Systems and methods for compensating for RF power losses

Abstract

SOLUTION: Systems and methods for compensating for radio frequency (RF) power loss are disclosed. One of the methods includes conducting a no plasma test to determine resistance associated with output of an impedance matching circuit. After conducting the no plasma test, a substrate is processed in a plasma chamber. During processing of the substrate, power loss associated with the output of the impedance matching circuit is determined. The power loss is used to determine an amount of power to be delivered by a RF generator. The amount of power delivered is adjusted until the power loss is stabilized. The stabilization of the power loss facilitates uniform process of the substrate and additional substrates in the plasma chamber.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present embodiments relate to systems and methods for compensating for radio frequency (RF) power losses. [Background technology]

[0002] The background art provided herein is intended to provide a general background to the present disclosure, and the work of the inventors named herein, to the extent described in this background art, along with aspects of the description that would not normally be considered prior art at the time of filing, are not admitted expressly or impliedly as prior art to the present disclosure.

[0003] The wafer is etched using a plasma tool that includes a radio frequency (RF) generator, a matching network or matcher, and a plasma chamber. The RF generator is connected to the matcher via a coaxial cable, and the matcher is connected to the plasma chamber via a transmission line. The wafer is placed in the plasma chamber.

[0004] Once the wafer is positioned, the RF generator is turned on to provide RF power to the plasma chamber through a matcher and a transmission line. A process gas is also supplied to the plasma chamber. When the process gas is ignited by the RF power, a plasma is ignited in the plasma chamber. The plasma is used to etch the wafer.

[0005] It is against this background that the embodiments described in this disclosure arise. Summary of the Invention

[0006]

[0009] Embodiments of the present disclosure provide a system, an apparatus, a method, and a computer program product for compensating for radio frequency (RF) power loss. It should be understood that the present embodiments can be embodied in various forms, such as a process, an apparatus, a system, hardware, or a method recorded on a computer-readable medium. Some embodiments are described below.

[0007] Some semiconductor processing tools (such as conductor etch (CE) tools) perform subsystem biasing in a voltage control mode and some in a power control mode. The voltage control mode does not utilize power compensation operation. In the power control mode, chamber-to-chamber differences in parasitic power losses create variations in the power coupled to the plasma load. To provide optimal chamber matching performance, the variations in coupled power are minimized.

[0008] The systems and methods described herein provide compensation techniques for achieving corrective action to reduce variations in coupled power between chambers. The systems and methods relate to a chamber matching power compensation scheme for a bias subsystem. The compensation scheme is applied to a bias subsystem operating in power control mode. The compensation scheme utilizes a current probe placed at the output of a bias matching network. Current measurements received from the current probe allow for real-time calculation of parasitic power losses from the bias matching network to the plasma, or are used to compensate for the power losses. These parasitic power losses are removed using a modified control loop that continuously updates the power setpoint of the RF generator. The corrective action provides an offset to the power setpoint equal to the parasitic power losses along the RF delivery path in real time.

[0009] In some embodiments, a two-step procedure is implemented to account for parasitic power losses in the bias matching network and RF supply assembly. The procedure utilizes a probe (such as a current probe, voltage-current probe, impedance measurement probe, or impedance scanning probe) placed at the output of the bias matching network. First, the root-mean-square (RMS) current is measured by the probe during a no-plasma test (NPT). The equivalent series resistance (ESR) value of the bias matching network and the entire assembly is calculated by performing a linear regression on the square of the measured RMS current and the power delivered by the RF generator. The ESR value is stored by the host computer and used as a system constant.

[0010] Second, a control algorithm is implemented to provide real-time corrective action to the recipe power setpoint (e.g., P_sp_rec) of the RF generator using the ESR value measured above. When a recipe step is being executed, the power loss (e.g., P_loss) can be calculated at each time increment or time step i using the following equation: P_loss(i)=ERS*(I_RMS(i)) 2 ···(1) where I_RMS(i) is the RMS current read by the probe at time increment i. The power loss for the current time step is carried forward and added to the RF generator recipe power setpoint P_sp_rec to determine the updated generator power setpoint (e.g., P_sp_gen), where "sp" represents the setpoint and "gen" represents the RF generator. The following equation shows the updated generator power setpoint at that time increment: P_sp_gen(i)=P_sp_rec+P_loss(i-1)...(2) The procedure is repeated until the correction offset P_loss(i) is equal to the measured loss P_loss(i-1), at which point the parasitic power losses are taken into account.

[0011] Some advantages of the systems and methods described herein for compensating for RF power loss (e.g., parasitic power loss) include achieving chamber repeatability when processing one or more substrates. An RF generator supplies RF power to an electrode in a plasma chamber. The RF power is transmitted from the RF generator to the electrode via an RF path. Some RF power is lost along the RF path due to characteristics of the components in the RF path. Examples of components include an RF cable, an impedance matching circuit, and an RF transmission line. The RF cable connects the RF generator to an impedance matching circuit (e.g., a bias matching network). The RF transmission line connects the impedance matching circuit to the plasma chamber. The power delivered by the RF generator is adjusted to account for the RF power loss in the RF path. The power delivered by the RF generator is adjusted until the RF power loss stabilizes. After the RF power loss stabilizes, the RF generator is controlled to deliver the same or substantially the same amount of delivered power. When the same or substantially the same amount of power is delivered by the RF generator, one or more substrates are processed uniformly. For example, a uniform etch rate or a uniform deposition rate may be achieved when processing multiple substrates. As another example, the substrates may be desirably processed to achieve a uniform etch rate or a uniform deposition rate.

[0012] Other aspects will become apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0013] The embodiments are understood by reference to the following description taken in conjunction with the accompanying drawings.

[0014] [Figure 1] FIG. 1 illustrates one embodiment of a system to illustrate a plasma-free test performed before processing a substrate.

[0015] [Figure 2] FIG. 2 shows an embodiment of a graph to illustrate the determination of a resistance (such as an equivalent series resistance (ESR)) associated with the output of an impedance matching circuit.

[0016] [Figure 3] FIG. 1 illustrates one embodiment of a system to illustrate the use of resistance in determining the amount of power generated and delivered by a radio frequency (RF) generator to account for power losses associated with impedance matching circuits and transmission lines.

[0017] [Figure 4] FIG. 10 illustrates one embodiment of a table to explain how, during processing of a substrate, a processor continues to modify the amount of power delivered by the RF generator based on the amount of power loss associated with the output of the impedance matching circuit.

[0018] [Figure 5] FIG. 10 shows an embodiment of a graph to illustrate the variation of power delivered by an RF generator taking into account the loss of power delivered at the output of an impedance matching circuit.

[0019] [Figure 6] FIG. 1 illustrates an embodiment of a system to explain the application of a method for compensating for loss of transmitted power.

[0020] [Figure 7] FIG. 5 illustrates one embodiment of a system to illustrate that the amount of delivered power determined by applying the method described with respect to FIG. 4 is maintained for processing another substrate. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following embodiments describe systems and methods for compensating for radio frequency (RF) power loss. It will be apparent that the embodiments may be practiced without some or all of these specific details. Furthermore, detailed descriptions of well-known process operations have been omitted to avoid unnecessarily obscuring the embodiments.

[0022] 1 illustrates one embodiment of a system 100 for illustrating plasma-free testing performed prior to processing a substrate. The system 100 includes several components, such as an RF generator 102, an impedance matching circuit 104, a current sensor 106, a plasma chamber 108, and a host computing device 110.

[0023] Examples of the RF generator 102 include a kilohertz (kHz) RF generator or a megahertz (MHz) RF generator. An example of a kHz RF generator is an RF generator having an operating frequency of 400 kHz. Examples of a MHz RF generator include an RF generator having an operating frequency of a 1 MHz RF generator, a 2 MHz RF generator, a 13.56 MHz RF generator, a 27 MHz RF generator, or a 60 MHz RF generator. The RF generator 102 includes a processor, such as a digital signal processor (DSP), a driver / amplifier circuit, and an RF power supply. The processor is connected to the driver / amplifier circuit, which is connected to the RF power supply. An example of the RF power supply includes an RF oscillator.

[0024] Examples of the impedance matching circuit 104 include circuits having a network of circuit components connected in series or in parallel with each other. Examples of the circuit components include resistors, inductors, and capacitors. For example, the circuit components may be shunt capacitors or series capacitors.

[0025] The plasma chamber 108 is a parallel-plate plasma chamber (e.g., a capacitively coupled plasma (CCP) chamber). The plasma chamber 108 includes a chuck 112 and an upper electrode 114 facing the chuck 112. An example of the chuck 112 includes an electrostatic chuck (ESC) including a lower electrode and a ceramic plate disposed on top of the lower electrode. The chuck 112 and the upper electrode 114 are each formed from a metal such as aluminum or an aluminum alloy. The upper electrode 114 is connected to ground potential.

