Substrate processing tool using fast matching network impedance switching for rapid alternating processes

Abstract

The transformer-coupled capacitively tuned (TCCT) matching network includes a coarse tuning circuit and a fine tuning circuit. The coarse tuning circuit receives a first RF signal and includes a first tuning variable capacitance circuit and a first load variable capacitance circuit. The first tuning variable capacitance circuit adjusts a frequency of the first RF signal to generate a second RF signal. The first load variable capacitance circuit is connected to a ground reference terminal and configured to adjust an impedance of the TCCT matching network. The fine tuning circuit includes a second tuning variable capacitance circuit and a second load variable capacitance circuit. The second tuning variable capacitance circuit fine tunes a frequency of the second RF signal. The second load variable capacitance circuit is connected to the ground reference terminal and fine tunes an impedance of the transformer-coupled capacitively tuned matching network.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 295,255, filed December 30, 2021. The entire disclosure of the above application is incorporated herein by reference.

[0002] The present disclosure relates to rapid alternating etch and deposition processes and systems. [Background technology]

[0003] The background discussion provided herein is intended to generally present the context of the present disclosure. The work of the presently named inventors, to the extent that their work is described in this background section, is not admitted explicitly or implicitly as prior art to the present disclosure, as are aspects of the description that may not otherwise be considered prior art at the time of filing.

[0004] During the manufacture of semiconductor devices, etch and deposition processes may be carried out in a processing chamber. An ionized gas, or plasma, may be introduced into the plasma chamber to etch (or remove) material from a substrate, such as a semiconductor wafer, and to sputter or deposit material onto the substrate. Creating a plasma for use in a manufacturing or fabrication process generally begins by introducing a process gas into the processing chamber. The substrate is disposed in the processing chamber on a substrate support, such as an electrostatic chuck or pedestal.

[0005] The processing chamber may include a transformer coupled plasma (TCP) reactor coil. A radio frequency (RF) signal generated by a power supply is fed to the TCP reactor coil. A dielectric window, a material such as a structured or ceramic, is incorporated into the upper surface of the processing chamber. The dielectric window allows the RF signal to be transmitted from the TCP reactor coil to the interior of the processing chamber. The RF signal excites gas molecules in the processing chamber to generate a plasma.

[0006] The TCP reactor coil is driven by a transformer coupled capacitive tuning (TCCT) matching network. The TCCT matching network receives an RF signal provided by a power supply and allows tuning of the power provided to the TCP reactor coil. The TCCT matching network may include variable capacitors. Each of the variable capacitors includes a stationary electrode and a movable electrode. The position of the movable electrode relative to the stationary electrode is directly related to the capacitance of the corresponding capacitor. The movable electrode may be moved to different positions relative to the stationary electrode via a motor.

[0007] The power provided to each of the TCP reactor coils is based on the position of the movable electrode of the variable capacitor relative to the respective stationary electrode. The ratio of power between the TCP coils is also based on the position of the movable electrode. The power ratio or ratios provided during the etch process may be different from the power ratio or ratios provided during the deposition process. Summary of the Invention

[0008] According to some embodiments, the present disclosure discloses a transformer-coupled capacitive tuning network. The transformer-coupled capacitive tuning network includes a coarse adjustment circuit and a fine adjustment circuit. The coarse adjustment circuit is configured to receive a first radio frequency (RF) signal and includes a first tuning variable capacitance circuit and a first load variable capacitance circuit. The first tuning variable capacitance circuit is configured to adjust a frequency of the first RF signal to generate a second RF signal. The first load variable capacitance circuit is connected to a ground reference terminal and configured to adjust an impedance of the transformer-coupled capacitive tuning network. The fine adjustment circuit includes a second tuning variable capacitance circuit and a second load variable capacitance circuit. The second tuning variable capacitance circuit is configured to fine tune a frequency of the second RF signal. The capacitance range of the second tuned variable capacitance circuit is smaller than the capacitance range of the first tuned variable capacitance circuit. The second load variable capacitance circuit is connected to the ground reference terminal and configured to fine tune the impedance of the transformer coupled capacitive tuned matching network. The capacitance range of the second load variable capacitance circuit is smaller than the capacitance range of the first load variable capacitance circuit.

[0009] In some embodiments, the second tuneable variable capacitance circuit is connected in parallel with the first tuneable variable capacitance circuit. The second load variable capacitance circuit is connected in parallel with the first load variable capacitance circuit.

[0010] In some embodiments, the first tuned variable capacitance circuit includes a first variable capacitor. The second tuned variable capacitance circuit includes a second variable capacitor connected in parallel with the first variable capacitor. The first load variable capacitance circuit includes a third variable capacitor. The second load variable capacitance circuit includes a fourth variable capacitor connected in parallel with the third variable capacitor.

[0011] In some embodiments, the first tuned variable capacitance circuit includes a first variable capacitor. The second tuned variable capacitance circuit includes a first capacitor connected in parallel with the first variable capacitor. The first load variable capacitance circuit includes a second variable capacitor. The second load variable capacitance circuit includes a second capacitor connected in parallel with the second variable capacitor.

[0012] In some embodiments, the second tuned variable capacitance circuit includes a third variable capacitor connected in series with the first fixed capacitor, and the second load variable capacitance circuit includes a fourth variable capacitor connected in series with the second fixed capacitor.

[0013] In some embodiments, the transformer coupled capacitive tuned coupling network further includes a first motor configured to change a capacitance of the first tuned variable capacitance circuit, a second motor configured to change a capacitance of the first load variable capacitance circuit, a first relay configured to change a capacitance of the second tuned variable capacitance circuit, and a second relay configured to change a capacitance of the second load variable capacitance circuit.

[0014] According to some embodiments, the present disclosure discloses a system including a transformer-coupled capacitive tuned network and one or more controllers configured to perform a rapid alternating process that includes repetitively switching between an etch process and a deposition process, and to set a fine tuning circuit to be in a first state during the etch process and to be in a second state during the deposition process.

