TWI794240B - Processing tool for plasma process and plasma reactor - Google Patents

Abstract

A processing tool for a plasma process includes a chamber body that has an interior space that provides a plasma chamber and that has a ceiling and an opening on a side opposite the ceiling, a workpiece support to hold a workpiece such that at least a portion of a front surface of the workpiece faces the opening, an actuator to generate relative motion between the chamber body and the workpiece support such that the opening moves laterally across the workpiece, a gas distributor to deliver a processing gas to the plasma chamber, an electrode assembly comprising a plurality of coplanar filaments extending laterally through the plasma chamber between the workpiece support and the ceiling, each of the plurality of filaments including a conductor, and a first RF power source to supply a first RF power to the conductors of the electrode assembly to form a plasma.

Description

Processing tool and plasma reactor for plasma treatment

The present disclosure relates to a processing tool that includes a plasma chamber, such as a plasma chamber for depositing a film on a workpiece, such as a semiconductor wafer, etching a workpiece, or treating a workpiece.

The plasma is typically generated using a capacitively coupled plasma (CCP) source or an inductively coupled plasma (ICP) source. A basic CCP source consists of two metal electrodes, similar to a parallel plate capacitor, separated by a small distance in a gaseous environment. One of the two metal electrodes is driven by a fixed frequency radio frequency (RF) power supply, while the other electrode is connected to RF ground, creating an RF electric field between the two electrodes. The resulting electric field ionizes the gas atoms, releasing electrons. Electrons in the gas are accelerated by the RF electric field and ionize the gas directly or indirectly through collisions to generate plasma.

Basic ICP sources usually contain helical or coiled conductors. When RF current flows through a conductor, an RF magnetic field is formed around the conductor. The RF magnetic field is accompanied by the RF electric field, which ionizes the gas atoms and creates a plasma.

Plasmas of various processing gases are widely used in the manufacture of integrated circuits. For example, plasma can be used for thin film deposition, etching and surface treatment.

Atomic layer deposition (ALD) is a thin film deposition technique based on the sequential use of gas-phase chemical processes. Some ALD processes use plasma as chemical The chemical reaction provides the necessary activation energy. Plasma-enhanced ALD processes can be performed at lower temperatures than non-plasma-enhanced (eg, "thermal") ALD processes.

In one aspect, a processing tool for plasma processing includes a chamber body having an interior space, a workpiece support, an actuator, a gas distributor, an electrode assembly, and a first RF power supply. The space provides a plasma chamber, the chamber body has a top plate and an opening on a side opposite the top plate, the workpiece support holds the workpiece such that at least a portion of the front surface of the workpiece faces the opening, the actuator is in the Relative motion is generated between the chamber body and the workpiece support such that the opening moves laterally across the workpiece, the gas distributor delivers process gas to the plasma chamber, the electrode assembly includes a plurality of coplanar wires (coplanar filaments), the plurality of coplanar filaments extending laterally through the plasma chamber between the workpiece support and the top plate, each filament in the plurality of filaments comprising a conductor, the first RF power supply to the The conductors of the electrode assembly provide first RF power to form a plasma.

Implementations can include one or more of the following features.

The workpiece support is rotatable about a rotational axis, and the actuator is rotatable to rotate the workpiece support such that rotation of the support carries the workpiece across the opening.

A plurality of coplanar filaments may extend across the wedge-shaped region. The workpiece may fit completely within the wedge-shaped region such that in operation the entire front surface of the workpiece is exposed to the plasma. The workpiece may be larger than the wedge-shaped region such that in operation the wedge-shaped portion of the front surface of the workpiece is exposed to the plasma. The opening may be wedge-shaped.

The plurality of coplanar filaments may be linear filaments, and different filaments may have different lengths to define wedge-shaped regions. A plurality of coplanar filaments may extend in parallel. The plurality of coplanar filaments may be evenly spaced. Different filaments can be oriented at different angles. The plurality of coplanar filaments may be oriented such that a plasma density generated in the wedge-shaped region is lower at an apex of the wedge-shaped region than at a base of the wedge-shaped region. The plurality of coplanar filaments may be oriented to have a longitudinal axis at a non-zero angle relative to a direction of motion of the portion of the substrate below the opening. This non-zero angle may be greater than 10°.

The spacing between the coplanar filaments may be sufficient to avoid a pinch of the plasma region between regions above and below the electrode assembly within the chamber. The bottom of the chamber may be open. The tool may include a top electrode on the chamber ceiling.

The ends of the conductors of the plurality of coplanar filaments may be connected to the first RF power source by a loop-back RF feed structure. Opposite ends of the conductors of the plurality of coplanar filaments may be connected to a common bus. The bus can be connected to the first RF power source at two opposing locations.

A first multiconductor of the plurality of coplanar filaments may be connected to a first RF power source, and a second multiconductor of the plurality of coplanar filaments may be floating or grounded. First ends of the conductors of the plurality of coplanar filaments may be coupled to a first RF power source through a common bus. The conductors of the first set and the conductors of the second set may be arranged to alternate in a direction perpendicular to the longitudinal axis of the filament.

In another aspect, a plasma reactor includes a chamber body having an interior space that provides a plasma, a gas distributor, a workpiece support, an electrode assembly, a first RF power supply, and a dielectric floor chamber, the gas distributor delivers process gas to the plasma chamber, the workpiece support holds a workpiece, the electrode assembly includes a plurality of conductors in a parallel coplanar array with the workpiece support spaced apart and extending laterally across the workpiece support, the first RF power supply provides first RF power to the electrode assembly, the dielectric base is between the electrode assembly and the workpiece support, the dielectric base is between An RF window is provided between the electrode assembly and the plasma chamber.

Implementations can include one or more of the following features.

A plurality of conductors can be positioned between the dielectric top plate and the dielectric window. The dielectric top plate can be a ceramic body, and the dielectric bottom plate can be quartz or silicon nitride.

The lower surface of the base plate can have a plurality of parallel slots, and the plurality of parallel coplanar conductors can be positioned in the plurality of parallel slots. A plurality of wires may be positioned in a plurality of slots. Each filament may include a conductor and a non-metallic sheath surrounding the conductor. The shell may form a conduit, and the conductors may be suspended in and extend through the conduit. The conductor may comprise a hollow conduit.

A plurality of conductors may be coated on the dielectric top plate. A plurality of conductors may be embedded in the dielectric top plate.

The plurality of conductors may be evenly spaced. The spacing between the workpiece support and the plurality of conductors may be 2 mm to 50 cm.

The plurality of conductors may include a first multiplicity of conductors and a second multiplicity of conductors arranged in an alternating pattern with the first multiplicity of conductors. The RF power supply can be configured to apply a first RF input signal to the first multiple conductor, and apply a second RF input signal to the second multiple conductor. The RF power supply can be configured to generate the first RF signal and the second RF signal at the same frequency. The RF power supply may be configured to generate the first RF signal and the second RF signal such that the phase difference between the first RF signal and the second RF signal is 180°. The RF power supply can be configured to provide an adjustable phase difference between the first RF signal and the second RF signal.

The plurality of conductors may have a plurality of first ends on a first side of the plasma chamber and a plurality of second ends on an opposite second side of the plasma chamber. The RF power supply can be configured to apply the first RF input signal to the first end of the first multiconductor, and apply the second RF input signal to the second end of the second multiconductor. The second end of the first multiconductor may be floating, and the first end of the second multiconductor may be floating. A first end of the first multiconductor can be connected to the first common bus, and a second end of the second multiconductor can be connected to the second common bus. The first multifilament can be grounded, and the first end of the second multifilament can be grounded.

A first end of the first multiconductor may be connected to a first common bus located outside the plasma chamber on a first side of the chamber, and a second end of a second multiconductor may be connected to a second end of the plasma chamber located on a first side of the chamber. A second common bus outside the plasma chamber on both sides. The second end of the first multiconductor can be connected to a third common bus located outside the plasma chamber on the second side of the chamber, and the first end of the second multiconductor can be connected to a third common bus located on the first side of the chamber. A fourth common bus on the outside of the plasma chamber.

In another aspect, a plasma reactor includes a chamber body, a gas distributor, a pump, a workpiece support, an electrode assembly in a chamber, a first bus and a second bus, an RF power supply, and at least one RF switch. The chamber body has an interior space providing a plasma chamber, the gas distributor delivers process gas to the plasma chamber, the pump is coupled to the plasma chamber to evacuate the chamber, the workpiece support holds workpiece, the electrode assembly in the chamber comprises a plurality of wires extending laterally through the plasma chamber between the top plate of the plasma chamber and the workpiece support, each wire comprising a cylindrical insulator A conductor surrounded by a shell, wherein the plurality of filaments includes first multifilaments and second multifilaments, the second multifilaments are arranged in an alternating pattern with the first multifilaments, the first bus is coupled to the The first multifilament, the second bus is coupled to the second multifilament, the RF power supply applies an RF signal to the electrode assembly in the chamber, and the at least one RF switch is configured to controlably connect the first bus to the following One of each is electrically coupled and decoupled: i) ground, ii) RF power or iii) the second bus.

Implementations can include one or more of the following features.

The at least one RF switch may comprise a plurality of RF switches connected in parallel between the first bus and one of: i) ground, ii) RF power or iii) a second bus.

At least one RF switch can be configured to controllably electrically couple and decouple the first bus from the second bus. The at least one RF switch may comprise a plurality of switches connected in parallel between different pairs of locations on the first bus and the second bus to controllably electrically couple and decouple the first bus from the second bus.

The at least one RF switch may include a first switch configured to controllably electrically couple and decouple the first bus line from ground, and at least one second RF switch configured to The second bus is controllably electrically coupled and decoupled from ground. The at least one RF switch may include a first plurality of switches connected in parallel between different locations on the first bus and ground, and the at least one second switch may include a first plurality of switches connected in parallel between different locations on the second bus and ground. connected second plurality of switches. Different locations on the first bus can include opposite ends of the first bus, and different locations on the second bus can include opposite ends of the second bus.

The at least one RF switch may include a first plurality of switches connected in parallel between different locations on the first bus and the RF power supply, and the at least one second switch may include between different locations on the second bus and the RF power supply. A second plurality of switches connected in parallel between them. Different locations on the first bus can include opposite ends of the first bus, and different locations on the second bus can include opposite ends of the second bus. The at least one RF switch may include a first plurality of switches connected in parallel between a different location on the first bus and the RF power supply, and the at least one second switch may include a different location on the second bus and ground A second plurality of switches connected in parallel between them. Different locations on the first bus can include opposite ends of the first bus, and different locations on the second bus can include opposite ends of the second bus.

The at least one RF switch includes a first switch configured to controllably electrically couple and decouple the first bus from the RF power source, and at least one second switch configured to controllably The second bus is electrically coupled and decoupled from the RF power supply.

Some implementations may include a third bus and a fourth bus, the third bus is coupled to the first multifilament, the fourth bus is coupled to the second multifilament, wherein the plurality of filaments have a plurality of first ends and a plurality of second ends, and the first end of each corresponding filament is closer to the first side wall of the plasma chamber than the second end of the corresponding filament, and wherein the first bus is coupled to the first multifilaments of the first multifilament the first end, the second bus is coupled to the first ends of the second multifilament, the third bus is coupled to the second ends of the first multifilament, and the fourth bus is coupled connected to the second ends of the second multifilament.

The at least one RF switch may be configured to controllably electrically couple and decouple the first bus from the second bus, and may include at least one second RF switch configured to controllably couple the first bus to the second bus. The third bus is electrically coupled and decoupled from the fourth bus.

The at least one RF switch may include a first switch configured to controllably electrically couple and decouple the first bus line from ground, and may include at least one second RF switch configured via The third bus is configured to controllably electrically couple and decouple the third bus from ground.

The RF source can be coupled to the fourth bus through a first tap and to the second bus through a second tap.

Certain implementations can include at least one third RF switch configured to controllably couple and decouple the third bus from ground, and at least one fourth RF switch configured to controllably The ground electrically couples and decouples the fourth bus from ground. The at least one RF switch may comprise a first switch configured to controllably electrically couple and decouple the first bus to and from ground, and comprising at least one second RF switch, at least one third RF switch, the second RF switch is configured to controllably electrically couple and decouple the second bus to and from the RF source, the third RF switch is configured to controllably electrically couple and decouple the third bus to and from ground, And including at least one fourth RF switch configured to controllably electrically couple and decouple the fourth bus with the RF source.

The at least one RF switch includes a first switch configured to controllably electrically couple and decouple the first bus with the RF source, and includes at least one second RF switch, at least one third RF switch , the second RF switch is configured to controllably electrically couple and decouple the second bus to and from the RF source, and the third RF switch is configured to controllably electrically couple and decouple the third bus to and from the RF source coupled, and includes at least one fourth RF switch configured to controllably electrically couple and decouple the fourth bus to and from the RF source.

In another aspect, a plasma reactor includes a chamber body, a gas distributor, a pump, a workpiece support, an electrode assembly in the chamber, a bus, an RF power supply, and a plurality of RF switches, the chamber body has an interior space, the The interior space provides a plasma chamber, the gas distributor delivers process gas to the plasma chamber, the pump is coupled to the plasma chamber to evacuate the chamber, the workpiece support holds a workpiece, and an electrode assembly within the chamber comprising a plurality of wires extending laterally through the plasma chamber between the ceiling of the plasma chamber and the workpiece support, each wire comprising a conductor surrounded by a cylindrical insulating shell, the bus External to the chamber and coupled to opposite ends of the plurality of wires, the RF power supply applies an RF signal to the electrode assembly within the chamber, the plurality of RF switches configured to controllably connect a plurality of different locations on the bus to the following One of each is electrically coupled and decoupled: i) ground or ii) the RF power supply.

Certain implementations may have one or more of the following advantages. Improves plasma uniformity. Improves the repeatability of the plasma process. Can reduce metal pollution. Particle generation can be reduced. Reduces damage from plasma charging. The uniformity of the plasma can be maintained under different process operating conditions. Plasma power coupling efficiency can be improved. For a given size workpiece, the plasma field size can be reduced. It can improve the yield of plasma process. Workpieces may be successively carried through the plurality of chambers while remaining on the support. Relative velocity effects during plasma exposure can be compensated, thus improving intra-wafer uniformity. The effect of local non-uniformity in the plasma region can be reduced by switching, thereby improving intra-wafer uniformity. A low impedance RF ground can be provided. Particle generation can be reduced. Reduces damage from plasma charging. The uniformity of the plasma can be maintained under different process operating conditions. Plasma power coupling efficiency can be improved. A grounded top electrode that can be integrated with the gas distribution showerhead is used to introduce the gas in a uniform manner without unwanted gas breakdown in the showerhead holes.

In a conventional plasma reactor, the workpiece remains stationary within the reaction chamber. A plasma region is created above the stationary workpiece, which then treats the workpiece surface. However, certain plasma processing applications may benefit from moving the workpiece through the plasma zone, ie relative motion between the plasma zone and the workpiece. Also, for some tools, the substrate is moved between different chambers for a series of processing steps.

One method of achieving relative motion between the workpiece and the plasma region is by placing the workpiece on a workpiece support that moves along a linear path, such as a conveyor belt. In such a configuration, the workpiece can make a single pass in one direction through the plasma region and exit the chamber on the other side. This may be advantageous for certain sequential processes where a workpiece travels through multiple chambers of different types as part of the manufacturing process.

Another way to achieve relative motion between the workpiece and the plasma region is by placing the workpiece on a rotating workpiece support. The ability of the rotating workpiece support to pass through the plasma region multiple times without changing the direction of travel can increase throughput because the workpiece support does not need to continuously change its direction of travel. However, if the support is rotated, different regions of the workpiece may move at different speeds relative to the regional plasma.

In conventional CCP sources, plasma uniformity is generally determined by electrode size and distance between electrodes, as well as gas pressure, gas composition, and applied RF power. At higher radio frequencies, additional effects may become significant or even dominate the non-uniformity due to the presence of standing waves or skin effects. This additional effect becomes more pronounced at higher frequencies and plasma densities.

Plasma uniformity in conventional ICP sources is generally determined by the configuration of the ICP coil, including its size, geometry, distance to the workpiece and associated RF window position, as well as gas pressure, gas composition and power. In the case of multiple coils or coil segments, the current or power distribution and their relative phases can also be significant factors if driven at the same frequency. Due to the skin effect, power deposition tends to occur within a few centimeters below or near the ICP coil, and this localized power deposition often results in process non-uniformities that reflect the coil geometry. This plasma inhomogeneity results in potential differences across the workpiece, which can also lead to plasma charging damage (such as transistor gate dielectric cracking).

Large diffusion distances are generally required to improve the uniformity of the ICP source. However, conventional ICP sources with thick RF windows are generally inefficient at high gas pressures due to low power coupling, which allows high drive currents, resulting in high resistive power losses. Conversely, the electrode assembly inside the chamber need not have an RF window, but only a cylindrical shell. This can provide better power coupling and higher efficiency.

