Adsorption process and system for substrate processing chamber

Abstract

The present disclosure relates to methods and systems for adsorption in a substrate processing chamber. In one embodiment, a method for adsorbing one or more substrates in a substrate processing chamber includes: applying an adsorption voltage to a susceptor. The substrate is disposed on a support surface of the susceptor. The method also includes: ramping the adsorption voltage from the applied voltage; detecting an impedance shift when ramping the adsorption voltage; determining a corresponding adsorption voltage when the impedance shift occurs; and determining a precise adsorption voltage based on the impedance shift and the corresponding adsorption voltage.

Description

Background Art Technical Field

[0002] Aspects of the present disclosure are generally directed to methods and systems for operating a substrate processing chamber, including methods of sucking substrates.

[0003] Related technical notes

[0004] During processing of a substrate, the substrate is sometimes sucked to a pedestal within a substrate processing chamber. For example, when a substrate is bent, the substrate may be sucked to the pedestal during processing. However, due to variations in pedestal characteristics and / or variations in substrate characteristics, it is difficult, expensive, and time consuming to determine the suction voltage that should be applied to the pedestal during processing. If the applied suction voltage is too low, arcing may occur during substrate processing. If the applied suction voltage is too high, the substrate may also suffer backside damage, resulting in defects and reduced yield of the substrate processing operation.

[0005] Therefore, there is a need for an improved method of attaching substrates that reduces or eliminates backside damage and arcing and improves yield in a cost-effective manner. Summary of the invention

[0006] Embodiments of the present disclosure are generally directed to methods and systems for operating a substrate processing chamber, including methods of adsorbing a substrate.

[0007] In one embodiment, a method of clamping one or more substrates in a substrate processing chamber includes: applying a clamping voltage to a susceptor. Disposing the substrate on a support surface of the susceptor. The method further includes: ramping the clamping voltage from the applied voltage; detecting an impedance shift while ramping the clamping voltage; and determining a corresponding clamping voltage when the impedance shift occurs. The method further includes: determining a precise clamping voltage based on the impedance shift and the corresponding clamping voltage.

[0008] In one embodiment, a method for clamping one or more substrates in a substrate processing chamber includes: applying a clamping voltage to a susceptor using a preselected value. The substrate is disposed on a support surface of the susceptor. The method further includes: detecting an impedance shift; determining a precise clamping voltage based on the impedance shift; and adjusting the applied clamping voltage using the precise clamping voltage.

[0009] In one embodiment, a controller for a substrate processing chamber system includes a processor. The controller includes a set of computer instructions that, when executed, instruct the processor to cause a direct current voltage generator to apply a clamping voltage to a pedestal. The set of computer instructions, when executed, cause an impedance detector to detect an impedance shift of a radio frequency energy generator and determine a precise clamping voltage based on the impedance shift. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order that the manner in which the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure briefly summarized above may be obtained by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only common embodiments of the present disclosure and are therefore not to be considered limiting of its scope, as the present disclosure may admit to other equally effective embodiments.

[0011] Figure 1 is a partial schematic cross-sectional view of a substrate processing chamber system according to one embodiment.

[0012] Figure 2 is a schematic illustration of a method of adsorbing a substrate in a substrate processing chamber according to one embodiment.

[0013] Figure 3 is an illustration of an image showing impedance shift according to one embodiment.

[0014] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. DETAILED DESCRIPTION

[0015] The present disclosure relates to methods and systems for sucking substrates in a substrate processing chamber. Figure 1 A partial schematic cross-sectional view of a substrate processing chamber system 101 according to one embodiment is shown. The substrate processing chamber system 101 includes a chamber 100 having a susceptor 138 disposed therein. The chamber 100 may be, for example, a chemical vapor deposition (CVD) chamber, a plasma enhanced CVD (PECVD) chamber, or a physical vapor deposition (PVD) chamber. The chamber 100 has a chamber body 102 and a chamber lid 104. The chamber body 102 includes an interior volume 106 and a pumping path 108 therein. The interior volume 106 is a space defined by the chamber body 102 and the chamber lid 104. The pumping path 108 is a path formed in the chamber body 102 that is coupled to the pumping volume 112 formed in the pumping plate 114. The pumping path 108 facilitates the removal of gas from the interior volume 106.