[0026] Examples of the current sensor 106 include a voltage-current (VI) probe, a current probe, an impedance sensor, an impedance scanner, or an impedance probe. Examples of the host computing device 110 include a computer and a server. The computer may be a desktop computer, a laptop computer, a smartphone, or a tablet. The host computing device 110 includes a processor 120 and a memory device 122. Examples of processors used herein include a central processing unit (CPU), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a controller, a microprocessor, and a microcontroller. Examples of memory devices include random access memory (RAM) and read-only memory (ROM). For example, the memory device is flash memory or a redundant array of independent disks (RAID). The memory device 122 is connected to the processor 120 via a connection such as a serial transfer connection, a parallel transfer connection, a bus, or a universal serial bus (USB) connection.

[0027] The RF generator 102 is connected to the impedance matching circuit via an RF cable 116. For example, an output O1 of the RF power supply of the RF generator 102 is connected to an input I2 of the impedance matching circuit 104 via the RF cable 116. The impedance matching circuit 104 is also connected to the lower electrode of the chuck 112 via an RF transmission line 118. For example, an output O2 of the impedance matching circuit 104 is connected to the lower electrode via the RF transmission line 118. The RF transmission line 118 is another example of a component of the plasma system 100, and includes an RF rod, an insulator, and a sleeve. The insulator encases the RF rod, and the sleeve forms a protective cover surrounding the insulator.

[0028] The processor 120 is connected to the input I1 of the RF generator 102 via a connecting cable 125, such as a serial transfer cable, a parallel transfer cable, an Ethernet cable, or a USB cable. For example, the processor 120 is connected to the processor of the RF generator 102 via the connecting cable 125. The current sensor 106 is connected to the output O2 of the impedance matching circuit 104 via an RF cable and is connected to the processor 120 via the connecting cable 121. Examples of connecting cables have been described above.

[0029] During plasma-free testing, no plasma is generated within the plasma chamber 108. For example, one or more process gases (such as a fluorine-containing gas or an oxygen-containing gas) are not supplied to the plasma chamber 108 to ignite a plasma within the plasma chamber 108. Also, in this example, no substrate is placed on top of the chuck 112 for processing.

[0030] Processor 120 provides a command signal having a quantity of one or more variables (such as frequency and transmitted power) to RF generator 102 via connecting cable 125 and input I1. The transmitted power is the sum of the supplied power and the power loss that occurs in RF cable 116. The supplied power is the power that would be generated by RF generator 102 without receiving a command signal having the quantity of transmitted power. For example, the supplied power is the power that would be delivered by RF generator 102 at output O1 if power losses in RF cable 116 were not taken into account. The quantities of the variables are stored in memory device 122 for access by processor 120.

[0031] The RF generator 102 receives a command signal having a variable amount and generates an RF signal 124. For example, a processor in the RF generator 102 receives a command signal having a variable amount from the processor 120 and generates a signal having those amounts. The processor in the RF generator 102 provides the signal to a driver / amplifier circuit in the RF generator 102. A driver (e.g., one or more transistors) in the driver / amplifier circuit generates a current signal upon receiving the signal from the processor in the RF generator 102. The amplifier in the driver / amplifier circuit amplifies the power signal and outputs an amplified current signal, which is then sent to the RF power supply of the RF generator 102. The RF power supply oscillates to generate an RF signal 124 having a variable amount. The RF signal 124 is provided by the RF generator 102 to the impedance matching circuit 104 via output O1, RF cable 116, and input I2.

[0032] The impedance matching circuit 104 matches the impedance of a load connected to the output O2 of the impedance matching circuit 104 to the impedance of a source connected to the input I2 of the impedance matching circuit 104, and outputs a modulated RF signal 126 at the output O2. Examples of a load include an RF transmission line 118 and a plasma chamber 108. Examples of a source include an RF cable 116 and an RF generator 102.

[0033] The modulated RF signal 126 is transmitted to the lower electrode of the chuck 112 via RF transmission line 118. While the modulated RF signal 120 is provided or supplied at the output O2 during a plasma-free test, the current sensor 106 measures the amount of current (e.g., root mean square current (Irms)) being supplied at the output O2. Current is an example of a parameter. Each amount of current measured by the current sensor 106 is the root mean square (rms) of multiple amounts of current supplied at the output O2. The current sensor 106 provides the measurement of the amount of current (e.g., Irms) at the output O2 to the processor 120 via a connecting cable 121.

[0034] The processor 120 receives the measured value of the amount of current and generates a database (e.g., a table or list) containing a correspondence between the amount of current and the amount of delivered power at which the amount of current Irms is measured. For example, when the processor 120 controls the RF generator 102 to generate an RF signal 124 having a delivered power of an amount Pdel1, the current sensor 106 measures the amount of current Irms1 supplied at the output O2. The delivered power is another example of a parameter. The processor 120 stores the correspondence (e.g., a one-to-one relationship, a connection, an association, or a mapping) between the amounts Pdel1 and Irms1 in a database, which is stored in the memory device 122. Similarly, when the processor 120 controls the RF generator 102 to generate an RF signal 124 having a delivered power of another amount Pdel2, the power sensor 106 measures another amount Irms2 of current supplied at the output O2 and provides the amount Irms2 to the processor 120 via the connecting cable 121. Processor 120 stores the correspondence between the quantities Pdel2 and Irms2 in a database. In this manner, multiple correspondences between the amount of power delivered by RF generator 102 in RF signal 124 and the amount of current measured at output O2 over time period t are created or determined by processor 120 and stored in a database.

[0035] Note that the processor 120 calibrates the RF generator 102 to determine the amount of power P_del (P_del1, P_del2, etc.) delivered by the RF generator 102 at the output O1. For example, the RF generator 102 is connected to a dummy load, such as a 50 ohm load, via the RF cable 116. The dummy load is also referred to herein as a known load. A measurement device (such as a voltage and current sensor or a power sensor) is connected to the input of the dummy load and to the processor 120. The processor 120 generates a command signal to control the RF generator 120 to provide an RF signal at the output O1. Upon receiving the command signal, the RF generator 102 generates an RF signal and provides it to the dummy load via the output O1 and the RF cable 116. The measurement device measures the amount of power at the input of the dummy load. The amount of power measured at the input indicates the amount of power lost in the RF cable 116. To determine the amount of power delivered by RF generator 102, processor 120 receives the measured amount of power and determines a correspondence between the amount of power delivered by RF generator 102 and the amount of power measured at the input of the dummy load. For example, processor 120 determines the difference between the amount of power delivered by RF generator 102 at output O1 and the amount of power measured at the input of the dummy load. The difference is equal to the amount of power lost in RF cable 116. Processor 120 adds the difference to the amount of power delivered by RF generator 120 to calculate the amount of power (e.g., Pdel1) delivered by RF generator 120. Processor 120 stores in a database a correspondence (e.g., a one-to-one relationship, a connection, an association, or a mapping) between the amount of power delivered by RF generator 120 (e.g., Psup1) and the amount of power delivered by RF generator 122 (e.g., Pdel1) to account for power loss in RF cable 116. In this way, a database is created by the processor 120 having a plurality of amounts of delivered power (Pdel1, Pdel2, etc.) at output O1 and having a plurality of amounts of supplied power (Psup1, Psup2, etc.) at output O1.The database contains a correspondence between the amount of power supplied by RF generator 102 at output O1 and the amount of power delivered by RF generator 102 at output O1.

[0036] It should be noted that the power P_del delivered at the output O1 is also referred to herein as the power delivered at the input I2 of the impedance matching circuit 104, since the power P_del delivered at the output O1 is calibrated to take into account power losses in the RF cable 116.

[0037] In one embodiment, the impedance matching circuit may also be referred to herein as a matcher, a matching network, an impedance matching network, or a matching housing, and these terms are used interchangeably herein.

[0038] In one embodiment, instead of connecting the upper electrode 114 to ground potential, the lower electrode is connected to ground potential and the upper electrode 114 is connected to an RF transmission line 118. The RF transmission line 118 is connected to an output O2 of the impedance matching circuit 118 to receive the modulated RF signal 126.

[0039] In one embodiment, multiple processors are used in place of processor 120. For example, the functions described herein performed by processor 120 are instead performed in a distributed manner by multiple processors. Furthermore, multiple memory devices are used in place of memory device 122. For example, information stored in memory device 122 is stored in a distributed manner among the multiple memory devices.

[0040] In one embodiment, the functions described herein performed by processor 120 and the processor of RF generator 102 are instead performed by processor 120 or the processor of RF generator 102, or by three or more processors.

[0041] In one embodiment, in addition to the RF generator 102, one or more additional RF generators are connected to the impedance matching circuit 104. For example, the RF generator 102 is a kHz RF generator, and the additional RF generator includes two MHz RF generators. As another example, the RF generator 102 is a MHz RF generator, and the additional RF generator includes two MHz RF generators. The one or more additional RF generators are connected to one or more corresponding additional inputs of the impedance matching circuit 104 via one or more corresponding additional RF cables. The one or more additional RF generators generate one or more corresponding additional RF signals and provide the one or more additional RF signals to the impedance matching circuit 104 via one or more corresponding additional RF cables. The impedance matching circuit 104 matches the impedance of the load to the impedance of the source connected to the input I2 and the one or more corresponding additional inputs of the impedance matching circuit 104, and outputs a modulated RF signal at the output O2. Examples of sources connected to input I2 and the corresponding one or more additional inputs of impedance matching circuit 104 include one or more additional RF cables, RF cable 116, RF generator 102, and one or more additional RF generators.

