Plasma modulation apparatus for substrate processing system

Abstract

A plasma modulation apparatus for a substrate processing system is disclosed. The apparatus includes a plurality of radio frequency (RF) paths connected to N different grids, where a susceptor of a substrate processing system is divided into N different grids, N is an integer equal to or greater than 2, where each RF path includes: an RF rod connected to the grid and configured to transmit an RF signal from the grid; a voltage-current (VI) sensor connected to the RF bar and configured to measure a current from the RF bar; and a variable impedance circuit connected to the VI sensor and configured to change the impedance of the RF paths and further configured to ground, where each RF path is individually grounded and each RF path corresponds to a different grid, respectively.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing system, and more particularly, to an apparatus for modulating a plasma environment within a reaction chamber of a substrate processing system. Background Art

[0002] The deposition and sputtering uniformity on the wafer is closely related to the plasma distribution, such as the density in the reaction chamber. In the plasma enhanced atomic layer deposition (PEALD) process, any non-uniformity of the plasma distribution directly affects the deposition and sputtering uniformity on the wafer.

[0003] The present disclosure provides a plasma conditioning hardware that can address non-uniformity issues across a wafer during a PEALD or sputtering process.

[0004] The present disclosure provides an apparatus for achieving deposition and sputtering uniformity across a wafer by modulating the impedance of a radio frequency (RF) return path to ground. Summary of the invention

[0005] This summary is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the detailed description of the example embodiments disclosed below. This summary is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0006] According to one embodiment, a plasma modulation device for a substrate processing system may be provided, the device comprising: a plurality of radio frequency (RF) paths connected to N different grids, wherein a base of the substrate processing system is divided into N different grids, N being an integer equal to or greater than 2, wherein each RF path comprises: an RF rod connected to the grid and configured to transmit an RF signal from the grid; a voltage-current (VI) sensor connected to the RF rod and configured to measure a current from the RF rod; and a variable impedance circuit connected to the VI sensor and configured to change an impedance of the RF path and further configured to be grounded, and wherein each RF path is grounded individually and each RF path corresponds to a different grid, respectively.

[0007] According to another embodiment, it may be provided that the device further comprises: an RF filter configured to filter out noise from the RF rod.

[0008] According to another embodiment, it may be provided that the device further comprises: a controller which is coupled to each RF path and is configured to monitor the current of each VI sensor and to change the impedance of each RF path based on the monitored current.

[0009] In at least one aspect, the controller is configured to change the impedance of each RF path to be equal.

[0010] According to another embodiment, it can be provided that a substrate processing system includes: a reaction chamber provided with a showerhead and a susceptor for supporting a wafer, the susceptor being divided into N different grids, wherein N is an integer equal to or greater than 2; and a plasma modulation device including: a plurality of radio frequency (RF) paths connected to the N different grids, wherein each RF path includes: an RF rod connected to the grid and configured to transmit an RF signal from the grid; a voltage-current (VI) sensor connected to the RF rod and configured to measure a current from the RF rod; and a variable impedance circuit connected to the VI sensor and configured to change an impedance of the RF path and further configured to be grounded, and wherein each RF path is individually grounded and each RF path corresponds to a different grid, respectively.

[0011] According to another embodiment, it may be provided that the system further comprises: an RF filter configured to filter out noise from the RF rod.

[0012] According to another embodiment, it may be provided that the system further comprises: a controller connected to each RF path and configured to monitor the current of each VI sensor and to change the impedance of each RF path based on the monitored current.

[0013] In at least one aspect, a controller of the system is configured to change the impedance of each RF path to be equal.

[0014] According to another embodiment, it can be provided that a method of modulating plasma in a substrate processing system includes a reaction chamber provided with a susceptor, the susceptor being divided into N different grids, where N is an integer equal to or greater than 2, and a plasma modulation device, the plasma modulation device including a plurality of radio frequency (RF) paths connected to the N different grids, and each RF path is provided with an RF rod, a voltage-current (VI) sensor, and a variable impedance circuit, the method including: monitoring currents of all VI sensors from corresponding RF paths; determining whether it is true that the monitored currents have the same value; and if the determination is false, changing the impedances of the variable impedance circuits from the corresponding RF paths to be equal, and if the determination is true, repeating the determination.

[0015] In at least one aspect, the method further comprises filtering noise from each RF rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure.

[0017] Figure 1A top view of a pedestal (heater) having 3 grids is shown according to an embodiment of the present disclosure.

