Hybrid frequency plasma source

Abstract

The plasma system includes a first matchless plasma source (MPS) generating a first sinusoidal waveform having a first frequency. The plasma system includes a first filter coupled to the first MPS to filter a second frequency. The plasma system further includes a first capacitive circuit coupled to the first filter to balance between a reactance of the first filter and a radio frequency (RF) coil and provide a first RF signal to the point. The plasma system includes a second MPS generating a second sinusoidal waveform having a second frequency. The plasma system includes a second filter coupled to the second MPS to filter the first frequency. The plasma system includes a second capacitive circuit coupled to the second filter to balance a reactance of the second filter and a reactance of the RF coil and further provide a second RF signal to the point.

Description

Technical Field

[0001] This embodiment relates to a hybrid frequency plasma source.

Background Art

[0002] Plasma systems are used to perform various operations on wafers. A plasma system includes a radio frequency (RF) generator, an RF matcher, and a plasma chamber. The RF generator is coupled to the RF matcher via an RF cable, and the RF matcher is coupled to the plasma chamber. RF power is provided to the plasma chamber in which the wafers are processed via the RF cable and the RF matcher. Also, one or more gases are supplied to the plasma chamber, and when the RF power is received, plasma is generated or maintained in the plasma chamber. When RF power is provided, the plasma may not be struck in the plasma chamber, or an arc discharge may occur in the plasma chamber.

[0003] The embodiments described in this disclosure arise from such a background.

Summary of the Invention

[0004] Embodiments of the present disclosure provide a system, an apparatus, a method, and a computer program for providing a hybrid frequency plasma source. It should be understood that this embodiment can be implemented in a number of ways, such as, for example, a process, or an apparatus, or a system, or hardware, or a method, or a computer-readable medium. Some embodiments will be described below.

[0005] Each inductively coupled plasma (ICP) coil in the plasma chamber is driven at a single RF frequency by a single radio frequency (RF) generator at any given moment. The choice of RF frequency is limited by several factors. The coil voltage of the ICP coil increases with increasing RF frequency, which can cause arc discharge in the ICP coil or sputtering in the dielectric window of the plasma chamber. Arc discharge or sputtering is caused by ions accelerated by capacitively coupled RF power from the coil. On the other hand, at lower radio frequencies, the coupling effect is particularly small at lower plasma densities. Also, at lower voltages in the ICP coil, it is more difficult for the RF generator to chemically alter the neutral gas and strike the plasma.

[0006] In one embodiment, a dual-frequency ICP source operating at two radio frequencies is presented. For example, two independent RF sources (e.g., RF generators or matchless plasma sources (MPS)) tuned to two widely separated RF frequencies are used to simultaneously power an ICP coil with a single feed. For example, two MPS (e.g., a low-frequency MPS and a high-frequency MPS) are used to drive the same ICP coil. The two MPS operate at two far-off frequencies, a low frequency and a high frequency. As an example, the low frequency is in the range of 1.8 megahertz (MHz) to 2.2 MHz and the high frequency is in the range of 12.35 MHz to 13.65 MHz. As another example, the low frequency is in the range of 400 kilohertz (kHz) to 2 MHz and the high frequency is in the range of 12 MHz to 27 MHz. The corresponding output of each MPS is mounted to a filter circuit for isolation. Furthermore, each filter circuit is coupled to a corresponding capacitor to cancel out residual reactance from the ICP coil and filter circuit, so that low-frequency and high-frequency series resonances are presented to the low-frequency and high-frequency MPS, respectively. Each capacitor can be either a fixed-value capacitor or a variable-value capacitor. For example, the network between each MPS and the ICP coil includes fixed elements (e.g., fixed capacitors and fixed inductors) and does not include variable elements, thus eliminating the need for active control of the network during operation.

[0007] In one embodiment, a low-pass filter and a high-pass filter can be coupled to the outputs of the low-frequency MPS and the high-frequency MPS, respectively.

[0008] In one embodiment, a bandpass filter can be coupled to the output of either of the two MPS. For example, a series resonant circuit including a series circuit of a capacitor and an inductor can be used as a bandpass filter to provide appropriate isolation from low or high frequencies.

[0009] In one embodiment, a first bandpass filter is coupled to the output of a low-frequency MPS, and a second bandpass filter is coupled to the output of a high-frequency MPS.

[0010] In one embodiment, two 50Ω RF generators operate at different RF frequencies and energize the same ICP coil. The two RF generators employed are capable of outputting RF tuned to a low-frequency band of 400kHz to 2MHz and a high-frequency band of 12MHz to 27MHz, respectively. These two RF generators provide input to a dual-frequency impedance matching network, which converts the impedance of the ICP coil at its output port to 50 ohms and presents it to the two RF generators.

[0011] In one embodiment, a dual-frequency impedance matching network includes one or more isolation filter circuits. The dual-frequency impedance matching network includes two subnetworks, one for low-frequency transmission and the other for high-frequency transmission. The isolation filter circuits can be placed on either the input or output side of each of the two subnetworks, or on both the input and output sides. Each of the two subnetworks converts the corresponding low-frequency and high-frequency load impedances to 50Ω. For example, an isolation filter circuit can be placed on the output side to minimize the change observed in the other subnetwork when a circuit element on one subnetwork is changed. Examples of subnetworks include L-type networks and T-type networks.

[0012] In one embodiment, the same ICP coil is energized using an MPS and a 50-ohm RF generator. The MPS operates at a different frequency than the 50-ohm RF generator.

[0013] In one embodiment, since the low frequency and high frequency are independent of each other, various pulse operations can be achieved. For example, one frequency can output a pulse, while the other outputs a continuous wave (CW). In another example, both the low frequency and high frequency can output pulses with different pulse output frequencies and duty cycles.

[0014] In one embodiment, a current-dividing circuit is provided for use with a dual-coil plasma system (e.g., a plasma system having two transformer-coupled plasma (TCP) coils). The current-dividing circuit is added to the output of a first MPS of one frequency (e.g., low frequency or high frequency), and the same MPS drives both TCP coils. In this embodiment, a second MPS can be added to the first of the TCP coils. Additional filters can be added so that the frequency of the second MPS is blocked from the second of the TCP coils.

[0015] In one embodiment, a hybrid frequency plasma system is provided. The hybrid frequency plasma system includes a first matchless plasma source that generates a first sinusoidal waveform. The first sinusoidal waveform is generated based on a first rectangular waveform and has a first frequency. The hybrid frequency plasma system includes a first filter coupled to the first matchless plasma source. The first filter filters out a second frequency so as not to interfere with the first sinusoidal waveform. The hybrid frequency plasma system further includes a first capacitive circuit coupled to the first filter. The first capacitive circuit outputs a first RF signal by balancing the reactance of the first filter with the reactance of the RF coil in the plasma chamber. The first capacitive circuit provides the first RF signal to a point coupled to the RF coil. The hybrid frequency plasma system includes a second matchless plasma source that generates a second sinusoidal waveform. The second sinusoidal waveform is generated based on a second rectangular waveform and has a second frequency. The hybrid frequency plasma system includes a second filter coupled to the second matchless plasma source. The second filter filters the first frequency so as not to interfere with the second sinusoidal waveform. The hybrid frequency plasma system includes a second capacitive circuit coupled to the second filter. The second capacitive circuit balances the reactance of the second filter with the reactance of the RF coil to output a second RF signal. The second capacitive circuit provides the second RF signal to the point.

[0016] In one embodiment, a hybrid frequency plasma system is provided. The hybrid frequency plasma system includes a matchless plasma source that generates a sinusoidal waveform. The sinusoidal waveform is generated based on a rectangular waveform and has a first frequency. The hybrid frequency plasma system further includes a first filter coupled to the matchless plasma source. The first filter filters out a second frequency so as not to interfere with the sinusoidal waveform. The hybrid frequency plasma system includes a capacitive circuit coupled to the first filter. The capacitive circuit balances the reactance of the first filter with the reactance of the RF coil in the plasma chamber to output a first RF signal. The capacitive circuit provides the first RF signal to a point coupled to the RF coil. The hybrid frequency plasma system includes a source RF generator that generates a second RF signal having a second frequency. The hybrid frequency plasma system includes an impedance matching network coupled to the source RF generator. The impedance matching network receives the second RF signal and modifies the impedance of the second RF signal to output a modified RF signal. The impedance matching network includes a second filter that filters the first frequency so as not to interfere with the second RF signal. The impedance matching network provides the modified RF signal to the point.

[0017] In one embodiment, a hybrid frequency plasma system is provided. The hybrid frequency plasma system includes a first matchless plasma source that generates a first sinusoidal waveform. The first sinusoidal waveform is generated based on a first rectangular waveform and has a first frequency. The hybrid frequency plasma system further includes a first filter coupled to the first matchless plasma source. The first filter filters out a second frequency so as not to interfere with the first sinusoidal waveform. The hybrid frequency plasma system includes a first capacitive circuit coupled to the first filter. The first capacitive circuit outputs a first RF signal by balancing the reactance of the first filter with the reactance of a first RF coil in the plasma chamber. The first capacitive circuit provides the first RF signal to a point. The hybrid frequency plasma system includes a second matchless plasma source that generates a second sinusoidal waveform. The second sinusoidal waveform is generated based on a second rectangular waveform and has a second frequency. The hybrid frequency plasma system has a second filter coupled to the second matchless plasma source. A second filter filters the first frequency so as not to interfere with the second sinusoidal waveform. The hybrid frequency plasma system includes a second capacitive circuit coupled to the second filter. The second capacitive circuit outputs a second RF signal by balancing the reactance of the second filter, the reactance of the first RF coil, and the reactance of the second RF coil in the plasma chamber. The hybrid frequency plasma system includes a signal divider coupled to the second capacitive circuit. The signal divider divides the second RF signal into a third RF signal and a fourth RF signal. The signal divider also includes a third capacitive circuit and a fourth capacitive circuit. The third capacitive circuit receives the third RF signal and provides a fifth RF signal to the point by balancing the reactance of the first RF coil in the plasma chamber and the reactance of the second filter. The fourth capacitive circuit receives the fourth RF signal and balances the reactance of the second RF coil with the reactance of the second filter to provide the sixth RF signal to the second RF coil.

[0018] Some advantages of the systems and methods described herein include increased plasma stability. Plasma instability occurs in different regions of the operating space spread across the ICP coil, each with a single frequency (e.g., low or high frequency). By having two RF frequencies available on the same ICP coil, the stability window is expanded to a combination of at least two individual stability windows. Therefore, if one radio frequency is stable, the unstable radio frequency can be avoided. Furthermore, by applying two frequencies simultaneously, a stable window can be created.

[0019] Further advantages of the systems and methods described herein include lower coil voltages and sputtering of smaller windows. Typically, the ICP coil voltage decreases when low frequencies are applied. By replacing some of the high-frequency power with low-frequency power while maintaining the same plasma density, the ICP coil voltage can be lowered below the sputtering threshold of the dielectric window, thereby extending the lifetime of the dielectric window.

[0020] A further advantage of the systems and methods described herein is rapid plasma ignition. A coil voltage higher than the amount of voltage used to maintain the plasma is applied to strike the plasma. Rapid plasma ignition is achieved by applying a high frequency. A high frequency can be used to strike the plasma at the initial power-on, and then the power can be partially or completely switched to a low frequency to maintain the plasma.

[0021] Further advantages of the systems and methods described herein include increased control over uniformity when processing substrates and increased control over the gradient of plasma ions as they enter the substrate. Under many process conditions, the plasma density profiles differ when two frequencies are applied to the same ICP coil. Making two frequencies available provides a further adjustment knob for etching and gradient uniformity.

[0022] Other aspects will become apparent from the following detailed description, which is to be construed in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0023] Embodiments are understood by reference to the following description, which is to be construed in conjunction with the accompanying drawings.

[0024] [Figure 1] FIG. 1 is a diagram of one embodiment of a system for exemplifying a hybrid matchless plasma source (MPS).

[0025] [Figure 2A] FIG. 2A is a diagram of one embodiment of a low-pass filter.

[0026] [Figure 2B] FIG. 2B is a diagram of one embodiment of a high-pass filter.

[0027] [Figure 2C] FIG. 2C is a diagram of one embodiment of a band-pass filter.

[0028] [Figure 2D] FIG. 2D is a diagram of one embodiment of a band-pass filter.

[0029] [Figure 3A] FIG. 3A is a diagram of one embodiment of a plasma system for exemplifying the use of a low-frequency (LF) MPS and a high-frequency (HF) MPS within the plasma system.

[0030] [Figure 3B] FIG. 3B is a diagram of one embodiment of a plasma system for exemplifying the use of LFMPS and HFMPS when the lower electrode is coupled to the ground potential.

[0031] [Figure 4]Figure 4 is a diagram illustrating one embodiment of the system to illustrate the use of an LF source radio frequency generator (RFG) and an HF source RFG for supplying RF power to an RF coil.

[0032] [Figure 5A] Figure 5A is a diagram of one embodiment of a dual-frequency matching circuit.

[0033] [Figure 5B] Figure 5B shows an embodiment of another dual-frequency matching circuit.

[0034] [Figure 5C] Figure 5C shows yet another embodiment of a dual-frequency matching circuit.

[0035] [Figure 6A] Figure 6A is a diagram of one embodiment of a plasma system having an LF-biased RFG and an HF-biased RFG to illustrate the use of an LF-source RFG and an HF-source RFG.

[0036] [Figure 6B] Figure 6B shows an embodiment of a system having a plasma chamber with a lower electrode coupled to ground potential, illustrating the use of an LF source RFG and an HF source RFG.

[0037] [Figure 7A] Figure 7A is a diagram illustrating one embodiment of a system having an HF source RFG to illustrate the use of LFMPS.

[0038] [Figure 7B] Figure 7B is a diagram illustrating one embodiment of a system having HFMPS to illustrate the use of an LF source RFG.

[0039] [Figure 8A] Figure 8A is a diagram of one embodiment of a system having an LF bias RFG and an HF bias RFG to illustrate the use of an LF RFG and an HF source RFG.

[0040] [Figure 8B] Figure 8B is a diagram illustrating one embodiment of the system to illustrate the use of the LFMPS and HF source RFG when the lower electrode is coupled to ground potential.

[0041] [Figure 8C] Figure 8C shows an embodiment of a system having an LF bias RFG and an HF bias RFG to illustrate the use of an LF source RFG and HFMPS.

[0042] [Figure 8D] Figure 8D is a diagram illustrating one embodiment of the system to illustrate the use of LF sources RFG and HFMPS when the lower electrode is coupled to ground potential.

[0043] [Figure 9A] Figure 9A is a diagram illustrating one embodiment of a system that provides high frequencies to multiple RF coils and low frequencies and high frequencies to RF coils.

[0044] [Figure 9B] Figure 9B is a diagram illustrating one embodiment of a system that provides low frequencies to multiple RF coils and provides both low and high frequencies to an RF coil.

[0045] [Figure 9C] Figure 9C is a diagram of one embodiment of a plasma system illustrating a method for filtering out low frequencies so that they are not applied to the RF coil.

[0046] [Figure 9D] Figure 9D is a diagram illustrating one embodiment of a plasma system to illustrate a method for filtering out high frequencies so that they are not applied to the RF coil.

[0047] [Figure 10A]Figure 10A is a diagram of one embodiment of a plasma system illustrating the use of a signal divider within the plasma system.

[0048] [Figure 10B] Figure 10B illustrates an embodiment of a plasma system having a plasma chamber in which the lower electrode is coupled to ground potential, illustrating the use of the signal divider shown in Figure 10A.

[0049] [Figure 10C] Figure 10C is a diagram of one embodiment of a plasma system to illustrate the use of a different signal divider.

[0050] [Figure 10D] Figure 10D illustrates an embodiment of a plasma system having a plasma chamber in which the lower electrode is coupled to ground potential, illustrating the use of the signal divider in Figure 10C.

[0051] [Figure 11A] Figure 11A is an example of a graph illustrating a clock signal.

[0052] [Figure 11B] Figure 11B is an embodiment of a graph illustrating the parameters of an RF signal generated by an LFMPS, LF bias RFG, or LF source RFG.

[0053] [Figure 11C] Figure 11C is an embodiment of a graph illustrating the parameters of an RF signal generated by an HFMPS, HF bias RFG, or HF source RFG.

[0054] [Figure 11D] Figure 11D is an example of a graph illustrating a low-frequency RF signal.

[0055] [Figure 11E]Figure 11E is an example of a graph illustrating a high-frequency RF signal.

[0056] [Figure 11F] Figure 11F is one embodiment of the RF signal graph shown in Figure 11D.

[0057] [Figure 11G] Figure 11G is an example of a graph illustrating the pulse output of an RF signal that is out of phase with the pulse output of the RF signal in Figure 11F.

[0058] [Figure 11H] Figure 11H is an embodiment of the RF signal graph in Figure 11D.

[0059] [Figure 11I] Figure 11I is a graph illustrating one embodiment of how the pulse output frequency of the RF signal parameters in Figure 11F differs from the pulse output frequency of the RF signal parameters.

[0060] [Figure 12A-1] Figure 12A-1 is a diagram illustrating one embodiment of the system to illustrate the details of the MPS.

[0061] [Figure 12A-2] Figure 12A-2 is a diagram illustrating one embodiment of the system to illustrate further details of the input and output sections of the MPS shown in Figure 12A-1.

[0062] [Figure 12B] Figure 12B is a diagram illustrating one embodiment of the system to illustrate the details of the RF generator.

[0063] [Figure 13] Figure 13 is a diagram illustrating one embodiment of the system for illustrating the control of a variable capacitor.

[0064] [Figure 14]Figure 14 is a diagram of one embodiment of a plasma chamber illustrating a solenoid coil.

[0065] [Figure 15] Figure 15 shows an embodiment of a plasma system illustrating the use of LFMPS and HFMPS with a substrate support.

