Substrate processing system with capabilities for detecting whether wafer is dechucked and method thereof

Abstract

To provide a substrate processing system with capabilities to detect whether a wafer is dechucked during a process.SOLUTION: An embodiment of the system disclosed herein comprises: a reaction chamber provided with an upper electrode and a lower electrode and configured to process a wafer; a radio frequency generator configured to generate a high-frequency power to process the wafer in the reaction chamber; a matching unit disposed between the reaction chamber and the generator and configured to match the generated high frequency power from the generator for use in the reaction chamber; a phase shift detector connected to the reaction chamber in parallel and configured to detect a phase shift between a signal going into the upper electrode and a signal coming out of the lower electrode; and a controller connected to the phase shift detector and configured to receive parameters and to determine and display the status of the wafer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to substrate processing systems, and more particularly to substrate processing systems having the capability to detect whether a currently being processed wafer has been dechucked without any interference with the process. [Background technology]

[0002] During the deposition process, the silicon wafer may occasionally be dechucked (detached from the silicon wafer holder) due to insufficient chucking force or perturbations in the plasma parameters, which can result in poor film uniformity and reduced yield.

[0003] By observing the reflected power of low radio frequency (LRF) in plasma enhanced chemical vapor deposition (PECVD) process, unchuck events (meaning an event where a wafer placed on a holder in a deposition device is removed from the holder from the beginning of the process) and dechuck events (meaning an event when a wafer is removed from the holder during the process) can be detected during the deposition stage. However, plasma enhanced atomic layer deposition (PEALD) process does not have an LRF module, so it would be impossible to detect a bad chuck during PEALD process using the method used in PECVD process.

[0004] Therefore, there is a need for a system and method for detecting whether a wafer in a system is dechucked (or unchucked) during a PEALD process. Summary of the Invention

[0005] This Summary is provided to introduce a selection of concepts in a simplified form that are described in further detail below in the Detailed Description of Example Embodiments of the Disclosure. This Summary is not intended to identify key 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, there may be provided a substrate processing system capable of detecting whether a wafer is in a dechucked state during processing, the substrate processing system comprising: a reaction chamber configured to process a wafer, the reaction chamber comprising an upper electrode and a lower electrode; a radio frequency (RF) generator configured to generate radio frequency power in the reaction chamber; a matching unit disposed between the reaction chamber and the RF generator and configured to adjust the impedance of the reaction chamber such that the generated radio frequency power is more effective in processing; a phase shift detector connected in parallel to the reaction chamber and configured to detect a phase shift between a signal input to the upper electrode and a signal output from the lower electrode; and a controller connected to the phase shift detector and configured to receive a parameter to determine and display a chucked state of the wafer.

[0007] In at least one embodiment, the substrate processing system further comprises a first attenuator disposed between the upper electrode and the phase shift detector, and a second attenuator disposed between the phase shift detector and the lower electrode.

[0008] According to another embodiment, there may be provided a method for detecting whether a wafer is in a dechucked state in a substrate processing system, the method including receiving a first threshold, a second threshold, and a minimum amount of time; measuring a degree of phase shift from upper and lower electrodes of a reaction chamber; determining whether it is true that the measured degree of phase shift is not within the first and second thresholds and has lasted for longer than the minimum amount of time; indicating a dechucked state if determined to be true; and repeating the measurement if determined to be false.

[0009] According to another embodiment, there may be provided a substrate processing system having the capability of detecting whether a wafer is in a dechucked state during processing, the substrate processing system comprising: a reaction chamber having an upper electrode and a lower electrode and configured to process a wafer; a radio frequency (RF) generator configured to generate a radio frequency signal to process the wafer in the reaction chamber; a matching unit disposed between the reaction chamber and the RF generator and configured to adjust the impedance of the reaction chamber such that the generated radio frequency power is more effective in processing; a network analysis unit connected in parallel to the reaction chamber and configured to detect a transmission coefficient of the reaction chamber; and a controller connected to the network analysis unit and configured to receive the parameters to determine and indicate the dechucked state of the wafer.

