Apparatus and method for real-time monitoring of substrate clamping status

Abstract

Systems and methods for determining the real-time clamping status of a substrate on an electrostatic chuck are disclosed. Specifically, the systems and methods involve measuring capacitance to determine whether a substrate is clamped or unclamped. Components of the system can include a matching unit, a bandpass filter, a high voltage power supply, an RF filter, an electrostatic chuck, and a gas distribution device.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing. Specifically, embodiments of this invention relate to a system used in the processing of semiconductor films. Background Technology

[0002] Systems for processing semiconductor films include a substrate holder on which the substrate rests during processing. The substrate holder may include an electrostatic chuck (ESC). The ESC may include electrodes through which a current is applied from a voltage source, causing the substrate to planarize onto the substrate holder. This may be due to the applied current having one polarity (positive or negative), which is attracted to another polarity within the substrate itself. The state of planarizing the substrate onto the substrate holder is called clamping or holding.

[0003] When a substrate is clamped or held, it is possible to process it uniformly. With uniformity, a film of horizontal thickness can be formed. If the substrate is processed without being clamped or held, it may be concave or convex. When processed while the substrate is concave or convex, the resulting film may be non-uniform. This non-uniformity can affect the final performance of the device formed from that substrate. Knowing whether the substrate is clamped or not can help increase yield and prevent loss of processed substrate.

[0004] Electrostatic chucks can be unipolar or bipolar. A unipolar electrostatic chuck has a single electrode to which a single voltage source applies current. A bipolar electrostatic chuck has two electrodes and two voltage sources. The two electrodes of a bipolar electrostatic chuck will have two different polarities of current applied (positive and negative).

[0005] Determining the clamping state can be accomplished by determining the phase shift, as described in U.S. Non-Provisional Patent Application No. 18 / 926,695, filed October 25, 2024, entitled “SUBSTRATE PROCESSING SYSTEM WITH CAPABIILITIES FOR DETECTING WHETHER A WAFERIS DECHUCKED AND A METHOD THEREOF,” which is incorporated herein by reference. Capacitively coupled electrostatic probes can be used to determine the clamping state, as described in U.S. Patent No. 8,780,522, filed July 7, 2009, entitled “CAPACITIVELY-COUPLED ELECTROSTATIC (CCE) PROBE ARRANGEMENT FOR DETECTING DECHUCKING IN A PLASMA PROCESS CHAMBER AND METHODS THEREOF,” which is incorporated herein by reference.

[0006] Bipolar electrostatic chucks have the ability to determine the clamping state regardless of whether plasma is being generated. However, unipolar electrostatic chucks can only determine the clamping state when plasma is being generated. Therefore, there is a need for systems and methods to determine the clamping state in real time, regardless of the state of plasma generation.

[0007] Figure 1 A prior art plasma processing system 100 for determining the clamping state of a monopolar electrostatic chuck is shown. The plasma processing system 100 includes: a matching unit 110; a bandpass filter 120; an electrostatic chuck power supply with a capacitance measurement circuit 130; an RF filter 140; a base with at least two capacitors 150; and a plasma switch 160. The bandpass filter 120 protects the components of the system from power loss due to the RF power applied to the spray head.

[0008] When plasma switch 160 is turned on, plasma processing system 100 can measure the clamping state by the difference in readings of two capacitors within base 150. The clamping state is determined by measuring the shift in impedance when the substrate is on the base relative to the impedance when the substrate is off the base. This can be achieved by synchronizing the capacitance measurement with the RF power-on timing or by averaging the total capacitance over time during plasma on and off states.

[0009] However, if the plasma switch 160 is open, the plasma processing system 100 cannot determine the clamping state of the substrate. Therefore, a system capable of determining the clamping state regardless of whether the plasma switch is on or off is desired.

[0010] Any discussion set forth in this section (including discussions of problems and solutions) is included in this disclosure for the purpose of providing background information and should not be construed as an admission that any or all of the discussions were known at the time of making this invention or otherwise constitute prior art. Summary of the Invention

[0011] In at least one embodiment of the present invention, a processing system for a semiconductor substrate is disclosed. The processing system includes: a reaction chamber; a gas distribution device disposed within the reaction chamber, the gas distribution device including a first electrode and configured to distribute gas onto the substrate and generate a first capacitance detection frequency signal; an electrostatic chuck disposed within the reaction chamber and configured to hold the substrate for processing; a second electrode disposed within the electrostatic chuck and configured to generate a second capacitance detection frequency signal; a high-voltage power supply disposed outside the reaction chamber, the high-voltage power supply configured to monitor the first capacitance detection frequency signal and the second capacitance detection frequency signal to determine a frequency phase shift and calculate capacitance based on the frequency phase shift, wherein the high-voltage power supply is configured to provide a first power signal to the second electrode; an RF filter configured to filter the power signal to the second electrode and configured to provide the second capacitance detection frequency signal to the high-voltage power supply; and a bandpass filter configured to provide the first capacitance detection frequency signal to the high-voltage power supply; wherein the capacitance from the frequency phase shift indicates the real-time clamping state of the substrate.