[0042] In one embodiment, instead of being connected to output O2, current sensor 106 is connected to a point on RF transmission line 108 or to input 13 of chuck 112 to measure the amount of current being delivered at that point or input 13. In this embodiment, the amount of power loss occurring from output O1 of RF generator 120 to that point or input 13 on RF transmission line 108 is determined and compensated for.

[0043] 2 is one embodiment of a graph 200 for illustrating the determination of a resistance (e.g., equivalent series resistance (ESR)) associated with the output O2 of the impedance matching circuit 104 (FIG. 1). The resistance associated with the output O2 is constant and is a combination (e.g., sum) of the resistance of the RF cable 116 and the resistance of the circuit components of the impedance matching circuit 104. The circuit components of the impedance matching circuit 104 are connected between the input I2 and the output O2 of the impedance matching circuit 104.

[0044] Graph 200 plots in plot 202 the power delivered at output O1 of RF generator 102 on the y-axis and the square of the amount of current measured at output O2 corresponding to the delivered power on the x-axis (FIG. 1). The delivered power at output O1 is measured in watts (W). During or after a plasma-free test, processor 120 accesses (reads or retrieves) from memory device 122 the amount of delivered power at output O1 (e.g., Pdel1, Pdel2, etc.). For example, before processing a substrate, processor 120 accesses from memory device 122 the amount of delivered power at output O1. The square of the amount of current is Irms 2 The graph 200 plots the measured current at output O2 from the measured current amounts stored in the database. The graph 200 also calculates the square of the amount of current delivered ...

[0045] Also, during or after the no-plasma test, processor 120 may calculate in graph 200 the square of Irms1 of the amount of current delivered at output O2. 2 Plot the amount of power delivered at output O1, Pdel1, against the square of the amount of power delivered at output O2, Irms2 2For example, point 204A in graph 200 plots the amount of power delivered at output O2, Pdel2, versus the amount of power delivered at output O2, Pdel1, and Irms1. 2 Another point 204B in the graph 200 represents the quantities Pdel2 and Irms2 2 Similarly, graph 200 includes other points 204C, 204D, 204E, and 204F, each of which corresponds to the amount of power delivered at output O1 of RF generator 102 and the square of the amount of current delivered at output O2 of impedance match circuit 104.

[0046] During or after the plasma-free test, processor 120 generates plot 202 from points 204A, 204B, 204C, 204D, 204E, and 204F. For example, processor 120 performs a linear regression analysis to fit a line through points 204A, 204B, 204C, 204D, 204E, and 204F. Each point 204A-204F plots the amount of power delivered at output O1 against the square of the amount of current delivered at output O2.

[0047] Additionally, during or after the plasma-free test, processor 120 calculates the slope of plot 202. For example, processor 120 may identify points 204G and 204H located on plot 202, project point 204G horizontally onto the y-axis to determine the amount of delivered power P_delB at output O1 of RF generator 102, project point 204H horizontally onto the y-axis to determine the amount of delivered power P_delA at output O1 of RF generator 102, and calculate the square of the amount of current IrmsA at output O1 of RF generator 102. 2 Project point 204G vertically onto the x-axis to determine the square of the amount of current IrmsB at the output O1 of RF generator 102. 2 The processor 120 projects the point 204H perpendicularly onto the x-axis to determine a first difference between the quantities P_delB and P_delA and a quantity IrmsB. 2 and IrmsA 2and calculates the ratio of the first and second differences to determine the slope of the plot 202. The processor 120 stores the slope as the resistance ESR associated with the output O2 of the impedance matching circuit 104.

[0048] 3 illustrates one embodiment of a system 300 for illustrating the use of a resistance ESR associated with the output O2 of the impedance matching circuit 104 in determining the amount of power P_sp_gen(i+1) generated and delivered by the RF generator 102 to account for power losses associated with the RF cable 116 and the impedance matching circuit 104. The system 300 is structurally similar to the system 100 of FIG. 1. For example, the system 300 includes the same components as the system 100. For example, the system 300 includes the RF generator 102, the RF cable 116, the impedance matching circuit 104, the RF transmission line 118, the plasma chamber 108, the current sensor 106, and the host computing device 110.

[0049] The plasma chamber 108 contains a substrate S1 (such as a semiconductor wafer) to be processed. Examples of substrate processing include depositing one or more materials on the substrate, etching the substrate, sputtering the substrate, and cleaning the substrate. The substrate S1 is positioned on an upper surface of the chuck 112 for processing.

[0050] During a first time period represented by integer i, processor 120 generates a command signal having an amount of power P_sp_rec to be generated by RF generator 102 and output or delivered at output O1. The terms time period, time increment, and time step are used interchangeably herein. The quantity P_sp_rec is also referred to herein as a recipe setpoint for the operation of RF generator 102, where "sp" refers to the setpoint and "rec" refers to the recipe. Processor 120 accesses (e.g., reads) the quantity P_sp_rec from memory device 122. The recipe setpoint for the operation is provided to processor 120 by a user via an input device (e.g., a mouse, keyboard, or keypad) of host computing device 110. The input device is connected to processor 120 via a connecting cable.

[0051] Additionally, during the first period, the processor 120 transmits a command signal having the quantity P_sp_rec to the RF generator 102 via the connecting cable 125 and the input I1. Upon receiving the command signal, the RF generator 102 generates an RF signal 302 having a power of the quantity P_sp_rec and provides the RF signal 302 to the impedance matching circuit 104 via the output O1, the RF cable 116, and the input I2. During the first period, the RF signal 302 is generated in the same manner as the RF signal 124 (FIG. 1) is generated. For example, the processor of the RF generator 102 receives the command signal having the quantity P_sp_rec and generates a signal having that quantity. The processor of the RF generator 102 provides the signal having that quantity to a driver / amplifier circuit of the RF generator 102. The driver of the driver / amplifier circuit generates a current signal upon receiving the signal from the processor of the RF generator 102. The amplifier of the driver / amplifier circuit amplifies the power signal and outputs an amplified current signal, which is sent to an RF power supply of the RF generator 102. The RF power supply oscillates to generate and provide an RF signal 302 having a power of the amount P_sp_rec.

[0052] During a first time period, the impedance matching circuit 104 receives an RF signal 302 at input 12, matches the impedance of a load connected to output 02 to the impedance of a source connected to input 12, and outputs a modulated RF signal 304 at output 02. The impedance matching circuit 104 provides the modulated RF signal 304 to the lower electrode of the chuck 112 via output 02 and RF transmission line 118. Additionally, one or more process gases are supplied to the plasma chamber 108. With the one or more process gases supplied to the plasma chamber 108 and the modulated RF signal 304 received by the lower electrode of the plasma chamber 108, a plasma is ignited and sustained in the plasma chamber 108, and the plasma processes the substrate S1.

[0053] While the modulated RF signal 304 is provided at the output O2 during a first time period, the current sensor 106 measures a quantity I_RMS(i) of current delivered at the output O2, where i is an integer greater than or equal to zero. The quantity I_RMS(i) is the root mean square of multiple quantities of current delivered at the output O2. The current sensor 106 provides the quantity I_RMS(i) of current to the processor 120 via a connecting cable 121. While the substrate S1 is being processed, the processor 120 stores the quantity I_RMS(i) in a memory device 122, accesses (e.g., reads or retrieves) the quantity I_RMS(i) from the memory device 122, and calculates the square of the quantity I_RMS(i) of current during the first time period, I_RMS(i). 2 The processor 120 calculates the squared I_RMS(i) 2 Also, during a first period when the substrate S1 is being processed in the plasma processing chamber 108, the processor 120 retrieves from the memory device 122 the amount of resistance ESR associated with the output O2 and the value I_RMS(i) 2 and access (read or get) the square of the amount of current through the resistance ESR, I_RMS(i) 2to calculate or determine an amount P_loss(i) of RF power loss at output O2 of impedance matching circuit 104. The amount P_loss(i) is the sum of power loss in or due to RF cable 116 and power loss in or due to circuit components of impedance matching circuit 104 between input I2 and output O2 of impedance matching circuit 104. Within a first time period, processor 120 calculates a sum P_sp_gen(i+1) of the amount P_sp_rec and the amount P_loss(i) of power associated with output O2 and outputs the amount P_sp_gen(i+1), where “gen” refers to RF generator 102.

[0054] During the second time period when substrate S1 is being processed, instead of continuing to generate a command signal having the amount of power P_sp_rec, processor 120 generates a command signal having the amount of delivered power P_sp_gen(i+1) and sends the command signal to RF generator 102 via connecting cable 125 and input I1 to adjust (e.g., change or modify) the recipe setpoint P_sp_rec of operation of RF generator 102. As one example, the second time period is a time period following the first time period (e.g., a time period consecutive to the first time period). For example, there is no time period between the first time period and the second time period. As another example, the second time period follows the first time period after a certain amount of time.

