Adjustability of Edge Plasma Density for Tilt Control

Abstract

The plasma lining structure is used in a processing chamber to block a direct line of sight of an internally generated plasma to a ground surface. The plasma lining structure includes a plurality of sections for covering at least one or more portions of an inner surface of a plasma confinement structure disposed in the processing chamber. The sections of the plasma lining structure are positioned between the plasma region and a sidewall of the plasma confinement structure such that the sections face the plasma region when the plasma lining structure and the plasma confinement structure are disposed in the plasma chamber.

Description

Field of the Invention

[0001] The present embodiment relates to a system and apparatus for controlling plasma density on a wafer during etching application. BACKGROUND ART

[0002] Substrates (e.g., wafers, flat panels) are subjected to various types of processing to form electronic devices such as integrated circuits and thin display devices. The substrate is placed in a processing chamber and undergoes different processing operations (plasma etching, cleaning, deposition, etc.) that expose the surface of the substrate to different chemicals. For example, during a plasma etching operation, a selected portion of the substrate surface is exposed to plasma. This portion is selectively exposed by placing a photoresist mask layer on the substrate surface and exposing the substrate to plasma etching so that the plasma etching can remove the underlying material not covered by the photoresist.

[0003] Etching has conventionally been performed mainly to develop planar (i.e., two-dimensional) devices (e.g., memory devices) in which a single memory cell is defined. To reduce the manufacturing cost of these devices, manufacturers have attempted to adjust the dimensions of planar devices by reducing the size of the memory cells. However, adjusting the dimensions of planar devices to achieve high density has its own problems due to cell-to-cell interference, thereby reducing the reliability of such planar devices. To maximize the limited physical space on the wafer, minimize the manufacturing cost of the device, and provide a reliable device, three-dimensional (3D) devices have been developed. In a 3D NAND device, for example, memory cells are stacked in multiple layers, thereby allowing more devices to be defined on the wafer. The advantage of 3D devices is that the memory cells are enlarged by vertical stacking, increasing the storage capacity and enhancing the reliability.

[0004] However, the application of dielectric etching used to generate 3D devices has its own challenges. For example, simultaneously controlling local and global slopes is a major challenge. As the aspect ratio increases, the slope specifications are becoming increasingly stringent. Global slope control is used to focus the process on a method with the best slope across the entire wafer. Local slope control is used to fine-tune the slopes in different regions, including the central region, intermediate region, edge region, and extreme edge region on the wafer surface. Currently available local slope control techniques are insufficient to meet the slope specifications across different regions of the wafer surface. In particular, it is very difficult to independently control the slope specifications in the wafer edge region of the wafer. Various techniques have been tried to independently control the local slope and have achieved some success. Furthermore, these techniques present additional challenges. For example, changing the RF frequency for generating plasma and adjusting the design of the upper electrode, especially a part of the upper electrode covering the wafer edge region, have been tried but have had little success, and these techniques have brought various levels of challenges. Other techniques such as changing the plasma volume, changing the coupling to the ground ring, and increasing the upper electrode resistance have also been attempted to control the local slope at the wafer edge, but each of these techniques has its own challenges.

[0005] The embodiments described in this disclosure have arisen against such a background.

Summary of the Invention

[0006] To control the tilt of 3D devices formed on a wafer by the application of etching (such as the application of high aspect ratio (HAR) three-dimensional (3D) etching), a system, apparatus, and method for adjusting the edge plasma density are presented. This adjustment enables the simultaneous control of the global and local tilt of the 3D device. Global tilt control allows the process to be focused on a method with the best tilt across the entire wafer, and local tilt control enables fine-tuning of the tilt in various regions such as the central region, intermediate region, edge region, and extreme edge region of the wafer. The application of etching is carried out in a processing chamber having a plasma confinement structure (such as a C-shroud), and the plasma confinement structure confines the plasma within the plasma region defined in the processing chamber. The plasma lining structure is provided to block the line of sight to at least a part of the inner surface of the side wall of the plasma confinement structure for the wafer region plasma, thereby blocking the path of the plasma to ground.

[0007] The plasma lining structure protects the ground return path of the plasma while blocking the horizontal line of sight to the side wall of the plasma confinement structure. The ground return path is defined along the upper electrode (inner upper electrode and outer upper electrode) through the plasma confinement structure to the ground ring. By eliminating the horizontal line of sight to the large ground plane (i.e., the side wall) of the plasma confinement structure, the plasma density is significantly suppressed within the plasma region, particularly along the edge region of the wafer. Such suppression of the plasma density in the edge region results in a local improvement in the uniformity of the etching rate in the edge region, thereby improving the tilt shape in the edge region of the wafer.