In a plasma chamber with a moving workpiece support, the moving workpiece support can be DC grounded through, for example, a rotary mercury coupler, brushes, or slip rings. However, a moving workpiece support may not be adequately grounded at radio frequencies. The RF ground path should have a much lower impedance than the plasma to make it an adequate RF ground. Lack of adequate RF ground paths can make it difficult to control ion energy at the workpiece and reduce process repeatability.

Therefore, there is a need for a plasma source that can efficiently generate a uniform plasma with desired properties (plasma density, electron temperature, ion energy, dissociation, etc.) resistance (such as pressure, power, gas composition); it has stable and repeatable electrical performance even when the workpiece moves; and it does not generate excessive metal contamination or particles. One or more of these properties may be better provided by the electrode assembly within the chamber.

Figure 1 is a schematic side view of an example of a processing tool. The processing tool 100 has a chamber body 102 surrounding an interior space 104 . The interior volume 104 may be cylindrical, such as for receiving a circular workpiece support. At least part of the interior space serves as a plasma chamber or plasma reactor. The chamber body 102 has supports 106 for providing mechanical support to various components within the interior volume 104 . For example, support 106 may provide support for top electrode 108 . The top electrode may be suspended within the interior space 104 and may be spaced apart from, adjoining, or form part of the top plate. Certain portions of the sidewalls of the chamber body 102 may be grounded independently of the top electrode 108 .

Gas distributor 110 is located near the ceiling of the plasma reactor portion of processing tool 100 . In some implementations, the gas distributor 110 is integrated with the top electrode 108 as a single component. The gas distributor 110 is connected to a gas supply 112 . The gas supply 112 delivers one or more process gases to the gas distributor 110, the composition of which may depend on the process to be performed, such as deposition or etching.

A vacuum pump 113 is coupled to the interior volume 104 to evacuate the processing tool. For some processes, the chamber operates in the Torr range, and the gas distributor 110 supplies argon, nitrogen, oxygen, and/or other gases.

A workpiece support 114 for supporting a workpiece 115 is positioned in the processing tool 100 . The workpiece support 114 has a workpiece support surface 114 a facing the top plate of the processing tool 100 . For example, the workpiece support surface 114a may face the top electrode 108 . The workpiece support 114 is operable to rotate about an axis 150 . For example, actuator 152 may rotate drive shaft 154 to rotate workpiece support 114 . In some implementations, the axis 150 is coincident with the center of the workpiece support 114 .

In some implementations, the workpiece support 114 includes a workpiece support electrode 116 inside the workpiece support 114 . In some implementations, the workpiece support electrode 116 may be grounded or connected to a grounded impedance or circuit. In some implementations, the RF bias power generator 142 is coupled to the workpiece support electrode 116 through an impedance match 144 . The workpiece support electrode 116 may additionally include an electrostatic chuck, and a workpiece bias voltage supply 118 may be connected to the workpiece support electrode 116 . The RF bias power generator 142 may be used to generate the plasma, control the electrode or sheath voltage, or control the ion energy of the plasma.

Additionally, the workpiece support 114 may have internal channels 119 for heating or cooling the workpiece 115 . In some implementations, an embedded resistive heater may be disposed inside the interior channel 119 .

In some implementations, the workpiece support 114 is heated by radiation, convection, or conduction from a heating element located within the bottom interior volume 133 .

Intra-chamber electrode assembly 120 is positioned in interior space 104 between top electrode 108 and workpiece support 114 . This electrode assembly 120 includes one or more coplanar wires 300 extending laterally in the chamber above the support surface 114a of the workpiece support 114 . At least a portion of the coplanar filaments of the electrode assembly 120 above the workpiece support 114 extend parallel to the support surface 114a. Although the left side of FIG. 1 depicts the wire 300 parallel to the direction of motion of the workpiece 115 (in and out of the page), the wire 300 may be at a non-zero angle relative to the direction of motion, such as substantially perpendicular to the direction of motion.

A top gap 130 is formed between the top electrode 108 and the inner chamber electrode assembly 120 . A bottom gap 132 is formed between the workpiece support 114 and the intra-chamber electrode assembly 120 .

The inner space 104 may be divided by barriers into one or more regions 101a, 101b, at least one of which functions as a plasma chamber. The barrier defines one or more openings 123 above the workpiece support. In some implementations, electrode assembly 120 is positioned within opening 123 . In some implementations, an electrode assembly is placed over opening 123 . In some implementations, the barrier is integrally formed by the support 106 , and the opening 123 is formed on the support 106 . In some implementations, the opening 123 formed on the support 106 is configured to support the electrode assembly 120 .

The electrode assembly 120 is driven by an RF power source 122 . The RF power source 122 may power the one or more coplanar filaments of the electrode assembly 120 at a frequency ranging from 1 MHz to over 300 MHz. For some processes, the RF power supply 120 provides 100W to greater than 2kW of total RF power at a frequency of 60MHz.

In some implementations, it may be desirable to select the bottom gap 132 to allow plasma generated radicals, ions, or electrons to interact with the workpiece surface. The choice of clearance depends on the application and on the method of operation. For some applications where radical flux (but very low ion/electron flux) is required to be delivered to the workpiece surface, operation at larger gaps and/or higher pressures is an option. Operation at smaller gaps and/or lower pressures is an option for other applications that require the delivery of free radical flux and substantial plasma ion/electron flux to the workpiece surface. For example, in some low-temperature plasma-enhanced ALD processes, free radicals from the process gas are necessary for the deposition or treatment of ALD films. Free radicals are atoms or molecules with unpaired valence electrons. Free radicals are usually highly chemically reactive towards other substances. The reaction of free radicals with other chemicals often plays an important role in film deposition. However, free radicals are generally short-lived due to their high chemical activity and thus cannot be transported very far during their lifetime. Placing a free radical source (ie, the chamber electrode assembly 120 as a plasma source) close to the surface of the workpiece 115 can increase the supply of free radicals to the surface to improve the deposition process.

The life cycle of free radicals usually depends on the stress of the surrounding environment. Thus, the height of the bottom gap 132 to provide a satisfactory concentration of free radicals can be varied depending on the expected chamber pressure during operation. In some implementations, the bottom gap 132 is less than 1 cm if the chamber is operated at a pressure in the range of 1 to 10 Torr. In other (lower) temperature plasma-enhanced ALD processes, exposure to plasma ion flux (with concomitant electron flux) and radical flux may be necessary to deposit and process ALD films. In some implementations, the bottom gap 132 is less than 0.5 cm if the chamber is operated at a pressure in the range of 1-10 Torr. Lower operating pressures allow operation at larger clearances due to the lower volumetric recombination ratio with respect to distance. In other applications, such as etching, lower operating pressures (less than 100mTorr) are typically used and gaps can be increased.

In such applications where the bottom gap 132 is small, the plasma generated by the electrode assembly 120 may have significant inhomogeneity between the wires, which may be detrimental to the uniformity of treatment of the workpiece. By moving the workpiece through a plasma with spatial inhomogeneity, this can be mitigated by temporal averaging effects (i.e., the cumulative plasma dose received by any given region of the workpiece after a single pass through the plasma is substantially similar) Effect of plasma spatial inhomogeneity on process.

The top gap can be chosen to be large enough to allow plasma to develop between the electrode assembly and the top electrode (or top of the chamber) within the chamber. In some implementations, the top gap 130 may be between 0.5-2 cm, such as 1.25 cm, if the chamber is operated at a pressure in the range of 1-10 Torr.

The top electrode 108 can be configured in various ways. In some implementations, the top electrode is connected to RF ground 140 . In some implementations, the top electrode is electrically isolated ("floating"). In some implementations, the top electrode 108 is biased at a bias voltage. The bias voltage can be used to control the properties of the generated plasma, including ion energy. In some implementations, the top electrode 108 is driven with an RF signal. For example, driving the top electrode 108 relative to the already grounded workpiece support electrode 116 may increase the plasma potential at the workpiece 115 . The increased plasma potential can increase the ion energy to a desired value.

The top electrode 108 may be formed from different process compatible materials. Various criteria for process calculability include material resistance to process gas etching and resistance to sputtering from ion impact. Furthermore, process-compatible materials preferentially form volatile or gaseous compounds (which can be evacuated by vacuum pump 113 ) and do not form particles that could contaminate workpiece 115 in the case of material quantities that are etched. Therefore, in some implementations, the top electrode is made of silicon. In some implementations, the top electrode is made of silicon carbide.

In some implementations, top electrode 108 may be omitted. In such implementations, the RF ground path may be provided by the workpiece support electrode, a subset of coplanar filaments of the electrode assembly 120, or by a chamber wall or other ground-referenced surface in communication with the plasma. supply.

In some implementations, the fluid supply 146 circulates fluid through channels in the electrode assembly 120 within the chamber. In some implementations, a heat exchanger 148 is coupled to the fluid supply 146 to remove heat or supply heat to the fluid.

Depending on the chamber configuration and the process gases supplied, the plasma reactor in the processing tool 100 can provide an ALD tool, an etch tool, a plasma processing tool, a plasma-enhanced chemical vapor deposition tool, a plasma doping tool, or a plasma Surface cleaning equipment.

FIG. 2A is a schematic top view of an example of a processing tool 200 . Processing tool 200 is similar to processing tool 100 except as described. The processing tool 200 has a cylindrical chamber body 202 , an interior space 204 having a cylindrical shape, a support 206 , an electrode assembly 220 and a precursor station 260 . The support 206 is located at the center of the treatment tool 200 and forms a plurality of radial partitions 270 to divide the interior space 204 into multiple treatment areas. For example, multiple treatment regions may be configured to have a wedge-shaped shape, such as a circular cross-section or an equilateral triangle, or may be cut away at the apex. The processing areas can be configured in various ways to achieve the various functions desired for the operation of the processing tool 200 .

The precursor processing region is configured to process workpiece 115 with one or more precursors, such as for an ALD process. For example, first precursor station 260a positioned within precursor processing region 280a may be configured to flow or pump chemical precursor A such that workpiece 115 is processed as workpiece 115 moves under precursor station 260a. Then, the precursor station 260 a can treat the workpiece 115 with the chemical precursor B to prepare the surface of the workpiece 115 , such as surface treatment for ALD film-forming plasma.

In some implementations, the precursor processing region 280 includes a plurality of sub-regions with respective precursor stations 260 for respective chemical precursors. In some implementations, the sub-regions are arranged sequentially along the path of the workpiece 115 . In some implementations, movement of workpiece 115 is stopped during precursor surface treatment. In some implementations, the workpiece 115 is continuously moved through the precursor processing region 280 .

The gas isolation zone 281 is configured to provide spatial isolation of individual processing environments of a plurality of processing regions, such as a first processing region and a second processing region. The gas isolation zone 281 may include a first pumping zone 282 , a purge zone 283 , and a second pumping zone 284 , each zone separated by a respective radial partition 270 . In conventional systems, isolation of the processing environment may be provided by a hermetic seal between the first and second processing regions. However, due to the rotating workpiece support 114, it may not be practical to provide such a seal. Conversely, an isolation level sufficient for plasma processing applications such as ALD can be provided by interposing a gas isolation region 281 between the first and second processing regions.

Referring to FIG. 2B , a cross-sectional view of a portion of the processing tool 200 along section line B is shown. During operation, a first pumping zone 282 adjacent to a first processing zone (eg, precursor processing zone 280a ) generates a negative pressure differential relative to the first processing zone. For example, a vacuum pump can be used to create a negative pressure differential. The negative pressure differential causes the process gas leaked from the first process area to be pumped through the first pumping area 282, as indicated by the arrows. Similarly, a second pumping zone 284 adjacent to a second treatment zone provides a negative pressure differential relative to the second treatment zone, such as plasma treatment zone 285a.

A purge zone 283 located between the first pumping zone 282 and the second pumping zone 284 supplies purge gas. Examples of purge gases include inert gases such as argon and nitrogen. Due to the negative pressure differential created by the first and second pumping zones, the purge gas supplied by the purge zone 283 is pumped to the first and second pumping zones, as indicated by the arrows. The presence of the purge gas prevents the respective processing gases of the first and second processing regions from mixing with each other, which could cause unwanted chemical reactions leading to unwanted deposition, etching or A residue is produced.

The first gap height H ₁ provides clearance between the radial spacer 270 and the workpiece support 114 . The first gap height may be determined based on providing sufficient clearance for passage of workpiece 115 while reducing leakage of process gases into pumping regions 282 and 284 . For example, the first gap height may be in the range of 2-4mm, such as 3mm.

Referring back to FIG. 2A , the plasma treatment region 285 is configured to treat the workpiece 115 with plasma. For example, electrode assembly 220a located within plasma processing region 285a may generate a plasma for processing the surface of workpiece 115 . The precursor-treated surface of the workpiece 115 that has moved through the gas isolation region 281 is treated with the plasma generated by the electrode assembly 220a. In some implementations, the plasma treatment completes the deposition cycle of a single atomic layer of the first ALD film.

In some implementations, electrode assembly 220 is formed in a rectangle as shown. In some implementations, the electrode assembly 220 is formed in a wedge shape.

Referring back to FIG. 2B , in some implementations, the process gas for the plasma processing region 285 is provided through the gas inlet 210 formed adjacent to the electrode assembly 220 . Specifically, the gas inlet 210 may be disposed at an edge of the gas isolation region 281 adjacent to the plasma processing region 285a. For example, a channel may be formed between one of the spacers 270 and the outer wall 221 of the electrode assembly 220a.

The second gap height H ₂ provides clearance between the electrode assembly 220 and the workpiece support 114 . The second gap height may be determined based on providing sufficient clearance for workpiece 115 to pass through and process gas to the interior region of electrode assembly 220 while reducing process gas leakage into pumping regions 282 and 284 . For example, the second gap height may be in the range of 1-3mm, such as 2mm. In some implementations, the gas inlet is formed on the entry side of the workpiece 115 . In some implementations, the gas inlet is formed toward the radially outer edge of the electrode assembly, which is near the chamber wall 202 . In some implementations, the gas inlet is formed toward the center of the workpiece support 114 , such as near the axis 150 .

In some implementations, the top electrode 208 is formed as part of or supported by the electrode assembly 220a. For example, top electrode 208 may be supported by top plate 221a.

Referring to FIG. 2C , a cross-sectional view of a portion of the processing tool 200 along section line C is shown. In some implementations, as shown, support 206 is configured to provide mechanical support for electrode assemblies 220a and 220b.

In some implementations, the processing tool 200 includes a second precursor processing region 280b and a second plasma processing region 285b. Regions 280b and 285b may be configured to deposit a second ALD film. In some implementations, the second ALD film is the same as the first ALD film deposited in regions 280a and 285a. Such an implementation can improve the deposition rate of a single ALD film. In some implementations, the second ALD film is different than the first ALD. In such an implementation, two different ALD films may be deposited in an alternating fashion. In general, processing tool 200 may be configured to deposit 2, 3, 4 or more types of ALD films.

In general, workpiece 115 may be made in a single pass or may be passed through the processing area multiple times. For example, the direction of rotation may be alternated for multiple passes over a particular treatment area.

In general, treatment areas can be arranged in any order. For example, a precursor treatment zone may be followed by 2 different plasma treatment zones with the same or different plasma properties.

With respect to Figure 1 or Figures 2A-2C, the electrode assembly 120 or 220 includes one or more coplanar wires 300 extending laterally in the chamber above the support surface of the workpiece support. At least a portion of the coplanar filaments of the electrode assembly above the workpiece support extend parallel to the support surface. Wire 300 may be at a non-zero angle relative to the direction of motion, such as substantially perpendicular to the direction of motion.

The electrode assembly may include sidewalls 221 surrounding the electrode plasma chamber region. The sidewalls may be formed of a process compatible material, such as quartz. In some implementations, the wire protrudes laterally from the sidewall. In some implementations, the ends of the wire 300 extend out of the top plate of the electrode assembly and turn to provide a portion parallel to the support surface of the workpiece (see FIG. 2C ).

3A-C are schematic illustrations of various examples of wires of an electrode assembly within a chamber. Referring to FIG. 3A , a wire 300 of the electrode assembly 120 within the chamber is shown. The wire 300 includes a conductor 310 and a cylindrical shell 320 that surrounds and extends along the conductor 310 . Channel 330 is formed by the gap between conductor 310 and cylindrical shell 320 . Cylindrical housing 320 is formed from a process compatible non-metallic material. In some implementations, the cylindrical shell is semiconducting. In some implementations, the cylindrical shell is insulating.

Conductor 310 may be formed of various materials. In some implementations, the conductor 310 is a solid wire, such as a single solid wire having a diameter of 0.063". Alternatively, the conductor 310 may be provided by multiple strands of stranded wire. In some implementations, the conductor contains 3 parallel 0.032" strands . Stranded wires can reduce RF power loss through the skin effect. In some implementations, the conductor 310 is formed of Litz wire, which can further reduce skin effect.

