Patent ID: 12217939

In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

In a capacitive coupled plasma (CCP) system, RF voltage signals can be supplied to a showerhead and/or a substrate support (e.g., an electrostatic chuck or pedestal) in a processing chamber in order to create and sustain plasma provided for substrate processing (e.g., plasma provided during etching or deposition processes). As an example, the substrate support may include multiple electrodes for receiving RF voltages. The electrodes have respective geometries and thus may have different sizes and shapes and may be disposed in different locations within the substrate support.

The examples set forth herein include tuning circuits for controlling the RF voltages supplied to the electrodes of a substrate support. The tuning circuits 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 electrodes may be controlled to change aspects of generated plasma. During processing, a substrate is disposed on the substrate support and one or more layers (e.g., film layers) of the substrate may be, for example, etched or deposited. By tailoring the RF voltages supplied to the different electrodes, parameters of the one or more layers can be altered and/or tuned in a spatial manner across the wafer according to the location of the electrodes. As an example, parameters of the one or more layers may include uniformity values, stress values, a refractive index, an etch rate, a deposition rate, thickness values, and/or other intrinsical property values that are measured quantities.

RF power is disclosed as being provided from one or more RF power sources. In one embodiment, RF power is provided by feeding a common node RF power from a single RF power source. The RF power is then provided from the common node to different electrodes of a substrate support via respective paths. The paths include the tuning circuits and/or impedances, which alter the corresponding RF voltages, current levels, phases, and/or frequency content. The impedances may include series or shunt connected impedances. Other embodiments including multiple power sources, multiple nodes, and various paths are disclosed herein.

The RF voltages and current levels provided to the electrodes in a substrate support may also be altered by adjusting the size, shape, and pattern of the electrodes. For example, the RF voltages and amounts of current provided from annular-shaped and/or circular-shaped electrodes to plasma, the substrate processing performed using the annular-shaped and/or circular-shaped electrodes, and/or the resulting substrate characteristics can be altered and/or tuned by changing radii of the electrodes.

A substrate processing system may have multiple features, characteristics and/or parameters that provide degrees-of-freedom and may be set and/or adjusted to control resulting aspects of layers of a substrate during substrate processing. For example, RF power levels, chamber geometry, use of a focusing ring, showerhead hole patterns, showerhead shapes, electrode patterns, gas pressures, gas compositions, etc. may be set and/or controlled to provide a resultant substrate with a target layer make up and profile.

The disclosed examples provide another degree-of-freedom for tuning a profile of one or more layers of a substrate. The degree-of-freedom is provided by the setting and/or adjusting of the impedances (e.g., selecting, changing and/or controlling capacitances, inductances, reactances, resistances, layout, etc.) of the tuning circuits. The profile refers to the above-stated parameters of the one or more layers.

A radial profile of a substrate may be altered, for example, by altering metallic or dielectric annular elements near a circumferential edge of the substrate. This may include adjusting parameters, such as gas pressures, gas flow rates, gas composition, RF discharge power, frequencies of RF signals provided to electrodes of a substrate support, and/or other parameters. Altering these parameters at certain locations to provide a target layer feature (e.g., a certain layer thickness or shape at the circumferential edge) can alter other parameters and/or affect other features in the same location and/or in other locations. Thus, these parameters do not independently adjust certain features. As another example, a circumferential edge of a substrate may be altered by using a focusing ring located outside the circumferential edge of the substrate. The use of the focusing ring can however affect flow rates of gas at a center of the substrate, which can affect processing and thus a result at the center of the substrate. Other example layer features are a certain trench depth or width, distances between trenches, distances between conductive elements, layer compositions, etc.).

The more parameters and degrees-of-freedom in setting and controlling tuning of a profile of one or more layers of a substrate, the more likely certain features are able to be provided without negatively affecting other features. Also, as the number of parameters and degrees-of-freedom increase, the number, makeup and layout (or pattern) of features that can be formed increases. The examples disclosed herein increase substrate layer design flexibility and location specific design selectivity and allow a substrate processing system to provide a diverse set of features.

FIG.1shows a substrate processing system100incorporating an ESC101. The ESC101may be configured the same or similarly as any of the ESCs disclosed herein.

AlthoughFIG.1shows a capacitive coupled plasma (CCP) system, the embodiments disclosed herein are applicable to transformer coupled plasma (TCP) systems, electron cyclotron resonance (ECR) plasma systems, inductively coupled plasma (ICP) systems and/or other systems and plasma sources that include a substrate support. The embodiments are applicable to PVD processes, PECVD processes, chemically enhanced plasma vapor deposition (CEPVD) processes, ion implantation processes, plasma etching processes, and/or other etch, deposition, and cleaning processes.

The ESC101may include a top plate102and a baseplate103. Although the ESC101is shown as having two plates, the ESC may include a single plate. The plates102,103may be formed of ceramic and/or other materials. Although the ESCs ofFIGS.1-5and7-11are each shown as having certain features and not other features, each of the ESCs may be modified to include any of the features disclosed herein and inFIGS.1-5and7-11.