[0016] The chamber 100 includes a gas distribution assembly 116 coupled to and / or disposed in the chamber lid 104 to deliver a flow of one or more gases into the processing region 110. The processing region 110 includes a portion of the interior volume 106 located between the substrate support 138 and the chamber lid 104. The gases delivered by the gas distribution assembly 116 may include, for example, one or more process gases (such as one or more inert gases and / or one or more precursor gases). In one example, the one or more process gases include a precursor gas that includes tetraethyl orthosilicate (TEOS) to form a film on the substrate 136. The gas distribution assembly 116 includes a gas manifold 118 coupled to a gas inlet channel 120 formed in the chamber lid 104. The gas manifold 118 receives a flow of gas from one or more gas sources 122 (two are shown). The gas flow received from one or more gas sources 122 is distributed across the gas box 124, flows through the plurality of openings of the backing plate 126, and is further distributed across the plenum 128 defined by the backing plate 126 and the face plate 130. The gas flow then flows into the processing region 110 of the interior volume 106 through the plurality of openings 132 of the face plate 130. A pump 133 is connected to the pumping path 108 through a conduit 134 to control the pressure within the processing region 110 and exhaust gases and byproducts from the processing region 110 through the pumping volume 112 and the pumping path 108.

[0017] The interior volume 106 includes a pedestal 138 that supports a substrate 136 within the chamber 100 on a support surface 138a of the pedestal 138. The pedestal 138 includes an electrode 140 disposed within the pedestal 138. The electrode 140 may include a conductive mesh, such as a conductive mesh containing tungsten, copper, or molybdenum. The electrode 140 may include any material for heating, including an alternating current (AC) coil. The electrode 140 is coupled to a power source 159, such as a direct current (DC) voltage generator. The electrode 140 is configured to supply an adsorption voltage received from the DC voltage generator 159 to the pedestal 138. The adsorption voltage applies an adsorption force to the substrate 136, so that the substrate 136 is adsorbed to the support surface 138a of the pedestal 138. The electrostatic force applied to the substrate 136 causes the substrate to be pulled down toward the electrode 140 to facilitate adsorption of the substrate 136 to the support surface 138a. The adsorption force acting on the substrate 136 facilitates eliminating the bow of the substrate 136 or flattening the substrate 136 .

[0018] The electrode 140 is coupled to a radio frequency (RF) energy generator 156. The electrode 140 is configured to propagate RF energy received from the RF energy generator 156 through the pedestal 138 and into the processing region 110. For example, when one or more process gases are present in the processing region 110, the electrode 140 can propagate RF energy such that a plasma 141 is generated in the processing region 110.

[0019] The electrode 140 is coupled to a heating power source 180 that supplies heating power to the electrode 140. The heating power may be, for example, alternating current (AC). The electrode 140 is configured to heat the susceptor 138 using the heating power received from the heating power source 180.

[0020] The electrode 140 is coupled to the RF energy generator 156, the heating power supply 180, and the DC voltage generator 159 through the conductive rod 160 and the matching circuit 158. The impedance detector 190 is coupled to the RF energy generator 156. The impedance detector 190 is configured to detect an impedance shift of the RF energy generator 156 when the DC voltage generator 159 applies a clamping voltage to the pedestal 138 through the electrode 140. In one embodiment, which may be combined with other embodiments, the impedance detector 190 is additionally or alternatively coupled to other components of the substrate processing chamber system 101. For example, the impedance detector 190 may be coupled to and configured to detect an impedance shift in one or more of the substrate 136, the pedestal 138, the electrode 140, the heating power supply 180, the DC voltage generator 159, the chamber body 102, the chamber lid 104, the support surface 138a, the face plate 130, the backing plate 126, and / or the second RF energy generator 166. The present disclosure contemplates that the impedance detector 190 may be configured to detect impedance shifts of any component of the substrate processing chamber system 101 and use such information in accordance with various aspects disclosed herein.