Use materials with high electrical conductivity (eg higher than 10 ⁷ Siemen/m), which reduces resistive power loss. In some implementations, conductor 310 is made of copper or a copper alloy. In some implementations, the conductors are made of aluminum.

Unwanted material sputtering or etching can lead to process contamination or particle formation. Whether the intra-chamber electrode assembly 120 is used as a CCP or as an ICP source, unwanted sputtering or etching may occur. Unwanted sputtering or etching can be caused by excess ion energy at the electrode surface. When operating as a CCP source, an oscillating electric field around the cylindrical shell is required to drive the plasma discharge. Since the sputtering energy threshold of all known materials is below the corresponding minimum operating voltage of the CCP source, this oscillation causes either sputtering or etching of the material. When operating as an ICP source, the capacitive coupling of the wire 300 to the plasma generates an oscillating electric field at the nearby surface, which also causes sputtering of material. By using process compatible materials for the outer surfaces of the filament 300 exposed to the interior space 104 (eg, the cylindrical shell 320 ), problems caused by unnecessary material sputtering or etching can be mitigated.

In some implementations, the cylindrical shell 320 is formed of a process compatible material, such as silicon (eg, high-resistivity silicon), oxide material, nitride material, carbide material, ceramic material, or combinations thereof. Examples of oxide materials include silicon dioxide (eg, silica, quartz) and aluminum oxide (eg, sapphire). Examples of carbide materials include silicon carbide. For some chemical environments, including fluorinated or fluorocarbon-containing environments, ceramic materials or sapphire may be required. In chemical environments containing ammonia, dichlorosilane, nitrogen, and oxygen, silicon, silicon carbide, or quartz may be required.

In some implementations, the cylindrical shell 320 has a thickness of 0.1 mm to 3 mm, such as 2 mm.

In some implementations, fluid is provided in channel 330 . In some implementations, the fluid is a non-oxidizing gas to purify oxygen to mitigate oxidation of the conductor 310 . Examples of non-oxidizing gases are nitrogen and argon. In some implementations, a non-oxidizing gas is continuously flowed through channel 330 , such as by fluid supply 146 , to remove residual oxygen or water vapor.

Heating the conductor 310 can make the conductor more susceptible to oxidation. The fluid may provide cooling to the conductor 310 that may be heated from the supplied RF power. In some implementations, fluid is circulated through channel 330, such as by fluid supply 146, to provide forced convective temperature control, such as cooling or heating.

In some implementations, the fluid may be at near or above atmospheric pressure to prevent breakdown of the fluid. For example, gas decomposition or unwanted plasma formation in the tube can be prevented by providing a fluid pressure higher than 100 Torr.

Referring to Figure 3B, in some implementations of wire 300, conductor 310 has a coating. In some implementations, the coating is an oxide of the material forming the conductor (eg, aluminum oxide on an aluminum conductor). In some implementations, the coating is silicon dioxide. In some implementations, the coating is formed in situ in the plasma reactor of the processing tool 100, such as by the reaction of silane, hydrogen, and oxygen to form a silicon dioxide coating. In-situ coatings can be advantageous because in-situ coatings can be replenished upon etching or sputtering. In-situ coatings can have a thickness ranging from 100 nm to 10 μm.

Referring to FIG. 3C , in some implementations of wire 300 , conductor 310 is hollow, and hollow channel 340 is formed inside conductor 310 . In some implementations, hollow channel 340 can carry a fluid, as described in FIG. 3A . A coating of process compatible material may cover conductor 310 to provide cylindrical shell 320 . In some implementations, the coating is an oxide of a conductor-forming material (such as alumina on aluminum conductors). In some implementations, the hollow conductor 310 has an outer diameter of 2 mm with a wall thickness of 0.5 mm.

Figure 4A is a schematic illustration of a portion of an electrode assembly within a chamber. Intra-chamber electrode assembly 400 includes a plurality of coplanar wires 300 attached at support 402 . The electrode array is formed from a plurality of coplanar filaments 300 . The electrode assembly 400 may provide the electrode assembly 120 . In some implementations, the wires 300 extend parallel to each other at least over regions corresponding to the workpiece that have been processed.

The wires 300 are separated from each other by a wire pitch 410 . The spacing 410 can affect plasma uniformity. If the pitch is too large, the wires can create shadowing and non-uniformity. On the other hand, if the spacing is too small, the plasma cannot move between the top gap 130 and the bottom gap 132, and the non-uniformity will increase or the radical density will decrease.

In general, the desired value for wire spacing 410 depends on several factors. Examples of these factors include chamber pressure, RF power, distance between wire 300 and workpiece 115, and process gas composition. For example, the wire spacing 410 may be increased when operating at lower pressures (eg, below 2 Torr) and with large distances (eg, greater than 3 mm) between the wire and workpiece.

In some implementations, wire spacing 410 is uniform across assembly 400 . The wire spacing 410 may range from 3mm to 20mm, such as 8mm.

4B-C are schematic cross-sectional views of electrode assemblies in chambers with different plasmonic domain states. Referring to FIG. 4B , under some operating conditions, the plasmonic region 412 surrounds the filament 300 . Examples of such operating conditions may include driving all filaments with the same RF signal (ie, "monopolar"), with a grounded top electrode. The plasma region 412 has an upper plasma region 414 and a lower plasma region 416 . The upper plasma region 414 may be located at the top gap 130 and the lower plasma region 416 may be located at the bottom gap 132 . As shown in FIG. 4B , the upper plasma region 414 and the lower plasma region 416 form a continuous plasma region 412 through the gap connection between the filaments 300 . This continuity of plasma region 412 is expected because regions 414 and 416 "communicate" with each other through the exchange of plasma. The exchange of plasma helps maintain electrical balance between the two regions, which contributes to plasma stability and repeatability.

Referring to FIG. 4C, in this state, the upper plasma region 414 and the lower plasma region 416 are not connected to each other. Such "pinching" of the plasma region 412 is undesirable for plasma stability. The shape of the plasma region 412 can be changed by various factors to remove plasma region discontinuity or improve plasma uniformity.

In general, regions 412, 414, and 416 can have a wide range of plasma densities, and are not necessarily uniform. Furthermore, the discontinuity between the upper plasma region 414 and the lower plasma region 416 shown in FIG. 4C represents a substantially low plasma density relative to these two regions, and is not necessarily a complete absence of plasma in the gap. pulp.

Under some operating conditions, such as the top electrode is absent or floating, and the workpiece support electrode is grounded, the plasma region 414 may not form, or have a low plasma density.

In some implementations, the intra-chamber electrode assembly 400 can include first and second sets of wires 300 . The first and second groups may be spatially arranged such that the filaments alternate between the first and second groups. For example, a first group may include wire 302 and a second group may include wires 300 and 304 . The first group can be driven by the first terminal 422a of the RF power supply 422 and the second group can be driven by the second terminal 422b of the RF power supply 422 . RF power supply 422 may be configured to provide a first RF signal at terminal 422a and a second RF signal at terminal 422b. The first and second RF signals may have the same frequency and stable phase relationship as each other. For example, the phase difference between the first and second RF signals may be 0 degrees or 180 degrees. In some implementations, the phase relationship between the first and second RF signals provided by the RF power supply 422 can be adjustable between 0 and 360°. In some implementations, RF supply 422 may include two individual RF power supplies that are phase locked to each other.

Under some operating conditions, for example, when the phase difference between the first and second RF signals is 180, the resulting plasma region may be concentrated between the filaments.

The top gap 130 is a factor that affects the shape of the plasmonic region. Reducing the top gap 130 generally results in a reduction in the plasma density in the upper plasma region 414 when the top electrode 108 is grounded. The specific value of the top gap 130 can be determined based on computer simulations of the plasma chamber. For example, the top gap 130 may be 3mm to 8mm, such as 4.5mm.

The bottom gap 132 is a factor that affects the shape of the plasma region. Reducing the bottom gap 132 generally results in a lower plasma density in the lower plasma region 416 when the workpiece support electrode 116 is grounded. The specific value of the bottom gap 132 can be determined based on computer simulations of the plasma chamber. For example, the bottom gap 132 may be 3 mm to 9 mm, such as 4.5 mm.

In general, chamber pressure is the factor that affects the shape of the plasma region.

5A and 5B are schematic diagrams of various examples of electrode assembly configurations within a chamber. Referring to Figures 5A and 5B, in some implementations, the electrode assembly 106 can include a first set of conductors 120a and a second set of conductors 120b. At least within the plasma chamber 104, the first and second sets of conductors 120a, 120b may be arranged in an alternating pattern. The first group can be driven by the first terminal 122a of the RF power source 122 and the second group can be driven by the second terminal 122b of the RF power source 122 . RF power supply 122 may be configured to provide a first RF signal at terminal 122a and a second RF signal at terminal 122b. The first and second RF signals may have the same frequency and stable phase relationship as each other. For example, the phase difference between the first and second RF signals may be 180 degrees. By driving the conductors 120a, 120b with RF signals having a 180 degree phase difference, the resulting plasma distribution may be less sensitive to imperfect RF grounding of the electrode 116 . Without being bound by any particular theory, this may be because the RF current returns through adjacent electrodes due to the differential nature of the drive signal. In some implementations, the phase relationship between the first and second RF signals provided by the RF power supply 122 can be adjustable between 0 and 360°.

In order to generate the signal, the unbalanced output signal from the oscillator of the RF power supply may be coupled to a balun (balance-unbalance transformer) 124, the balun 124 in Balanced signals are output on terminals 122a, 122b. Alternatively, RF supply 122 may comprise two individual RF power supplies that are phase locked to each other.

Referring to FIG. 5A, the electrode assembly 120 includes a first electrode subassembly 510 including a first set of conductors 120a and a second electrode subassembly 520 including a second set of conductors 120b. The conductor 120 a of the first electrode subassembly 510 and the conductor 120 b of the second electrode subassembly 520 are interdigitated.

Subassemblies 510 , 520 each have a plurality of parallel conductors 120 a , 120 b extending across chamber 104 . Every other electrode 120 , such as electrode 120 a , is connected to a first bus 530 on one side of the chamber 104 . The remaining (alternating) electrodes 120 , ie electrodes 120 b , are each connected to a second bus 540 on the other side of the chamber 104 . The ends of the respective conductors 120 that are not connected to the RF power supply bus may remain unconnected, eg, floating.

The first bus 530 may be connected to the first terminal 122a, and the second bus may be connected to the second terminal 122b. The first electrode subassembly 510 and the second electrode subassembly 520 are oriented parallel to each other such that the conductors of the subassemblies 510 and 520 are parallel to each other.

In some implementations, the bus lines 530 , 540 connecting the conductors 120 a , 120 b are located outside the interior space 104 . This is better for improving uniformity within the chamber 104 . However, in some implementations, the bus lines 530 , 540 connecting the conductors 120 a , 120 b are located within the interior space 104 .

FIG. 5B shows an electrode assembly 106 similar in implementation to that shown in FIG. 5A, but the ends of the respective conductors 120 not connected to the RF power supply bus may be grounded, such as a bus connected to ground. For example, electrode 120a may be connected to third bus 550 on the side of chamber 104 as second bus 540 , and electrode 120b may be connected to fourth bus 560 on the same side of chamber 104 as first bus 530 . Each bus 550, 560 can be grounded through an adjustable impedance 580 (eg, an impedance matching network).

For FIG. 5A or 5B , optionally, a low frequency common mode bias may be applied between the electrode subassemblies 510 , 520 . This can controllably increase the plasma potential.

5C depicts the electrode assembly 106 within the chamber, which includes a first electrode subassembly 522 and a second electrode subassembly 532 configured such that the wires of the subassemblies 522 and 532 are extend at a non-zero angle to each other (eg, perpendicular to each other).

The intra-chamber electrode assembly 106 can be driven with the RF signal in various ways. In some implementations, subassembly 522 and subassembly 532 are driven with the same RF signal relative to RF ground. In some implementations, subassembly 522 and subassembly 532 are driven with differential RF signals. In some implementations, subassembly 522 is driven with an RF signal, and subassembly 532 is connected to RF ground.

FIG. 5D shows the electrode assembly 106 in the chamber, which includes a first electrode subassembly 524 and a second electrode subassembly 534 , the first electrode subassembly 524 and the second electrode subassembly 534 overlap. The first electrode subassembly 524 and the second electrode subassembly 534 each have a plurality of parallel wires 300 connected by bus lines 530 , 540 , 550 and 560 at respective ends of the respective bus lines. The first electrode subassembly 524 and the second electrode subassembly 534 are configured such that the filaments of the subassemblies 524 and 534 are parallel to each other, the filaments of the subassemblies 524, 534 being arranged in an alternating pattern.

The intra-chamber electrode assembly 106 can be driven with the RF signal in various ways. In some implementations, subassembly 524 and subassembly 534 are driven with the same RF signal relative to RF ground. In some implementations, subassembly 524 and subassembly 534 are driven with differential RF signals. In some implementations, subassembly 524 is driven with an RF signal, and subassembly 534 is connected to RF ground.

In some implementations, the inner chamber electrode assembly 106 is driven with an RF signal in a single-ended manner using the center feed 590 . The center feed 590 is connected at the center to an X-shaped current splitter 592 . The four corners of subassemblies 524 and 534 are connected to X-shaped current splitter 592 using vertical feed structures.

In general, when adequate RF grounding cannot be provided (such as through rotary mercury couplers, brushes, or slip rings), the differential Actuation can improve plasma uniformity or process repeatability.

FIG. 6A is a schematic top view of an interior region of an example of a processing tool 650 . In processing tool 650 , workpiece support 114 is rotated about axis 150 , and the rotation of workpiece support 114 causes workpiece 115 to move beneath electrode assembly 600 through a region of plasma generated by electrode assembly 600 . Unless otherwise noted, processing tool 650 is similar to processing tool 200 and electrode assembly 600 is similar to electrode assembly 400 .

As workpiece 115 rotates about axis 150 through the plasma region, the velocities experienced by different surface regions of the workpiece vary as a function of their radial distance from axis 150 . For example, regions of the workpiece farther from the axis 150 move faster than regions closer to the axis 150 . For a rectangular or linear plasma zone, regions of the workpiece further away from the axis 150 experience correspondingly shorter residence times in the plasma zone. This radial non-uniformity in dwell time results in non-uniformity in the amount of plasma received on the workpiece, causing unwanted process non-uniformity.

One way to compensate for the aforementioned dwell time non-uniformity is to vary the local density of the plasma region in proportion to the local velocity of the wafer. For example, the local plasma density may increase in proportion to the radial distance from the axis 150 . By increasing the plasma density at regions of higher local velocity, these regions receive an equal amount of plasma in their respective shorter residence times. However, the spatial inhomogeneity of the plasma density may lead to non-uniform charging of the workpiece surface, thereby generating a potential difference across the workpiece surface. Depending on grain size and component sensitivity, sufficiently large potential differences (e.g. greater than 2 V, 5 V, 10 V, 15 V, 25 V) on the surface may cause damage to components fabricated on the workpiece, e.g. thin transistor gates Dielectric breakdown of the dielectric layer.

Another way to compensate for residence time non-uniformity is by changing the geometry of the plasma region. The geometry of the plasma zone can be varied such that a zone of higher local velocity travels through a correspondingly longer portion of the plasma zone to equalize the dwell times of different zones of the workpiece surface. For the configuration shown in Figure 6A, residence time equalization can be achieved with wedge-shaped plasma regions. In such a configuration, the radial increase in local velocity by moving away from the axis 150 can be counteracted by a proportional increase in the arc length of the wedge-shaped plasma region over each region.

The aforementioned wedge-shaped plasma regions may be formed by configuring the coplanar filaments and openings 627 of the electrode assembly 600 in various ways. One way is to configure the electrode array formed by the wires of the electrode assembly 600 in a wedge-shaped fashion. For example, the respective lengths of the individual coplanar filaments of the electrode array can be varied such that the overall profile of the electrode array defines a wedge shape. In some implementations, supports 206 can provide support at respective ends of the coplanar filaments of the electrode array.

Another way to form a wedge-shaped plasma region is to form a plasma region larger than the size of opening 627 by forming opening 627 to have a wedge shape and using an electrode array of electrode assembly 600 that is larger than opening 627 (eg, electrode assembly 400 ). A portion of the generated plasma region may then be blocked by the wedge-shaped opening to create a wedge-shaped plasma region. For example, support 206 may provide wedge-shaped opening 627 .

In general, various factors may affect the size of the wedge-shaped plasmonic region. In some applications, partial or incomplete plasma coverage on the workpiece surface can lead to unfavorable results. For example, workpiece 115 may contain components that are susceptible to charging damage, such as transistors with thin gate dielectric layers. In this case, the potential generated between the area of the workpiece 115 exposed to the plasma and the area not exposed to the plasma may cause dielectric collapse of the gate dielectric layer, causing permanent damage to the sensitive element . This problem can be mitigated by sizing the plasma region to be larger than the workpiece so that complete plasma coverage is achieved over the entire workpiece surface. In some implementations, adjusting the size of the plasma zone enables the workpiece to move through the plasma zone while maintaining complete plasma coverage.