[0008] Various embodiments can be provided. In one embodiment, a plasma confinement structure is provided that has a plasma lining structure to cover at least a part of the inner surface of its sidewall. In this embodiment, the plasma confinement structure may be a C-shroud. The plasma lining structure may be made of quartz or any other dielectric material. A change in the area of the plasma confinement structure covered by the plasma lining structure may also be provided. For example, only the inner surface of the sidewall of the plasma confinement structure may be covered by the plasma lining structure. In another example, the entire inner surface of the plasma confinement structure exposed to the plasma may be covered by the plasma lining structure. In yet another example, only the inner surface of the sidewall and the back surface of the top of the plasma confinement structure may be covered by the plasma lining structure. In another example, only the inner surface of the sidewall and the upper surface of the bottom of the plasma confinement structure may be covered by the plasma lining structure.

[0009] In another embodiment, a plasma confinement structure of a different structure may be implemented. For example, the plasma confinement structure may be an E-shroud having a plurality of annular protrusions defined along the inner sidewall, rather than a C-shroud. In this example, the plasma lining structure (e.g., a quartz member) may be disposed in the space between a pair of adjacent annular protrusions of the E-shroud and between the annular protrusions of the E-shroud and the upper and / or bottom sections, so as to sufficiently prevent access to the sidewall of the E-shroud. In another embodiment, the plasma lining structure may be used to cover the inner surface of the E-shroud, including the surfaces of the annular protrusions of the E-shroud and the sidewalls between the annular protrusions. The thickness of the plasma lining structure may be defined so as to sufficiently block the view of the plasma to the grounded sidewall of the plasma confinement structure. The plasma lining structure may be composed of two or more sections. In some embodiments, each of the two or more sections is configured to form a ring that substantially covers the entire inner surface of the sidewall of the plasma confinement structure. In such embodiments, each section may be securely connected to an adjacent section. Alternatively, adjacent sections may be configured to define a gap therebetween. Each section may be coupled to different portions of the plasma confinement structure so that it can be repeatedly mounted in a clear orientation.

[0010] After generally understanding these features, specific embodiments will be described below.

[0011] According to one embodiment, a plasma lining structure for use with a plasma confinement structure having an annular vertical sidewall is disclosed. The sidewall has an inner surface. The plasma lining structure includes a plurality of sections configured to conform to and cover at least one or more portions of the inner surface of the sidewall. The plurality of sections are configured to be positioned between the plasma region of the processing chamber and the sidewall when the plasma lining structure and the plasma confinement structure are disposed in the processing chamber. The plurality of sections of the plasma lining structure are arranged to face the plasma region.

[0012] According to another embodiment, a plasma confinement structure used in a processing chamber is disclosed for confining plasma generated within a region defined between an upper electrode and a lower electrode therein. The plasma confinement structure includes an annular vertical sidewall. The sidewall has an inner surface. The plasma lining structure includes a plurality of sections configured to conform to and cover at least one or more portions of the inner surface. The plurality of sections are configured to be located between the plasma region and the sidewall so as to face the plasma region when the plasma confinement structure and the plasma lining structure are disposed within the processing chamber. The plurality of sections are arranged to face the plasma region.

[0013] In yet another embodiment, a processing chamber used for confining plasma generated within the plasma region therein is disclosed. The processing chamber includes an upper electrode disposed at the upper part. The upper electrode is connected to a gas source and configured to provide gas from the gas source to the processing chamber and is electrically grounded. The processing chamber also includes a lower electrode disposed at its bottom. The lower electrode is directed towards the opposite side of the upper electrode and defines a plasma region located therebetween. The lower electrode includes a support surface for receiving a wafer and is connected to a plurality of radio frequency (RF) power sources through a corresponding matching network. The plasma confinement structure is defined between the upper electrode and the lower electrode and is configured to confine plasma within the plasma region. The plasma confinement structure includes an annular vertical sidewall. The sidewall has an inner surface. The plasma lining structure includes a plurality of sections configured to conform to and cover at least one or more portions of the inner surface. The plurality of sections are configured to be located between the plasma region and the sidewall so as to face the plasma region when the plasma confinement structure and the plasma lining structure are disposed within the processing chamber.

[0014] Other aspects will become apparent from the following description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0015] The embodiments will be fully understood with reference to the following description, which is described in conjunction with the accompanying drawings.