[0015] In some embodiments, the one or more controllers are configured to change a state of at least one of the second tuned variable capacitance circuit or the second load variable capacitance circuit during a transition between the etch process and the deposition process.

[0016] In some embodiments, the system further includes a sensor configured to measure a phase and a magnitude of the first RF signal, and the one or more controllers are configured to adjust at least one of the capacitance of the first tuned variable capacitance circuit or the capacitance of the first load variable capacitance circuit based on the phase and magnitude of the first RF signal.

[0017] In some embodiments, the second tuneable variable capacitance circuit includes a first relay configured to switch between a first capacitance and a second capacitance, and the second load variable capacitance circuit includes a second relay configured to switch between a third capacitance and a fourth capacitance.

[0018] According to some embodiments, the present disclosure discloses a system including a transformer coupled capacitive tuned coupling network and one or more controllers configured to perform a rapid alternating process including repeatedly switching between an etch process and a deposition process, and to set a state of a first relay and a state of a second relay to be in a first configuration during the etch process and to be in a second configuration during the deposition process.

[0019] In some embodiments, the one or more controllers are configured to transition the first relay between the first capacitance and the second capacitance when transitioning between the etch process and the deposition process, and to refrain from transitioning the second relay between the third capacitance and the fourth capacitance when transitioning between the etch process and the deposition process.

[0020] In some embodiments, the one or more controllers are configured to transition the first relay between a first capacitance and a second capacitance when transitioning between the etch process and the deposition process, and transition the second relay between a third capacitance and a fourth capacitance when transitioning between the etch process and the deposition process.

[0021] According to some embodiments, the present disclosure discloses a rapid alternating process method including: setting a capacitance of a first tuned variable capacitance circuit of a transformer-coupled capacitive tuning matching network, the first tuned variable capacitance circuit being configured to tune a frequency of a first RF signal to generate a second RF signal; setting a capacitance of a first load variable capacitance circuit connected to a ground reference terminal and configured to tune an impedance of the transformer-coupled capacitive tuning matching network; and setting a capacitance of a second tuned variable capacitance circuit and a second load variable capacitance circuit for an etch process. The second tuned variable capacitance circuit is configured to fine tune a frequency of the second RF signal. The capacitance range of the second tuned variable capacitance circuit is smaller than the capacitance range of the first tuned variable capacitance circuit. The second load variable capacitance circuit is connected to the ground reference terminal and configured to fine tune an impedance of the transformer-coupled capacitive tuning matching network. The capacitance range of the second load variable capacitance circuit is smaller than the capacitance range of the first load variable capacitance circuit. The method further includes performing an etch process, adjusting a capacitance of at least one of the second tuned variable capacitance circuit or the second load variable capacitance circuit for a deposition process, and performing a deposition process.

[0022] In some embodiments, the rapid alternating processing method further includes repeatedly switching between the etch process and the deposition process, and setting the second tuned variable capacitance circuit to be in a first state during the etch process and to be in a second state during the deposition process.

[0023] In some embodiments, the rapid alternating processing method further includes repeatedly switching between the etch process and the deposition process, and setting the second load variable capacitance circuit to be in a first state during the etch process and to be in a second state during the deposition process.

[0024] In some embodiments, the rapid alternating processing method further includes repeatedly switching between the etch process and the deposition process, and changing a state of the second tuned variable capacitance circuit and a state of the second load variable capacitance circuit during the transition between the etch process and the deposition process.

[0025] In some embodiments, the rapid alternating processing method further includes measuring a phase and a magnitude of the first RF signal, and adjusting at least one of a capacitance of the first tunable capacitance circuit or a capacitance of the first variable load capacitance circuit based on the phase and magnitude of the first RF signal.

[0026] In some embodiments, the rapid alternating processing method further includes repeatedly switching between the etch process and the deposition process, and controlling states of the first relay and the second relay to be in a first state during the etch process and to be in a second state during the deposition process. The second tuneable variable capacitance circuit includes a first relay. The first relay is configured to switch between the first capacitance and the second capacitance. The second load variable capacitance circuit includes a second relay. The second relay is configured to switch between a third capacitance and a fourth capacitance.

[0027] In some embodiments, the rapid alternating processing method further includes transitioning the first relay between the first capacitance and the second capacitance when transitioning between the etch process and the deposition process, and refraining from transitioning the second relay between the third capacitance and the fourth capacitance when transitioning between the etch process and the deposition process.

[0028] In some embodiments, the rapid alternating processing method further includes transitioning the first relay between a first capacitance and a second capacitance when transitioning between the etch process and the deposition process, and transitioning the second relay between a third capacitance and a fourth capacitance when transitioning between the etch process and the deposition process.

[0029] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0030] The present disclosure will become more fully understood from the detailed description and the accompanying drawings. [Brief description of the drawings]

[0031] [Figure 1] FIG. 2 is a functional block diagram of an example of a substrate processing system incorporating a TCP circuit, including a velocity-distributed capacitance circuit, and an RF power ratio switching system, in accordance with some embodiments of the present disclosure.

[0032] [Diagram 2] FIG. 2 is a functional block diagram of an example of the TCP circuit of FIG. 1 including a TCCT matching network with a velocity-distributed capacitance circuit, in accordance with some embodiments of the present disclosure.

[0033] [Diagram 3] 3 is a schematic diagram of the TCP circuit of FIG. 2 in accordance with some embodiments of the present disclosure.

[0034] [Figure 4] 1 is an exemplary Smith chart illustrating impedance points for an etch process and a deposition process, respectively, of a rapid alternating process according to some embodiments of the present disclosure.

[0035] [Figure 5A] 1 illustrates a substrate processing method including a rapid alternating process including fast impedance tuning according to some embodiments of the present disclosure. [Figure 5B] 1 illustrates a substrate processing method including a rapid alternating process including fast impedance tuning according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] In the drawings, reference numbers may be reused to identify similar and / or equivalent elements.