In some implementations, such as where the plasma area is larger than the workpiece, the timing of the application of RF power to the electrode assembly 600 can be coordinated with the movement of the workpiece 115 to ensure uniform exposure to the plasma across the entire surface of the workpiece. For example, the plasma may be generated (ignited) after the entire workpiece moves under the opening 627 or electrode assembly 600, and turned off (extinguished) before the workpiece exits the plasma region. In this case, the plasmonic region need not be wedge-shaped.

However, generating large plasma regions (eg, greater than 300mm x 300mm) using electrode assembly 600 may be challenging in some circumstances. If the workpiece to be treated can tolerate incomplete plasma coverage on its surface, the size of the plasma zone can be adjusted to be smaller than the surface of the workpiece in one direction of the workpiece. For example, as shown in FIG. 6A , the wedge-shaped electrode assembly 600 (and thus the plasma region) is smaller than the workpiece diameter in the direction of travel of the workpiece 115, but larger in the radial direction relative to the axis 150 to achieve diameter. Complete coverage in all directions.

Other considerations for adjusting the size of the plasma zone include workpiece movement speed, target process rate, and target plasma exposure time to achieve a desired process duration or throughput.

In some implementations, the plasma can be coordinated with the movement of the workpiece to ensure that a stable plasma is established before the workpiece enters the plasma region. For example, in processes requiring a relatively short plasma exposure time, the time spent striking the plasma can be a significant portion of the total plasma exposure time. Because the plasma is relatively unstable during the impingement phase, the resulting process repeatability may suffer. By establishing a stable plasma prior to introducing the workpiece, the plasma exposure time and amount can be precisely controlled by controlling the velocity of the workpiece as it moves through the plasma region. For such implementations, regardless of whether the plasma zone is larger or smaller than the workpiece, it is advantageous if the plasma zone is tapered to compensate for differences in exposure time. In some implementations, the generated plasma is maintained over the processing of multiple workpieces.

Assuming that the processing tool 650 has a fixed plasma zone size, various process parameters can be controlled to achieve desired plasma processing characteristics. Examples of process parameters that may be controlled include process rate, exposure time, workpiece movement speed profile, number of plasma exposure passes, and total plasma exposure dosage. For example, the workpiece may pass through the plasma region multiple times, or may oscillate at a location within the plasma region.

6B is a schematic top view of an example of a wedge-shaped electrode assembly for generating a wedge-shaped plasma region. The wedge-shaped electrode assembly 600 has a plurality of coplanar wires 610 and a frame 620 . Electrode assembly 600 is similar to electrode assemblies 120, 220, and 400 unless otherwise noted. The frame 620 has a first end 602 , a second end 604 , a central angle θca, an inner radius R ₁ , an outer radius R ₂ and a bisector 605 . The first end 602 is the short end of the electrode assembly 600, sometimes referred to as the apex. The second end 604 is the longer end of the electrode assembly 600, sometimes referred to as the base. Unless otherwise noted, coplanar filaments 610 are similar to filaments 300 . Each coplanar filament 610 has a respective length L, a respective angle θ (theta) with respect to the bisector 605 . The length L is defined as the linear portion of the coplanar filament 610 in the region parallel to and adjacent to the workpiece support surface (eg, 114a). Each pair of adjacent coplanar filaments 610 is separated by a corresponding spacing S, defined as the center-to-center distance between adjacent filaments. For non-parallel filaments, the spacing S is defined as the smallest center-to-center spacing along the length of the pair of adjacent filaments.

There are various considerations in determining the angle theta of wire 610 . One consideration in determining the angle theta is the trajectory of the workpiece 115 as it moves beneath the electrode assembly 600 . In some cases, the plasma generated by electrode assembly 600 may have inhomogeneities in the plasma extending along the direction of filament 610 . For example, under certain operating conditions, there may be an elongated region of reduced plasma density between a pair of filaments 610 . If a spot on the workpiece surface follows a region of reduced plasma density, that spot will receive reduced plasma exposure, resulting in process non-uniformity. By arranging the filaments to have appropriate theta values (eg, less than or greater than 90°, but not including 90°), this tangential travel along regions of reduced plasma density can be reduced, thereby improving process uniformity. For example, by setting theta to 60°, a point on the workpiece surface passes under multiple wires, exposed to localized plasma regions of reduced and nominal density along the way, such that there is time averaging of the plasma exposure dose. In some implementations, the respective thetas of the plurality of coplanar filaments 610 are equal, ie, the filaments are parallel.

In some implementations, the respective θ of the wires 610 differ based on their respective positions within the electrode assembly 600 . For example, for the filaments near the apex 602 to the filaments near the base 604 of the assembly 600 , the respective theta increases monotonically to maintain equal lengths of the filaments 610 across the electrode assembly 600 . Having wires of equal length improves uniformity when the assembly 600 is operated as an ICP source.

Generally, the number of coplanar filaments 610 is determined by the size, theta, and spacing S of the plasma domain, so as to achieve the required properties of the plasma domain, such as plasma density and uniformity.

In general, spacing S may be determined based on the considerations discussed in FIG. 4 with respect to wire spacing 410 .

The frame 620 defines the shape of the electrode assembly 600 and the shape of the plasma region formed by the electrode assembly 600 . The inner radius, outer radius and central angle determine the dimensions of the wedge electrode, which in turn define the dimensions of the plasma region. The size of the frame can be determined based on the previous discussion regarding sizing the plasmonic region of FIG. 6B.

Frame 620 may be formed from different process compatible materials. Suitable process compatible materials include those described with respect to cylindrical shell 320, such as quartz. Other examples of process compatible materials include ceramics (eg alumina, aluminum nitride) and various silicon nitrides (eg SiN, Si ₃ N ₄ ).

Although frame 620 has been described with respect to wedge-shaped electrode assembly 600, wire 610 may be formed and arranged to have the described wedge shape without frame 620 to achieve a similar result.

An example of a wedge-shaped electrode assembly has the following design characteristics: R ₁ =91 mm, R ₂ =427 mm, center angle = 31°, theta = 60°, wire center to center spacing = 15 mm, number of wires = 20, frame material = quartz.

Referring to FIG. 6C , in some implementations, the frame 620 has a cutout 622 . Cutout 622 may be shaped to fit wedge-shaped top electrode 624 . The wedge-shaped top electrode 624 may be grounded or biased to a bias voltage. The wedge-shaped top electrode 624 can be formed of various process compatible materials, such as silicon. In some implementations, the wedge electrodes are shaped to be inserted into the cutout 622 to fill the cutout 622 .

Referring to FIG. 6D , a cross-sectional view of a part of the frame 620 along section line A is shown. In some implementations, the frame has an upper portion 625 , an inner sidewall 626 and an opening 627 .

In general, the respective lengths L of the plurality of coplanar filaments 610 are set to create a desired shape of the plasmonic region. Frame 620 may be shaped to provide support for coplanar filaments 610 . In some implementations, the ends of the coplanar filaments 610 are supported by the inner side walls 626 of the frame 620, similar to the configuration shown in Figure 6B. In some implementations, the ends of the coplanar filaments 610 are bent (eg, 90°) to be supported by the upper portion 625 of the frame 620, as shown in the electrode assembly 220a of FIG. 2B. In some implementations, the opening 627 of the frame 620 can determine the shape of the plasma region.

In some implementations, theta is close to 0, such as <20°. Referring to FIG. 6E , the assembly 601 has two wires, and the wires are arranged at θ=0°, ie, the wires are parallel to the bisector 605 . The frame 620 of the assembly 601 has cutouts 622 and wedge electrodes 624 . Wedge electrode 624 may be grounded. In such a configuration, the shape of the plasma field generated by electrode assembly 601 is influenced by the interaction between wire 610 and wedge electrode 624, thereby creating a wedge-shaped plasma field. In configurations where theta approaches 0°, the effect of plasma inhomogeneities parallel to the wire 610 may be reduced as the direction of travel of the workpiece 115 relative to the orientation of the wire 610 is substantially 90°.

7A-7D are conceptual schematic diagrams of various electrical configurations of wedge-shaped electrode assemblies. The wires of the electrode assembly can be electrically connected in various configurations. Referring to FIG. 7A , the electrode assembly 700 is similar to the electrode assembly 600 and has a first bus 730 and a second bus 740 . The first bus 730 and the second bus 740 may be located on opposite sides of the chamber body 102, such as outside the chamber.

The first bus 730 has a first end 750 and a second end 751 opposite to the first end 750 . The first bus 730 and the second bus 740 are electrically connected to respective opposite ends of the respective wires 710 of the electrode assembly 700 . Wire 710 is similar to wire 300 unless otherwise noted. Electrode assembly 700 can be driven in various ways using one or more RF power sources.

In some implementations, the first RF power source drives the first bus 730 and the second bus 740 is connected to RF ground. In such a configuration, RF current flows through the wire 710, and the electrode assembly can serve primarily as a source of ICP plasma.

In some implementations, the first RF power source drives the first bus 730 and the second bus 740 is electrically floating. In such a configuration, the electrode assembly can serve primarily as a source of CCP plasma. The RF current return path may be provided by the chamber body 102 , the upper electrode 108 , the wedge-shaped top electrode 624 , or the workpiece support electrode 116 .

In some implementations, a first RF power source drives the first bus 730 at a first terminal 750, a second RF power source drives the first bus 730 at a second terminal 751, and the second bus 740 is connected to RF ground. In such a configuration, the electrode assembly can serve primarily as a source of ICP plasma.

In some implementations, the first RF power source drives the first bus 730 and the second RF power source drives the second bus 740 .

In general, the RF drive point at which the RF power supply is connected to the bus is chosen to optimize the uniformity of the resulting plasma. For example, the drive point locations may be selected based on minimizing non-uniformity in RF signal amplitude experienced by individual wires 710 .

In some implementations, the electrode assembly within the chamber can include first and second sets of coplanar filaments. The filaments of the first and second groups may be arranged in an alternating pattern along a direction perpendicular to their longitudinal axes. In doing so, the coplanar filaments alternate between the first and second sets.

Referring to FIG. 7B , an electrode assembly 702 similar to electrode assembly 600 has a first set and a second set, the first set may include coplanar filaments 710 and 714 , and the second set includes coplanar filaments 712 . The first group is electrically connected to the first bus 732 and the second group is electrically connected to the second bus 742 . One end of each wire remote from the bus to which it is connected may be "floating" or grounded. If the ends of the filaments are floating, the two sets of filaments can be considered to form an interdigitated array.

The first bus 732 may have a first end 752 and a second end 753 opposite to the first end 752 . In some implementations, the first RF power supply drives the first bus 732 with the first RF signal, and the second RF power supply drives the second bus 742 with the second RF signal. The first and second RF signals may have the same frequency and stable phase relationship as each other. For example, the phase difference between the first RF signal and the second RF signal may be 0 degrees or 180 degrees. In some implementations, the phase relationship between the first and second RF signals provided by the RF power supply 422 can be adjustable between 0 and 360°. In some implementations, RF supply 422 may include two individual RF power supplies 422a and 422b that are phase locked to each other.

In some implementations, the first RF power supply drives the first bus 732 and the second bus 742 is connected to RF ground. In this case, the second bus 742 and the even array of wires connected to the second bus 742 may serve as an RF current return path.

In some implementations, a first RF power source drives the first bus 732 at a first terminal 752, and a second RF power source drives the first bus 732 at a second terminal 753, and the second bus 742 is connected to RF ground.

In some implementations, a first RF power source drives the first bus 732 and a second RF power source drives the second bus 742 . In this case, the electrode assembly 702 may serve primarily as a source of CCP plasma. The RF current return path may be provided by the chamber body 102 , the top electrode 108 , the wedge-shaped top electrode 624 , or the workpiece support electrode 116 .

Referring to FIG. 7C , an electrode assembly 704 similar to electrode assembly 600 has a single bus 734 . Bus 734 is electrically connected to both ends of wire 710 .

In some implementations, the first RF power source drives the first bus 734 . The first bus 734 can have a first end 754 and a second end 755, and in some implementations, a first RF power source drives the first bus 734 at the first end 754 and a second RF power source drives the second end 755. The first bus 734 . In such a configuration, the electrode assembly can serve primarily as a source of CCP plasma. The RF current return path may be provided by the chamber body 102 , the top electrode 108 , the wedge-shaped top electrode 624 , or the workpiece support electrode 116 .

Referring to FIG. 7D , an electrode assembly 706 similar to electrode assembly 600 has a first bus 736 and a second bus 746 . The first bus 736 and the second bus 746 are electrically connected to respective opposite ends of the wire 710 of the electrode assembly 706 . The first RF power source drives the first bus 736 at drive point 756 . The second bus 746 may be connected to RF ground.

The first RF signal generated by the first RF power supply can be attenuated by various sources of RF loss. For example, the RF transmission lines forming the bus 736 are lossy due to the finite conductivity of the conductors or due to a dielectric loss tangent due to the dielectric material forming the transmission lines. As another example, plasmonic loading of RF transmission lines affects RF losses. Accordingly, wires 710 connected at different locations along the direction of propagation of the RF signal may experience different RF signal amplitudes. For example, referring to FIG. 7A , an RF signal transmitted at first end 750 will attenuate as it propagates down the length of first bus 730 . As such, the amplitude of the RF signal at the wire 710 near the second end 751 will be less than the amplitude of the RF signal at the wire 710 near the first end 750 where the RF signal is being transmitted.

Standing waves generated by reflections of the RF signal due to imperfect RF impedance matching/termination may also create non-uniformities in RF signal amplitude along the length of the first bus 730 . For example, an RF signal transmitted at the first end 750 once reaching the second end 751 may be reflected back to the first end 750 due to the lack of an impedance matching termination, thereby creating a standing wave along the length of the first bus 730 .

Such non-uniformity in RF signal amplitude across the length of first bus 730 may cause plasma non-uniformity.

By using a recursive RF feed structure, the non-uniformity of the RF signal amplitude across the first bus 730 can be reduced. Referring back to FIG. 7D, the first bus 736 is configured to form a recursive RF feed structure to deliver the first RF signal generated by the first RF power source to the wires 710 such that, for all wires 710, from the drive point 756 to the respective wire The signal path length of 710 and the loss experienced by the RF signal are approximately equal. Such approximately equal path lengths may enable approximately equal RF signal amplitudes at the driven end (ie, the end connected to the first bus 736 ) of the wire 710 . In some implementations, RF signal amplitude non-uniformity is further mitigated by configuring the recursive RF feed structure such that each bracnch of the structure is connected to an approximately equal overall length of wire. For example, from left to right, 7, 6, 5, 4 wires are respectively connected to the individual branches of the recursive RF feed structure. This approximately equal overall length of each branch can help improve uniformity when the electrode assembly 706 is operating as an ICP source. In some implementations, each level of the feed structure is shielded back by a corresponding ground plane, and a corresponding level of vertical via connection structure penetrates the ground plane.

In cases where the electrode assembly is driven by two RF signal sources, various factors affect the shape of the resulting plasma region. Examples of factors include the frequency and phase relationship of the two RF signals. Referring to FIG. 7B, for example, when the frequencies of the first and second RF signals driving the first bus 732 and the second bus 742 are the same and the phase difference is set to 0 degrees (“unipolar” or “single-ended”), the electrical Slurry regions are pushed out of the gaps between coplanar filaments 710, resulting in discontinuities or inhomogeneities, eg, in some cases where the spacing between cylindrical shells is small. When the phase difference of the RF signals driving adjacent coplanar filaments 710 is set to 180 degrees (“differential”), the plasmonic region is more strongly confined between the coplanar filaments 710 . Any phase difference between 0 and 360 degrees can be used to affect the shape of the plasma region.

In general, the grounding of the workpiece support electrode 116 is a factor that affects the shape of the plasma region. The imperfect RF grounding of electrode 116 combined with the 0 degree phase difference between the RF signals driving adjacent coplanar filaments pushes the plasma region towards the top gap. However, if adjacent coplanar filaments (eg, coplanar filaments) are driven with RF signals having a 180 degree phase difference, the resulting plasma distribution is much less sensitive to imperfect RF grounding of the electrode 116 . Without being bound by any particular theory, this may be due to the RF current returning through adjacent electrodes due to the differential nature of the drive signal.

The electrical configuration and characteristics of the aforementioned electrode assemblies (eg, 400, 500, 502, 504, 600, 601, 700, 702, and 704) can be dynamically changed using RF switches coupled to various positions of the electrode assembly in various configurations.

