Paired Dynamic Parallel Plate Capacitively Coupled Plasma

Abstract

A processing chamber having a plurality of processing stations and respective wafer support surfaces is described. The processing stations and wafer support surfaces are arranged such that there are an equal number of processing stations and heaters. An RF generator is connected to a first electrode in a first station and a second electrode in a second station. A bottom RF path is formed via a connection between the first support surface and the second support surface.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to apparatus for semiconductor wafer processing. More particularly, embodiments of the present disclosure relate to a processing chamber having a parallel plate capacitively coupled plasma and a method of generating the plasma. Background Art

[0002] Atomic layer deposition (ALD) and plasma enhanced ALD (PEALD) are deposition techniques that provide control over film thickness and conformality in high aspect ratio structures. Due to the continuous reduction in device size in the semiconductor industry, there is an increasing interest and applications using ALD / PEALD. In some cases, only PEALD can meet the desired film thickness and conformality specifications.

[0003] Semiconductor device formation is typically performed in a substrate processing platform containing multiple chambers. In some cases, the purpose of a multi-chamber processing platform or cluster tool is to perform two or more processes on a substrate sequentially in a controlled environment. However, in other cases, a multi-chamber processing platform may only perform a single processing step on a substrate; the additional chamber is intended to maximize the rate at which the substrate is processed by the platform. In the latter case, the processing performed on the substrate is typically a batch process, in which a relatively large number of substrates (e.g., 25 or 50) are processed simultaneously in a given chamber. Batch processing is particularly beneficial for processes that are too time-consuming to perform on individual substrates in an economically feasible manner, such as atomic layer deposition (ALD) processes and some chemical vapor deposition (CVD) processes.

[0004] Capacitively coupled plasma (CCP) is a well-proven method for generating uniform plasma and is ideal for many plasma processing applications used in semiconductor manufacturing. When one of the electrodes of the CCP, where the silicon wafer is typically placed, needs to be physically moved immediately before and after or during processing, the traditional arrangement requires the electrical connection for the ground path to be disconnected in situ, making this implementation nearly impossible.

[0005] Therefore, there is a need in the art for an apparatus to provide a uniform plasma in a parallel plate capacitively coupled plasma for batch processing. Summary of the invention

[0006] One or more embodiments of the present disclosure are directed to a processing chamber comprising at least two plasma stations and a wafer pedestal having a plurality of support surfaces to support respective wafers for processing. An RF generator is connected to a first electrode in a first plasma processing station and a second electrode in a second plasma processing station to form a top RF path. A connection is present between at least two support surfaces of the wafer pedestal to form a bottom RF path.

[0007] One or more embodiments of the present disclosure relate to a processing chamber comprising: a plurality of processing stations arranged around an interior of the processing chamber, the plurality of processing stations comprising at least two plasma stations; a wafer pedestal having a plurality of heaters to support respective wafers for processing, the number of heaters being equal to the number of processing stations; an RF generator connected to a first electrode in a first plasma processing station and a second electrode in a second plasma processing station to form a top RF path; and a connector between the first heater and the second heater of the wafer pedestal to form a bottom RF path.

[0008] Further embodiments of the present disclosure relate to methods of processing a plurality of substrates. An RF generator connected to a first electrode in a first plasma processing station and a second electrode in a second plasma processing station to form a top RF path is powered. The first plasma processing station includes a first support surface, and the second plasma processing station includes a second support surface. A connection is present between the first support surface and the second support surface of a wafer pedestal to form a bottom RF path. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order that the manner in which the above-described features of the present disclosure may be understood in detail, a more particular description of the present disclosure, briefly summarized above, may be obtained by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered limiting of its scope, as the present disclosure may admit to other equally effective embodiments.

[0010] Figure 1 shows a cross-sectional view of a batch processing chamber according to one or more embodiments of the present disclosure;

[0011] Figure 2 shows a partial perspective view of a batch processing chamber according to one or more embodiments of the present disclosure;

[0012] Figure 3 shows a schematic diagram of a batch processing chamber according to one or more embodiments of the present disclosure;

[0013] Figure 4 A schematic diagram illustrating a portion of a wedge-shaped gas distribution assembly for use in a batch processing chamber according to one or more embodiments of the present disclosure;

[0014] Figure 5 shows a schematic diagram of a batch processing chamber according to one or more embodiments of the present disclosure;

[0015] Figure 6A gas distribution assembly having openings for a gas injector insert according to one or more embodiments of the present disclosure is shown;

[0016] Figure 7 shows a schematic diagram of a processing chamber according to one or more embodiments of the present disclosure;

[0017] Figure 8 shows a schematic diagram of a processing chamber according to one or more embodiments of the present disclosure;

[0018] Fig. 9 shows a schematic diagram of a processing chamber according to one or more embodiments of the present disclosure;

[0019] Fig.10 shows a schematic diagram of a processing chamber according to one or more embodiments of the present disclosure;

[0020] Fig.11 shows a schematic diagram of a processing chamber according to one or more embodiments of the present disclosure;

[0021] Fig.12 A schematic diagram illustrating a processing chamber according to one or more embodiments of the present disclosure; and

[0022] Fig.13 A schematic diagram of a processing chamber according to one or more embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0023] Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of construction or processing steps set forth in the following description. The present disclosure is capable of other embodiments and can be practiced or carried out in various ways.