[0055] Furthermore, during the second time period, upon receiving a command signal having an amount P_sp_gen(i+1), the RF generator 102 generates an RF signal 302 having the amount P_sp_gen(i+1) of delivered power at the output O1. The RF generator 102 processes the command signal having the amount P_sp_gen(i+1) to output an RF signal 302 having the amount P_sp_gen(i+1) in the same manner as described above for outputting an RF signal 302 having the amount P_sp_rec of power. For example, during the second time period, the processor 120 adjusts (e.g., modifies or changes) the recipe setpoint P_sp_rec to achieve the amount P_sp_gen(i+1) and provides a command signal having the amount P_sp_gen(i+1) to the RF generator 102 via the connecting cable 125. Upon receiving the command signal, the processor of the RF generator 102 generates and transmits a signal having the amount P_sp_gen(i+1) to the driver / amplifier circuit of the RF generator 102. Upon receiving the signal having the quantity P_sp_gen(i+1), the driver / amplifier circuit generates a current signal based on the quantity P_sp_gen(i+1) and provides the current signal to the power supply of the RF generator 102. The power supply of the RF generator 102 oscillates in accordance with the current signal to output an RF signal 302 having the quantity P_sp_gen(i+1).

[0056] An RF signal 302 having a transmitted power amount P_sp_gen(i+1) is supplied by the RF generator 102 to the impedance matching circuit 104 via the output O1, the RF cable 116, and the input I2. The impedance matching circuit 104 matches the impedance of the load connected to the output O2 with the impedance of the source connected to the input I2, and modulates the RF signal 302 having the transmitted power amount P_sp_gen(i+1), thereby outputting a modulated RF signal 304. The lower electrode receives the modulated RF signal 304, which is output based on the transmitted power amount P_sp_gen(i+1), for processing the substrate S1. The modulated RF signal 304 is received by the lower electrode via the output O2 and the RF transmission line 118.

[0057] Again during a second time period, current sensor 106 measures the amount of current delivered at output O2, I_RMS(i+1), and provides that amount to processor 120 via connecting cable 121. The processor stores the amount I_RMS(i+1) in memory device 122. During the second time period, processor 120 accesses (e.g., retrieves or reads) the amount I_RMS(i+1) from memory device 122 and determines or calculates an amount P_loss(i+1) of delivered power loss at output O2 by multiplying the square of the amount I_RMS(i+1) by the resistance ESR associated with output O2. Also during the second time period, processor 120 calculates the sum of the amount of power P_sp_rec and the amount of power loss P_loss(i+1) to output an amount of delivered power P_sp_gen(i+2).

[0058] During a third time period when substrate S1 is being processed, processor 120 controls RF generator 102 to generate an RF signal 302 having an amount P_sp_gen(i+2) of delivered power to adjust a recipe setpoint P_sp_rec for the power supplied at output O1. For example, during the third time period, processor 120 adjusts (e.g., modifies or changes) recipe setpoint P_sp_rec to achieve the amount P_sp_gen(i+2) and provides a command signal having the amount P_sp_gen(i+2) to RF generator 102 via connecting cable 125. Upon receiving the command signal from processor 120, the processor of RF generator 102 sends a signal having the amount P_sp_gen(i+2) to a driver / amplifier circuit of RF generator 102. Upon receiving the signal having the amount P_sp_gen(i+2), the driver / amplifier circuit generates a current signal based on the amount P_sp_gen(i+2) and provides the current signal to the power supply. The power supply oscillates according to the current signal to output an RF signal 302 having an amount P_sp_gen(i+2). The third time period is a time period subsequent to the second time period. In a similar manner, during further time periods during which the substrate S1 is being processed, the processor 120 continues to control the RF generator 102 to vary the amount of delivered power of the RF signal 302 to account for or compensate for power losses associated with the output O2 of the impedance matching circuit 104 (e.g., power losses at the output O2, etc.).

[0059] FIG. 4 illustrates one embodiment of a table 400 to illustrate how, during processing of substrate S1 or another substrate, processor 120 continues to modify the amount of delivered power at output O1 of RF generator 102 based on the amount of power loss associated with output O2 of impedance match circuit 104 (FIG. 3). Table 400 includes a list of time steps and a list of correction offsets to be applied to recipe setpoint P_sp_rec, the generator setpoint, the power loss P_loss associated with output O2, the amount of power coupled to the plasma in plasma chamber 108 (FIG. 1), and the correction offset for the next time step. Examples of power loss P_loss include P_loss(i) and P_loss(i+1). The power loss P_loss is used to adjust recipe setpoint P_sp_rec when the amount of power loss is added to the recipe setpoint P_sp_rec. The correction offsets, generator setpoint, power loss, amount of power coupled to the plasma, and correction offset for the next time step are measured in watts (W).

[0060] Examples of time steps include a first period, a second period, and a third period. For example, the first period is an example of time step 0, the second period is an example of time step 1, and the third period is an example of time step 2. As another example, the first period is an example of time step 4, the second period is an example of time step 5, and the third period is an example of time step 6. For example, the first period is an example of time step 3, the second period is an example of time step 4, and the third period is an example of time step 5.

[0061] Examples of generator setpoints include the quantity P_sp_rec as the initial generator recipe setpoint, the quantity P_sp_gen(i+1), and the quantity P_sp_gen(i+2). Further, examples of power losses associated with output O2 include the quantity P_loss(i) and the quantity P_loss(i+1). During each time step, the power loss associated with output O2 is equal to the correction offset for the next time step. For example, the correction offset is 5 W during time step 2, which is the same as the power loss of 5 W during time step 1.

[0062] During time step 0, processor 120 controls RF generator 102 to generate RF signal 302 (FIG. 3) having a magnitude of 500 W. The amount 500 W is an example of a recipe setpoint for power, P_sp_rec. Additionally, during time step 0, processor 120 accesses from memory device 122 an amount of delivered power loss, 5 W, associated with output O2. The amount of delivered power loss, 5 W, at output O2 is calculated by processor 120 by multiplying the square of the amount of current (e.g., I_RMS(i)) measured by current sensor 106 (FIG. 3) by the resistance, ESR. The amount of current, I_RMS(i), is measured by current sensor 106 during time step 0. Also during time step 0, an amount of delivered power of 495 W is coupled into the plasma used to process substrate S1. The amount 495 W is the difference between the amount of power, 500 W, of RF signal 302 and the amount of power loss, 5 W, at output O2. During time step 0, processor 120 determines the amount of correction offset for the next time step, 5W, to be equal to the amount of power loss, 5W, associated with output O2.

[0063] During time step 1, processor 120 calculates the sum of recipe setpoint 500 W and the next time step correction offset 5 W determined during time step 0, and controls RF generator 102 to generate RF signal 302 having the sum, 505 W. The amount 505 W is an example of the amount of power P_sp_gen(i+1) delivered by RF generator 102 at output O1 of RF generator 102. Additionally, during time step 1, processor 120 accesses from memory device 122 the amount of delivered power loss, 8 W, at output O2. The amount of delivered power loss, 8 W, is calculated by processor 120 by multiplying the resistance ESR by the square of the amount of current (e.g., I_RMS(i+1)) measured by current sensor 106 ( FIG. 3 ). The amount of current I_RMS(i+1) is measured by current sensor 106 during time step 1. Also during time step 1, a delivered power amount of 497 W is coupled into the plasma used to process substrate S1. The amount 497 W is the difference between the delivered power amount 505 W of RF signal 302 and the amount of power loss 8 W associated with output O2. During time step 1, processor 120 determines the amount of correction offset for the next time step, 8 W, to be equal to the amount of power loss 8 W associated with output O2.

[0064] During time step 2, processor 120 calculates the sum of the recipe setpoint 500 W and the next time step correction offset 8 W determined during time step 1 and controls RF generator 102 to generate RF signal 302 having the summed quantity 508 W. Time step 2 is the time step consecutive to time step 1. The quantity 508 W is an example of the amount of power P_sp_gen(i+2) delivered by RF generator 102. Additionally, during time step 2, processor 120 accesses from memory device 122 the amount of delivered power loss 9 W at output O2. The amount of delivered power loss 9 W at output O2 is calculated by processor 120 by multiplying the amount of current (e.g., I_RMS(i+2)) measured by current sensor 106 ( FIG. 3 ) by the resistance ESR. The quantity I_RMS(i+2) is stored in memory device 122 by processor 120. An amount of current I_RMS(i+2) is measured by current sensor 106 during time step 2. Also during time step 2, an amount of delivered power of 499 W is coupled into the plasma used to process substrate S1. The amount 499 W is the difference between the amount of delivered power 508 W of RF signal 302 and the amount of power loss 9 W associated with output O2. During time step 2, processor 120 determines an amount of correction offset for the next time step, 9 W, to be equal to the amount of power loss 9 W associated with output O2.

[0065] During time step 3, processor 120 calculates the sum of recipe setpoint 500 W and the next time step correction offset 9 W determined during time step 2, and controls RF generator 102 to generate RF signal 302 having the summed quantity 509 W. Time step 3 is the time step that follows or follows time step 2. The quantity 509 W is an example of the amount of power P_sp_gen(i+3) delivered by RF generator 102. Additionally, during time step 3, processor 120 accesses from memory device 122 the amount of delivered power lost at output O2, 10 W. The amount of delivered power lost at output O2, 10 W, is calculated by processor 120 by multiplying the amount of current (e.g., I_RMS(i+3)) measured by current sensor 106 ( FIG. 3 ) by the resistance ESR. The quantity 10 W is measured by current sensor 106 and provided to processor 120. An amount of current I_RMS(i+3) is measured by current sensor 106 during time step 3. Also during time step 3, an amount of delivered power of 499 W is coupled into the plasma used to process substrate S1. The amount 499 W is the difference between the amount of delivered power 509 W of RF signal 302 and the amount of power loss 10 W associated with output O2. During time step 3, processor 120 determines an amount of correction offset for the next time step, 10 W, to be equal to the amount of power loss 10 W associated with output O2.