Referring to FIG. 8A , an electrode assembly 800 includes a wire 810 , a first bus 820 and a second bus 824 . As shown, the buses 820 and 824 may have a respective third end 821 and a respective fourth end 822 . Wire 810 is similar to wires 610 and 300 unless otherwise noted. Each wire 810 has a respective first end 811 and a respective second end 812 . The first bus 820 and the second bus 824 can be located inside the chamber body 102, in the chamber ceiling, or outside the chamber, and can be between individual ends of the wire 810 and along the buses 820 and 824 (such as along the bus The lengths of 820 and 824) form electrical connections between the various locations.

The wire 810 can be divided into a first multiplicity 816 wire and a second multiplicity 817 wire. In some implementations, the filaments 810 of the first multiplicity 816 and the second multiplicity 817 can be arranged in an alternating pattern along a direction perpendicular to their longitudinal axes such that the coplanar filaments alternate between the first and second groups, as the picture shows.

A first end 811 of a wire of the first multiplicity 816 may be coupled to a first bus 820 . The first end 811 of the wire of the second multiplicity 817 may be coupled to the second bus 822 . The coupling between the wire 810 and the bus can be achieved using simple wires or metal strips (if the length is short relative to a fraction of the wavelength of the RF frequency), or by using RF transmission lines such as coaxial cables.

In some implementations, the electrode assembly 800 additionally includes a third bus 826 and a fourth bus 828 . In such an implementation, the second end 812 of the wire of the first multiplicity 816 can be coupled to the third bus 824 . The second end 812 of the wire of the second multiplicity 817 may be coupled to a fourth bus 826 .

Buses 820, 824, 826, and 828 are configured to be electrically coupled to the individual wires 810 to which they are coupled. The RF transmission lines forming the bus may have lengths comparable to or greater than a significant fraction of the wavelength of the RF frequency (eg >1/10 wavelength), and have losses, ie absorption of RF power, due to intentional plasmonic loading of the wire array. Accordingly, wires 810 connected at different locations along the direction of propagation of the RF signal may experience different RF signal amplitudes. For example, an RF signal transmitted at the third end 821 of the first bus 820 will attenuate as it propagates down the length of the first bus 820 . As such, the amplitude of the RF signal at the wire 810 near the second end 822 will be less than the amplitude of the RF signal at the wire 810 near the first end 821 where the RF signal is being transmitted. Such non-uniformity in RF signal amplitude across the length of the first bus 820 or 824 may cause plasma non-uniformity.

In general, the plasma region generated by the electrode assembly 800 may contain substantial inhomogeneities in plasma density over a substantial area. For example, for a plasma region of 40 cm long by 40 cm wide, a significant difference in plasma uniformity can be observed between RF signal frequencies of 13.56 MHz and 60 MHz. When driven at a lower frequency (eg, 13.56 MHz), the plasma density may decrease away from the ends 811 and 812 toward the central portion of the filament 810 . However, along the direction perpendicular to the longitudinal axis of the filament, the temporal average of the plasma density remains substantially spatially uniform. When driven at a higher frequency (eg 60 MHz), the plasma density becomes more non-uniform both along the filament and perpendicular to the longitudinal axis of the filament. For example, a periodic distribution of local maxima and minima can be formed along two directions. Without wishing to be bound by theory, this pattern of non-uniformity may be at least partially caused by the presence of standing waves.

This non-uniformity may be able to be mitigated by dynamically changing the electrical characteristics of the electrode assembly 800 using RF switches. It may also be possible to intentionally introduce inhomogeneity in the voltage signal to compensate for other sources of inhomogeneity in the workpiece, eg non-uniform layer thickness, or plasma density (eg non-uniform gas distribution).

Referring to FIG. 8B , switched electrode system 802 includes a first RF switch 830 , a second RF switch 834 , a third RF switch 836 , a fourth RF switch 838 , a first tap 840 and a second tap 842 . In general, the first and second taps 840 and 842 can be connected to various signals and potentials to generate the plasma, eg, to first and second RF signals, RF ground.

Each RF switch includes a first terminal 831 and a second terminal 832 . In general, the RF switch 830 operates bi-directionally, and the first and second terminals 831 and 832 are not tied to specific physical terminals of the RF switch, but are used to represent two different terminals of the RF switch. RF switches 830, 834, 836, and 838 may be provided using various RF switch components. Examples of RF switching components include mechanical relays or switches, PIN diodes, saturable inductors/reactors, MOSFETs, electronic circuits that include these components, and when combined with RF power generators with adjustable RF signal frequency Frequency-dependent impedance circuits.

In general, the first and second taps 840 and 842 may be positioned along respective lengths of the buses 820, 824, 826, and 828, eg, in the middle of the buses. In some implementations, the first tap 840 is located in the middle of the first bus 820 and the second tap 842 is located in the middle of the fourth bus 828 .

In some implementations, the first and second taps 840 and 842 are differentially driven by two RF signals having the same frequency (eg, 60 MHz) and having a relative phase difference of 180 degrees.

In general, the first and second terminals 831 and 832 of the RF switch can be coupled to the bus in various ways to achieve various effects. For example, respective first terminals of RF switches 830, 834, 836, and 838 are connected to terminals of buses 820, 824, 826, and 828, as shown. In such a configuration, closing of any of the RF switches 830, 834, 836, and 838 electrically connects or "shorts" the corresponding ends ("corners") of the bus. A short circuit at a corner may cause a change in the RF reflection coefficient at that location such that RF signal amplitude and power coupling at a localized region of wire 810 near the shorted corner is reduced, thereby reducing localized plasma generation. Shorting of the corners may also shift and/or change the spatial distribution of maxima and minima in the plasma density.

In general, electrical connections and couplings can be provided by wires, coaxial cables, waveguides, or by physical contact (eg, swaging, soldering, one-piece fabrication).

In general, process uniformity of workpieces can be improved by time averaging of plasma exposure. One way to achieve temporal averaging of plasma exposure is through the spatial distribution of inhomogeneities in the moving plasma region. For example, by turning on and off ("modulating") RF switches coupled to the four corners of the electrode assembly, the plasma density distribution (non-uniformity) can be shifted.

RF switches 830, 834, 836, and 838 can be modulated in various ways to achieve a desired time-averaged plasma density. An example of a procedure for modulating an RF switch is to cyclically connect pairs of points on different buses. For example, the system may operate as follows: (1) close RF switch 830 for a first duration and then open, (2) close RF switch 834 for a second duration and then open, (3) close RF switch 836 for a third duration , then turn on, (4) turn off the RF switch 838 for a fourth duration. The first through fourth durations may be determined based on a desired program repetition rate. For example, the repetition rate can be set to be much faster than the timescale of certain actions, such as device charging. For example, in a program with 4 states, the duration of each state including dead time can be set to 50 µs to achieve a repetition rate of 5 kHz.

In some implementations, dead time is inserted between steps of the procedure. Dead time provides a "break before make" contact to prevent shorting of two or more generators in certain configurations. In some implementations, the closing of the switches may overlap in time. For example, two switches can be modulated simultaneously, such as pairs of diagonal switches (830-838, 834-836), pairs of adjacent switches (830-834 and 836-838, 832-836 and 834-838) . As another example, all four switches can be turned on and off simultaneously.

Referring to Figure 8C, an example of a switched electrode system 804 is shown. Switched electrode system 804 is similar to system 802 unless otherwise noted. The switched electrode system 804 includes a first RF switch set 850 , a second RF switch set 854 , a third RF switch set 856 , and a fourth RF switch set 858 . The first RF switch group 850 includes subswitches 860a and 860b, the second RF switch group 854 includes subswitches 860c and 860d, the third RF switch group 836 includes subswitches 860e and 860f, and the fourth RF switch group 838 includes subswitches 860g. and 860h. The sub-switch is similar to RF switch 830 .

A first terminal 831 of the sub-switch is connected to terminals of the buses 820 , 824 , 826 and 828 . In some implementations, the second terminal 832 of the sub-switch is connected to RF ground. In such a configuration, closure of any one sub-switch electrically couples the respective end of the bus to RF ground or grounds the end of the bus. Grounding of the ends of the bus may reduce the RF signal amplitude in a localized region of the wire 810 near the RF ground end of the bus, and result in a reduced magnitude of the electric field or lower power coupling in that region. A reduction in the magnitude of the electric field may result in reduced plasma generation in this region.

The bank of RF switches and individual sub-switches can be modulated in various ways to provide modulation of the plasma density distribution. For example, each RF switch bank may operate as a single unit, wherein the sub-switches of the RF switch bank are turned on and off as a single unit. As another example, the sub-switches of each RF switch bank can be turned on and off independently.

The switches may be modulated in various different programs in a manner similar to the various programs described with respect to FIG. 8B. For example, a switched electrode system can be operated by cyclically closing one switch group at a time (optionally with a time delay), cyclically closing switch groups at times when different groups are off, alternating switch groups, or simultaneously switching on and turn off all switches.

As another example, the system may operate as follows: (1) turn off the first and third RF switch sets 850 and 856 for a first duration and then turn on, (2) turn on all switches, (3) turn off the second and fourth RF Switch sets 854 and 858 are turned on for a second duration and then on.

As yet another example, the system may operate as follows: (1) close the first switch group 850 for a first duration and then turn on, (2) close the second switch group 854 for a second duration and then turn on, (3) close the third Switch group 856 is on for a third duration and then on, (4) fourth switch group 858 is off for a fourth duration and then on, (5) all switch groups are on, (6) all switch groups are off.

In some implementations, RF switches can be used to dynamically reconfigure the feeding of RF signals to various locations on the bus. Referring to Figure 8D, an example of a switched electrode system 806 is shown. Unless otherwise noted, switched electrode system 806 is similar to system 804 and can operate in a similar manner.

The first multiplex 816 is driven with an RF signal at taps 844 and 846 . The RF signals driving taps 844 and 846 may be the same frequency or different frequencies. The phase relationship of the two signals can be 0, 180, or any value between 0 and 360 for the case of the same frequency. For some implementations, the phase relationship can be modulated over time. Second terminals 832 of sub-switches 860a, 860c, 860f and 860h are connected to respective taps 844 and 846 as shown.

In such a configuration, the ground characteristics of the second multiplex 817 can be modulated using corresponding sub-switches, and RF signals can be transmitted to the buses 820 and 826 from different locations (eg, from terminals 821 and 822 ). A combination of grounding characteristics and modulation of the RF signal distribution can be used to modulate plasma density to improve process uniformity by time averaging.

In such a configuration, it may be advantageous to maintain at least one of the sub-switches 860 in a closed state to provide a continuous supply of RF signals to the assembly 800 .

Referring to Figure 8E, an example of a switched electrode system 808 is shown. Unless otherwise noted, switched electrode system 808 is similar to system 804 and may operate in a similar manner. The second terminal 832 of the sub-switch is connected to a single tap 848 . A symmetrical distribution network as shown can be used to improve the uniformity of the RF signal delivered to the four corners of the system 808 . The sub-switches can be modulated in various ways previously described to change plasma distribution and improve process uniformity.

In some implementations, switches can be distributed across the bus to allow finer control of the instantaneous plasma uniformity, thereby improving time-averaged plasma uniformity. Referring to Figure 8F, an example of a switched electrode system 801 is shown. Unless otherwise noted, switched electrode system 801 is similar to system 808 and may operate in a similar manner. The first bus 820 is coupled to a first RF switch group 870, such as three or more sub-switches. Each RF switch bank includes a plurality of sub-switches 860 . The first terminals of the sub-switches 860 of the first RF switch bank 870 are electrically coupled to the first bus at various locations across the length of the first bus 820 . In some implementations, the coupling points are approximately equally spaced, as shown. A second terminal of the sub-switch 860 of the first RF switch bank 870 is electrically coupled to the tap 848 to receive an RF signal.

The second, third, and fourth buses 824, 826, and 828 are connected to second, third, and fourth RF switch banks 874, 876, and 878, respectively, each in a manner similar to that of the first bus 820 and the first RF switch bank. 870 way to connect.

In such a configuration, the additional level of control over where the RF signals are transmitted along the length of the bus can result in improved time-averaged plasma uniformity.

In general, the number of sub-switches included in an RF switch bank can be determined based on, for example, the length of the bus, the size of the plasma region, the frequency and power of the RF signal, and the chamber pressure.

In some implementations, an RF switch can be used to dynamically reconfigure the RF signal feed and ground locations to provide a mode-selectable plasma source that can be switched between a primary CCP mode and a primary ICP mode . Referring to Figure 9A, an example of a switched electrode system 900 is shown. Unless otherwise noted, switched electrode system 900 is similar to system 802 and may operate in a similar manner. The first terminals 831 of the RF switches 830 and 834 are connected to the corresponding third terminal 821 and the fourth terminal 822 of the second bus 824, and the first terminals 831 of the RF switches 836 and 838 are connected to the corresponding third terminals of the third bus 826 821 and the fourth end 822, as shown in the figure. The second terminal 832 is connected to RF ground.

RF switches 830 , 834 , 836 , and 838 can be controlled in various ways to change the dominant mode of plasma generation by switched electrode assembly 900 . For example, by closing all four RF switches, RF current flows along the length of the wire 810, creating a magnetic field and generating a predominantly inductively coupled plasma. By turning on all four switches, the RF current is reduced and the assembly 900 generates a predominantly capacitively coupled plasma.

In some implementations, the first and second RF signals driving the respective taps 840 and 842 are 180 degrees out of phase, ie, driven differentially. In this case, alternating wires 810 belonging to the first and second multiplexes 816 and 817 are fed from opposite ends of RF signals having a phase difference of about 180 degrees, resulting in the generation of an auxiliary RF magnetic field. In some implementations, the first and second RF signals driving the respective taps 840 and 842 have a phase difference of about 0 degrees. In this case, alternating wires 810 belonging to the first and second multiplexes 816 and 817 are fed from opposite ends of the RF signal with a phase difference of about 0 degrees, resulting in opposite RF magnetic fields.

In some implementations, switches can be distributed across the bus to allow finer control of instantaneous plasma uniformity, thereby improving time-averaged plasma uniformity. Referring to Figure 9B, an example of a switched electrode assembly 902 is shown. Switched electrode assembly 902 is similar to system 801 unless otherwise noted. The first bus 820 is coupled to a first RF switch group 870 including a plurality of sub-switches 860 .

The first terminals of the sub-switches 860 of the first RF switch bank 870 are electrically coupled to the first bus at various locations across the length of the first bus 820 . In some implementations, the coupling points are approximately equally spaced, as shown. The second terminal of the sub-switch 860 of the first RF switch group 870 is electrically coupled to the tap 940 to receive the first RF signal.

The second bus is connected to the second RF switch group 874 at the first terminal of the sub-switch, and the second terminal of the sub-switch is connected to RF ground.

The third bus is connected at the first terminal of the sub-switch 860 to the third RF switch group 876, and the second terminal 832 of the sub-switch 860 of the third RF switch group 876 is connected to RF ground.

The fourth bus is connected to the fourth RF switch bank 878 at the first terminal of the sub-switch, and the second terminal of the sub-switch is electrically coupled to the tap 942 to receive the second RF signal.

The first and second RF signals driving taps 940 and 942 may be at the same frequency or different frequencies. The phase relationship of the two signals can be 0, 180, or any value between 0 and 360 for the case of the same frequency. For some implementations, the phase relationship can be modulated over time.

The RF switch sets 870 , 874 , 876 and 878 can be controlled in various ways to change the primary mode of plasma generation by the switched electrode assembly 902 . For example, by closing at least one sub-switch from each of the first set 870 and the fourth set 878, and turning on the second and third RF switch sets 874 and 876, the assembly 902 generates a predominantly capacitively coupled plasma.

As another example, the component 902 generates the main Inductively coupled plasma. In some implementations, the first and second RF signals driving the respective taps 940 and 942 are 180 degrees out of phase, ie, driven differentially. In this case, alternating wires 810 belonging to the first and second multiplexes 816 and 817 are fed from opposite ends of RF signals having a phase difference of about 180 degrees, resulting in the generation of an auxiliary RF magnetic field. In some implementations, the first and second RF signals driving respective taps 940 and 942 have a phase difference of about 0 degrees. In this case, alternating wires 810 belonging to the first and second multiplexes 816 and 817 are fed from opposite ends of the RF signal with a phase difference of about 0 degrees, resulting in opposite RF magnetic fields.

In some processing applications, ICP using opposing RF magnetic fields that can deposit RF power into the plasma in ribbons roughly parallel to the filaments can provide a more uniform plasma, especially when the workpiece is close to the plasma source (such as electrode assembly), that is, a small bottom gap 132 . Therefore, it may be beneficial to have the ability to change the phase relationship of the first and second RF signals.

In general, individual sub-switches of the first and fourth groups 870 and 878 can be modulated to change the plasma density distribution. Additionally, where the switched electrode assembly 902 is configured to generate primarily inductively coupled plasma, the sub-switches of the second and third sets 874 and 876 can be individually modulated to further alter the plasma density distribution.

In general, while the digital display bus is driven near the center and ends floating or with ground terminations, depending on the application, RF configuration, frequency, and region of operation (plasma loading), there are end or center) may be advantageous to be driven or terminated.