[0010] In at least one embodiment, the substrate processing system further includes a first low pass filter (LPF) disposed between the upper electrode and the network analysis unit, and a second LPF disposed between the network analysis unit and the lower electrode.

[0011] In at least one embodiment, the network analysis unit is a vector network analyzer.

[0012] In at least one embodiment, the transmission coefficient is calculated according to the following formula: S 21 =S out / S in , (S 21 : Transmission coefficient, S out : The signal output from the first LPF, S in : the signal input to the second LPF).

[0013] According to another embodiment, there may be provided a method for detecting whether a wafer is dechucked in a substrate processing system, the method including receiving a threshold value, measuring a transmission coefficient from a reaction chamber, determining whether it is true that the measured transmission coefficient is greater than the threshold value, indicating a dechuck condition if determined to be true, and repeating the measuring step if determined to be false.

[0014] According to another embodiment, there may be provided a substrate processing system having the capability of detecting whether a wafer is dechucked during processing, the substrate processing system comprising: a reaction chamber configured to process a wafer; a radio frequency (RF) generator configured to generate radio frequency power for processing the wafer in the reaction chamber; a matching unit disposed between the reaction chamber and the RF generator and configured to adjust an impedance of the reaction chamber such that the generated radio frequency power is more effective in processing; a screening circuit connected in series to the matching unit and configured to generate a reference voltage that is used to calculate a tilt value (b) to determine whether the wafer is dechucked; and a controller connected to the screening circuit and configured to monitor the reference voltage, calculate the tilt value, and determine whether the wafer is dechucked.

[0015] In at least one embodiment, the substrate processing system includes a screen circuit comprising two or more resistors, two or more capacitors, one or more coils, and one or more diodes.

[0016] According to another embodiment, a method for detecting whether a wafer is dechucked in a substrate processing system includes receiving a predetermined number (N) and a threshold value, and detecting N reference voltages (V) from a screening circuit (1≦i≦N). ref、i ) and N reference voltages (V ref、i ) (1≦i≦N) and calculate the moving average value y n (1≦n≦N),

number

number

[0017] It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale, for example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the illustrated embodiments of the present disclosure.

[0018] [Figure 1] FIG. 1 shows an overview of a substrate processing system having dechucked wafer detection capability in accordance with a first system embodiment of the present disclosure. [Diagram 2] FIG. 2 shows an example illustrating how a substrate processing system and method for detecting a dechucked wafer works in accordance with a first method embodiment of the present disclosure. [Diagram 3] FIG. 3(a) shows a flow chart of a method for detecting a dechucked wafer in a substrate processing system according to a first method embodiment of the present disclosure, and FIG. 3(b) shows an example with values ​​illustrating how the method according to the first method embodiment of the present disclosure works. [Figure 4] FIG. 4 shows an overview of a substrate processing system having dechucked wafer detection capability in accordance with a second system embodiment of the present disclosure. [Diagram 5] FIG. 5 shows an example illustrating how a substrate processing system and method for detecting a dechucked wafer works in accordance with the second method embodiment of the present disclosure. [Figure 6]FIG. 6 shows a flow chart of a method for detecting a dechucked wafer in a substrate processing system in accordance with a second method embodiment of the present disclosure. [Figure 7] FIG. 7 shows a schematic of a substrate processing system having dechucked wafer detection capability in accordance with a third system embodiment of the present disclosure. [Figure 8] FIG. 8(a) shows an example of a high radio frequency (HRF) power graph generated from an RF generator for multiple cycles generated from the RF generator, and FIG. 8(b) shows an example of a reference voltage (Vref) monitored by the system according to a third method embodiment of the present disclosure, and a maximum value (Vmax) extracted from the reference voltage (Vref), respectively. [Figure 9] FIG. 9 shows a flow chart of a method for detecting a dechucked wafer in a substrate processing system in accordance with a third method embodiment of the present disclosure. [Figure 10] FIG. 10(a) shows an example of obtaining the gradient value b in the (N=4) case, and FIG. 10(b) shows another example of obtaining the gradient value b in the (N=4) case. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Although certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, and obvious modifications and equivalents thereof, and therefore it is not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0020] As used herein, the term "substrate" may refer to any underlying material or materials, including any underlying material or 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. The substrate may be in any form, such as a powder, plate, or workpiece. Substrates in the form of plates include wafers of various shapes and sizes. Substrates may be made of semiconductor materials, such as, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0021] As an example, the substrate in the form of a powder may have applications for pharmaceutical manufacturing. The porous substrate may include a polymer. Examples of workpieces may include medical devices (e.g., stents and syringes), jewelry, tooling, components for battery manufacturing (e.g., anodes, cathodes, or separators), or components for photovoltaic cells.