Although the ESC101is shown as being mounted to a bottom of a processing chamber and not being configured to be rotated, the ESC101and other ESCs disclosed herein may be mounted to a bottom or a top of a processing chamber and may be configured as a spin chuck to be rotated during processing of a substrate. If mounted to a top of a processing chamber, the ESC may have similar configurations to that disclosed herein, but flipped upside down and may include peripheral substrate holding, clamping, and/or clasping hardware.

The substrate processing system100includes a processing chamber104. The ESC101is enclosed within the processing chamber104. The processing chamber104also encloses other components, such as an upper electrode105, and contains RF plasma. During operation, a substrate107is arranged on and electrostatically clamped to the top plate102of the ESC101.

For example only, the upper electrode105may include a showerhead109that introduces and distributes gases. The showerhead109may include a stem portion111including one end connected to a top surface of the processing chamber104. The showerhead109is generally cylindrical and extends radially outward from an opposite end of the stem portion111at a location that is spaced from the top surface of the processing chamber104. A substrate-facing surface or the showerhead109includes holes through which process or purge gas flows. Alternately, the upper electrode105may include a conducting plate and the gases may be introduced in another manner. One or both of the plates102,103may perform as a lower electrode.

One or both of the plates102,103may include temperature control elements (TCEs). As an example,FIG.1shows the top plate102including TCEs110and being used as a heating plate. An intermediate layer114is arranged between the plates102,103. The intermediate layer114may bond the top plate102to the baseplate103. As an example, the intermediate layer may be formed of an adhesive material suitable for bonding the top plate102to the baseplate103. The baseplate103may include one or more gas channels115and/or one or more coolant channels116for flowing backside gas to a backside of the substrate107and coolant through the baseplate103.

An RF generating system120generates and outputs RF voltages to the upper electrode105and the lower electrode (e.g., one or more of the plates102,103). One of the upper electrode105and the ESC101may be DC grounded, AC grounded or at a floating potential. For example only, the RF generating system120may be controlled by a system controller121and include one or more RF generators122(e.g., a capacitive coupled plasma RF power generator, a bias power generator, and/or other RF power generator) that generate RF voltages, which are fed by one or more matching and distribution networks124to the upper electrode105and/or the ESC101. As an example, a first RF generator123, a second RF generator125, a first RF matching network127and a second RF matching network129are shown. The first RF generator123and the first RF matching network127may provide a RF voltage or may simply connect the showerhead109to a ground reference. The second RF generator125and the second RF matching network129may each or collectively be referred to as a power source and provide a RF/bias voltage to the ESC101. In one embodiment, the first RF generator123and the first RF matching network127provides power that ionizes gas and drives plasma. In another embodiment, the second RF generator125and the second RF matching network129provides power that ionizes gas and drives plasma. One of the RF generators123,125may be a high-power RF generator producing, for example 6-10 kilo-watts (kW) of power or more.

The second RF matching network129includes impedances128and supplies power to RF electrodes, such as RF electrodes131,133in the plates102,103. The RF electrodes may be located in one or both of the plates102,103. The RF electrodes may be located near an upper surface of the ESC101, for example, when being used as clamping electrodes and/or in other locations in the ESC101when being used for biasing purposes. The RF electrodes may receive power alternatively or in addition from other power sources. As an example, some of the RF electrodes may receive power from a power source135instead of or in addition to receiving power from the second RF matching network129. In one embodiment, the power source135does not include a matching network and/or no matching network is disposed between the power source135and the RF electrodes. Some of the RF electrodes may receive power from the second RF matching network129and/or the power source135to electrostatically clamp a substrate to the top plate102. The power source135may be controlled by the system controller121. Tuning circuits139may be connected (i) between the second RF matching network129and corresponding ones of the electrodes131,133,137, and (ii) between the power source135and corresponding ones of the electrodes131,133,137. In an embodiment, the tuning circuits139are disposed outside the processing chamber104separate from and downstream from the second RF matching network129. Examples of the tuning circuits139are shown inFIGS.2-11.

A gas delivery system130includes one or more gas sources132-1,132-2, . . . , and132-N (collectively gas sources132), where N is an integer greater than zero. The gas sources132supply one or more precursors and gas mixtures thereof. The gas sources132may also supply etch gas, carrier gas and/or purge gas. Vaporized precursor may also be used. The gas sources132are connected by valves134-1,134-2, . . . , and134-N (collectively valves134) and mass flow controllers136-1,136-2, . . . , and136-N (collectively mass flow controllers136) to a manifold140. An output of the manifold140is fed to the processing chamber104. For example only, the output of the manifold140is fed to the showerhead109.

