal when RF signal 440 begins repeating several states of the variables of RF signal 440 at the same time that another synchronization signal is received by RF generator 404 from processor 416. As another example, instead of sending another synchronization signal to the RF generator 404, the processor 416 generates yet another synchronization signal during the first state of the variables of RF signals 122 and 440 and sends yet another synchronization signal via the transfer cable 420 to the RF generator 102 to eliminate or reduce the phase difference. The processor 416 continues to correct the phase of RF signal 440 during each state, such as the first or second state of the variable of RF signal 440, until the phase of the corrected RF signal 442 matches the phase of the corrected RF signal 124 during the state of the variable of RF signal 122.

[0094] On the other hand, in response to the determination that the phase of the modified RF signal 442 for each state, such as the first or second state of the variable of RF signal 440, is within a preset range from the phase of the modified RF signal 124 for the state of the variable of RF signal 122, in operation 454 of method 450 shown in Figure 4B, the processor 416 determines from the parameter setpoint of the measurement signal 446 whether the RF generator 404 is operating at a preset setpoint. For example, the processor 416 determines whether the parameter setpoint acquired in the measurement signal 446 is within a preset range from the parameter level in the recipe information of the control signal 436 transmitted to the RF generator 404. Exemplarily, the preset range is ±5 percent or ±3 percent. As another example, the preset range is achieved when the parameter setpoint acquired from the measurement signal 446 matches the parameter level in the recipe information of the control signal 436.

[0095] If the RF generator 422 determines that it is not operating at a preset setpoint, the processor 416 modifies the parameter level, for example, by increasing or decreasing it to provide a modified setpoint, and transmits the modified setpoint in the recipe information of the control signal 436 to the RF generator 404 to achieve the preset setpoint. The processor 416 repeats operations 451 to 456 for other states, such as the second state of the variable of RF signal 122 and the second state of the variable of RF signal 440. Note that by performing operations 452 to 456, the substrate S is processed uniformly in the edge and central regions of the substrate S.

[0096] In one embodiment, operations 452 to 456 are performed in the order shown in Figure 4B. For example, operation 454 is performed after operation 452, and operation 456 is performed after operation 454.

[0097] In one embodiment, where the RF signals 122 and 440 generated by RF generators 102 and 404 are continuous wave (CW) RF signals, operations 451-456 are repeated for each cycle of the synchronization signal 438. For example, operations 451-456 are performed during the first cycle of the synchronization signal 438. Operations 451-456 are performed during the first cycle based on the measurement signals 444 and 446 generated during the first cycle of the synchronization signal 438. In another example, operations 451-456 are performed during the second cycle of the synchronization signal 438. Operations 451-456 are performed during the second cycle based on the measurement signals 444 and 446 generated during the second cycle of the synchronization signal 438. The second cycle of the synchronization signal 438 is continuous with the first cycle of the synchronization signal 438.

[0098] A CW RF signal does not have multiple states. For example, a CW RF signal has a single state. For example, a CW RF signal has a single variable level having one or more variable values ​​that are within a predetermined range of each other. As another example, the first frequency level of RF signal 440 is the same as the second frequency level of RF signal 440, and the first power level of RF signal 440 is the same as the second power level of RF signal 440. As yet another example, the first frequency level of RF signal 122 is the same as the second frequency level of RF signal 122, and the first power level of RF signal 122 is the same as the second power level of RF signal 122.

[0099] In one embodiment, where the RF signals 122 and 440 generated by RF generators 102 and 404 are CW RF signals, operation 451 is performed during the first cycle of the synchronization signal 438, and operations 452-456 are performed during the second cycle of the synchronization signal 438. Operations 452-456 are performed during the second cycle of the synchronization signal 438 based on the measurement signals 444 and 446 generated during the first cycle of the synchronization signal 438. Furthermore, operations 452-456 performed during the third cycle of the synchronization signal are based on the measurement signals 444 and 446 generated during the second cycle of the synchronization signal 438.

[0100] In one embodiment, the frequency at which operations 451-456 are repeated for RF generators 102 and 404 is lower than the frequency at which operations 451-456 are repeated for the high-frequency RF generators described herein. The high-frequency RF generators are used instead of the low-frequency RF generators 102 and 404.

[0101] In one embodiment, the impedance matching circuit 406 is not coupled to a high-frequency RF generator (not shown). The high-frequency RF generator (not shown) has an operating frequency similar to that of RF generator 254 (Figure 2B). For example, the high-frequency RF generator (not shown) has an operating frequency higher than that of RF generator 102. For example, the high-frequency RF generator (not shown) has an operating frequency of 400 kHz, or 2 MHz, or 27 MHz, or 60 MHz.

[0102] In one embodiment, the RF signal described herein has any number of states, such as three or four, during the clock cycle of the synchronization signal, and has several states that are repeated during each cycle of the synchronization signal. For example, some states occur during the first cycle of the synchronization signal and are repeated during the second cycle of the synchronization signal. The second cycle of the synchronization signal is continuous with the first cycle of the synchronization signal.

[0103] In one embodiment, a dielectric ring is present between the chuck 108 and the edge ring 402. For example, the dielectric ring surrounds the chuck 108, and the edge ring 402 surrounds the dielectric ring.

[0104] Figure 5 shows an embodiment of system 500 illustrating a method for adjusting the frequency of the RF signal 506 generated by RF generator 502 during the cycle of the RF signal 508 generated by high-frequency RF generator 504. System 500 includes a host computer 408, RF generators 502 and 504, an impedance matching circuit 510, a sensor 512, and a plasma chamber 106.

[0105] An example of RF generator 502 is an RF generator having an operating frequency of 2 MHz, 13.56 MHz, 27 MHz, or 60 MHz. An example of RF generator 504 is an RF generator having an operating frequency of 400 kHz, 2 MHz, or 13.56 MHz.

[0106] The operating frequency of RF generator 502 is higher than the operating frequency of RF generator 504. For example, if RF generator 504 has an operating frequency of 400 kHz, RF generator 502 has an operating frequency of 2 MHz, 27 MHz, or 60 MHz.

[0107] The processor 416 is coupled to the RF generators 502 and 504. Furthermore, each RF generator 502 and 504 is coupled to an impedance matching circuit 510, which is coupled to the lower electrode of the substrate support 108. The output of the impedance matching circuit 510 is coupled to a voltage sensor 512. Furthermore, the output of the RF generator 502 is coupled to a power sensor 514. Sensors 512 and 514 are coupled to the processor 416.