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DETAILED DESCRIPTION OF THE INVENTION

[0026] Embodiments present a system, apparatus, and method for adjusting plasma density along the edge of a wafer received in a processing chamber. This adjustment enables control of the tilt shape of three-dimensional (3D) devices defined on the surface of the wafer. The processing chamber may be a plasma etching chamber in which plasma is confined in a plasma region defined between its upper and lower electrodes. A plasma confinement structure, such as a C-shroud, is disposed between the upper and lower electrodes and is used to confine the plasma generated in the plasma chamber to the plasma region. The plasma lining structure is provided to cover at least the inner surface of the sidewalls of the plasma confinement structure disposed in the plasma chamber. The plasma lining structure helps to simultaneously control the global tilt and the local tilt in order to improve the tilt shape of the 3D devices defined on the surface of the wafer. Control of the global tilt enables focusing the process on a method that provides the best tilt across the entire wafer surface. Control of the local tilt enables fine-tuning the tilt of different regions including the central region, the intermediate region, the edge region, and the extreme edge region of the wafer. The plasma lining structure enables control of the local tilt by blocking the line-of-sight of the plasma generated in the plasma region to the grounded sidewalls of the plasma confinement structure. However, the plasma lining structure protects the ground return path defined from the plasma confinement structure to the ground ring through the upper electrode. By blocking the line-of-sight of the plasma to the large ground plane (i.e., the extensive sidewalls) of the plasma confinement structure, the density of the plasma in the plasma confinement structure is significantly suppressed, especially at the edge of the wafer. The suppression of the plasma density results in a local improvement in the uniformity of the etching rate in the edge region and an improvement in the tilt shape of the 3D devices defined on the wafer. The plasma lining structure is composed of a plurality of sections adapted to and disposed to cover at least one or more portions of the inner surface of the sidewalls of the plasma confinement structure. Additional fine-tuning can be achieved by providing windows in the plasma lining structure or by controlling the gaps between each pair of adjacent sections of the plasma lining structure.The size of the window or gap may be defined based on the amount of fine-tuning required. Control of the local tilt is not limited to the wafer edge region and can also be performed in other regions such as the central region, intermediate region, and extreme edge region of the wafer.

[0027] In some methods of etching using a plasma confinement structure such as a C-shroud, controlling the local tilt is challenging. Also, due to the increase in aspect ratio and density, the tilt specifications are becoming increasingly stringent. Global tilt control can be provided by focusing on the process for defining the best tilt across the entire wafer. However, local tilt control, which is used to control specific attributes of the processing chamber (provided in the form of dynamic "knobs"), may not provide sufficient local tilt control. Examples of attributes that can be controlled include the gap in the processing region, the flow rate of the processing gas, the frequency used for plasma generation, etc. Adjustment of "static" chamber-related attributes showed only a slight improvement in local tilt performance, especially in the edge region and extreme edge region of the wafer. Some static chamber-related attributes include the structure / shape such as the internal electrode, external electrode, edge kit used in the processing chamber, connector to the ground ring, and upper electrode resistivity. In addition to chamber-related attributes, adjustment to process recipe-related attributes (such as the plasma volume in the plasma confinement structure (e.g., C-shroud)) showed only a slight improvement in local tilt performance, especially in the edge region and extreme edge region of the wafer. Adjusting different attributes separately, such as adjusting the frequency of the RF power (e.g., adjusting a 60 megahertz RF power source), has been shown to provide improvement in global tilt control but only slight local tilt control.

[0028] The plasma lining structure introduced between the sidewall of the plasma confinement structure and the plasma region serves to provide an improvement in the control of local gradients by blocking the horizontal line of sight (line of sight) of the plasma to ground. The plasma lining structure suppresses the plasma density, particularly at the wafer edge, in the plasma region defined inside the plasma confinement structure. The plasma lining structure comprises two or more sections, and each pair of adjacent sections is connected to each other at a connecting interface. Additionally, the plasma lining structure may be connected or coupled to different parts of the plasma confinement structure using alignment pins, fixing pins, or bonding surfaces. The connection of the different sections of the plasma lining structure allows for a clear and repeatable orientation when assembled in the processing chamber. An individual plasma lining structure is one way to block the direct line of sight of the plasma. Other ways of blocking the line of sight can also be provided, such as a hybrid plasma confinement structure having a plasma lining structure coupled to the sidewall of the plasma confinement structure. The plasma lining structure may be made of quartz or any other dielectric material.

[0029] Having generally understood the embodiments of the invention, exemplary details of various embodiments will now be described with reference to the various drawings here. It will be apparent that these embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations are not described in detail so as not to make these embodiments needlessly difficult to understand.