The substrate processing system100further includes a cooling system141that includes a temperature controller142, which may be connected to the TCEs110. In one embodiment, the TCEs110are not included. Although shown separately from a system controller121, the temperature controller142may be implemented as part of the system controller121. One or more of the plates102,103may include multiple temperature controlled zones (e.g.,4zones, where each of the zones includes 4 temperature sensors).

The temperature controller142may control operation and thus temperatures of the TCEs110to control temperatures of the plates102,103and a substrate (e.g., the substrate107). The temperature controller142and/or the system controller121may control flow rate of backside gas (e.g., helium) to the gas channels115for cooling the substrate by controlling flow from one or more of the gas sources132to the gas channels115. The temperature controller142may also communicate with a coolant assembly146to control flow of a first coolant (pressures and flow rates of a cooling fluid) through the channels116. The first coolant assembly146may receive a cooling fluid from a reservoir (not shown). For example, the coolant assembly146may include a coolant pump and reservoir. The temperature controller142operates the coolant assembly146to flow the coolant through the channels116to cool the baseplate103. The temperature controller142may control the rate at which the coolant flows and a temperature of the coolant. The temperature controller142controls current supplied to the TCEs110and pressure and flow rates of gas and/or coolant supplied to channels115,116based on detected parameters from sensors143,144within the processing chamber104. The sensors143,144may include resistive temperature devices, thermocouples, digital temperature sensors, temperature probes, and/or other suitable temperature sensors. The sensors143,144and/or other sensors included in the substrate processing system100may be used to detect parameters, such as temperatures, gas pressures, voltages, current levels, etc. During an etch process, the substrate107may be heated up by a predetermined temperature (e.g., 120 degrees Celsius (° C.)) in presence of high-power plasma. Flow of gas and/or coolant through the channels115,116reduces temperatures of the baseplate103, which reduces temperatures of the substrate107(e.g., cooling from 120° C. to 80° C.).

A valve156and pump158may be used to evacuate reactants from the processing chamber104. The system controller121may control components of the substrate processing system100including controlling supplied RF power levels, pressures and flow rates of supplied gases, RF matching, etc. The system controller121controls states of the valve156and the pump158. A robot170may be used to deliver substrates onto, and remove substrates from, the ESC101. For example, the robot170may transfer substrates between the ESC101and a load lock172. The robot170may be controlled by the system controller121. The system controller121may control operation of the load lock172.

The valves, gas and/or coolant pumps, power sources, RF generators, etc. may be referred to as actuators. The TCEs, gas channels, coolant channels, etc. may be referred to as temperature adjusting elements.

The system controller121may control states of impedances of the tuning circuits139. Examples of the impedances are shown inFIGS.7-11. The impedances of the tuning circuits139may be adjusted based on feedback signals received from the sensors143,144,145and/or other sensors in the substrate support101, the processing chamber104, the second RF matching network129, and/or in one or more of the power sources125,135. The sensors145may detect voltages, current levels, power levels in the second RF matching network129. Although the sensors are shown in the baseplate103, one or more of the sensors may be located in the top plate102. The sensors104may be located anywhere in the substrate support101. The sensors143may be located anywhere in the processing chamber104.

The system controller121may also control states of the impedances128. The states of the impedances128may be set, such that one or more impedances of one or more outputs of the second RF matching network129matches impedances seen at inputs of the tuning circuits139. The impedances seen at the inputs of the tuning circuits139are based on impedances of the substrate support101and the tuning circuits139. When adjusting the impedances of the tuning circuits139, the system controller121may also adjust impedances of the second RF matching network129accordingly.

Although in the following describedFIGS.2-11a certain number of tuning circuits, impedances, clamping electrodes, RF electrodes, and/or other elements are shown, any number of each may be included. Also, although the tuning circuits, impedances, clamping electrodes and RF electrodes are shown in certain arrangements and having certain sizes, shapes, and patterns, the stated elements may be in different arrangements and have different sizes, shapes, and patterns.

FIG.2shows a capacitive coupling circuit200including a clamping tuning circuit202, a RF tuning circuit204, a clamping electrode206and a RF electrode208. Cross-sectional views of a showerhead (or upper electrode)210and an ESC212are shown. The showerhead210may be connected to a reference potential or ground214. In an embodiment, the showerhead210is RF powered by the first RF matching network127ofFIG.1. Plasma216is provided between the showerhead210and the ESC212. A substrate218is disposed on the ESC212.