[0037] A conventional TCCT matching network may include a load capacitor and a tuning capacitor. The load capacitor is connected to a ground reference and is used to compensate for changes in the load impedance. The tuning capacitor is used to adjust the frequency of the RF power supplied to the TCP reactor coil. Both the load capacitor and the tuning capacitor include a stationary electrode and a movable electrode. The TCP reactor coil may include an inner coil and an outer coil. The inner coil is disposed within the outer coil. The ratio of the power supplied to the inner coil to the power supplied to the outer coil is adjusted by moving the movable electrode of the capacitor. The movable electrode may be moved via mechanical components such as a lead screw, a cam, a cam follower, a bracket, a counterbalance, and a motor (e.g., a linear motor and / or a rotary motor). Conventional techniques for moving the movable electrode are too slow to meet the speed requirements for rapid alternating processes (RAP), which include rapidly switching between etch and deposition processes. The duration of each etch and deposition process may be less than 1 second, and the speed requirement to transition between two impedance states (one impedance state for etch and another impedance state for deposition) may be less than 0.1 seconds.

[0038] For RAP, such as the Bosch process, which includes deep silicon etching, there are two etch and deposition tuning points for the TCCT matching network. The first tuning point is for etch and the second tuning point is for deposition. The two tuning points refer to two impedance configurations of the matching network, each impedance configuration having its own tuning capacitance and load capacitance. Because traditional TCCT matching networks were not quick enough to transition between the two tuning points, a midpoint between the two tuning points is often selected in an attempt to meet both the etch and deposition requirements. The frequency of the generated RF signal is then adjusted via the RF generator as opposed to adjusting the capacitance of the tuning capacitor of the TCCT matching network. However, sometimes this approach does not meet the frequency and reflected power requirements of the TCCT matching network for both the etch and deposition processes, for example.

[0039] Examples described herein include a TCCT matching network that can rapidly transition between different impedance states for both the tuning circuit and the load circuit of the TCCT matching network. The tuning circuit adjusts the frequency of the RF signal output from the TCCT matching network. The load circuit is used to adjust the impedance of the TCCT matching network and compensate for load changes during the etch and deposition processes. The load changes may be due to changes in process gas type, process gas pressure, and / or power settings. The rapid transition meets the frequency and reflected power requirements for both the etch and deposition processes.

[0040] Each of the TCCT matching networks includes a coarse tuning circuit and a fine tuning circuit, the coarse tuning circuit including a coarse tuning and load capacitance circuit for coarsely setting the tuning and load impedance parameters of the TCCT matching network, and the fine tuning circuit including a fine tuning and load capacitance circuit for finely setting the tuning and load impedance parameters of the TCCT matching network.

[0041] In one embodiment, two tuning points close to each other are selected, one for the RAP etch and the other for the deposition. For example, the tuning capacitance for the etch may be within a first predetermined range of the tuning capacitance for the deposition (e.g., 5-50 picofarads (pF)). Similarly, the load capacitance for the etch may be within a second predetermined range of the load capacitance for the deposition (e.g., 5-100 pF). Other predetermined ranges may be implemented. The predetermined ranges may be different or the same. Also, the predetermined range for tuning may be smaller or larger than the predetermined range for the load.

[0042] Prior to or during the RAP, the coarse tuning and load capacitance are preset and fixed to be the same for both the etch and deposition processes. The capacitance of the coarse tuning and load capacitance circuits is not adjusted during the RAP. The fine tuning and load capacitance of the fine tuning and load capacitance circuits may be preset and / or adjusted during the RAP. The capacitance range of the fine tuning capacitance circuit is the smaller (or a percentage) of the coarse tuning capacitance circuit. Similarly, the capacitance range of the fine load capacitance circuit is the smaller (or a percentage) of the coarse load capacitance circuit. In one embodiment, the difference in capacitance of the tuning adjustment circuit for each two tuning points is greater than the difference in capacitance of the load adjustment circuit for each two tuning points. Both tuning points are stable during the entire RAP.

[0043] While traditional TCCT matching networks take more than one second to switch between etch and deposition impedance states, examples disclosed herein, including the one shown in FIG. 3, can reduce the switching time to less than one second, as further described below. The examples include a coarse tuning circuit and a fine tuning circuit. Each of the fine tuning circuits includes a tuning variable capacitance circuit and a variable load capacitance circuit having a capacitance range smaller than the capacitance range of the tuning variable capacitance circuit and the load capacitance circuit of the corresponding one of the coarse tuning circuits. The capacitance of the fine tuning circuit can be quickly switched between different capacitances due to the corresponding capacitance range of the fine tuning circuit and the corresponding circuitry for controlling the transition between different capacitance states. Another advantage of the embodiment of FIG. 3 is the precision of the tuning / switching compared to existing mechanical systems. The fine tuning circuit includes a relay for fast and accurate switching between different capacitance states.

[0044] 1 shows a substrate processing tool 100 incorporating an exemplary TCP circuit 101 and an RF power ratio switching system 102. The TCP circuit 101 includes a TCP reactor coil 104, a TCCT coil current adjustment circuit 105, a TCCT coil output circuit 106, and a TCCT matching network 107. The RF power ratio switching system 102 includes the TCCT matching network 107, a first RF generator 108, and a controller 110. The TCCT matching network 107 includes a speed positioning capacitance circuit 112 used for tuning the TCCT matching network 107 and for rapid fine tuning adjustment of the capacitance of the load capacitance circuit. An example of the tuning and load capacitance circuit is shown in FIG. 3.

[0045] The substrate processing tool 100 further includes a plasma processing chamber 113. The TCP reactor coil 104 is disposed outside and above the plasma processing chamber 113. A first RF generator 108 provides a first RF source signal. A TCCT (or first) matching network 107 is included between the first RF generator 108 and the TCP reactor coil 104. The TCCT matching network 107 allows tuning of the power provided to the TCP reactor coil 104.