[0108] The RF generator 502 receives recipe information from the processor 416 to generate an RF signal 506. The recipe information for generating the RF signal 506 has variable levels for generating the RF signal 506 and is stored in the RF generator 502. Similarly, the RF generator 504 receives recipe information from the processor 416 to generate an RF signal 508. The recipe information for generating the RF signal 508 has variable levels for generating the RF signal 508 and is stored in the RF generator 504.

[0109] In addition, each RF generator 502 and 504 receives a synchronization signal, such as a clock signal. In response to the reception of the synchronization signal, RF generator 502 generates an RF signal 506 with a variable level for generating RF signal 506. Similarly, in response to the reception of the synchronization signal, RF generator 504 generates an RF signal 508 with a variable level for generating RF signal 508.

[0110] The impedance matching circuit 510 receives RF signals 506 and 508, modifies the impedances of RF signals 506 and 508 to supply two modified RF signals, and combines the two modified RF signals to output a modified RF signal 515 at the output 518 of the impedance matching circuit 510. The modified RF signal 515 is supplied from the output 518 of the impedance matching circuit 510 to the lower electrode of the substrate support 108.

[0111] When one or more process gases and a modified RF signal 515 are supplied to the lower electrode of the substrate support 108, plasma is generated or maintained within the plasma chamber 106. Also, when the modified RF signal 515 is supplied to the lower electrode of the substrate support 108, the sensor 512 measures the voltage at the output 518 of the impedance matching circuit 510 and generates a measurement signal 516, such as a voltage signal. The measurement signal 516 is transmitted from the sensor 512 to the processor 416. The power sensor 514 also measures the power at the output 520 of the RF generator 502 and generates a measurement signal 522, which is transmitted to the processor 416.

[0112] The processor 416 receives the measurement signal 516 and divides each cycle of the measurement signal 516 into a predetermined number of m bins, where m is a positive integer. For example, the processor 416 divides each cycle of the measurement signal 516 into 15 or 20 bins. For example, each cycle of the measurement signal 516 is divided into bin 1, bin 2, etc., and continues up to bin m, where m is a positive integer.

[0113] Furthermore, from the measurement signal 522, the processor 416 obtains the power supply value for each bin 1 to m. For example, the processor 416 determines that the power supply value for bin 1 is DP1. Similarly, the processor 416 determines the power supply value for bin 2 as DP2 and for bin m as DPm.

[0114] The processor 416 adjusts the operating frequency of the RF generator 502 for each bin to increase the power supplied to the bin. For example, the processor 416 adjusts the operating frequency of the RF generator 502 for bin 1 from value HF1 to value AHF1. Furthermore, the processor 416 adjusts the operating frequency of the RF generator 502 for bin 2 from value HF2 to value AHF2, and for bin m from value HFm to value AHFm.

[0115] Figure 6 shows one embodiment of graph 600 illustrating a voltage signal 602. The voltage signal 602 follows an example of the measurement signal 516 (Figure 5). Graph 600 plots the voltage value of the voltage signal 602 against time t. The voltage value is plotted on the y-axis, and time t is plotted on the x-axis. Time t is divided into multiple time intervals or periods. For example, time t is divided into equal time intervals, which include a first time interval from time t0 to time t1, a second time interval from time t1 to time t2, a third time interval from time t2 to time t3, and so on, up to a ninth time interval from time t8 to time t9. Also, equal time intervals include a tenth time interval from time t9 to time t10, an eleventh time interval between time t10 and time t11, and so on, up to a twentieth time interval between time t19 and time t20. Each time interval or period of the voltage signal 602 is equal. For example, the first time interval is equal to the second time interval, and the second time interval is equal to the eleventh time interval.

[0116] The voltage signal 602 has multiple cycles, such as cycle 1 and cycle 2, which are repeated over time t. Each cycle is a predetermined number m no bi niThe signal is divided into 20 bins. For example, cycle 1 of voltage signal 602 is divided into 20 bins, and cycle 2 of voltage signal 602 is divided into 20 bins. For example, bin 1 of voltage signal 602 occurs between time t0 and time t1, bin 2 of voltage signal 602 occurs between time t1 and time t2, and so on. Similarly, bin 10 of voltage signal 602 occurs between time t9 and time t10, bin 11 of voltage signal 602 occurs between time t10 and time t11, and bin 20 of voltage signal 602 occurs between time t19 and time t20. In the same way, cycle 2 of voltage signal 602 is divided into 20 bins, each of which has an equal time interval.

[0117] Figure 7 shows an embodiment of system 700 illustrating binning for a low-frequency RF generator 102. System 700 includes RF generator 102, RF generator 701, impedance matching circuit 702, plasma chamber 106, sensors 512 and 514, and host computer 408. RF generator 701 has an operating frequency higher than the operating frequency of RF generator 102. For example, RF generator 701 has an operating frequency of 400 kHz, or 2 MHz, or 13.56 MHz, or 27 MHz, or 60 MHz.

[0118] The output 114 of the RF generator 102 is coupled to the input 704 of the impedance matching circuit 702 via the RF cable 116. The output 706 of the RF generator 701 is coupled to another input 710 of the impedance matching circuit 702 via the RF cable 708. The output 712 of the impedance matching circuit is coupled to the lower electrode of the substrate support 108 via the RF transmission line 112. Sensor 512 is coupled to the output 712 of the impedance matching circuit 702, and power sensor 514 is coupled to the output 706 of the RF generator 701. Processor 416 is coupled to the RF generator 701 via the transfer cable 422. Processor 416 is also coupled to sensor 512 via the RF cable 714. Processor 416 is also coupled to power sensor 514 via the transfer cable 716.

[0119] The processor 416 transmits a control signal 434 to the RF generator 102 via the transfer cable 420. In addition, the processor 416 transmits a control signal 718 to the RF generator 701 via the transfer cable 422. The control signal 718 includes recipe information, such as variable levels for multiple states of variables in the RF signal 720 generated by the RF generator 701. For example, the control signal 718 includes parameter levels and frequency levels for a first state of the parameters of the RF signal 720, and parameter levels and frequency levels for a second state of the parameters of the RF signal 720. Upon receiving the control signal 718, the RF generator 701 stores the recipe information received in the control signal 718 in one or more memory devices of the RF generator 701.