[0022] The continuous substrate may extend beyond the boundaries of the process chamber in which the deposition process occurs. In some processes, the continuous substrate may be moved through the process chamber such that the process continues until the end of the substrate is reached. The continuous substrate may be fed from a continuous substrate feed system to allow the continuous substrate to be manufactured and output in any suitable form.

[0023] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, webs, flexible materials, bundles of continuous filaments or fibers (e.g., ceramic fibers, or polymeric fibers). Continuous substrates may also include carriers, or sheets, onto which the non-continuous substrates are placed.

[0024] The examples presented in this disclosure are not meant to actually represent any particular materials, structures, or devices, but merely idealized examples used to explain embodiments of the present disclosure.

[0025] The particular examples shown and described are illustrative of the present invention and its best mode, and are in no way intended to limit the scope of aspects and implementations. Also, for simplicity of explanation, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent example functional relationships and / or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in an actual system and / or may not be present in some embodiments.

[0026] It should be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be construed in a limiting sense, as numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, various illustrated operations may be performed in the order illustrated, in other orders, or omitted.

[0027] The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems, and configurations, and other features, functions, operations and / or properties disclosed herein, as well as all equivalents thereof.

[0028] 1 shows a substrate processing system 100 including a reaction chamber 110, a radio frequency (RF) generator 115, a matching unit 114, and a monitor block 120. The reaction chamber 110 may include an upper electrode 111 and a lower electrode 112. The upper electrode 111 may be a showerhead, while the lower electrode 112 may be a susceptor. A wafer 113 may be disposed on the lower electrode 112.

[0029] The RF generator 115 generates the RF power. The matching unit 114 may be configured to adjust the impedance of the reaction chamber 110 so that the generated RF power is more effective in wafer processing, and the lower electrode 112 is grounded to ground 130.

[0030] The substrate processing system 100 may also include a radio frequency (RF) filter 150. The RF filter 150 may be configured with one end connected to the lower electrode 112 and the other end connected to ground 130, as shown in FIG.

[0031] The monitor block 120 may include a phase shift detector 123 and a controller 124 coupled to the phase shift detector 123. The monitor block 120 may be connected in parallel to the reaction chamber 110. Furthermore, the attenuators 121 and 122 may be connected in series to the phase shift detector 123 as shown in FIG.

[0032] The phase shift detector 123 monitors and detects the amount of phase that may be shifted from the signal passing through it. The measured phase shift may be indicated in analog or digital form. The phase shift detector 123 may comprise an oscilloscope. The attenuators 121, 122 may be configured to attenuate or reduce the amplitude of the signal passing through it. Instead of an attenuator, a high voltage probe (not shown) may be used. The attenuator is used to reduce the signal strength so that damage that may be caused to the shift detector 123 by a high power signal may be reduced.

[0033] The controller 124 may be configured to receive parameters such as a first threshold (minimum value), a second threshold (maximum value), and a minimum amount of time (seconds). Figure 2 illustrates one example of a method for using the measured (monitored) phase shift value to determine whether the wafer is dechucked.

[0034] The first and second thresholds (A and B) define the minimum and maximum values ​​(in degrees) respectively such that any phase shift between B and A will be determined to be a normally chucked wafer, while any phase shift greater than the maximum value (A) may be considered a dechucked condition. The minimum time length parameter is the minimum duration of a phase shift used to determine the dechucked condition of a wafer.

