FILTER BOX FOR A SUBSTRATE PROCESSING SYSTEM

A filter module for a substrate processing chamber includes a plurality of exterior panels defining an interior, a plurality of internal panels defining a plurality of compartments within the interior of the filter module, and an adjustable capacitor arranged on a first panel of the plurality of internal panels within a first compartment of the plurality of compartments. The adjustable capacitor is coupled, through the first panel, to a motor located outside of the first compartment, and the adjustable capacitor is configured to receive a radio frequency input signal and provide a radio frequency voltage to the substrate processing chamber based on a position of the motor.

FIELD

The present disclosure relates to a radio frequency (RF) box configured to filter RF interference from signals communicated in a substrate processing system.

BACKGROUND

Substrate processing systems are used to perform treatments such as deposition and etching of film on substrates such as semiconductor wafers. For example, deposition may be performed to deposit conductive film, dielectric film, or other types of film using chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), atomic layer deposition (ALD), plasma enhance ALD (PEALD), and/or other deposition processes. During deposition, the substrate is arranged on a substrate support and one or more precursor gases may be supplied to a processing chamber during one or more process steps. In a PECVD or PEALD process, plasma is used to activate chemical reactions within the processing chamber during deposition.

SUMMARY

A filter module for a substrate processing chamber includes a plurality of exterior panels defining an interior, a plurality of internal panels defining a plurality of compartments within the interior of the filter module, and an adjustable capacitor arranged on a first panel of the plurality of internal panels within a first compartment of the plurality of compartments. The adjustable capacitor is coupled, through the first panel, to a motor located outside of the first compartment, and the adjustable capacitor is configured to receive a radio frequency input signal and provide a radio frequency voltage to the substrate processing chamber based on a position of the motor.

In other features, the adjustable capacitor is configured to provide the radio frequency voltage to filter circuitry within the first compartment and the filter circuitry is configured to provide a filtered RF frequency voltage to the substrate processing chamber. The filter module further includes an insulative spacer provided between the adjustable capacitor and the first panel. The filter module further includes an encoder configured to map a capacitance of the adjustable capacitor to an absolute position of the motor.

In other features, a second panel of the plurality of the internal panels separates the first compartment from a second compartment of the plurality of compartments. A third panel of the plurality of the internal panels separates the second compartment from a third compartment of the plurality of compartments. At least one of the second compartment and the third compartment includes filter circuitry configured to filter a heater power signal and provide the filtered heater power signal to the substrate processing chamber.

In other features, the plurality of exterior panels includes a front panel, a back panel, a top panel, a bottom panel, and first and second side panels. The filter module is rectangular and includes a notched corner, and wherein the motor is arranged within the notched corner. The first side panel includes an input connector configured to receive a cable connector and the input connector is configured to receive the radio frequency input signal via the cable connector. A leaf spring is arranged on the first side panel between the input connector and the cable connector and the cable connector connects to the input connector through an opening in the leaf spring. A first end of the leaf spring is mounted on the first side panel and a second end of the leaf spring extends past a perimeter of the first side panel.

In other features, the second end of the leaf spring extends over a contact switch arranged on the back panel of the filter module. Connecting the cable connector to the input connector causes the second end of the leaf spring to engage the contact switch. The contact switch is configured to generate a signal indicating whether at least one of the filter module is installed on the substrate processing chamber and the cable connector is connected to the input connector. The first side panel includes a removable access panel and the first end of the leaf spring is mounted to the first side panel through the removable access panel.

In other features, a substrate processing tool includes a plurality of substrate processing chambers and a plurality of the filter modules. Each of the plurality of filter modules is mounted on a respective one of the plurality of processing chambers. Each of the filter modules includes a removable side panel, and wherein the removable side panel of each of the filter modules faces an outer perimeter of the substrate processing tool.