[0066] During time step 4, processor 120 calculates the sum of the recipe setpoint 500 W and the next time step correction offset 10 W determined during time step 3, and controls RF generator 102 to generate RF signal 302 having the summed amount 510 W. Time step 4 is the time step that follows or follows time step 3. The amount 510 W is an example of the amount of power P_sp_gen(i+4) delivered by RF generator 102. Additionally, during time step 4, processor 120 accesses from memory device 122 the amount of delivered power loss at output O2, 10.5 W. The amount of delivered power loss at output O2, 10.5 W, is calculated by processor 120 by multiplying the resistance ESR by the square of the amount of current (e.g., I_RMS(i+4)) measured by current sensor 106 ( FIG. 3 ). The amount of current I_RMS(i+4) is measured by current sensor 106 during time step 4. Also during time step 4, a delivered power amount of 499.5 W is coupled into the plasma used to process substrate S1. The amount 499.5 W is the difference between the delivered power amount of 510 W of RF signal 302 and the amount of power loss associated with output O2, 10.5 W. During time step 4, processor 120 determines the amount of correction offset for the next time step, 10.5 W, to be equal to the amount of power loss associated with output O2, 10.5 W.

[0067] During time step 5, processor 120 calculates the sum of recipe setpoint 500 W and the next time step correction offset of 10.5 W determined during time step 4, and controls RF generator 102 to generate RF signal 302 having the summed amount of 510.5 W. Time step 5 is the time step that follows or follows time step 4. The amount of power delivered by RF generator 102, P_sp_gen(i+5), is an example of the amount of power P_sp_gen(i+5). Additionally, during time step 5, processor 120 accesses from memory device 122 the amount of delivered power loss, 10.6 W, associated with output O2. The amount of delivered power loss, 10.6 W, at output O2 is calculated by processor 120 by multiplying the square of the amount of current, I_RMS(i+5), measured by current sensor 106 (FIG. 3), by the resistance, ESR. An amount of current (e.g., I_RMS(i+5)) is measured by current sensor 106 during time step 5. Also during time step 5, an amount of delivered power of 499.9 W is coupled into the plasma used to process substrate S1. The amount of 499.9 W is the difference between the amount of delivered power 510.5 W of RF signal 302 and the amount of power loss 10.6 W associated with output O2. During time step 5, processor 120 determines the amount of correction offset for the next time step, 10.6 W, to be equal to the amount of power loss 10.6 W associated with output O2.

[0068] During time step 6, processor 120 calculates the sum of recipe setpoint 500 W and the next time step correction offset of 10.6 W determined during time step 5, and controls RF generator 102 to generate RF signal 302 having the summed amount of 510.6 W. Time step 6 is the time step that follows or follows time step 5. The amount of power delivered by RF generator 102, P_sp_gen(i+6), is an example of the amount of power P_sp_gen(i+6). Additionally, during time step 6, processor 120 accesses from memory device 122 the amount of delivered power loss at output O2, 10.6 W. The amount of delivered power loss at output O2, 10.6 W, is calculated by processor 120 by multiplying the square of the amount of current (e.g., I_RMS(i+6)) measured by current sensor 106 (FIG. 3) by the resistance ESR. An amount of current I_RMS(i_6) is measured by current sensor 106 during time step 6. The amount of current I_RMS(i+6) is stored in memory device 122 by processor 120 and accessed (e.g., read or retrieved) from memory device 122 by processor 120. Also during time step 6, an amount of delivered power of 500 W is coupled into the plasma used to process substrate S1. The amount 500 W is the difference between the amount of delivered power 510.6 W of RF signal 302 and the amount of power loss 10.6 W associated with output O2. During time step 6, processor 120 determines an amount of correction offset for the next time step, 10.6 W, to be equal to the amount of power loss 10.6 W associated with output O2.

[0069] In this manner, processor 120 continues to control the amount of power delivered by RF generator 102 at output O1 of RF generator 102 based on the amount of power loss measured at output O2 of impedance match circuit 104 until the amount of power loss is compensated for. The amount of power loss is compensated for when the amount of power loss stabilizes. For example, between time steps 5 and 6, processor 120 determines that the same amount of power loss, 10.6 W, has occurred based on the amount of current delivered at output O2 measured by current sensor 106 and the resistance ESR associated with output O2. Upon determining that the amount of power loss is stable, processor 120 controls RF generator 102 to not change the amount of power delivered by RF generator 102 at output O1 of RF generator 102. For example, after time step 6, processor 120 controls RF generator 102 to deliver an amount of power of 510.6 W at output O1 of RF generator 102, and does not change the amount 510.6 W. By way of further example, after time step 6, current sensor 106 is disconnected from output O2 of impedance matching circuit 104. It is not necessary to continue measuring the current at output O2 to determine the amount of delivered power loss at output O2.

[0070] In one embodiment, instead of determining the same amount of power loss for two consecutive time steps, processor 120 determines that the amount of power loss during two consecutive time steps is stable by determining that the amounts of power loss during the latter of the two time steps are within a predetermined range of each other. For example, assume that the amount of power loss during time step 5 is 10.61 W instead of 10.6 W, and if the amount of power loss during time step 6 is 10.6 W, processor 120 determines that the amounts 10.6 W and 10.61 W are within a predetermined range of 0.1 W or 0.2 W from each other, thereby determining that the amount of power loss 10.6 W is stable during time step 6. As another example, suppose the amount of power loss during time step 5 is 10.62 W instead of 10.6 W, and the amount of power loss during time step 6 is 10.6 W, processor 120 determines that the amounts 10.6 W and 10.62 W are within a predetermined range of 0.2 W or 0.3 W from each other, and determines that the amount of power loss during time step 6, 10.6 W, is stable.

[0071] In one embodiment, the iterations of the method of measuring the current at the output O2 of the impedance matching circuit 104, determining the amount of power loss at the output O2 of the impedance matching circuit 104 from the current measurement and the resistance ESR, and determining the amount of power delivered by the RF generator 102 from the amount of power loss and the recipe setpoint of the RF generator 102 are performed at a rate ranging from 50 Hertz (Hz) to 1 kHz. For example, the measurement of the amount of current (e.g., I_RMS(i)) at the output O2, the determination of the quantity P_loss(i) from the measurement I_RMS(i) and the resistance ESR, and the determination of the quantity P_sp_gen(i+1) from the recipe setpoint P_sp_rec and the quantity P_loss(i) are repeated iteratively 50 times per second, 1000 times per second, or between 50 times per second and 1000 times per second. As another example, 50 or 1000 time steps (example time steps are provided above with respect to table 400) occur per second. During each time step, a quantity of current (such as I_RMS(i)) is measured at output O2, a quantity P_loss(i) is determined from the measurement I_RMS(i) and the resistance ESR, and a quantity P_sp_gen(i+1) is determined from the recipe setpoint P_sp_rec and the quantity P_loss(i).

[0072] In one embodiment, the amount 510W is an example of an amount of power P_sp_gen(i) delivered by the RF generator 102, the amount 510.5W is an example of an amount of power P_sp_gen(i+1) delivered by the RF generator 102, and the amount 510.6W is an example of an amount of power P_sp_gen(i+2) delivered by the RF generator 102.

[0073] FIG. 5 illustrates one embodiment of a graph 500 to illustrate how the power P_sp_gen delivered by the RF generator 102 (FIG. 3) at output O1 varies with the loss P_loss of the power delivered at output O2 of the impedance matching circuit 104 (FIG. 3). Note that the "sp" in the term "P_sp_gen" represents a setpoint, and the "gen" in the term "P_sp_gen" represents the RF generator 102. Graph 500 plots the power P_sp_gen delivered by the RF generator 102 versus time t. Graph 500 includes a plot 502, another plot 504, and yet another plot 506. Plot 502 illustrates the delivered power P_sp_ge at output O1 of the RF generator 102. Additionally, plot 504 illustrates the loss P_loss of the power delivered at output O2 of the impedance matching circuit 104, and plot 506 illustrates a recipe set point P_sp_rec, which is a constant amount.

[0074] As shown in graph 500, as the amount of loss of delivered power P_loss (P_loss(i), P_loss(i+1), P_loss(i+2), etc.) increases with time t, the amount of delivered power P_sp_gen (e.g., P_sp_gen(i), P_sp_gen(i+1), P_sp_gen(i+2), P_sp_gen(i+3), P_sp_gen(i+4), P_sp_gen(i+5), P_sp_gen(i+6), etc.) increases with time t. By accounting for the loss of delivered power P_loss, uniformity in the processing of substrate S1 ( FIG. 4 ) or another substrate is achieved with time t. Note that the difference between the delivered power P_sp_gen and the recipe set point P_sp_rec is referred to herein as the set point offset.