[0024] As used herein, "substrate," "substrate surface," or the like refers to any substrate or material surface formed on a substrate on which processing is performed. For example, depending on the application, substrate surfaces on which processing may be performed include, but are not limited to, materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. Substrates may be exposed to pretreatment processes to polish, etch, reduce, oxidize, hydroxylate (or otherwise create or graft target chemical moieties to impart chemical functionality), anneal, and / or bake the substrate surface. In addition to performing processing directly on the surface of the substrate itself, in the present disclosure, any film processing steps disclosed may also be performed on an underlying layer formed on the substrate, as disclosed in more detail below, and the term "substrate surface" is meant to include such underlying layers as indicated by the context. Thus, for example, where a film / layer or portion of a film / layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface. What a given substrate surface contains will depend on the material to be deposited and the specific chemistry used.

[0025] As used in this specification and the appended claims, the terms "reactive compound," "reactive gas," "reactive species," "precursor," "processing gas," and the like are used interchangeably to refer to a substance having a species capable of reacting with a substrate surface or a material on the substrate surface in a surface reaction (e.g., chemisorption, oxidation, reduction). For example, a first "reactive gas" may simply adsorb onto the surface of a substrate and be available for further chemical reaction with a second reactive gas.

[0026] As used herein, "atomic layer deposition" or "cyclic deposition" refers to the sequential exposure of two or more reactive compounds to deposit a layer of material on a substrate surface. The substrate (or a portion of the substrate) is separately exposed to two or more reactive compounds introduced into a reaction zone of a processing chamber. In a time-domain ALD process, the exposure of each reactive compound is separated by a time delay to allow each compound to adhere and / or react on the substrate surface and then be cleared from the processing chamber. The reactive compounds are said to be exposed to the substrate sequentially. In a spatial ALD process, different portions of the substrate surface (or material on the substrate surface) are simultaneously exposed to two or more reactive compounds, so that any given point on the substrate is not substantially exposed to more than one reactive compound at the same time. As used in this specification and the appended claims, the term "substantially" used in this regard means (as will be understood by those skilled in the art) that there is a possibility that a small portion of the substrate may be exposed to multiple reactive gases simultaneously due to diffusion, and that such simultaneous exposure is unintentional.

[0027] As used in this specification and the appended claims, the terms "pie-shaped" and "wedge-shaped" may be used interchangeably to describe a body that is a sector of a circle. For example, a wedge-shaped segment may be part of a circular or disk-shaped structure, and multiple wedge-shaped segments may be connected to form a circular body. A sector may be defined as a portion of a circle enclosed by two radii of a circle and an intersecting arc. The inner edge of a pie-shaped segment may reach a point or may be truncated to a flat edge or a circle. In some embodiments, a sector may be defined as a portion of a ring or annulus.

[0028] The path of the substrate may be perpendicular to the gas ports. In some embodiments, each of the gas injector assemblies comprises a plurality of elongated gas ports extending in a direction substantially perpendicular to the path traversed by the substrate, wherein the front face of the gas distribution assembly is substantially parallel to the platen. As used in this specification and the appended claims, the term "substantially perpendicular" means that the general direction of movement of the substrate is along a plane that is substantially perpendicular (e.g., about 45° to 90°) to the axis of the gas ports. For wedge-shaped gas ports, the axis of the gas ports may be considered to be a line defined as the midpoint of the width of the port extending along the length of the port.

[0029] Figure 1A cross section of a processing chamber 100 is shown, which includes a gas distribution assembly 120 (also referred to as an injector or injector assembly) and a susceptor assembly 140. The gas distribution assembly 120 is any type of gas delivery device used in a processing chamber. The gas distribution assembly 120 includes a front surface 121 facing the susceptor assembly 140. The front surface 121 can have any number or type of openings to deliver a gas flow toward the susceptor assembly 140. The gas distribution assembly 120 also includes a peripheral edge 124, which in the illustrated embodiment is substantially circular.

[0030] The specific type of gas distribution assembly 120 used may vary depending on the specific process used. Embodiments of the present disclosure may be used with any type of processing system in which the gap between the susceptor and the gas distribution assembly is controlled. Although various types of gas distribution assemblies (e.g., showerheads) may be employed, embodiments of the present disclosure may be particularly useful for spatial ALD gas distribution assemblies having multiple substantially parallel gas channels. As used in this specification and the accompanying claims, the term "substantially parallel" means that the elongated axes of the gas channels extend in the same general direction. There may be slight defects in the parallelism of the gas channels. The multiple substantially parallel gas channels may include at least one first reaction gas A channel, at least one second reaction gas B channel, at least one purge gas P channel, and / or at least one vacuum V channel. Gases flowing out of (multiple) first reaction gas A channels, (multiple) second reaction gas B channels, and (multiple) purge gas P channels are directed toward the top surface of the wafer. Some gas flows move horizontally across the surface of the wafer and leave the processing area through the purge gas P channel. A substrate moving from one end of the gas distribution assembly to the other end will be exposed to each process gas in turn, thereby forming a layer on the substrate surface.