In general, where the second terminal of the RF switch is connected to RF ground, a variable impedance can be placed in series to RF ground to provide a variable RF termination impedance for further control over changes in plasma density.

In general, although the illustrations show taps connected to the center of the respective bus, the taps for applying RF power to the electrode assembly may be located at one or more ends, center, or other locations on the bus.

A switch can be used to improve the time-averaged plasma uniformity of the wedge-shaped electrode assembly. Referring to Figure 10, an example of a switched electrode assembly 1000 is shown. Switched electrode assembly 1000 includes a wedge-shaped electrode assembly 1010 . Wedge electrode assembly 1010 is similar to wedge electrode assembly 704 unless otherwise noted. Assembly 1010 includes a wedge-shaped top electrode 624, which may be grounded. The switched electrode assembly 1000 includes a first RF switch 1030 , a second RF switch 1034 , a third RF switch 1036 , a fourth RF switch 1038 and a tap 1040 . The RF switch is similar to RF switch 830 . First terminals of RF switches 1030 and 1034 are connected to first terminal 754 of assembly 1010 , and first terminals of RF switches 1036 and 1038 are connected to second terminal 755 of assembly 1010 . The second terminals of the first and fourth RF switches 1030 and 1038 are connected to each other and to the tap 1040, and the second terminals of the second and third RF switches 1034 and 1036 are connected to RF ground.

First and fourth RF switches 1030 and 1038 may be turned on and off to selectively feed an RF signal to first end 754 , second end 755 , or both of assembly 1010 . The second and third RF switches 1034 and 1036 can be turned on and off to selectively ground the first end 754 or the second end 755 of the assembly 1010 .

The RF switch can be modulated in various ways to improve time-averaged plasma uniformity. The following is an example of a procedure: (1) close RF switch 1030 for a first duration, and open switches 1034, 1036, and 1038 (eg, for 30 microseconds), (2) close 1030, 1036, open 1034, 1038 (eg, for 40 microseconds), then (3) turn off 1036 and turn on 1030, 1034 and 1036 (for example up to 30 microseconds). Optionally, the unpowered terminal may be grounded after a short delay after the RF signal is applied to the other terminal, and the grounded terminal may be ungrounded before the RF signal is applied to the terminal.

Here is another example of the program: (1) 1030=ON, 1038, 1034, 1036=OFF for 30 microseconds, (2) 1030, 1038=ON, 1034, 1036=OFF for 40 microseconds, (3) 1038 =ON, 1034, 1030, 1036=OFF for 30 microseconds, and then repeat the cycle several times until the process step is completed or the cycle is reversed alternately. Optionally, the unpowered terminal may be grounded after a short delay after power is applied to the other terminal, and the grounded terminal may be ungrounded before power is applied to that terminal.

In general, the wedge-shaped electrode assembly 1010 can resemble an electrode. In general, switches can be applied to other electrode assemblies, such as 600, 601, 700, 702, 704.

Various circuit implementations may be used to provide an RF switch suitable for switching RF signals for plasma generation. There are various considerations in order to implement an RF switch (eg, RF switch 830, sub-switch 860) to be used in a switched electrode system. Examples of these considerations include RF power handling capability, switching speed, ON-state impedance, OFF-state impedance, and bidirectionality.

In general, a switch is said to be in the "ON" or closed state when the impedance presented between the two terminals of the switch is low, and in the "OFF" state when the impedance is high. )” or open circuit (open) state.

A PIN diode switch can be used to provide a suitable RF switch. Referring to FIG. 11A , a PIN diode switch 1100 includes a PIN diode 1110 , a first capacitor 1120 having a capacitance C1 , a second capacitor 1122 having a capacitance C2 , and an inductor 1140 having an inductance L1 . The switch 1100 has a first terminal 1131 , a second terminal 1132 and a control terminal 1134 . The first terminal 1131 may provide the first terminal 831 and the second terminal 1132 may provide the second terminal 832 of the RF switch 830 .

The first capacitor 1120 and the inductor 1150 may be connected in parallel between the first terminal 1131 and the second capacitor 1122 . Next, the PIN diode 1110 may be connected between the first terminal 1131 and the second terminal 1132 in parallel with the first capacitor 1120 , the inductor 1150 and the second capacitor 1122 . The control terminal 1134 may be connected between the second capacitor sum 1122 and the first capacitor 1120 .

PIN diode 1110 is a diode with a wide undoped intrinsic semiconductor region between the p-type semiconductor and n-type semiconductor regions, and can be well suited for fast switching of high power RF signals. A PIN diode has an anode (+) and a cathode (-), and when a forward bias is established between the anode and cathode (eg > 0.7 V and/or diode current > 100mA), it can provide for RF A low-impedance conduction path for signals, such as <1 ohm.

The PIN diode switch 1100 operates based on the following working principle. The impedance of the PIN diode 1110 can be controlled by providing a control signal to the control terminal 1134 . The control signal is a quasi static voltage switched between a first level (eg 0.7V) and a second level (eg -2kV). Due to the quasi-static nature of the control signal, the control voltage and any resulting diode current can be conducted through the inductor 1140 . Additionally, the second capacitor 1122 blocks the control voltage from reaching the cathode. By providing a sufficiently large negative control voltage (eg -2kV) to the anode relative to the cathode, the PIN diode 1110 can be set to an "OFF" state, presenting a high impedance between its cathode and anode. When a sufficiently large positive control voltage (eg, 0.7V) is applied, PIN diode 1110 can be set to an "ON" state, presenting a low impedance path (eg, <1 ohm) for RF signals between terminals 1131 and 1132 . .

決定的諧振頻率。在諧振頻率f₀ 下，諧振器1150呈現接近開路（open circuit，如＞1000歐姆）的高阻抗，這取決於諧振器的品質因數。藉由選擇C1和L1的值使得諧振頻率與終端1131或1132處存在的RF信號的頻率對準（align），可以防止RF信號通過諧振器1150。A first capacitor 1120 and an inductor 1140 connected in parallel as shown form a parallel LC resonator 1150 . Resonator 1150 has the equation given by

Determine the resonant frequency. At the resonant frequency f ₀ , the resonator 1150 presents a high impedance close to an open circuit (eg, >1000 ohms), which depends on the quality factor of the resonator. By choosing the values of C1 and L1 such that the resonant frequency aligns with the frequency of the RF signal present at terminal 1131 or 1132 , RF signals can be prevented from passing through resonator 1150 .

In general, the capacitance C2 of the second capacitor 1122 can be set to provide a low impedance path at the frequency of the RF signal.

In some implementations, first capacitor 1120 is a variable capacitor ("capacitor") with an adjustable capacitance C1 that can be changed to optimize the resonance of the parallel LC circuit formed by first capacitor 1120 and inductor 1140 to match Frequency alignment of RF signals.

In some implementations, a control signal buffer amplifier 1136 may be provided to buffer and/or amplify the control signal applied at the control terminal 1134 to the anode of the PIN diode 1110 .

In general, multiple PIN diode switches can be used in combination to achieve a range of impedance values between the first and second terminals 1131 and 1132 . The control signal can also be set between the first and second levels to provide variable impedance.

In some implementations, the first terminal 1131 is connected to a bus (eg, bus 820 ), and the second terminal 1132 is connected to RF ground, forming a path to RF ground. In some implementations, the first terminal 1132 is connected to a first bus (such as bus 820) and the second terminal 1132 is connected to a second bus (such as bus 824), in which case the switch may be considered "floating," The potential of the second terminal 1132 is defined by external factors.

As another example, a saturable inductor switch can be used to provide a suitable RF switch. Referring to FIG. 11B , the saturable inductor switch 1102 includes a saturable inductor 1160 , a first capacitor 1124 having a capacitance C1 , and a second capacitor 1126 having a capacitance C2 . The switch 1102 has a first terminal 1131 , a second terminal 1132 and a control terminal 1135 . The first terminal 1131 may provide the first terminal 831 , and the second terminal 1132 may provide the second terminal 832 .

The saturable inductor 1160 has a primary winding 1162 with an inductance L1 and a control winding 1164 with an inductance L2. In some literatures, saturable inductors may also be referred to as saturable inductors or magnetic amplifiers. A saturable inductor is an inductor having a magnetic core that can be intentionally saturated by passing current through the control winding 1164 . Once saturated, the inductance L1 of the primary winding 1162 will drop significantly. The reduced inductance of the primary winding reduces the impedance of the RF signal, which can be used to implement a switch.

Primary winding 1162 of inductor 1160 may be connected in series with second capacitor 1126 , and first capacitor 1124 may be connected in parallel with primary winding 1162 and second capacitor 1126 between first terminal 1131 and second terminal 1132 . Control terminal 1135 is connected to control winding 1164, which may in turn be connected to ground.

The saturable inductor switch 1102 operates based on the following operating principle. First capacitor 1124 in parallel with the series combination of primary winding 1162 and second capacitor 1126 forms a parallel LC resonator that operates similarly to LC resonator 1150 . For example, the values of C1, C2, and L1 can be set so that when the control signal is set to the "OFF" or low state, the resonance of the switch 1102 occurs at the RF signal frequency (such as 60MHz), and in the "OFF" or low state there is no Current flows through the control winding 1164 . In this state, the switch 1102 is in an "open" state, presenting a high impedance between the first and second terminals 1131 and 1132 . When the control signal applied to the control terminal 1135 is set to "ON" or high state, the magnetic field generated by the current flowing through the secondary winding 1164 saturates the magnetic core of the saturable inductor 1160, thereby reducing the primary winding 1162 Inductor L1. The reduction in inductance L1 changes the resonant frequency of the switch 1102, presenting a low impedance between the first and second terminals 1131 and 1132 at the same RF signal frequency. This low impedance state can be used as a closed circuit state for switch 1102 .

In some implementations, a control signal buffer amplifier 1137 may be provided to amplify and/or buffer the control signal applied at the control terminal 1135 so that a current sufficient to saturate the saturable inductor 1160 may be applied to the control winding 1164 .

In some implementations, a low pass filter 1138 may be provided between the control signal terminal 1135 and the control winding 1164 to mitigate noise coupling from the control signal and/or RF signal propagating to the control signal terminal.

In general, by adjusting the control signal to provide a range of currents to the control winding 1164, the switch presented between the first terminal 1131 and the second terminal 1132 can be controlled between an "ON" state and an "OFF" state. impedance.

In some implementations, the first terminal 1131 is connected to a bus (eg, bus 820 ), and the second terminal 1132 is connected to RF ground. In some implementations, the first terminal is connected to a first bus (eg, bus 820 ) and the second terminal 1132 is connected to a second bus (eg, bus 824 ).

The impedance presented by the aforementioned switches 1100 and 1102 and their switching states are controlled by the application of control signals. However, in some implementations, the characteristics of the switch may remain static, and instead the frequency of the RF signal may be modulated such that the switch presents an "open circuit" or "closed circuit" state to RF signals having different frequencies. For example, the frequency-dependent impedance of the circuit can be used to provide such frequency-based switching.

Referring to FIG. 12A , a frequency-based switch 1200 includes a first capacitor 1220 having a capacitance C1 , a second capacitor 1222 having a capacitance C2 , a first inductor 1240 having an inductance L1 , and a second inductor 1242 having an inductance L2 . The switch 1200 has a first terminal 1231 and a second terminal 1232 .

The first capacitor 1220 and the first inductor 1240 may be connected in series, and the second capacitor 1222 and the second inductor 1242 may be connected in series. The pair of circuits may be connected in parallel between the first terminal 1231 and the second terminal 1232 .

The combination of L1, C1, L2 and C2 can be set such that at a first frequency (eg 58MHz) a low impedance (eg <0.1 ohm) is presented between the first and second terminals 1231 and 1232, and at a second frequency (such as 62MHz), showing high impedance (such as> 100 ohms). For example, the following values of L1=L2=0.1μH, C1=75.3pF, C2=58.6pF can provide low impedance resonance at 58MHz and high impedance resonance at 62MHz.

Without wishing to be bound by theory, a low impedance resonance can be provided by a series LC resonance and a high impedance resonance can be provided by a parallel LC resonance.

Capacitance and inductance can be arranged to form frequency-based switches with approximately complementary responses to the examples provided above. For example, the following values L1 = L2 = 0.1 μH, C1 = 65.9 pF, C2 = 87.8 pF can provide a low impedance resonance at 62 MHz and a high impedance resonance at 58 MHz, appearing approximately complementary or opposite with respect to the first example response. This complementary behavior can be used to form various frequency-switched electrode systems.

In some implementations, discrete capacitors and inductors may be implemented with distributed circuit elements (eg, transmission line segments, stubs).

Referring to FIG. 12B , a frequency-switched electrode system 1202 includes an electrode assembly 800 , a first frequency-based switch 1200 a , a second frequency-based switch 1200 b , and a tap 1260 . RF signals of different frequencies may be provided to the tap 1260, for example, using a variable frequency RF generator with a matching network and isolators or circulators in series.

In this configuration, the frequency of the RF signal supplied through tap 1260 may be alternated from a first frequency to a second frequency such that more of the RF signal is coupled to the left side of electrode assembly 800 through switch 1200a, or through switch 1200b. Coupled to the right side of the electrode assembly 800 . Alternatively, the frequency of the RF signal provided through tap 1260 may be driven to vary between a first frequency and a second frequency, such as with a ramp function.

For example, by setting the component values as L1a=L2a=0.1 μH, C1a=75.3pF, C2a=58.6pF, the first switch 1200a can provide low impedance resonance at 58MHz and high impedance resonance at 62MHz. The component values of the second switch 1200b can be set as L1=L2=0.1 μH, C1=65.9pF, C2=87.8pF to provide low impedance resonance at 62MHz and high impedance resonance at 58MHz. In such a configuration, by switching the frequency of the RF signal to the first frequency (such as 58MHz), most of the RF signal can be coupled to the left side of the electrode assembly 800 through the first switch 1200a, and by switching the frequency of the RF signal to Switching to the second frequency (eg, 62MHz), most of the RF signal can be coupled to the right side of the component 800 through the second switch 1200b. When the frequency is midway between the two frequencies, roughly around 60MHz, then power is roughly similarly coupled at both ends, and high center non-uniformity may result.

In some implementations, transmission line segments may be used to vary the frequency-dependent impedance of switch 1200 . For example, to account for the velocity factor of the transmission line, quarter wavelength length transmission line segments may be used to connect the corners of the electrode assembly 800 to the terminals of the switches 1200a and 1200b. By using a quarter wavelength transmission line, the impedances presented at the first and second frequencies can be swapped. For example, the low impedance of series resonance can be converted to a high impedance of about 1000 ohms, and the high impedance of parallel resonance can be converted to a low impedance of about 1 ohm.

In some implementations, the frequency-based switch 1200 can be used as a frequency-selective termination to provide impedance-matched termination at different frequencies to control the coupling of RF signals into the electrode assembly. Referring to FIG. 12C , a frequency-switched electrode system 1204 includes an electrode assembly 800 , a first frequency-selective terminal 1250 a , a second frequency-selective terminal 1250 b , and a tap 1260 . Unless otherwise stated, frequency selective terminals 1250a and 1250b may be provided by frequency-based switch 1200, and operate in a similar manner.

In some implementations, the component values of frequency selective terminals 1250a and 1250b can be set such that at a first frequency, terminal 1250a presents a characteristic impedance of an RF generator and transmission line, while terminal 1250b presents a high impedance. In such a configuration, termination 1250a provides an impedance-matched termination to RF ground, minimizing RF signal reflections and RF signal coupling to the left side of electrode assembly 800 . At the same time, the high impedance presented by terminal 1200b allows RF signals to be coupled to the right side of electrode assembly 800 .

In some implementations, the component values of frequency selective terminals 1250a and 1250b can be set such that at a first frequency, terminal 1250a presents a low impedance path to RF ground, while terminal 1250b presents a high impedance. In such a configuration, the low impedance path provided by terminal 1250a to RF ground minimizes RF signal coupling to the left side of electrode assembly 800 . At the same time, the high impedance presented by terminal 1200b allows RF signals to be coupled to the right side of electrode assembly 800 .

In general, frequency-based switches and frequency-selective terminations can be coupled to various locations along the bus. For example, an additional pair of coupling points to taps may be provided at approximately the center of the bus, and additional switches or terminals may be provided at those coupling points.

In general, frequency switching is not limited to 2 states corresponding to a high impedance state and a low impedance state, but may advantageously operate continuously between or outside the first and second switching frequencies.

In general, various combinations of frequency-based switches with various resonant frequencies can be used to extend frequency-based switching to 3, 4 or more frequencies.

In some plasma chambers, the workpiece is moved through the plasma processing region on, for example, a linear or rotating workpiece support. In such a chamber, the moving workpiece support may be DC grounded through, for example, a rotating mercury coupler, brushes or slip rings. However, a moving workpiece support may not be adequately grounded at radio frequencies. The RF ground path should have a much lower impedance than the plasma to make it an adequate RF ground. Lack of adequate RF ground paths can make it difficult to control ion energy at the workpiece and reduce process repeatability.