[0021] The pedestal 138 is movably disposed in the interior volume 106 by rods 142 coupled to a lift system. Movement of the pedestal 138 facilitates transfer of the substrate 136 to and from the interior volume 106 through a slit valve formed through the chamber body 102. The pedestal 138 can also be moved to different processing positions for processing the substrate 136. The pedestal 138 can also have an opening disposed therethrough through which a plurality of lift pins 150 can be movably disposed. In a lowered position, the plurality of lift pins 150 protrude from the pedestal 138 by contacting a lift plate 152 coupled to a bottom 154 of the chamber body. The protrusion of the lift pins 150 places the substrate 136 in a spaced relationship from the pedestal 138 to facilitate transfer of the substrate 136.

[0022] During substrate processing, the electrode 140 heats the susceptor 138 as gases flow into the processing region 110. Also during substrate processing, the electrode 140 transmits radio frequency (RF) energy, alternating current (AC), or direct current (DC) to promote plasma generation in the processing region 110 and / or to promote the attraction of the substrate 136 to the susceptor 138. The heat, gases, and energy from the electrode 140 promote the deposition of films onto the substrate 136 during substrate processing.

[0023] The generation of plasma 141 is facilitated via the face plate 130 and the electrode 140 coupled to the chamber body 102 and grounded. For example, the RF energy generator 156 provides RF energy to the electrode 140 within the pedestal 138 to facilitate the generation of plasma 141 between the pedestal 138 and the face plate 130 of the gas distribution assembly 116. The RF energy generator 156 is connected to the ground 171. The second RF energy generator 166 is also configured to provide RF energy to the chamber 100. The second RF energy generator 166 is connected to the ground 173. Although the second RF energy generator 166 is shown, it is contemplated by the present disclosure that other power sources may be used in place of or in combination with the second RF energy generator 166. For example, a second alternating current (AC) power source or a second direct current (DC) power source may be used. It is contemplated by the present disclosure that the second AC power source and / or the second DC power source may be coupled to the impedance detector 190.

[0024] The substrate processing chamber system 101 includes a controller 192 configured to control one or more of the components of the substrate processing chamber system 101. The controller 192 includes a central processing unit (CPU) 193, a support circuit system 194, and a memory 195 containing associated control software 196. The CPU 193 may include a processor. The control software 196 includes a set of computer instructions that, when executed, instruct the CPU 193 of the controller 192 to perform one or more operations using one or more components of the substrate processing chamber system 101. The controller 192 may include any form of general-purpose computer processor that can be used in an industrial environment to control various chambers and sub-processors. The CPU 193 may use any suitable memory 195, such as random access memory, read-only memory, a floppy disk drive, an optical disk drive, a hard disk, or any other form of digital storage, local or remote. Various support circuits may be coupled to the CPU 193 for supporting the chamber 100. The controller 192 may be coupled to another controller located near the individual chamber components. Bidirectional communication between the controller 192 and various other components of the chamber 100 is handled by a number of signal lines collectively referred to as signal buses, some of which are Figure 1 shown.

[0025] Figure 1 The controller 192 shown is configured to control at least one or more of the gas source 122, the pump 133, the RF energy generator 156, the DC voltage generator 159, the second RF energy generator 166, the heating power supply 180, and the impedance detector 190. In one embodiment that can be combined with other embodiments, the controller 192 is configured to, when executed by a processor (such as a CPU 193), enable Figure 2One or more of the operations shown in the method 200 are performed. In one example, the control software 196 includes a set of computer instructions that, when executed, instruct the CPU 193 of the controller 192 to Figure 2 One or more operations shown in method 200 are performed.