[0031] In some embodiments, the gas distribution assembly 120 is a rigid body made of a single injector unit. In one or more embodiments, the gas distribution assembly 120 is composed of multiple separate sectors (e.g., injector units 122), such as Figure 2 Either a one-piece body or a multi-sector body may be used with the various embodiments of the present disclosure described.

[0032] The susceptor assembly 140 is located below the gas distribution assembly 120. The susceptor assembly 140 includes a top surface 141 and at least one recess 142 in the top surface 141. The susceptor assembly 140 also has a bottom surface 143 and an edge 144. The recess 142 can be of any suitable shape and size, depending on the shape and size of the substrate 60 being processed. Figure 1In the illustrated embodiment, the groove 142 has a flat bottom to support the bottom of the wafer; however, the bottom of the groove can vary. In some embodiments, the groove has a step area around the peripheral edge of the groove that is sized to support the peripheral edge of the wafer. The amount of the peripheral edge of the wafer supported by the step can vary depending on, for example, the thickness of the wafer and the presence of features already present on the back side of the wafer.

[0033] In some embodiments, Figure 1 As shown, the size of the groove 142 in the top surface 141 of the susceptor assembly 140 is designed so that the substrate 60 supported in the groove 142 has a top surface 61 that is substantially coplanar with the top surface 141 of the susceptor 140. As used in this specification and the accompanying claims, the term "substantially coplanar" means that the top surface of the wafer and the top surface of the susceptor assembly are coplanar within ±0.2 mm. In some embodiments, the top surface is coplanar within ±0.15 mm, ±0.10 mm, or ±0.05 mm. The groove 142 of some embodiments supports the wafer so that the inner diameter (ID) of the wafer is within a range of about 170 mm to about 185 mm from the center (rotation axis) of the susceptor. In some embodiments, the groove 142 supports the wafer so that the outer diameter (OD) of the wafer is within a range of about 470 mm to about 485 mm from the center (rotation axis) of the susceptor.

[0034] Figure 1 The pedestal assembly 140 includes a support column 160 that can lift, lower, and rotate the pedestal assembly 140. The pedestal assembly may include a heater or gas line, or electrical components within the center of the support column 160. The support column 160 may be the primary means of increasing or decreasing the gap between the pedestal assembly 140 and the gas distribution assembly 120, thereby moving the pedestal assembly 140 to the appropriate position. The pedestal assembly 140 may also include a fine adjustment actuator 162 that can fine-tune the pedestal assembly 140 to create a predetermined gap 170 between the pedestal assembly 140 and the gas distribution assembly 120. In some embodiments, the distance of gap 170 is in the range of about 0.1 mm to about 5.0 mm, or in the range of about 0.1 mm to about 3.0 mm, or in the range of about 0.1 mm to about 2.0 mm, or in the range of about 0.2 mm to about 1.8 mm, or in the range of about 0.3 mm to about 1.7 mm, or in the range of about 0.4 mm to about 1.6 mm, or in the range of about 0.5 mm to about 1.5 mm, or in the range of about 0.6 mm to about 1.4 mm, or in the range of about 0.7 mm to about 1.3 mm, or in the range of about 0.8 mm to about 1.2 mm, or in the range of about 0.9 mm to about 1.1 mm, or about 1 mm.

[0035] The processing chamber 100 shown in the figure is a turntable chamber, in which the susceptor assembly 140 can hold a plurality of substrates 60. Figure 2 As shown, the gas distribution assembly 120 may include a plurality of individual injector units 122, each of which is capable of depositing a film on a wafer while the wafer is moved below the injector unit. Two pie-shaped injector units 122 are illustrated as being positioned on substantially opposite sides of the base assembly 140 and above the base assembly 140. This number of injector units 122 is illustrated for illustrative purposes only. It will be understood that more or fewer injector units 122 may be included. In some embodiments, there are a sufficient number of pie-shaped injector units 122 to form a shape that conforms to the shape of the base assembly 140. In some embodiments, each of the individual pie-shaped injector units 122 may be independently moved, removed and / or replaced without affecting any other injector unit 122. For example, a section may be raised to allow a robot to enter the area between the base assembly 140 and the gas distribution assembly 120 to load / unload the substrate 60.

[0036] A processing chamber with multiple gas injectors can be used to process multiple wafers simultaneously so that the wafers undergo the same process flow. Figure 3 As shown, the processing chamber 100 has four gas injector assemblies and four substrates 60. At the beginning of processing, the substrate 60 can be positioned between the injector assemblies 30. Rotating the pedestal assembly 140 45° will cause each substrate 60 between the gas distribution assemblies 120 to be moved to the gas distribution assembly 120 for film deposition, as shown by the dashed circle below the gas distribution assembly 120. Another 45° rotation will move the substrate 60 away from the injector assembly 30. With a spatial ALD injector, a film is deposited on the wafer during the movement of the wafer relative to the injector assembly. In some embodiments, the pedestal assembly 140 is rotated in an incremental manner, which prevents the substrate 60 from stopping under the gas distribution assembly 120. The number of substrates 60 and gas distribution assemblies 120 may be the same or different. In some embodiments, the number of wafers being processed is the same as the gas distribution assembly. In one or more embodiments, the number of wafers being processed is a fraction or an integer multiple of the number of gas distribution assemblies. For example, if there are four gas distribution assemblies, then 4x wafers are being processed, where x is an integer value greater than or equal to one.