[0120] The processor 416 simultaneously transmits a synchronization signal 438 to the RF generators 102 and 701. In response to the reception of the synchronization signal 438, the RF signal 122 is generated by the RF generator 102 in the same manner as described above with reference to Figure 4A. Also in response to the reception of the synchronization signal 438, the RF generator 701 generates an RF signal 720 having the variable level received within the recipe information of the control signal 718.

[0121] RF signal 122 is transferred to input 704 via RF cable 116, and RF signal 720 is transferred to input 710 of impedance matching circuit 702 via RF cable 708. Input 704 is coupled to output 712 via first branch circuit of impedance matching circuit 702, and input 710 is coupled to output 712 via second branch circuit of impedance matching circuit 702.

[0122] When the RF signal 122 is transferred from input 704 via the first branching circuit, the impedance matching circuit 702 matches the impedance of the load coupled to the output 712 of the impedance matching circuit 702 with the impedance of the source coupled to input 704 of the impedance matching circuit 702, thereby correcting the impedance of the RF signal 120 and supplying the first corrected RF signal. Examples of loads coupled to output 712 include the RF transmission line 112 and the plasma chamber 106. Examples of sources coupled to input 704 include the RF cable 116 and the RF generator 102.

[0123] Furthermore, when the RF signal 720 is transferred from the input 710 via the second branching circuit, the impedance matching circuit 702 matches the impedance of the load coupled to the output 712 with the impedance of the source coupled to the input 710 of the impedance matching circuit 702, thereby correcting the impedance of the RF signal 720 and supplying a second corrected RF signal. Examples of sources coupled to the input 710 include the RF cable 702 and the RF generator 701. The first corrected RF signal is coupled with the second corrected RF signal at the output 712, and the output 712 outputs a corrected RF signal 722. The corrected RF signal 722 is transferred to the lower electrode of the plasma chamber 106 via the RF transmission line 112. When one or more process gases and the corrected RF signal 722 are supplied to the plasma chamber 106, plasma is generated or produced within the plasma chamber 106, and the substrate S is processed within the plasma chamber 106.

[0124] When the modified RF signal 722 is supplied, the sensor 512 measures the voltage at output 712 and outputs a measurement signal 724, which is then supplied to the processor 416 via the transfer cable 714. An example of the measurement signal 724 is a voltage signal. The power sensor 514 also measures power, such as the power supplied at output 706, and generates a measurement signal 726, which is then supplied to the processor 416 via the transfer cable 716. The power supplied at output 706 is the difference between the power supplied by the RF generator 701 at output 706 and the power reflected back to the RF generator 701 at output 706. The power supplied by the RF generator 701 is the amount of power in the RF signal 720 supplied by the RF generator 701. RF generator 70 1 The reflected power is then reflected from the plasma chamber 106 through the RF transmission line 112, output 712, the second branch circuit of the impedance matching circuit 702, input 710, and RF cable 708 to input 706 of the RF generator 701.

[0125] When the measurement signal 724 is received, the processor 416 divides each cycle of the measurement signal 724 into multiple bins, for example, bins 1a, 2a, ~na, where n is a positive integer. For example, if RF generator 102 is used in system 700 in place of or replacing a high-frequency RF generator such as RF generator 504 and RF generator 502 (Figure 5), the processor 416 receives an instruction from the user that RF generator 102, which has a lower operating frequency, be coupled into system 700. If a high-frequency generator is used in system 700, the high-frequency RF generator is coupled to input 704 via RF cable 116. The instruction is received via an input device such as a mouse, or keyboard, or stylus, or keypad coupled to the processor 416. The instruction includes the operating frequency of RF generator 102. The processor 416 receives the instruction and determines that the operating frequency of RF generator 102 is lower than the operating frequency of the high-frequency RF generator currently disconnected from input 704.

[0126] After determining that the operating frequency of the RF generator 102 coupled to system 700 is lower than the operating frequency of the high-frequency RF generator previously coupled to the input 704 of the impedance matching circuit 702 of system 700, upon receiving the measurement signal 724, the processor 416 divides each cycle of the measurement signal 724 into a different number of bins than the predetermined number of bins for each cycle of the measurement signal 516 in Figure 5. For example, the processor 416 divides each cycle of the measurement signal 724 into a number of bins greater than the predetermined number of bins that divide each cycle of the measurement signal 516, for example, 50 or 60 bins. This is because, when the low-frequency RF generator 102 is used instead of the high-frequency RF generator 504 (Figure 5) or 502 (Figure 5), the impedance of the plasma in the plasma chamber 106 does not change as quickly. As another example, the processor 416 divides each cycle of the measurement signal 724 into a number of bins less than the number of bins for each cycle of the measurement signal 516, for example, 5 bins. or Divide it into 10 bottles.

[0127] Note that each bin represents a time interval during which the measurement signal, divided into multiple bins, is generated. A time interval is a period that occurs during the cycle of the measurement signal. For example, bin 1a represents the first time interval during which the measurement signal 724 is generated by sensor 512, and bin 2a represents the second time interval during which the measurement signal 724 is generated by sensor 512. The second time interval for bin 2a is consecutive to the first time interval for bin 1a. Both the first and second time intervals occur during each cycle of the measurement signal.

[0128] The processor 416 determines the power supplied for each bin of the measurement signal 726 from the measurement signal 726. For example, the processor 416 determines that the amount of power supplied at output 706 during the first time interval of bin 1a of the measurement signal 726 is DP1a. For example, the processor 416 generates a statistic such as the mean or median of the power values ​​of the measurement signal 726 generated during the first time interval of bin 1a within the cycle of the measurement signal 726. The statistic is the amount DP1a. Similarly, the processor 416 determines that the amount of power supplied at output 706 during the second time interval of bin 2a of the measurement signal 726 is DP2a, and the amount of power supplied at output during the nth time interval of bin na of the measurement signal 726 is DPna. In this example, each cycle of the measurement signal 726 is divided into n bins or n time intervals.