The clamping tuning circuit202may be used to control clamping voltages, current levels, phases, power levels and/or frequencies provided to the clamping electrode206. The RF tuning circuit204may be used to control bias voltages, current levels, power levels and/or frequencies provided to the RF electrode208. The tuning circuits202,204may receive power Pinner, Pouterfrom, for example, the second RF matching network129(or first power source) and/or the power source135(or second power source) ofFIG.1and be used to adjust voltage drops across plasma. This may include adjusting voltage differences between respective pairs of points above and across a surface of the substrate support101ofFIG.1. Examples of the tuning circuits202,204are shown inFIG.6. The tuning circuits202,204may include one or more of the impedances, as shown inFIG.6. The tuning circuits202,204may not include a parallel impedance path or may include a transmission line instead of a serial impedance path. Example parallel and serial impedance paths are shown inFIG.6. Examples of the impedances that may be included in the tuning circuits202,204are shown inFIGS.7-11. The impedances may be serial or parallel connected, may be shunt impedances, and/or may include capacitors, inductors, resistors, reactances, transmission lines, shorted or open circuit, filtering elements (or filters) and/or other impedances. As an example, the clamping electrode206may be circular-shaped and the RF electrode208may be annular-shaped.

FIG.3shows a capacitive coupling circuit300including a first clamping tuning circuit302, a second clamping tuning circuit303, an outer RF tuning circuit304, a first clamping electrode306, a second clamping electrode307and a RF electrode308. Cross-sectional views of a showerhead (or upper electrode)310and an ESC312are shown. The showerhead310may be connected to a reference potential or ground314. In an embodiment, the showerhead310is RF powered by the first RF matching network127ofFIG.1. Plasma316is provided between the showerhead310and the ESC312. A substrate318is disposed on the ESC312.

The clamping tuning circuits302,303may be used to control clamping voltages, current levels, power levels and/or frequencies provided to the clamping electrodes306,307. The RF tuning circuit304may be used to control bias voltages, current levels, power levels and/or frequencies provided to the RF electrode308. The tuning circuits302,303, and304may receive power Pclamp1, Pclamp2, and Pouterfrom, for example, the second RF matching network129(or first power source) ofFIG.1, the power source135(or second power source) ofFIG.1, and/or from one or more other power sources. The tuning circuits302,303,304may be used to adjust voltage drops across plasma. In one embodiment, Pclamp1is equal to Pclamp2. Examples of the tuning circuits302,303,304are shown inFIG.6. The tuning circuits302,303,304may include one or more of the impedances, as shown inFIG.6. The tuning circuits302,303,304may not include a parallel impedance path or may include a transmission line instead of a serial impedance path. Examples of the impedances that may be included in the tuning circuits302,303,304are shown inFIGS.7-11. The impedances may be serial or parallel connected, may be shunt impedances, and/or may include capacitors, inductors, resistors, reactances, transmission lines, shorted or open circuit, filtering elements and/or other impedances. As an example, the clamping electrodes306,307may be circular-shaped and the RF electrode308may be annular-shaped.

FIG.4shows a capacitive coupling circuit400that includes a clamping tuning circuit402, an inner RF tuning circuit404, an outer RF tuning circuit405, a clamping electrode406, an inner bias electrode408and an outer bias electrode409. Cross-sectional views of a showerhead (or upper electrode)410and an ESC412are shown. The showerhead410may be connected to a reference potential or ground414. In an embodiment, the showerhead410is RF powered by the first RF matching network127ofFIG.1. Plasma416is provided between the showerhead410and the ESC412. A substrate418is disposed on the ESC412.

The clamping tuning circuit402may be used to control clamping voltages, current levels, phases, power levels and/or frequencies provided to the clamping electrode406. The RF tuning circuits404,405may be used to control bias voltages, current levels, power levels and/or frequencies provided to the bias electrodes408,409. The tuning circuits402,404,405may receive power Pclamp, Pinner, Pouterfrom, for example, the second RF matching network129(or first power source) ofFIG.1, the power source135(or second power source) ofFIG.1, and/or from one or more other power sources. The tuning circuits402,404,405may be used to adjust voltage drops across plasma. Examples of the tuning circuits402,404,405are shown inFIG.6. The tuning circuits402,404,405may include one or more of the impedances, as shown inFIG.6. The tuning circuits402,404,405may not include a parallel impedance path or may include a transmission line instead of a serial impedance path. Examples of the impedances that may be included in the tuning circuits402,404,405are shown inFIGS.7-11. The impedances may be serial or parallel connected, may be shunt impedances, and/or may include capacitors, inductors, resistors, reactances, transmission lines, shorted or open circuit, filtering elements and/or other impedances. As an example, the clamping electrode406and the inner bias electrode408may be circular-shaped and the outer bias electrode409may be annular-shaped.

FIG.5shows a capacitive coupling circuit500including a clamping tuning circuit502, a first inner RF tuning circuit504, a second inner tuning circuit505, an outer RF tuning circuit506, a clamping electrode507, a first inner bias electrode508, a second inner bias electrode509, and an outer bias electrode510. Cross-sectional views of a showerhead (or upper electrode)511and an ESC512are shown. The showerhead511may be connected to a reference potential or ground514. In an embodiment, the showerhead511is RF powered by the first RF matching network127ofFIG.1. Plasma516is provided between the showerhead511and the ESC512. A substrate518is disposed on the ESC512.