[0046] The plasma processing chamber 113 includes a ceramic window 120 located adjacent to the TCP reactor coil 104 and allowing efficient transmission of a first RF source signal into the plasma processing chamber 113 for plasma generation purposes. A substrate support 121, such as an electrostatic chuck, pedestal or other suitable substrate support, is disposed at the bottom of the plasma processing chamber 113. The substrate support 121 supports a substrate 122. When the substrate support 121 is an electrostatic chuck, the substrate support 121 includes conductive portions 124 and 126 that are electrically insulated from one another. The substrate support 121 is surrounded by an insulator 128 and is capacitively coupled to the substrate 122. By applying a DC voltage across the conductive portions 124, 126, a capacitive coupling is created between the conductive portions 124, 126 and the substrate 122. This capacitive coupling attracts the substrate 122 to the substrate support 121.

[0047] The plasma processing tool 100 further includes a bias RF generator 130 connected to a bias (or second) matching network 132. The second matching network 132 is connected between the bias RF generator 130 and the substrate support 121. The second matching network 132 matches the impedance (e.g., 50Ω) of the bias RF generator 130 to the impedance of the substrate support 121 and the plasma 134 in the plasma processing chamber 113 as seen by the second matching network 132. The controller 110 controls the operation of the RF generators 108, 130 based on a recipe and the output of one or more sensors, such as a voltage sensor, a current sensor, a phase sensor, etc. Exemplary sensors are shown in FIG. 3. In some embodiments, the controller 110 is implemented as two or more controllers.

[0048] In operation, an ionizable gas flows into the plasma processing chamber 113 through the gas inlet 156 and exits the plasma processing chamber 113 through the gas outlet 158. A first RF signal is generated by the RF generator 108 and sent to the TCP reactor coil 114. The first RF signal radiates from the TCP reactor coil 104 through the window 120 into the plasma processing chamber 113. This causes the gas in the plasma processing chamber 113 to ionize and form a plasma 134. The plasma 134 creates a sheath 160 along the walls of the plasma processing chamber 113. The plasma 134 includes electrons and positively charged ions. Being much lighter than the positively charged ions, the electrons tend to move more easily, creating a DC bias voltage and a DC sheath potential at the inner surfaces of the plasma processing chamber 113. The average DC bias voltage and DC sheath potential at the substrate 122 affect the energy with which the positively charged ions strike the substrate 122. This energy affects process characteristics, such as the rate at which etching or deposition occurs.

[0049] The controller 110 may adjust the bias RF signal generated by the RF generator 130 to change the amount of DC bias and / or DC sheath potential near / at the substrate 122. The controller 110 may compare the output of the sensor and / or a representative value derived based on the output to one or more set point values. The set point values ​​may be predetermined and stored in the memory 162 of the controller 110. The bias RF signal may be adjusted based on the difference between (i) the output and / or representative value of the sensor and (ii) another set point value. The bias RF signal passes through a bias matching network 132. The output provided by the bias matching network 132 (referred to as a matched signal) is then passed to the substrate support 121. The bias RF signal passes through an insulator 128 to the substrate 122.

[0050] Figure 2 shows a TCP circuit 101 including the TCP reactor coil 104 (shown as inner coils L1, L2 and outer coils L3, L4) of Figure 1, the TCCT coil current conditioning circuit 105, the TCCT coil output circuit 106, and the TCCT matching network 107. The inner coils L1, L2 and outer coils L3, L4 may be of helical shape as shown, or may have different shapes and / or configurations.

[0051] The TCCT coil current conditioning circuit 105 is connected to the inner coils L1, L2 at coil ends D and E, and to the outer coils L3, L4 at coil ends B and G. The TCCT coil output circuit 106 is connected to the inner coils L1, L2 at coil ends C and F, and to the outer coils L3, L4 at coil ends A and H. The TCCT coil current conditioning circuit 105 receives power from an RF generator 108 connected to a reference terminal (or ground reference terminal) 220. The TCCT coil output circuit 106 is connected to the ground reference terminal 220.

[0052] The TCCT matching network 107 includes a velocity configuration capacitance circuit 112 that adjusts the frequency and / or RF power supplied to the coils L1-L4 from the TCCT coil current adjustment circuit 105. Changing the RF power changes the RF power ratio between the inner coils L1, L2 and the outer coils L3, L4. The controller 110 is connected to the velocity configuration capacitance circuit 112 and adjusts its capacitance to adjust the frequency, the supplied RF power, and the RF power ratio.

[0053] 3 shows a TCP circuit 101 including a TCCT matching network 107 configured to match the impedance downstream from the TCCT matching network 107 to the impedance upstream from the TCCT matching network, typically their impedance is about 50 ohms (Ω). This is done to minimize the amount of reflected power to the RF generator 108. The TCCT matching network 107 includes a coarse tuning circuit 300 and a fine tuning circuit 302. The coarse tuning circuit 300 includes a first tuning variable capacitance circuit 304 and a first load variable capacitance circuit 306. The fine tuning circuit 302 includes (i) a second tuning variable capacitance circuit 308 connected in parallel with the first tuning variable capacitance circuit 304, and (ii) a second load variable capacitance circuit 310 connected in parallel with the first load variable capacitance circuit 306. The speed-distributed capacitance circuit 112 of FIGS.

[0054] The first tuned variable capacitance circuit 304 includes a first coarse-tuned variable capacitor C1 and may include one or more additional capacitors (e.g., capacitor C2 is shown connected in parallel with capacitor C1). The first coarse-tuned variable capacitance circuit 306 includes a first coarse-load variable capacitor C3 and may include one or more additional capacitors (e.g., capacitor C4 is shown connected in parallel with capacitor C3). In one embodiment, one or more of capacitors C2 and C4 are not included. The capacitances of capacitors C1, C3 are adjusted by the controller 110 via respective motors 311, 313. Capacitors C1, C3 may have stationary electrodes and movable electrodes. The movable electrodes move relative to the stationary electrodes via motors 311, 313.

