Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
  • H01J37/32082—Radio frequency generated discharge
  • H01J37/32174—Circuits specially adapted for controlling the RF discharge
  • H01J37/32183—Matching circuits
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/35—Sputtering by application of a magnetic field, e.g. magnetron sputtering
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
  • H01J37/32082—Radio frequency generated discharge
  • H01J37/32174—Circuits specially adapted for controlling the RF discharge
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
  • H03H7/38—Impedance-matching networks
  • H03H7/40—Automatic matching of load impedance to source impedance

Definitions

• PVD physical vapor deposition
• RF radio frequency
• Chip makers and tool makers use chambered gases and radio frequency (“RF”) waves to discharge the gases to generate plasma.
• PVD physical vapor deposition
• PVD systems are used to deposit thin layers of a target material onto a substrate.
• PVD systems generally include a RF generator that transmits a signal to a deposition chamber.
• An RF match having a variable impedance is generally located between the RF generator and the chamber.
• RF waves arrive from the RF generator passing through a cable, through the matching network, and then to the plasma chamber.
• the purpose of the matching network is to make the chamber and the RF match set to a particular impedance, such as 50 Ohms.
• the RF match may be tuned, i.e., the impedance may be varied, to make the impedance of the RF match be the complex conjugate of the deposition chamber's impedance. Tuning the RF match reduces reflected power from the chamber, thereby increasing the power transferred from the RF generator to the chamber and into the plasma deposition process.
• FIG. 1 illustrates an exemplary physical vapor deposition system, according to one or more embodiments described.
• FIG. 2 illustrates an exemplary matching network from FIG. 1 , according to one or more embodiments described.
• FIG. 4 illustrates an exemplary table describing combinations of phase and mag capacitor control combinations.
• FIG. 5 illustrates exemplary graphs depicting variable positioned tuning and load capacitor and resulting reflected power.
• FIG. 6 illustrates exemplary graphs depicting variable positioned tuning and load capacitor and resulting reflected power.
• Embodiments of the disclosure may further provide a matching network system including an input sensor coupled to a controller.
• the controller sending a signal to the second motor, adjusts the position of the tuning capacitor based on the magnitude error.
• the controller determines whether a deadzone has occurred in the matching network. If a dead-zone has occurred in the first tuning mode, then the controller performs a second tuning mode. In the second tuning mode, the position of the tuning capacitor is based on a first composite value of the magnitude error value and the phase error value. Also, the position of the load capacitor is based on a second composite value of the magnitude error value and the phase error value.
• the matching network system determines whether the matching system has reached a tuned state, and if the matching network system has reached a tuned state, then it performs the first tuning mode. The matching network remains in the first tuning mode until another dead-zone is determined to have occurred, and then switches to the second tuning mode to move the network out of the dead-zone.
• a shield 126 may at least partially surround the pedestal 120 and the substrate 122 and be electrically grounded, for example, by physical attachment to the chamber body 112.
• the shield 126 is generally configured to receive deposition particles that would normally deposit on the interior walls of the chamber 110 during the PVD process.
• a gas supply 128 may be coupled to the chamber 110 and configured to introduce a controlled flow of a process gas into the chamber 110.
• the process gas introduced to the chamber 110 may include Argon (Ar), Nitrogen (N2), Hydrogen (H2), Helium (He), Xenon (Xe), a combination thereof, or the like.
• a vacuum pump 130 may be coupled to the chamber 110 and configured maintain a desired sub-atmospheric pressure or vacuum level in the chamber 110. In at least one embodiment, the vacuum pump 130 may maintain a pressure of between about 1 millitorr and about 100 millitorrs in the chamber 110 during a deposition process.
• a first radio frequency (“RF") generator 140 may be configured to supply an AC process signal 141 at a frequency F1 to the chamber 110. In at least one embodiment, F1 may be between about 30 Hz and about 300 MHz. For example, F1 may be between about 30 MHz and about 162 MHz.
• a first RF match system 142 may be coupled to the RF generator 140 and configured to decrease reflected power from the load, i.e.
• the RF match system 142 may be or include an RF matching network 1 4 having a variable impedance.