[0037] Figure 3The process chamber 100 illustrated in the drawings represents only one possible configuration and should not be considered to limit the scope of the present disclosure. Here, the process chamber 100 includes a plurality of gas distribution assemblies 120. In the illustrated embodiment, there are four gas distribution assemblies (also referred to as injector assemblies 30) evenly spaced around the process chamber 100. The process chamber 100 is shown to be octagonal, however, those skilled in the art will appreciate that this is one possible shape and should not be considered to limit the scope of the present disclosure. The gas distribution assembly 120 is shown to be trapezoidal, but may be a single circular component or comprised of multiple pie-shaped segments, such as Figure 2 shown.

[0038] Figure 3 The embodiment shown in the embodiment includes a load lock chamber 180 or an auxiliary chamber similar to a buffer station. This chamber 180 is connected to one side of the processing chamber 100 to allow, for example, substrates (also referred to as substrates 60) to be loaded / unloaded from the processing chamber 100. A wafer robot can be positioned in the chamber 180 to move the substrate onto the susceptor.

[0039] The rotation of the turntable (e.g., pedestal assembly 140) may be continuous or discontinuous. In continuous processing, the wafers are constantly rotated so that they are exposed to each injector in turn. In discontinuous processing, the wafers may move to the injector region and stop, and then move to the region 84 between the injectors and stop. For example, the turntable may rotate so that the wafer moves from the region between the injectors through the injectors (or stops near the injectors) and arrives at the region between the next injectors, where the turntable may pause again. The pause between the injectors may provide time for additional processing steps between each layer deposition (e.g., exposure to plasma).

[0040] Figure 4 A sector or portion of the gas distribution assembly 220 is shown, which may be referred to as an injector unit 122. The injector unit 122 may be used alone or in combination with other injector units. Figure 5 As shown, four Figure 4 The injector units 122 are combined to form a single gas distribution assembly 220. (For clarity, the lines separating the four injector units are not shown.) Although in addition to the purge gas port 155 and the vacuum port 145, Figure 4 The injector unit 122 also has both the first reaction gas port 125 and the second reaction gas port 135 , but the injector unit 122 does not require all of these components.

[0041] Reference Figure 4 and Figure 5Both, the gas distribution assembly 220 according to one or more embodiments may include multiple sectors (or injector units 122), where each sector is the same or different. The gas distribution assembly 220 is located within the processing chamber and includes a plurality of elongated gas ports 125, 135, 145 in the front surface 121 of the gas distribution assembly 220. The plurality of elongated gas ports 125, 135, 145 and vacuum ports 155 extend from an area adjacent to the inner peripheral edge 123 toward an area adjacent to the outer peripheral edge 124 of the gas distribution assembly 220. The plurality of gas ports shown include a first reactive gas port 125, a second reactive gas port 135, a vacuum port 145 surrounding each of the first reactive gas port and the second reactive gas port, and a purge gas port 155.

[0042] However, reference Figure 4 or Figure 5 In the embodiment shown in , when it is said that the port extends from at least near the inner peripheral region to at least near the outer peripheral region, the port may not only extend radially from the inner region to the outer region. When the vacuum port 145 surrounds the reaction gas port 125 and the reaction gas port 135, the port may extend tangentially. Figure 4 and Figure 5 In the illustrated embodiment, the wedge-shaped reaction gas ports 125 , 135 are surrounded by vacuum ports 145 on all edges, including adjacent inner and outer peripheral regions.

[0043] See also Figure 4 As the substrate moves along path 127, each portion of the substrate surface is exposed to various reactive gases. Following path 127, the substrate will be exposed to or "see" purge gas port 155, vacuum port 145, first reactive gas port 125, vacuum port 145, purge gas port 155, vacuum port 145, second reactive gas port 135, and vacuum port 145. Therefore, in Figure 4 At the end of the illustrated path 127, the substrate has been exposed to gas flow from the first and second reactive gas ports 125, 135 to form a layer. The illustrated injector unit 122 forms a quarter circle, but may be larger or smaller. Figure 5 The gas distribution assembly 220 shown in FIG. 2 may be considered as four Figure 4 A combination of injector units 122 connected in series.

[0044] Figure 4 The injector unit 122 of FIG. 1 illustrates a gas curtain 150 that separates the reactant gases. The term "gas curtain" is used to describe any combination of gas flow or vacuum that separates the reactant gases from mixing. Figure 4The illustrated gas curtain 150 includes a portion of the vacuum port 145 proximate to the first reactant gas port 125, an intermediate purge gas port 155, and a portion of the vacuum port 145 proximate to the second reactant gas port 135. This combination of gas flow and vacuum can be used to prevent or minimize gas phase reactions of the first reactant gas and the second reactant gas.