A filter module for a substrate processing chamber includes a plurality of exterior panels defining an interior, a plurality of internal panels defining a plurality of compartments within the interior of the filter module, and an adjustable capacitor arranged on a first panel of the plurality of internal panels within a first compartment of the plurality of compartments. The adjustable capacitor is coupled, through the first panel, to a motor located outside of the first compartment, and the adjustable capacitor is configured to receive a radio frequency input signal and provide a radio frequency voltage to the substrate processing chamber based on a position of the motor. The adjustable capacitor is configured to provide the radio frequency voltage to filter circuitry within the first compartment and the filter circuitry is configured to provide a filtered RF frequency voltage to the substrate processing chamber. Second and third compartments of the plurality of compartments each include respective circuitry.

DETAILED DESCRIPTION

A substrate processing system may include one or more radio frequency (RF) filter modules (e.g., filter boxes) enclosing RF filter and/or tuning circuits configured to filter RF noise from electrical signals communicated to and from components within the substrate processing system. The filter box may be arranged on or adjacent to and/or integrated with a wall of a processing chamber. For example, the filter box may be arranged on a lower surface of the processing chamber. Service, installation, and/or adjustment of internal filter circuitry of the filter box may be difficult.

A filter box according to the principles of the present disclosure has an improved geometry and arrangement of external and internal features to facilitate installation and removal of the filter box to and from the processing chamber. Further, the filter box is configured to facilitate service and replacement of internal components (e.g., filter circuitry, such as filter printed circuit boards (PCBs), motors, capacitors, etc.) and adjustment of filtering parameters (e.g., using an adjustable capacitor).

Referring now toFIG. 1, an example of a substrate processing system100according to the principles of the present disclosure is shown. While the foregoing example relates to PECVD systems, other plasma-based substrate processing chambers may be used. The substrate processing system100includes a processing chamber104that encloses other components of the substrate processing system100. The substrate processing system100includes an upper electrode108and a substrate support such as a pedestal112including a lower electrode116. Although shown as a single lower electrode116, the lower electrode116may correspond to two or more electrodes arranged in different zones of the pedestal112. A substrate120is arranged on the pedestal112between the upper electrode108and the lower electrode116.

For example only, the upper electrode108may include a showerhead124that introduces and distributes process gases. Alternately, the upper electrode108may include a conducting plate and the process gases may be introduced in another manner. The lower electrode116may be arranged in a non-conductive pedestal. Alternately, the pedestal112may include an electrostatic chuck that includes a conductive plate that acts as the lower electrode116.

A radio frequency (RF) generating system126generates and outputs an RF voltage to the upper electrode108and/or the lower electrode116when plasma is used. In some examples, one of the upper electrode108and the lower electrode116may be DC grounded, AC grounded, or at a floating potential. For example only, the RF generating system126may include one or more RF voltage generators128(e.g., a capacitively-coupled plasma RF power generator, a bias RF power generator, and/or other RF power generator) such as a first RF generator128-1and a second RF generator128-2that generate RF voltages, which are fed by one or more matching and distribution networks130to the lower electrode116(e.g., via a first matching network130-1) and the upper electrode108(e.g., via a second matching network130-2).

The first RF generator128-1provides an RF and/or bias voltage to the lower electrode116. The lower electrode116(which, in some examples, may comprise multiple electrodes) may receive power alternatively or additionally from other power sources, such as a power source132. The second RF generator128-2may provide an RF voltage or may simply connect the upper electrode108to a ground reference.

An example gas delivery system140includes one or more gas sources144-1,144-2, . . . , and144-N (collectively gas sources144), where N is an integer greater than zero. The gas sources144supply one or more gases (e.g., precursors, inert gases, etc.) and mixtures thereof. Vaporized precursor may also be used. At least one of the gas sources144may contain gases used in the pre-treatment process of the present disclosure (e.g., NH3, N2, etc.). The gas sources144are connected by valves148-1,148-2, . . . , and148-N (collectively valves148) and mass flow controllers152-1,152-2, . . . , and152-N (collectively mass flow controllers152) to a manifold154. An output of the manifold154is fed to the processing chamber104. For example only, the output of the manifold154is fed to the showerhead124. In some examples, an optional ozone generator156may be provided between the mass flow controllers152and the manifold154. In some examples, the substrate processing system100may include a liquid precursor delivery system158. The liquid precursor delivery system158may be incorporated within the gas delivery system140as shown or may be external to the gas delivery system140. The liquid precursor delivery system158is configured to provide precursors that are liquid and/or solid at room temperature via a bubbler, direct liquid injection, vapor draw, etc.