• the power transfer from the first RF generator 140 to the chamber 110 via the RF matching network 144 is maximized when the impedance of the RF matching network 144 is adjusted to equal or approximate the complex conjugate of the impedance of the chamber 110.
• the RF generator 140 will see an impedance of about 50 ohms at the input of the RF matching network 144.
• a detector circuit 146 may be coupled to or disposed within the RF match system 142.
• the detector circuit 146 may be configured to detect or sense the process signal 141 from the RF generator 140 and to generate a magnitude error signal and a phase error signal.
• a match controller 148 may be coupled to the RF matching network 144 and the detector circuit 146. In at least one embodiment, the match controller 148 may be coupled to or be part of the RF match system 142. In another embodiment, the match controller 148 may be coupled to or be part of an overall system controller 180. The match controller 148 may be configured to adjust the impedance of the RF matching network 144 in response to the magnitude and phase error signals from the detector circuit 146 to decrease reflected power from the chamber 110.
• a DC generator 150 may supply a DC signal 151 to the chamber 110.
• a DC filter 152 may be coupled to the DC generator 150 and configured to block or prevent the process signal 141 and corresponding harmonics from the RF generator 140 from reaching and damaging the DC generator 150.
• a system controller 180 may be coupled to one or more of the gas supply 128, the vacuum pump 130, the RF generators 140, 160, 170, and the DC generator 150. In at least one embodiment, the system controller 180 may also be coupled to one or more of the RF match systems 142, 162, 172. The system controller 180 may be configured to control the various functions of each component to which it is coupled. For example, the system controller 180 may be configured to control the rate of gas introduced to the chamber 110 via the gas supply 128. The system controller 180 may be configured to adjust the pressure within the chamber 110 with the vacuum pump 130. The system controller 180 may be configured to adjust the output signals from the RF generators 140, 160, 170, and/or the DC generator 150. In at least one embodiment, the system controller 180 may be configured to adjust the impedances of the RF match systems 142, 162, 172.
• FIG. 2 illustrates an exemplary matching network 200 of this disclosure.
• the sensor may be coupled to the detector circuit 146, or to the RF generator 140.
• the input sensor 202 measures current, voltage and the phase of the incoming RF signal at the input point 202.
• the input sensor 204 is coupled to a controller 228, such as a computer or processor.
• the controller 228 receives the phase and magnitude signal from the input sensor 204.
• the controller 228 is coupled to a first motor 214 and to a second motor 216.
• the controller 228 and first and second motors 214, 216 are located within a control compartment 224.
• the controller 228 as further described below operates the first and second motors 214, 216.
• the controller 228 sends a signal 220 to the first motor 214 which is operatively coupled to the variable load capacitor (C1 ) 206, thereby adjusting the positional setting of the load capacitor 206.
• C1 variable load capacitor
• the controller 228 sends a signal 222 to the second motor 216 which is operatively coupled to the variable tuning capacitor (C2) 208, thereby adjusting the positional setting of the tuning capacitor 208.
• the load capacitor 206 and tuning capacitor 208 are located within an RF compartment 218.
• the tuning capacitor 208 is coupled in series to an inductor L1 210 which is coupled to an RF output 212.
• the controller 228 may perform one or more modules, programs or instructions for determining the magnitude error and the phase error, and for instructing the first and second motors 21 , 216 to position the variable load and tuning capacitors 206 and 208.
• the modules, programs or instructions may be stored in firmware, or other storage media.
• the controller operates in a first, second and third tuning modes. Additional, n-modes may be performed for the specific application of the matching network.
• FIG. 3 illustrates an exemplary method 300 for varying an impedance of an RF matching network, according to one or more embodiments described.
• the method 300 starts, as at 310, and the match network operates in a first mode while performing tuning 320 of the variable capacitors individually based on mag error or phase error.
• the controller determines 330 whether the matching network is in a dead-zone (for example in a state of railing or oscillation). At 340, if the matching network is not in a dead-zone, then the controller continues to operate in mode 1. If the matching network is determined to be in a dead-zone, then the controller switches operation to a second mode.
• a dead-zone for example in a state of railing or oscillation
• the match network operates in the third mode and performs tuning 380 of the variable capacitors based on composite mag error and phase error values.