[0026] Figure 2 is a schematic illustration of a method 200 for adsorbing a substrate in a substrate processing chamber. At operation 201, an adsorption voltage is applied to a pedestal having a substrate disposed on a support surface of the pedestal, and / or radio frequency (RF) energy is supplied to the substrate processing chamber. In one embodiment that may be combined with other embodiments, the adsorption voltage is applied using a preselected value for the adsorption voltage. The preselected value may be obtained based on, for example, the specifications of the processing chamber, substrate, pedestal, or electrode, or the material thereof. The preselected value may be obtained from a previous substrate processing or adsorption operation. In one example, when a new pedestal, chamber, and / or substrate is used in a substrate processing operation, the preselected value is obtained using one or more experimental runs.

[0027] In optional operation 203, a plasma such as an inert plasma is generated. At optional operation 205, the adsorption voltage is ramped up or ramped down until an impedance shift occurs. Alternatively, the adsorption voltage can be ramped up from the applied voltage to a second larger voltage to identify a voltage between the applied voltage and the second larger voltage when the impedance shift occurs. In one embodiment that can be combined with other embodiments, the second larger voltage is a preselected value. At operation 207, the impedance shift is detected. The impedance shift indicates that the substrate is adsorbed to the support surface of the pedestal.

[0028] In one embodiment, which may be combined with other embodiments, the clamping voltage is ramped up or down in one or more voltage increments until an impedance shift occurs. In one example, the clamping voltage is ramped up in 50 volt increments, each increment being applied for 5 seconds or more (such as 10 seconds or more) to allow the impedance sensor to stabilize until an impedance shift occurs. In one example, the clamping voltage is ramped down in 100 volt increments, each increment being applied for 5 seconds or more (such as 10 seconds or more) until an impedance shift occurs.

[0029] The impedance shift is a shift in impedance of at least a predetermined amount, such as 0.5 ohms or more. In one embodiment, which may be combined with other embodiments, after applying the adsorption voltage at block 201 for a predetermined period of time, such as 5 seconds or more (such as 10 seconds or more), a first impedance value is measured. In such an embodiment, after ramping the adsorption voltage at block 205 and applying the ramped adsorption voltage for another equal or different period of time, such as about 5 seconds or more (such as 10 seconds or more), a second impedance value is measured. Applying the adsorption voltage for a predetermined period of time allows the impedance value to stabilize for accurate measurement. The difference between the first impedance value and the second impedance value indicates an impedance shift. When the increment between the measured impedance values ​​exceeds a predetermined threshold amount, a shift is considered to have occurred. In one example, a shift of 0.5 ohms or more indicates that the substrate is adsorbed and / or that the bending of the substrate is reduced or eliminated. However, it is noted that other shift values ​​are contemplated.

[0030] In one embodiment that may be combined with other embodiments, an impedance shift is used to verify that the substrate is adsorbed and / or that the bending of the substrate is reduced or eliminated. In such an embodiment, the value of the impedance shift at box 207 is less than a target value (such as 0.1 ohms or less) is used to verify that the substrate is adsorbed to the base. In one example, after measuring the impedance shift at box 207, a second impedance shift is measured. If the second impedance shift is equal to or less than the target value (such as 0.1 ohms or less), it is verified that the substrate is adsorbed to the base. If the second impedance shift is greater than a predetermined target value for confirming adsorption, the substrate may have become at least partially de-adsorbed from the base.

[0031] Without being bound by theory, it is believed that the impedance shift is caused by a change in charge flow between the substrate and other component(s) of the substrate processing chamber system. For example, adsorbing the substrate may remove the curvature of the substrate, flattening the substrate toward the support surface of the pedestal, thereby reducing one or more gaps between the substrate and the support surface. Reducing the one or more gaps between the substrate and the support surface causes a change in charge flow between the substrate and other component(s), such as the pedestal. The change in charge flow causes an impedance shift in one or more components of the substrate processing chamber system.