[0018] Figure 2 A system overview of a substrate processing system according to an embodiment of the present disclosure is shown.

[0019] Figure 3 Detailed views of three grids of a pedestal and plasma distribution in a reaction chamber are shown according to an embodiment of the present disclosure.

[0020] Figure 4 A detailed view of a plasma modulation apparatus according to an embodiment of the present disclosure is shown.

[0021] Figure 5 A flow chart of a plasma modulation method according to another embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0022] Although certain embodiments and examples are disclosed below, those skilled in the art will appreciate that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specifically disclosed embodiments described below.

[0023] As used herein, the term "substrate" may refer to any one or more underlying materials, including any one or more underlying materials that may be modified or on which a device, circuit, or film may be formed. A "substrate" may be continuous or non-continuous; rigid or flexible; solid or porous; and combinations thereof. A substrate may be in any form, such as a powder, a plate, or a workpiece. A plate-like substrate may include wafers of various shapes and sizes. A substrate may be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0024] For example, a substrate in powder form can be used in drug manufacturing. The porous substrate can include a polymer. Examples of workpieces can include medical devices (such as stents and syringes), jewelry, tool equipment, components for battery manufacturing (such as anodes, cathodes, or separators), or components of photovoltaic cells, etc.

[0025] The continuous substrate may extend beyond the boundaries of the processing chamber in which the deposition process occurs. In some processes, the continuous substrate may be moved through the processing chamber so that the process continues until the end of the substrate is reached. The continuous substrate may be provided from a continuous substrate feed system to allow the continuous substrate to be manufactured and output in any suitable form.

[0026] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, meshes, flexible materials, bundles of continuous filaments or fibers (eg, ceramic fibers or polymer fibers).The continuous substrate may also include a carrier or sheet on which a discontinuous substrate is mounted.

[0027] The illustrations presented herein are not meant to be actual views of any particular material, structure, or device but are merely idealized representations used to describe embodiments of the present disclosure.

[0028] The specific embodiments shown and described are illustrations of the present invention and its best mode and are not intended to limit the scope of these aspects and embodiments in any way. In fact, for the sake of brevity, the traditional manufacturing, connection, preparation and other functional aspects of the system may not be described in detail. In addition, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical connections between various elements. Many alternative or additional functional relationships or physical connections may exist in actual systems, and / or may not exist in some embodiments.

[0029] It should be understood that the configuration and / or method described herein are exemplary in nature, and these specific embodiments or examples should not be considered restrictive, because many variations are possible. The specific routine or method described herein can represent one or more of any number of processing strategies. Therefore, the various actions shown can be performed in the order shown, in other orders, or omitted in some cases.

[0030] The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts and / or properties disclosed herein, and any and all equivalents thereof.

[0031] exist Figure 1 , the base 100 can be shown in detail. The base 100 can be divided into 3 areas (grids), such as a background grid (grid #1) 110, a left grid (grid #2) 120, and a right grid (grid #3) 130. Alternatively, the heater can be the target of the grid division in response to system requirements.

[0032] Figure 2 An overview of the present disclosure is shown.

[0033] The substrate processing system 200 may include a reaction chamber 201 having a showerhead 213, a susceptor 216, a heater coil 217, an RF generator 210, and a matcher unit 211, as well as a plasma modulation device 224 and a controller 225. Between the showerhead 213 and the susceptor 216, a space 214 may be formed for generated plasma, and a wafer 215 may be placed on the susceptor 216 so that the wafer 215 may be processed with plasma and a reactant gas (not shown).

[0034] The top of the base 216 may be divided into a plurality of different grids, and for simplicity, three grids may be used in the explanation of the present disclosure.

[0035] and Figure 1 Like the base 100 in FIG. 2 , the base 216 can be divided into three grids 221 , 222 , 223 . Each grid 221 , 222 , 223 is connected to a plasma modulation device 224 via three RF rods 231 , 232 , 233 .

[0036] Figure 3 and 4 Different aspects of the system and equipment are explained in more detail.

[0037] Figure 3 A detailed view of a reaction chamber 300 and three grids 321, 322, 323 containing a space 314 in which plasma is distributed and a susceptor 316 are shown. In this reaction chamber 300 of a substrate processing system, plasma in the space 314 can be generated between an upper electrode (showerhead) 313 and a lower electrode (susceptor) 316. A wafer 315 can be placed on the susceptor 316.