[0129] The processor 416 determines that for bin 1a, the power supplied to bin 1a increases from value DP1a to an increment such as IDP1a by adjusting the frequency of the RF signal 720 from value HF1a to value AHF1a. For example, during a time interval for bin 1a, the processor 416 changes a value such as the frequency level statistics in the recipe information of the control signal 718 transmitted to the RF generator 701 from HF1a to AHF1a. After the control signal 718 with the adjusted frequency value AHF1a for bin 1a is received by the RF generator 701, during the next cycle of the synchronization signal 438, the RF generator 701 generates an RF signal 720 with the adjusted frequency value AHF1a for bin 1a. Also, during the period for bin 1a when the RF signal 720 has the adjusted frequency value AHF1a, the power sensor 514 measures an increment in the supplied power such as IDP1a and transmits the increment to the processor 416 via the transfer cable 716. The processor 416 determines that for bin 1a, adjusting the frequency value from HF1a to AHF1a increases the power supplied by the power sensor 514 from DP1a to IDP1a. Having made this determination, the processor 416 maintains the frequency value of the RF signal 720 for bin 1a at AHF1a instead of HF1a. Note that the frequency of the RF signal is adjusted by increasing or decreasing the frequency of the RF signal. On the other hand, if the processor 416 determines that for bin 1a, adjusting the frequency from HF1a to AHF1a decreases the power supplied by the power sensor 514 from DP1a to DDP1a, the processor 416 maintains the frequency value of the RF signal 720 at HF1a for bin 1a.

[0130] Similarly, for each of the remaining bins 2a to na of the measurement signal 724, the processor 416 determines whether the respective power values ​​DP2a to DPna increase or decrease by adjusting the respective frequency values ​​HF2a to HFna to the respective frequency values ​​AHF2a to AHFna. For example, for bin na, the processor 416 determines whether the power value increases from DPna to an increased power value IDPna, or decreases from DPna to a decreased power value DDPna, by adjusting the frequency value HFna of the RF signal 720 to AHFna. If it is determined that the power DPna increases by adjusting the frequency value of the RF signal 720 from HFna to AHFna for bin na, the processor 416 controls the RF generator 701 to generate an RF signal 720 having an adjusted frequency value AHFna, such as a frequency level statistic for bin na. On the other hand, if it is determined that the transmitted power DPna decreases by adjusting the frequency value of the RF signal 720 for bin na from HFna to AHFna, the processor 416 controls the RF generator 701 to continue generating the RF signal 720 having the frequency value HFna.

[0131] In one embodiment, the time intervals of the bins of the measurement signal 724 coincide with the states of the variables of the RF signal 720. For example, during the time interval for bin 1a, the variables of the RF signal 720 are in a first state; during the time interval for bin 2a, the variables of the RF signal 720 are in a second state, and so on. For example, during the time interval for bin na, the variables of the RF signal 720 are in the nth state. The variables of the RF signal 720 transition from one state to another at the end of the time interval for a bin. For example, the variables of the RF signal 720 transition from the first state to the second state at the end of the time interval for bin 1a, from the second state to the third state at the end of the time interval for bin 2a, and from the (n-1)th state to the nth state at the end of the time interval for bin (n-1)a of the measurement signal 724.

[0132] Figure 8 is an embodiment of graph 800 illustrating the voltage signal 802 generated by the sensor 512 in Figure 7. Graph 800 plots the voltage measured by the sensor 512 against time t at the output 712 of the impedance matching circuit 702 (Figure 7). The voltage measured by the sensor 512 is plotted on the y-axis, and time t is plotted on the x-axis. The voltage signal 802 is output by the sensor 512. The voltage signal 802 has multiple cycles, such as cycle 1, cycle 2, etc. Each cycle of the voltage signal 802 is repeated over time t.

[0133] The processor 416 (Figure 7) receives the voltage signal 802 from the sensor 512 via the transfer cable 714 (Figure 7) and divides each cycle of the voltage signal 802 into a predetermined number of bins. For example, the processor 416 divides cycle 1 of the voltage signal 802 into 60 bins from bin 1a to bin 60a. Bin 1a continues from time t0 to time t1. Similarly, bin 2a continues from time t1 to time t2. Bin 30a continues from time t29 to time t30, and bin 60a continues from time t59 to time t60.

[0134] Each time segment on the x-axis of graph 800 is equal. For example, the time segment between times t0 and t1 is equal to the time segment between times t1 and t2. Therefore, bin 1a continues over a time interval equal to the time interval over which bin 2a follows.

[0135] It should be noted that the predetermined number of bins generated by the processor 416 for the low-frequency RF generator 102 (Figure 7) is different from the preset number of bins generated by the processor 416 for high-frequency RF generators such as RF generator 504 (Figure 5) or RF generator 502 (Figure 5). For example, if RF generator 504 or RF generator 502 is coupled to input 704 of impedance matching circuit 702 (Figure 7) via RF cable 116 instead of RF generator 102, the processor 416 divides each cycle of the voltage signal received from sensor 512 into a preset number of bins. When RF generator 102 is coupled to input 704, a predetermined number of bins are used.

[0136] In one embodiment, the processor 416 divides each cycle of the voltage signal 802 into a different number of bins than those shown in Figure 8. For example, the processor 416 divides the voltage signal 802 into more than 60 bins or fewer than 60 bins.

[0137] Figure 9 shows an embodiment of a substrate 900 illustrating that the vertical orientation of ions in a plasma generated using a high-frequency RF generator is smaller than that of ions in a plasma generated using a low-frequency RF generator. The substrate 900 includes a substrate layer 902, one or more substrate stack layers 904, and a mask layer 906. An example of the substrate layer 902 is a silicon layer. An example of one or more substrate stack layers 904 is a layer of aluminum nitride (AlN) superimposed on the substrate layer 902, a buffer layer superimposed on the AlN layer, and gallium nitride (GaN) superimposed on the buffer layer. The buffer layer may be a dielectric layer. Another example of one or more substrate stack layers 904 is a pad superimposed on the substrate layer 902, a barrier and seed layer superimposed on the pad, and a photoresist layer superimposed on the barrier and seed layer. The photoresist layer is patterned by applying the mask layer 906 to form features and superimpose copper layers within the features. One of the features is shown as feature 908.

[0138] If RF generator 504 or RF generator 502 is coupled to the input 704 of the impedance matching circuit 702 (Figure 7) via RF cable 116 instead of RF generator 102, the vertical orientation 910 of plasma ions formed in the plasma chamber 106 becomes smaller. Consequently, the etching rate that etches the features decreases. Also, plasma ions with vertical orientation 910 etch the sidewalls of one or more substrate layers 904.

[0139] Figure 10 shows an embodiment of substrate 1000 illustrating that the vertical orientation 910 of plasma ions generated by using a low-frequency RF generator is greater than the vertical orientation 1004 of plasma ions generated by using a high-frequency RF generator. Substrate 1000 has layers 902, 904, and 906 of the same type as substrate 900 (Figure 9), except that one or more layers 904 in substrate 1000 are not etched or are only minimally etched by plasma ions. For example, a feature such as feature 1002 is formed on one or more substrate stack layers 904. The feature is etched at a faster rate than the feature is etched in substrate 900. This is due to the vertical orientation 1004 of plasma ions.