[0055] The second tuned variable capacitance circuit 308 (also referred to as the first speed arrangement capacitance circuit) includes a first relay 312, a fixed capacitor C5, and a variable capacitor C6. The variable capacitance range of the second tuned variable capacitance circuit 308 is smaller than (or a portion of) the variable capacitance range of the first tuned variable capacitance circuit 304. The fixed capacitor C5 is connected in series with the variable capacitor C6. The capacitor C5 and / or the capacitor C6 are connected in parallel with the capacitors C1, C2 via a switch S1 of the first relay 312. The first relay 316 includes a first inductor (or coil) L5, which when powered switches the switch S1 between (i) a first state that connects the capacitor C5 in parallel with the capacitors C1, C2, and (ii) a second state that connects the collective series of capacitors C5 and C6 in parallel with each of the capacitors C1, C2. In one embodiment, when performing an etch process, capacitor C5 is connected in parallel with capacitors C1 and / or C2, and when performing a deposition process, both capacitors C5, C6 are connected in parallel with capacitors C1 and / or C2. In another embodiment, when performing a deposition process, capacitor C5 is connected in parallel with capacitors C1 and / or C2, and when performing an etch process, both capacitors C5, C6 are connected in parallel with capacitors C1 and / or C2.

[0056] The second load variable capacitance circuit 310 (also referred to as the second speed arrangement capacitance circuit) includes a second relay 314, a fixed capacitor C7, and a variable capacitor C8. The variable capacitance range of the second load variable capacitance circuit 310 is smaller than (or a portion of) the variable capacitance range of the first load variable capacitance circuit 306. The fixed capacitor C7 is connected in series with the variable capacitor C8. The capacitor C7 and / or the capacitor C8 are connected in parallel with the capacitors C3, C4 via a switch S2 of the second relay 314. The second relay 314 includes a second inductor (or coil) L6, which when powered, switches the switch S2 from (i) a first state that connects the capacitor C7 in parallel with the capacitors C3, C4, and (ii) a second state that connects the collective series of capacitors C7 and C8 in parallel with each of the capacitors C3, C4. The capacitors C3, C4 and the switch S2 are connected to the ground reference terminal 220. In one embodiment, when performing an etch process, capacitor C7 is connected in parallel with capacitors C3 and / or C4, and when performing a deposition process, both capacitors C7, C8 are connected in parallel with capacitors C3 and / or C4. In another embodiment, when performing a deposition process, capacitor C7 is connected in parallel with capacitors C3 and / or C4, and when performing an etch process, both capacitors C7, C8 are connected in parallel with capacitors C3 and / or C4. The switches S1, S2 of the relays 312, 314 can be switched in less than 0.2 milliseconds (ms).

[0057] The TCCT matching network 107 further includes a first sensor 320 that detects the phase and magnitude of the RF signal generated by the RF generator 108. The controller 110 may adjust the capacitance of the capacitors C1, C3 and adjust the capacitance of C6, C8 based on the output of the first sensor 320.

[0058] The TCCT matching network 107 is connected to the TCCT coil current adjustment circuit 105 through an inductor L7. Capacitors C1 and C2 are connected in series with the inductor L7 between the sensor 320 and the TCCT current adjustment circuit 105. Capacitors C3 and C4 are connected in series with the inductor L7 between the ground reference terminal 220 and the TCCT current adjustment circuit 105.

[0059] The TCCT coil current adjustment circuit 105 includes a variable capacitor C9, a second sensor 330, another variable capacitor C10, and a third sensor 332. The second sensor is connected in series with the variable capacitor C9 between the inductor L7 (or the output of the TCCT matching network 107) and the inner coils L1, L2. The third sensor is connected in series with the variable capacitor C10 between the inductor L7 and the outer coils L3, L4. The sensors 330, 332 measure the current through the capacitors C9, C10. The controller 110 adjusts the capacitance of C9, C10 based on the amount of current supplied through C9, C10 to the inner coils L1, L2 and the outer coils L3, L4.

[0060] The TCCT coil output circuit 106 includes capacitors C11-C14, each connected to the coils L1-L4 and to the ground reference terminal 220. Each of the capacitors C11-C14 is connected in series with a respective one of the coils L1-L4 and is connected to the ground reference terminal 220.

[0061] FIG. 4 shows an exemplary Smith chart illustrating two exemplary impedance points for an etch process and a deposition process, respectively, of a rapid alternating process. A first tuning point A is shown for one of the etch process and the deposition process, and a second tuning point B is shown for the other one of the etch process and the deposition process. In the exemplary method of FIG. 5, a RAP is performed that includes repeatedly switching between performing an etch process and performing a deposition process. The controller 110 of FIGS. 1-3 changes the state of the rate placement capacitance circuit 112 (or 308, 310) for the etch process and the deposition process. In one embodiment, the controller 110 changes the state of the second tuning variable capacitance circuit 308 when switching between the etch state and the deposition state, and does not change the state of the second load variable capacitance circuit 310. In another embodiment, the controller 110 changes the state of both the variable capacitance circuits 308, 310 when switching between the etch state and the deposition state. The Smith chart includes real and imaginary axes for resistance, with the center of the Smith chart being the 50 Ω point. Points A and B are shown as examples. The location of points A and B on the Smith chart may differ from that shown. Also, the distance between points A and B may differ from that shown.

[0062] 5A-5B illustrate an exemplary substrate processing method including a rapid alternating process that includes fast impedance tuning. The following operations may be performed iteratively and are described primarily with respect to the implementation of FIGS. 1-4. The method may begin at 500. At 501, a substrate may be placed on the substrate support 121. At 502, the controller 110 obtains a recipe.