[0030] FIG. 1 depicts a processing module 100 configured to perform plasma etching on a wafer surface. In one embodiment, the processing module 100 may be a capacitively coupled plasma processing system. The capacitively coupled plasma processing system may include, in addition to other hardware (e.g., a computer / controller, etc.), a processing chamber (or simply referred to as a "chamber") 106 for generating plasma. Accordingly, the chamber 106 may be a capacitively coupled dielectric chamber and includes an upper electrode 110 such as a showerhead, and a lower electrode (i.e., a wafer support module) 104 such as a pedestal or an electrostatic chuck (ESC). In the embodiment shown in FIG. 1, the showerhead 110 is shown in a grounded state, and the wafer support module 104 is coupled to a plurality of RF power supplies 124a - 124d. In another embodiment, the showerhead 110 may be biased, or coupled to a second RF power supply (not shown), and powered. In one embodiment, the showerhead 110 may include an inner showerhead 110a and outer showerheads 110b disposed on both sides of the inner showerhead 110a. For example, the outer showerhead 110b may be used to expand the plasma region beyond the edge of the wafer received by the wafer support module 104. The showerhead 110 is connected to one or more gas sources 128, and the one or more gas sources 128 are then coupled to a controller 122. The controller 122 generates signals to cause the RF power supplies 124a - 124d to provide RF signals for powering the wafer support module 104, and cause the gas sources 128 to inject a desired process gas into the plasma region 120 of the chamber 106 for generating plasma. The desired process gas may be based on a process recipe used in the chamber 106 controlled by the controller 122. The plasma is generated in the plasma region 120 defined between the upper electrode (i.e., the showerhead) 110 and the lower electrode (wafer support module) 104 using the process gas injected into the chamber 106 and the RF power provided by the RF power supplies 124a - 124d.Plasma may be used to etch the surface of the wafer or to volatilize deposits formed on different surfaces of chamber 106.

[0031] Edge ring 132 is disposed on wafer support module 104 so as to be adjacent to the wafer when wafer 102 is received by wafer support module 104. The chamber sidewall extends along the lateral length of chamber 106. An access window (not shown) defined along the chamber sidewall of chamber 106 is used to load and unload the wafer with respect to chamber 106. A plasma confinement structure 140, such as a C-shroud, is defined between upper electrode 110 and lower electrode (i.e., wafer support module) 104 and is used to confine plasma within plasma region 120. C-shroud 140 includes vertical portions representing an upper portion, a bottom portion, and sidewalls. The sidewalls extend between a first end at the upper portion and a first end at the bottom portion. A second end at the upper portion is coupled to the bottom surface of upper electrode 110, and a second end at the bottom of the C-shroud is coupled to ground ring 133. In some embodiments, ground ring 133 may be connected to the bottom of the C-shroud via a flexible conductive strap.

[0032] RF power supplies 124a - 124d may be configured to supply RF power at different frequencies to power the lower electrode in order to generate plasma. In some embodiments, the RF power can be supplied at 400 kilohertz (KHz), 2 megahertz (MHz), 27 MHz, and / or 60 MHz, or combinations thereof. Of course, these frequencies are provided as examples, and other frequencies with conductive power may be used to generate plasma. The RF power is provided to chamber 106 through corresponding matching networks 125a and 125b. The plasma generated by the RF power attempts to find the path of least resistance to ground. High-frequency RF signals (such as frequency signals of 2 MHz, 27 MHz, and 60 MHz) take the shortest path to ground by passing through the upper electrodes (110a and 110b), down the sidewalls of the C-shroud 140, and through the ground ring 133 as shown by the dashed line 103. In some cases, a portion of the high-frequency RF plasma may follow a horizontal "line-of-sight" path to the sidewalls of the C-shroud 140. For low-frequency RF signals such as the 400 KHz signal, most of the RF plasma follows a horizontal line-of-sight towards the sidewalls of the C-shroud 140 as shown by the dashed line 107. The sidewalls provide a large ground plane for most of the plasma, but a portion of the plasma passes through the upper electrode and another portion of the plasma escapes through slots defined at the bottom of the C-shroud 140. The horizontal path taken by the RF plasma causes an increase in plasma density along the edge of the wafer, resulting in significant gradients in the devices formed on the wafer, especially those formed at the edge and extreme edge of the wafer. The gradients in the devices affect the gradient specifications across the entire wafer surface.

[0033] To control the tilt and meet the tilt specifications of the wafer, a plasma lining structure is inserted along at least the inner surface of the sidewalls of the plasma confinement structure (i.e., the C-shroud) 140, blocking the view of the plasma to ground. The plasma lining structure is made of quartz in one embodiment. In another embodiment, the plasma lining structure is coated with a dielectric material. The plasma lining structure significantly suppresses the plasma density inside the C-shroud 140, particularly at the wafer edge. This modification of the plasma density locally improves the uniformity of the etching rate along the wafer edge region, subsequently improving the tilt shape of the wafer edge region.