[0140] When the low-frequency RF generator 102 is coupled to the input 704 of the impedance matching circuit 702 (Figure 7) via the RF cable 116 instead of the high-frequency RF generator 504 or 502, the vertical orientation 910 of the plasma ions formed in the plasma chamber 106 increases to a vertical orientation 1004. Therefore, the etching rate that etches the features increases. Also, plasma ions with a vertical orientation 1004 do not etch the sidewalls of one or more substrate layers 904.

[0141] The increase in the vertical direction 1004 results in less etching, or no etching at all, of the sidewalls of one or more substrate layers 904 on substrate 1000 compared to the amount of etching of the sidewalls of one or more substrate layers 904 on substrate 900. Furthermore, the etching rate increases when etching features on substrate 1000 compared to etching features on substrate 900.

[0142] Furthermore, the amount of control over the limit dimension (CD) of one or more substrate layers 904 of substrate 1000 increases compared to the amount of control over the limit dimension (CD) of one or more substrate layers 904 of substrate 900. For example, the width of feature 1002 is smaller than the width of feature 908 in order to form a narrower and more uniform feature within one or more substrate layers 904 of substrate 1000. Feature 1002 is narrower than feature 908.

[0143] Because the vertically focused 1004 is greater than the vertically focused 910, the selectivity of one or more substrate layers 904 of substrate 1000 is increased compared to the selectivity of one or more substrate layers 904 of substrate 900. For example, the ratio of the etching rate of one or more substrate layers 904 of substrate 1000 to the etching rate of the mask layer 906 of substrate 1000 is increased compared to the ratio of the etching rate of one or more substrate layers 904 of substrate 900 to the etching rate of the mask layer 906 of substrate 900.

[0144] While Figures 9 and 10 illustrate etching rates, it should be noted that in some embodiments, replacing the low-frequency RF generator 102 with a high-frequency RF generator increases processing speeds such as substrate deposition rate, sputtering rate, or cleaning rate.

[0145] Figure 11 is an embodiment of Graph 1100 illustrating that when the same amount of power is applied to both a low-frequency RF generator and a high-frequency RF generator, the voltage generated by the low-frequency RF generator is higher than the voltage generated by the high-frequency RF generator. Graph 1100 plots voltage signal 1102 and another voltage signal 1104 against power. Voltage signal 1102 has a voltage measured at the output 120 (Figure 1A) of the impedance matching circuit 104 (Figure 1A). Voltage signal 1104 has a voltage measured at the output of the matching circuit 252 (Figure 2B). Voltage signal 1102 is generated when RF generator 102 is coupled to input 118 of impedance matching circuit 104 (Figure 1A) via RF cable 116 (Figure 1A), and voltage signal 1104 is generated when a high-frequency RF generator, such as RF generator 504 (Figure 5), or RF generator 502 (Figure 5), or RF generator 254 (Figure 2B), or RF generator 701 (Figure 7), is coupled to matching circuit 252. Note that 400 kHz shown in Figure 11 is an example of a high-frequency RF generator.

[0146] It should be further noted that when the same amount of power P2 is supplied to both the low-frequency RF generator 102 and the high-frequency RF generator 102, a voltage V2 is generated at the output of the matching unit 252, and voltage V2 is greater than the voltage V1 generated at output 120. For example, voltage V2 is 2 to 3 times voltage V1. For another example, voltage V2 is 2 times voltage V1. For yet another example, voltage V2 is 3 times voltage V1. Voltage V1 is a point on voltage signal 1104, and voltage V2 is a point on voltage signal 1102. It should also be noted that when the same amount of voltage V1 is generated at output 120, the amount of power P1 supplied to the low-frequency RF generator 102 is less than the amount of power P2 supplied to the high-frequency RF generator.

[0147] Therefore, a lower amount of power is supplied to the RF generator 102 compared to the amount of power supplied to the high-frequency RF generator in order to achieve the same process result, such as etching rate, deposition rate, or sputtering rate. By supplying a lower amount of power, the same process result is achieved by the RF generator 102 generating an equal amount of voltage compared to the high-frequency RF generator.

[0148] Figure 12A is an embodiment of graph 1200 illustrating the ion energy and angular distribution across the entire top surface of the substrate S (Figure 1A). Graph 1200 plots the ion energy in electron volts (eV) on the y-axis and the angular theta (θ) extending horizontally across the top surface of the substrate S on the x-axis. The ion energy is that of the plasma generated in the plasma chamber 106 (Figure 1A) when a 400 kHz RF generator is coupled to the substrate support 108 (Figure 1A) via a matching circuit 252 (Figure 2B).

[0149] Figure 12B is an embodiment of Graph 1202 illustrating a different ion energy and angular distribution across the entire top surface of the substrate S (Figure 1A). Graph 1202 plots ion energy on the y-axis and the angle θ extending horizontally across the top surface of the substrate S on the x-axis. The ion energy shown in Graph 1202 is that of the plasma generated in the plasma chamber 106 (Figure 1A) when the RF generator 102 is coupled to the substrate support 108 (Figure 1A) via the IMC 104.

[0150] The ion angle distribution across the entire top surface of the substrate S is narrower in Graph 1202 compared to Graph 1200. For example, the ion angle distribution shown in Graph 1202 is in the range of -10 degrees to 10 degrees on the top surface of the substrate S. In comparison, the ion angle distribution shown in Graph 1200 is in the range of angles greater than -10 degrees to greater than 10 degrees on the top surface of the substrate S. The low-frequency RF generator 102 narrows the ion angle distribution, thereby increasing the processing speed of the substrate S, such as the etching rate or deposition rate. Note that the RF generator 102 operates at a frequency of 100 kHz to generate Graph 1202.

[0151] Figure 12C is an embodiment of graph 1204 illustrating yet another ion energy and angular distribution on the top surface of the substrate S (Figure 1A). Graph 1204 plots ion energy on the y-axis and the angle θ extending horizontally across the top surface of the substrate S on the x-axis. The ion energy shown in graph 1204 is from the plasma generated in the plasma chamber 106 (Figure 1A) when the RF generator 102 is coupled to the substrate support 108 (Figure 1A) via the IMC 104. As shown, the ion angular distribution across the entire top surface of the substrate S is narrower in graph 1204 compared to that shown in graph 1200. For example, most of the ion energy in graph 1204 is concentrated within the range of -4 to 4 degrees on the top surface of the substrate S. Note that the RF generator 102 operates at a frequency of 50 kHz to generate graph 1204.