[0038] In order to adjust the plasma distribution in the space 314, the pedestal 316 may be divided into a plurality of regions. Figure 3 As shown, the number of divided regions of the base 316 will be 3. However, there may be more than 3 regions as required. The base 316 may include different grids 321, 322, 323. The three grids 321, 322, 323 may be placed just below the surface of the base 316. Alternatively, the grids may be placed on the surface of the base 316 based on system requirements.

[0039] The left grid (grid #2) 322 may be mainly affected by the plasma distribution (P2) directly above it, while the right grid (grid #3) 323 is affected by the plasma distribution (P3). In addition, the background grid (grid #1) 321 may be affected by the plasma distribution (P1). Each grid 321, 322, 323 can be connected to an RF rod 331, 332, 333, respectively.

[0040] Figure 4 A plasma modulation device according to an embodiment of the present disclosure is shown.

[0041] A plurality of RF rods 401, 402, 403 are attached to grids #1, #2, #3, respectively. Each RF rod can be connected to a VI sensor (voltage-current sensor) 451, 452, 453, which can measure the voltage and current of the plasma transmitted from the grid.

[0042] The VI sensor 451 may be connected to a variable impedance circuit 441, which may change the impedance of an electrical path established from the RF rod 401 to the ground 461, and the variable impedance circuit 441 may include at least one of a coil, a capacitor, or a variable capacitor for changing the impedance. The variable impedance circuit 441 is grounded to the ground 461. In the VI sensor 451, a current (i1) may be measured and the current reflects the plasma distribution (P1).

[0043] The VI sensor 452 may be connected to a variable impedance circuit 442, which may change the impedance of an electrical path established from the RF rod 402 to the ground 462, and the variable impedance circuit 442 may include at least one of a coil, a capacitor, or a variable capacitor for changing the impedance. The variable impedance circuit 442 is grounded to the ground 462. In the VI sensor 452, a current (i2) may be measured, and the current reflects the plasma distribution (P2).

[0044] The VI sensor 453 may be connected to a variable impedance circuit 443, which may change the impedance of an electrical path established from the RF rod 403 to the ground 463, and the variable impedance circuit 443 may include at least one of a coil, a capacitor, or a variable capacitor for changing the impedance. The variable impedance circuit 443 is grounded to the ground 463. In the VI sensor 453, a current (i3) may be measured and the current reflects the plasma distribution (P3).

[0045] The plasma uniformity in the reaction chamber 300 may be expressed as “P1=P2=P3” (condition 1).

[0046] In order to make the plasma distribution in the chamber uniform (ie, P1=P2=P3), the currents measured in the VI sensors 451, 452, 453 should be the same. Therefore, by changing the impedance of the variable impedance circuits 441, 442, 443, the currents i1, i2, i3 can be adjusted to be the same as each other.

[0047] The same current of i1, i2, i3 can be expressed as "i1=i2=i3" (condition 2), and if "condition 1" (P1=P2=P3) is satisfied, "condition 2" (i1=i2=i3) is satisfied.

[0048] There may be more than one path from the grid to the ground (e.g. Figure 4 As shown), each path may be referred to as an RF path. Therefore, the number of RF paths may be equal to the number of grids. As an example, Figure 4There are three RF paths in the embodiment. RF path #1 may include RF rod 401, VI sensor 451, and variable impedance circuit 441. RF path #2 may include RF rod 402, VI sensor 452, and variable impedance circuit 442. RF path #3 may include RF rod 403, VI sensor 453, and variable impedance circuit 443. RF path #1 may terminate at ground 461. RF path #2 may terminate at ground 462. RF path #3 may terminate at ground 463.

[0049] The plasma modulation device 400 may include N RF paths, where N is the number of grids, and N is equal to or greater than 2. In addition, the device 400 may further include an RF filter 450 and a controller 425 .

[0050] The impedance change of the variable impedance circuits 441 , 442 , 443 may be performed manually or automatically.

[0051] In order to automatically change the impedance, the current of the VI sensors 451, 452, 453 should be continuously monitored. This can be achieved by connecting the controller 425 to each RF path, in particular to the VI sensors and the variable impedance circuit. The controller 425 can monitor the VI sensors 451, 452, 453. When the measured currents i1, i2, i3 become different from each other, the controller 425 can adjust the impedance of the circuits 441, 442, 443. The controller 425 can adjust the circuits 441, 442, 443 to meet "Condition 2" (i1=i2=i3).