[0045] See also Figure 5 The combination of gas flow and vacuum from the gas distribution assembly 220 separates a plurality of processing zones 250. The processing zones are generally defined around each of the reaction gas ports 125, 135, with gas curtains 150 therebetween. Figure 5 The embodiment shown constitutes eight separate processing zones 250 with eight separate gas curtains 150 therebetween. The processing chamber may have at least two processing zones. In some embodiments, there are at least three, four, five, six, seven, eight, nine, 10, 11, or 12 processing zones.

[0046] During processing, the substrate may be exposed to more than one processing region 250 at any given time. However, the portions exposed to different processing regions will have a gas curtain separating the two. For example, if the leading edge of the substrate enters the processing region including the second reactive gas ports 135, the middle portion of the substrate will be located under the gas curtain 150, and the trailing edge of the substrate will be in the processing region including the first reactive gas ports 125.

[0047] A factory interface 280, which may be, for example, a load lock chamber, is shown connected to the processing chamber 100. The substrate 60 is shown superimposed on the gas distribution assembly 220 to provide a frame of reference. The substrate 60 may generally be seated on a pedestal assembly to be held proximate to the front surface 121 of the gas distribution assembly 120 (also referred to as a gas distribution plate). The substrate 60 is loaded into the processing chamber 100 via the factory interface 280, onto a substrate support or pedestal assembly (see Figure 3 ). The substrate 60 is shown as being within the processing region because the substrate is located near the first reactant gas port 125 and between the two gas curtains 150a, 150b. Rotating the substrate 60 along the path 127 will move the substrate counterclockwise around the processing chamber 100. Thus, the substrate 60 will be exposed to the first processing region 250a through the eighth processing region 250h, including all processing regions therebetween. For each cycle around the processing chamber, the substrate 60 will be exposed to four ALD cycles of the first reactant gas and the second reactant gas using the gas distribution assembly shown.

[0048] Conventional ALD sequences in batch processors (e.g. Figure 5ALD process is performed in a spatial ALD batch processing chamber to maintain the flow of chemicals A and B from spatially separated injectors, respectively, with a pump / purge section between the spatially separated injectors. Conventional ALD sequences have start and end patterns that can result in non-uniformity in the deposited film. The inventors surprisingly discovered that a time-based ALD process performed in a spatial ALD batch processing chamber provides a film with higher uniformity. The basic process of exposure to gas A, no reactive gas, gas B, no reactive gas will scan the substrate under the injector to saturate the surface with chemicals A and B, respectively, to avoid the formation of start and end pattern forms in the film. The inventors surprisingly discovered that the time-based approach is particularly beneficial when the target film thickness is thin (e.g., less than 20 ALD cycles), where the start and end patterns have a significant impact on the uniformity characteristics within the wafer. The inventors also discovered that the reaction process (as described herein) to produce SiCN, SiCO and SiCON films cannot be accomplished by time domain processing. The amount of time used to purge the processing chamber causes material to peel off from the substrate surface. The described spatial ALD process does not peel off because the time under the gas curtain is very short.

[0049] Thus, embodiments of the present disclosure relate to processing methods including a processing chamber 100 having a plurality of processing regions 250a-250h, wherein each processing region is separated from adjacent regions by a gas curtain 150. For example, in Figure 5 The processing chamber shown in . Depending on the arrangement of the air flow, the number of air curtains and processing areas in the processing chamber can be any suitable number. Figure 5 The embodiment shown has eight gas curtains 150 and eight processing zones 250a-250h. The number of gas curtains is generally equal to or greater than the number of processing zones. For example, if zone 250a has no reactive gas flow and is used only as a loading zone, the processing chamber will have seven processing zones and eight gas curtains.

[0050] A plurality of substrates 60 are positioned on a substrate support, e.g. Figure 1 and Figure 2 The susceptor assembly 140 is shown in FIG. A plurality of substrates 60 are rotated around the processing region for processing. Typically, a gas curtain 150 is used (gas flowing and vacuum on) throughout the processing, including periods when no reactive gas is flowing into the chamber.

[0051] The first reaction gas A flows into one or more of the processing regions 250, while the inert gas flows into any processing region 250 that does not have the first reaction gas A flowing therein. For example, if the first reaction gas flows into processing region 250b to processing region 250h, the inert gas will flow into processing region 250a. The inert gas may flow through the first reaction gas port 125 or the second reaction gas port 135.

[0052] The inert gas flow within the processing area can be constant or variable. In some embodiments, the reactive gas flows with the inert gas. The inert gas will act as a carrier and diluent. Since the amount of reactive gas is small relative to the carrier gas, the co-flow can more easily balance the gas pressure between the processing areas by reducing the pressure difference between adjacent areas.