[0034] The plasma lining structure provides better local tilt control than that provided by conventional dynamic "knobs" or settings designed to adjust attributes of the processing chamber or process recipe-related attributes. Independent adjustment of the frequency of the RF power achieved excellent global tilt control but had little effect on local tilt control. On the other hand, the plasma lining structure provided improved local tilt control not only at the wafer edge but also in other regions of the wafer.

[0035] The pump 126 is coupled to the chamber 106 to exhaust the process gas and / or by-products generated during the etching operation from the chamber 106. The pump 126 is coupled to the controller 122 to control its function.

[0036] The controller 122 includes a processor, memory, integrated circuits, software logic, hardware logic, and an input / output subsystem. The controller is configured to receive instructions, transmit signals / instructions, enable endpoint measurements, communicate with various components of the chamber 106, and monitor and control various aspects of the etching operation performed within the chamber 106. The controller 122 may be part of a substrate processing system, such as a cluster tool, that includes a plurality of chambers including the chamber 106. As a result, the controller 122 may be coupled to each chamber within the cluster tool to individually communicate, monitor, and control various aspects of the process operations performed within each chamber of the cluster tool. The controller 122 includes one or more recipes that include a plurality of setpoints for various operating parameters of different processes performed within different chambers of the cluster tool. The various operating parameters may correspond to voltage, current, frequency, pressure, flow rate, power, temperature, and the like. The controller may be programmed to control various process operations depending on the processing requirements and / or the type of system. Some of the process operations include the supply of process gases, temperature setting (e.g., heating and / or cooling), pressure setting, vacuum setting, power setting, setting of a radio frequency (RF) generator, setting of an RF matching circuit, frequency setting, flow rate setting, fluid supply setting, position movement setting, and setting of wafer loading / unloading to a load lock connected or coupled to a chamber and other transfer modules and / or specific modules of the cluster tool.

[0037] The integrated circuit of the controller 122 may include a chip in the form of firmware that stores program instructions, a digital signal processor (DSP), a chip defined as an application-specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). The program instructions are instructions transmitted to the controller in the form of various individual settings (or program files), and may define operating parameters for performing a specific process (such as an etching operation) on or for a semiconductor wafer or on the system. In some embodiments, the operating parameters may be part of a recipe defined by a process engineer to implement one or more processing steps. The processing steps may include the formation of layers on the surface of the wafer, the removal of layers, and the deposition of materials (such as metals, oxides, silicon, silicon dioxide, etc.) during the manufacture of one or more circuits and / or dies on the wafer.

[0038] In some embodiments, the controller may be part of a computer integrated with or network-connected to the system, or may be coupled to the computer. For example, the controller may be within a "cloud" that enables remote access and control of the processing operations of a cluster tool (i.e., a substrate processing system) for defining circuits on a wafer, or may be all or part of a fab host computer system. The computer may enable remote access to the system to monitor the progress of current manufacturing operations. The computer may also investigate the history of past manufacturing operations, investigate trends or performance criteria from multiple manufacturing operations, to change the parameters of the current process, or to set the processing steps following the current process, or to initiate a new process. In some examples, a remote computer (e.g., a server) can provide a process recipe to the system through a network including a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings transmitted from the remote computer to the system. In some examples, the controller receives in the form of data instructions that specify the parameters of each of the processing steps performed during one or more process operations. It should be understood that the parameters may be specific to the type of process being performed and the type of cluster tool or process module that the controller is configured to connect to or control. The controller may be distributed, for example, by comprising one or more separate controllers network-connected to each other and cooperating towards a common purpose such as the processes and controls described herein. An example of such a distributed controller for such a purpose would be one or more integrated circuits on chamber 106 that are located remotely (e.g., at the platform level or as part of a remote computer) and communicate with one or more integrated circuits that cooperate to control the process in chamber 106.

[0039] In addition to the process module 100 for etching a wafer, the substrate processing system may include, without limitation, a deposition chamber or deposition module, a spin rinse chamber or spin rinse module, a metal plating chamber or metal plating module, a cleaning chamber or cleaning module, a bevel edge etching chamber or bevel edge etching module, a physical vapor deposition (PVD) chamber or PVD module, a chemical vapor deposition (CVD) chamber or CVD module, an atomic layer deposition (ALD) chamber or ALD module, an atomic layer etching (ALE) chamber or ALE module, an ion implantation chamber or ion implantation module, a track chamber or track module, or any other semiconductor processing system that may be relevant or used in the fabrication and / or manufacture of semiconductor wafers.

[0040] As described above, the controller may communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools installed throughout the manufacturing facility, tools within the factory, the main computer, another controller, or tools used for material transport for loading and unloading wafer containers with respect to tool positions and / or load ports in semiconductor manufacturing facilities.