[0066] [Figure 16A] Figure 16A is a diagram illustrating one embodiment of the system to illustrate a master-slave configuration in which LFMPS is the control side and HFMPS is the controlled side.

[0067] [Figure 16B] Figure 16B is a diagram illustrating one embodiment of the system to illustrate a master-slave configuration in which HFMPS is the control side and LFMPS is the controlled side.

[0068] [Figure 16C] Figure 16C is a diagram illustrating one embodiment of the system to illustrate a master-slave configuration in which the LF source RFG is the control side and HFMPS is the controlled side.

[0069] [Figure 16D] Figure 16D is a diagram illustrating one embodiment of the system to illustrate a master-slave configuration in which the HF source RFG is the control side and LFMPS is the controlled side.

[0070] [Figure 16E] Figure 16E is a diagram illustrating one embodiment of the system to illustrate a master-slave configuration in which LFMPS is the control side and HF source RFG is the controlled side.

[0071] [Figure 16F] Figure 16F is a diagram illustrating one embodiment of the system, illustrating a master-slave configuration in which HFMPS is the control side and LF source RFG is the controlled side. [Modes for carrying out the invention]

[0072] The following embodiments describe systems and methods for providing a hybrid frequency plasma source. It will be understood that these embodiments can be implemented even if some or all of these specific details are omitted. In other examples, well-known operations are not described in detail so as not to unnecessarily obscure these embodiments.

[0073] Figure 1 shows an embodiment of system 100 illustrating a hybrid matchless plasma source (MPS). The hybrid MPS is a dual-frequency MPS. System 100 includes a low-frequency (LF) MPS 102 and a high-frequency (HF) MPS 104. The combination of LFMPS 102 and HFMPS 104 constitutes the hybrid MPS. System 100 further includes a first filter 106 and a second filter 108. System 100 also includes a first capacitor 110 and a second capacitor 112. The first capacitor 110 may be referred to herein as a capacitive circuit, and the second capacitor may be referred to herein as a capacitive circuit. For example, each capacitor may be referred to herein as a fixed capacitor or a variable capacitor. System 100 also includes a radio frequency (RF) coil 114. As used herein, RF coils may be referred to as inductively coupled plasma (ICP) coils or transformer-coupled plasma (TCP) coils. The RF coil 114 is an example of an upper electrode of the plasma chamber and has one or more turns or windings.

[0074] An example of a low-frequency MPS is a matchless plasma source that operates at low frequencies, such as those in the range of 400 kHz to 2 megahertz (MHz) and including those frequencies, to generate RF signals with low frequencies. For example, the operating frequency of a low-frequency MPS is 400 kHz or 2 MHz. An example of a high-frequency MPS is a matchless plasma source that operates at high frequencies, such as those in the range of 12 MHz to 60 MHz and including those frequencies, to generate RF signals with high frequencies. For example, the operating frequency of a high-frequency MPS is 13.56 MHz, 27 MHz, or 60 MHz. An example of a capacitor used herein is a fixed capacitor or a variable capacitor. As an example, high frequencies are greater than low frequencies and are excluded from low frequencies. For example, high-frequency values ​​will never coincide with low-frequency values. An example of the first filter 106 is a low-pass filter or a band-pass filter, and an example of the second filter 108 is a high-pass filter or a band-pass filter.

[0075] LFMPS102 is coupled to the first filter 106, and the first filter 106 is coupled to the first capacitor 110. Similarly, HFMPS104 is coupled to the second filter 108, and the second filter 108 is coupled to the second capacitor 112. Capacitors 110 and 112 are coupled to each other at point 122. An example of point 122 is a connector or other connection between the first RF connection, the second RF connection, and the third RF connection. The first RF connection is between the first capacitor 110 and point 122, the second RF connection is between the second capacitor 112 and point 122, and the third RF connection is between point 122 and the RF coil 114. For example, point 122 is the solder between the first, second, and third RF straps. The first RF strap is an example of a first RF connection, the second RF strap is an example of a second RF connection, and the third RF strap is an example of a third RF connection. Another example is point 122, a bolt connecting the first, second, and third RF straps. Point 122 is coupled to end E1 of the RF coil 114 via RF connection 125. Examples of RF connections used herein include RF cables, RF straps, RF cylinders, RF transmission lines, and combinations of two or more thereof. For example, an RF strap is elongated and flat. Further example, an RF strap is rectangular. For example, an RF cable has an RF sheath and an RF conductor. The opposite end E2 of the RF coil 114 is coupled to ground potential.

[0076] LFMPS102 generates an RF signal 116A and supplies the RF signal 116A to the first filter 106. The RF signal 116A is a sine wave. For example, the RF signal 116A has the shape of a sine wave signal. The first filter 106 passes the low frequencies of the RF signal 116A and outputs a filtered signal 118A. For example, the low frequencies of the filtered signal 118A are the same as the low frequencies of the RF signal 116A.

[0077] The first filter 106 provides the filtered signal 118A to the first capacitor 110. The first capacitor 110 receives the filtered signal 118A and provides the output RF signal 120A. For example, the first capacitor 110 has capacitance that balances the reactance of the first filter 106 with respect to the reactance of the RF coil 114. For example, the first capacitor 110 has capacitance that achieves a first reactance of the first filter 106 and a second reactance of the RF coil 114. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude opposite to the direction of the second reactance. In this example, the capacitance of the first capacitor 110 results in a low low-frequency resonant frequency of the LFMPS 102. In another example, the first capacitor 110 has capacitance that cancels out the reactance of the first filter 106 with respect to the reactance of the RF coil 114. For example, the first capacitor 110 has a capacitance that achieves the first reactance of the first filter 106 and the second reactance of the RF coil 114. In this example, the first reactance has the same amplitude as the second reactance, but in opposite directions. In this example, the capacitance of the first capacitor 110 lowers the low-frequency resonant frequency of the LFMPS 102. The output RF signal 120A is supplied from the capacitor 110 to point 122.

[0078] For example, the first reactance described herein has a first sign (e.g., a positive or negative sign), and the second reactance described herein has a second sign (e.g., a negative or positive sign). In this example, the second sign is the opposite of the first sign. For example, when the first reactance is positive, the second reactance is negative, and when the first reactance is negative, the second reactance is positive. Another example is when the first reactance is a positive value, the second reactance is a negative value, and when the first reactance is a negative value, the second reactance is a positive value.

[0079] Similarly, HFMPS104 generates an RF signal 116B and supplies the RF signal 116B to a second filter 108. The RF signal 116B is a sine wave. For example, the RF signal 116B has the shape of a sine wave signal. The second filter 108 passes the high frequencies of the RF signal 116B and outputs a filtered signal 118B. For example, the high frequencies of the filtered signal 118B are the same as the high frequencies of the RF signal 116B.

[0080] The second filter 108 provides the filtered signal 118B to the second capacitor 112. The second capacitor 112 receives the filtered signal 118B and provides the output RF signal 120B. For example, the second capacitor 112 has capacitance that balances the reactance of the second filter 108 with respect to the reactance of the RF coil 114. For example, the second capacitor 112 has capacitance that achieves a first reactance of the second filter 108 and a second reactance of the RF coil 114. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude opposite to the direction of the second reactance. In this example, the capacitance of the second capacitor 112 results in a high-frequency resonant frequency of the HFMPS 104. In another example, the second capacitor 112 has capacitance that cancels out the reactance of the second filter 108 with respect to the reactance of the RF coil 114. To illustrate further, the second capacitor 112 has capacitance that achieves the first reactance of the second filter 108 and the second reactance of the RF coil 114. In this example, the first reactance has the same amplitude as the second reactance, but in opposite directions. In this example, the capacitance of the second capacitor 112 results in a high-frequency resonant frequency of the HFMPS 104. The second capacitor 112 provides the output RF signal 120B to point 122. The output RF signals 120A and 120B are combined at point 122 to produce a combined RF signal 123, which is supplied to terminal E1.

[0081] Plasma is generated or maintained within the plasma chamber when one or more process gases are supplied to the plasma chamber in addition to the output RF signals 120A and 120B. Examples of one or more process gases include oxygen-containing gases, nitrogen-containing gases, fluorine-containing gases, and two or more combinations thereof.

[0082] The RF power from the plasma is reflected in the form of a reflected RF signal 115. The reflected RF signal 115 is received by point 122 from the plasma in the plasma chamber and split into reflected RF signals 124A and 124B. The RF power of reflected RF signal 115 is reflected from the plasma chamber towards point 122 via RF coil 114. Reflected RF signal 124A is supplied from point 122 to a second capacitor 112. Reflected RF signals 115 and 124A have a low-frequency and high-frequency combination. The second capacitor 112 modifies the impedance of reflected RF signal 124A and supplies the output RF signal 126A to filter 108. For example, the second capacitor 112 balances the reactance between RF coil 114 and second filter 108 in the same manner as described above to supply the output RF signal 126A. For example, the second capacitor 112 reduces the impedance of the reflected RF signal 124A to a minimum amount, such as zero or near zero, and provides the output RF signal 126A to the second filter 108. The second filter 108 filters out the low frequencies of the output RF signal 126A and outputs the filtered signal 128A. Examples of filtering out frequencies include removing the frequency. Examples of filtering out frequencies include lowering the frequency. The filtered signal 128A has a small amount of low frequencies, or zero low frequencies, to protect the HFMPS 104 from damage caused by low frequencies.

[0083] Similarly, the reflected RF signal 124B is reflected from point 122 to the first capacitor 110. The reflected RF signal 124B has a combination of low and high frequencies. The first capacitor 110 modifies the impedance of the reflected RF signal 124B and provides the output RF signal 126B to the first filter 106. For example, the first capacitor 110 provides the output RF signal 126B by balancing the reactance between the RF coil 114 and the first filter 106 in the same output manner as described above. For example, the first capacitor 110 reduces the impedance of the reflected RF signal 124B to a minimum amount, such as zero or near zero, and provides the output RF signal 126B to the first filter 106. The first filter 106 filters out the high frequencies of the output RF signal 126B, such as by lowering or removing them, and outputs the filtered signal 128B. The filtered signal 128B has a low or zero amount of high frequencies to protect the LFMPS102 from damage caused by high frequencies.

[0084] The first filter 106 filters out high frequencies, but high frequencies include a certain range of frequencies. For example, the first filter 106 filters out frequencies within a predetermined range from high frequencies. For example, in order to filter out the 27MHz high frequency of the output RF signal 126B, the first filter 106 removes frequencies in the range of 26.7MHz to 27.3MHz. Similarly, the second filter 108 filters out low frequencies, but low frequencies include a certain range of frequencies. For example, the second filter 108 filters out frequencies within a predetermined range from low frequencies. For example, in order to filter out the 400kHz low frequency of the output RF signal 126A, the second filter 108 filters out frequencies in the range of 380kHz to 430kHz.

[0085] It should be further noted that there is no matching device, such as an impedance matching network, impedance matching circuit, impedance matching system, impedance matching electrical circuit, or impedance matching device, between the LFMPS102 and the RF coil 114. For example, there is no physical housing, such as a matching device enclosure or physical container, between the LFMPS102 and the RF coil 114. Similarly, there is no matching device between the HFMPS104 and the RF coil 114. For example, there is no physical housing, such as a matching device enclosure or physical container, between the HFMPS104 and the RF coil 114.

[0086] In one embodiment, a substrate support such as a chuck is used instead of the RF coil 114. The chuck is made of a metal such as aluminum or an aluminum alloy.

[0087] In one embodiment, the system 100 does not include the first filter 106. In this embodiment, the LFMPS 102 is coupled to the first capacitor 110 but not to the first filter 106.

[0088] In one embodiment, the system 100 does not include a second filter 108. In this embodiment, the HFMPS 104 is coupled to the second capacitor 112 but not to the second filter 108.

[0089] In one embodiment, LFMPS102 is coupled to the first filter 106 via an RF connector, the first filter 106 is coupled to the first capacitor 110 via an RF connector, and the first capacitor 110 is coupled to point 122 via an RF connector. Similarly, HFMPS104 is coupled to the second filter 108 via an RF connector, the second filter 108 is coupled to the second capacitor 112 via an RF connector, and the second capacitor 112 is coupled to point 122 via an RF connector. In this embodiment, RF signals 116A and 128B are transmitted between LFMPS102 and the first filter 106 via an RF connector between LFMPS102 and the first filter 106. RF signals 118A and 126B are transmitted between the first filter 106 and the first capacitor 110 via an RF connection between the first filter 106 and the first capacitor 110. Furthermore, RF signals 120A and 124B are transmitted between the first capacitor 110 and point 122 via the RF connection between the first capacitor 110 and point 122. Furthermore, RF signals 116B and 128A are transmitted between the HFMPS 104 and the second filter 108 via the RF connection between the HFMPS 104 and the second filter 108. Also, RF signals 118B and 126A are transmitted between the second filter 108 and the second capacitor 112 via the RF connection between the second filter 108 and the second capacitor 112. Furthermore, RF signals 120B and 124A are transmitted between the second capacitor 112 and point 122 via the RF connection between the second capacitor 112 and point 122.

[0090] In one embodiment, a lower electrode, such as a plate or ring within a substrate support, is used instead of the RF coil 114. For example, point 122 is coupled to the lower electrode. Examples of lower electrodes and substrate supports will be described later.

[0091] In one embodiment, HFMPS104 is turned on to generate RF signal 116B for a predetermined time, while LFMPS102 remains off. If plasma is ignited or struck in the plasma chamber within the predetermined time, LFMPS102 is turned on and RF signal 116A is generated. When LFMPS102 is turned on, HFMPS104 is either turned off or remains on.

[0092] In one embodiment, LFMPS102 is turned on to generate RF signal 116A for a predetermined time, and HFMPS104 is turned on to generate RF signal 116B for a predetermined time. If plasma is ignited or struck in the plasma chamber within the predetermined time, HFMPS104 is turned off or remains on.

[0093] In one embodiment, LFMPS is used instead of HFMPS104. The operating frequency of LFMPS is the same as that of LFMPS102.

[0094] In one embodiment, HFMPS is used instead of LFMPS102. The operating frequency of HFMPS is the same as that of HFMPS104.

[0095] In one embodiment, terminal E2 of the RF coil 114 is coupled to ground potential via a termination capacitor. For example, terminal E2 of the RF coil 114 is coupled to the first terminal of the termination capacitor, and the second terminal of the termination capacitor is coupled to ground potential.

[0096] Figure 2A is a diagram of one embodiment of the low-pass filter 200. Filter 200 is an example of the first filter 106 in Figure 1. Filter 200 includes an inductor 202, another inductor 204, a capacitor 206, and another capacitor 208.

[0097] The input In of filter 200 is coupled to LFMPS102, and the output Out of filter 200 is coupled to the first capacitor 110 (Figure 1). The input In of filter 200 is coupled to inductor 202, which is coupled to inductor 204 and the first terminal of capacitor 206. Inductor 204 is coupled to the output Out of filter 200 and the first terminal of capacitor 208. The first terminal of capacitor 208 is coupled to the output Out of filter 200. The second terminal of capacitor 208 is coupled to ground potential, and the second terminal of capacitor 206 is coupled to ground potential.

[0098] The first filter 200 receives the RF signal 116A, passes the low frequencies of the RF signal 116A through, and outputs the filtered RF signal 118A. The filter 200 also receives the output RF signal 126B at its output Out, filters out the high frequencies of the output RF signal 126B, and provides the filtered signal 128B at its input In.

[0099] Figure 2B shows one embodiment of the high-pass filter 230. Filter 230 is an example of the second filter 108 in Figure 1. Filter 230 includes capacitors 232 and 234, inductor 236, and inductor 238.

[0100] The input In of filter 230 is coupled to HFMPS104, and the output Out of filter 230 is coupled to the second capacitor 112 (Figure 1). The input In of filter 230 is coupled to capacitor 232, which is coupled to the first terminal of inductor 236 and to capacitor 234. Capacitor 234 is coupled to the output Out of filter 230 and the first terminal of inductor 238. The second terminal of inductor 236 is coupled to ground potential, and the second terminal of inductor 238 is coupled to ground potential.

[0101] The first filter 230 receives the RF signal 116B, passes the high frequencies of the RF signal 116B through, and outputs the filtered RF signal 118B. The filter 230 also receives the output RF signal 126A at its output Out, filters out the low frequencies of the output RF signal 126A, and provides the filtered signal 128A at its input In.

[0102] Figure 2C shows an embodiment of a bandpass filter 250, such as a low-pass filter or a high-pass filter. Filter 250 is an example of the first filter 106 or the second filter 108 in Figure 1. Filter 250 includes an inductor 252, another inductor 254, an inductor 256, a capacitor 258, a capacitor 260, and a capacitor 262.

[0103] When filter 250 is used as the first filter 106 (e.g., a low-pass filter), the input In of filter 250 is coupled to LFMPS102, and the output Out of filter 250 is coupled to the first capacitor 110 (Figure 1). When filter 250 is used as the second filter 108 (e.g., a high-pass filter), the input In of filter 250 is coupled to HFMPS104, and the output Out of filter 250 is coupled to the second capacitor 112 (Figure 1).

[0104] The input In of filter 250 is coupled to inductor 252, which is coupled in series with capacitor 258. Capacitor 258 is coupled to the first end of capacitor 260, the first end of inductor 256, and inductor 254. The first end of capacitor 260 is coupled to the first end of inductor 256 and inductor 254. Inductor 254 is coupled in series with capacitor 262, which is coupled to the output Out of filter 250. The second end of capacitor 260 is coupled to ground potential, and the second end of inductor 256 is coupled to ground potential.

[0105] When filter 250 is used as the first filter 106, filter 250 receives the RF signal 116A, passes the low frequencies of the RF signal 116A through, and outputs the filtered RF signal 118A. Filter 250 also receives the output RF signal 126B at its output Out, filters out the high frequencies of the output RF signal 126B, and provides the filtered signal 128B at its input In.