• the controller determines 390 whether the matching network is in a dead-zone. At 395, if the matching network is not in a dead-zone, then the controller switches operation back to mode 1. If the matching network is determined to be in a dead-zone the matching network may switch to additional n modes trying to kick the tuning network out of a dead-zone. The controller will then revert back to mode 1 if the network is no longer in a dead-zone.
• the controller 228 operates in a first mode, or a normal operating mode, where the controller positions the variable load and tuning capacitors 206 and 208.
• the controller 228 operates in this first mode to tune the matching network 200 to reduce reflected power to as close to zero kilowatts as possible.
• the tuning process works for most of the tuning area.
• the variable load and tuning capacitors 206 and 208 are set to an initial position, for example, both variable load and tuning capacitors 206 and 208 are set at 50% of their positional range.
• the controller 228 uses phase error and mag error to guide the variable load and tuning capacitors 206 and 208 then to a desired target position.
• the controller 228 uses one signal, either the phase error or mag error, to control one of the variable load and tuning capacitors 206 and 208, either C1 or C2.
• the controller 228 determines how fast or the rate at which the variable load and tuning capacitors 206 and 208 turn, and in which direction the variable load and tuning capacitors 206 and 208 turn. For example, the higher the error, the higher the rate at which a capacitor may turn, up to a predetermined maximum limit. In one embodiment, if the error is negative, the capacitance is reduced. And if the error is positive, capacitance is increased. The polarity usually drives the capacitors to the correct direction. For some cases, at some special comers, the controller 288 may drive either variable capacitor 206, 208 in an incorrect direction which may lead to an out-of-tune state, and cause railing or oscillation. In these instances, one of the variable capacitors 206, 208 is likely set at a very high or very low positional limit of the capacitor. And since the signal keeps driving to the variable capacitor 206, 208 to an opposite direction it cannot come back up.
• one of the variable load and tuning capacitors 206, 208 may stop at a position for a period of time and then oscillate around this position. If this happens, at the same time the reflected power may still be high, then would be considered as a dead-zone. Usually, the matching network 200 does not determine the occurrence of a dead-zone, until it happens.
• the controller 228 usually operates in a first mode, or normal operating mode for regular tuning.
• positive phase error controls C2 tunnel capacitor 208) and positive mag error controls C1 (load capacitor 206).
• the controller 228 monitors and determines whether a tuning failure occurs while operating in the first mode (for example, whether railing or oscillation is occurring). For, example the controller 228 may determine a tuning failure or dead-zone, when one of the variable capacitor 206, 208 stops moving before reaching the particular target load. In a normal tuning situation, the capacitors will move until reaching a target load. If a tuning failure is determined while operating in the first mode, then the controller 228 switches to a second mode for tuning.
• the controller 228 individually adjusts C1 and C2. Possibly C1 may be driven to a minimum position of 0% and C2 goes to maximum position of 100%.
• the incoming signal keeps driving C2 up, and the incoming signal keeps driving C1 down.
• the variable load and tuning capacitors 206 and 208 will stay in their position. The controller will evaluate this state and determine that the matching network is in a dead-zone.
• the controller 228 can mix a percentage of phase error and mag error to generate a new signal, then use two new signals to adjust C1 and C2.
• the controller 228 may adjust the tuning capacitor 208 based on a first composite value of the magnitude error value and the phase error value, and the load capacitor 206 based on a second composite value of the magnitude error value and the phase error value.
• the following formula describes the application of an embodiment of the second mode: [0049] a2*Phase_error+b2*Mag_error controls load capacitor (C1 );
• coefficient values may be a combination of fractional and integer values, such as 0.6*Phase_error- 0.4*Mag_error controls tune capacitor (C1 ), and 1 *Phase_error-0*Mag_error controls load capacitor (C2).
• a2 0.6
• b2 -0.4
• c2 1
• d2 0.
• the controller 228 adjusts the load capacitor 206 based on the value a2 multiplied by the phase error which is added to the value b2 multiplied by the mag error.
• the controller 228 adjusts the tuning capacitor 208 based on the value c2 multiplied by the phase error which is added to the value d2 multiplied by the mag error.