[0063] At 504, the controller 110 sets the initial tuning and load points or adjusts the tuning and load points based on the recipe. This may include setting the coarse tuning and load capacitances of the capacitors C1 and C3. The controller 110 may also set the capacitances of the capacitors C6, C8 of the variable capacitance circuits 308, 310. For example, the type of process gas, gas pressure, and RF power parameters of the recipe have associated loads. The capacitances of the capacitors C3, C8 may be set to compensate for the loads associated with the gas, gas pressure, and RF power parameters in the recipe for minimum reflected power.

[0064] At 506, the controller 110 may detect, via the sensor 320, the phase and magnitude of the RF power signal output from the RF generator 108. At 508, the controller 110 may determine whether the settings of C1, C3, C6, C8 are appropriate for the measured phase and magnitude of the RF power signal. This may include, for example, looking up values ​​for C1, C3, C6, C8 in a look-up table (LUT) stored in the memory 162. If the settings of C1, C3, C6, and C8 match the looked-up values, a RAP process may be performed; otherwise, at 504, the capacitance of one or more of the capacitors C1, C3, C6, C8 may be adjusted.

[0065] The RAP process involves repeatedly switching between performing an etch process and performing a deposition process. The RAP process may include hundreds of etch and deposition processes, with each etch process removing a thin layer of material within a feature (e.g., a hole or trench). Each etch process may remove a predetermined number of micrometers (μm) of material. By performing multiple etch and deposition processes to form a feature, the amount of "bow" of the sidewalls of the feature is minimized. Each deposition process provides a chemically inert passivation layer that minimizes etching of the sidewalls during subsequent etch processes. The etch process may be a nearly isotropic plasma etch process, which involves etching primarily at the bottom of the feature, rather than along the sides of the feature. The RAP process may begin at 510.

[0066] At 510, the controller 110 sets the state of the fine tuning and load variable capacitance circuits 308, 310 for the etch process based on the portion of the recipe related to the etch process. The state may be set based on the type of process gas, the gas pressure, the RF power level of the RF generator 108, etc. during the etch process. As an example, sulfur hexafluoride (SF6) may be provided to the processing chamber 113 during the etch process. In one embodiment, the controller 110 also sets and / or changes the state of the variable capacitance circuits 308, 310 based on changing the capacitance of the capacitors C9, C10, which may be changed during operation 530, for example. This may be performed to minimize RF reflected power.

[0067] At 512, the controller 110 sets process parameters for the etch process. This may include supplying a gas, such as SF6, setting the chamber pressure, gas flow rates, temperature, etc. for the etch process. At 514, the controller 110 performs the etch process. At 516, the controller 110 determines whether the etch process is complete. If yes, operation 518 may be performed.

[0068] At 518, the controller 110 determines whether the current etch process is the last etch process and there are no further deposition processes to be performed. If no, operation 520 is performed; otherwise, the method may end at 538.

[0069] In 520, the controller 110 sets the state of the fine tuning and load variable capacitance circuit 308, 310 for the deposition process based on the portion of the recipe related to the deposition process. The state may be set based on the process gas, chamber pressure, gas pressure, RF power level of the RF generator 108, etc. during the deposition process. As an example, octafluorocyclobutane (C4F8) may be provided to the processing chamber 113 during the deposition process. The state of the fine tuning and load variable capacitance 308, 310 may be changed by changing the state of the switches S1, S2. In one embodiment, the controller 110 also sets and / or changes the state of the variable capacitance circuit 308, 310 based on the change in capacitance of the capacitors C9, C10, which may be changed during operation 530, for example. This may be performed to minimize RF reflected power.

[0070] The controller 110 may determine whether to change the state of switch S2 based on the detected and / or determined amount of load change. For example, if the gas, gas pressure, and / or RF power levels are changed and thus a change in the state of the fine-load variable capacitance circuit 310 is appropriate, the state of switch S2 is changed for the deposition process. If the change in load is minimal between the etch and deposition processes, the controller 110 may refrain from changing the state of switch S2.

[0071] At 522, the controller 110 sets process parameters for the deposition process. This may include supplying a gas, such as C4F8, setting the chamber pressure, gas flow rates, temperature, etc., for the deposition process. At 524, the controller 110 performs the deposition process. At 526, the controller 110 determines whether the deposition process is complete. If yes, operation 528 may be performed.

[0072] At 528, the controller 110 may determine whether to perform another iteration of the RAP. If yes, operation 510 may be performed; otherwise, the method may end at 538.

[0073] The following operations 530, 532, 534, 536 may be performed prior to and / or during the RAP. Operations 530 532, 534, 536 may be performed in parallel with the operation of the RAP. In 530, the controller 110 may set an initial capacitance of the current adjustment capacitances C9, C10 or adjust the capacitance of the current adjustment capacitances C9, C10 for the etch or deposition process being performed. In one embodiment, the capacitance of the capacitors C9, C10 is adjusted such that the current flow through one of the capacitors C9, C10 is increased while the current flow through the other one of the capacitors C9, C10 is decreased. This is done to minimize the amount of reflected power.

[0074] At 532, the controller 110 detects the current levels in the inner coils L1, L2 and the outer coils L3, L4 via the sensors 330, 332. By detecting the current levels through the capacitors C9, C10, the controller 110 can estimate the current levels in the inner coils L1, L2 and the outer coils L3, L4 based on the known inductances of the coils L1-L4 and the capacitances of the capacitors C11-C14.

[0075] At 534, the controller 110 determines whether the current levels in the coils L1-L4 are within a predetermined range of the target level. If yes, operation 536 may be performed, otherwise operation 530 may be performed. At 536, the controller 110 determines whether the RAP is complete. If yes, the method may end at 538, otherwise operation 532 may be performed.