[0106] When filter 250 is used as a second filter 108, filter 250 receives the RF signal 116B, passes the high frequencies of RF signal 116B through, and outputs the filtered RF signal 118B. In this case, filter 250 receives the output RF signal 126A at its output Out, filters out the low frequencies of the output RF signal 126A, and provides the filtered signal 128A at its input In.

[0107] Figure 2D shows one embodiment of a bandpass filter 270, such as a low-pass filter or a high-pass filter. The bandpass filter 270 is a series resonant circuit. Filter 270 is an example of the first filter 106 or 108 in Figure 1. Filter 270 includes an inductor 272 and a capacitor 274 coupled in series with each other.

[0108] When filter 270 is used as a low-pass first filter 106, the input In of filter 270 is coupled to LFMPS102, and the output Out of filter 270 is coupled to the first capacitor 110 (Figure 1). When filter 270 is used as a high-pass second filter 108, the input In of filter 270 is coupled to HFMPS104, and the output Out of filter 270 is coupled to the second capacitor 112 (Figure 1).

[0109] The input In of filter 270 is coupled to inductor 272, which is coupled in series with capacitor 274. Capacitor 274 is coupled to the output Out of filter 270.

[0110] When filter 270 is used as the first filter 106, filter 270 receives the RF signal 116A, passes the low frequencies of the RF signal 116A through, and outputs the filtered RF signal 118A. Filter 270 also receives the output RF signal 126B at its output Out, filters out the high frequencies of the output RF signal 126B, and provides the filtered signal 128B at its input In.

[0111] When filter 270 is used as a second filter 108, filter 270 receives the RF signal 116B, passes the high frequencies of RF signal 116B through, and outputs the filtered RF signal 118B. In this case, filter 270 receives the output RF signal 126A at its output Out, filters out the low frequencies of the output RF signal 126A, and provides the filtered signal 128A at its input In.

[0112] Figure 3A is a diagram of one embodiment of the plasma system 300 to illustrate the use of LFMPS102 and HFMPS104 within the plasma system 300. The plasma system 300 includes LFMPS102, HFMPS104, a first filter 106, a second filter 108, a first capacitor 110, a second capacitor 112, an LF bias RF generator (RFG) 302, an HF bias RFG 304, a matching unit 306, and a plasma chamber 308.

[0113] An example of an LF-biased RFG is an RF generator that operates at a low frequency and produces an RF signal with a low frequency. For example, the operating frequency of LF-biased RFG302 is different from the operating frequency of LFMPS102. For example, the operating frequency of LF-biased RFG302 is 2 MHz, and the operating frequency of LFMPS102 is 400 kHz. Another example is that the frequency of the RF signal produced by LF-biased RFG302 is the same as (e.g., equal to) the frequency of RF signal 116A produced by LFMPS102. Similarly, an example of an HF-biased RFG304 is an RF generator that operates at a high frequency and produces an RF signal with a high frequency. For example, the operating frequency of HF-biased RFG304 is different from the operating frequency of HFMPS104. For example, the operating frequency of HF-biased RFG304 is 60 MHz, and the operating frequency of HFMPS104 is 27 MHz. Another example is that the operating frequency of HF-biased RFG304 is the same as the operating frequency of HFMPS104.

[0114] The matching devices described herein include one or more branch circuits. For example, a matching device has a housing or enclosure. Examples of matching devices include impedance matching networks and impedance matching circuits. For example, each branch circuit of a matching device includes one or more electrical circuit components, such as inductors, resistors, and capacitors. For further example, each branch circuit includes a series circuit, or a shunt circuit, or a combination thereof. A shunt circuit is coupled to a series circuit at one end and to ground potential at the other end. For example, a series circuit includes two or more electrical circuit components coupled in series with each other, and a shunt circuit includes two or more electrical circuit components coupled in series with each other. For another example, a series circuit includes at least one electrical component, and a shunt circuit includes at least one electrical circuit component.

[0115] The matching circuit 306 includes a first branch circuit coupled between input 324A and output 326 of the matching circuit 306. The matching circuit 306 also includes a second branch circuit coupled between another input 324B and output 326 of the matching circuit 306.

[0116] The plasma chamber 308 includes a substrate support 310 and an RF coil 312. A substrate S, such as a semiconductor wafer, is placed on the upper surface of the substrate support 310. The RF coil 312 has two turns and is an example of an RF coil 114 (Figure 1). An example of the substrate support 310 is a chuck such as an electrostatic chuck (ESC). The substrate support 310 includes a lower electrode 311, which is made of a metal such as aluminum or an aluminum alloy. The plasma chamber 308 has a dielectric window 314. For example, the dielectric window 314 forms the upper wall of the plasma chamber 308. The RF coil 312 is located above the dielectric window 314.

[0117] Point 122 is coupled to end 316 of the RF coil 312 via RF connector 125. The opposite end 318 of the RF coil 312 is coupled to ground potential.

[0118] The LF bias RFG302 is coupled to input 324A of the matching unit 306 via RF cable 320, and the HF bias RFG304 is coupled to input 324B of the matching unit 306 via RF cable 322. The output 326 of the matching unit 306 is connected to the board via RF transmission line 328. support It is coupled to the lower electrode 311 of 310. An example of an RF transmission line used herein is an RF rod enclosed in an RF sheath. An insulating material is present between the RF rod and the RF sheath. Another example of an RF transmission line is a combination of an RF rod and one or more RF straps. For example, the RF rod is enclosed in an RF sheath, coupled to the lower electrode 311, and coupled to the output 326 via RF straps.

[0119] The combined RF signal 123 is transmitted from point 122 to terminal 316 via RF connection 125. The LF bias RFG 302 generates RF signal 330 and transmits RF signal 330 to input 324A. Similarly, the HF bias RFG 304 generates RF signal 332 and transmits RF signal 332 to input 324B via RF cable 322. The matching unit 306 receives RF signals 330 and 332 and corrects the impedance of RF signals 330 and 332 to match the impedance of the load coupled to output 326 with the impedance of the sources coupled to inputs 324A and 324B. Examples of loads coupled to output 326 include RF transmission line 328 and plasma chamber 308. Examples of sources coupled to inputs 324A and 324B include RF cables 320 and 322, as well as bias RF generators 302 and 304. The impedance of RF signal 330 is corrected by the first branch circuit of the matching circuit 306 to output a first corrected RF signal, and the impedance of RF signal 332 is corrected by the second branch circuit of the matching circuit 306 to output a second corrected RF signal. The first and second corrected RF signals are combined at output 326, for example by being added together, to provide a corrected RF signal 334 at output 326. The corrected RF signal 334 is transmitted from output 326 to the lower electrode 311 via the RF transmission line 328.

[0120] Plasma is generated or maintained within the plasma chamber 308 when one or more process gases are supplied to the plasma chamber 308 in addition to the combined RF signals 123 and 334. While plasma is generated or maintained within the plasma chamber 308, the substrate S is processed and the reflected RF signal 115 is reflected from the plasma chamber 308 towards point 122 via the RF connection 125. For example, the reflected RF signal 115 is reflected from the plasma chamber 308 towards point 122 via the RF connection 125. Examples of processing the substrate S include depositing a metal or oxide on top of the substrate S, etching the substrate S, cleaning the substrate S, and sputtering the substrate S.

[0121] In one embodiment, the RF coil 312 has a different number of turns than that shown in Figure 3A.

[0122] In one embodiment, each turn of the RF coil 312 is in a different plane.

[0123] Figure 3B is a diagram of one embodiment of the plasma system 350 illustrating the use of the LFMPS102 and HFMPS104 when the lower electrode 311 is coupled to ground potential. The plasma system 350 includes the LFMPS102, HFMPS104, a first filter 106, a second filter 108, a first capacitor 110, a second capacitor 112, and a plasma chamber 308. While the lower electrode 311 is coupled to ground potential, a combined RF signal 123 is generated in the same manner as described above and supplied to the RF coil 312.

[0124] Plasma is generated or maintained within the plasma chamber 308 when one or more process gases are supplied to the plasma chamber 308 in addition to the combined RF signal 123. As the plasma is generated or maintained, the reflected RF signal 115 is reflected from the plasma chamber 308 toward point 122.

[0125] Figure 4 is a diagram of one embodiment of system 400 illustrating the use of an LF source RFG402 and an HF source RFG404 to supply RF power to the RF coil 114. System 400 uses an LF source RFG402 and an HF source RFG404. source The system includes RFG404. The system 400 further includes a dual-frequency matcher 406 and an RF coil 114.

[0126] An example of an LF source RFG is an RF generator that operates at a low frequency and produces an RF signal having a low frequency. For example, the operating frequency of LF source RFG 402 is different from the operating frequency of LFMPS 102 (Figure 1). For further example, the operating frequency of LF source RFG is 2 MHz, and the operating frequency of LFMPS 102 is 400 kHz. Another example is that the frequency of RF signal 420 generated by LF source RFG 402 is different from the frequency of RF signal 116A generated by LFMPS 102. For yet another example, the frequency of RF signal 420 generated by LF source RFG 402 is the same as (e.g., equal to) the operating frequency of LFMPS 102.

[0127] Similarly, an example of an HF source RFG404 is an RF generator that operates at a high frequency and generates RF signals with high frequencies. For example, the operating frequency of the HF source RFG404 is different from the operating frequency of the HFMPS104. For example, the operating frequency of the HF source RFG404 is 60 MHz, and the operating frequency of the HFMPS104 is 27 MHz. Another example is when the operating frequency of the HF source RFG404 is the same as the operating frequency of the HFMPS104.

[0128] The LF source RFG 402 is coupled to the input 410 of the dual-frequency matcher 406 via RF cable 408, and the HF source RFG is coupled to another input 414 of the dual-frequency matcher 406 via another RF cable 412. The output 416 of the dual-frequency matcher 406 is coupled to the end E1 of the RF coil 114 via RF connector 418.

[0129] The LF source RFG402 generates an RF signal 420 and supplies it to input 410 via RF cable 408. RF signal 420 has a low frequency. Furthermore, the HF source RFG404 generates an RF signal 422 and supplies it to input 414 via RF cable 412. RF signal 422 has a high frequency. The dual-frequency matching unit 406 receives RF signals 420 and 422 and corrects the impedance of RF signals 420 and 422 to match the impedance of the load coupled to output 416 with the impedance of the sources coupled to inputs 410 and 414. Examples of loads coupled to output 416 include the RF connector 418 and a plasma chamber including the RF coil 114. Examples of sources coupled to inputs 410 and 414 include RF cables 408 and 412, and source RF generators 402 and 404. The impedance of RF signal 420 is corrected by the first branch circuit of the dual-frequency matcher 406 to output a first corrected RF signal, and the impedance of RF signal 422 is corrected by the second branch circuit of the dual-frequency matcher 406 to output a second corrected RF signal. The first and second corrected RF signals are combined at output 416, for example by adding them together, to provide a corrected RF signal 426 at output 416. The corrected RF signal 426 is transmitted from output 416 to the RF coil 114 via the RF connection unit 418.

[0130] Plasma is generated or maintained within the plasma chamber when one or more process gases are supplied to the plasma chamber, which includes the RF coil 114, in addition to the modified RF signal 426. As the plasma is generated or maintained, the RF power is reflected toward the dual-frequency matcher 406 in the form of a reflected RF signal 428.

[0131] In one embodiment, the HF source RFG404 is turned on to generate an RF signal 422 for a predetermined time, while the LF source RFG402 remains off. When plasma is ignited or struck in the plasma chamber within the predetermined time, the LF source RFG402 is turned on to generate an RF signal 420. When the LF source RFG402 is turned on, the HF source RFG404 is either turned off or remains on.

[0132] In one embodiment, the LF source RFG402 is turned on to generate an RF signal 420 for a predetermined time, and the HF source RFG404 is turned on to generate an RF signal 422 for a predetermined time. If the plasma is ignited or struck in the plasma chamber within the predetermined time, the HF source RFG404 is either turned off or remains on.

[0133] Figure 5A is a diagram of one embodiment of a dual-frequency matching device 500, which is an example of a dual-frequency matching device 406. The dual-frequency matching device 500 includes a branch circuit 501, which includes a filter 506, a shunt circuit 504, a series circuit 507, and another filter 508. The dual-frequency matching device 500 also includes another branch circuit 503, which includes a filter 510, a series circuit 512, a shunt circuit 514, another series circuit 516, and a filter 518. An example of filter 506 is the first filter 106 (Figure 1), and an example of filter 508 is the first filter 106. Similarly, an example of filter 510 is the second filter 108 (Figure 1), and an example of filter 518 is the second filter 108. An example of a shunt circuit is a variable capacitor or a fixed capacitor, and an example of a series circuit is a variable capacitor or a fixed capacitor.

[0134] Filter 506 is coupled to input 410 and the end of shunt circuit 504. The other end of shunt circuit 504 is coupled to ground potential. Filter 506 is coupled to series circuit 507, and series circuit 507 is coupled to filter 508. Filter 108 is coupled to output 416.

[0135] Similarly, filter 510 is coupled to input 414 and the end of series circuit 512. Series circuit 512 is coupled to the end of shunt circuit 514. The opposite end of shunt circuit 514 is coupled to ground potential. Shunt circuit 514 and series circuit 512 are coupled to series circuit 516. Series circuit 516 is coupled to filter 518, and filter 518 is coupled to output 416.

[0136] Filter 506 receives the RF signal 420 at its input, passes the low frequencies of the RF signal 420 through, and outputs the filtered signal 505 at its output. The shunt circuit 504 and the series circuit 507 modify the impedance of the filtered RF signal 505, providing the modified RF signal 509 at the output of the series circuit 507. Filter 508 passes the low frequencies of the modified RF signal 509 through, and outputs the filtered signal 511 at its output.

[0137] Similarly, filter 510 receives RF signal 422 at its input, passes the high frequencies of RF signal 422 through, and outputs filtered RF signal 513 at its output. Series circuit 512, shunt circuit 514, and series circuit 516 modify the impedance of filtered RF signal 513 to provide modified RF signal 515 at the output of series circuit 516. Filter 518 passes the high frequencies of modified RF signal 515 through, and outputs filtered signal 517 at its output. Filtered signal 511 is combined with filtered signal 517, such as by being added together, to generate modified RF signal 426, which is transmitted to RF coil 114 via output 416.

[0138] The reflected RF signal 428 is split at output 416 into reflected RF signal 520 and another reflected RF signal 522. Reflected RF signal 520 is transmitted from output 416 to filter 508, and reflected RF signal 522 is transmitted from output 416 to filter 518.

[0139] The reflected RF signal 520 has high frequencies, and these high frequencies are filtered by filter 508 to provide a filtered signal 524 at the input of filter 508. The impedance of the filtered signal 524 is corrected by the series circuit 507 and the shunt circuit 504 to output a modified RF signal 526. Filter 506 filters out the high frequencies of the modified RF signal 526 to provide a filtered signal 528 at the input of filter 506. As an example, the filtered signal 528 has low frequencies and does not contain high frequencies. As another example, the filtered signal 528 has a minimum amount of high frequencies and a maximum amount of low frequencies. The filtered signal 528 has a minimum amount of high frequencies that interfere with the low frequencies of the RF signal 420, or none at all. When the filtered signal 528 is received by the LF source RFG 402 via the RF cable 408, it does not damage the LF source RFG 402, or causes minimal damage to the LF source RFG 402.

[0140] Similarly, the reflected RF signal 522 has low frequencies, which are filtered by filter 518 to provide a filtered signal 530 at the input of filter 518. The impedance of the filtered signal 530 is corrected by series circuit 516, shunt circuit 514, and series circuit 512 to output a corrected RF signal 532. Filter 510 filters out the low frequencies from the corrected RF signal 532 to provide a filtered signal 534 at the input of filter 510. As an example, the filtered signal 534 has high frequencies and does not contain low frequencies. As another example, the filtered signal 534 has a minimum amount of low frequencies and a maximum amount of high frequencies. The filtered signal 524 has a minimum amount of low frequencies that interfere with the high frequencies of RF signal 422, or none at all. When the filtered signal 534 is received by the HF source RFG 404 via RF cable 412, it does not damage the HF source RFG 404, or causes minimal damage to the HF source RFG 404.

[0141] Figure 5B shows an embodiment of a dual-frequency matcher 550, which is another example of the dual-frequency matcher 406 in Figure 4. The dual-frequency matcher 550 is structurally and functionally the same as the dual-frequency matcher 500 and Figure 5A, except that the dual-frequency matcher 550 does not include filters 508 and 518. Instead, a series circuit 507 is coupled to the output 416, and a series circuit 516 is coupled to the output 416. For example, the dual-frequency matcher 550 includes a branch circuit 531, which includes the filter 506, the shunt circuit 504, and the series circuit 507. Also in this example, two The frequency matching circuit 550 includes a branch circuit 533, which includes a filter 510, a series circuit 512, a shunt circuit 514, and a series circuit 516.

[0142] The impedance of the reflected RF signal 520 is corrected by the series circuit 507 and the shunt circuit 504 to provide the corrected RF signal 552 to the filter 506. The filter 506 performs filtering, such as removing or reducing high frequencies from the corrected RF signal 552, to provide the filtered signal 554 at the input of the filter 506. As an example, the filtered signal 554 has low frequencies and does not contain high frequencies. As another example, the filtered signal 554 has a minimum amount of high frequencies and a maximum amount of low frequencies. The filtered signal 554 has a minimum amount of high frequencies that interfere with the low frequencies of the RF signal 420, or none at all. When the filtered signal 554 is received by the LF source RFG 402 via the RF cable 408, it does not damage the LF source RFG 402, or causes negligible damage to the LF source RFG 402.