• the controller 228 adjusts the tuning and determines whether a reflected power value is within a predetermined range.
• the controller 228 switches back to the first mode and the controller 228 operates in the first mode until another tuning failure is determined. If another tuning failure is determined while operating in the second mode, then the controller 228 switches to the third mode.
• the controller 228 can mix a percentage of phase error and mag error to generate a new signal, then use two new signals to adjust C1 and C2.
• the controller 228 may adjust the tuning capacitor 206 based on a first composite value of the magnitude error value and the phase error value, and the load capacitor 206 based on a second composite value of the magnitude error value and the phase error value.
• the following formula describes the application of an embodiment of the third mode:
• a3, b3, c3, d3 are predetermined real coefficient values (positive or negative) to optimize tuning for some load range. Therefore, if the load falls into the load range, the third mode will drive the network out of dead-zone, and find the tuning point. Based on the phase error and mag error and the applied coefficient values, there may be one or more combinations of coefficient values that will take the matching network out of a dead-zone.
• the controller 228 adjusts the load capacitor 206 based on the value a3 multiplied by the phase error which is added to the value b3 multiplied by the mag error.
• the controller 228 adjusts the tuning capacitor 208 based on the value c3 multiplied by the phase error which is added to the value d3 multiplied by the mag error.
• the controller 228 adjusts the tuning and determines whether a reflected power value is within a predetermined range.
• the controller 228 switches back to the first mode and the controller 228 operates in the first mode until another tuning failure is determined. If another tuning failure is determined while operating in the third mode, then the controller 228 switches to successful n modes.
• switching between modes generally refers to switching the type of tuning algorithm is used when the algorithm associated with a current mode no longer appears to be optimal. For example, a dead-zone for the current algorithm has been reached and therefore changing the algorithm (e.g., switching to a different mode) will allow the tuning to progress away from the current dead-zone.
• the concept of a blended mode may be introduced. In a blended mode implementation, there is no switching between modes per se as multiple algorithms from the different available modes (discussed above) may be concurrently applied and the effect of each algorithm to the tuning operation may be weighted. That is, the algorithm from the first mode may have a 50% effect and the algorithms from what would have been modes 2 and 3 would each have a 25% effect. Hence the concept of blended modes wherein different modes are used concurrently with different (and adjustable) weighting factors.
• Blended modes represent a variation of the above disclosed techniques for the phase error and mag error tuning algorithm for automatic RF impedance matching networks. Blended modes may seek to mitigate failures to converge on a tuning point. As discussed above, the operating space where this failure occurs is referred to colloquially as a “dead zone”. In operation, upon detection that a match tuning function has entered a dead zone, the blending mode technique for the overall tuning algorithm continuously varies the degree to which the composite error signals of the second tuning mode and the unaltered error signals of the first tuning mode are used within the single blended mode. That is, a weighted portion of the first mode tuning technique is used concurrently with a correspondingly weighted portion of the second mode tuning technique.
• the weighting can be varied over time such that at some times the first mode tuning technique will be more impactful (weighted greater than 50%) when the second mode tuning technique is less impactful (weighted less than 50%).
• the weighting may span anywhere from 0% (no impact at all) to 100% (total control) and any number of modes may be weightingly blended at a given time. In general, the sum of the weights should equal a whole number such as 1 (to reflect 100%).
• an additional scaling factor is incorporated into the equation that removes the influence of the composite error signals as the match converges on its tune point.
• This additional scaling factor is essentially proportional to the reflection coefficient of the match, gamma.
• conditional statements applied to the error signals of X1 and X2.
• This technique may perform more efficiently for L type matching networks because of their simplicity and efficiency (although it may be applied to any type of matching network).
• This example is used because L type matching networks tend to have dead zones in one specific area of their tuning range, where the polarity of the phase and magnitude of voltage and current at the input of the match are the opposite of the phase and magnitude of the voltage and current flowing out of the output of the match.