[0076] The operations described above are intended to be illustrative examples. The operations may be performed sequentially, synchronously, simultaneously, consecutively, during overlapping time periods, or in a different order depending on the application. Also, any of the operations may not be performed or may be skipped depending on the implementation and / or sequence of events.

[0077] The above description is merely exemplary in nature and in no way limits the disclosure, its applications, or uses. The broad teachings of the disclosure may be implemented in various forms. Thus, while the disclosure includes certain examples, the true scope of the disclosure should not be so limited, as other modifications will become apparent upon review of the drawings, specification, and claims that follow. It should be understood that one or more steps in a method may be performed in a different order (or in parallel) without altering the principles of the disclosure. Furthermore, although each of the embodiments has been described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure may be implemented in and / or combined with any feature of any of the other embodiments, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and substituting one or more of the embodiments with each other remains within the scope of the disclosure.

[0078] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using a variety of terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." Unless explicitly described as being "direct," when a relationship between a first element and a second element is described in the above disclosure, the relationship may be a direct relationship, where there are no other intervening elements between the first element and the second element, but it may also be an indirect relationship, where there are one or more intervening elements (either spatially or functionally) between the first element and the second element. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical non-exclusive OR (A OR B OR C), and not to mean "at least one of A, at least one of B, and at least one of C."

[0079] In some implementations, the controller is part of a system, which may be part of the examples described above. Such a system may comprise semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more platforms, and / or specific processing components (wafer pedestals, gas flow systems, etc.) for processing. These systems may be integrated with electronic circuitry for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronic circuitry may be referred to as a "controller," which may control various components or sub-portions of one or more systems. The controller may be programmed to control any of the processes disclosed herein, including delivery of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow settings, fluid delivery settings, position and operation settings, wafer transfer in and out of tools and other transfer tools and / or load locks connected to or interfaced with a particular system, depending on the processing requirements and / or type of system.

[0080] In general, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receives instructions, issues instructions, controls operations, enables cleaning operations, enables endpoint measurements, and the like. Integrated circuits may include firmware that stores program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or chips in the form of one or more microprocessors or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing a particular process on or for a semiconductor wafer or for a system. The operational parameters may, in some embodiments, be part of a recipe defined by a process engineer to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0081] The controller, in some implementations, may be part of or coupled to a computer that is integrated with, coupled to, or otherwise networked to the system, or a combination thereof. For example, the controller may be in the "cloud" or in all or part of a fab host computer system that may enable remote access of wafer processing. The computer may enable remote access to the system to monitor the current progress of a fabrication operation, examine the history of past fabrication operations, and examine trends or performance metrics from multiple fabrication operations in order to change parameters of a current process, set up processing steps subsequent to a current process, or initiate a new process. In some examples, a remote computer (e.g., a server) may provide process recipes to the system over a network that may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings that are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data that specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by having one or more individual controllers networked together and working toward a common purpose, such as the process and control described herein. One example of a distributed controller for such purposes would be one or more integrated circuits on the chamber in communication with one or more remotely located integrated circuits (such as at the platform level or as part of a remote computer) combined to control the process on the chamber.

[0082] Without being limited thereto, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin clean chamber or module, a metal plating chamber or module, a clean chamber or module, a chamfer edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing system that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0083] As described above, depending on the process step or steps to be performed by the tool, the controller may communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used in material transfers carrying containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

Claims

1. A transformer-coupled capacitive tuned coupling network comprising: a coarse adjustment circuit configured to receive a first radio frequency (RF) signal, a first tuned variable capacitance circuit configured to adjust a frequency of the first RF signal to generate a second RF signal; a first load variable capacitance circuit connected to a ground reference terminal and configured to adjust the impedance of the transformer coupled capacitive tuned matching network; a coarse adjustment circuit comprising: a second tuned variable capacitance circuit configured to fine tune a frequency of the second RF signal, the second tuned variable capacitance circuit having a capacitance range smaller than a capacitance range of the first tuned variable capacitance circuit; a second load variable capacitance circuit connected to the ground reference terminal and configured to fine tune the impedance of the transformer coupled capacitive tuning network, the second load variable capacitance circuit having a capacitance range smaller than a capacitance range of the first load variable capacitance circuit; A fine adjustment circuit comprising: A transformer coupled capacitive tuned coupling network comprising:

2. 2. The transformer-coupled capacitive tuning network of claim 1, the second tunable variable capacitance circuit is connected in parallel with the first tunable variable capacitance circuit; the second load variable capacitance circuit is connected in parallel with the first load variable capacitance circuit; Transformer-coupled capacitive tuned coupling network.

3. 2. The transformer-coupled capacitive tuning network of claim 1, the first tuned variable capacitance circuit comprises a first variable capacitor; the second tuned variable capacitance circuit comprises a second variable capacitor connected in parallel with the first variable capacitor; the first load variable capacitance circuit comprises a third variable capacitor; the second load variable capacitance circuit comprises a fourth variable capacitor connected in parallel with the third variable capacitor; Transformer-coupled capacitive tuned coupling network.

4. 2. The transformer-coupled capacitive tuning network of claim 1, the first tuned variable capacitance circuit comprises a first variable capacitor; the second tuned variable capacitance circuit comprises a first plurality of capacitors connected in parallel with the first variable capacitor; the first load variable capacitance circuit comprises a second variable capacitor; the second load variable capacitance circuit comprises a second plurality of capacitors connected in parallel with the second variable capacitor; Transformer-coupled capacitive tuned coupling network.

5. 5. The transformer-coupled capacitive tuning network of claim 4, the second tuned variable capacitance circuit comprises a third variable capacitor connected in series with the first fixed capacitor; the second load variable capacitance circuit comprises a fourth variable capacitor connected in series with a second fixed capacitor; Transformer-coupled capacitive tuned coupling network.