[0143] Similarly, the impedance of the reflected RF signal 522 is corrected by the series circuit 516, the shunt circuit 514, and the series circuit 512 to provide the corrected RF signal 555 to the filter 510. The filter 510 performs filtering, such as removing or reducing low frequencies from the corrected RF signal 555, to provide the filtered signal 556 at the input of the filter 510. As an example, the filtered signal 556 has high frequencies and no low frequencies. As another example, the filtered signal 556 has a minimum amount of low frequencies and a maximum amount of high frequencies. The filtered signal 556 has a minimum amount of low frequencies that interfere with the high frequencies of the RF signal 422, or none at all. When the filtered signal 556 is received by the HF source RFG 404 via the RF cable 412, it does not damage the HF source RFG 404, or causes negligible damage to the HF source RFG 404.

[0144] Figure 5C shows an embodiment of a dual-frequency matcher 570, which is yet another example of the dual-frequency matcher 406 in Figure 4. The dual-frequency matcher 570 is structurally and functionally the same as the dual-frequency matcher 500 and Figure 5A, except that the dual-frequency matcher 570 does not include filters 506 and 510. Instead, a shunt circuit 504 and a series circuit 507 are coupled to input 410. Also, a series circuit 512 is coupled to input 414. For example, the dual-frequency matcher 570 includes a branch circuit 571, which includes a shunt circuit 504, a series circuit 507, and a filter 508. Also in this example, the dual-frequency matcher 570 includes a branch circuit 573, which includes a series circuit 512, a shunt circuit 514, a series circuit 516, and a filter 518.

[0145] The modified RF signal 526 is reflected through the RF cable 408 toward the LF source RFG 402 (Figure 4). The modified RF signal 526 is generated based on the filtered signal 524. Thus, as an example, the modified RF signal 526 has low frequencies and no high frequencies. As another example, the modified RF signal 526 has a minimum amount of high frequencies and a maximum amount of low frequencies. The modified RF signal 526 has a minimum amount of high frequencies that interfere with the low frequencies of the RF signal 420, or none at all. When the modified RF signal 526 is received by the LF source RFG 402 through the RF cable 408, it does not damage the LF source RFG 402, or causes negligible damage to the LF source RFG 402.

[0146] Similarly, the modified RF signal 532 is reflected through the RF cable 412 toward the HF source RFG 404 (Figure 4). The modified RF signal 532 is generated based on the filtered signal 530. Thus, as an example, the modified RF signal 532 has high frequencies and no low frequencies. As another example, the modified RF signal 532 has a minimum amount of low frequencies and a maximum amount of high frequencies. The modified RF signal 532 has a minimum amount of low frequencies that interfere with the high frequencies of the RF signal 422, or none at all. When the modified RF signal 532 is received by the HF source RFG 405 through the RF cable 412, it does not damage the HF source RFG 404, or causes negligible damage to the HF source RFG 404.

[0147] Figure 6A is a diagram of one embodiment of a plasma system 600 having LF bias RFG302 and HF bias RFG304 to illustrate the use of LF source RFG402 and HF source RFG404. The plasma system 600 includes LF source RFG402, HF source RFG404, dual frequency matcher 406, plasma chamber 308, LF bias RFG302, HF bias RFG304, and matcher 306.

[0148] The output 416 of the dual-frequency matching unit 406 is coupled to the RF coil 312 of the plasma chamber 308 via the RF connector 418. A modified RF signal 426 is transmitted from the output 416 to the RF coil 312 via the RF connector 418, and a modified RF signal 334 is transmitted from the output 326 to the lower electrode 311 via the RF transmission line 328. One or more process gases are transmitted to the plasma chamber 308 via the modified RF signal 426 When supplied in addition to 334, plasma is generated or maintained within the plasma chamber 308. As the plasma is generated or maintained, the RF power embedded in the reflected RF signal 428 is reflected toward the dual-frequency matcher 406.

[0149] Figure 6B shows one embodiment of a system 650 having a plasma chamber 308 with a lower electrode 311 coupled to ground potential, illustrating the use of an LF source RFG402 and an HF source RFG404. The system 650 includes an LF source RFG402, an HF source RFG404, a dual-frequency matcher 406, and a plasma chamber 308. A modified RF signal 426 is supplied to the plasma chamber 308, and a plasma is generated or maintained within the plasma chamber 308 when one or more process gases are supplied to the plasma chamber 308. The RF power is reflected in the form of a reflected RF signal 428 in the direction from the plasma chamber 308 toward the LF source RFG402 and HF source RFG404.

[0150] Figure 7A is a diagram of one embodiment of a system 700 having an HF source RFG404 to illustrate the use of LFMPS102. System 700 includes LFMPS102, HF source RFG404, first filter 106, first capacitor 110, matching circuit 702, and RF coil 114. Referring to Figure 5A as an example, the matching circuit 702 includes branch circuit 503 but does not include branch circuit 501. Referring to another example, Figure 5B, the matching circuit 702 includes branch circuit 533 but does not include branch circuit 531. Referring to yet another example, Figure 5C, the matching circuit 702 includes branch circuit 573 but does not include branch circuit 571.

[0151] The HF source RFG404 is coupled to a matching unit 702, which is coupled to point 122. Upon receiving an RF signal 422 at its input, the matching unit 702 corrects the impedance of the RF signal 422 and outputs a corrected RF signal 704. For example, upon receiving an RF signal 422 at its input, the matching unit 702 matches the impedance of a load coupled to its output with the impedance of a source coupled to its input and outputs a corrected RF signal 704. An example of a load coupled to the output of the matching unit 702 is a plasma chamber having an RF coil 114. Another example of a load coupled to the output of the matching unit 702 is an RF connection between the output and point 122, another RF connection between point 122 and the RF coil 114, and a plasma chamber including the RF coil 114. An example of a source coupled to the input of the matching unit 702 is the HF source RFG404 and an RF cable 412. The output RF signal 120A and the modified RF signal 704 are combined at point 122, for example, to generate a combined RF signal 706, which is then supplied to the RF coil 114 via the RF connection unit 125.

[0152] Plasma is generated or maintained within the plasma chamber when one or more process gases are supplied to the plasma chamber 308 (Figure 3A) in addition to the combined RF signal 706. As the plasma is generated or maintained, RF power is reflected from the plasma in the form of a reflected RF signal 708. The reflected RF signal 708 is transmitted through the RF connector 125 and split at point 122 into a reflected RF signal 124B and a reflected RF signal 522. The reflected RF signal 124B is processed in the same manner by the first capacitor 110 and the first filter 106 as described above with reference to Figure 1, and the reflected RF signal 522 is processed in the same manner as above by the branch circuit 503 (Figure 5A), or 533 (Figure 5B), or 573 (Figure 5C) to output a modified RF signal 710. The modified RF signal 710 is one example of any of the RF signals 534 (Figure 5A), 556 (Figure 5B), and 532 (Figure 5C).

[0153] In one embodiment, the HF source RFG404 is turned on to generate an RF signal 422 for a predetermined time, while the LFMPS102 remains off. If plasma is ignited or struck in the plasma chamber within the predetermined time, the LFMPS102 is turned on to generate an RF signal 116A. When the LFMPS102 is turned on, the HF source RFG404 is either turned off or remains on.

[0154] In one embodiment, the LFMPS102 is turned on to generate the RF signal 116A for a predetermined time, and the HF source RFG404 is turned on to generate the RF signal 422 for a predetermined time. If the plasma is ignited or struck in the plasma chamber within the predetermined time, the HF source RFG404 is either turned off or remains on.

[0155] In one embodiment, the matching unit 702 is coupled to point 122 via an RF connection.

[0156] Figure 7B is a diagram of one embodiment of a system 750 having an HFMPS 104 to illustrate the use of an LF source RFG 402. The system 750 includes an LF source RFG 402, a matching circuit 752, an HFMPS 104, a second filter 108, a second capacitor 112, and an RF coil 114. As an example, referring to Figure 5A, the matching circuit 752 includes branch circuit 501 but does not include branch circuit 503. As another example, referring to Figure 5B, the matching circuit 752 includes branch circuit 531 but does not include branch circuit 533. As yet another example, referring to Figure 5C, the matching circuit 752 includes branch circuit 571 but does not include branch circuit 573.

[0157] The LF source RFG402 is coupled to a matching unit 752, which is coupled to point 122. Upon receiving an RF signal 420 at its input, the matching unit 752 corrects the impedance of the RF signal 420 and outputs a corrected RF signal 754. For example, the matching unit 752 matches the impedance of a load coupled to the output of the matching unit 752 with the impedance of a source coupled to the input of the matching unit 752 and outputs a corrected RF signal 754. An example of a load coupled to the output of the matching unit 752 is a plasma chamber having an RF coil 114. Another example of a load coupled to the output of the matching unit 752 is an RF connection between the output and point 122, another RF connection between point 122 and the RF coil 114, and a plasma chamber including the RF coil 114. An example of a source coupled to the input of the matching unit 752 is the LF source RFG402 and an RF cable 408. The modified RF signal 754 and the output RF signal 120B are combined by adding them together at point 122 to generate a combined RF signal 756, which is then supplied to the RF coil 114 via the RF connection unit 125.

[0158] Plasma is generated or maintained within the plasma chamber when one or more process gases are supplied to the plasma chamber in addition to the combined RF signal 756. As the plasma is generated or maintained, RF power is reflected from the plasma in the form of a reflected RF signal 758. The reflected RF signal 758 is propagated through the RF connector 125 and split at point 122 into a reflected RF signal 124A and a reflected RF signal 520. The reflected RF signal 124A is processed in the same manner by the second capacitor 112 and the second filter 108 as described above with reference to Figure 1, and the reflected RF signal 520 is processed in the same manner as above by the branch circuit 501 (Figure 5A), or 531 (Figure 5B), or 571 (Figure 5C) to output a modified RF signal 760. The modified RF signal 760 is one example of any of the RF signals 528 (Figure 5A), 554 (Figure 5B), and 526 (Figure 5C).

[0159] In one embodiment, HFMPS104 is turned on to generate RF signal 116B for a predetermined time, while LF source RFG402 remains off. If plasma is ignited or struck in the plasma chamber within the predetermined time, LF source RFG402 is turned on to generate RF signal 420. When LF source RFG402 is turned on, HFMPS104 is either turned off or remains on.

[0160] In one embodiment, the LF source RFG402 is turned on to generate an RF signal 420 for a predetermined time, and the HFMPS104 is turned on to generate an RF signal 116B for a predetermined time. If the plasma is ignited or struck in the plasma chamber within the predetermined time, the HFMPS104 is either turned off or remains on.

[0161] In one embodiment, the matching unit 752 is coupled to point 122 via an RF connector.

[0162] Figure 8A is a diagram of one embodiment of system 800 having LF bias RFG302 and HF bias RFG304 to illustrate the use of LFMPS102 and HF source RFG404. System 800 includes LFMPS102, HF source RFG404, filter 106, first capacitor 110, matching unit 702, plasma chamber 308, LF bias RFG302, HF bias RFG304, and matching unit 306. Point 122 is the end of RF coil 312. 316 It is connected via the RF connection unit 125.

[0163] The combined RF signal 706 is supplied from point 122 to the RF coil 312 via the RF connector 125. The modified RF signal 334 is also supplied to the lower electrode 311, and when one or more process gases are supplied to the plasma chamber 308, plasma is generated or maintained within the plasma chamber 308. As the plasma is generated or maintained, the reflected RF signal 708 is reflected from the RF coil 312 to point 122 via the RF connector 125.

[0164] Figure 8B is a diagram of one embodiment of system 820 illustrating the use of LFMPS102 and HF source RFG404 when the lower electrode 311 is coupled to ground potential. System 820 includes LFMPS102, a first filter 106, a first capacitor 110, an HF source RFG404, a matching unit 702, and a plasma chamber 308. Plasma is generated or maintained in the plasma chamber 308 when a combined RF signal 706 is supplied to the RF coil 312, the lower electrode is coupled to ground potential, and one or more process gases are supplied to the plasma chamber 308. As the plasma is generated or maintained, the reflected RF signal 708 is reflected from the RF coil 312 through the RF connection 125 toward point 122.

[0165] Figure 8C shows one embodiment of system 840 having LF bias RFG302 and HF bias RFG304 to illustrate the use of LF source RFG402 and HFMPS104. System 840 includes LF source RFG402, matching unit 752, HFMPS104, second filter 108, second capacitor 112, plasma chamber 308, LF bias RFG302, HF bias RFG304, and matching unit 306. Point 122 is coupled to RF coil 312 via RF connector 125.

[0166] Plasma is generated or maintained in the plasma chamber 308 when the combined RF signal 756 is supplied to the plasma chamber 308 via the RF connector 125, along with the modified RF signal 334 and one or more process gases. Once the plasma is generated or maintained, a reflected RF signal 758 is generated and transmitted to point 122 via the RF connector 125.

[0167] Figure 8D is a diagram of one embodiment of system 860 illustrating the use of the LF source RFG402 and HFMPS104 when the lower electrode 311 is coupled to ground potential. System 860 includes the LF source RFG402, HFMPS104, matching unit 752, second filter 108, second capacitor 112, and plasma chamber 308.

[0168] A combined RF signal 756 is supplied to the plasma chamber 308 via the RF connector 125 in addition to one or more process gases, and when the lower electrode 311 is coupled to ground potential, plasma is generated or maintained within the plasma chamber 308. As the plasma is generated or maintained, the RF power of the reflected RF signal 758 is reflected towards point 122 via the RF connector 125.

[0169] Figure 9A shows the high frequency of multiple RF coils 114 and 904 This is a diagram of one embodiment of system 900 to illustrate a method of providing low and high frequencies to the RF coil 114. System 900 includes LFMPS 102, a first filter 106, a first capacitor 110, HFMPS 104, a second filter 108, a second capacitor 112, a signal divider 906, and the RF coil 114 and 904 The signal divider 906 includes a third capacitor 908 and a fourth capacitor 910. The RF coil 114 and 904 Both belong to the same plasma chamber, which will be discussed later.

[0170] The second capacitor 112 is coupled to capacitors 908 and 910 via a split point 912. For example, the second capacitor 112 is coupled to capacitors 908 and 910 via a split RF connector, such as a single RF strap split into two RF straps. In this example, a single RF strap is split at the split point 912. The third capacitor 908 is coupled to point 122, and the fourth capacitor 910 is coupled to terminal E3 of the RF coil 904. For example, the third capacitor 908 is coupled to point 122 via an RF connector, and the fourth capacitor 910 is coupled to terminal E3 via an RF connector. The opposite terminal E4 of the RF coil 904 is coupled to ground potential.

[0171] The second capacitor 112 receives the filtered signal 118B from the second filter 108 and balances the reactance of the second filter 108 with the combined reactance of the RF coils 114 and 904 to provide the output RF signal 901. For example, the second capacitor 112 has capacitance that achieves a first reactance of the second filter 108 and a second reactance which is the combined reactance of the RF coils 114 and 904. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude opposite to the direction of the second reactance. In this example, the capacitance of the second capacitor 112 results in a high-frequency resonant frequency of the HFMPS 104. In another example, the second capacitor 112 has capacitance that cancels out the reactance of the second filter 108 with respect to the combined reactance of the RF coils 114 and 904. In this example, the second capacitor 112 has capacitance that achieves the first reactance of the second filter 108 and a second reactance which is the combined reactance of the RF coils 114 and 904. In this example, the first reactance and the second reactance have the same amplitude and opposite direction. In this example, the capacitance of the second capacitor 112 results in a high-frequency resonant frequency for the HFMPS 102. As an example, the combined reactance of the RF coils 114 and 904 is the sum or combination of the reactance of RF coil 114 and the reactance of RF coil 904. The output RF signal 901 is provided from the second capacitor 112 to the splitting point 912.

[0172] The output RF signal 901 is split into output RF signal 914 and output RF signal 916 at the splitting point 912. For example, the output RF signal 901The RF power is divided into the RF power of output RF signal 914 and the RF power of output RF signal 916. The third capacitor 908 modifies the impedance of output RF signal 914 to provide output RF signal 918. For example, the third capacitor 908 balances the reactance of the second filter 108 with the reactance of the RF coil 114 to provide output RF signal 918. For example, the third capacitor 908 has capacitance to achieve the first reactance of the second filter 108 and the second reactance of the RF coil 114. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude in the opposite direction to the direction of the second reactance. In this example, the capacitance of the third capacitor 908 results in a high-frequency resonant frequency of HFMPS 104. As another example, the third capacitor 908 has a capacitance that cancels out the reactance of the second filter 108 with respect to the reactance of the RF coil 114. In this example, the third capacitor 908 has a capacitance that achieves the first reactance of the second filter 108 and the second reactance of the RF coil 114. In this example, the first reactance and the second reactance have the same amplitude and opposite directions. In this example, the capacitance of the third capacitor 908 results in a high-frequency resonant frequency for the HFMPS 104. The output RF signal 918 is supplied from the third capacitor 908 to point 122.

[0173] Furthermore, the fourth capacitor 910 modifies the impedance of the output RF signal 916 to provide the output RF signal 920. For example, the fourth capacitor 910 balances the reactance of the second filter 108 with the reactance of the RF coil 904 to provide the output RF signal 920. For example, the fourth capacitor 910 has capacitance that achieves a first reactance of the second filter 108 and a second reactance of the RF coil 904. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude opposite to the direction of the second reactance. In this example, the capacitance of the fourth capacitor 910 results in a high-frequency resonant frequency of the HFMPS 104. In another example, the fourth capacitor 910 has capacitance that cancels out the reactance of the second filter 108 with respect to the reactance of the RF coil 904. For example, the fourth capacitor 910 has a capacitance that achieves the first reactance of the second filter 108 and the second reactance of the RF coil 904. In this example, the first reactance has the same amplitude as the second reactance, but in opposite directions. In this example, the capacitance of the fourth capacitor 910 results in a high-frequency resonant frequency of the HFMPS 104. The output RF signal 920 is supplied from the fourth capacitor 910 to the RF coil 904.

[0174] Output RF signals 914, 916, 918, and 920 have high frequencies. Output RF signal 120A has a low frequency.