• other topologies will have dead zones in different areas.
• the use of conditional statements allows for the flexibility to address dead zones in various network topologies while minimizing undesirable effects, such as creating dead zones or elongating tuning trajectories.
• One example of using a conditional statement is as follows:
• Predetermined coefficient values for a2, b2, c2, and d2 for a3, b3, c3, d3 may be stored in a data storage device or memory in table form, database, or otherwise. Also, the coefficient values may be input manually though a user interface, or a command line function or tool. The predetermined coefficient values can be any combination of whole number, or fractions such as .5, 1.5, etc.
• coefficient values may be associated with characteristics of a particular chamber.
• coefficient values may be predetermined for different chamber configurations and stored in memory for use by the tuning modes.
• a matrix of nine chamber configurations could be stored in memory with associated coefficient values: 1 ) high resistance I high reactance, 2) high resistance / medium reactance, 3) high resistance I low reactance, 4) medium resistance I high reactance, 5) medium resistance / medium reactance, 6) medium resistance / low reactance, 7) low resistance / high reactance, 8) low resistance I medium reactance, and 9) low resistance / low reactance.
• FIG. 4 illustrates an exemplary table (Table 1 ) describing combinations of phase and mag capacitor control combinations for varying resistance and reactance conditions.
• Table 1 a table describing combinations of phase and mag capacitor control combinations for varying resistance and reactance conditions.
• column “Zi” identifies resistance and reactance.
• the column “Tuned” identifies whether the network tuned, and the column “Time” describes the amount of time to tune.
• the column “Chart” refers to corresponding graphs depicted in Figures 5, 6 and 7.
• Phase is C2+
• Mag is C1 + as one of the control combinations.
• Phase is C1 +
• Mag is C2- as one of the control combinations.
• the value “20-j40” refers to a high resistance (which is 20), and a high reactance (which is -40).
• the network tuned with a time to tune of 2.8 seconds. The results of these tuning parameters are depicted in Chart 504 referenced in Figure 5.
• Phase is C1 +
• Mag is C2- as one of the control combinations.
• Zi the value “,5+j40” refers to a low resistance (which is 0.5), and a high reactance (which is 40).
• the network tuned with a time to tune of 3.5 seconds. The results of these tuning parameters are depicted in Chart 710 referenced in Figure 7.
• each chart 502, 504, 506, 508, 510, 512, 602, 604, 606, 608, 610, 612, 702, 704, 706, 708, 710 and 712 depicts positional settings for the load capacitor (C1 ) 206 and the tuning capacitor (C2) 208, and the reflected power for each of the capacitor positional settings over a period of time.
• the allowable capacitor positional settings range from 0% to 100%. The higher the positional setting, the higher the capacitance for the capacitor.
• Positional adjustment of the load capacitor and tuning capacitor affect the reflected power from the load.
• the reflected power is displayed in kilowatts.
• Each chart depicts Time in milliseconds. The desired goal of tuning the match network is to drive the reflected power as close to zero kilowatts as possible.
• the load capacitor (C1 ) and the tuning capacitor (C2) are initially set to 50% of their positional range.
• first and second features are formed in direct contact
• additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.
• exemplary embodiments presented above may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.
• Such software code may be stored, partially or fully, on a memory device of the executing computing device.
• Software instructions may be embedded in firmware, such as an EPROM.
• hardware modules may be comprised of connected logic units, such as gates and flip-flops, and/or may be comprised of programmable units, such as programmable gate arrays or processors.
• the modules described herein are preferably implemented as software modules, but may be represented in hardware or firmware. Generally, the modules described herein refer to logical modules that may be combined with other modules or divided into sub-modules despite their physical organization or storage.
• Electronic data sources can include databases, volatile/non-volatile memory, and any memory system or subsystem that maintains information.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Plasma Technology (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=87884150

Family Applications (1)

Country Status (2)

Citations (5)

• 2023
  • 2023-02-28 WO PCT/US2023/014109 patent/WO2023167854A1/en unknown
  • 2023-03-02 TW TW112107649A patent/TW202341818A/zh unknown

Patent Citations (5)

Also Published As

Similar Documents

Legal Events