A heater160may be connected to a heater coil (not shown) arranged in the pedestal112to heat the pedestal112. The heater160may be used to control a temperature of the pedestal112and the substrate120. A valve164and pump168may be used to evacuate reactants from the processing chamber104. A controller172may be used to control various components of the substrate processing system100. For example only, the controller172may be used to control flow of process, carrier and precursor gases, striking and extinguishing plasma, removal of reactants, monitoring of chamber parameters, etc.

An RF filter module (e.g., an RF filter box)176is arranged adjacent to the processing chamber104to filter RF noise from electrical signals communicated to and from components within the processing chamber104. For example, the RF filter module176is arranged below the processing chamber104on a bottom surface178of the processing chamber104adjacent to a portion (e.g., a stem)180of the pedestal112extending below the bottom surface178. Although shown directly adjacent to the pedestal112for simplicity, other structures may be arranged between the pedestal112and the RF filter module176. The RF filter module176encloses one or more tuning circuits, RF filter circuits, etc. (not shown inFIG. 1). The tuning circuits may be connected (i) between the first matching network130-1and a corresponding electrode, such as the electrode116and (ii) between the power source132and a corresponding electrode.

The tuning circuits control the RF voltages supplied to the electrode116and may include variable and/or fixed impedances that may be tuned for the substrate processing being performed. The RF voltages and corresponding current supplied to the electrode116may be controlled to change aspects of generated plasma. For example, in some capacitive coupled plasma (CCP) systems, RF voltage signals can be supplied to the lower electrode116to create and sustain plasma. Other electrical signals (e.g., power signals provided from a heater160) may pass through the RF filter module176. Example tuning and RF filter circuits that may be enclosed within the RF filter module176according to the principles of the present disclosure are described in more detail in U.S. patent application Ser. No. 16/052,877, filed on Aug. 2, 2018, the entire contents of which are hereby incorporated herein.

Referring now toFIGS. 2A and 2B, bottom plan views of an example substrate processing tool200of a substrate processing system are shown. The tool200may include one or more processing stations204. As shown, the substrate processing tool200includes four of the stations204but in other examples fewer or more of the stations204may be included. Each of the stations204may be configured to perform the same or different processes performed in others of the stations204.

Each of the stations204includes a corresponding pedestal208and a respective RF filter module212configured and arranged according to the principles of the present disclosure. As shown, a pedestal control module216is arranged adjacent to the pedestal208. For example, the pedestal control module216includes actuators, circuitry, etc. configured to control raising and lowering and rotation of the pedestal208. Each of the RF filter modules212is arranged to facilitate installation and servicing. For example, each of the RF filter modules212is in a same position relative to a respective one of the pedestals208and an outer perimeter220of the substrate processing tool200. A panel (e.g., a removable side or front panel)224of the RF filter module212faces outward toward the outer perimeter220to facilitate servicing.

Referring now toFIGS. 3A, 3B, 4A, and 4B, views of an example RF filter module (i.e., a rectangular RF filter box)300are shown. The RF filter module300includes exterior panels including a front panel (e.g., a removable front panel)304, a back panel308, side panels312and316, a top panel320, and a bottom panel324. InFIGS. 4A and 4B, the RF filter module300is shown with the front panel304and the top panel320removed.