[0035] For example, as shown in Figure 2, the first threshold may be 22 degrees and the second threshold may be 25 degrees. The minimum time length may be 3 cycles (here, the parameters are set to the number of cycles for simplicity).

[0036] Controller 124 then measures and monitors the phase shift value picked up from phase shift detector 123. Periods D1-D5 may last for a minimum amount of time, with periods D1 and D2 being examples of an "unchucked wafer", D3 and D4 being examples of a "dechucked wafer", and D5 being an example of a "chucked wafer".

[0037] In D1, there are three phase shift values, such as [25 degrees], [28 degrees], and [30 degrees]. The shift value of the first cycle in D1, i.e., [25 degrees], is equal to the second threshold value, while [28 degrees] and [30 degrees] are greater than the second threshold value. This means that the controller 124 cannot determine that the wafer is in a dechucked state after D1. However, in D2, there are phase shift values, such as [28 degrees], [29 degrees], and [30 degrees], all of which are greater than the second threshold value. After D2, the controller 124 can determine that the wafer is in a dechucked state.

[0038] Although un-chucking and de-chucking events are very different, "de-chucking" may be used throughout this disclosure to mean both un-chucking and de-chucking events.

[0039] D3 has three phase shift values, such as [23 degrees], [27 degrees], and [26 degrees]. [27 degrees] and [26 degrees] are greater than the second threshold, but [23 degrees] is less than the second threshold. Therefore, the controller 124 cannot determine that the wafer is dechucked after D3. However, D4 has phase shift values, such as [28 degrees], [26 degrees], and [30 degrees]. Since all three values ​​are greater than the second threshold, the controller 124 can determine that the wafer is dechucked after D4.

[0040] D5 has three phase shift values, such as [23 degrees], [24 degrees], and [23 degrees], all of which are within the gap between the first and second thresholds, so the controller 124 cannot determine the wafer to be dechucked after D5.

[0041] FIG. 3(a) illustrates a method for determining whether the wafer is dechucked.

[0042] At the beginning of method step 301, controller 124 may be configured to receive parameters such as a first threshold, a second threshold, and a minimum length of time. The role of each parameter may be as described above with reference to FIG. 2. At method step 302, once the parameters are set, controller 124 may be configured to start measuring (or monitoring) the degree of phase shift picked up from phase shift detector 123. At method step 303, for each new input of phase shift value (degrees), controller 124 may be configured to determine whether the measured phase shift value 1) is not within the gap between the first and second thresholds (Condition I), and 2) whether the phase shift value continues for more than a minimum length of time (Condition II).

[0043] FIG. 3(b) shows an example with values ​​that illustrates how the method of FIG. 3(a) works.

[0044] The first threshold is set to [10 degrees] and the second threshold is set to [14 degrees]. The minimum time length is set to [3 cycles]. In cycle 1, a phase shift value [14 degrees] is received, but the time length of cycle 1 is only [1 cycle] (currently only [14 degrees]), so a measurement (step 302) is performed. In cycle 2, a new shift value [16 degrees] is received, but the time length of cycle 2 is [2 cycles] (currently [14 degrees], [16 degrees]), so the measurement (step 302) continues.

[0045] In cycle 3, a new shift value [17 degrees] is received, and condition II is satisfied from cycle 3. Of the three shift values ​​([14 degrees], [16 degrees], [17 degrees]) in the time length of cycle 3, [16 degrees] and [17 degrees] are not within the gap between the first threshold and the second threshold. Thus, in step 302 of the method, the controller 124 may be configured to continue measuring the phase shift values.

[0046] In cycle 4, a new value of [15 degrees] is received and the length of time for cycle 4 has three shift values ​​of [16 degrees], [17 degrees], and [15 degrees]. All values ​​are not within the gap between the first and second thresholds. Therefore, in method step 304, the controller 124 indicates a "DECHUCKED CONDITION."

