Reno Technologies, Inc.

Asm America, Inc.

Michael Gilliam Ulrich

Imran Ahmed Bhutta

Ronald Anthony Decker

Tomislav Lozic

Bala Kandampalayam

Chingping Huang

Ching Ping Huang

In one embodiment, an impedance matching network includes variable capacitors. A first variable capacitor has a terminal electrically connected to the RF input. A second variable capacitor has a terminal electrically connected to the RF output. At least one of the variable capacitors is an electrically variable capacitor (EVC). The EVC includes a plurality of parallel-coupled capacitors comprising fine capacitors increasing in capacitance and coarse capacitors having a greater capacitance. A capacitor position for the EVC for enabling an impedance match is determined by a processor using software. An impedance match is enabled by directly switching the electronically variable capacitor to the determined capacitor position.

Impedance matching network and method

In one embodiment, the present disclosure is directed to a method for impedance matching. A matching network includes first and second reactance elements configured to provide variable positions. A first parameter of the matching network is determined based on a detected value. The method determines first two-port parameters from a first one-dimensional array that corresponds to a first portion of the matching network using the first reactance element position, and second two-port parameters from a second one-dimensional array that corresponds to a second portion of the matching network using the second reactance element position. An output parameter is calculated based on the first parameter, the first two-port parameters, and the second two-port parameters. New first and second reactance element positions are determined from a match position table using the calculated output parameter. The method then alters the reactance elements accordingly to reduce a reflected power.

Impedance matching network and method with reduced memory requirements

In one embodiment, the present disclosure is directed to a method for impedance matching. A matching network includes a first reactance element and a second reactance element. A sensor detects a value related to the plasma chamber or the matching network, and a system parameter is determined based on the detected value. For the determined system parameter, an error-related value is calculated for each of a plurality of potential first reactance element positions or for each of a plurality of potential second reactance element positions. A new first reactance element position and a new second reactance element position are calculated based on the error-related values calculated in the prior step. The first reactance element and the second reactance element are then altered to their new positions to reduce a reflected power.

In one embodiment, an RF impedance matching network for a plasma chamber is disclosed. The matching network includes an electronically variable capacitor (EVC) comprising discrete capacitors, each discrete capacitor having a corresponding switching circuit for switching in and out the discrete capacitor to alter a total capacitance of the EVC. Each switching circuit includes a diode operably coupled to the discrete capacitor to cause the switching in and out of the discrete capacitor, and a filter circuit parallel to the diode, the filter comprising a filtering capacitor in series with an inductor.

Filter for impedance matching

In one embodiment, an RF impedance matching network for a plasma chamber is disclosed. The matching network includes an electronically variable capacitor (EVC) comprising discrete capacitors, each discrete capacitor having a corresponding switching circuit for switching in and out the discrete capacitor to alter a total capacitance of the EVC. Each switching circuit comprises at least one switching field-effect transistor (FET) operably coupled to the corresponding discrete capacitor to cause the switching in and out of the discrete capacitor. For each switching circuit, when the switching circuit is switched OFF to switch out the corresponding discrete capacitor, the at least one switching FET receives a bias voltage from a bias voltage source to reduce a capacitance variability of the at least one switching FET.

Switching circuit with voltage bias

In one embodiment, an impedance matching network includes a mechanically variable capacitor (MVC), a second variable capacitor, and a control circuit. The control circuit carries out a first process of determining a second variable capacitor configuration for reducing a reflected power at the RF source output, and altering the second variable capacitor to the second variable capacitor configuration. The control circuit also carries out a second process of determining an RF source frequency, and, upon determining that the RF source frequency is outside, at a minimum, or at a maximum of a predetermined frequency range, determining a new MVC configuration to cause the RF source frequency, according to an RF source frequency tuning process, to be altered to be within or closer to the predetermined frequency range. The determination of the new MVC configuration is based on the RF source frequency and the predetermined frequency range.

In one embodiment, an RF impedance matching network utilizing at least one electronically variable capacitors (EVC) is disclosed. Each EVC includes discrete capacitors operably coupled in parallel, the discrete capacitors including fine capacitors and coarse capacitors. A control circuit determines a parameter related to the plasma chamber and, based on the parameter, determines which of the coarse capacitors and which of the fine capacitors to have switched in to cause an impedance match. The increase of the variable total capacitance of each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in.

RF impedance matching circuit and systems and methods incorporating same

In one embodiment, a phase detection circuit includes a current signal input to receive a current signal indicative of a current amplitude of an RF signal and a voltage signal input to receive a voltage signal indicative of a voltage amplitude of the RF signal. A high-pass filter and a low-pass filter are each configured to filter one of (i) the current signal from the current signal input or (ii) the voltage signal from the voltage signal input, wherein the high-pass filter and the low-pass filter collectively cause a substantially 90 degree offset between a phase angle of the current signal and a phase angle of the voltage signal. A phase difference circuit receives the filtered current signal and the filtered voltage signal to determine a phase angle difference between the current signal and the voltage signal.