[0075] 6 illustrates an embodiment of a system 600 for illustrating an application of the method for compensating for loss of transmitted power. The system 600 includes a comparator 602, a controller 604, a summer 606, an RF generator 102, an impedance matching circuit 104, a plasma chamber 108, a current sensor 106, a delay circuit 608, a filter 610, a controller 611, and a comparator 612.

[0076] Examples of the controller 604 include the processor 120 (FIG. 3), an ASIC, a PLD, a CPU, a microprocessor, and a microcontroller. Another example of the controller 604 includes a combination of the processor 120 and the processor of the RF generator 102. Examples of the comparer 602 or the comparator 612 include a controller, a processor, a PLD, a CPU, a microprocessor, and a microcontroller. Each of the summer 606, the delay circuit 608, and the filter 610 may be implemented using a controller, a processor, a PLD, a CPU, a microprocessor, and a microcontroller. An example of the filter 610 includes a low-pass filter that filters out high frequencies from the current I_RMS.

[0077] The comparator 602 is connected to a controller 604, and the controller 604 is connected to a summer 606. The summer 606 is connected to the RF generator 102 via a connecting cable. The delay circuit 608 is connected to the current center 106 via a connecting cable. The delay circuit 608 is connected to a filter 610, and the filter 610 is connected to a controller 611. The controller 611 is connected to a comparator 612, and the comparator 612 is connected to the comparator 602.

[0078] The power sensor 106 measures the amount of current I_RMS (I_RMS(i), I_RMS(i+1), I_RMS(i+2), I_RMS(i+3), I_RMS(i+4), I_RMS(i+5), or I_RMS(i+6), etc.) measured during processing of a substrate or the amount of current Irms measured during plasma-free testing and provides it to the delay circuit 608. The delay circuit 608 accounts for (e.g., reduces or eliminates) a time delay associated with the current I_RMS measured during processing of a substrate or associated with the current Irms measured during plasma-free testing. For example, the delay circuit 608 reduces or eliminates the time delay in receiving the amount of current I_RMS from the current sensor 106 by the processor 120, the time delay in processing the current measurement I_RMS and the resistance ESR by the processor 120 to determine the power loss P_loss at the output O2 of the impedance matching circuit 102, and the time delay in determining the amount of delivered power P_sp_gen from the power loss P_loss and the recipe set point P_sp_rec by the processor 120. As another example, the delay circuit 608 reduces or eliminates the time delay in receiving the amount of current Irms from the current sensor 106 by the processor 120. The delay circuit 608 reduces or eliminates the time delay associated with the current I_RMS and the time delay associated with the current Irms and provides the current measurement I_RMS or the current measurement Irms (e.g., amount) to the filter 610.

[0079] The filter 610 removes (e.g., filters) high-frequency components of the amount of current I_RMS or the amount of current Irms measured by the current sensor 106. The controller 611 determines the value of the resistor ESR from the relationship between the amount of current Irms measured by the current sensor 106 and the amount of delivered power P_del, as shown in graph 200 (FIG. 2). The controller 611 also determines the amount of power loss P_loss from the resistor ESR and the square of the current I_RMS, and provides the amount of delivered power loss P_loss to the comparator 612.

[0080] Comparator 612 compares the amount of power delivered to input I2 of impedance match circuit 104 with the amount of delivered power loss, P_loss, to determine the amount of delivered power, P_coupled, coupled to the plasma in plasma chamber 108. The power delivered to input I2 is designated as P_del. Comparator 612 provides the amount of delivered power, P_coupled, coupled to the plasma to comparator 602.

[0081] Additionally, comparator 602 compares the amount of power P_coupled coupled to the plasma in plasma chamber 108 with recipe setpoint P_sp_rec to determine the amount of delivered power loss P_loss at output O2 of impedance match circuit 104. Controller 604 receives the amount of delivered power loss P_loss at output O2 of impedance match circuit 104 from comparator 602 and provides the loss amount to summer 606. Summer 606 adds the amount of delivered power loss P_loss at output O2 of impedance match circuit 104 to recipe setpoint P_sp_rec to generate a total or aggregate setpoint, which is provided as an input to RF generator 102 via a connecting cable. RF generator 102 is operated to generate and provide a total delivered power setpoint at output O1 of RF generator 102.

[0082] In one embodiment, delay circuit 608, filter 610, controller 611, comparator 612, comparator 602, controller 604, and adder 606 are implemented within processor 120. For example, delay circuit 608, filter 610, controller 611, comparator 612, comparator 602, controller 604, and adder 606 are part of processor 120.

[0083] In one embodiment, filter 610 is optional and may not be used in system 600. For example, delay circuit 608 is not connected to filter 610 but is connected to controller 611.

[0084] In one embodiment, the functions described herein performed by delay circuit 608, filter 610, controller 611, comparator 612, comparator 602, controller 604, and summer 606 are performed by one or more processors. For example, the functions described herein performed by delay circuit 608, filter 610, and controller 611 are performed by one processor, and the functions described herein performed by comparator 612, comparator 602, controller 604, and summer 606 are performed by another processor (e.g., processor 120).

[0085] 7 illustrates an embodiment of a system 700 for illustrating that the delivered power P_sp_gen determined by applying the method described with reference to FIG. 3 or 4 is maintained for processing another substrate S2 after processing substrate S1. System 700 includes the same components as system 300, except that system 700 does not include current sensor 106. Current sensor 106 is not connected to output O2 of impedance matching circuit 104. For example, current sensor 106 is decoupled from output O2 of impedance matching circuit 104. Furthermore, substrate S1, which is disposed on the upper surface of chuck 112, is removed from plasma chamber 108, and after substrate S1 is removed, substrate S2 is placed on the upper surface for processing.

[0086] Once processor 120 determines the amount of transmit power (e.g., P_sp_gen(i+1), P_sp_gen(i+10), or 510.6 W ( FIG. 4 )) supplied by RF generator 102 such that the amount of power loss P_loss is within a predetermined range over multiple time steps (e.g., multiple periods), processor 120 does not change the amount of transmit power supplied by RF generator 102. For example, processor 120 provides a command signal having an amount of 510.6 W to RF generator 102 to generate RF signal 302 having a transmit power amount of 510.6 W during each time step after time step 6 in FIG. 4 . Upon receiving the command signal having the amount 510.6 W, RF generator 102 generates RF signal 302 having the amount 510.6 W and provides RF signal 302 to impedance matching circuit 104 via output O1 and input I2.

[0087] Upon receiving the RF signal 302, the impedance match circuit 104 matches the impedance of the load connected to the output O2 to the impedance of the source connected to the input I2 and outputs a modulated RF signal 304. One or more process gases are supplied to the plasma chamber 108, and the modulated RF signal 304 is supplied to the lower electrode of the chuck 112, and a plasma is ignited or sustained in the plasma chamber 108. The plasma in the plasma chamber 108 processes a substrate S2 disposed in the plasma chamber 108.

[0088] 3 and 4 of measuring the current I_RMS at the output O2 of the impedance matching circuit, determining the power loss P_loss at the output O2 from the current I_RMS and the resistance ESR, and determining the delivery power P_sp_gen to be applied to the RF generator 104 based on the power loss P_loss and the recipe set point P_sp_rec is repeated for substrate S2 at one or more time steps after processing of substrate S1. The delivery power P_sp_gen determined for substrate S2 is then applied to substrate S2 at a further time step.

[0089] In one embodiment, the method described herein for compensating for RF power losses is applied to other types of semiconductor processing tools, such as an inductively coupled plasma (IC) tool, an electron cyclotron resonance (ECR) tool, or a plasma-enhanced chemical vapor deposition (PECVD) tool. For example, instead of the CCP plasma chamber 108, an ICP plasma chamber, an ECR plasma chamber, or a PECVD plasma chamber is used. For example, the RF transmission line 118 is connected to the lower electrode of the ICP plasma chamber. In this example, the transformer-coupled plasma (TCP) coil of the ICP plasma chamber is connected to ground potential or is also connected to one or more RF generators through an impedance matching circuit. As another example, the RF transmission line 118 is connected to the pedestal of the PECVD plasma chamber. As yet another example, the RF transmission line 118 is connected to the TCP coil of the ICP plasma chamber. In this example, the lower electrode of the ICP plasma chamber is also connected to ground potential or is also connected to one or more RF generators through an impedance matching circuit. Note that the plasma chamber 108 is a type of semiconductor processing tool.

[0090] The embodiments described herein may be practiced with various computer system configurations, including handheld hardware units, microprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, etc. The embodiments described herein may also be practiced in distributed computing environments where tasks are performed by remote processing hardware units that are linked through a computer network.

[0091] In some embodiments, the controller is part of a system, which may be part of the examples described above. The system includes semiconductor processing equipment, such as one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (e.g., wafer pedestal, gas flow system, etc.). The system is integrated with electronics for controlling the operation of the system before, during, and after processing of semiconductor wafers or substrates. The electronics may be referred to as a "controller" and may control various components or subcomponents of the system. The controller is programmed to control any of the processes disclosed herein, such as supply of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, RF generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid supply settings, position and motion settings, and wafer movement in and out of the tool and other transfer tools and / or load locks connected or coupled to the system, depending on the processing requirements and / or type of system.