[0152] The embodiments described herein can be implemented in a variety of computer system configurations, including handheld hardware units, microprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, and mainframe computers. The embodiments can also be implemented in distributed computing environments where tasks are performed by remote processing hardware units linked over a network.

[0153] In some embodiments, the controller is part of a system which may be part of the examples described above. Such a system includes semiconductor processing equipment which includes one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (such as wafer pedestals, gas flow systems, etc.). These systems are integrated with electronics for controlling pre-processing, processing, and post-processing operations of semiconductor wafers or substrates. Such electronics may be referred to as “controllers” and may control various components or sub-components of one or more systems. Depending on the processing requirements and / or the type of system, the controller is programmed to control one of the processes disclosed herein. Such processes include supplying process gases, setting temperature (e.g., heating and / or cooling), setting pressure, setting vacuum, setting power, setting RF generators, setting RF matching circuits, setting frequency, setting flow rates, setting fluid supply, setting position and operation, loading and unloading wafers to and from tools and other transfer tools coupled to or interlocked with the system, and / or loading and unloading wafers to and from load locks.

[0154] In a broad sense, in various embodiments, a controller is defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive and issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as ASICs, PLDs, and / or one or more microprocessors, i.e., microcontrollers that execute program instructions (e.g., software). Program instructions are instructions communicated to the controller in the form of various individual settings (or program files) that define parameters, coefficients, variables, etc., for carrying out a particular process on or for a semiconductor wafer or in a system. In some embodiments, program instructions are part of a recipe defined by a process engineer to realize one or more processing steps in the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or wafer dies.

[0155] In some embodiments, the controller is part of a computer that is integrated with or coupled to the system, or otherwise networked to the system, or is coupled to such a computer, or a combination thereof. For example, the controller resides in the “cloud” and is all or part of the fab host computer system. This enables remote access to wafer processing. The computer enables remote access to the system to monitor the current progress of fabrication operations, review the history of past fabrication operations, examine trends or performance criteria from multiple fabrication operations, modify parameters of the current process, set processing steps following the current process, or start a new process.

[0156] In some embodiments, a remote computer (e.g., a server) provides process recipes to the system via a network. Such a network may include a local network or the Internet. The remote computer includes a user interface that enables the entry or programming of parameters and / or settings, which are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data, which specifies the parameters, coefficients, and / or variables for each processing step performed during one or more operations. It should be understood that the parameters, coefficients, and / or variables are specific to the type of process being performed and the type of tool the controller is configured to interface with or control. Thus, as described above, the controller is distributed by including, for example, one or more separate controllers that are networked together and cooperate toward a common purpose (such as the processes and controls described herein). An example of a distributed controller for such purposes is one or more integrated circuits on a chamber that communicate with one or more integrated circuits that are remotely located (e.g., at the platform level or as part of a remote computer) and combined to control the processes in the chamber.

[0157] In various embodiments, exemplary systems to which the method is applied include, but are not limited to, plasma etching chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, bevel edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, tracking chambers or modules, and any other semiconductor processing systems related to or used in the fabrication and / or manufacture of semiconductor wafers.

[0158] It should be further noted that in some embodiments, the above-described operation applies to several types of plasma chambers, such as plasma chambers containing inductively coupled plasma (ICP) reactors, transformer-coupled plasma chambers, conductive tools, dielectric tools, and plasma chambers containing electron cyclotron resonance (ECR) reactors. For example, one or more RF generators are coupled to inductors within an ICP reactor. Examples of inductor shapes include solenoids, dome coils, and flat coils.

[0159] As described above, depending on one or more process steps performed by the tool, the host computer communicates with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, the main computer, another controller, or tools used for material handling to load and unload wafer containers to and from tool locations and / or load ports within the semiconductor manufacturing plant.

[0160] With the above embodiments in mind, it should be understood that some embodiments utilize various computer implementation operations involving data stored in a computer system. These operations are operations that physically manipulate physical quantities. Any of the operations described herein that form part of the embodiments are useful mechanical operations.

[0161] Some embodiments also relate to hardware units or devices for performing these operations. These devices are specifically built for dedicated computers. When defined as a dedicated computer, the computer is capable of operating for its dedicated purpose, but performs other processes, program executions, or routines that are not part of its dedicated purpose.

[0162] In some embodiments, the operation may be processed by a computer that is selectively activated or configured by one or more computer programs stored in computer memory, a cache, or retrieved via a computer network. If the data is retrieved via a computer network, that data may be processed by other computers on the computer network (e.g., a cloud of computing resources).

[0163] One or more embodiments may also be fabricated as computer-readable code on a non-temporary computer-readable medium. A non-temporary computer-readable medium is any data storage hardware unit that stores data (e.g., a memory device), which is then read by a computer system. Examples of non-temporary computer-readable media include hard drives, network-attached storage (NAS), ROM, RAM, compact disk ROM (CD-ROM), CD recordable (CD-R), CD rewritable (CD-RW), magnetic tape, and other optical and non-optical data storage hardware units. In some embodiments, the non-temporary computer-readable medium includes computer-readable tangible media distributed on a network-connected computer system so that the computer-readable code is stored and executed in a distributed manner.

[0164] Although the above method operations were described in a specific order, it should be understood that in various embodiments, other housekeeping operations may be performed between each operation, or each method operation may be timed to occur at slightly different times, or they may be distributed in a system that allows each method operation to occur at various intervals, or they may be performed in an order different from the order described above.

[0165] It should be further noted that in one embodiment, without departing from the scope described in the various embodiments described herein, one or more features of any embodiment described above may be combined with one or more features of any other embodiment described above.