[0175] The output RF signal 918 is combined with the output RF signal 120A by being added together or otherwise, generating a combined RF signal 922 at point 122. The combined RF signal 922 has a combination of the high frequencies of the output RF signal 918 and the low frequencies of the output RF signal 120A. The combined RF signal 922 is transmitted to terminal E1 of the RF coil 114 via the RF connection 125. The output RF signal 920 is transmitted from the fourth capacitor 910 to terminal E3 of the RF coil 904.

[0176] Plasma is generated or maintained within the plasma chamber when the combined RF signal 922 is supplied to the RF coil 114 and the output RF signal 920 is supplied to the RF coil 904. While the plasma is generated or maintained within the plasma chamber, RF power is reflected from the plasma chamber in the form of a reflected RF signal 924. The reflected RF signal 924 is transmitted to point 122 via the RF coil 114, terminal E1, and RF connector 125. 924 This is split into reflected RF signal 124B and reflected RF signal 926. Reflected RF signal 124B is supplied from point 122 to the first capacitor 110. Reflected RF signal 926 is supplied from point 122 to the third capacitor 908.

[0177] The third capacitor 908 modifies the impedance of the reflected RF signal 926 and provides the RF signal 928 to the capacitor 112. For example, the third capacitor 908 receives the RF signal 928 and provides the RF signal 928 by balancing the reactances of the second filter 108 and the RF coil 904 in the same manner as described above. For example, the third capacitor 908 provides the RF signal 928 by reducing the impedance of the reflected RF signal 926 to a minimum amount, such as zero or near zero.

[0178] Furthermore, when plasma is generated or maintained within the plasma chamber, RF power is reflected from the plasma chamber in the form of a reflected RF signal 930. The reflected RF signal 930 is transmitted to a fourth capacitor 910 via the RF coil 904 and terminal E3. The fourth capacitor 910 modifies the impedance of the reflected RF signal 930 and outputs an RF signal 932 at its input. For example, the fourth capacitor 910 reduces the impedance of the reflected RF signal 930 to a minimum amount, such as zero or near zero, to provide the RF signal 932. RF signals 928 and 932 are combined at the splitting point 912 to generate a reflected RF signal 124A. The reflected RF signal 124A is reflected from the splitting point 912 toward the second capacitor 112.

[0179] In one embodiment, the second capacitor 112 is coupled to the splitting point 912 via an RF connector, and the splitting point 912 is coupled to the third capacitor 908 via another RF connector. The splitting point 912 is also coupled to the capacitor bank 910 via an RF connector. Furthermore, the third capacitor 908 is coupled to point 122 via an RF connector, and the fourth capacitor 910 is coupled to terminal E3 via an RF connector. In this embodiment, the RF signal 124A and 901 RF signals 914 and 928 are transmitted between the second capacitor 112 and the dividing point 912 via the RF connection between the second capacitor 112 and the dividing point 912. RF signals 916 and 932 are transmitted between the dividing point 912 and the fourth capacitor 910 via the RF connection between the dividing point 912 and the fourth capacitor 910. RF signals 918 and 926 are transmitted between the third capacitor 908 and point 122 via the RF connection between the third capacitor 908 and point 122. RF signals 920 and 930 are transmitted between the fourth capacitor 910 and terminal E3 via the RF connection between the fourth capacitor 910 and terminal E3.

[0180] Figure 9B shows multiple RF coils 114 and low frequencies. 904 This is a diagram of one embodiment of system 950 to illustrate a method of providing low and high frequencies to the RF coil 904. System 950 includes LFMPS 102, a first filter 106, a first capacitor 110, HFMPS 104, a second filter 108, a second capacitor 112, a signal divider 952, and the RF coil 114 and 904 The signal divider 952 includes a third capacitor 954 and a fourth capacitor 956.

[0181] The first capacitor 110 is coupled to capacitors 954 and 956 via a split point 958. For example, the first capacitor 110 is coupled to capacitors 954 and 956 via a split RF connector, such as a single RF strap split into two RF straps. In this example, a single RF strap is split at the split point 958. The fourth capacitor 956 is coupled to point 960, and the third capacitor 954 is coupled to terminal E1 of the RF coil 114. For example, the fourth capacitor 956 is coupled to point 960 via an RF connector, and the third capacitor 954 is coupled to terminal E1 via an RF connector. Also, the second capacitor 112 is coupled to point 960. Point 960 is coupled to terminal E3 of the RF coil 904 via an RF connector 972.

[0182] The first capacitor 110 receives the filtered signal 118A and balances the reactance of the first filter 106 with the combined reactance of the RF coils 114 and 904 to provide the output RF signal 951. For example, the first capacitor 110 has capacitance that achieves a first reactance of the first filter 106 and a second reactance which is the combined reactance of the RF coils 114 and 904. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude opposite to the direction of the second reactance. In this example, the capacitance of the first capacitor 110 lowers the low-frequency resonant frequency of the LFMPS 102. In another example, the first capacitor 110 has capacitance that cancels out the reactance of the first filter 106 with respect to the combined reactance of the RF coils 114 and 904. For example, the first capacitor 110 has a capacitance that achieves a first reactance of the first filter 106 and a second reactance which is the combined reactance of the RF coils 114 and 904. In this example, the first reactance has the same amplitude as the second reactance but in opposite directions. In this example, the capacitance of the first capacitor 110 lowers the low-frequency resonant frequency of the LFMPS 102. The output RF signal 951 is supplied from the first capacitor 110 to point 958.

[0183] The output RF signal 951 is split at point 958 into output RF signal 962 and output RF signal 964. The third capacitor 954 modifies the impedance of output RF signal 962 to provide output RF signal 966. For example, the third capacitor 954 balances the reactance of the first filter 106 with the reactance of the RF coil 114 to provide output RF signal 966. For example, the third capacitor 954 has capacitance to achieve a first reactance of the first filter 106 and a second reactance of the RF coil 114. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude in the opposite direction to the direction of the second reactance. 954 Due to the capacitance, the low-frequency resonant frequency of the LFMPS102 is low. As another example, the third capacitor 954 has a capacitance that cancels out the reactance of the first filter 106 with respect to the reactance of the RF coil 114. For example, the third capacitor 954 has a capacitance that achieves the first reactance of the first filter 106 and the second reactance of the RF coil 114. In this example, the first reactance and the second reactance have equal amplitude and opposite direction. In this example, the capacitance of the third capacitor 954 lowers the low-frequency resonant frequency of the LFMPS102. The output RF signal 966 is supplied from the third capacitor 954 to the RF coil 114.

[0184] Furthermore, the fourth capacitor 956 modifies the impedance of the output RF signal 964 to provide the output RF signal 968. For example, the fourth capacitor 956 balances the reactance of the first filter 106 with the reactance of the RF coil 114 to provide the output RF signal 968. For example, the fourth capacitor 956 has capacitance to achieve a first reactance of the first filter 106 and a second reactance of the RF coil 114. In this example, the first reactance is within a predetermined range from the amplitude of the second reactance and has an amplitude opposite to the direction of the second reactance. In this example, the capacitance of the fourth capacitor 956 lowers the low-frequency resonant frequency of the LFMPS 102. In another example, the fourth capacitor 956 is the RF coil 904 The fourth capacitor 956 has a capacitance that cancels out the reactance of the first filter 106 with respect to the reactance of the RF coil. For example, the fourth capacitor 956 cancels out the reactance of the first filter 106 with respect to the first reactance of the RF coil. 904 The capacitor has a capacitance that achieves a second reactance. In this example, the first reactance has the same amplitude as the second reactance but in the opposite direction. In this example, the capacitance of the fourth capacitor 956 lowers the low-frequency resonant frequency of the LFMPS 102. The output RF signal 968 is supplied from the fourth capacitor 956 to point 960.

[0185] Output RF signals 962, 964, 966, and 968 have low frequencies. Output RF signal 120B has a high frequency.

[0186] The output RF signal 968 is combined with the output RF signal 120B by being added together or otherwise, generating a combined RF signal 970 at point 960. The combined RF signal 970 has a combination of the low frequency of the output RF signal 968 and the high frequency of the output RF signal 120B. The combined RF signal 970 is transmitted to terminal E3 of the RF coil 904 via the RF connector 972. The output RF signal 966 is transmitted from the third capacitor 954 to terminal E1 of the RF coil 114.

[0187] Plasma is generated or maintained within a plasma chamber containing RF coils 114 and 904 when a combined RF signal 970 is supplied to RF coil 904 and an output RF signal 966 is supplied to RF coil 114. As plasma is generated or maintained within the plasma chamber, RF power is reflected from the plasma chamber in the form of a reflected RF signal 974. The reflected RF signal 974 is transmitted to point 960 via RF coil 904, terminal E3, and RF connector 972. At point 960, the reflected RF signal 974 is split into reflected RF signal 124A and reflected RF signal 976. Reflected RF signal 124A is supplied from point 960 to a second capacitor 112. Reflected RF signal 976 is supplied from point 960 to a fourth capacitor 956. The fourth capacitor 956 modifies the impedance of the reflected RF signal 976 to provide RF signal 978 at its input. For example, the fourth capacitor 956 balances the reactance between the first filter 106 and the RF coil 904 in the same manner as described above, and provides the RF signal 978 to the splitting point 958. For example, the fourth capacitor 956 reduces the impedance of the reflected RF signal 976 to a minimum, such as zero or near zero, and outputs the RF signal 978 to the splitting point 958.

[0188] Furthermore, when plasma is generated or maintained within the plasma chamber, RF power is reflected from the plasma chamber in the form of a reflected RF signal 980. The reflected RF signal 980 is transmitted to a third capacitor 954 via the RF coil 114 and terminal E1. The third capacitor 954 modifies the impedance of the reflected RF signal 980 and outputs an RF signal 982 at its input. For example, the third capacitor 954 balances the reactance between the first filter 106 and the RF coil 114 in the same manner as described above, providing the RF signal 982 to the splitting point 958. Exemplarily, the third capacitor 954 reduces the impedance of the reflected RF signal 980 to a minimum, such as zero or near zero, and outputs the RF signal 982 to the splitting point 958. RF signals 982 and 978 are combined at the splitting point 958 to generate a reflected RF signal 124B. The reflected RF signal 124B is reflected from the splitting point 958 towards the first capacitor 110.

[0189] In one embodiment, the first capacitor 110 is coupled to the splitting point 958 via an RF connector. The splitting point 958 is coupled to the third capacitor 954 via an RF connector, and the splitting point 958 is coupled to the fourth capacitor 956 via an RF connector. Furthermore, the third capacitor 954 is coupled to terminal E1 via an RF connector, and the fourth capacitor 956 is coupled to point 960 via an RF connector. Also, the second capacitor 112 is coupled to point 960 via an RF connector. In this embodiment, RF signals 951 and 124B are transmitted between the first capacitor 110 and the splitting point 958 via an RF connector between the first capacitor 110 and the splitting point 958. Furthermore, RF signals 962 and 982 are transmitted between the splitting point 958 and the third capacitor 954 via an RF connector between the splitting point 958 and the third capacitor 954. Furthermore, RF signals 966 and 980 are transmitted between the third capacitor 954 and terminal E1 via the RF connection between the third capacitor 954 and terminal E1. Also, RF signals 964 and 978 are transmitted between the division point 958 and the fourth capacitor 956 via the RF connection between the division point 958 and the fourth capacitor 956. In addition, RF signals 968 and 976 are transmitted between the fourth capacitor 956 and point 960 via the RF connection between the fourth capacitor 956 and point 960. Furthermore, RF signals 120B and 124A are transmitted between point 960 and the second capacitor 112 via the RF connection between point 960 and the second capacitor 112.

[0190] Figure 9C is a diagram of one embodiment of the plasma system 980 illustrating a method for filtering low frequencies so that they are not applied to the RF coil 904. The plasma system 980 is structurally and functionally the same as the plasma system 900 (Figure 9A), except that a filter 983 is used. Examples of filters 983 include a high-pass filter 230 (Figure 2B), a band-pass filter 250 (Figure 2C), and a band-pass filter 270 (Figure 2D).

[0191] The filter 983 is coupled between the capacitor 910 and the RF coil 904. For example, one end of the filter 983 is coupled to the capacitor 910, and the other end of the filter 983 is coupled to end E3 of the RF coil 904.

[0192] If the output signal 920 contains low frequencies, the filter 983 receives the output RF signal 920 from the capacitor 910, filters out the low frequencies, and outputs the filtered signal 984. For example, when the filter 983 receives the signal from the LFMPS 102 via the filter 106, capacitor 110, point 122, capacitor 908, split point 912, and capacitor 910, the low frequencies are embedded in the output signal 920. The filtered signal 984 is then supplied to the RF coil 904. In this manner, the RF coil 904 is not damaged by the low frequencies.

[0193] Plasma is generated in the plasma chamber containing RF coils 114 and 904 when the combined RF signal 922 is supplied to RF coil 114 and the filtered signal 984 is supplied to RF coil 904. As the plasma is generated, the RF power from the plasma is reflected to filter 983 in the form of a reflected RF signal 986. Filter 983 passes the high frequencies of the reflected RF signal 986 and filters out the low frequencies of the reflected RF signal 986 to output a reflected RF signal 930. The reflected RF signal 930 is transmitted from filter 983 to capacitor 910.

[0194] Figure 9D is a diagram of one embodiment of the plasma system 990 illustrating a method for filtering out high frequencies so that they are not applied to the RF coil 114. The plasma system 990 is structurally and functionally identical to the plasma system 950 (Figure 9B), except that a filter 992 is used. Examples of the filter 992 include a low-pass filter 200 (Figure 2A), a band-pass filter 250 (Figure 2C), and a band-pass filter 270 (Figure 2D).

[0195] The filter 992 is coupled between the capacitor 954 and the RF coil 114. For example, one end of the filter 992 is coupled to the capacitor 954, and the other end of the filter 992 is coupled to end E1 of the RF coil 114.

[0196] If the output RF signal 966 contains high frequencies, the filter 992 receives the output RF signal 966 from the capacitor 954, filters out the high frequencies, and outputs the filtered signal 994. For example, when the filter 992 receives the HFMPS 104 through the second filter 108, the second capacitor 112, point 960, capacitor 956, split point 958, and capacitor 954, the high frequencies are embedded in the output RF signal 966. The filtered signal 994 is then supplied to the RF coil 114. In this method, the RF coil 114 is not damaged by the high frequencies.

[0197] Plasma is generated in a plasma chamber containing RF coils 114 and 904 when the combined RF signal 970 is supplied to RF coil 904 and the filtered signal 994 is supplied to RF coil 114. As the plasma is generated, the RF power from the plasma is reflected to filter 992 in the form of a reflected RF signal 996. Filter 992 passes the low frequencies of the reflected RF signal 996 and filters out the high frequencies of the reflected RF signal 996 to output a reflected RF signal 980. The reflected RF signal 980 is transmitted from filter 992 to capacitor 954.

[0198] Figure 10A is a diagram of one embodiment of the plasma system 1000 to illustrate the use of a signal divider 906 within the plasma system 1000. The plasma system 1000 includes an LFMPS 102, a first filter 106, a first capacitor 110, an HFMPS 104, a second filter 108, a second capacitor 112, a signal divider 906, an LF bias RFG 302, an HF bias RFG 304, a matching unit 306, and a plasma chamber 1002. The plasma chamber 1002 is structurally identical to the plasma chamber 308 (Figure 3A), except that the plasma chamber 1002 includes an RF coil 1004.

[0199] RF coil 1004 is located around RF coil 312. For example, RF coil 1004 surrounds RF coil 312 and is positioned in the same horizontal plane as RF coil 312. RF coil 1004 is an example of RF coil 904 (Figure 9A). Capacitor 910 is coupled to terminal E3 of RF coil 1004.

[0200] A combined RF signal 922 is supplied to the RF coil 312, an output RF signal 920 is supplied to the RF coil 1004, and a modified RF signal 334 is supplied to the lower electrode 311. Plasma is generated in the plasma chamber 1002 when one or more process gases are supplied to the plasma chamber 1002. The RF power of the plasma is reflected in the form of reflected RF signals 930 and 924.

[0201] In one embodiment, the RF coil 1004 is an RF coil 312 It is positioned on a horizontal plane different from the horizontal plane on which it is placed.

[0202] Figure 10B shows a plasma system having a plasma chamber 1002 with a lower electrode 311 coupled to ground potential, illustrating the use of a signal divider 906. 1030 This is a diagram of one embodiment of a plasma system. 1030This includes LFMPS102, a first filter 106, a first capacitor 110, HFMPS104, a second filter 108, a second capacitor 112, a signal divider 906, and a plasma chamber 1002.

[0203] A combined RF signal 922 is supplied to the RF coil 312, and an output RF signal 920 is supplied to the RF coil 1004. When the lower electrode 311 is coupled to ground potential and one or more process gases are supplied to the plasma chamber 1002, plasma is generated within the plasma chamber 1002. The RF power of the plasma is reflected in the form of reflected RF signals 930 and 924.

[0204] Figure 10C is a diagram of one embodiment of plasma system 1040 to illustrate the use of a signal divider in plasma system 1040. Plasma system 1040 includes LFMPS 102, a first filter 106, a first capacitor 110, HFMPS 104, a second filter 108, a second capacitor 112, a signal divider 952, an LF bias RFG 302, an HF bias RFG 304, a matching unit 306, and a plasma chamber 1002. Point 960 is coupled to terminal E3 of RF coil 1004.

[0205] A combined RF signal 970 is supplied to the RF coil 1004, an output RF signal 966 is supplied to the RF coil 312, and a modified RF signal 334 is supplied to the lower electrode 311. Plasma is generated in the plasma chamber 1002 when one or more process gases are supplied to the plasma chamber 1002. The RF power of the plasma is reflected in the form of reflected RF signals 974 and 980.