The clamping tuning circuit502may be used to control clamping voltages, current levels, power levels and/or frequencies provided to the clamping electrode507. The RF tuning circuits504,505,506may be used to control bias voltages, current levels, phases, power levels and/or frequencies provided to the bias electrodes508,509,510. The tuning circuits502,504,505,506may receive power Pclamp, Pinner1, Pinner2, Pouterfrom, for example, the second RF matching network129(or first power source) ofFIG.1, the power source135(or second power source) ofFIG.1, and/or from one or more other power sources. The tuning circuits502,504,505,506may be used to adjust voltage drops across plasma. Examples of the tuning circuits502,504,505,506are shown inFIG.6. The tuning circuits502,504,505,506may include one or more of the impedances, as shown inFIG.6. The tuning circuits502,504,505,506may not include a parallel impedance path or may include a transmission line instead of a serial impedance path. Examples of the impedances that may be included in the tuning circuits502,504,505,506are shown inFIGS.7-11. The impedances may be serial or parallel connected, may be shunt reactances, and/or may include capacitors, inductors, resistors, reactances, transmission lines, shorted or open circuit, filtering elements and/or other impedances. As an example, the clamping electrode507and the bias electrodes508,509may be circular-shaped and the outer bias electrode510may be annular-shaped.

FIG.6shows a tuning circuit600for an electrode (or load)602, such as a clamping electrode or a bias electrode. The tuning circuit600may replace any of the tuning circuits202,204,302,304,305,402,404,405,502,504,505, and506ofFIGS.2-5. Examples of the tuning circuit600are shown inFIGS.9-10. The tuning circuit600may receive RF power from a RF power source604, such as one of the power sources129,135ofFIG.1. The tuning circuit600may include a serial impedance path605with a series impedance set606and a parallel impedance path607with a parallel impedance set608. The series impedance set606includes one or more impedances609connected in series between the RF power source604and the load602. The series impedance set606and the one or more impedances609are connected between the load602and a source terminal610. The source terminal610is connected to the RF power source604. The parallel impedance set608is connected between (i) the source terminal610that is connected between the RF power source604and the series impedance set606, and (ii) a reference terminal or ground612. The parallel impedance set608may include one or more impedances613connected in parallel between the source terminal610and the reference terminal612.

One or more of the impedances609,613may be fixed impedances. In addition or alternatively, one or more of the impedances609,613may be variable impedances, which may be adjusted by the system controller121ofFIG.1based on, for example: a current processing recipe; current operating parameters; parameters measured and/or determined based on outputs of one or more sensors (e.g., the sensors143ofFIG.1); and/or processing system, ESC and substrate features and/or characteristics.

Although in the followingFIGS.7-11, certain impedances are shown, other impedances may be included. The impedances may include “stray” inductance from wires and/or other conductive circuit elements.

FIG.7shows a tuning circuit700may be connected to a single RF power source702. The tuning circuit700includes serially connected inductors L1-L3and capacitors C1-C3for two clamping electrodes706,708and a bias electrode ring710. The RF power source702may operate similarly to the power sources129,135ofFIG.1and may be connected to a reference terminal or ground711. In one embodiment (referred to as a grounded pedestal configuration), the RF power source702is not included and the capacitors C1-C3are connected to the ground711.

InFIG.7, cross-sectional views of the electrodes706,708,710are shown. The electrodes706,708,710may be concentrically disposed. L1and C1are connected in series between (i) the RF power source702and a common terminal712, and (ii) the first inner clamping electrode706. L2and C2are connected in series between (i) the RF power source702and a common (or source) terminal712, and (ii) and a central terminal714, which is connected to two points on the bias electrode ring710. L3and C3are connected in series between (i) the RF power source702and a common terminal712, and (ii) and the second inner clamping electrode708.

The inductors L1-L3and capacitors C1-C3may have fixed values or may be variable devices that are controlled by the system controller121ofFIG.1, as described above. Although inductors L1-L3and capacitors C1-C3are shown, other impedances may be incorporated in the tuning circuit700.

FIG.7provides an example of when power is provided to a common node (or terminal) and split to provide power to multiple electrodes. The impedance of each path to each electrode may be altered by the impedances (or serially connected inductances and capacitances) in the corresponding path.

FIG.8shows a tuning circuit800may be connected to a single RF power source802. The tuning circuit800includes shunt inductors L1-L3and shunt capacitors C1-C3for two clamping electrodes804,806and a bias electrode ring808. The RF power source802may operate similarly to the power sources129,135ofFIG.1and may be connected to a reference terminal or ground811. The RF power source802is connected to a common (or source) terminal812, which is connected to the clamping electrodes802,806and to a central terminal814.

In one embodiment (referred to as a grounded pedestal configuration), the RF power source802is not included and the terminal812is connected to the ground811. When the terminal812is connected to the ground811, one or more serially connected impedances may be connected (i) between the node820and the ground811, (ii) between the node822and the ground811, and/or between the node824and the ground811. The stated one or more serially connected impedances may be similar to the impedances L1-L3and C1-C3or may include other impedances. This may occur, for example, when a corresponding showerhead is provided with RF power.