[0053] Figure 6 Another embodiment of a gas distribution assembly 120 having four injector units 122 and four openings 610 is illustrated. The openings 610 may be occupied by injector inserts (not shown) that will form a uniform component. In some embodiments, the gas distribution assembly 120 has a temperature controlled body. For example, the large component shown having four openings 610 and four injector units 122 may be cooled and / or heated using fluid channels or other cooling / heating configurations known to those skilled in the art. The openings 610 shown include flanges 612 that are sized to support the injector inserts; however, this is merely representative of one possible configuration and should not be considered to limit the scope of the present disclosure.

[0054] Conventional methods and equipment require a good ground path for the RF current. This precludes the use of a platform that physically moves under multiple CCP electrodes. In this case, a counter electrode is provided, and the return path on the side of the platform where the wafer is placed does not have to be part of the RF return path. This can make it difficult to create a uniform plasma (potential and ion density) across the wafer.

[0055] Some embodiments of the present disclosure advantageously provide apparatus having a pair of capacitively coupled plasma (CCP) sources electrically connected in series. Some embodiments advantageously provide a CCP in which the RF current on one plasma source returns through the other plasma source. Some embodiments advantageously provide apparatus and methods to minimize or eliminate an external ground path through which the RF current returns, making it suitable for mechanically dynamic plasma chambers where it is difficult to ensure a good ground path.

[0056] Some embodiments of the present disclosure advantageously provide apparatus and methods to pair two CCP platforms that move together and use one CCP source as a return route for another source. Some embodiments provide apparatus and methods without complex arrangements for engaging and disconnecting RF return paths.

[0057] In some embodiments, two CCP sources are connected in parallel. The bottom RF paths are connected to each other. RF power is applied to the top side, 180 degrees out of phase with each other, and drives the RF current back and forth in a push-pull manner. The RF current enters one source, leaves the source from the bottom, and returns to the other source from the bottom and leaves the top electrode of the other source.

[0058] The sources can be driven by two RF generators operating 180° asynchronously, or by one generator that will feed both sides via a balun (coaxial transformer, conventional transformer, etc.). The continuity of the RF current through the two sources will allow for improved simultaneous operation of the two sources. Using a single generator can save the cost of a second generator and matching circuits.

[0059] exist Figure 2 and Figure 3 In the embodiment shown in FIG. , the base is a single conductor. In some embodiments, such as Figure 7 As shown, individual substrate supports 710 are used and configured to work like a single wafer pedestal 700. Four individual substrate supports 710 are connected to a cross-shaped pedestal base 720. The pedestal base 720 is connected to a motor 730, which can provide one or more z-axis motions or theta motions (rotations about the z-axis). The wafer pedestal 700 shown has four individual substrate supports 710 and a suitably shaped pedestal base 720; however, the skilled artisan will recognize that there may be any suitable number of substrate supports 710 (e.g., 2, 3, 4, 5, 6, etc.) with a suitably shaped pedestal base 720.

[0060] Each substrate support 710 can be heated / cooled independently of the other substrate supports 710. This allows the wafer on each susceptor to be individually temperature controlled depending on the specific process / reaction occurring at any given location around the z-axis. For example, a processing tool may have four separate processing zones, allowing each wafer to be moved on a susceptor to some or all of the processing zones for multiple reactions and processes.

[0061] Reference Figure 8-Figure 13 One or more embodiments of the present disclosure relate to a processing chamber 800 and method for providing a uniform plasma. Figure 8 In the embodiment shown, a pair of fixed electrodes 820a, 820b and a pair of moving electrodes (illustrated as moving heaters 810a, 810b) can be used in a series circuit as shown. Although the illustrated embodiment uses moving heaters, the present disclosure is not limited to such devices. In general, the present disclosure relates to methods for generating plasma on two or more sources by connecting ground paths and coordinating phases so that physical grounding is not required. In Figure 6 and Figure 7In the embodiment shown in , there may be two or four plasma injectors (showers), two of which may be ignited simultaneously using the phase coordination described herein. A plasma 815a may be ignited between an electrode 820a and a heater 810a, and another plasma 815b may be ignited between an electrode 820b and a heater 810b at the same time. The heaters 810a, 810b may then be moved so that the electrode 820a and the heater 810b are paired, and vice versa. The two plasmas may be ignited again. The same generator 830 and matching set 835 are used to power the two plasmas in series. Without being bound by any particular theory of operation, it is believed that connecting the two plasmas in series ensures that the two plasmas are ignited simultaneously and the same current passes through the two pairs of electrodes, and therefore the two wafers have similar exposures. By alternating between the electrodes and ensuring an average effect for the two wafers. A coaxial cable 840 connects the two heater 810a, 810b electrodes that move with the heaters, so there is no relative motion in the physical RF connection. Reducing the RF components to one generator 830 and one matching set 835 reduces cost and complexity while ensuring wafer-to-wafer consistency.

[0062] exist Figure 8 In the embodiment shown in , a coaxial cable 840 is embedded within the base base 720. The coaxial cable 840 can be connected to the heater and routed in any suitable manner known to a skilled person. The coaxial cable 840 includes an inner conductor 842 and an outer conductor 846 with an insulator 844 between them.