[0012] In at least one embodiment of the present invention, a method for determining the clamping state of a substrate is disclosed. The method includes: providing a substrate in a processing system, the processing system including: a reaction chamber; a gas distribution device disposed in the reaction chamber, the gas distribution device including a first electrode and configured to distribute gas onto the substrate and generate a first capacitance detection frequency signal; an electrostatic chuck disposed in the reaction chamber and configured to hold the substrate for processing; a second electrode disposed in the electrostatic chuck and configured to generate a second capacitance detection frequency signal; a high-voltage power supply disposed outside the reaction chamber, the high-voltage power supply configured to monitor the first capacitance detection frequency signal and the second capacitance detection frequency signal to determine a frequency phase shift and calculate capacitance based on the frequency phase shift, wherein the high-voltage power supply is configured to provide a first power signal to the second electrode; an RF filter configured to filter the power signal to the second electrode and configured to provide the second capacitance detection frequency signal to the high-voltage power supply; and a bandpass filter configured to provide the first capacitance detection frequency signal to the high-voltage power supply; a pulse from the first power signal from the high-voltage power supply; and monitoring capacitance based on the frequency phase shift to indicate the real-time clamping state of the substrate.

[0013] For the purpose of summarizing the invention and its advantages relative to the prior art, certain objects and advantages of the invention have been described above. It should be understood, of course, that not all of these objects or advantages may necessarily be achieved according to any particular embodiment of the invention. Therefore, for example, those skilled in the art will recognize that the invention may be embodied or implemented in a manner that achieves or optimizes one or more advantages taught or suggested herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0014] All these embodiments are intended to fall within the scope of the invention disclosed herein. Those skilled in the art will readily appreciate these and other embodiments from the following detailed description of certain embodiments with reference to the accompanying drawings; however, the invention is not limited to any particular embodiment disclosed. Attached Figure Description

[0015] These and other features, aspects, and advantages of the invention disclosed herein are described below with reference to the accompanying drawings of certain embodiments, which are intended to illustrate rather than limit the invention.

[0016] Figure 1 It is a circuit diagram of an existing technology system.

[0017] Figure 2 This is a schematic diagram of a semiconductor manufacturing system according to at least one embodiment of the present invention.

[0018] Figure 3 This is a signal diagram according to at least one embodiment of the present invention.

[0019] Figure 4 This is a capacitance signal diagram according to at least one embodiment of the present invention.

[0020] It should be understood that the elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements to aid in understanding the embodiments shown in this disclosure. Detailed Implementation

[0021] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specific embodiments and / or uses disclosed herein, as well as their obvious modifications and equivalents. Therefore, the scope of the invention disclosed herein should not be limited to the specific embodiments described below.

[0022] As used herein, the term "substrate" can refer to any one or more underlying materials, including any one or more underlying materials that can be modified or on which devices, circuits, or films can be formed. A "substrate" can be continuous or discontinuous; rigid or flexible; solid or porous; and combinations thereof. A substrate can be in any form, such as powder, plate, or workpiece. Plate-type substrates can include wafers of various shapes and sizes. Substrates can be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0023] In this disclosure, "gas" can include materials that are gaseous at room temperature and pressure, evaporated solids and / or evaporated liquids, and may consist of a single gas or a mixture of gases, depending on the circumstances. Gases introduced without passing through a gas supply unit (e.g., a spray plate, etc.) can be used, for example, to seal the reaction space, and may include sealing gases, such as rare gases or other inert gases. The terms inert gas, carrier gas, and diluent gas refer to gases that do not participate in the chemical reaction to a perceptible extent and / or gases that can excite precursors when plasma power is applied.

[0024] As used herein, the terms “membrane” and “thin film” can refer to any continuous or discontinuous structure and material deposited by the methods disclosed herein. For example, “membrane” and “thin film” can include 2D materials, nanorods, nanotubes, or nanoparticles, or even partial or complete molecular layers, or partial or complete atomic layers, or atomic and / or molecular clusters. “Membrane” and “thin film” can include materials or layers with pinholes, but still at least partially continuous.

[0025] The illustrations presented herein are not intended to be actual views of any particular material, structure, or device, but are merely idealized representations used to describe embodiments of this disclosure.