[0092] Generally, in various embodiments, a controller is defined as an electronic device having various integrated circuits, logic, memory, and / or software that receives instructions, issues instructions, controls operations, enables cleaning operations, enables endpoint measurements, etc. Integrated circuits include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as ASICs, PLDs, one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions are instructions communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing processes on or for semiconductor wafers. The operational parameters, in some embodiments, are part of a recipe defined by a process engineer to accomplish one or more process steps during processing of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0093] In some embodiments, the controller is part of or connected to a computer that is integrated with, connected to, or otherwise networked with the system, or a combination thereof. For example, the controller may be in the "cloud" or may be all or part of a fab host computer system that enables remote access for wafer processing. The controller may enable remote access to the system to change parameters of a current process, set process steps according to a current process, or initiate a new process, monitor the current progress of a manufacturing operation, examine the history of past manufacturing operations, or examine trends or performance indicators from multiple manufacturing operations.

[0094] In some embodiments, a remote computer (e.g., a server) provides process recipes to the system via a computer network (including a local network or the Internet). The remote computer includes a user interface that allows for entry or programming of parameters and / or settings, which are communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of settings for processing wafers. It should be understood that the settings are specific to the type of process to be performed on the wafer and the type of tool the controller interfaces with or controls. Thus, as described above, the controller is distributed, such as by having one or more separate controllers that are networked and operate toward a common purpose (such as performing processes described herein). One example of a distributed controller for such purposes includes one or more integrated circuits on the chamber that communicate with one or more remotely located integrated circuits (e.g., located at the platform level or remotely as part of a remote computer) that cooperate to control processing in the chamber.

[0095] In various embodiments, the plasma system includes, but is not limited to, a plasma etch chamber, a deposition chamber, a spin rinse chamber, a metal plating chamber, a cleaning chamber, a bevel edge etch chamber, a physical vapor deposition (PVD) chamber, a chemical vapor deposition (CVD) chamber, an atomic layer deposition (ALD) chamber, an atomic layer etch (ALE) chamber, an ion implantation chamber, a track chamber, and any other semiconductor processing system associated with or utilized in the fabrication and / or manufacturing of semiconductor wafers.

[0096] Also, while the operations described above are described with respect to a parallel plate plasma chamber, in some embodiments, the operations described above apply to other types of plasma chambers, such as plasma chambers with transformer coupled plasma (TCP) reactors, dielectric tools, electron cyclotron resonance (ECR) reactors, etc. An example of a TCP reactor includes an inductively coupled plasma (ICP) reactor. Another example of a TCP reactor includes a conductor tool. At times, the terms reactor and plasma chamber are used interchangeably herein.

[0097] As described above, depending on the processing operations being performed by the tool, the controller communicates with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used in material transport to carry containers of wafers to or from tool locations and / or load ports within a semiconductor fabrication factory.

[0098] With the above embodiments in mind, it should be understood that some of the embodiments employ various computer-implemented operations involving data stored in computer systems. The computer-implemented operations are operations involving physical quantities.

[0099] Some embodiments further relate to hardware units or apparatus for performing these operations, where the apparatus is specifically configured for a special purpose computer. When defined as a special purpose computer, the computer can operate for a specific purpose while performing other processes, program execution, or routines not included in the specific purpose.

[0100] In some embodiments, the operations described herein are processed on a computer selectively activated or configured by one or more computer programs stored in computer memory or obtained over a computer network. When data is obtained over a computer network, the data may be processed by other computers on the computer network (e.g., a cloud of computing resources).

[0101] One or more embodiments described herein may be fabricated as computer-readable code on a non-transitory computer-readable medium. The non-transitory computer-readable medium is any data storage hardware unit (e.g., a memory device) that stores data, which is then read by a computer system. Examples of non-transitory computer-readable media include hard drives, network-attached storage (NAS), ROM, RAM, compact disc-ROMs (CD-ROMs), CD-recordables (CD-Rs), CD-rewritables (CD-RWs), magnetic tapes, and other optical and non-optical data storage hardware units. In some embodiments, the non-transitory computer-readable medium includes a tangible computer-readable medium distributed over network-connected computer systems such that the computer-readable code is stored and executed in a distributed manner.

[0102] Although some of the method actions described above are presented in a particular order, it should be understood that in various embodiments, other housekeeping operations are performed between method actions, or method actions are performed at slightly different times, or are distributed across a system that allows method actions to occur at various intervals, or are arranged to be performed in an order different from that described above.

[0103] Furthermore, it should be noted that in one embodiment, one or more features of any embodiment described herein may be combined with one or more features of any other embodiment without departing from the scope described in the various embodiments described in this disclosure.

[0104] Although the present embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be made within the scope of the appended claims. The present embodiments are therefore to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein, but may vary within the scope of the appended claims and their equivalents. [Application Example 1] A method for compensating for radio frequency (RF) power loss, comprising: obtaining a plurality of measurements of a plurality of parameters associated with components of the plasma system; determining a resistance associated with the component of the plasma system from the plurality of measurements of the plurality of parameters; obtaining a value of a parameter of the plurality of parameters associated with the component of the plasma system; determining an amount of the RF power loss associated with the component of the plasma system from the resistance and the value of the one of the plurality of parameters; adjusting an operating set point of the RF generator based on the amount of RF power loss; repeating the steps of determining one or more additional values ​​for the one of the plurality of parameters, determining one or more additional amounts of the RF power loss, and modifying the set point of operation of the RF generator until the amount of adjustment applied to the set point compensates for the RF power loss; A method comprising: [Application Example 2] The method described in Application Example 1, wherein when multiple RF power loss amounts fall within predetermined ranges, the amount of adjustment applied to the setpoint compensates for the RF power loss. [Application Example 3] The method described in Application Example 1, wherein the acquisition of the multiple measurements and the determination of the resistance are performed during or after a plasma-free test. [Application Example 4] The method described in Application Example 1, wherein the obtaining of the value, the determination of the amount of RF power loss, the adjustment of the set point, and the repetition are performed during processing of a substrate. [Application Example 5] The method described in Application Example 1, wherein the component of the plasma system is an impedance matching circuit. [Application Example 6] A method as described in Application Example 1, wherein determining the amount of RF power loss comprises multiplying the resistance by the square of the value of one of the plurality of parameters. [Example 7] The method of Example 1, wherein adjusting the set point of operation of the RF generator is performed to control the RF generator to operate at a second set point; The repetition obtaining a second value of the one of the plurality of parameters associated with the component of the plasma system; determining a second RF power loss amount from the resistance and the second value of the one of the plurality of parameters; adjusting the set point of operation of the RF generator based on the second amount of RF power loss, the method being performed to control the RF generator to operate at a third set point. [Application Example 8] The method described in Application Example 1, wherein adjusting the set point includes adding the amount of RF power loss to the set point. [Application Example 9] A controller for compensating for radio frequency (RF) power loss, comprising: 1. A processor, comprising: obtaining a plurality of measurements of a plurality of parameters associated with components of the plasma system; determining a resistance associated with the component of the plasma system from the plurality of measurements of the plurality of parameters; obtaining a value of a parameter of the plurality of parameters associated with the component of the plasma system; determining an amount of the RF power loss associated with the component of the plasma system from the resistance and the value of the one of the plurality of parameters; adjusting an operating set point of the RF generator based on the amount of RF power loss; a processor configured to repeat determining one or more additional values ​​for the one parameter of the plurality of parameters, determining one or more additional amounts of the RF power loss, and adjusting the set point of operation of the RF generator until the amount of adjustment applied to the set point compensates for the RF power loss; and a memory device coupled to the processor for storing the plurality of measurements of the plurality of parameters; A controller comprising: [Application Example 10] The controller according to Application Example 9, wherein the processor determines that the amount of adjustment being applied to the setpoint compensates for the RF power loss when multiple RF power loss amounts fall within predetermined ranges. [Application Example 11] The controller according to Application Example 9, wherein the processor acquires the plurality of measurements and determines the resistance during or after a plasma-free test. [Application Example 12] A controller as described in Application Example 9, wherein the processor, during processing of a substrate, obtains the value of one of the plurality of parameters, determines the amount of RF power loss, adjusts the set point, and repeats obtaining the one or more further values, determining the one or more further amounts of RF power loss, and adjusting the set point for operation of the RF generator. [Application Example 13] The controller according to Application Example 9, wherein the component of the plasma system is an impedance matching circuit. [Application Example 14] A controller as described in Application Example 9, wherein, to determine the amount of RF power loss, the processor is configured to multiply the resistance by the square of the value of the one of the parameters. [Application Example 15] The controller of Application Example 9, wherein the processor is configured to adjust the set point of operation of the RF generator to control the RF generator to operate at a second set point; To iterate between obtaining the one or more additional values, determining the one or more additional amounts of RF power dissipation, and adjusting the set point of operation of the RF generator, the controller: obtaining a second value of the one of the plurality of parameters associated with the component of the plasma system; determining a second RF power loss amount from the resistance and the second value of the one of the plurality of parameters; configured to adjust the set point of operation of the RF generator based on the second amount of RF power loss; The processor is configured to adjust the set point of operation of the RF generator based on the second amount of RF power loss to control the RF generator to operate at a third set point. [Application Example 16] The controller according to Application Example 9, wherein the processor is configured to sum the amount of RF power loss and the set point to adjust the set point. [Application Example 17] A plasma system for compensating for radio frequency (RF) power loss, comprising: a radio frequency (RF) generator configured to generate an RF signal; an impedance matching circuit connected to the RF generator to receive the RF signal; a computer connected to the RF generator; Equipped with The computer obtaining a plurality of measurements of a plurality of parameters associated with components of the plasma system; determining a resistance associated with the component of the plasma system from the plurality of measurements of the plurality of parameters; obtaining a value of a parameter of the plurality of parameters associated with the component of the plasma system; determining an amount of the RF power loss associated with the component of the plasma system from the resistance and the value of the one of the plurality of parameters; adjusting an operating set point of the RF generator based on the amount of RF power loss; and repeating: determining one or more additional values ​​for the one parameter of the plurality of parameters; determining one or more additional amounts of the RF power loss; and adjusting the set point of operation of the RF generator until the amount of adjustment applied to the set point compensates for the RF power loss. [Application Example 18] A plasma system according to Application Example 17, wherein the computer determines that the amount of adjustment applied to the set point compensates for the RF power loss when multiple RF power loss amounts each fall within a predetermined range. [Application Example 19] In the plasma system according to Application Example 17, the computer adjusts the set point of operation of the RF generator to control the RF generator to operate at a second set point; To iterate between obtaining the one or more additional values, determining the one or more additional amounts of RF power dissipation, and adjusting the set point of operation of the RF generator, the computer: obtaining a second value of the one of the plurality of parameters associated with the component of the plasma system; determining a second RF power loss amount from the resistance and the second value of the one of the plurality of parameters; configured to adjust the set point of operation of the RF generator based on the second amount of RF power loss; the computer is configured to adjust the setpoint of operation of the RF generator based on the second amount of RF power loss to control the RF generator to operate at a third setpoint. [Application Example 20] A plasma system as described in Application Example 17, wherein the computer determines that the amount of adjustment applied to the set point compensates for the RF power loss when multiple RF power loss amounts fall within a predetermined range from each other.