[0041] Figures 2A and 2B represent cross-sectional views identifying various components of a plasma confinement structure (such as C-shroud 140) having a plasma lining structure 150, and the plasma lining structure 150 is disposed between the sidewall of the plasma confinement structure (i.e., C-shroud) 140 and the plasma region 120. The plasma lining structure 150 is used to provide control of local inclination. The C-shroud 140 shown in FIGS. 2A and 2B is a circular structure surrounding the plasma region 120 to substantially confine the plasma generated within the chamber 106 to the plasma region 120. The C-shroud 140 includes an upper portion 141, a bottom portion 143, and vertical portions respectively represented by sidewalls 142 extending between a first end of the upper portion 141 of the C-shroud 140 and the bottom portion 143. In one embodiment, the bottom portion 143 of the C-shroud 140 includes a downward extension at a second end. The downward extension is connected to a ground ring 133 defined on a lower electrode of the chamber 106 via a flexible conductive strap. A plurality of slots 145 are defined along the bottom portion 143 of the C-shroud 140. The slots 145 are sized to provide an unobstructed path for plasma and by-products to escape from the plasma region 120. In some embodiments, the width "w1" of each slot 145 is defined from about 1.5 mm to about 3 mm. In some embodiments, the outer height "h1" of the sidewall 142 of the C-shroud is defined from about 1 inch (2.54 centimeters) to about 3 inches (7.62 centimeters). It should be understood that the outer height h1 of the sidewall 142 of the plasma confinement structure (e.g., C-shroud) 140 may vary from one chamber 106 to another and may sometimes depend on the type of process being performed within the chamber 106. Similarly, the width w1 may be defined based on the type of process gas used in the processing chamber.

[0042] Figure 2A shows a portion of a plasma confinement structure (e.g., a C-shroud) 140 that includes a plasma lining structure 150. The plasma lining structure 150 is provided to line at least the inner surface of the side wall 142 of the plasma confinement structure 140 (i.e., the C-shroud), and is positioned between the side wall 142 of the C-shroud 140 and the plasma region 120 such that the inner surface of the plasma lining structure 150 faces the plasma region 120. The side wall 142 has an annular shape. The plasma lining structure 150 is composed of a plurality of sections that conform to and cover one or more portions of the inner surface of the side wall 142 of the C-shroud. In some embodiments, the plurality of sections includes two or more arcuate sections, and the arcuate shape conforms to the circular shape of the C-shroud 140. The plurality of sections of the circular plasma lining structure 150 extend such that their height lines the inner surface of the vertical side wall 142. In one embodiment, two or more arcuate sections of the plasma lining structure 150 form a continuous ring that completely covers the entire side wall 142 of the C-shroud 140. Since the shape of the C-shroud 140 is such that the inner diameter of its side wall 142 is larger than the inner diameters of both its upper portion 141 and its bottom portion 143, two or more sections of the plasma lining structure 150 are attached inside the chamber 106 so as to line the inner surface of the side wall 142.

[0043] In some embodiments, a pair of adjacent arcuate sections are designed to connect to each other to form a connecting interface 152. Additionally, each arcuate section may be coupled to the bottom 143, top 141, or sidewall 142 of the C-shroud 140 using a coupling mechanism or a connecting mechanism (e.g., a fixed pin, an alignment pin, or a mating extension defined in each section of the C-shroud 140). The coupling mechanism is not limited to a mating extension, an alignment pin, or a fixed pin and can be expanded to include other types / forms of connectors. The connecting and / or coupling mechanism enables the pair of adjacent sections of the plasma lining structure to be aligned with the slots of the C-shroud 140. Additionally, two or more sections are fixed to each other and to the C-shroud to ensure that each section is received in a specific position and orientation so that each section can be repeatedly mounted in a clear orientation.

[0044] In some embodiments, the plasma lining structure 150 is made of quartz to reduce RF coupling. The material used for the plasma lining structure 150 is not limited to quartz, and any other material having the same or similar thermal and conductive properties as quartz can be used. For example, the plasma lining structure 150 may be made of a dielectric material. A dielectric material is a non-metallic heat insulator. In the embodiment shown in FIG. 2A, the C-shroud 140 is made of silicon. The plasma lining structure 150 is arranged such that two or more sections face the plasma region 120. As a result, the plasma lining structure 150 is a consumable part as it is constantly exposed to plasma within the chamber 106.