[0206] Figure 10D illustrates one embodiment of a plasma system 1050 having a plasma chamber 1002 with a lower electrode 311 coupled to ground potential, illustrating the use of a signal divider 952. The plasma system 1050 includes an LFMPS 102, a first filter 106, a first capacitor 110, an HFMPS 104, a second filter 108, a second capacitor 112, a signal divider 952, and a plasma chamber 1002.

[0207] A combined RF signal 970 is supplied to the RF coil 1004, and an output RF signal 966 is supplied to the RF coil 312. The lower electrode 311 is coupled to ground potential, and when one or more process gases are supplied to the plasma chamber 1002, plasma is generated within the plasma chamber 1002. The RF power of the plasma is reflected in the form of reflected RF signals 974 and 980.

[0208] Figure 11A is an embodiment of graph 1100 illustrating the clock signal 1102. Graph 1100 plots the logic level of the clock signal 1102 against time t. The clock signal 1102 periodically transitions between logic level 1 and logic level 0. For example, during cycle 1 of the clock signal 1102, at time t0, the clock signal 1102 transitions from logic level 0 to logic level 1. During cycle 1, the clock signal 1102 remains at logic level 1 from time t0 to time t8. Furthermore, during cycle 1, at time t8, the clock signal 1102 transitions from logic level 1 to logic level 0. The clock signal 1102 remains at logic level 0 from time t8 to time t16. During cycle 2 of the clock signal 1102, at time t16, the clock signal 1102 transitions from logic level 0 to logic level 1. Cycle 2 is continuous with cycle 1. During cycle 2, the clock signal 1102 remains at logic level 1 from time t16 to time t24. Furthermore, cycle 2During this time, at time t24, the clock signal 1102 transitions from logic level 1 to logic level 0. The clock signal 1102 remains at logic level 0 from time t24 to time t32. In this way, the logic levels 0 and 1 of the clock signal 1102 are periodically repeated during additional cycles of the clock signal 1102.

[0209] Figure 11B is an embodiment of graph 1104 illustrating parameters such as power or voltage of an RF signal 1106 generated by LFMPS102 (Figure 1), LF bias RFG302 (Figure 3A), or LF source RFG402 (Figure 4). RF signal 1106 is an example of RF signal 116A (Figure 1), RF signal 330 (Figure 3A), or RF signal 420 (Figure 4). RF signal 1106 is a continuous wave (CW) signal, such as a sine wave signal, and has peak-to-peak parameter levels of PR2 and -PR2, or zero-to-peak amplitude of PR2. For example, RF signal 1106 oscillates periodically between parameter levels PR2 and -PR2 during each clock cycle of clock signal 1102. Parameter level PR2 is greater than parameter level PR0, and parameter level PR0 is greater than parameter level -PR2.

[0210] Figure 11C is an embodiment of graph 1108 illustrating the parameters of an RF signal 1110 generated by HFMPS104 (Figure 1), HF bias RFG304 (Figure 3A), or HF source RFG404 (Figure 4). In graph 1108, the parameters of RF signal 1110 are plotted on the Y axis, and time t is plotted on the X axis. RF signal 1110 is an example of RF signal 116B (Figure 1), RF signal 332 (Figure 3A), or RF signal 422 (Figure 4). RF signal 1110 is a continuous wave signal and has peak-to-peak parameter levels of PRb and -PRb, or zero-to-peak amplitude of PRb. For example, RF signal 1110 oscillates periodically between parameter levels PRb and -PRb during each clock cycle of clock signal 1102. Parameter level PRb is greater than parameter level PR0, and parameter level PR0 is greater than parameter level -PRb. For example, parameter level PRb is lower than parameter level PR2, and parameter level -PRb is higher than parameter level -PR2. Another example is parameter level PR2 is lower than parameter level PRb, and parameter level -PR2 is higher than parameter level -PRb.

[0211] Furthermore, the oscillation frequency of RF signal 1110 is higher than the oscillation frequency of RF signal 1106. Therefore, RF signal 1110 has a higher frequency than RF signal 1106.

[0212] Figure 11D is an embodiment of graph 1112 illustrating the pulse output of RF signal 1114 between parameter levels PR2 and -PR2 and parameter levels PR1 and -PR1. In graph 1112, the parameters of RF signal 1114 are plotted on the Y axis and time t is plotted on the X axis. Parameter levels PR2 and -PR2 represent parameter state S1 of RF signal 1114. Parameter levels PR1 and -PR1 represent parameter state S2 of RF signal 1114. Parameter level PR1 is lower than parameter level PR2 and higher than parameter level PR0. Similarly, parameter level -PR1 is higher than parameter level -PR2 and lower than parameter level PR0. RF signal 1114 is an example of RF signal 116A (Figure 1), RF signal 330 (Figure 3A), or RF signal 420 (Figure 4).

[0213] During cycle 1 of the clock signal 1102, at time t0, the parameters of the RF signal 1114 are pulsed, transitioning from parameter level PR1 to parameter level PR2, and from parameter level -PR1 to parameter level -PR2. The RF signal 1114 oscillates between parameter levels PR2 and -PR2 from time t0 to time t8. Furthermore, the peak-to-peak parameter levels of the RF signal 1114 from time t0 to time t8 are PR2 and -PR2.

[0214] Furthermore, during cycle 1 of the clock signal 1102, at time t8, the parameters of the RF signal 1114 are pulsed from parameter level PR2 to parameter level PR1, and from parameter level -PR2 to parameter level -PR1. The RF signal 1114 oscillates between parameter levels PR1 and -PR1 from time t8 to time t16. Also, the peak-to-peak of the RF signal 1114 from time t8 to time t16... no pa The parameter levels are PR1 and -PR1. Similarly, parameter levels PR2 and -PR2, and parameter levels PR1 and -PR1 are repeated during cycle 2 of the clock signal 1102.

[0215] Figure 11E is an embodiment of Graph 1116 illustrating the pulse output of RF signal 1118 between parameter levels PRb and PRa, and between parameter levels -PRb and -PRa. In Graph 1116, the parameters of RF signal 1118 are plotted on the Y axis and time t is plotted on the X axis. Parameter levels PRb and -PRb represent parameter state S1 of RF signal 1118. Parameter levels PRa and -PRa represent parameter state S2 of RF signal 1118. Parameter level PRa is lower than parameter level PRb and higher than parameter level PR0. Similarly, parameter level -PRa is higher than parameter level -PRb and lower than parameter level PR0. RF signal 1118 is an example of RF signal 116B (Figure 1), RF signal 332 (Figure 3A), or RF signal 422 (Figure 4).

[0216] During cycle 1 of the clock signal 1102, at time t0, the parameters of the RF signal 1118 are pulsed from parameter level PRa to parameter level PRb, and from parameter level -PRa to parameter level -PRb. The RF signal 1118 oscillates between parameter levels PRb and -PRb from time t0 to time t8.

[0217] Furthermore, during cycle 1 of clock signal 1102, at time t8, the parameters of RF signal 1118 are pulsed from parameter level PRb to parameter level PRa, and from parameter level -PRb to parameter level -PRa. RF signal 1118 oscillates between parameter levels PRa and -PRa from time t8 to time t16. Also, the peak-to-peak parameter levels of RF signal 1118 from time t8 to time t16 are PRa and -PRa. In a similar manner, parameter levels PRb and -PRb, and parameter levels PRa and -PRa are repeated during cycle 2 of clock signal 1102. Note that the oscillation frequency of RF signal 1118 is higher than the oscillation frequency of RF signal 1114.

[0218] Figure 11F is an embodiment of graph 1112 of the RF signal 1114.

[0219] Figure 11G is an embodiment of graph 1120 illustrating the pulse output of RF signal 1122, which is out of phase with the pulse output of RF signal 1114 (Figure 11F). In graph 1120, the parameters of RF signal 1122 are plotted against time t. RF signal 1122 is an example of RF signal 116B (Figure 1), RF signal 332 (Figure 3A), or RF signal 422 (Figure 4).

[0220] During cycle 1 of clock signal 1102, from time t0 to time t2, the parameters of RF signal 1122 are pulsed between parameter levels PRa and -PRa. Furthermore, during cycle 1 of clock signal 1102, at time t2, the parameters of RF signal 1122 are pulsed from parameter level PRa to parameter level PRb, and from parameter level -PRa to parameter level -PRb. Parameter levels PRa and -PRa represent the parameter state S1 of RF signal 1122. Parameter levels PRb and -PRb represent the parameter state S2 of RF signal 1122. Time t2 occurs after time t0. During cycle 1 of clock signal 1102, from time t2 to time t10, the parameters of RF signal 1122 are pulsed between parameter levels PRb and -PRb. Time t10 occurs after time t8.

[0221] Furthermore, during cycle 1 of clock signal 1102, at time t10, the parameters of RF signal 1122 are pulsed from parameter level PRb to parameter level PRa, and from parameter level -PRb to parameter level -PRa. RF signal 1122 oscillates between parameter levels PRa and -PRa from time t10 to time t16. In a similar manner, parameter levels PRa and -PRa, and parameter levels PRb and -PRb are repeated during cycle 2 of clock signal 1102. Note that the oscillation frequency of RF signal 1122 is higher than the oscillation frequency of RF signal 1114.

[0222] The parameter levels PRb and PRa of RF signal 1122 are pulsed out at a phase difference from the pulse outputs of parameter levels PR2 and PR1 of RF signal 1114, and the parameter levels -PRb and -PRa of RF signal 1122 are pulsed out at a phase difference from the parameter levels -PR2 and -PR1 of RF signal 1114. For example, during cycle 1 of clock signal 1102 (Figure 11A), the parameter of RF signal 1122 transitions from parameter level PRa to parameter level PRb at time t2, rather than transitioning from parameter level PRa to parameter level PRb at time t0. For another example, during cycle 1 of clock signal 1102 (Figure 11A), the parameter of RF signal 1122 transitions from parameter level PRb to parameter level PRa at time t10, rather than transitioning from parameter level PRb to parameter level PRa at time t8. As yet another example, during cycle 2 of clock signal 1102, the parameter of RF signal 1122 transitions from parameter level PRa to parameter level PRb at time t18, rather than transitioning from parameter level PRa to parameter level PRb at time t16. Time t18 occurs after time t16.

[0223] In one embodiment, the parameters of the RF signal transition from parameter level PRb to parameter level PRa at time t6, not time t10, similar to RF signal 1122. Time t6 occurs before time t8. Also, the parameters of the RF signal transition from parameter level PRa to parameter level PRb at time t14, not time t18. Time t14 occurs before time t16.

[0224] Figure 11H is an embodiment of the RF signal 1114 shown in graph 1112.

[0225] Figure 11I is an embodiment of Graph 1124 illustrating that the pulse output frequency of the parameters of RF signal 1114 (Figure 11F) is lower than the pulse output frequency of the parameters of RF signal 1126. Graph 1124 plots the parameters of RF signal 1126 against time t. RF signal 1126 is an example of RF signal 116B (Figure 1), RF signal 332 (Figure 3A), or RF signal 422 (Figure 4).

[0226] During cycle 1 of the clock signal 1102, at time t0, the parameters of the RF signal 1126 are pulsed from parameter level PRa to parameter level PRb, and from parameter level -PRa to parameter level -PRb. Parameter levels PRb and -PRb represent parameter state S1 of the RF signal 1126. Also, parameter levels PRa and -PRa represent parameter state S2 of the RF signal 1126. The parameter levels of the RF signal 1126 from time t0 to time t16 are PRb and -PRb. For example, the RF signal 1126 oscillates between parameter levels PRb and -PRb from time t0 to time t16.

[0227] Furthermore, during cycle 2 of clock signal 1102, at time t16, the parameters of RF signal 1126 are pulsed from parameter level PRb to parameter level PRa, and from parameter level -PRb to parameter level -PRa. During cycle 2 of clock signal 1102, the parameter levels of RF signal 1126 from time t16 to time t32 are PRa and -PRa. For example, RF signal 1126 oscillates between parameter levels PRa and -PRa from time t16 to time t32. Time t32 occurs after time t16. In a similar manner, parameter levels PRa and -PRa, and parameter levels PRb and -PRb are repeated during cycle 3 of clock signal 1102. Cycle 3 is continuous with cycle 2 of clock signal 1102. Note that the oscillation frequency of RF signal 1126 is higher than the oscillation frequency of RF signal 1114.

[0228] The parameter levels PR2, -PR2, PR1, and -PR1 of RF signal 1114 have a higher pulse output frequency than the parameter levels PRb, -PRb, PRa, and -PRa of RF signal 1126. For example, during cycle 1 of clock signal 1102 (Figure 11A), the parameters of RF signal 1114 are pulsed twice, and the parameter level of RF signal 1126 is pulsed once. For example, during cycle 1 of clock signal 1102, the parameters of RF signal 1114 are pulsed at time t0 for the first pulse and at time t8 for the second pulse. In this example, during cycle 1 of clock signal 1102, the parameters of RF signal 1126 are pulsed once at time t0. In this way, during each cycle of clock signal 1102, the parameters of RF signal 1114 are pulsed at a higher pulse output frequency than the parameters of RF signal 1126.

[0229] Furthermore, the duty cycle of the pulse output parameter of RF signal 1114 is different from the duty cycle of the pulse output parameter of RF signal 1126. For example, the duty cycle of the pulse output parameter of RF signal 1114 is 50%, and the duty cycle of the pulse output parameter of RF signal 1126 is 100%. For example, the parameter level of RF signal 1114 is PR2 for half the duration of each clock cycle of clock signal 1102 (Figure 11A). In this example, the parameter level of RF signal 1126 is PRb for the entire duration of each clock cycle of clock signal 1102.

[0230] In one embodiment, the pulse output frequency of a parameter of another RF signal similar to RF signal 1126 is greater than the pulse output frequency of a parameter of RF signal 1114. For example, during each cycle of clock signal 1102, the parameter of the other RF signal is pulsed three times. For example, the parameter of the other RF signal is pulsed from parameter level PRa to parameter level PRb at time t0, from parameter level PRb to parameter level PRa at time t4, and from parameter level PRa to parameter level PRb at time t8. Time t4 occurs after time t0 and before time t8.

[0231] Furthermore, the pulse output of the RF signal parameters between a pair of positive parameter levels (e.g., PRa to PRb, or vice versa) occurs synchronously with the pulse output of the RF signal parameters between a pair of negative parameter levels (e.g., -PRa to -PRb, or vice versa). For example, the parameters of RF signal 1114 transition from parameter level PR1 to parameter level PR2 at time t0. In this example, the parameters of RF signal 1114 transition simultaneously from parameter level -PR1 to parameter level -PR2 at time t0. As another example, the parameters of RF signal 1114 transition from parameter level PR2 to parameter level PR1 at time t8. In this example, the parameters of RF signal 1114 transition simultaneously from parameter level -PR2 to parameter level -PR1 at time t8.

[0232] Figure 12A-1 is a diagram of one embodiment of system 1200 to illustrate the details of MPS1202. MPS1202 is an example of either LFMPS102 or HFMPS104 (Figure 1). System 1200 includes MPS1202 and host computer 1204. Host computer 1204 includes processor 1206 and memory device 1208. Processor 1206 is coupled to memory device 1208. Examples of processors used herein include application-specific integrated circuits (ASICs), programmable logic devices (PLDs), microprocessors, microcontrollers, and central processing units (CPUs). Examples of memory devices used include random access memory (RAM) and read-only memory (ROM). For example, the memory device may be flash memory or a redundant array (RAID) of independent disks.

[0233] The MPS1202 includes an input section 1210, an output section 1212, and a reactance circuit 1214. Examples of the input section 1210 include a signal generator and part of a gate driver. An example of a signal generator is a square wave oscillator that generates a square wave signal such as a digital waveform or pulse train. The square wave signal may be referred to as a square waveform in this specification. The square waveform is pulsed between a first logic level (e.g., high or 1) and a second logic level (e.g., low or zero). Examples of the output section 1212 include the remainder of a gate driver and a half-bridge transistor circuit. Furthermore, an example of the reactance circuit 1214 is a variable capacitor. Another example of the reactance circuit 1214 is a fixed capacitor.

[0234] The input section 1210 is coupled to the output section 1212, and the output section 1212 is coupled to the reactance circuit 1214. The reactance circuit 1214 is coupled to the filter 1218 via the RF connection section 1510. Filter 1218 is an example of either filter 106 or 108 (Figure 1). For example, if MPS1202 is an example of LFMPS102, then filter 1218 is an example of the first filter 106. In this example, MPS1202 is H In the case of an example of FMPS104, filter 1218 is an example of a second filter 108. Processor 1206 is coupled to input 1210 via transfer cable 1226. Examples of transfer cables used herein include cables that transfer data via serial, parallel, or Universal Serial Bus (USB) protocols.

[0235] The processor 1206 generates a recipe signal 1224. The recipe signal 1224 includes one or more parameter levels of the parameters of the RF signal 1222 output from the MPS 1202. The recipe signal 1224 further includes the frequency of the RF signal 1222. For example, the recipe signal 1224 includes the operating frequency of the MPS 1202. The recipe signal 1224 also includes one or more transition times. For example, if the recipe signal 1224 indicates that two parameter levels of the RF signal 1222 are achieved during each cycle of the clock signal 1102 (Figure 11A), the recipe signal 1224 further includes the transition time from the first parameter level to the second parameter level, and the transition time from the second parameter level to the first parameter level. The recipe signal 1224 is transmitted from the processor 1206 to the input unit 1210 via the transfer cable 1226.