Amplitude and phase detection circuit

In one embodiment, the present disclosure is directed to a method for performing diagnostics on a matching network that utilizes an electronically variable capacitor (EVC). According to the method, all the discrete capacitors of the EVC are switched out. At a first node, a parameter associated with a current flowing between a power supply and one or more of the switches of the discrete capacitors is measured. The method then switches in, one at a time, each discrete capacitor of the EVC. Upon the switching in of each discrete capacitor, the method remeasures the parameter at the first node and determines whether a change to the parameter at the first node is within a predetermined range to determine whether the corresponding switch, driver circuit, or filter of the discrete capacitor most recently switch in has failed.

Diagnostics for impedance matching network

In one embodiment, the present disclosure may be directed to an impedance matching network that includes an electronically variable capacitor (EVC). The EVC includes discrete capacitors and corresponding switches, each switch configured to switch in and out one of the discrete capacitors to alter a capacitance of the EVC. The switches are operably coupled to a power supply providing a blocking voltage to the switches. A control circuit determines a blocking voltage value of the power supply. Upon determining the blocking voltage value is at or below a predetermined first level, the control circuit causes a limited altering of the capacitance of the EVC, the limited altering limiting the number or type of discrete capacitors to switch in or out based on the extent to which the blocking voltage value is at or below the first level.

In one embodiment, an RF impedance matching network for a plasma chamber is disclosed. The matching network includes a mechanically variable capacitor (MVC) and a second variable capacitor. A control circuit is configured to carry out a first process for altering the second variable capacitor and the RF source frequency to reduce reflected power. The control circuit is further configured to carry out a second process of, upon determining that the alteration of the RF source frequency has caused the RF source frequency to be outside, at a minimum, or at a maximum of a predetermined frequency range, determining a new MVC configuration to cause the RF source frequency, according to the first process, to be altered to be within or closer to the predetermined frequency range. The new MVC configuration is based on the RF source frequency and the predetermined frequency range.

In one embodiment, an RF impedance matching network for a plasma chamber is disclosed. The matching network includes at least one electronically variable capacitor (EVC), each EVC comprising discrete capacitors each having a corresponding switching circuit. Each switching circuit is configured to switch in and out its corresponding discrete capacitor to alter a total capacitance of the EVC. Each switching circuit include a first diode operably coupled to the discrete capacitor, a capacitor coupled in series with the first diode, and a second diode operably coupled to the discrete capacitor. The second diode parallel to the first diode and the capacitor coupled in series.

In one embodiment, the present disclosure is directed to an RF impedance matching network that includes an RF input coupled to an RF source, an RF output coupled to a plasma chamber, and an electronically variable capacitor (EVC). A first control circuit controls the EVC and is separate and distinct from a second control circuit controlling the RF source. To assist in causing an impedance match between the RF source and the plasma chamber, the first control circuit determines, using a match lookup table with a value based on a detected RF parameter, a new EVC configuration for providing a new EVC capacitance. To further cause the impedance match, the second control circuit alters the variable frequency of the RF source, but operates independently from the first control circuit.

Impedance matching using independent capacitance and frequency control

In one embodiment, the present disclosure is directed to a method for impedance matching. The RF source provides at least two repeating, non-zero pulse levels, including a high-priority pulse level and a low-priority pulse level. The matching network comprises at least one EVC, which comprises discrete capacitors configured to switch in and out to provide a plurality of match configurations. Each EVC has a switching limit comprising a predetermined number of switches in or out of the EVC's discrete capacitors in a prior time interval. Upon determining that switching to a new match configuration would cause an EVC to reach the switching limit, the method determines whether the new match configuration is for the low- or high-priority pulse level. If for the low-priority pulse level, the method prevents the switching of the EVC. If for the high-priority pulse level, the method switches the EVC to the new match configuration.

In one embodiment, an RF impedance matching circuit is disclosed. The matching circuit is coupled between a plasma chamber and an RF source providing an RF signal having a frequency. The matching circuit includes a first electronically variable capacitor having a first variable capacitance and a second electronically variable capacitor having a second variable capacitance. A control circuit determines a first parameter related to the plasma chamber, and then determines, based on the first parameter, a first capacitance value for the first electronically variable capacitor and a second capacitance value for the second electronically variable capacitor. The control circuit then generates a control signal to alter the first variable capacitance and the second variable capacitance accordingly, causing the RF power reflected back to the RF source to decrease while the frequency of the RF source is not altered.

Growing community of inventors

Delran, NJ, United States of America

Michael Gilliam Ulrich