[0063] Fig. 9 A schematic diagram of a processing chamber 900 having substrate supports 910a, 910b and electrodes 920a, 920b is illustrated. An RF source 930 having a suitable matching circuit 935 is coupled to the electrodes 920a and 920b. The substrate supports 910a, 910b (and in some embodiments, a heater) and a coaxial cable 940 form the bottom of the circuit so that current 950 flows in one direction from the RF source 930 back to the RF source 930. The arrow showing the current 950 has a thin line to distinguish between the current 950 and the image current 960. As the skilled person will recognize, the direction of the arrow will change as the RF current oscillates.

[0064] In the illustrated embodiment, the top RF path (connecting 920a to 920b through the RF generator 930) is an open connection. The bottom RF path (connecting support 910a to support 910b) is completed by coaxial cable 940 and connector 970 to form a complete path for image current 960 to flow. The RF source 930 is coupled to the electrode via a transformer-coupled balun. The balun can be used to convert the output of the generator to a balanced output.

[0065] Fig.10 Another embodiment of a processing chamber 1000 is shown. Here, a coaxial line 1040 connects the components of the bottom 1002 (supports 1010a, 1010b), and a coaxial line 1041 connects electrodes 1020a and 1020b through an RF generator 1030. The RF current fed to one plasma source (electrodes 1020a, 1020b) will return via the other source. This will produce an image current 1060, which can cause the RF field in the processing area to be skewed. Using a coaxial path to complete the entire circle can help form a symmetrical current distribution but with a current 1050 (which can be a displacement current or reactive current) along the wall and across the gap 1005 between the top 1001 and the bottom 1002 of the processing chamber 1000. The gap of some embodiments is in the range of about 0.1 mm to about 5 mm, or in the range of about 0.5 mm to about 2 mm, or about 1 mm.

[0066] Fig.11 Another embodiment of a processing chamber 1100 is shown. Fig. 9 , Fig.11 The embodiment shown has a coaxial line 1140 connecting the bottom components (substrate supports 1110a, 1110b), while an open line 1141 connects the top components (electrodes 1120a, 1120b and RF generator 1130). Coaxial lines can also be used to connect the top components. Here, tuning elements 1147a, 1147b are added to bring a virtual ground to the electrodes. It is believed that this will reduce the voltage between the electrodes and the surrounding metal structures 1108 and minimize the chance of initiating discharges in those areas. The tuning elements 1147a, 1147b reduce the voltage between the pedestal (substrate supports 1110a, 1110b) and the surrounding metal structures 1108 to reduce parasitic plasma.

[0067] Fig.12 Another embodiment of a processing chamber 1200 is shown with a dielectric break 1270. The top of the chamber is Fig.11 12. The bottom portion of the chamber differs in that a dielectric breaker 1270 is included. The substrate support 1210a is connected to the substrate support 1210b via a coaxial line 1240 having baluns 1247a, 1247b. The dielectric spacer 1270 separates the substrate supports 1210a, 1210b, thereby reducing image currents in the bottom of the chamber. Without being bound by any particular theory of operation, it is believed that providing a dielectric breaker station eliminates the need for a path along the wall of the chamber. This can result in a voltage difference between the surfaces of the components.

[0068] The dielectric circuit breaker 1270 may be any suitable material known to a skilled person. Suitable dielectric materials include, but are not limited to, quartz, ceramic, and (polytetrafluoroethylene).

[0069] Fig.13 Another embodiment of a processing chamber 1300 having a non-coaxial bottom path is shown. An RF generator 1330 connects electrode 1320a with electrode 1320b. The bottom path is formed without a coaxial line connecting substrate support 1310a with substrate support 1310b. Tuning elements 1347a, 1347b are connected to the outer conductor to provide a return path for the image current without a coaxial line.

[0070] Another embodiment of the present disclosure relates to a processing chamber having at least two plasma stations. As used in this manner, the plasma station has electrodes, showerheads, or gas distribution systems that can be used to generate plasma. The plasma station can be a separate area (e.g., Figure 7-Figure 8 ), or a partitioned portion of a batch processing chamber (such as Figure 1-Figure 6 ).

[0071] See again Figure 8-Figure 13 , the processing chamber 800 includes a wafer pedestal having a plurality of supporting surfaces to support individual wafers for processing. Figure 8 , the support surface is shown as a pair of moving electrodes (shown as moving heaters 810a, 810b).

[0072] Plasma 815a may be ignited between first electrode 820a and first support surface (heater 810a), and plasma 815b may be ignited between second electrode 820b and second support surface (heater 810b) simultaneously. The support surfaces (heaters 810a, 810b) may then be moved so that first electrode 820a and second support surface (heater 810b) are paired, or vice versa. Both plasmas may be ignited again. The same RF generator 830 and matching set 835 are used to power both plasmas in series. RF generator 830 is connected to first electrode 820a in first plasma station and second electrode 820b in second plasma station to form a top RF path. Without being bound by any particular theory of operation, it is believed that having two plasmas in series ensures that both plasmas are ignited simultaneously and the same current passes through both pairs of electrodes, and therefore both wafers have similar exposure. By alternating between electrodes and ensuring an average effect for both wafers. Coaxial cable 840 connects the two heater 810a, 810b electrodes that move with the heaters, so there is no relative motion in the physical RF connection. Reducing the RF components to one generator 830 and one matching set 835 reduces cost and complexity while ensuring wafer-to-wafer consistency.