6. 2. The transformer-coupled capacitive tuning network of claim 1, a first motor configured to vary the capacitance of the first tuned variable capacitance circuit; a second motor configured to vary the capacitance of the first load variable capacitance circuit; a first relay configured to vary the capacitance of the second tuned variable capacitance circuit; a second relay configured to change the capacitance of the second load variable capacitance circuit; a transformer coupled capacitive tuned coupling network further comprising:

7. 1. A system comprising: A transformer-coupled capacitive tuning and matching network according to claim 1; One or more controllers, performing a rapid alternating process that includes repeatedly switching between an etch process and a deposition process; setting the trim circuit to be in a first state during the etch process and to be in a second state during the deposition process; one or more controllers configured to: A system comprising:

8. 8. The system of claim 7, wherein the one or more controllers are configured to change a state of at least one of the second tuned variable capacitance circuit or the second load variable capacitance circuit during a transition between the etch process and the deposition process.

9. 8. The system of claim 7, further comprising a sensor configured to measure a phase and a magnitude of the first RF signal; the one or more controllers are configured to adjust at least one of a capacitance of the first tuned variable capacitance circuit or a capacitance of the first load variable capacitance circuit based on the phase and magnitude of the first RF signal. system.

10. 2. The transformer-coupled capacitive tuning network of claim 1, the second tuned variable capacitance circuit comprises a first relay; the first relay is configured to switch between a first capacitance and a second capacitance; the second load variable capacitance circuit comprises a second relay; the second relay is configured to switch between a third capacitance and a fourth capacitance; Transformer-coupled capacitive tuned coupling network.

11. 1. A system comprising: A transformer-coupled capacitive tuned coupling network according to claim 10; One or more controllers, performing a rapid alternating process that includes repeatedly switching between an etch process and a deposition process; setting a state of the first relay and a state of the second relay to be in a first configuration during the etch process and to be in a second configuration during the deposition process; one or more controllers configured to: A system comprising:

12. 12. The system of claim 11, wherein the one or more controllers: transitioning the first relay between the first capacitance and the second capacitance when transitioning between the etch process and the deposition process; refraining from transitioning the second relay between the third capacitance and the fourth capacitance when transitioning between the etch process and the deposition process; A system configured to:

13. 12. The system of claim 11, wherein the one or more controllers: transitioning the first relay between the first capacitance and the second capacitance when transitioning between the etch process and the deposition process; transitioning the second relay between the third capacitance and the fourth capacitance when transitioning between the etch process and the deposition process; A system configured to:

14. 1. A rapid alternating processing method comprising: setting a capacitance of a first tuned variable capacitance circuit of a transformer-coupled capacitive tuned coupling network, the first tuned variable capacitance circuit being configured to adjust a frequency of a first radio frequency (RF) signal to generate a second RF signal; setting a capacitance of a first load variable capacitance circuit connected to a ground reference terminal and configured to adjust an impedance of the transformer coupled capacitive tuned matching network; setting a capacitance of the second tune variable capacitance circuit and the second load variable capacitance circuit for an etch process; the second tuning variable capacitance circuit is configured to fine tune a frequency of the second RF signal; a capacitance range of the second tuned variable capacitance circuit is smaller than a capacitance range of the first tuned variable capacitance circuit; the second variable load capacitance circuit is connected to the ground reference terminal and configured to fine tune the impedance of the transformer-coupled capacitive tuning network; the capacitance range of the second load variable capacitance circuit is smaller than the capacitance range of the first load variable capacitance circuit; setting the capacitance of the second tuned variable capacitance circuit and the second load variable capacitance circuit; performing said etch process; adjusting a capacitance of at least one of the second tune variable capacitance circuit or the second load variable capacitance circuit for a deposition process; performing the deposition process; A rapid alternating processing method comprising:

15. 15. The method of rapid alternating processing according to claim 14, comprising: repeatedly switching between the etch process and the deposition process; setting the second tuned variable capacitance circuit to be in a first state during the etch process and to be in a second state during the deposition process; The rapid alternating processing method further comprises:

16. 15. The method of rapid alternating processing according to claim 14, comprising: repeatedly switching between the etch process and the deposition process; setting the second load variable capacitance circuit to be in a first state during the etch process and to be in a second state during the deposition process; The rapid alternating processing method further comprises:

17. 15. The method of rapid alternating processing according to claim 14, comprising: repeatedly switching between the etch process and the deposition process; changing a state of the second tuned variable capacitance circuit and a state of the second load variable capacitance circuit during a transition between the etch process and the deposition process; The rapid alternating processing method further comprises:

18. 15. The method of rapid alternating processing according to claim 14, comprising: Measuring a phase and a magnitude of the first RF signal; adjusting at least one of a capacitance of the first tunable capacitance circuit or a capacitance of the first variable load capacitance circuit based on the phase and magnitude of the first RF signal; The rapid alternating processing method further comprises:

19. 15. The method of rapid alternating processing according to claim 14, comprising: repeatedly switching between the etch process and the deposition process; controlling states of a first relay and a second relay to be in a first state during the etch process and to be in a second state during the deposition process; Further comprising: the second tuned variable capacitance circuit comprises the first relay; the first relay is configured to switch between a first capacitance and a second capacitance; the second load variable capacitance circuit comprises the second relay; the second relay is configured to switch between a third capacitance and a fourth capacitance; Rapid alternating processing method.

20. 20. The rapid alternating processing method of claim 19, comprising: transitioning the first relay between the first capacitance and the second capacitance when transitioning between the etch process and the deposition process; refraining from transitioning the second relay between the third capacitance and the fourth capacitance when transitioning between the etch process and the deposition process; The rapid alternating processing method further comprises:

21. 20. The rapid alternating processing method of claim 19, comprising: transitioning the first relay between the first capacitance and the second capacitance when transitioning between the etch process and the deposition process; transitioning the second relay between the third capacitance and the fourth capacitance when transitioning between the etch process and the deposition process; The rapid alternating processing method further comprises:

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