Cross-sectional views of the electrodes802,806,808are shown. The electrodes802,806,808may be concentrically disposed. L1and C1are connected in parallel between a first terminal820and the ground811. The first terminal820is connected between the common terminal812and the first clamping electrode802. L2and C2are connected in parallel between a second terminal822and the ground811. The second terminal822is connected between the common terminal812and the first clamping electrode802. L3and C3are connected in parallel between a third terminal824and the ground811. The third terminal824is connected between the common terminal812and the second clamping electrode806.

The inductors L1-L3and capacitors C1-C3may have arbitrary and/or predetermined fixed values or may be variable devices that are controlled by the system controller121ofFIG.1, as described above. Although inductors L1-L3and capacitors C1-C3are shown, other impedances may be incorporated in the tuning circuit800.

FIG.8provides another example of when power is provided to a common node and split to provide power to multiple electrodes. The impedance of each path to each electrode may be altered by the shunt impedances (or shunt inductances and capacitances) connected to the corresponding path.

FIG.9shows a tuning circuit900connected to dual RF power sources902,904. The tuning circuit900includes serially connected inductors L1-L3and capacitors C1-C3and shunt inductors L4-L6and capacitors C4-C6for two clamping electrodes906,908and a bias electrode ring910. The RF power sources902,904may operate similarly to the power sources129,135ofFIG.1and may be connected to a reference terminal or ground911. The RF power sources902,904are connected to a common (or source) terminal912and may provide power at a same frequency or at different frequencies.

In one embodiment (referred to as a grounded pedestal configuration), the RF power sources902,904are not included and the terminal912is connected to the ground911. When the terminal912is connected to the ground911, one or more serially connected impedances may be connected (i) between the node920and the ground911, (ii) between the node922and the ground911, and/or between the node924and the ground911. The stated one or more serially connected impedances may be similar to the impedances L1-L3and C1-C3or may include other impedances. This may occur, for example, when a corresponding showerhead is provided with RF power.

The inductor L1and capacitor C1are connected in series between the common terminal912and the first clamping electrode906. The inductor L2and the capacitor C2are connected in series between a central terminal914and the common terminal912. The central terminal is connected to two points on the bias electrode ring910.

Cross-sectional views of the electrodes906,908,910are shown. The electrodes906,908,910may be concentrically disposed. L4and C4are connected in parallel between a first terminal920and the ground911. The first terminal920is connected between capacitor C1and the common terminal912. L5and C5are connected in parallel between a second terminal922and the ground911. The second terminal922is connected between the capacitor C2and the common terminal912. L6and C6are connected in parallel between a third terminal924and the ground911. The third terminal924is connected between the capacitor C3and the common terminal912.

The inductors L1-L6and capacitors C1-C6may have arbitrary and/or predetermined fixed values or may be variable devices that are controlled by the system controller121ofFIG.1, as described above. Although inductors L1-L6and capacitors C1-C6are shown, other impedances may be incorporated in the tuning circuit900. L4-L6and C4-C6may be arbitrary networks, which may not include inductors and/or capacitors.

FIG.10shows two tuning circuits1000,1002may be connected to respective RF power sources1004,1006. The first tuning circuit1000includes serially connected inductors L1, L3and capacitors C1, C3and shunt inductors L4, L6and capacitors C4, C6for two clamping electrodes1010,1012. The second tuning circuit1002includes serially connected inductor L2and capacitor C2and shunt inductor L5and capacitor C5for a bias electrode ring1014. The RF power sources1004,1006may operate similarly to the power sources129,135ofFIG.1and may be connected to a reference terminal or ground1016. The RF power source1004is connected to a common (or source) terminal1018, which is connected to C1, C3, C4, C6, L4, L6. The RF power source1006is connected to a central terminal1020via C2and L2. The RF power sources1004,1006may provide power at a same frequency or at different frequencies.

The inductor L1and capacitor C1are connected in series between the common terminal1018and the first clamping electrode1010. The inductor L2and the capacitor C2are connected in series between a central terminal1020and RF power source1006. The central terminal1020is connected to two points on the bias electrode ring1014.

Cross-sectional views of the electrodes1010,1012,1014are shown. The electrodes1010,1012,1014may be concentrically disposed. L4and C4are connected in parallel between a first terminal1030and the ground1016. The first terminal1030is connected between capacitor C1and the common terminal1018. L5and C5are connected in parallel between a second terminal1032and the ground1016. The second terminal1032is connected between the capacitor C2and the common terminal1018. L6and C6are connected in parallel between a third terminal1034and the ground1016. The third terminal1034is connected between the capacitor C3and the common terminal1018.