Therefore, there is a need for a plasma source that can efficiently generate a uniform plasma with desired properties (plasma density, electron temperature, ion energy, dissociation, etc.) resistance (such as pressure, power, gas composition); it has stable and repeatable electrical performance even when the workpiece moves; and it does not generate excessive metal contamination or particles.

Fig. 13 is a schematic side view of another example of a plasma reactor. The plasma reactor 2100 has a chamber body 2102 enclosing an inner space serving as a plasma chamber. The chamber body 2102 may have one or more side walls 2102a, a top plate 2102b, and a bottom plate 2102c. The interior volume 2104 may be cylindrical, such as for processing round semiconductor wafers. The plasma reactor includes a top electrode array assembly 2106 located at the top of the plasma reactor 2100 . The top electrode array assembly 2106 may adjoin the top plate (as shown in FIG. 13 ), or be suspended within the interior space 2104 and spaced from the top plate, or form part of the top plate. Portions of the sidewalls and floor of the chamber body 2102 may be grounded separately.

A gas distributor is located near the ceiling of the plasma reactor 2100. The gas distributor may include one or more ports 2110 in the sidewall 2102 that connect to a process gas supply 2112 . Alternatively or alternatively, the gas distributor may be integrated with the top electrode assembly 2106 as a single component. For example, passages to process gas supply 2112 may be formed through dielectric plates in assembly 2112 to provide openings in the ceiling of the plasma chamber. The gas supply 2112 delivers one or more process gases to the gas distributor 2110, the composition of which may depend on the process to be performed, such as deposition or etching.

A vacuum pump 2113 is connected to the interior space 2104 to evacuate the plasma reactor. For some processes, the chamber operates in the Torr range, and gas distributors supply argon, nitrogen, oxygen, and/or other gases.

Depending on the chamber configuration and the process gases supplied, the plasma reactor 100 may provide an ALD device, an etching device, a plasma processing device, a plasma enhanced chemical vapor deposition device, a plasma doping device, or a plasma surface cleaning device.

The plasma reactor 2100 includes a workpiece support 2114 , such as a pedestal, for supporting a workpiece with a top surface exposed to the plasma formed in the chamber 2104 . The workpiece support 2114 has a workpiece support surface 2114a facing the top electrode 2108 . In some implementations, the workpiece support 2114 includes a workpiece support electrode 2116 located inside the support 2114 , and a workpiece bias voltage supply 2118 is connected to the workpiece support electrode 2116 . A voltage supply 2118 may apply a voltage to clamp the workpiece 2115 to the support 2114 and/or supply a bias voltage to control properties of the generated plasma, including ion energy. In some implementations, the RF bias power generator 2142 is AC coupled to the workpiece support electrode 2116 of the workpiece support 2114 through an impedance match 2144 .

Additionally, the support 2114 may have internal channels 2119 for heating or cooling the workpiece 2115, and/or embedded resistive heaters (2119).

Electrode assembly 2106 is positioned at the ceiling of chamber 2104 . The electrode assembly 2106 includes a plurality of conductors 2120 extending laterally over the workpiece support 2114 . The conductors 2120 are coplanar at least in the region above the intended location of the workpiece on the support 2114 . For example, in this region the conductors may extend parallel to the support surface 2114a. The plurality of conductors 2120 may be arranged in an array of parallel lines. In some implementations, the conductors may have a “U shape” with both ends connected to corresponding busses on the same side of the chamber 2104 . Alternatively, the conductors may be arranged in an interlaced helix (an interleaved circular helix or an interleaved rectangular helix). The longitudinal axis of conductor 2120 may be disposed at a non-zero angle (eg, an angle greater than 20 degrees) to the direction of motion of workpiece 10 beneath electrode assembly 2106 . For example, the longitudinal axis of conductor 2120 may be substantially perpendicular to the direction of motion of workpiece 10 .

A gap 2132 is formed between the workpiece support 2114 and the electrode assembly 2106 . For high pressure (eg, 1-10 Torr), the gap 2132 may be 2-25mm. Fixing the workpiece may require a larger minimum clearance, for example about 5 mm, depending on the electrode-to-electrode spacing on the source and the thickness of the dielectric cover. At lower pressures (eg, less than 100 mTorr), the gap 2132 may be 1 cm to 50 cm.

In some implementations, the fluid supply 2146 circulates fluid through the electrode assembly 2106 . In some implementations, a heat exchanger 2148 is coupled to the fluid supply 2146 to remove heat or supply heat to the fluid.

The electrode assembly 2106 is powered by an RF power source 2122 . The RF power source 2122 may apply power to the conductor 2120 of the electrode assembly 2106 at a frequency such as 1 to 300 MHz. For some processes, the RF power supply 2122 provides greater than 2kW of total RF power at a frequency of 60MHz.

In some implementations, a heat sink 2150 , such as an aluminum plate, is attached to the top plate 2102b of the chamber body 2102 . A channel 2152 may be formed through the heat sink 2150 , and coolant may circulate through the channel 2152 . A heat exchanger 2154 may be connected to channel 152 to remove heat or supply heat to the coolant.

14A-14C are schematic diagrams of another example of a plasma reactor. In this example, the multi-chamber processing tool 200 includes the plasma reactor 100 in operation as in FIG. 13 unless otherwise noted.

The treatment tool 2200 has a body 2202 enclosing an interior space 2204 . The body 2102 may have one or more side walls 2202a, a top panel 2202b, and a bottom panel 2202c. Inner space 2204 may be cylindrical.

The processing tool 2200 includes a workpiece support 2214 (eg, a base) for supporting one or more workpieces 10 (eg, a plurality of workpieces). The workpiece support 2214 has a workpiece support surface 2214a. The workpiece support 2214 may include a workpiece support electrode 2116 , and a workpiece bias voltage source 2118 may be connected to the workpiece support electrode 2116 .

The space between the top of the workpiece support 2214 and the top plate 2202b may be divided by barriers 2270 into a plurality of chambers 2204a-2204d. The barrier 2270 may extend radially from the center of the workpiece support 2214 . Although four chambers are shown, there may be two, three or more than four chambers.

The workpiece may be rotated about axis 2260 by motor 2262 . As such, any workpiece 10 on the workpiece support 2214 will be sequentially carried through the chambers 2204a-2204d.

Chambers 2204a-2204d may be at least partially isolated from each other by pump-purge system 2280. The pump-purge system 2280 may include a plurality of channels formed through the barrier 2210, which allow a purge gas (e.g., an inert gas, such as argon) to flow into the space between adjacent chambers, and/or flow gas from adjacent chambers. The space between the chambers is pumped out. For example, pump-purge system 2280 may include first passage 2282 through which purge gas is forced into space 2202 between barrier 2272 and workpiece support 2214 , such as by a pump. Either side of the first channel 2282 (relative to the direction of motion of the workpiece support 2214) may be flanked by a second channel 2284 and a third channel 2286, which are connected to a pump to draw gas (including purge gas and any gas from an adjacent chamber (such as chamber 2204a)). Each channel may be an elongated slot extending generally radially.

At least one of chambers 2204 a - 2204 provides a plasma chamber of plasma reactor 2100 . The plasma reactor includes a top electrode array assembly 2106 and an RF power supply 2122, and may also include a fluid supply 2146 and/or a heat exchanger. Process gases may be supplied through ports 2210 positioned along one or both barriers 2270 to chamber 2104 . In some implementations, the port 2210 is positioned only on the front side of the chamber 2104 (relative to the direction of motion of the workpiece support 2214). Alternatively, process gas may be supplied through ports in the sidewall 2202 a of the tool body 2202 .

An example of an electrode assembly 2106 is shown in FIG. 15A . The electrode assembly 2106 includes a dielectric top plate 2130 , a plurality of conductors 2120 and a dielectric bottom plate 2132 . As described above, the conductors 2120 may be arranged as parallel linear strips that extend laterally over the workpiece support 2114 . The dielectric top plate 2130 may be a ceramic material.

The dielectric backplane 2132 provides a window for RF power, ie, is substantially transparent to RF radiation at the frequency used to generate the plasma. For example, base plate 2132 may be quartz or silicon nitride. The base plate protects the plasma process and workpiece environment from metal contamination or particle formation that might otherwise occur if conductors or ceramics are exposed to the plasma. Base plate 2132 may be a consumable component that is replaced periodically. The bottom plate can be relatively thin, such as 0.25mm-2mm, for example 0.5mm.

The conductors may have a width of 1-5 mm, and the interval W between the conductors 120 may be 0.5 to 3 mm. The conductors may be wider than the spacing, such as about twice as wide.

The thickness T of the lower dielectric plate 2132 should be less than twice the interval W between the conductors 2120, eg, less than the interval W between the conductors. At higher pressures, the gap between the lower dielectric plate 2132 and the upper dielectric plate 2130 should be "small", such as less than 0.5mm, eg less than 0.25mm, to avoid plasma behind the plates.

Conductor 2120 may be formed directly on the lower surface of dielectric top plate surface 2130 . For example, conductor 2120 may be formed by depositing (eg, plating, sputtering, or CVD) a thin layer across the bottom surface and then patterning by etching to form a stripline structure. The conductors may then be covered by a dielectric bottom dielectric plate 2132 .

Conductor 2120 may also be embedded (ie, buried) below the surface of the dielectric top plate. For example, the top plate 2130 may be a ceramic structure similar in structure to an electrostatic wafer chuck. For buried conductors, the dielectric bottom plate becomes optional, but can still be used as a dielectric cover (such as made of quartz) to protect the bottom surface of the top plate.

In an exemplary implementation, 45 pairs (90 in total) of parallel conductors 2120 are deposited on a square structured ceramic top plate 2130 . The line width of the conductors 2120 is 3 mm each, with a space of 1.5 mm (therefore, the conductors are arranged at a pitch of 4.5 mm). The conductors may be 400mm long, with vertical feedthroughs through the ceramic top plate 2130, and electrical connections made on the backside at atmospheric pressure. Every other electrode is connected to the bus on one side, and the remaining (alternating) electrodes are each connected to the bus on the other side, forming two arrays. RF power at 60 MHz with a 180 degree phase difference was connected across the two arrays.

Referring to FIG. 15B, a plurality of grooves 2136 may be formed in the bottom surface 2130a of the dielectric top plate 2130, and the conductors 2120 may be cut into the grooves. The grooves 2136 may be arranged as parallel linear stripes.

In some implementations, each conductor 2120 is a portion of a wire 2150 . Wires 2150 may fit into their corresponding grooves 2136 . Wire 2150 may include a sheath surrounding and protecting conductor 2120 . The wire 2150 may be provided by the various wires 300 described with reference to Figures 3A-C.

Referring to FIG. 15C , in some implementations, the conductors 2120 can be provided by a conductive coating on the top plate 2130 . For example, conductor 2120 may be a stripline electrode plated on ceramic top plate 2130 . Each conductor 2120 may be a coating on one or more interior surfaces of individual slots 2136 . The space between conductors 2120 and base plate 2132 may provide conduits 2450 . Conduit 2450 may carry fluid as described in Figure 3A.

Plasma simulations were performed using a 2-D model to study the dependence of plasma parameters on gas pressure. The computational domain extends over two half-pairs of electrodes. Assume that the process conditions are 1450sccm Argon+50sccm N ₂ per source, 6Torr, 200W per pair of half electrode. Simulations show that the plasma density is generally higher in the region below the electrodes. Ar+ density and electron density are similar ( _N2 + density is much lower), mainly due to the high ratio of argon to _N2 gas supply.

Certain embodiments of the invention have been described. While this specification contains many specific implementation details, many other variations are possible. For example: • The workpiece can be moved linearly through a series of chambers, eg on a belt or linear actuation stage rather than a rotating stage. Additionally, the workpiece may be stationary, eg, the workpiece support does not move relative to the wire. • Connect RF power to the conductor bus at the center, end, or other location of the bus, or a combination of locations on the bus. • Grounding of the electrode bus may be performed at the center, end, or other location or combination of locations of the bus. · The RF power supply can apply signals in the RF, VHF, UHF or microwave range.

Other embodiments are within the scope of the following claims.

100‧‧‧processing tool 102‧‧‧chamber body 104‧‧‧internal space 106‧‧‧support 108‧‧‧top electrode 110‧‧‧gas distributor

112: Gas supply

113: vacuum pump

114: workpiece support

114a: workpiece support surface

115: Workpiece

116: workpiece support electrode

118: Workpiece bias voltage supply

119: Internal channel

120: Electrode assembly in the chamber

122: RF power supply

123: opening

124: Balun

130: top clearance

132: Bottom clearance

133: Bottom inner space

140: RF ground

142:RF bias power generator

144: Impedance matching

146: Fluid supply

148: heat exchanger

150: axis

152: Actuator

154: drive shaft

200: Processing Tools

202‧‧‧Cylindrical chamber body 204‧‧‧inner space 206‧‧‧support 208‧‧‧top electrode 210‧‧‧gas inlet 220‧‧‧electrode assembly 220a‧‧‧electrode assembly 220b‧‧‧electrode Assembly 221‧‧‧outer wall 221a‧‧‧roof 260‧‧‧precursor station 260a‧‧‧first precursor station 270‧‧‧radial spacer 280‧‧‧precursor processing area 280a‧‧‧precursor processing Area 280b‧‧‧second precursor processing area 281‧‧‧gas isolation area 282‧‧‧first pumping area 283‧‧‧cleaning area 284‧‧‧second pumping area 285a‧‧‧plasma processing area 285b‧‧‧second plasma treatment area 300‧‧‧wire 302‧‧‧wire 304‧‧‧wire 310‧‧‧conductor 320‧‧‧cylindrical shell 330‧‧‧channel 340‧‧‧hollow channel 400‧ ‧‧electrode assembly 402 in the chamber‧‧‧support 410‧‧‧spacing 412‧‧‧plasma region 414‧‧‧upper plasma region 416‧‧‧lower plasma region 422‧‧‧RF power supply 422a‧‧‧ First terminal 422b‧‧‧second terminal 510‧‧‧first electrode subassembly 520‧‧‧second electrode subassembly 522‧‧‧first electrode subassembly 524‧‧‧first electrode subassembly 530‧‧‧ First bus 532‧‧‧second electrode subassembly 534‧‧‧second electrode subassembly 540‧‧‧second bus 550‧‧‧third bus 560‧‧‧fourth bus 580‧‧‧adjustable impedance 590 ‧‧‧Central feed 592‧‧‧X-shaped current separator 600‧‧‧Electrode assembly 601‧‧‧Electrode assembly 602‧‧‧First end 604‧‧‧Second end 605‧‧‧Bisector 610‧‧ ‧Coplanar wire 620‧‧‧frame 622‧‧‧notch 624‧‧‧wedge electrode 625‧‧‧upper part 626‧‧‧inside wall 627‧‧‧opening 650‧‧‧handling tool 700‧‧‧electrode assembly 702‧ ‧‧electrode assembly 704‧‧‧electrode assembly 706‧‧‧electrode assembly 710‧‧‧wire 712‧‧‧coplanar wire 714‧‧‧coplanar wire 730‧‧‧first bus 732‧‧‧first bus 734 . ‧‧Second end 754‧‧‧First end 755‧‧‧Second end 756‧‧‧Drive point 800‧‧‧Electrode assembly 801‧‧‧Switchable electrode system 802‧‧‧Switchable electrode system 804‧‧ ‧Switchable electrode system 806‧‧‧Switchable electrode system 808‧‧‧Switchable electrode system 810‧‧‧Wire 811‧‧‧First end 812‧‧‧Second end 816‧‧‧First multiplex 817‧ ‧‧Second multiplex 820‧‧‧First bus 821‧‧‧Third terminal 822‧ ‧‧second bus 824‧‧‧third bus 826‧‧‧fourth bus 828‧‧‧fourth bus 830‧‧‧first RF switch 831‧‧‧first terminal 832‧‧‧second terminal 834‧ ‧‧second RF switch 836‧‧‧third RF switch 838‧‧‧fourth RF switch 838840‧‧‧first tap 842‧‧‧second tap 844‧‧‧tap 846‧‧‧tap 848‧‧‧tap 850‧‧‧first RF switch group 854‧‧‧second RF switch group 856‧‧‧third RF switch group 858‧‧‧fourth RF switch group 860‧‧‧sub-switch 860a- 860h‧‧‧sub switch 870‧‧‧first RF switch group 874‧‧‧second RF switch group 876‧‧‧third RF switch group 878‧‧‧fourth RF switch group 900‧‧‧switchable electrode system 902‧‧‧switchable electrode assembly 940‧‧‧tap 942‧‧‧tap 1000‧‧‧switchable electrode assembly 1010‧‧‧wedge electrode assembly 1030‧‧‧first RF switch 1034‧‧‧second RF Switch 1036‧‧‧Third RF Switch 1038‧‧‧Fourth RF Switch 1040‧‧‧Tap 1100‧‧‧PIN Diode Switch 1102‧‧‧Saturable Inductor Switch 1110‧‧‧PIN Diode 1120 ‧‧‧first capacitor 1122‧‧‧second capacitor 1124‧‧‧first capacitor 1126‧‧‧second capacitor 1131‧‧‧first terminal 1132‧‧‧second terminal 1134‧‧‧control terminal 1135‧‧ ‧Control terminal 1136‧‧‧Control signal buffer amplifier 1137‧‧‧Control signal buffer amplifier 1138‧‧‧Low-pass filter 1140‧‧‧Inductor 1150‧‧‧Inductor 1160‧‧‧Saturable inductor 1162‧‧ ‧Primary winding 1164 ‧‧‧Control winding 1200 ‧‧‧Frequency based switch 1200a‧‧‧First frequency based switch 1200b‧‧‧Second frequency based switch 1204‧‧‧Frequency switched electrode system 1220‧‧‧ First capacitor 1222‧‧‧second capacitor 1231‧‧‧first terminal 1232‧‧‧second terminal 1240‧‧‧first inductor 1242‧‧‧second inductor 1250a‧‧‧first frequency selective terminal 1250b‧‧‧second frequency selective terminal 1260‧‧‧tap 2100‧‧‧plasma reactor 2102‧‧‧chamber body 2102a‧‧‧side walls 2102b‧‧‧top plate 2102c‧‧‧bottom plate 2104‧‧‧ Interior Space 2106‧‧‧Electrode Assembly 2110‧‧‧Port 2112‧‧‧Gas Supply 2113‧‧‧Vacuum Pump 2114‧‧‧Workpiece Support 2114a‧‧‧Workpiece Support Surface 2116‧‧‧Workpiece Support Electrode 2118‧‧‧Workpiece Bias voltage supply 2119‧‧‧internal channel 2 120‧‧‧Plurality of Conductors 2122‧‧‧RF Power Supply 2130‧‧‧Dielectric Top Plate 2130a‧‧‧Bottom Surface 2132‧‧‧Bottom Plate 2136‧‧‧Slot 2142‧‧‧RF Bias Power Generator 2144‧‧‧ Impedance matching 2146‧‧‧fluid supply 2148‧‧‧heat exchanger 2150‧‧‧radiator 2152‧‧‧passage 2154‧‧‧heat exchanger 2200‧‧‧processing tool 2202‧‧‧body 2202a‧‧‧side wall 2202b ‧‧‧top plate 2202c‧‧‧bottom plate 2204‧‧‧internal space 2204a-2204d‧‧‧chamber 2210‧‧‧obstacle 2214‧‧‧workpiece support 2214a‧‧‧workpiece support surface 2260‧‧‧shaft 2262 ‧‧‧Motor 2270‧‧‧obstacle 2272‧‧‧obstacle 2280‧‧‧pump-purification system 2282‧‧‧first channel 2284‧‧‧second channel 2286‧‧‧third channel 2450‧‧ ‧Conduit H ₁ ‧‧‧First Gap Height H ₂ ‧‧‧Second Gap Height R ₁ ‧‧‧Inner Radius R ₂ ‧‧Outer Radius S‧‧‧Interval θca‧‧‧Central Angle