[0047] Once the wafer is out of its proper position, the dechucked wafer will not typically return to a chucked state. Thus, when the controller 124 indicates "dechucked," it may not be necessary to continue operation. However, in some specific systems having different requirements, the dechucked wafer may return to a chucked state. Thus, in some cases, the method may be configured to continue measurements after the controller 124 indicates "dechucked" in steps 304 and 302.

[0048] Assume that the controller 124 is configured to continue after cycle 4 of FIG. 3(b). In cycle 5, a new value of [14 degrees] is received. [14 degrees] does not satisfy "Condition I", so the controller 124 may be configured to continue the measurement without indicating a "Dechucked State". In cycles 6, 7, and 8, values ​​of [13 degrees], [12 degrees], and [11 degrees] are received, respectively, none of which satisfy "Condition I".

[0049] In cycles 9 and 10, values ​​of [15 degrees] and [17 degrees] are received in sequence. Since [11 degrees] is included in the length of time of cycles 9 and 10, the controller 124 may be configured to measure the phase shift value and not indicate a "dechucked condition" until cycle 10.

[0050] New values ​​of [21 degrees] and [20 degrees] are received for cycles 11 and 12. Because the phase shift values ​​for the time length of cycle 11 ([15 degrees], [17 degrees], [21 degrees]) and the time length of cycle 12 ([17 degrees], [21 degrees], [20 degrees]) satisfy "Condition I," the controller 124 may be configured to indicate a "DECHUCK CONDITION" after cycles 11 and 12. Thus, as shown in FIG. 3(b), with parameters of first threshold [10 degrees], second threshold [14 degrees], and minimum time length [3 cycles], the controller 124 may be configured to indicate a "DECHUCK CONDITION" only after cycles 4, 11, and 12.

[0051] 4 shows a second embodiment of the present disclosure. The substrate processing system 400 includes a reaction chamber 410, a radio frequency (RF) generator 415, a matching unit 414, and a monitor block 420. The reaction chamber 410 may include an upper electrode 411 and a lower electrode 412. The upper electrode 411 may be a showerhead, and the lower electrode 412 may be a susceptor. A wafer 413 may be disposed on the lower electrode 412. The substrate processing system 400 may also include an RF filter 450 connected at one end to the lower electrode 412 and at the other end to ground 430, as shown in FIG. 4.

[0052] The RF generator 415 may be configured to generate RF power. The matching unit 414 may be configured to adjust the impedance of the reaction chamber 410 so that the generated RF power is more effective in wafer processing, and the lower electrode 412 is grounded to ground 430.

[0053] The monitor block 420 may include a network analysis unit 423 and a controller 424 coupled to the network analysis unit 123. The monitor block 420 may be connected in parallel to the reaction chamber 410. Also, low pass filters (LPFs) 421 and 422 may be connected in series to the network analysis unit 423 as shown in FIG.

[0054] The network analysis unit 423 may be configured to monitor and measure both the amplitude and phase characteristics of the signal using scattering parameter (S-parameter) theory. Since explaining the S-parameter theory would be outside the scope of this disclosure, only the results of the theory (i.e., the formula for obtaining the transmission coefficient) are used. The formula for obtaining the transmission coefficient of forward transmission is S 21 =S transmitted / S incident [Formula 1](S 21 : Transmission coefficient, S transmitted: The signal input to the device under test, S incident : signal emitted by the device under test).

[0055] The network analysis unit 423 may be a vector network analyzer. The LPFs 421, 422 may be configured to attenuate high frequency signals while allowing low frequency signals to pass.

[0056] The controller 424 may be configured to receive parameters such as threshold values. Figure 5 shows an example of how the measured (monitored) transmission coefficients are used to determine whether the wafer is in a dechucked state.

[0057] Curve 501 may be the transmission coefficient from Equation 1 when the wafer 413 is normally chucked, and curve 502 may be the transmission coefficient when the wafer 413 is dechucked. As can be seen in Figure 5, the y-axis is magnitude, the x-axis is frequency, and the slope of curve 502 is greater than the slope of curve 501.

[0058] The curve 503 may be a received parameter (threshold value). A curve of a transmission coefficient having a slope greater than the slope of the threshold curve 503 may be determined to represent a dechucked wafer, and a curve of a transmission coefficient having a slope less than the slope of the threshold curve 503 may be determined to represent a chucked wafer.