The inductors L1-L6and capacitors C1-C6may have arbitrary and/or predetermined fixed values or may be variable devices that are controlled by the system controller121ofFIG.1, as described above. Although inductors L1-L6and capacitors C1-C6are shown, other impedances may be incorporated in the tuning circuit1000. L4-L6and C4-C6may be arbitrary networks, which may not include inductors and/or capacitors.

In one embodiment, the RF power source1004is not included and the terminal1018is connected to the ground1016. In another embodiment, the RF power source1006is not included and the terminal1032is connected to the ground1016. In yet another embodiment, neither of the RF power sources1004,1006are included and both of the terminals1018and1032are connected to the ground1016. When the terminal1018and/or the terminal1032is connected to the ground1016, one or more serially connected impedances may be connected (i) between the node1030and the ground1016, (ii) between the node1034and the ground1016, and/or between the node1032and the ground1016. The stated one or more serially connected impedances may be similar to the impedances L1-L3and C1-C3or may include other impedances. This may occur, for example, when a corresponding showerhead is provided with RF power.

FIG.11shows a tuning circuit1100including parallel connected capacitors C1, C2and inductors L1, L2for two clamping electrodes1102,1104and a bias electrode ring1106. The electrodes1102,1104,1106may be concentrically disposed. The capacitors C1and C2are connected in series (i) between the clamping electrodes1102,1104, and (ii) between power source terminals1110,1112. The inductors L1, L2are connected in parallel respectively with the capacitors C1, C2and in series (i) between the clamping electrodes1102,1104, and (ii) between power source terminals1110,1112. Center terminals1114,1116are connected respectively between the capacitors C1, C2and between the inductors L1, L2. The center terminals1114,1116are connected to both (i) two points on the bias electrode ring1106, and (ii) a third (or center) power source terminal1118. The power source terminals1110,1112are connected respectively to the clamping electrodes1102,1104. The power source terminals1110,1112,1118may be connected to respective power sources. In one embodiment, one or more of the power source terminals1110,1112,1118are not connected to a RF power source, but rather are connected to a reference terminal or ground.

The inductors L1-L2and capacitors C1-C2may have arbitrary and/or predetermined fixed values or may be variable devices that are controlled by the system controller121ofFIG.1, as described above. Although inductors L1-L2and capacitors C1-C2are shown, other impedances may be incorporated in the tuning circuit1100. The inductors L1-L2and the capacitors C1-C2are coupling elements connected between electrodes to provide power at multiple frequencies to each electrode.

The tuning circuit1100may be used in combination with any of the circuits shown inFIGS.3,5and7-10. For example, the capacitors C1, C2and the inductors L1, L2may be similarly connected to: the electrodes306,307and electrode ring308ofFIG.3; the electrodes508,509and electrode ring510ofFIG.5; the electrodes706,708and electrode ring710ofFIG.7; the electrodes802,806and electrode ring808ofFIG.8; the electrodes906,908and electrode ring910ofFIG.9; and the electrodes1010,1012and electrode ring1014ofFIG.10.

In the above-provided examples ofFIGS.2-11, if power is provided at multiple frequencies, the paths to a given electrode may include frequency dependent filtering elements to provide power at a particular frequency to that electrode. The above-described impedances may include the frequency dependent filtering elements. In addition, the power provided to different electrodes may be provided by separate (or different) power sources that operate at a same frequency or at different frequencies, such that the power provided by the power sources is at a same frequency or at different frequencies.FIGS.9-10show examples including multiple power sources. As an alternative, one or more of the power sources may not be included and the corresponding terminals (e.g., terminals912,1018,1032) may be connected to a reference terminal or a ground.

FIG.12shows an example method of operating a substrate processing system including setting and adjusting impedance values for tuning circuits of electrodes of an electrostatic chuck. Although the following operations are primarily described with respect to the implementations ofFIGS.1-11, the operations may be easily modified to apply to other implementations of the present disclosure. The operations may be iteratively performed. The operations may be performed by, for example, the system controller121ofFIG.1.

The method may begin at1200. At1202, a process to be performed is selected. Example processes are a cleaning process, an etching process, a deposition process, an annealing process, etc. At1204, a recipe including system operating parameters are determined for the selected process being performed. Example system operating parameters are: gas pressures and flow rates; processing chamber, ESC and substrate temperatures; RF bias voltages; clamping voltages; electrode voltages, current levels, power levels, and/or frequencies; etc.

At1206, features and/or characteristics of the processing chamber, ESC and substrate are determined. Example features and characteristics are processing chamber geometry values, makeup of the ESC, heating and cooling characteristics (e.g., heating and cooling rates) of the ESC, size of the ESC, makeup of the substrate, materials of the ESC and/or substrate, etc.

At1208, system operating parameters may be set by the system controller121. This may include controlling operation of the above-stated actuators. At1210, impedance values of tuning circuits are set based on the selected process, recipe, and system operating parameters. The impedance values may also or alternatively be set based on features and/or characteristics of the processing chamber, ESC and/or substrate. As an example, look-up tables may be stored in memory of the system controller121and/or accessed by the system controller121relating the impedance values to other parameters, features and/or characteristics stated herein. The system controller121may also set the impedances128of the second RF matching network129as described above.