Claims

1. A method for compensating for radio frequency (RF) power losses, comprising: Obtaining a first value of a parameter associated with a component of the plasma system; determining a first RF power loss amount associated with the component of the plasma system from the resistance and the one value of the parameter; adjusting an operating setpoint of the RF generator based on the first amount of RF power loss to operate the RF generator at a second setpoint; obtaining a second value of the parameter associated with the component of the plasma system; determining a second RF power loss amount from the resistance and the second value of the parameter; adjusting the set point of operation of the RF generator based on the second amount of RF power loss to operate the RF generator at a third set point; The method, wherein the set point of operation is adjusted based on the first amount of RF power loss and the second amount of RF power loss to compensate for RF power loss.

2. A method according to claim 1, the parameter is a current, the component includes an impedance matching circuit, obtaining the first value of the parameter includes obtaining the first value of the current measured between the impedance matching circuit of the plasma system and a chuck of a plasma chamber, and obtaining the second value of the parameter includes obtaining the second value of the current measured between the impedance matching circuit and the chuck.

3. The method according to claim 2, The method of claim 1, wherein the current is a root mean square current, the first value of the current is measured at an output of the impedance matching circuit, and the second value of the current is measured at the output of the impedance matching circuit.

4. The method according to claim 2, the current is a root mean square current, the first value of the current is measured at an RF transmission line connected between the impedance matching circuit and the chuck, and the second value of the current is measured at the RF transmission line.

5. The method according to claim 2, The method of claim 1, wherein the current is a root mean square current, the first value of the current is measured at an input of the chuck, and the second value of the current is measured at the input of the chuck.

6. The method of claim 1, further comprising: calculating the square of the first value of the parameter to determine the first RF power loss amount includes multiplying the resistance by the square of the first value of the parameter; calculating the square of the second value of the parameter, and determining the second amount of RF power loss includes multiplying the resistance by the square of the second value of the parameter.

7. The method of claim 1, adjusting the set point of operation of the RF generator based on the first amount of RF power loss includes adding the first amount of RF power loss to the set point of operation to determine the second set point, and adjusting the set point of operation of the RF generator based on the second amount of RF power loss includes adding the second amount of RF power loss to the set point of operation to determine the third set point.

8. A controller for compensating for radio frequency (RF) power losses, comprising:

1. A processor, comprising: Obtaining a first value of a parameter associated with a component of the plasma system; determining a first RF power loss amount associated with the component of the plasma system from the resistance and the first value of the parameter; adjusting an operating setpoint of the RF generator based on the first amount of RF power loss to operate the RF generator at a second setpoint; obtaining a second value of the parameter associated with the component of the plasma system; determining a second RF power loss amount from the resistance and the second value of the parameter; configured to adjust the set point of operation of the RF generator based on the second amount of RF power loss to operate the RF generator at a third set point; a processor, wherein the set point of operation is adjusted based on the first amount of RF power loss and the second amount of RF power loss to compensate for RF power loss; a memory device coupled to the processor; A controller comprising:

9. The controller of claim 8, A controller, wherein the parameter is a current, the component includes an impedance matching circuit, and to obtain the first value of the parameter, the processor is configured to obtain the first value of the current measured between the impedance matching circuit of the plasma system and a chuck of a plasma chamber, and to obtain the second value of the parameter, the processor is configured to obtain the second value of the current measured between the impedance matching circuit and the chuck.

10. The controller of claim 9, The current is a root mean square current, the first value of the current is measured at an output of the impedance matching circuit, and the second value of the current is measured at the output of the impedance matching circuit.

11. The controller of claim 9, the current is a root mean square current, the first value of the current is measured at an RF transmission line connected between the impedance matching circuit and the chuck, and the second value of the current is measured at the RF transmission line.

12. The controller of claim 9, The current is a root mean square current, the first value of the current is measured at an input of the chuck, and the second value of the current is measured at the input of the chuck.

13. The controller of claim 8, The processor: configured to calculate the square of the first value of the parameter and multiply the resistance by the square of the first value of the parameter to determine the first amount of RF power loss; a controller configured to calculate the square of the second value of the parameter and to multiply the resistance by the square of the second value of the parameter to determine the second amount of RF power loss.

14. The controller of claim 8, the processor is configured to add the first amount of RF power loss to the setpoint of operation to adjust the setpoint of operation of the RF generator based on the first amount of RF power loss, and the processor is configured to add the second amount of RF power loss to the setpoint of operation to adjust the setpoint of operation of the RF generator based on the second amount of RF power loss.

15. A plasma system for compensating for radio frequency (RF) power losses, comprising: a radio frequency (RF) generator configured to generate an RF signal; an impedance matching circuit connected to the RF generator to receive the RF signal; a computer connected to the RF generator; The computer obtaining a first value of a parameter associated with a component of the plasma system; determining a first RF power loss amount associated with the component of the plasma system from the resistance and the first value of the parameter; adjusting a set point of operation of the RF generator based on the first amount of RF power loss to operate the RF generator at a second set point; obtaining a second value of the parameter associated with the component of the plasma system; determining a second RF power loss amount from the resistance and the second value of the parameter; configured to adjust the set point of operation of the RF generator based on the second amount of RF power loss to operate the RF generator at a third set point; The set point of operation is adjusted based on the first amount of RF power loss and the second amount of RF power loss to compensate for RF power loss.

16. The plasma system of claim 15, further comprising: a plasma chamber having a chuck; the parameter is a current, the component includes the impedance matching circuit, and to obtain the first value of the parameter, the computer is configured to obtain the first value of the current measured between the impedance matching circuit and the chuck, and to obtain the second value of the parameter, the computer is configured to obtain the second value of the current measured between the impedance matching circuit and the chuck.

17. The plasma system of claim 16, the impedance matching circuit has an output, the current is a root mean square current, the first value of the current is measured at the output of the impedance matching circuit, and the second value of the current is measured at the output of the impedance matching circuit.

18. The plasma system of claim 16, 10. A plasma system comprising: a chuck connected to the impedance match circuit via an RF transmission line; the current is a root mean square current; the first value of the current is measured at the RF transmission line; and the second value of the current is measured at the RF transmission line.

19. The plasma system of claim 16, the chuck has an input connected to the impedance match circuit, the current is a root mean square current, the first value of the current is measured at the input of the chuck, and the second value of the current is measured at the input of the chuck.

20. The plasma system of claim 15, The computer configured to calculate the square of the first value of the parameter and multiply the resistance by the square of the first value of the parameter to determine the first amount of RF power loss; a plasma system configured to calculate the square of the second value of the parameter and multiply the resistance by the square of the second value of the parameter to determine the second RF power loss amount.

21. The plasma system of claim 15, to adjust the set point of operation of the RF generator based on the first amount of RF power loss, the computer is configured to add the first amount of RF power loss to the set point of operation, and to adjust the set point of operation of the RF generator based on the second amount of RF power loss, the computer is configured to add the second amount of RF power loss to the set point of operation.

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