[0073] exist Figure 8 In the embodiment shown in FIG. 8 , a coaxial cable 840 is embedded within the pedestal base 720. The coaxial cable 840 can be connected to at least two supporting surfaces of the wafer pedestal (e.g., heaters 810a, 810b) to form a bottom RF path. The connection can be routed in any suitable manner known to the skilled person, including (but not limited to) a coaxial (coax) cable. The coaxial cable 840 includes an inner conductor 842 and an outer conductor 846 with an insulator 844 therebetween.

[0074] Figure 9-13 Each of the embodiments shown in the figures is applicable to a processing chamber having at least two support surfaces and at least two plasma stations. The arrangement of components in these figures is analogous to an arrangement of components in which the movable heater is replaced by a more general support surface. The support surface may include a movable heater, but is not limited in this manner.

[0075] Additional embodiments of the present disclosure relate to methods for processing multiple substrates. The method includes powering an RF generator connected to a first electrode in a first plasma processing station and a second electrode in a second plasma processing station to form a top RF path. During powering of the electrodes, a first support surface is located within the first plasma processing station and a second support surface is located in the second plasma processing station. The first support surface and the second support surface are connected to form a bottom RF path. The support surface may be a movable heater or any other pedestal type component known to a skilled person. In some embodiments, the method further includes providing a connector between the first electrode and the second electrode and / or a connector between the first support surface and the second support surface, as described above with reference to Figure 9-13 described.

[0076] In the foregoing description, embodiments of the present disclosure have been described with reference to specific exemplary embodiments of the present disclosure. It will be apparent that various modifications may be made thereto without departing from the broader spirit and scope of the embodiments of the present disclosure as set forth in the claims below. Therefore, the description and drawings should be regarded as illustrative rather than restrictive.

Claims

1. A processing chamber comprising: at least two plasma stations; a wafer pedestal having a plurality of support surfaces to support individual wafers for processing; an RF source connected to a first electrode in the first plasma processing station and a second electrode in the second plasma processing station to form a top RF path; and a connector between a first support surface of the first plasma processing station and a second support surface of the second plasma processing station to form a bottom RF path, Wherein current flows in one direction from the RF source to the first electrode, to the first support surface, through the connection between the first support surface and the second support surface, to the second support surface, to the second electrode, and then back to the RF source.

2. The processing chamber of claim 1, wherein the connection between the first support surface and the second support surface is located within the wafer pedestal.

3. The processing chamber of claim 1, wherein the connection between the first support surface and the second support surface comprises a coaxial connection.

4. The processing chamber of claim 3, further comprising a second bottom RF path connecting the first supporting surface and the second supporting surface.

5. The processing chamber of claim 3, wherein the top RF path is formed via a coaxial cable.

6. The processing chamber of claim 3, further comprising a tuning element coupled to each of the first support surface and the second support surface.

7. The processing chamber of claim 6, wherein the tuning element comprises a balun.

8. The processing chamber of claim 6, wherein the tuning element reduces a voltage difference between the first and second supporting surfaces and surrounding metal structures forming the processing chamber.

9. The processing chamber of claim 3, further comprising a dielectric spacer separating the first supporting surface from the second supporting surface.

10. The processing chamber of claim 9, wherein the dielectric spacer comprises one or more of quartz, ceramic, or polytetrafluoroethylene.

11. The processing chamber of claim 1 , further comprising a tuning element coupled to each of the first support surface and the second support surface.

12. The processing chamber of claim 11, wherein the tuning element comprises a balun.

13. The processing chamber of claim 11, wherein the bottom RF path is formed without a coaxial cable.

14. A processing chamber comprising: a plurality of processing stations arranged around the interior of the processing chamber, the plurality of processing stations including at least two plasma stations; a wafer pedestal having a plurality of heaters to support individual wafers for processing, the number of heaters being equal to the number of processing stations; an RF source connected to a first electrode in the first plasma processing station and a second electrode in the second plasma processing station to form a top RF path; and a connection member between the first heater of the first plasma processing station and the second heater of the second plasma processing station to form a bottom RF path, Wherein current flows in one direction from the RF source to the first electrode, to the first heater, through the connection between the first heater and the second heater, to the second heater, to the second electrode, and then back to the RF source.

15. The processing chamber of claim 14, wherein the connection between the first heater and the second heater is within the wafer pedestal.

16. The processing chamber of claim 14, wherein the connection between the first heater and the second heater comprises a coaxial connection.

17. The processing chamber of claim 16, further comprising a second bottom RF path connecting the first heater to the second heater.

18. The processing chamber of claim 16, further comprising a tuning element coupled to each of the first heater and the second heater.

19. The processing chamber of claim 16, further comprising a dielectric spacer separating the first heater and the second heater.

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