[0032] In one embodiment that may be combined with other embodiments, the operation of detecting the impedance shift includes measuring the impedance shift. A device such as an impedance detector (e.g., the impedance detector 190 described above) may be used to detect and / or measure the impedance shift. In one embodiment that may be combined with other embodiments, the impedance shift is an impedance shift of a radio frequency (RF) energy generator that supplies radio frequency energy to a substrate processing chamber. The present disclosure contemplates that the impedance shift may be detected and / or measured for any component of the substrate processing chamber. At operation 209, the impedance shift is used to determine a precise adsorption voltage. In one embodiment that may be combined with other embodiments, the precise adsorption voltage is a minimum voltage value that adsorbs the substrate to the support surface of the susceptor without any bending, for example. In one example, the precise adsorption voltage is the adsorption voltage applied at the moment when the impedance shift occurs. Determining and using the precise adsorption voltage facilitates increasing the likelihood that the substrate will be adsorbed to the support surface of the susceptor in operations involving substrates, chambers, or susceptors with varying characteristics. Adsorbing the substrate facilitates reducing or eliminating the bending of the substrate, and facilitates reducing the likelihood of arcing by removing or alleviating the gap between the substrate support surface and the back side of the substrate. Reducing the likelihood of arcing promotes reducing substrate defects and improving the yield of substrate processing operations. Using precise clamping voltages also allows the operator to choose not to use high clamping voltages during substrate processing, which can cause substrate backside damage. Reducing the likelihood of backside damage reduces the likelihood of substrate defects and improves the yield of substrate processing operations.

[0033] In one example, the precise clamping voltage may be based on the clamping voltage at the moment of the impedance excursion, plus an additional voltage amount to ensure clamping. For example, the precise clamping voltage may be equal to the clamping voltage at the moment of the impedance excursion, plus 5%, 10%, 15%, 20%, 25%, etc. In such an example, the precise clamping voltage may be determined for a first substrate or a first batch of substrates, and then applied to multiple processing runs. The inclusion of the additional voltage amount increases the likelihood that the precise clamping voltage will promote clamping and increases the benefits of many processed substrates as described herein without having to perform the method 200 for each individual substrate during processing. It is also contemplated that the method 200 may be performed for each substrate during processing so that the precise clamping voltage is the optimal clamping voltage for each individual substrate.

[0034] In an optional embodiment that may be combined with other embodiments, the precise clamping voltage is determined by generating a first image of a first impedance trace (e.g., a plot of impedance values ​​versus time for one or more applied voltages), the first impedance trace measured when the applied clamping voltage and / or the ramped clamping voltage is applied to the substrate for a predetermined period of time (such as 5 seconds or more). The first image of the first impedance trace is compared with a second image of a second impedance trace, the second impedance trace being measured for the same voltage applied to a different substrate for the same period of time. In one example, the different substrate is a flat silicon substrate that does not include a bend. If the first impedance trace matches the second impedance trace, the applied voltage for the first impedance trace is determined to be the precise clamping voltage. If the first impedance trace does not match the second impedance trace, the applied voltage is ramped until the first impedance trace matches the second impedance trace. In one example, as discussed above, when the predetermined amount is used to determine the precise clamping voltage, the first impedance trace that matches the second impedance trace is used to confirm the appropriate voltage value for the precise clamping voltage.

[0035] By using the impedance shift to determine the precise clamping voltage, the precise clamping voltage can be determined in real time during substrate processing operations. The substrate processing operation does not need to wait until the deposition process on the substrate is completed in order to inspect the substrate to determine whether the applied clamping voltage is sufficient. This facilitates saving time and cost in substrate processing operations and facilitates improving yield.

[0036] At optional operation 211, the applied adsorption voltage is adjusted to the precise adsorption voltage. Adjusting the applied adsorption voltage to the precise adsorption voltage for subsequent processing can achieve the benefits described herein regarding the precise adsorption voltage in a timely and cost-effective manner. The precise adsorption voltage also allows the substrate processing operation to efficiently take into account and adapt to the varying characteristics between different substrates. For example, if a new susceptor is used in a substrate processing operation, the susceptor may have a different thermal conductivity compared to the previously used susceptor. Using the precise adsorption voltage to adjust the applied adsorption voltage allows the substrate processing operation to efficiently adapt to the different properties of the new susceptor compared to the previous susceptor. This can be done each time a new susceptor is used. As another example, the precise adsorption voltage can be used to adjust a preselected value obtained from a specification for a new susceptor. In one aspect, one or more operations of method 200 are performed each time a new susceptor is used in a substrate processing operation.