[0045] Figure 2B shows another embodiment of a plasma lining structure 150' used to line the inner surface of the sidewall 142 of the C shroud 140. The plasma lining structure is composed of a plurality of sections, and each section has a plurality of segments. The plurality of segments may include vertical segments configured to cover the vertical portion 142 of the C shroud 140, upper segments configured to cover the back surface of the upper portion 141 of the C shroud 140, and bottom segments configured to cover the upper surface of the bottom 143 of the C shroud 140. The bottom segment may include a plurality of liner slots that align with a plurality of slots defined at the bottom of the C shroud 140 when the plasma lining structure 150' is installed in the processing chamber. In this embodiment, each section of the plasma lining structure 150' includes one or more windows 155 defined along the vertical segment. The windows 155 provide a direct path to ground for the RF plasma by exposing the corresponding portion of the sidewall 142 of the C shroud that aligns with the windows 155 to the plasma. The windows 155 are sized to expose a desired amount of the ground plane of the sidewall 142 to the plasma. In some embodiments, the number and position of the windows 155 are determined by the level of adjustment performed in different regions of the wafer so as to have an optimal plasma density in different regions of the wafer.

[0046] Figures 3A and 3B provide a top perspective view of a C-shroud 140 comprising a plasma lining structure 150 defined to line the inner surface of sidewall 142 in some exemplary embodiments. The plasma lining structure 150 comprises two or more sections arranged to conform to or fit the shape of the plasma confinement structure 140. In one embodiment, the plasma confinement structure (e.g., C-shroud) 140 is annular, and the plurality of sections of the plasma lining structure 150 are arranged to form a complete circle covering the entire sidewall 142 of the C-shroud 140. Since the inner diameter of the sidewall of the C-shroud 140 is larger than the radii of the upper (141) and lower (143) portions of the plasma confinement structure (e.g., C-shroud) 140, two or more sections of the plasma lining structure 150 are received and attached inside the processing chamber. In the example of FIG. 3A, the plasma lining structure 150 is composed of four sections (sections 1-4). Each section is coupled to an adjacent section at a connecting interface. For example, each of the four sections may comprise a lip (i.e., an extension (also referred to as a "tab")) that securely fits into a complementary recess or indentation of an adjacent section to form a connecting interface 152. For example, section 1 may have a lip or extension 156 defined along the outer diameter portion. Adjacent element section 2 may have a complementary recess or indentation 153 defined in the inner diameter portion, and the lip 156 defined at the first end of section 1 may be coupled to the complementary recess 153 defined at the first end of section 2 to form the connecting interface 152. Similarly, the lip 156 defined at the second end of section 1 may be coupled to the complementary recess 153 of section 3. In this example, sections 2 and 3 are shown to have similar cross-sectional shapes and are arranged opposite each other. Sections 1 and 4 are shown to have similar cross-sectional shapes and are arranged opposite each other. Further, section 1 is adjacent to the first ends of sections 2 and 3, and section 4 is adjacent to the second ends of sections 2 and 3.The number of sections of the plasma lining structure 150 is provided as a mere example, and it should be noted that fewer or more sections may be used to line the inner surface of the side wall 142 of the C shroud 140. In some embodiments where lips and recesses are used to define the connection interface surface, the number of sections may be even so that the lip of one section can engage with the complementary recess of an adjacent section.

[0047] FIG. 3B depicts another embodiment in which the plasma lining structure 150 comprises three sections (sections 1-3) distributed to cover the inner surface of the side wall 142 of the C shroud 140. In this embodiment, the sections are of uniform size, and each section is spaced from an adjacent section to define a gap of a particular width. Since the size of each section is small, it is easy to attach the sections to line the inner surface of the C shroud 140 without the need for a connection interface surface. As a result, no connection interface surface is shown in FIG. 3B. Similar to the embodiment where the plasma lining structure 150 includes a window (i.e., the embodiment shown in FIG. 2B), the gap between two adjacent or neighboring sections exposes a portion of the side wall 142 of the C shroud 140 to the plasma, thereby providing a direct path for the plasma to ground. The number and size of the sections, as well as the size of the gap, are defined such that while the majority of the grounded side wall 142 of the plasma confinement structure 140 blocks the path of the plasma to ground, some exposure to the plasma is provided to the grounded side wall 142. In FIG. 3B, the gap between a pair of adjacent or neighboring sections is shown significantly enlarged to illustrate the presence of the gap. In reality, the gap may be much narrower so that only a very small portion of the side wall 142 of the plasma confinement structure 140 is exposed to the plasma. Further, the number of sections is provided as a mere example, and fewer or more sections may be used to line the inner surface of the side wall of the C shroud 140.