While generally rectangular, the RF filter module300includes a notched or recessed corner328. The RF filter module300includes at least one adjustable capacitor332for adjusting parameters of the RF filter module300. For example, the adjustable capacitor332inFIGS. 4A and 4Breceives an RF input signal (e.g., via a right angle RF cable connector336) and magnitudes of RF voltages output by the RF filter module300vary in accordance with the adjusted capacitance of the capacitor332.

In some examples, the capacitor332includes first and second cylinders that have a variable overlap. The capacitance of the adjustable capacitor332may be adjusted using an encoder340and motor344(e.g., responsive to a signal from the controller172indicating a commanded position of the motor344). For example, the motor344varies the overlap of the first and second cylinders of the capacitor332to vary the capacitance. For example, the motor344corresponds to a stepper motor and the encoder340corresponds to an absolute encoder that maps the capacitance of the capacitor332to the commanded position of the motor344. While the capacitor332is enclosed within the RF filter module300, the encoder340and the motor344are located outside of the RF filter module300within the notched corner328. Accordingly, access to the motor344(e.g., for replacement, servicing, etc.) is facilitated.

The RF filter module300includes a plurality of fans, including fans348and352arranged on an upper portion of the front panel304and a fan356arranged on a lower portion of the back panel308. For example only, the fans348,352, and356correspond to 80 mm fans and are each mounted to the RF filter module300via a respective vibration pad358. The back panel308may also include output contact interfaces360and364for connectors (not shown) for providing output signals to the heater160and the electrode116, respectively (e.g., signals corresponding to heater power signals and RF output voltages). A contact switch368is arranged to provide signals (e.g., to the controller172) indicating whether the RF filter module300is installed and secured and the connecter336is connected to the RF filter module300as described below in more detail. For example, the contact switch368is arranged on an adapter bracket (not shown inFIGS. 3A, 3B, 4A, and 4B; described below in more detail) attached to the RF filter module300.

The side panels312and316include a plurality of latches372arranged to mount the RF milter module300to the substrate processing tool200. The bottom panel324includes input contact interfaces376and378for connectors (not shown) for receiving input signals for DC power (e.g., to provide DC power to internal circuitry of the RF filter module300) and heater power (e.g., to provide power to the heater160).

In some examples, the side panel312corresponds to a side of the RF filter module300facing outward toward the outer perimeter220of the substrate processing tool200to facilitate servicing as described above inFIGS. 2A and 2B. The side panel312includes an RF input connector380configured to receive the RF cable connector336. The RF input connector380receives the RF input signal from the RF cable connector336and provides the RF input signal to the adjustable capacitor332as described above.

A contact mechanism such as a flat spring (e.g., a leaf spring)382is arranged at an interface between the RF input connector380and the RF cable connector336. For example, the RF cable connector336connects to the RF input connector380through an opening384in the leaf spring382. A first end (e.g., corresponding to an end with a mounting bracket386) of the leaf spring382is connected to the side panel312while a second end (e.g., corresponding to a contact portion388) extends past a perimeter of the side panel312over the contact switch368.

Connecting the RF cable connector336to the RF input connector380(e.g., by tightening the connection using nut390) biases the leaf spring382toward the side panel312and the contact switch368. For example, the contact switch368may include a button392or other contact mechanism. Accordingly, when the RF cable connector336is connected to the RF input connector380, the contact portion388of the leaf spring382engages (e.g., contacts) the button392of the contact switch368. The contact switch368is configured to generate signals indicating whether the contact portion388is in contact with the contact switch368(i.e., in accordance with a position of the leaf spring382).

In this manner, the signals generated by the contact switch368indicate multiple statuses associated with the RF filter module300. For example, the signals indicate whether the RF filter module300is installed on the substrate processing tool200and whether the RF cable connector336is connected to the RF input connector380. In some examples, the side panel312may include a removable access panel394for providing access to internal circuitry of the RF filter module300. The leaf spring382may be mounted to the side panel312via the access panel394. For example, the mounting bracket386may be attached to the side panel312through the access panel394. Accordingly, the signals generated by the contact switch368based on the position of the leaf spring382may further indicate whether the access panel394is attached to the side panel312.