[0026] The specific embodiments shown and described are illustrative of the invention and its best mode, and are not intended to limit the scope of aspects and embodiments in any way. In fact, for the sake of brevity, conventional manufacturing, connection, fabrication, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the 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 the actual system, and / or may not exist in some embodiments.

[0027] It should be understood that the configurations and / or methods described herein are exemplary in nature, and these specific embodiments or examples herein should not be considered limiting, as many variations are possible. The particular routines or methods described herein may represent one or more of any number of processing strategies. Therefore, the various actions shown may be performed in the order shown, in another order, or in some cases omitted.

[0028] The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of various processes, systems and configurations, as well as other features, functions, actions and / or properties disclosed herein, and any and all equivalents thereof.

[0029] Figure 2A plasma processing system 200 according to at least one embodiment of the present invention is shown. The plasma processing system 200 may include a reaction chamber 210, which includes a gas distributor 215, an electrostatic chuck 220 configured to hold a substrate 225, and electrodes 230 disposed within the electrostatic chuck 220. The gas distributor 215 may be configured to uniformly flow gas onto the substrate 225. Additionally, the gas distributor 215 may be configured to act as an electrode and generate a first capacitance detection frequency signal. The electrodes 230 may generate a second capacitance detection frequency signal.

[0030] Plasma 235 can be generated from the gas in reaction chamber 210 by applying power generated by RF generator 240. Plasma 235 can then be used to process substrate 225 by plasma-enhanced atomic layer deposition (PEALD), plasma-enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), sputtering, or etching processes.

[0031] The plasma processing system 200 may further include: an RF signal generator 240; a matching unit 250; a bandpass filter 260; a high-voltage power supply 270 with capacitance monitoring; and an RF filter 280. As previously described, the RF generator 240 generates RF power for forming plasma from a gas flowing in the reaction chamber 210. The matching unit 250 may be configured to adjust the impedance of the reaction chamber 210 to make the generated RF power more efficient in wafer processing.

[0032] The bandpass filter 260 can be configured to allow a first capacitance-detected frequency signal measurement from the gas distributor 215 to pass through to the high-voltage power supply 270. The distance between the bandpass filter 260 and the gas distributor 215 can be reduced to match the supply frequency wavelength, thereby reducing power loss in the connection between the gas distributor 215 and the bandpass filter 260.

[0033] The capacitance measurement determined at the high-voltage power supply 270 can indicate the clamping state of the substrate 225. The capacitance measurement can be determined by detecting the frequency phase shift between the first capacitance detection frequency signal and the second capacitance detection frequency signal.

[0034] Capacitance measurement can be a function as shown in the following equation, where C is the capacitance in farads, ε is the absolute permittivity of the dielectric, A is the overlapping area of ​​the plates in square meters, and d is the distance between the plates in meters.

[0035] [I]

[0036] Due to the distance between the substrate and the top surface of the electrostatic chuck 220, the capacitance of the clamped substrate 225 may differ from the capacitance of the unclamped substrate.

[0037] The high-voltage power supply 270 can then regulate the HRF power supplied to the electrodes 230 in the electrostatic chuck 220 via the RF filter 280. The RF filter 280 isolates the high-voltage power supply 270 from the HRF power from the RF generator 240.

[0038] Figure 3 A signal waveform diagram of a substrate or wafer according to at least one embodiment of the present invention is shown. Depending on the state of the HRF power generated by the high-voltage power supply 270, the measured capacitance may vary depending on whether the substrate 225 is bent or flat, clamped or not.

[0039] When the bent substrate is not clamped, an unclamped bent substrate capacitance signal waveform 310 can be generated. When the HRF power switches between on and off states, the unclamped bent substrate capacitance signal waveform 310 can switch only between a low signal and an intermediate baseline signal.

[0040] When the bent substrate is clamped, a bent substrate capacitance signal waveform 320 is generated. When the HRF power switches between on and off states, the bent substrate capacitance signal waveform 320 can switch between low and high signals.

[0041] When a flat substrate is clamped, a clamped flat substrate capacitance signal waveform 330 is generated. When the HRF power switches between on and off states, the clamped curved substrate capacitance signal waveform 330 can switch between low and high signals. The clamped curved substrate capacitance signal waveforms 320 and 330 may not differ significantly because both wafers are flat.

[0042] The clamping state is determined by comparing the capacitance signal waveform of the clamped substrate with the capacitance signal waveform 330 of the flat substrate. If they match, the system continues operation. However, if they do not match, the system will issue an alarm indicating that the substrate is not clamped.