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the present invention will be apparent from the description, drawings and claims.

Description of drawings

Figure 1 is a schematic side view of an example of a processing tool including a plasma chamber.

2A is a schematic top view of an example of a processing tool including a plasma chamber.

2B-2C are cross-sectional side views of the processing tool of FIG. 2A along section lines B-B and C-C, respectively.

3A-3C are schematic cross-sectional perspective views of various examples of wires of an electrode assembly within a chamber.

Figure 4A is a schematic top view of a portion of an electrode assembly within a chamber.

4B-C are cross-sectional schematic side views of an electrode assembly in a chamber with different states of the plasma domain.

5A-D are schematic top views of various examples of electrode assembly configurations within a chamber.

Figure 6A is a schematic top view of an example of a processing tool.

6B is a schematic top view of an example of a wedge-shaped electrode assembly.

6C is a schematic top view of an example of a frame of a wedge-shaped electrode assembly.

6D is a cross-sectional side view of an example of a frame of a wedge-shaped electrode assembly.

6E is a schematic top view of an example of a wedge-shaped electrode assembly.

7A-7D are conceptual schematic diagrams of examples of electrical configurations of wedge-shaped electrode assemblies.

8A is a schematic top view of an example of an electrode assembly.

8B-8F are conceptual schematic diagrams of examples of electrical configurations of switched electrode assemblies.

9A-9B are conceptual schematic diagrams of examples of mode-selectable switched electrode systems.

10 is a conceptual schematic diagram of an example of a switched wedge electrode system.

11A is a schematic diagram of an example of a PIN diode switch.

11B is a schematic diagram of an example of a saturable inductive switch.

12A is a schematic diagram of an example of a frequency-based switch.

12B-C are conceptual schematic diagrams of examples of electrical configurations of frequency-switched electrode systems.

Figure 13 is a schematic side view of an example of a plasma reactor.

Figure 14A is a schematic top view of another example of a plasma reactor.

14B and 14C are schematic side views of the plasma reactor of FIG. 14A along lines 14B-14B and 14C-14C, respectively.

15A-15C are schematic cross-sectional views of electrode assemblies.

The same numerical designations in different drawings represent the same elements.

Domestic deposit information (please note in order of depositor, date, and number) None

Overseas storage information (please note in order of storage country, institution, date, number) None

100: Handling tools

102: Chamber body

104: Internal space

106: support

108: Top electrode

110: gas distributor

112: Gas supply

113: vacuum pump

114: workpiece support

114a: workpiece support surface

115: Workpiece

116: workpiece support electrode

118: Workpiece bias voltage supply

119: Internal channel

120: Electrode assembly in the chamber

122: RF power supply

123: opening

124: Balun

130: top clearance

132: Bottom clearance

133: Bottom internal space

140: RF ground

142:RF bias power generator

144: Impedance matching

146: Fluid supply

148: heat exchanger

150: axis

152: Actuator

154: drive shaft

Claims (37)

A processing tool for a plasma processing, the processing tool includes: a chamber body, the chamber body has an interior space, the interior space provides a plasma chamber; a frame, the frame has an upper, from Sidewalls extending downwardly from the upper portion and a floor extending inwardly from the sidewalls, the floor having an opening through the floor to the plasma chamber, wherein the opening is wedge-shaped and a portion of the opening a width less than a width of an internal volume of the frame between the side walls; an electrode assembly held by the frame, the electrode assembly comprising a plurality of coplanar wires laterally extending through the interior volume of the frame and between the sidewalls and above the opening, each of the plurality of wires comprising a conductor, wherein the plurality of wires are at a different angle relative to a centerline of the opening oriented, and wherein the different angles vary monotonically in the wedge-shaped opening from an apex of the wedge-shaped opening to a base of the wedge-shaped opening so that each of the plurality of filaments is equal in length across the wedge-shaped opening; a a workpiece support holding a workpiece in the plasma chamber such that at least a portion of a front surface of the workpiece faces the opening in the floor of the frame; an actuator in the Chamber body and the workpiece support Relative motion is generated between, so that the opening laterally (laterally) moves across (across) the workpiece; a gas distributor, the gas distributor delivers a process gas to the plasma chamber; and a first RF A power supply, the first RF power supply provides a first RF power to the conductors of the electrode assembly to form a plasma. The processing tool of claim 1, wherein the workpiece support is rotatable about an axis of rotation, and the actuator rotates the workpiece support such that rotation of the support carries the workpiece across the opening. The processing tool of claim 2, wherein the plurality of coplanar filaments extend across the wedge-shaped opening. The processing tool of claim 3, wherein the plurality of coplanar filaments comprises a plurality of linear filaments, and different filaments have different lengths to define the wedge-shaped opening. The processing tool as claimed in claim 4, wherein the plurality of coplanar filaments extend in parallel. The processing tool as claimed in claim 4, wherein the different angles provide a relative orientation of the plurality of coplanar filaments such that a plasma density generated in the wedge-shaped opening is higher at the apex of the wedge-shaped opening than at the apex of the wedge-shaped opening The base of the wedge-shaped opening is low. The processing tool of claim 3, wherein the plurality of coplanar filaments are oriented to have an orientation relative to the workpiece below the opening A longitudinal axis whose direction of motion forms a non-zero angle. The processing tool as claimed in claim 7, wherein the non-zero angle is greater than 10°. The processing tool as claimed in claim 1, wherein the ends of the conductors of the plurality of coplanar filaments are connected to the first RF power source through a recursive RF feed structure. The processing tool as claimed in claim 1, wherein opposite ends of the conductors of the plurality of coplanar filaments are connected to a common bus, and the common bus is connected to the first RF power source at two opposite positions. A plasma reactor comprising: a chamber body having an interior space providing a plasma chamber; a gas distributor delivering a process gas to the plasma a chamber; a pump coupled to the plasma chamber to evacuate the chamber; a workpiece support holding a workpiece; an inner chamber electrode assembly comprising a plurality of wires, The plurality of filaments extend laterally through the plasma chamber between a ceiling of the plasma chamber and the workpiece support, each filament comprising a conductor surrounded by a cylindrical insulating shell, wherein the plurality of The filaments comprise a first multifilament and a second multifilament, the second multifilament and the first multifilament The wires are arranged in an alternating pattern; a first bus and a second bus, the first bus is coupled to the first multifilament, the second bus is coupled to the second multifilament; an RF power supply, the RF a power supply to apply an RF signal to the chamber electrode assembly; and at least one RF switch configured to controllably electrically couple and decouple the first bus to one of: i ) ground, ii) the RF power supply, or iii) the second bus. The plasma reactor as claimed in claim 11, wherein the at least one RF switch comprises a plurality of RF switches connected in parallel between the first bus and one of: i) ground, ii) the RF power supply or iii) the second bus. The plasma reactor of claim 11, wherein the at least one RF switch is configured to controllably electrically couple and decouple the first bus and the second bus. The plasma reactor as claimed in claim 13, wherein the at least one RF switch comprises a plurality of switches connected in parallel between different pairs of positions on the first bus and the second bus to controllably connect the second A bus is electrically coupled and decoupled from the second bus. The plasma reactor as claimed in claim 11, wherein the at least one RF switch comprises a first switch configured to controllably electrically couple and decouple the first bus line to and from ground, and comprises to There is one less second RF switch configured to controllably electrically couple and decouple the second bus from ground. The plasma reactor as claimed in claim 15, wherein the at least one RF switch includes a first plurality of switches connected in parallel between different positions on the first bus and ground, and the at least one second switch is included in A second plurality of switches connected in parallel between different positions on the second bus and ground. The plasma reactor of claim 16, wherein different positions on the first bus comprise opposite ends of the first bus, and different positions on the second bus comprise opposite ends of the second bus. The plasma reactor of claim 11, wherein the at least one RF switch comprises a first switch configured to controllably electrically couple and decouple the first bus to and from the RF power supply, and At least one second RF switch configured to controllably electrically couple and decouple the second bus to and from the RF power source is included. The plasma reactor as claimed in claim 18, wherein the at least one RF switch comprises a first plurality of switches connected in parallel between different positions on the first bus and the RF power supply, and the at least one second switch A second plurality of switches connected in parallel between different locations on the second bus and the RF power supply are included. The plasma reactor as recited in claim 18, wherein the at least one RF switch is included at a different location on the first bus from the A first plurality of switches connected in parallel between the RF power supplies, and the at least one second switch includes a second plurality of switches connected in parallel between different locations on the second bus and ground. The plasma reactor as claimed in claim 19 or 20, wherein different positions on the first bus comprise opposite ends of the first bus, and different positions on the second bus comprise opposite ends of the second bus. The plasma reactor as claimed in claim 11, comprising: a third bus and a fourth bus, the third bus is coupled to the first multifilament, the fourth bus is coupled to the second multifilament, wherein the plurality of filaments have a plurality of first ends and a plurality of second ends, and the first ends of each corresponding filament are closer to a first sidewall of the plasma chamber than the second ends of the corresponding filaments, and wherein the first A bus is coupled to the first ends of the first multiplex, the second bus is coupled to the first ends of the second multiplex, the third bus is coupled to the first multiplex The second ends of the wires, and the fourth bus are coupled to the second ends of the second multi-wire. The plasma reactor of claim 22, wherein the at least one RF switch is configured to controllably electrically couple and decouple the first bus and the second bus, and includes at least one second RF switch, the A second RF switch is configured to controllably electrically couple and decouple the third bus with the fourth bus. The plasma reactor of claim 22, wherein the at least one RF switch comprises a first switch configured to controllably electrically couple and decouple the first bus line to and from ground, and comprises at least A second RF switch configured to controllably electrically couple and decouple the third bus to ground. The plasma reactor of claim 22, wherein the at least one RF switch comprises a first switch configured to controllably electrically couple and decouple the first bus line to and from ground, and comprises at least a second RF switch, at least one third RF switch configured to controllably couple the second bus to and decouple electrically from the RF power supply, the third RF switch configured to controllably couple The third bus is electrically coupled to and decoupled from ground and includes at least one fourth RF switch configured to controllably electrically couple and decouple the fourth bus from the RF power supply. The plasma reactor of claim 22, wherein the at least one RF switch comprises a first switch configured to controllably electrically couple and decouple the first bus to and from the RF power supply, and including at least one second RF switch, at least one third RF switch configured to controllably electrically couple and decouple the second bus with the RF power supply, the third RF switch configured to controllably electrically coupling and decoupling the third bus to an RF power source, and including at least one fourth RF switch configured to controllably The fourth bus is electrically coupled and decoupled from the RF power supply. A plasma reactor comprising: a chamber body having an interior space providing a plasma chamber; a gas distributor delivering a process gas to the plasma a chamber; a pump coupled to the plasma chamber to evacuate the chamber; a workpiece support holding a workpiece; an inner chamber electrode assembly comprising a plurality of wires, The plurality of wires extend laterally through the plasma chamber between a ceiling of the plasma chamber and the workpiece support, each wire comprising a conductor surrounded by a cylindrical insulating shell; a bus, the a bus outside the chamber and coupled to opposite ends of the plurality of wires; an RF power supply that applies an RF signal to the electrode assembly within the chamber; and a plurality of RF switches configured to control Ground electrically couples and decouples a plurality of different locations on the bus to one of: i) ground or ii) the RF power supply. A plasma reactor comprising: a chamber body having an interior space providing a plasma chamber; A gas distributor that delivers a process gas to the plasma chamber; a workpiece support that holds a workpiece; an electrode assembly that includes a plurality of conductors, the plurality of conductors extending parallel and laterally across a region spanning a desired location of the workpiece on the workpiece support in a coplanar array; an RF power supply providing a first RF power to the electrode assembly; and a dielectric bottom plate between the electrode assembly and the workpiece support, the dielectric bottom plate provides an RF window between the electrode assembly and the plasma chamber; a dielectric top plate, the dielectric The electrical top plate has a lower surface with a plurality of parallel grooves; and a plurality of wires in the plurality of parallel grooves between the dielectric top plate and the RF window, each wire comprising a single conductor of the conductors and a non-metallic shell surrounding the single conductor and positioned between the dielectric top plate and the RF window, wherein the shell forms a conduit and the single conductor extends as a solid wire through the conduit and suspended in the conduit with a gap surrounding the single conductor and separating the single conductor from the shell such that the single conductor is spaced from an inner floor of the shell. The plasma reactor as claimed in claim 28, wherein the dielectric top plate is a ceramic body, and the dielectric bottom plate is quartz or silicon nitride. The plasma reactor of claim 28, wherein the plurality of conductors includes a first plurality of conductors and a second plurality of conductors, the second plurality of conductors being arranged in an alternating pattern with the first plurality of conductors, and The RF power supply is configured to apply a first RF input signal to the first multiple conductor, and apply a second RF input signal to the second multiple conductor. The plasma reactor of claim 30, wherein the RF power supply is configured to generate the first RF input signal and the second RF input signal at the same frequency. The plasma reactor of claim 31, wherein the RF power supply is configured to provide an adjustable phase difference between the first RF input signal and the second RF input signal. The plasma reactor of claim 30, wherein the plurality of conductors have a plurality of first ends on a first side of the plasma chamber and have a plurality of first ends on an opposite second side of the plasma chamber a plurality of second ends. The plasma reactor of claim 33, wherein the RF power supply is configured to apply the first RF input signal to the first end of the first multiconductor, and apply the second RF input signal to the The second end of the second multiple conductor. The plasma reactor of claim 34, wherein the second end of the first multiconductor is floating, and the first end of the second multiconductor is floating. The plasma reactor as claimed in claim 34, wherein the first ends of the first multiconductor are connected to a first common bus, and the second ends of the second multiconductor are connected to a first Two share the bus. The plasma reactor of claim 34, wherein the second ends of the first multiconductor are grounded, and the first ends of the second multiconductor are grounded.

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