[0059] Since the LPFs 421, 422 attenuate signals with frequencies above 1 MHz, the frequency range in Figure 5 can be 1 Hz to 1 MHz. This frequency spectrum can vary from system to system for better dechucking detection.

[0060] FIG. 6 illustrates a second method embodiment of a method for determining whether a wafer is in a dechucked state.

[0061] Initially, in method step 601, the controller 424 may be configured to receive parameters such as threshold curve values. In method step 602, once the parameters are set, the controller 124 may be configured to start measuring (or monitoring) transmission coefficients picked up from the network analysis unit 423. The network analysis unit 423 may be configured to use the following [Equation 2] to obtain the transmission coefficients. As is evident from the equation, Equation 2 is derived from Equation 1.

[0062] Transmission coefficient = S out / S in , (S out : the signal output from the first LPF 421, S in : signal input to the second LPF 422) [Equation 2]

[0063] After obtaining the transmission coefficient, in method step 603, the controller 424 may be configured to determine whether it is true that the measured transmission coefficient is greater than a threshold value, meaning whether the slope of the newly measured transmission coefficient curve is greater than the slope of the threshold curve.

[0064] If the measured transmission coefficient is greater than the threshold, then the controller 424 may be configured to indicate a "dechuck condition" in method step 604. If the measured transmission coefficient is equal to or less than the threshold, then the controller 424 may be configured to continue measuring the transmission coefficient without indicating a "dechuck condition" in method step 602.

[0065] Once the wafer is out of its proper position, the dechucked wafer will not typically return to the "chuck" state. Thus, when the controller 424 indicates a "dechucked state", it may not be necessary to continue. However, in some particular systems having different requirements, the dechucked wafer may return to a chucked state. Thus, similar to method steps 604 and 602, in some cases the controller 424 may be configured to continue the measurement after indicating a "dechucked state".

[0066] 7 shows a third embodiment of the present disclosure. The substrate processing system 700 includes a reaction chamber 710, a radio frequency (RF) generator 715, 714, and a screen circuit 721 connected to the matching unit 714. The reaction chamber 710 may include an upper electrode 711 and a lower electrode 712. The upper electrode 711 may be a showerhead, and the lower electrode 712 may be a susceptor. A wafer 713 may be placed on the lower electrode 412.

[0067] The RF generator 715 generates RF power. The matching unit 714 may be configured to adjust the impedance of the reaction chamber 110 for the generated RF power to be more effective in wafer processing, and the lower electrode 712 is grounded to ground 730.

[0068] The screening circuit 721 may include one or more resistors, one or more capacitors, one or more inductors, and one or more diodes, and the screening circuit 721 is connected to a reference voltage (V refA controller 722 may be connected to the screen circuit 721 and may be configured to measure and monitor the reference voltage and calculate a tilt value to determine if the wafer 713 is in a dechucked state.

[0069] FIG. 8(a) shows an example of a high radio frequency (HRF) power graph for multiple cycles generated from an RF generator, and FIG. 8(b) shows a graph of a reference voltage monitored by the controller 722 and a maximum value extracted from the reference voltage (V max ) is shown below.

[0070] Concurrent with the HRF power cycle 810 appears a reference voltage 820. However, in the screening circuit 721, the crest of the voltage 821 may not be as flat as the crest of the HRF power 811. From this non-flat crest 821, a maximum value 822 may be derived.

[0071] FIG. 9 illustrates a third method embodiment of the present disclosure.