[0037] As another example, if a new substrate is used in a substrate processing chamber, the new substrate may have different bow characteristics than previously processed substrates. The different bow characteristics may be associated with different clamping voltages that will eliminate the bow in the substrate. Using the various aspects discussed herein, a clamping voltage may be applied to the substrate that eliminates or mitigates the bow without being excessive, thereby reducing the likelihood of backside damage.

[0038] At optional operation 213, the precise adsorption voltage is stored. In one embodiment that may be combined with other embodiments, the precise adsorption voltage is stored in a memory for use in subsequent substrate processing operations. At optional operation 215, the precise adsorption voltage is applied. At optional operation 217, in response to applying the precise adsorption voltage, one or more substrates are adsorbed to the support surface of the pedestal. The one or more substrates of optional operation 217 may include the substrate used in operation 201. The one or more substrates of optional operation 217 may be different from the substrate used in operation 201. The one or more substrates of optional operation 217 may include a second substrate and / or a third substrate different from the substrate used in operation 201.

[0039] At optional operation 219, in response to applying the precision clamping voltage, bending of the one or more substrates is reduced or eliminated. The one or more substrates of optional operation 219 may include the substrate used in operation 201. The one or more substrates of optional operation 219 may be different from the substrate used in operation 201. The one or more substrates of optional operation 219 may include a second substrate and / or a third substrate different from the substrate used in operation 201.

[0040] At optional operation 221, a deposition process is performed while applying a precise clamping voltage. For example, a film may be deposited onto one or more substrates using one or more process gases and a generated process plasma that deposits the film onto the one or more substrates.

[0041] At optional operation 223, one or more of operations 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, and / or 221 are repeated for one or more additional substrates. The one or more additional substrates of optional operation 223 may include a second substrate and / or a third substrate different from the substrate used in operation 201.

[0042] Method 200 is not limited to Figure 2 The order or number of operations shown may include other implementations that include reordering, repeating, adding and / or removing one or more of operations 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221 and / or 223.

[0043] Figure 3is an illustration of an image 300 showing an impedance shift according to one embodiment. The image 300 shows an impedance shift that occurs after a clamping voltage is ramped up. In the illustrated embodiment, a first clamping voltage (e.g., 550 volts) is applied to a substrate for a predetermined time period, such as 20 seconds. While the first clamping voltage is applied, a first impedance trace 301 is generated by measuring the impedance over the entire 20 seconds. After the predetermined time period has elapsed, a first impedance value 302 is measured. The clamping voltage is ramped up in predetermined voltage increments (e.g., 50 volts or about 10%) to apply a second clamping voltage (e.g., 600 volts) to the same substrate for an additional time period. In one example, the additional time period is the same as the first time period, such as 20 seconds. While the second clamping voltage is applied, a second impedance trace 303 is generated by measuring the impedance over the entire additional 20 seconds. After the second time period (e.g., 20 seconds) has elapsed, a second impedance value 304 is measured. As shown, the impedance of the second impedance trace 303 is substantially stable after the additional 20 seconds have elapsed. This process is repeated, comparing the stable impedance to the previously stable impedance, until an impedance excursion of at least a threshold is determined.

[0044] The difference 305 between the second impedance value 304 of at least the threshold value (e.g., 0.5 ohms) and the first impedance value 302 indicates that the bending of the substrate is reduced or eliminated. The impedance shift indicates that the second adsorption voltage corresponds to the adsorption voltage when adsorption of the substrate to the support surface occurs. Therefore, there is no need to excessively apply power for adsorption.