[0043] Figure 4 A signal waveform diagram of a substrate or wafer according to at least one embodiment of the present invention is shown. When the substrate 225 is clamped, a capacitance signal waveform 410 is generated, wherein the capacitance varies between a low signal and a high signal. When the substrate 225 is not clamped, a capacitance signal waveform 420 is generated, wherein the capacitance varies between a low signal and an intermediate signal. As shown in equation [I], when the substrate is not clamped, the overlap area A between the substrate and the pedestal decreases; therefore, as a result, the total capacitance C may decrease.

[0044] A decrease in the capacitance signal indicates that the substrate is not clamped. Using this knowledge, substrate processing can be paused to allow the substrate to be planarized. Properly planarized substrates can then lead to the formation of suitable films on the substrate.

[0045] The specific embodiments shown and described are illustrative of the invention and its best mode, and are not intended to limit the scope of aspects and embodiments in any way. In fact, for the sake of brevity, conventional manufacturing, connection, fabrication, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the 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 the actual system, and / or may not exist in some embodiments.

[0046] It should be understood that the configurations and / or methods described herein are exemplary in nature, and these specific embodiments or examples herein should not be considered limiting, as many variations are possible. The particular routines or methods described herein may represent one or more of any number of processing strategies. Therefore, the various actions shown may be performed in the order shown, in another order, or in some cases omitted.

[0047] The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of various processes, systems and configurations, as well as other features, functions, actions and / or properties disclosed herein, and any and all equivalents thereof.

Claims

1. A processing system for a semiconductor substrate, wherein, The processing system includes: Reaction chamber; A gas distribution device is disposed in a reaction chamber. The gas distribution device includes a first electrode and is configured to distribute gas onto a substrate and generate a first capacitance detection frequency signal. An electrostatic chuck is disposed in the reaction chamber and configured to hold the substrate for processing; The second electrode is disposed in the electrostatic chuck and configured to generate a second capacitance detection frequency signal; A high-voltage power supply is located outside the reaction chamber. The high-voltage power supply is configured to monitor the frequency signals of the first capacitor and the second capacitor to determine the frequency phase shift and calculate the capacitance based on the frequency phase shift. The high-voltage power supply is configured to provide a first power signal to the second electrode. An RF filter configured to filter the power signal to the second electrode and configured to provide a second capacitor detection frequency signal to the high-voltage power supply; and A bandpass filter configured to provide a first capacitor detection frequency signal to a high-voltage power supply; The capacitance derived from the frequency phase shift indicates the real-time clamping state of the substrate.

2. The processing system according to claim 1 further includes a matching unit configured to adjust the impedance of the reaction chamber.

3. The processing system according to claim 2 further includes an RF generator coupled to the matching unit, wherein, The RF generator is configured to provide a second power signal to the first electrode via a matching unit.

4. The processing system according to claim 1, wherein, The RF filter is configured to tune the impedance of the RF filter.

5. The processing system according to claim 1, wherein, Plasma is generated between the gas distribution device and the electrostatic chuck.

6. The processing system according to claim 1, wherein, The real-time clamping status indicates whether the substrate is clamped or not.

7. A method for determining the clamping state of a substrate, the method comprising: A substrate is provided in the processing system, which includes: Reaction chamber; A gas distribution device is disposed in a reaction chamber. The gas distribution device includes a first electrode and is configured to distribute gas onto a substrate and generate a first capacitance detection frequency signal. An electrostatic chuck is disposed in the reaction chamber and configured to hold the substrate for processing; The second electrode is disposed in the electrostatic chuck and configured to generate a second capacitance detection frequency signal; A high-voltage power supply is located outside the reaction chamber. The high-voltage power supply is configured to monitor the frequency signals of the first capacitor and the second capacitor to determine the frequency phase shift and calculate the capacitance based on the frequency phase shift. The high-voltage power supply is configured to provide a first power signal to the second electrode. An RF filter configured to filter the power signal to the second electrode and configured to provide a second capacitor detection frequency signal to the high-voltage power supply; and A bandpass filter configured to provide a first capacitor detection frequency signal to a high-voltage power supply; The pulse originates from the first power signal of the high-voltage power supply; and The frequency phase shift monitoring capacitor is used to indicate the real-time clamping status of the substrate.

8. The method according to claim 7, wherein, The processing system also includes a matching unit configured to adjust the impedance of the reaction chamber.

9. The method according to claim 7, wherein, The processing system further includes an RF generator coupled to the matching unit, wherein the RF generator is configured to provide a second power signal to the first electrode via the matching unit.

10. The method according to claim 7, wherein, The RF filter is configured to tune the impedance of the RF filter.

11. The method according to claim 7, wherein, Plasma is generated between the gas distribution device and the electrostatic chuck.

12. The method according to claim 7, wherein, The real-time clamping status indicates whether the substrate is clamped or not.

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