[0072] In steps 910 and 911 of the method, the controller 722 may be configured to receive parameters such as a predetermined number N and a threshold value for slope determination, and the controller 722 also generates N reference voltages (V ref,1 , V ref,2 , V ref,3 , … V ref,N-1 , V ref,N ) may be configured to measure

[0073] After measuring the N reference voltages, in method step 912, the controller 722 calculates the maximum value of each of the reference voltages (V max,1 , V max,2 , V max,3 , ..., V max,N-1 , V max,N Next, in step 913 of the method, the controller 722 may be configured to extract y nThe method may be configured to calculate:

[0074]

number

[0075] Next, in method step 914, the controller 722 may be configured to derive the slope value b using the following equation [Equation 4]:

[0076]

number

[0077] Next, in method step 915, the controller 722 may be configured to determine whether it is true that the tilt value b is below a threshold value, and if so, in method step 916, the controller 722 may be configured to indicate a "dechuck condition." If not, the controller 722 may be configured to continue measuring the reference voltage.

[0078] FIG. 10(a) shows an example of obtaining the gradient value b when (N=4).

[0079] Shown is y n and the slope value b, which is assumed to be V for simplicity. ref V from the graph max The process of obtaining the value is omitted.

[0080] In step 913 of the method, for each y n (1≦n≦4) The value is derived using Equation 3 as follows:

[0081] y1=(V max,1 ) / 1=[10 / 1]=10,

[0082] y2=(V max,1 +V max,2) / 2=[(10+9) / 2]=9.5,

[0083] y3=(V max,1 +V max,2 +V max,3 ) / 3=[(10+9+10) / 3]=9.667,

[0084] y4=(V max,1 +V max,2 +V max,3 +V max,4 ) / 4=[(10+9+10+10) / 4]=9.75,

[0085] Then, in method step 914, b is derived using Equation 4 below as follows:

[0086]

number

[0087] Therefore, the value is V max [10, 9, 10, 10], where N=4, the slope value b is −0.058.

[0088] Another example with N=4 is shown in FIG. 10(b).

[0089] V max For values ​​[10, 9, 8, 7], the slope value b is derived as follows:

[0090] In step 913 of the method, for each y n (1≦n≦4) The value is derived using Equation 3 as follows:

[0091] y1=(V max,1 ) / 1=[10 / 1]=10,

[0092] y2=(V max,1 +V max,2 ) / 2=[(10+9) / 2]=9.5,

[0093] y3=(V max,1 +Vmax,2 +V max,3 ) / 3=[(10+9+8) / 3]=9,

[0094] y4=(V max,1 +V max,2 +V max,3 +V max,4 ) / 4=[(10+9+8+7) / 4]=8.5,

[0095] Then, in method step 914, b is derived using Equation 4 as follows:

[0096]

number

[0097] The value is V max [10, 9, 8, 7], and when N=4, the slope value b is −0.5.

[0098] If the wafer is well chucked, the tilt value b will be zero (0) or very close to zero (0). The decision threshold may vary based on the specifics of the system and requirements.

[0099] If the threshold value may be set to "-0.1", then the slope value in Figure 10(a) (-0.05833) is greater than the threshold value, while the slope value in Figure 10(b) (-0.5) is less than the threshold value. Thus, in method step 915, controller 722 may be configured to determine whether b is less than the threshold value.

[0100] In the case of Figure 10(b), in method step 916, the controller 722 may be configured to indicate a "dechucking condition." However, in Figure 10(a), in method step 911, the controller 722 may be configured to measure a reference voltage.

[0101] The above-described system and method configurations are merely illustrative of the application of the principles of the present invention and numerous other embodiments and modifications can be made without departing from the spirit and scope of the invention as defined in the appended claims. The scope of the invention should therefore be determined not with reference to the above description but should instead be determined with reference to the appended claims, along with their full scope of equivalents.

Claims

1. 1. A substrate processing system having the capability to detect whether a wafer is dechucked during processing, comprising: a reaction chamber configured to process a wafer, the reaction chamber comprising an upper electrode and a lower electrode; a radio frequency (RF) generator configured to generate radio frequency power within the reaction chamber; a matching unit disposed between the reaction chamber and the RF generator, configured to adjust the impedance of the reaction chamber so that the generated radio frequency power is more effective in the process; a phase shift detector connected in parallel to the reaction chamber and configured to detect a phase shift between a signal input to the upper electrode and a signal output from the lower electrode; a controller coupled to the phase shift detector and configured to receive parameters to determine and indicate a chuck status of the wafer.