[0166] Although the embodiments described above have been explained in some detail for clearer understanding, it will be apparent that certain changes and modifications can be practiced within the scope of the appended claims. Therefore, these embodiments should be considered illustrative rather than restrictive, and embodiments should not be limited to the details described herein. This disclosure includes the following examples of applications. [Application Example 1] A first radio frequency (RF) generator having an operating frequency range of 10 kilohertz (kHz) to 330 kHz, wherein the first RF generator is configured to generate a first RF signal, A first impedance matching circuit coupled to the first RF generator to receive the first RF signal and modifying the impedance of the first RF signal to output a first modified RF signal, A plasma chamber configured to receive the first modified RF signal, wherein the plasma chamber includes a chuck having a dielectric layer and a base metal layer, the dielectric layer being located above the base metal layer, the dielectric layer having a bottom surface, the base metal layer having a porous plug, and the bottom surface of the dielectric layer having a portion in contact with the porous plug. A system that includes these features. [Application Example 2] The system according to claim 1, The plasma chamber includes an edge ring surrounding the chuck, and the system is A second RF generator having an operating frequency range of 10kHz to 330kHz, wherein the second RF generator is configured to generate a second RF signal, A second impedance matching circuit coupled to the second RF generator to receive the second RF signal and modifying the impedance of the second RF signal to output a second modified RF signal. Furthermore, The edge ring is coupled to the second impedance circuit and receives the second modified RF signal. system. [Application Example 3] The system according to claim 2, A host computer coupled to the first and second RF generators, wherein the host computer is The second RF generator is controlled until the frequency of the second modified RF signal falls within a predetermined range from the frequency of the first modified RF signal. The second RF generator is controlled until the phase of the second modified RF signal falls within a preset range from the phase of the first modified RF signal. The second RF generator is controlled to achieve the voltage setpoint. A host computer configured in this way A system that further enhances this feature. [Application Example 4] The system according to claim 3, The predetermined range is achieved when the operating frequencies of the first and second modified RF signals are the same, in a system. [Application Example 5] The system according to claim 3, The preset range is achieved when the phases of the first and second modified RF signals are the same, in a system. [Application Example 6] The system according to claim 1, A second RF generator configured to generate a second RF signal, A host computer coupled to the first and second RF generators, wherein the host computer is Upon receiving an instruction that the first RF generator has been replaced by a third RF generator, the third RF generator has a higher operating frequency than the first RF generator. A voltage signal having the frequency of the first RF signal is received, The voltage signal is divided into a first number of bins distinct from a second number of bins, the second number of bins being generated when the third RF generator is used. A host computer configured in such a way A system that further enhances this feature. [Application Example 7] The system according to claim 1, The dielectric layer excludes the porous plug, and the first RF generator has an operating frequency range of 90 kHz to 110 kHz. [Application Example 8] Upper electrode and A chuck facing the upper electrode, wherein the chuck is A dielectric layer having a bottom surface, and A base metal layer, wherein the dielectric layer is located on top of the base metal layer, the base metal layer has a porous plug, and the bottom surface of the dielectric layer has a portion that contacts the porous plug. Chucks and Equipped with, The chuck is coupled to a first RF transmission line and is configured to receive a first modified RF signal having a frequency in the range of 10 kilohertz (kHz) to 330 kHz. Plasma chamber. [Application Example 9] A plasma chamber according to claim 8, The first RF transmission line is coupled to a first RF generator via a first impedance matching circuit, and the first RF generator is a plasma chamber having an operating frequency in the range of 10 kHz to 330 kHz. [Application Example 10] A plasma chamber according to claim 9, Edge electrodes surrounding the chuck Furthermore, The edge electrode is coupled to a second RF transmission line and configured to receive a second modified RF signal having a frequency in the range of 10 kHz to 330 kHz. Plasma chamber. [Application Example 11] A plasma chamber according to claim 10, The second RF transmission line is coupled to a second RF generator via a second impedance matching circuit, and the second RF generator is a plasma chamber having an operating frequency in the range of 10 kHz to 330 kHz. [Application Example 12] A plasma chamber according to claim 11, A plasma chamber in which the phase of the first modified RF signal is within a preset range from the phase of the second modified RF signal. [Application Example 13] A plasma chamber according to claim 11, A plasma chamber in which the frequency of the first modified RF signal is within a predetermined range from the frequency of the second modified RF signal. [Application Example 14] A plasma chamber according to claim 8, The dielectric layer excludes porous plugs, the first RF transmission line is coupled to a first RF generator via a first impedance matching circuit, and the first RF generator is a plasma chamber having an operating frequency range of 90 kHz to 110 kHz. [Application Example 15] The invention relates to generating a first radio frequency (RF) signal, wherein the first RF signal is generated by a first RF generator having an operating frequency range of 10 kilohertz (kHz) to 330 kHz. The impedance of the first RF signal is corrected, and the corrected RF signal is output. The lower electrode of the chuck receives the first modified RF signal via the base metal layer and a portion of the dielectric layer of the chuck. Includes, The dielectric layer is located on top of the base metal layer, The dielectric layer has a bottom surface, The base metal layer has a porous plug, and the bottom surface of the dielectric layer has a portion that contacts the porous plug. method. [Application Example 16] The method according to claim 15, The dielectric layer excludes the porous plug, and the first RF generator has an operating frequency range of 90 kHz to 110 kHz. [Application Example 17] The method according to claim 15, The second RF generator generates a second RF signal, wherein the second RF generator has an operating frequency range of 10 kHz to 330 kHz. The system receives the second RF signal, corrects the impedance of the second RF signal, and outputs a second corrected RF signal. The edge ring receives the second modified RF signal, the edge ring surrounds the chuck and Methods that further include this. [Application Example 18] The method according to claim 17, Controlling the second modified RF signal to have a frequency within a predetermined range from the frequency of the first modified RF signal, Controlling the second modified RF signal to achieve that its phase falls within a preset range from the phase of the first modified RF signal, Controlling the second RF generator to achieve a voltage setpoint Methods that further include this. [Application Example 19] The method according to claim 18, The predetermined range is achieved when the frequencies of the first and second RF-modified RF signals are the same, by a method. [Application Example 20] The method according to claim 18, The preset range is achieved when the phases of the first and second modified RF signals are the same, in a method.

Claims

1. A first radio frequency (RF) generator having a first operating frequency range of 10 kilohertz (kHz) to 330 kHz, wherein the first RF generator includes a first RF generator configured to generate a first RF signal, A first impedance matching circuit coupled to the first RF generator for receiving the first RF signal, which modifies the impedance of the first RF signal and outputs a first modified RF signal, A plasma chamber configured to receive the first modified RF signal, wherein the plasma chamber includes a first chuck having a first dielectric layer and a base metal layer, the first dielectric layer being located above the base metal layer, the first dielectric layer having a bottom surface, the base metal layer having a porous plug, the bottom surface of the first dielectric layer having a portion in contact with the porous plug, the first dielectric layer having a first thickness smaller than the second thickness of the second dielectric layer of a second chuck configured to be connected to a second radio frequency generator, and the first operating frequency range being smaller than the second operating frequency range of the second radio frequency generator, and the plasma chamber and A system that includes these features.