[0045] It is noted that image 300 is only an example and other images may be generated or detected. Benefits of the present disclosure include reduced arcing, improved substrate suction to a susceptor support surface, reduced backside damage, timely and efficient adaptation to changing equipment properties, improved yield, and reduced operating costs. Aspects of the present disclosure include: applying a suction voltage to a susceptor; applying the suction voltage to the susceptor using a preselected value; ramping the suction voltage up until an impedance shift occurs; detecting the impedance shift; determining a precise suction voltage based on the impedance shift; and adjusting the applied suction voltage to the precise suction voltage.

[0046] It is contemplated that one or more of the aspects disclosed herein may be combined. In addition, it is contemplated that one or more of the aspects may include some or all of the aforementioned benefits.

[0047] Although the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be designed without departing from the basic scope of the present disclosure. The present disclosure also contemplates that one or more aspects of the embodiments described herein may be replaced by one or more of the other aspects described. The scope of the present disclosure is determined by the appended claims.

Claims

1. A method for adsorbing one or more substrates in a substrate processing chamber, comprising: applying a clamping voltage to a susceptor, wherein the substrate is disposed on a supporting surface of the susceptor; ramping the clamping voltage from the applied voltage; detecting an impedance shift while ramping the clamping voltage; determining a corresponding clamping voltage when the impedance shift occurs; as well as An exact clamping voltage is determined based on the impedance shift and the corresponding clamping voltage.

2. The method of claim 1, wherein the impedance shift is an impedance shift of an RF energy generator that supplies RF energy to the substrate processing chamber.

3. The method of claim 1 , wherein said detecting said impedance shift comprises measuring said impedance shift, and said method further comprises: The precise clamping voltage is applied during the deposition process.

4. The method of claim 1, wherein applying the clamping voltage to the base comprises: The clamping voltage is ramped up until the impedance shift occurs.

5. The method of claim 1, wherein the precise adsorption voltage is a minimum voltage value for adsorbing the substrate to the supporting surface of the susceptor, the precise adsorption voltage reduces a bending of the substrate, and the method further comprises generating plasma.

6. The method of claim 1, wherein said applying said clamping voltage to said pedestal, said detecting said impedance shift, and said determining said precise clamping voltage are repeated for one or more additional substrates.

7. A method for adsorbing one or more substrates in a substrate processing chamber, comprising: applying a clamping voltage to a pedestal by ramping the clamping voltage toward a preselected value, wherein the substrate is disposed on a supporting surface of the pedestal; detecting an impedance shift while ramping up the clamping voltage; determining a precise clamping voltage based on the impedance shift; as well as The precise clamping voltage is used to adjust the applied clamping voltage.

8. The method of claim 7, wherein the impedance shift is an impedance shift of an RF energy generator that supplies RF energy to the substrate processing chamber.

9. The method of claim 7, wherein said detecting said impedance shift comprises: The impedance shift is measured.

10. The method of claim 7, further comprising performing a deposition process.

11. The method of claim 7, further comprising: The clamping voltage is ramped up toward the preselected value until the impedance shift occurs.

12. The method of claim 7, wherein the precise adsorption voltage is a minimum voltage value for adsorbing the substrate to the supporting surface of the susceptor, the precise adsorption voltage reduces a bending of the substrate, and the method further comprises generating plasma.

13. The method of claim 7, wherein the applying the clamping voltage to the pedestal, the detecting the impedance shift, and the determining the precise clamping voltage are repeated for one or more additional substrates.

14. A controller for a substrate processing chamber system, comprising: processor; as well as A set of computer instructions which, when executed, instruct the processor to: causing a DC voltage generator to apply a clamping voltage to the base and ramping the clamping voltage from the applied value, causing an impedance detector to detect an impedance shift of a component of a substrate processing chamber while ramping the clamping voltage, and The precise clamping voltage is determined based on the impedance shift.

15. The controller of claim 14, wherein the set of computer instructions, when executed, directs the processor to store the precise clamping voltage in a memory.

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