As shown inFIGS. 4A and 4B, the RF filter module300may define multiple compartments, such as compartments400,402, and404, and internal panels (e.g., sheet metal panels)406,408, and410. For example, the adjustable capacitor332is mounted on the panel406. The panel408separates the compartment400from the compartment402. The panel410separates the compartment402from the compartment404. The panels408and410prevent signal leakage between respective components within the compartments400,402, and404. For example, the panel408prevents RF noise from leaking from the compartment400into the compartment402, while the panel410prevents leakage between the compartments402and404.

The compartment400may enclose the adjustable capacitor332and the encoder340and circuitry such as a printed circuit board (PCB)412. The PCB412may correspond to a PCB comprising RF filter circuitry for filtering RF signals (e.g., as received via the RF cable connector336) provided to the pedestal112(e.g., via the output contact interface364). As shown, the adjustable capacitor332is mechanically coupled to the motor344via a shaft coupler416configured to rotate in accordance with the rotation of the motor344to adjust the adjustable capacitor332. An insulative spacer420is arranged around the shaft coupler416between the adjustable capacitor332and a surface of the panel406. Accordingly, the spacer420insulates the adjustable capacitor332from the panel406.

The compartment402may enclose circuitry such as a high frequency filter PCB (not shown) including circuitry for filtering high frequency signals (e.g., from signals provided via the contact interface378) and providing the filtered signals to the output contact interface360. The compartment404may enclose circuitry such as a low frequency filter PCB424including circuitry for filtering low frequency signals (e.g., from signals provided via the contact interface378) and providing the filtered signals to the output contact interface360.

FIGS. 5A, 5B, 5C, and 5Dshow views of another example of the RF filter module300according to the present disclosure. In this example, the fans348and352are in an offset arrangement. Further, rather than providing the opening384such that the RF cable connector336passes through the leaf spring384, the opening384is configured as a cutout around the RF cable connector336and the RF input connector380. In contrast to the example described inFIGS. 3A and 3B, the RF input connector380is integrated with the RF cable connector336. In other words, the RF cable connector336is not removably attached to the RF input connector380(e.g., using the nut390). The top panel320and/or other panels of the RF filter module300may include one or more zip tie anchors500and a fan bracket504.

As shown inFIGS. 5C and 5D, the back panel308of the RF filter module300is configured to connect to an adapter bracket508. For example, the adapter bracket508includes input contact interfaces512and516configured to connect to the output contact interfaces360and364, respectively. For example, the input contact interfaces512and516include pins520configured to be inserted into respective sockets524of the output contact interfaces360and364. Accordingly, when mounted on a processing chamber, the RF milter module300provides signals such as heater power and an RF output voltage to components of the processing chamber via the adapter bracket508. An alignment pin528extending from the adapter bracket508is arranged to be inserted into an alignment hole532in the back plate308of the RF filter module300. Conversely, an alignment pin536extending from the back plate308is arranged to be inserted into an alignment hole540in the adapter bracket508. The contact switch368is arranged on the adapter bracket508as shown inFIG. 5C.

As shown inFIG. 5C, the mounting bracket386of the leaf spring382is connected to the side panel312and a tuning circuit assembly544. The tuning circuit assembly544includes one or more components (e.g., an inductor548) arranged on a mounting plate552, which is attached to the side panel312. For example, the inductor548is arranged on a printed circuit assembly556arranged between standoffs560extending from the mounting plate552. The side panel312includes an opening564arranged to receive the components of the turning circuit assembly544extending from the mounting plate552.

FIG. 5Eshows a close-up view of a portion of a front panel304of the RF filter module300with a probe interface module568connected to the RF cable connector336. The probe interface module568includes a connector570for connecting an RF probe (e.g., a VI probe).FIG. 5Fis a bottom plan view of the RF filter module300ofFIGS. 5A, 5B, 5C, and 5D.