2. a first attenuator disposed between the upper electrode and the phase shift detector; The substrate processing system of claim 1 , further comprising a second attenuator disposed between the phase shift detector and the bottom electrode.

3. A method for detecting whether a wafer is in a dechucked state in a substrate processing system according to any one of claims 1 to 2, comprising the steps of: receiving a first threshold, a second threshold, and a minimum amount of time; measuring a phase shift from the upper electrode and the lower electrode; determining whether it is true that the measured phase shift is not within the first and second thresholds and continues for the minimum length of time; indicating a dechucking condition if determined to be true and repeating the measuring step if determined to be false.

4. 1. A substrate processing system having the capability to detect whether a wafer is dechucked during processing, comprising: a reaction chamber configured to process the wafer, the reaction chamber comprising an upper electrode and a lower electrode; a radio frequency (RF) generator configured to generate a radio frequency signal for processing the wafer in the reaction chamber; a matching unit disposed between the reaction chamber and the RF generator, configured to adjust the impedance of the reaction chamber so that the generated radio frequency power is more effective in the process; a network analysis unit connected in parallel to the reaction chamber and configured to detect a transmission coefficient of the reaction chamber; a controller coupled to the network analysis unit and configured to receive parameters to determine and indicate a dechucking status of the wafer.

5. a first low pass filter (LPF) disposed between the upper electrode and the network analysis unit; The substrate processing system of claim 4 , further comprising: a second LPF disposed between the network analysis unit and the lower electrode.

6. The substrate processing system according to any one of claims 4 to 5, wherein the network analysis unit is a vector network analyzer.

7. The transmission coefficient is expressed by the following formula: S ２１ = S ｏｕｔ / S ｉｎ , (S ２１ : transmission coefficient, S ｏｕｔ : the signal output from the first LPF, S ｉｎ The substrate processing system according to any one of claims 4 to 5, wherein the signal is calculated by:

8. A method for detecting whether a wafer is in a dechucked state in a substrate processing system according to any one of claims 4 to 5, comprising the steps of: Receiving a threshold value; measuring a transmission coefficient from the reaction chamber; determining whether it is true that the measured transmission coefficient is greater than the threshold; indicating a dechucking condition if determined to be true and repeating the measuring step if determined to be false.

9. The transmission coefficient is expressed by the following formula: S ２１ = S ｏｕｔ / S ｉｎ , (S ２１ : transmission coefficient, S ｏｕｔ : a signal output from the first LPF, S ｉｎ 9. The method of claim 8, wherein the second LPF is calculated by:

10. 1. A substrate processing system having the capability to detect whether a wafer is dechucked during processing, comprising: a reaction chamber configured to process the wafer; a radio frequency (RF) generator configured to generate radio frequency power for processing the wafer in the reaction chamber; a matching unit disposed between the reaction chamber and the RF generator, configured to adjust the impedance of the reaction chamber so that the generated radio frequency power is more effective in the process; a screen circuit connected in series to the alignment unit and configured to generate a reference voltage used to calculate a tilt value (b) to determine whether the wafer is in a dechucked state; a controller coupled to the screen circuit and configured to monitor the reference voltage, calculate the tilt value, and determine whether the wafer is in a dechucked state.

11. The substrate processing system of claim 10 , wherein the screening circuit comprises two or more resistors, two or more capacitors, one or more coils, and one or more diodes.

12. 11. A method for detecting whether a wafer is dechucked in a substrate processing system as recited in claim 10, comprising the steps of: receiving a predetermined number (N) and a threshold; Measuring N reference voltages (Vref,i) from said screening circuit (1≦i≦N); extracting a maximum value (Vmax,i) of each of the N reference voltages (Vref,i) (1≦i≦N); Using Equation 1, the moving average value y ｎ (1≦n≦N) (Formula 1: [0010] (1≦n≦N) Formula 2 (Formula 2: [0025] deriving a slope value b using determining whether it is true that the slope value b is less than the threshold value; indicating a dechucking condition if determined to be true and repeating the measuring step if determined to be false.

Images