2. The system according to claim 1, The plasma chamber includes an edge ring surrounding the first chuck, and the system is A third RF generator having a third operating frequency range of 10 kHz to 330 kHz, wherein the third RF generator is configured to generate a second RF signal, A second impedance matching circuit coupled to the third RF generator to receive the second RF signal and modifying the impedance of the second RF signal to output a second modified RF signal. Furthermore, The edge ring is coupled to the second impedance matching circuit and receives the second modified RF signal. system.

3. The system according to claim 2, A host computer coupled to the first and third RF generators, wherein the host computer is The third RF generator is controlled until the frequency of the second modified RF signal falls within a predetermined range from the frequency of the first modified RF signal. The third RF generator is controlled until the phase of the second modified RF signal falls within a preset range from the phase of the first modified RF signal. The third RF generator is controlled to achieve the voltage setpoint. A host computer configured in this way A system that further enhances this feature.

4. The system according to claim 3, The predetermined range is achieved when the frequencies of the operation of the first and second modified RF signals are the same, in a system.

5. The system according to claim 3, The preset range is achieved when the phases of the first and second modified RF signals are the same, in a system.

6. A first radio frequency (RF) generator having an operating frequency range of 10 kilohertz (kHz) to 330 kHz, wherein the first RF generator comprises a first RF generator configured to generate a first RF signal, A first impedance matching circuit coupled to the first RF generator for receiving the first RF signal, which modifies the impedance of the first RF signal and outputs a first modified RF signal, A plasma chamber configured to receive the first modified RF signal, wherein the plasma chamber includes a chuck having a dielectric layer and a base metal layer, the dielectric layer being located above the base metal layer, the dielectric layer having a bottom surface, the base metal layer having a porous plug, and the bottom surface of the dielectric layer having a portion in contact with the porous plug, A second RF generator configured to generate a second RF signal, A host computer coupled to the first and second RF generators, wherein the host computer is Upon receiving an instruction that the first RF generator has been replaced by a third RF generator, the third RF generator has a higher operating frequency than the first RF generator. A voltage signal having the frequency of the first RF signal is received, The voltage signal is divided into a first number of bins, which are different from a second number of bins, and the second number of bins are generated when the third RF generator is used. A host computer configured in such a way A system that further enhances this feature.

7. The system according to claim 1, The system wherein the first dielectric layer excludes porous plugs, and the first operating frequency range is 90 kHz to 110 kHz.

8. Upper electrode and A first chuck facing the upper electrode, wherein the first chuck is A first dielectric layer having a bottom surface, and A base metal layer, wherein the first dielectric layer is located on top of the base metal layer, the base metal layer has a porous plug, and the bottom surface of the first dielectric layer has a portion that contacts the porous plug. Chucks and Equipped with, The first chuck is coupled to a first radio frequency (RF) transmission line and is configured to receive a first modified RF signal having a first frequency in the range of 10 kilohertz (kHz) to 330 kHz. The first dielectric layer has a first thickness that is smaller than the second thickness of the second dielectric layer of a second chuck configured to be connected to a first RF generator having an operating frequency greater than the first frequency. Plasma chamber.

9. A plasma chamber according to claim 8, The first RF transmission line is coupled to a second RF generator via a first impedance matching circuit, and the second RF generator is a plasma chamber having an operating frequency in the range of 10 kHz to 330 kHz.

10. A plasma chamber according to claim 9, Edge electrodes surrounding the first chuck Furthermore, The edge electrode is coupled to a second RF transmission line and configured to receive a second modified RF signal having a frequency in the range of 10 kHz to 330 kHz. Plasma chamber.

11. A plasma chamber according to claim 10, The second RF transmission line is coupled to a third RF generator via a second impedance matching circuit, and the third RF generator is a plasma chamber having an operating frequency in the range of 10 kHz to 330 kHz.

12. A plasma chamber according to claim 11, A plasma chamber in which the phase of the first modified RF signal is within a preset range from the phase of the second modified RF signal.

13. A plasma chamber according to claim 11, A plasma chamber in which the first frequency of the first modified RF signal is within a predetermined range from the second frequency of the second modified RF signal.

14. A plasma chamber according to claim 8, The first dielectric layer excludes a porous plug, the first RF transmission line is coupled to a second RF generator via a first impedance matching circuit, and the second RF generator is a plasma chamber having an operating frequency range of 90 kHz to 110 kHz.

15. The invention relates to generating a first radio frequency (RF) signal, wherein the first RF signal is generated by a first RF generator having a first operating frequency range of 10 kilohertz (kHz) to 330 kHz. The impedance of the first RF signal is corrected, and the first corrected RF signal is output. The first modified RF signal is received through the base metal layer of the first chuck and a portion of the first dielectric layer of the first chuck. Includes, The first dielectric layer is located on top of the base metal layer, The first dielectric layer has a bottom surface, The first dielectric layer has a first thickness that is smaller than the second thickness of the second dielectric layer of a second chuck configured to be connected to a second RF generator having a second operating frequency range, and the second operating frequency range is greater than the first operating frequency range. The base metal layer has a porous plug, and the bottom surface of the first dielectric layer has a portion that contacts the porous plug. method.

16. The method according to claim 15, The first dielectric layer excludes porous plugs, and the first operating frequency range is 90 kHz to 110 kHz.

17. The method according to claim 15, A third RF generator generates a second RF signal, wherein the third RF generator has an operating frequency range of 10 kHz to 330 kHz. The system receives the second RF signal, corrects the impedance of the second RF signal, and outputs a second corrected RF signal. The edge ring receives the second modified RF signal, wherein the edge ring surrounds the first chuck. Methods that further include this.

18. The method according to claim 17, Controlling the second modified RF signal to have a frequency within a predetermined range from the frequency of the first modified RF signal, Controlling the second modified RF signal so that its phase falls within a preset range from the phase of the first modified RF signal, Controlling the third RF generator to achieve the voltage setpoint Methods that further include this.

19. The method according to claim 18, The predetermined range is achieved when the frequencies of the first and second modified RF signals are the same, by means of a method.

20. The method according to claim 18, The preset range is achieved when the phases of the first and second modified RF signals are the same, in a method.

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