[0236] In response to receiving the recipe signal 1224, the input unit 1210 generates a plurality of square wave signals and provides these square wave signals to the output unit 1212. Each square wave signal has a frequency received in the recipe signal 1224. The output unit 1212 generates an amplified square waveform based on the plurality of square wave signals received from the input unit 1210. Furthermore, the output unit 1212 shapes the envelope of the amplified square waveform, such as the peak-to-peak magnitude or zero-to-peak magnitude. For example, a shaping control signal 1220 is supplied from the input unit 1210 to the output unit 1212 to generate the envelope. As an example, the input unit 1210 generates the shaping control signal 1220 based on one or more parameter levels and one or more transition times received in the recipe signal 1224. The shaping control signal 1220 has a plurality of voltage values ​​for shaping the amplified square waveform. For example, the amplified rectangular waveform is shaped so that the first voltage value has a first parameter level, and the amplified rectangular waveform is shaped so that the second voltage value has a second parameter level.

[0237] The shaped amplified rectangular waveform is transmitted from the output unit 1212 to the reactance circuit 1214. The reactance circuit 1214 removes higher harmonics from the amplified rectangular waveform by filtering, etc., to generate an RF signal 1222, which is a shaped sinusoidal waveform with a fundamental frequency. The fundamental frequency is the frequency received from the recipe signal 1224. RF signal 1222 is an example of RF signal 116A or 116B. For example, if MPS 1202 is an example of LFMPS 102, then RF signal 1222 is an example of RF signal 116A. In this example, if MPS 1202 is an example of LFMPS 104, then RF signal 1222 is an example of RF signal 116B. The shaped sinusoidal waveform has an envelope with shapes such as digital pulse shape, continuous wave shape, arbitrary pulse shape, and multilevel pulse shape. The multilevel pulse shape has multiple parameter levels of RF signal 1222.

[0238] The RF signal 1222 is transmitted from the reactance circuit 1214 to the filter 1218 via the connector 1216. An example of the MPS 1202 is described in U.S. Patent No. 10,264,663, which is incorporated herein by reference in its entirety.

[0239] In some embodiments, the input section 1210 includes a controller board having a signal generator and further includes a gate driver, and the output section includes a half-bridge transistor circuit. The controller board includes a controller coupled to the signal generator, which controls the signal generator to generate a square wave signal at a predetermined frequency (e.g., high frequency or low frequency).

[0240] Figure 12A-2 is a diagram of one embodiment of system 1250 to illustrate further details of the input section 1210 and the output section 1212. The input section 1210 includes a controller 1252, a signal generator 1254, and a gate driver system 1256. The output section includes an FET circuit 1258, a direct current (DC) voltage source 1262, and a field-effect transistor (FET) circuit 1258. An example of a controller used herein is a combination of a processor and a memory device, where the processor is coupled to the memory device.

[0241] An example of a signal generator 1254 is a square wave oscillator, which generates a square wave signal (e.g., a square wave signal that is a digital waveform or a pulse train). The square wave periodically outputs pulses and has square pulses. For example, the square wave transitions between a first logic level (e.g., high or 1) and a second logic level (e.g., low or zero) during each cycle of the clock signal 1102 (Figure 11A). 1254 This generates a square wave signal at high or low frequency. An example of the gate driver system 1256 is a combination of a first gate driver, a second gate driver, and a NOT gate. The second gate driver is coupled to the NOT gate. An example of the FET circuit 1258 is a half-bridge FET circuit. For example, the half-bridge FET circuit has a first transistor and a second transistor, and the first and second transistors are coupled to each other. For example, the drain of the first transistor is coupled to the DC voltage source 1262, the source of the first transistor is coupled to the drain of the second transistor, and the source of the second transistor is coupled to ground potential. Also, the first gate driver of the gate driver system 1256 is coupled to the gate of the first transistor, and the NOT gate of the gate driver system 1256 is coupled to the gate of the second transistor. The output of the FET circuit 1258 is between the source of the first transistor and the drain of the second transistor.

[0242] The processor 1206 is coupled to the controller 1252 via a transfer cable 1226. The controller 1252 is coupled to the signal generator 1254. The signal generator 1254 is coupled to the inputs of the first and second gate drivers of the gate driver system 1256. The output of the first gate driver and the output of the NOT gate are coupled to the FET circuit 1258. The FET circuit 1258 is coupled to the DC voltage source 1262 and the reactance circuit 1214.

[0243] The controller 1252 receives the recipe signal 1224 from the processor 1206 via the transfer cable 1226. Upon receiving the recipe signal 1224, the controller 1252 identifies the frequency of the RF signal 1222 generated by the MPS 1202 and identifies one or more parameter levels and one or more transition times between parameter levels from the recipe signal 1224. The processor 1206 generates a trigger signal (e.g., an on command signal) and provides the trigger signal to the controller 1252 via the transfer cable 1226. For example, the processor 1206 transmits the trigger signal to the controller 1252 after a predetermined time. For example, the processor 1206 transmits the trigger signal to the controller 1252 of the LFMPS 102 (Figure 1) after a predetermined time has passed since the trigger signal was transmitted to the controller 1252 of the HFMPS 104 (Figure 1). The LFMPS 102 and HFMPS 104 are turned off until the trigger signal is received.

[0244] Upon receiving a trigger signal, the controller 1252 provides the frequency to the signal generator 1254. Also upon receiving the trigger signal, the controller 1252 generates a shaping control signal 1220 based on one or more parameter levels and one or more transition times. The controller 1252 provides the shaping control signal 1220 to the DC voltage source 1262.

[0245] Upon receiving a frequency, the signal generator 1254 generates a square wave signal 1264 and provides the square wave signal 1264 to the gate driver of the gate driver system 1256. The first gate driver of the gate driver system 1256 amplifies the parameters of the square wave signal 1264 and outputs the first amplified square wave signal 1266. The second gate driver of the gate driver system 1256 amplifies the parameters of the square wave signal 1264 and outputs the second amplified square wave signal, which is provided to the NOT gate. The NOT gate inverts the second amplified square wave signal and outputs the inverted signal 1268, which is also a square wave signal.

[0246] Signals 1266 and 1268 are supplied to the gate of FET circuit 1258. The first transistor of FET circuit 1258 is turned on and off according to the first amplified square wave signal 1266, and the second transistor of FET circuit 1258 is turned on and off according to the inverting signal 1268, so that the amplified square wave signal 1272 is output at the output of FET circuit 1258.

[0247] Upon receiving the shaping control signal 1220, the DC voltage source 1262 provides a voltage signal 1270 to the FET circuit 1258. The voltage signal 1270 has voltage levels that are pulsed out according to one or more transition times indicated by the shaping control signal 1220. Furthermore, the voltage signal 1270 has one or more voltage levels that are generated based on one or more parameter levels indicated by the shaping control signal 1220. The parameters of the amplified square wave signal 1272 are pulsed out at one or more transition times indicated by the voltage signal 1270 and have one or more parameter levels similarly indicated by the voltage signal 1270. The reactance circuit receives the amplified square wave signal 1272, removes harmonics from the amplified square wave signal 1272, and outputs an RF signal 1222 having a fundamental frequency (e.g., high frequency or low frequency).

[0248] If the RF signal 1222 is a continuous wave signal, the recipe signal 1224 includes a single parameter level and does not include transition time. Upon receiving the recipe signal 1224, the controller 1252 generates a shaping control signal 1220, indicating a single parameter level and no transition time. In response to receiving the shaping control signal 1220, the DC voltage source 1262 generates a voltage signal 1270 having a single voltage level. Upon receiving the single voltage level and signals 1266 and 1268, the FET circuit 1258 generates an amplified rectangular waveform with a single parameter level based on the single voltage level. 1272 Outputs.

[0249] When the processor 1206 transmits an off command signal to the controller 1252 via the transfer cable 1226, the controller 1252 transmits an off control signal to the signal generator 1254. For example, the processor 1206 transmits an off command signal to the controller 1252 after a predetermined time. Upon receiving the off control signal, the signal generator 1254 stops generating the square wave signal 1264, and the MPS 1202 does not generate the RF signal 1222.

[0250] Figure 12B shows the RF generator. 1282 This figure illustrates one embodiment of system 1280 to illustrate the details. System 1280 includes a host computer 1204 and an RF generator 1282. RF generator 1282 is an example of one of the following: LF source RFG402, HF source RFG404, LF bias RFG302, and HF bias RF304 (Figures 3A and 4).

[0251] The RF generator 1282 includes a digital signal processor (DSP) 1284, parameter controllers PRS1 and PRS2, frequency controller FC, driver DRVR, and power supply PS. An example of a driver used herein is one or more transistors. An example of the power supply PS is an oscillator that generates a sinusoidal RF signal.

[0252] The processor 1206 is coupled to the DSP 1284 via a transfer cable 1290. The DSP 1284 is coupled to the parameter controllers PRS1 and PRS2 and the frequency controller FC. The frequency controller FC and parameter controllers PRS1 and PRS2 are coupled to the driver DRVR, and the driver DRVR is coupled to the power supply PS. The DSP 1284 is coupled to the driver DRVR.

[0253] The processor 1206 generates a recipe signal 1286 and provides the recipe signal 1286 to the DSP 1284 via a transfer cable 1290. As an example, the recipe signal 1286 includes a first parameter level of the RF signal 1288 generated by the RF generator 1282, a second parameter level of the RF signal 1288, and the frequency of the RF signal 1288. The RF signal 1288 is one of the examples of RF signals 330, 332, 420, and 422 (Figures 3A and 4). In this example, the first parameter level represents state S1 of the RF signal 1288, the second parameter level represents state S2 of the RF signal 1288, and the recipe signal 1286 includes a first transition time for the transition from the second parameter level to the first parameter level and a second transition time for the transition from the first parameter level to the second parameter level during each clock cycle of the clock signal 1102 (Figure 11A).

[0254] The DSP1284 receives a recipe signal 1286 from the processor 1206 and identifies the first and second parameter levels from the recipe signal 1286. The DSP1284 also identifies the first and second transition times from the recipe signal 1286. The DSP1284 provides the first parameter level and first transition time to parameter controller PRS1 and the second parameter level and second transition time to parameter controller PRS2. Parameter controller PRS1 stores the first parameter level and first transition time in its memory device, and parameter controller PRS2 stores the second parameter level and second transition time in its memory device. The DSP1284 also provides the frequency to frequency controller FC. Frequency controller FC stores the frequency in its memory device.

[0255] The processor 1206 generates a trigger signal and transmits it to the DSP 1284 via the transfer cable 1290. For example, the processor 1206 transmits the trigger signal to the DSP 1284 after a predetermined time. For example, the processor 1206 transmits the trigger signal to the DSP 1284 of the LF source RFG402 after a predetermined time has passed since the trigger signal was transmitted to the DSP 1284 of the HF source RFG404.

[0256] When receiving a trigger signal (e.g., a digital pulse, etc.) from the processor 1206, the DSP 1284 transmits the trigger signal to the parameter controllers PRS1 and PRS2 and the frequency controller FC. When receiving the trigger signal, the parameter controller PRS1 generates a control signal at the first transition time based on the first parameter level of state S1, and transmits the control signal to the driver DRVR. Also, when receiving the trigger signal, the frequency controller FC generates a control signal and transmits the control signal to the driver DRVR. In response to receiving the control signals from the parameter controller PRS1 and the frequency controller FC, the driver generates a drive signal of state S1 and transmits the drive signal to the power supply PS. The power supply PS generates the first parameter level of the RF signal 1288 at the first transition time in response to receiving the drive signal of state S1.

[0257] Furthermore, when receiving the trigger signal, the parameter controller PRS2 generates a control signal at the second transition time based on the second parameter level of state S2, and transmits the control signal to the driver DRVR. In response to receiving the control signals from the parameter controller PRS2 and the frequency controller FC, the driver generates a drive signal of state S2 and transmits the drive signal to the power supply PS. The power supply PS generates the second parameter level of the RF signal 1288 at the second transition time in response to receiving the drive signal of state S2. In this way, the parameters of the RF signal 1288 transition from the second parameter level to the first parameter level at the first transition time, and transition from the first parameter level to the second parameter level at the second transition time.

[0258] When the processor 1206 transmits an off command signal to the DSP 1284 via the transfer cable 1290, the DSP 1284 transmits an off control signal to the driver DRVR. For example, the processor 1206 transmits an off command signal to the DSP 1284 after a predetermined time. When receiving the off control signal, the driver DRVR stops transmitting the drive signal to the power supply PS. When the drive signal is not received, the power supply PS turns off and stops generating the RF signal 1288.

[0259] In one embodiment, when the RF signal generated by the RF generator 1282 includes a single parameter level (such as the first parameter level), another RF generator is used. Except that the other RF generator does not include the parameter controller PRS2, the other RF generator has the same structure as the RF generator 1282. The processor 1206 generates another recipe signal and provides the other recipe signal to the DSP 1284. As an example, except that the other recipe signal does not include the first and second transition times and does not include the second parameter level of state S2, the other recipe signal is similar to the recipe signal 1286. The DSP 1284 receives the other recipe signal from the processor 1206 and identifies the first parameter level from the recipe signal 1286. The DSP 1284 provides the first parameter level to the parameter controller PRS1. The parameter controller PRS1 stores the first parameter level in the memory device of the parameter controller PRS1. When receiving a trigger signal from the processor 1206, the DSP 1284 transmits the trigger signal to the parameter controller PRS1 and the frequency controller FC. When receiving the trigger signal, the parameter controller PRS1 generates a control signal based on the first parameter level of state S1 and transmits the control signal to the driver DRVR. Also, when receiving the trigger signal, the frequency controller FC generates a control signal and transmits the control signal to the driver DRVR. In response to receiving the control signals from the parameter controller PRS1 and the frequency controller FC, the driver generates a drive signal for state S1 and transmits the drive signal to the power supply PS. The power supply PS generates the first parameter level of the RF signal 1288 in response to receiving the drive signal for state S1.

[0260] Figure 13 is a diagram of one embodiment of system 1300 illustrating the control of a variable capacitor 1306. System 1300 includes a host computer 1204, a driver 1302, a motor 1304, and a variable capacitor 1306. The variable capacitor 1306 comprises a first capacitor 110, a second capacitor 112, a third capacitor 908 (Figure 9A), a fourth capacitor 910 (Figure 9A). 9A Examples include the third capacitor 954 (Figure 9B), and the fourth capacitor 956 (Figure 9B).

[0261] An example of motor 1304 is an AC motor including a stator and rotor. An example of driver 1302 is one or more transistors. Processor 1206 is coupled to driver 1302, driver 1302 is coupled to motor 1304, and motor 1304 is coupled to capacitor 1306. Processor 1206 generates and transmits a control signal based on the capacitance achieved by capacitor 1306. Upon receiving the control signal, driver 1302 generates a drive signal (e.g., a current signal) and transmits the drive signal to motor 1304. Motor 1304 changes the capacitance of capacitor 1306 by changing the amount of overlap between the first and second plates of capacitor 1306.

[0262] Figure 14 is a diagram of one embodiment of a plasma chamber 1400 illustrating a solenoid coil 1402. The plasma chamber 1400 includes the solenoid coil 1402 and a substrate support 310. The solenoid coil 1402 is located above the dielectric window 314 and is wound around a dielectric mandrel 1403. The solenoid coil 1402 has an end 1404 and the opposite end 1406. As an example, when the solenoid coil 1402 is used instead of the RF coil 114, the end 1404 is coupled to point 122 (Figures 1, 7A, 7B, and 9A). As another example, when the solenoid coil 1402 is used instead of the RF coil 114, the end 1404 is coupled to output 416 (Figure 4). As yet another example, when the solenoid coil 1402 is used instead of the RF coil 904, the end 1404 is coupled to a fourth capacitor 910 (Figure 9A). As yet another example, when a solenoid coil 1402 is used instead of the RF coil 904, terminal 1404 is coupled to point 960 (Figure 9B). As yet another example, when a solenoid coil 1402 is used instead of the RF coil 904, terminal 1404 is coupled to filter 983 (Figure 9C). As yet another example, when a solenoid coil 1402 is used instead of the RF coil 904, terminal 1404 is coupled to filter 992 (Figure 9D).

[0263] When the RF signal 1408 is received by the solenoid coil 1402, a magnetic field is generated by the solenoid coil 1402 and spreads through the dielectric window 314 into the plasma chamber 1400. RF signals 1408 are RF signals 123 (Figure 1), 426 (Figure 4), 706 (Figure 7A), 756 (Figure 7B), 922 (Figure 9A), 920 (Figure 9A), 966 (Figure 9B), 970 (Figure 9D), 984 (Figure 9A). 9C ), and 994 (Figure 9D) is an example of any of the following. When one or more process gases are supplied to the plasma chamber 1400 in addition to the RF signal 1408, the plasma is struck or maintained within the plasma chamber 1400 to process the substrate S. As the plasma is formed within the plasma chamber 1400, the RF power is reflected from the plasma chamber 1400 to point 1404 via the solenoid coil 1402 in the form of a reflected RF signal 1410. The reflected RF signal 1410 is an example of any of the reflected RF signals 115 (Figure 1), 428 (Figure 4), 708 (Figure 7A), 758 (Figure 7B), 924 (Figure 9A), 930 (Figure 9A), 980 (Figure 9B), 974 (Figure 9B), 986 (Figure 9C), and 996 (Figure 9D).

[0264] In one embodiment, referring to Figure 9A, a solenoid coil 1402 is used instead of the RF coil 114, and a different solenoid coil is used instead of the RF coil 904.

[0265] In one embodiment, referring to Figure 9B, a solenoid coil 1402 is used instead of the RF coil 114, and another solenoid coil is used instead of the RF coil 904.

[0266] Figure 15 shows LFMPS102 and HFMPS 104 This figure illustrates one embodiment of a plasma system 1500 having a substrate support 310 to illustrate its use. The plasma system 1500 includes an LF source RFG402, an HF source RFG404, a dual-frequency matching unit 406, a plasma chamber 308, an LFMPS102, an HFMPS104, a first filter 106, a second filter 108, a first capacitor 110, and a second capacitor 112. In the plasma system 1500, point 122 is coupled to the lower electrode 311 via an RF connection 125 (e.g., an RF transmission line).