[0052] RF filter 450 may be disposed in RF rods 401, 402, 403. RF filter 450 may filter noise from signals in RF rods 401, 402, 403 so that each signal entering VI sensors 451, 452, 453 may be clear for better current measurement in each VI sensor.

[0053] In the present disclosure, the number of meshes and the number of RF paths may be 3, but the number may vary according to conditions and requirements of the system.

[0054] Figure 5 A plasma modulation method according to another embodiment of the present disclosure is shown.

[0055] The controller 425 can continuously monitor each RF rod 401, 402, 403. This means that the controller 425 can monitor the current (i1, i2, i3) of the VI sensor (451, 452, 453) respectively (512). Given the monitored current values, the controller 425 can compare the current values ​​and can determine whether the monitored currents are the same or not (513).

[0056] If the determination is likely false, the controller 425 may change the impedances of the variable impedance circuits to be equal to each other, and if true, the controller 425 keeps monitoring the current of the VI sensor (514).

[0057] Prior to monitoring, the RF filter 450 will be used to filter out noise from the corresponding RF rod for better signal measurement in the VI sensor (511).

[0058] The arrangement of the above-mentioned devices is only an illustration of the application of the principles of the present invention, and many other embodiments and modifications may be made without departing from the spirit and scope of the present invention defined in the claims. Therefore, the scope of the present invention should not be determined with reference to the above description, but with reference to the full scope of the appended claims and their equivalents.

Claims

1. A plasma modulation device for a substrate processing system, the device comprising: a plurality of radio frequency (RF) paths connected to N different grids, wherein the pedestal of the substrate processing system is divided into the N different grids, N being an integer equal to or greater than 2, Each RF path includes: an RF pole connected to one of the N different grids and configured to transmit an RF signal from the connected grid; a voltage-current (VI) sensor connected to the RF rod and configured to measure current from the RF rod; and a variable impedance circuit connected to the VI sensor and configured to change the impedance of the RF path and further configured to be grounded, Each RF path is grounded separately, and each RF path corresponds to a different grid.

2. The apparatus according to claim 1, further comprising: An RF filter is configured to filter out noise from the RF rod.

3. The plasma modulation device according to any one of claims 1 to 2, further comprising: A controller is coupled to each RF path and configured to monitor a current of each VI sensor and to change an impedance of each RF path based on the monitored current.

4. The plasma modulation device according to claim 3, wherein: The controller is configured to change impedances of the plurality of RF paths to be equal to each other.

5. A substrate processing system, comprising: A reaction chamber provided with a showerhead and a susceptor for supporting a wafer, the susceptor being divided into N different grids, where N is an integer equal to or greater than 2; and A plasma modulation device, comprising: Multiple radio frequency (RF) paths connected to N different grids, Each RF path includes: an RF pole connected to one of the N different grids and configured to transmit an RF signal from the connected grid; a voltage-current (VI) sensor connected to the RF rod and configured to measure current from the RF rod; and a variable impedance circuit connected to the VI sensor and configured to change the impedance of the RF path and further configured to be grounded, and Each RF path is grounded separately, and each RF path corresponds to a different grid.

6. The substrate processing system according to claim 5, further comprising: An RF filter is configured to filter out noise from the RF rod.

7. The substrate processing system according to any one of claims 5 to 6, further comprising: A controller is connected to each RF path and is configured to monitor the current of each VI sensor and change the impedance of each RF path based on the monitored current.

8. The substrate processing system according to claim 7, wherein: The controller is configured to change impedances of the plurality of RF paths to be equal to each other.

9. A method of modulating plasma in a substrate processing system, the system comprising a reaction chamber provided with a susceptor, the susceptor being divided into N different grids, wherein N is an integer equal to or greater than 2, and a plasma modulation device, the plasma modulation device comprising a plurality of radio frequency (RF) paths connected to the N different grids, and each RF path being provided with an RF rod, a voltage-current (VI) sensor, and a variable impedance circuit, the method comprising: Monitor the current of all VI sensors from the corresponding RF paths; determining whether it is true that the monitored currents have the same value; as well as If the determination is false, the impedances of the variable impedance circuits from the corresponding RF paths are changed to be equal, and if the determination is true, the determination is repeated.

10. The method of modulating plasma according to claim 9, further comprising: The noise from each RF rod is filtered out.

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