At1212, the substrate may be arranged on the ESC. This may include providing clamping voltages to clamp the substrate to the ESC. At1214, processing operations are performed. Example processing operations are cleaning operations, flowing gases, flowing and striking plasma, etching operations, deposition operations, annealing operations, post annealing operations, purging the process chamber, etc.

Operations1216,1218,1220,1222may be performed while performing operation1212. At1216, sensor output signals including sensor output data of the substrate processing system are monitored. This may include receiving signals from the sensors143,144,145ofFIG.1. At1218, parameters may be determined based on the sensor output signals from the sensors143,144,145and/or other sensors, data and/or corresponding measured values, such as temperatures, gas pressures, voltages, current levels, power levels, etc.

At1220, the system controller121may determine whether to adjust impedance values of the tuning circuits based on the measured values and/or determined parameters. This determination may be based on the selected process, recipe, system operating parameters, and/or features and/or characteristics of processing chamber, ESC and/or substrate. The characteristics may dynamically change. In an embodiment, the impedance values are adjusted to follow predetermined trajectories based on the changes in the characteristics. The predetermined trajectories may be, for example, predetermined curves stored in memory. Tables may be stored in memory relating the impedance values to the other values and parameters. If one or more impedance values are to be changed, operation1222is performed, otherwise operation1216may be performed. In one embodiment, power supplied to one or more electrodes is modulated by changing the values of the corresponding impedances. This can be done to change stress, thicknesses, uniformity, a refractive index, an etch rate, a deposition rate, and/or other intrinsic values and/or profile parameters of the substrate.

At1222, the system controller121adjusts the one or more impedance values of the tuning circuits by, for example, changing inductance, capacitance, impedance, and/or resistance of the one or more impedances. The adjustment (or amount of adjustment) may be based on the measured and/or determined parameters, selected process, recipe, system operating parameters, and/or features and/or characteristics of processing chamber, ESC and/or substrate. The system controller121may also adjust the impedances128of the second RF matching network129as described above. Subsequent to operation1222, operation1216may be performed.

At1224, the system controller121determines whether to modify the current process or perform another process. Operation1202may be performed if the current process is to be modified or another process is to be performed. The method may end at1226if the current process is not modified and no further process is to be performed.

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

FIG.13shows an example of a substrate support1300including an outer ring electrode1302and two inner electrodes1304,1306. The electrodes1302,1304,1306are provided as an example of two inner electrodes and an outer ring electrode, as shown inFIGS.3,5, and7-11. The inner electrodes1304,1306may be D′-shaped electrodes and are disposed radially inward of the outer ring electrode1302. Gaps1308and1310exist between the inner electrodes1304,1306and the outer ring electrode1302. The outer ring electrode1302may include an outer ring1311and a linearly-shaped center member1312that extends between the inner electrodes1304,1306. Gaps1314and1316may exist between the inner electrodes1304,1306and the center member1312. The center member1312extends between the inner electrodes1304,1306and through a middle area1320of the outer ring1311to equally bifurcate the middle area1320. In an embodiment, power is provided to the outer ring electrode1302at a center of the center member1312. Power may be provided to portions of the inner electrodes1304,1306near a middle of the center member1312.

The above-described examples provide a RF tuning systems including tuning circuits having impedances for setting and adjusting parameters of electrodes in electrostatic chucks and/or other pedestals (or substrate supports). The pedestals may not be electrostatic chucks. This provides spatial tuning of power delivered to plasma in a processing chamber (e.g., a PECVD reactor). The examples provide new control parameters for film deposition and uniformity. As an example including an outer annular electrode and an inner circular electrode, relative intensity of plasma around the outer perimeter of the substrate may be altered by modulating power supplied to the electrodes. This may be accomplished by modulating (or adjusting) corresponding impedances, as described above. Unlike altering gas parameters or overall power, the modulating of the power provided to electrodes does not necessarily alter a global parameter affecting an entire substrate and allows a selected area of a film of a substrate to be altered (e.g., a circumferential edge of the film of the substrate). This is unlike traditional techniques that include use of metal or dielectric rings to alter an outer portion of plasma, which can result in gas flow variations and as a result have a global affect altering more of a film of a substrate film than a circumferential edge of the film.

The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various 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 first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

In some implementations, a controller is part of a system, which may be part of the above-described examples. Such systems can include semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller, depending on the processing requirements and/or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing 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 rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and/or load locks connected to or interfaced with a specific system.

Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and/or 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), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers 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.

The controller, in some implementations, may be a part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from multiple fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which 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, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which 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 that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by including one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel 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 systems that may be associated or used in the fabrication and/or manufacturing of semiconductor wafers.

As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and/or load ports in a semiconductor manufacturing factory.