[0267] A modified RF signal 426 is supplied to the RF coil 312, a combined RF signal is supplied to the lower electrode 311, and one or more process gases are supplied to the plasma chamber 308, thereby generating or maintaining plasma within the plasma chamber 308. As the plasma is generated or maintained, RF power is reflected from the plasma through the lower electrode 311 toward the RF connection 125 in the form of a reflected RF signal 115.

[0268] Figure 16A is a diagram of one embodiment of system 1600 illustrating a master-slave configuration. In this master-slave configuration, LFMPS102 is the control side and HFMPS104 is the controlled side. For example, the controller of LFMPS102 is coupled to the controller of HFMPS104 via a transfer cable 1602. Rather than the host computer 1204 (Figure 12) providing the high frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116B generated by HFMPS104 in the recipe signal 1224 (Figure 12A-1), the controller of LFMPS102 generates the recipe signal 1604 and transmits the recipe signal 1604 to the controller of HFMPS104 via the transfer cable 1602. Recipe signal 1604 is an example of recipe signal 1224 (Figure 12A-2). The recipe signal 1604 includes the high frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116B output by the HFMPS 104. The HFMPS 104 generates the RF signal 116B based on the high frequency, one or more parameter levels, and transition times between parameter levels indicated in the recipe signal 1604.

[0269] Figure 16B is a diagram illustrating one embodiment of system 1610 to illustrate a master-slave configuration. In this master-slave configuration, HFMPS 104 is the control side and LFMPS 102 is the controlled side. For example, the controller of HFMPS 104 is coupled to the controller of LFMPS 102 via a transfer cable 1612. The host computer 1204 (Figure 12) sends a recipe signal 1224 (Figure 12A-1) to LFMPS 102Instead of providing the low frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116A generated by the system, the HFMPS104 controller generates a recipe signal 1614 and transmits the recipe signal 1614 to the LFMPS102 controller via the transfer cable 1612. Recipe signal 1614 is an example of recipe signal 1224 (Figure 12A-2). Recipe signal 1614 includes the low frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116A output by the LFMPS102. The LFMPS102 generates the RF signal 116A based on the low frequency, one or more parameter levels, and transition times between parameter levels indicated in the recipe signal 1614.

[0270] Figure 16C shows one embodiment of system 1620 illustrating a master-slave configuration. In this master-slave configuration, the LF source RFG402 is the control side and the HFMPS104 is the controlled side. For example, the DSP of the LF source RFG402 is coupled to the controller of the HFMPS104 via a transfer cable 1622. Rather than the host computer 1204 (Figure 12) providing the high frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116B generated by the HFMPS104 in the recipe signal 1224 (Figure 12A-1), the DSP of the LF source RFG402 generates the recipe signal 1624 and transmits the recipe signal 1624 to the controller of the HFMPS104 via the transfer cable 1622. Recipe signal 1624 is an example of recipe signal 1224 (Figure 12B). The recipe signal 1624 includes the high frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116B output by the HFMPS 104. The HFMPS 104 generates the RF signal 116B based on the high frequency, one or more parameter levels, and transition times between parameter levels indicated in the recipe signal 1624.

[0271] Figure 16D is a diagram of one embodiment of system 1630 illustrating a master-slave configuration. In this master-slave configuration, the HF source RFG404 is the control side and the LFMPS102 is the controlled side. For example, the DSP of the HF source RFG404 is coupled to the controller of the LFMPS102 via a transfer cable 1632. Rather than the host computer 1204 (Figure 12) providing the low frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116A generated by the LFMPS102 in the recipe signal 1224 (Figure 12A-1), the DSP of the HF source RFG404 generates the recipe signal 1634 and transmits the recipe signal 1634 to the controller of the LFMPS102 via the transfer cable 1632. Recipe signal 1634 is an example of recipe signal 1224 (Figure 12A-2). The recipe signal 1634 includes the low frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 116A output by the LFMPS 102. The LFMPS 102 generates the RF signal 116A based on the low frequency, one or more parameter levels, and transition times between parameter levels indicated in the recipe signal 1634.

[0272] Figure 16E is a diagram of one embodiment of system 1640 to illustrate a master-slave configuration. In this master-slave configuration, LFMPS102 is the control side and HF source RFG404 is the controlled side. For example, the controller of LFMPS102 is coupled to the DSP of HF source RFG404 via a transfer cable 1642. Rather than the host computer 1204 (Figure 12) providing the high frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 422 generated by HF source RFG404 in the recipe signal 1286 (Figure 12B), the controller of LFMPS102 generates the recipe signal 1644 and transmits the recipe signal 1644 to the DSP of HF source RFG404 via the transfer cable 1642. Recipe signal 1644 is an example of recipe signal 1286 (Figure 12B). The recipe signal 1644 includes the high frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 422 output by the HF source RFG404. The HF source RFG404 generates the RF signal 422 based on the high frequency, one or more parameter levels, and transition times between parameter levels indicated in the recipe signal 1644.

[0273] Figure 16F shows one embodiment of system 1650 to illustrate a master-slave configuration. In this master-slave configuration, HFMP104 is the control side and LF source RFG402 is the controlled side. For example, the controller of HFMPS104 is coupled to the DSP of LF source RFG402 via a transfer cable 1652. Rather than the host computer 1204 (Figure 12) providing the low frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 420 generated by LF source RFG402 in a recipe signal 1286 (Figure 12B), the controller of HFMPS104 generates the recipe signal 1654 and transmits the recipe signal 1654 to the DSP of LF source RFG402 via the transfer cable 1652. Recipe signal 1654 is an example of recipe signal 1286 (Figure 12B). The recipe signal 1654 includes the low frequency, one or more parameter levels, and transition times between parameter levels of the RF signal 420 output by the LF source RFG402. The LF source RFG402 generates the RF signal 420 based on the low frequency, one or more parameter levels, and transition times between parameter levels indicated in the recipe signal 1654.

[0274] The embodiments described herein may be implemented in a variety of computer system configurations, including handheld hardware units, microprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, and the like. The embodiments can also be implemented in a distributed computing environment in which tasks are performed by remote processing hardware units linked over a network.

[0275] In some embodiments, the controller is part of a system which may be part of the examples described above. Such a system includes semiconductor processing equipment such as one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems are integrated with electronics for the fabrication of integrated circuits to control the operation of the system before, during, and after processing semiconductor wafers or substrates. This electronics is referred to as a “controller” capable of controlling various components or sub-components of one or more systems. Depending on the processing requirements and / or the type of system, the controller is programmed to control any of the processes disclosed herein, such as the delivery of processing gases, temperature setting (e.g., heating and / or cooling), pressure setting, vacuum setting, power setting, RF generator setting, RF matching circuit setting, frequency setting, flow rate setting, fluid delivery setting, position and operation setting, loading and unloading of wafers to and from tools and other transport tools and / or load locks that connect to or interface with the system.

[0276] Broadly speaking, in various embodiments, a controller is defined as an electronic device having various integrated circuits, logic, memory, and / or software that, for example, receive and issue commands, control operations, enable cleaning operations, enable endpoint measurement, etc. Integrated circuits include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as ASICs, PLDs, and / or 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 parameters, factors, variables, etc., for performing a specific process on or for a semiconductor wafer or for a system. In some embodiments, program instructions are part of a recipe determined by a process engineer to achieve one or more processing steps during the manufacture of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or wafer molds.

[0277] In some embodiments, the controller is part of a computer that is integrated into the system, coupled to the system, or otherwise networked to the system, or a combination thereof. For example, the controller is all or part of a host computer system in a manufacturing plant that is in the “cloud” or enables remote access to wafer processing. By enabling remote access to the system, the computer can monitor the current progress of an assembly operation, review the history of past assembly operations, verify trends or performance criteria from multiple assembly operations, modify parameters of the current process, set processing steps following the current process, or start a new process.

[0278] In some embodiments, a remote computer (e.g., a server) provides process recipes to the system through a network including a local network or the Internet. The remote computer includes a user interface that enables input or programming of parameters and / or settings, and the parameters and / or settings are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data that define the parameters, factors, and / or variables for each processing step performed during one or more operations. It should be understood that such parameters, factors, and / or variables are specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by including one or more separate controllers that are networked together and operate towards a common purpose such as the processes and controls described herein. Examples of controllers distributed for such purposes include one or more integrated circuits on a chamber that are combined to control processes on the chamber and communicate with one or more integrated circuits remotely located (e.g., at the platform level or as part of a remote computer).

[0279] By way of example, and not limitation, in various embodiments, exemplary systems to which the method is applicable include plasma etching chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, clean chambers or modules, bevel edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing system associated with or used in the assembly and / or manufacture of semiconductor wafers.

[0280] It should be further noted that in some embodiments, the above operations are applicable to various types of plasma chambers (e.g., plasma chambers containing inductively coupled plasma (ICP) reactors, transformer-coupled plasma chambers, capacitively coupled plasma chambers, conductive tools, dielectric tools, plasma chambers containing electron cyclotron resonance (ECR) reactors, etc.). For example, one or more RF generators are coupled to inductors within an ICP reactor. Examples of inductor shapes include solenoids, dome-shaped coils, flat coils, etc.

[0281] As described above, depending on the process steps performed by the tool, or each step, the host computer communicates with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, the main computer, other controllers, or tools used for material transport to move wafer containers to tool locations and / or into and out of load ports within the semiconductor manufacturing plant.

[0282] In consideration of the embodiments described above, it should be understood that some embodiments employ various operations of computer implementations, including data stored in a computer system. These operations involve physically manipulating physical quantities. Any operations that form part of the embodiments described herein are useful mechanical operations.

[0283] Some embodiments also relate to hardware units or devices for performing these operations. The devices are specifically configured for special-purpose computers. If defined as a special-purpose computer, this computer performs other processing, program execution, or routines that are not part of the special purpose, while remaining operational for that special purpose.

[0284] In some embodiments, the operations may be stored in computer memory or cache, or processed by a computer selectively launched or configured by one or more computer programs retrieved via a computer network. When data is retrieved via a computer network, this data may be processed by other computers on the computer network, for example, a cloud of computing resources.

[0285] Furthermore, in one or more embodiments, the code can be produced as computer-readable code on a non-primary computer-readable medium. The non-primary computer-readable medium is a data storage hardware unit (e.g., a memory device) that stores data, which is then read by a computer system. Examples of non-primary computer-readable mediums include hard drives, network-attached storage (NAS), ROM, RAM, compact disc-ROM (CD-ROM), writable CD (CD-R), rewritable CD (CD-RW), magnetic tape, and other optical and non-optical data storage hardware units. In some embodiments, the non-primary computer-readable medium includes computer-readable tangible media distributed via a network-connected computer system so that the computer-readable code is stored and executed in a distributed manner.

[0286] Although the above method operations were described in a specific order, it should be understood that in various embodiments, other housekeeping operations may be performed between the operations, the method operations may be timed to occur at slightly different times, they may be distributed in a system that allows the method operations to occur at various intervals, or they may be performed in a different order than described above.

[0287] It should be further noted that in certain embodiments, one or more features from any of the embodiments described above may be combined with one or more features from any of the other embodiments described above, without departing from the scope of the various embodiments described herein.

[0288] While the embodiments described above have been explained in some detail for clarity, it will be apparent that certain changes and modifications can be made within the scope of the appended claims. Therefore, these embodiments are considered illustrative and not restrictive, and are not limited to the details shown herein.

Claims

1. It is a system, A first matchless plasma source configured to generate a first sinusoidal waveform generated based on a first rectangular waveform, wherein the first sinusoidal waveform has a first frequency, A first filter coupled to the first matchless plasma source and configured to filter a second frequency so as not to interfere with the first sinusoidal waveform, A first capacitive circuit is coupled to the first filter and configured to output a first radio frequency (RF) signal by balancing the reactance of the first filter and the reactance of the RF coil of the plasma chamber, and is configured to provide the first RF signal to a point coupled to the RF coil. A second matchless plasma source configured to generate a second sinusoidal waveform generated based on a second rectangular waveform, wherein the second sinusoidal waveform has the second frequency, A second filter coupled to the second matchless plasma source and configured to filter the first frequency so as not to interfere with the second sinusoidal waveform, A second capacitive circuit is coupled to the second filter and configured to output a second RF signal by balancing the reactance of the second filter with the reactance of the RF coil, and is configured to provide the second RF signal to the point, A system equipped with these features.

2. The system according to claim 1, A system in which the first RF signal is combined with the second RF signal at the point, and the combined RF signal is provided to the RF coil.

3. The system according to claim 1, A system in which the second frequency is greater than the first frequency.

4. The system according to claim 1, A system further comprising the plasma chamber including the RF coil and the substrate support.

5. The system according to claim 4, A first bias RF generator configured to generate a third RF signal, A matching circuit coupled to the first bias RF generator, A second bias RF generator coupled to the matching circuit and configured to generate a fourth RF signal, wherein the matching circuit is configured to receive the third RF signal and the fourth RF signal, correct the impedance of the third RF signal and the fourth RF signal to output a corrected RF signal, and provide the corrected RF signal to the substrate support; A system that further enhances this feature.

6. The system according to claim 4, The aforementioned substrate support is coupled to ground potential in the system.

7. The system according to claim 1, The first capacitive circuit is configured to receive a reflected RF signal having RF power reflected from the plasma chamber, the reflected RF signal having the second frequency, in the system.

8. The system according to claim 1, The second capacitive circuit is configured to receive a reflected RF signal having RF power reflected from the plasma chamber, wherein the reflected RF signal has the first frequency.

9. The system according to claim 1, A system in which there is no matching device between the first matchless plasma source and the RF coil, and there is no matching device between the second matchless plasma source and the RF coil.

10. It is a system, A matchless plasma source configured to generate a sinusoidal waveform based on a rectangular waveform, wherein the sinusoidal waveform has a first frequency, A first filter coupled to the matchless plasma source and configured to filter a second frequency so as not to interfere within the sinusoidal waveform, A capacitive circuit is coupled to the first filter and configured to output a first radio frequency (RF) signal by balancing the reactance of the first filter and the reactance of the RF coil of the plasma chamber, and is configured to provide the first RF signal to a point coupled to the RF coil. A source RF generator configured to generate a second RF signal having the second frequency, An impedance matching network coupled to the source RF generator and configured to receive the second RF signal, correct the impedance of the second RF signal, and output a corrected RF signal, comprising a second filter configured to filter the first frequency so as not to interfere with the second RF signal, and configured to provide the corrected RF signal to the point, A system equipped with these features.

11. The system according to claim 10, The system is configured such that the point combines the first RF signal with the modified RF signal and provides the combined RF signal to the RF coil.

12. The system according to claim 10, A system in which the second frequency is greater than the first frequency, equal to the first frequency, or less than the first frequency.

13. The system according to claim 10, A system further comprising the plasma chamber including the RF coil and the substrate support.

14. The system according to claim 13, A first bias RF generator configured to generate a third RF signal, A matching circuit coupled to the first bias RF generator, A second bias RF generator coupled to the matching circuit and configured to generate a fourth RF signal, wherein the matching circuit is configured to receive the third RF signal and the fourth RF signal, correct the impedance of the third RF signal and the fourth RF signal to output a corrected RF signal, and provide the corrected RF signal to the substrate support. A system that further enhances this feature.

15. The system according to claim 13, The aforementioned substrate support is coupled to ground potential in the system.

16. The system according to claim 10, The capacitive circuit is configured to receive a reflected RF signal having RF power reflected from the plasma chamber, and the reflected RF signal has the second frequency, in the system.

17. The system according to claim 10, A system in which there is no matching device, including a physical housing, between the matchless plasma source and the RF coil.

18. It is a system, A first matchless plasma source configured to generate a first sinusoidal waveform generated based on a first rectangular waveform, wherein the first sinusoidal waveform has a first frequency, A first filter coupled to the first matchless plasma source and configured to filter a second frequency so as not to interfere with the first sinusoidal waveform, A first capacitive circuit is coupled to the first filter and configured to output a first RF signal by balancing the reactance of the first filter with the reactance of the first radio frequency (RF) coil of the plasma chamber, and is configured to provide the first RF signal to a point coupled to the first RF coil. A second matchless plasma source configured to generate a second sinusoidal waveform generated based on a second rectangular waveform, wherein the second sinusoidal waveform has the second frequency, A second filter coupled to the second matchless plasma source and configured to filter the first frequency so as not to interfere with the second sinusoidal waveform, A second capacitive circuit coupled to the second filter and configured to output a second RF signal by balancing the reactance of the second filter, the reactance of the first RF coil, and the reactance of the second RF coil of the plasma chamber, The system comprises a signal splitter coupled to the second capacitive circuit and configured to split the second RF signal into a third RF signal and a fourth RF signal, and including the third capacitive circuit and the fourth capacitive circuit, The system is configured such that the third capacitive circuit receives the third RF signal and balances the reactance of the first RF coil of the plasma chamber with the reactance of the second filter to provide a fifth RF signal to the point, and the fourth capacitive circuit receives the fourth RF signal and balances the reactance of the second RF coil with the reactance of the second filter to provide a sixth RF signal to the second RF coil.

19. The system according to claim 18, The system is configured such that the point combines the first RF signal with the fifth RF signal to provide a seventh RF signal to the first RF coil.

20. The system according to claim 18, A system in which the second frequency is greater than the first frequency.

21. The system according to claim 18, A system further comprising the plasma chamber including the first RF coil, the second RF coil, and a substrate support.

22. The system according to claim 21, A first bias RF generator configured to generate a seventh RF signal, A matching circuit coupled to the first bias RF generator, A second bias RF generator coupled to the matching circuit and configured to generate an eighth RF signal, wherein the matching circuit is configured to receive the seventh RF signal and the eighth RF signal, correct the impedance of the seventh RF signal and the eighth RF signal to output a corrected RF signal, and provide the corrected RF signal to the substrate support; A system that further enhances this feature.

23. The system according to claim 21, The aforementioned substrate support is coupled to ground potential in the system.

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