[0048] Figures 4A - 4D show various configurations of a plasma lining structure 150 that can be arranged to line the inner surface of a plasma confinement structure (such as the C - shroud 140). The plasma confinement structure 140 includes a vertical portion represented by an upper part 141, a bottom part 143, and side walls 142 extending from a first end of the upper part 141 to a first end of the bottom part 143. The second end of the upper part 141 is coupled to the side wall of the upper electrode, and the second end of the bottom part 143 is coupled to the ground ring. In each configuration, the plasma lining structure 150 is installed in the chamber 106 so as to completely cover at least the inner surface of the side walls 142 of the C - shroud 140, or comprises two or more sections that include a gap between a pair of adjacent sections. Each section of the plasma lining structure 150 is arcuate so as to match or conform to the shape of the C - shroud 140, which is circular in one embodiment. Each section may comprise a plurality of segments including vertical segments extending for height. The height of the vertical segments is based on the inner height of the side walls 142 of the C - shroud 140 such that when the section is installed in the chamber 106, each section substantially covers a part of the side wall of the C - shroud 140 where it is located. The inner surface of the plasma lining structure 150 is a consumable part with a limited lifespan because it is always exposed to plasma in the chamber 106 depending on its position in the chamber 106. After reaching the end of its lifespan, the existing plasma lining structure 150 is discarded and a new plasma lining structure 150 is installed at a predetermined position within the C - shroud 140.

[0049] Figure 4A shows an embodiment in which the plasma lining structure 150 comprises only vertical segments that cover the entire inner surface of the side walls 142 of the C - shroud 140. This is similar to the embodiments described with reference to Figures 2A - 2B and Figures 3A - 3B. The height of the vertical segments of the plasma lining structure 150 is configured to be less than the inner height of the side walls of the C - shroud 140 such that a gap is defined between the upper surface of the plasma lining structure 150 and the back surface of the upper part 141 of the C - shroud 140, and this gap is small enough and sufficient to enable the installation and attachment of the plasma lining structure 150 within the chamber 106.

[0050] Figure 4B shows another embodiment in which the plasma lining structure 150 covers the entire inner surface of a plasma confinement structure (i.e., a C-shroud) 140 that includes the back surface of the upper portion 141, the side walls 142, and the upper surface of the bottom portion 143. The plasma confinement structure 140 is in an annular shape. The plasma lining structure 150 is composed of two or more sections so that it can be easily attached to cover the inner surface of the C-shroud 140. For example, as shown in FIG. 3A, the plasma lining structure 150 may be composed of four sections (sections 1 to 4) arranged to conform to the annular shape of the plasma confinement structure so as to form a complete circle, and each section covers a part of the inner surface of the plasma confinement structure 140. Alternatively, as shown in FIG. 3B, the plasma lining structure 150 may be composed of sections 1 to 3 arranged along the annular shape of the plasma confinement structure 140 having a gap defined between any pair of adjacent sections, and each section covers a part of the inner surface of the plasma confinement structure 140. Each section may include a plurality of segments. In the example shown in FIG. 4B, each section is composed of two segments: a first segment 150a that covers both the back surface of the upper portion 141 and the inner surface of the side wall 142 of the C-shroud 140, and a second segment 150b that covers the upper surface of the bottom portion 143 and a downward extension that connects the C-shroud 140 to the ground ring 133. Each segment is coupled to the corresponding surface of the C-shroud 140 using a coupling mechanism that may include a fitting extension and a fixing pin. In this embodiment, the second segment 150b includes a plurality of liner slots that are aligned with corresponding slots defined in the bottom portion 143 of the C-shroud 140.

[0051] In another embodiment (not shown), each section may comprise three segments: an upper segment covering the back surface of the upper portion 141 of the C shroud 140, a vertical segment covering the inner surface of the side wall (i.e., the vertical portion) 142, and a bottom section covering the upper surface and the downward extension of the bottom 143 of the C shroud 140. The bottom section includes a plurality of liner slots that are aligned with corresponding slots in the bottom 143 of the C shroud 140. The number of sections and the number of segments in each section are shown by way of example, and fewer or more sections and segments may be provided. Fixing pins, mating pins, or mating extensions may be used to fix the sections / segments to each other and to the corresponding surfaces of the C shroud 140.

[0052] Figure 4C represents another configuration in which the plasma lining structure 150 is designed to cover only the back surface of the upper portion 141 and the inner surface of the side wall 142 of the C shroud 140. In this configuration, each section of the plasma lining structure 150 is composed of two segments. The first segment 151 covers the back surface of the upper portion 141 of the C shroud 140, and the second segment 154 covers the inner surface of the side wall 142. In the configuration shown in Figure 4C, each segment is defined to cover a specific planar portion of the C shroud 140. For example, the first segment 151 covers the horizontal portion of the C shroud 140, and the second segment 154 covers the vertical side wall of the C shroud 140. The embodiments are not limited to the configuration of Figure 4C and may include additional segments for the second segment 154 that covers the inner surface of the side wall 142. For example, the second segment 154 may include a first sub-segment and a second sub-segment that are joined to form a connecting interface surface.

[0053] FIG. 4D shows a different configuration where the plasma lining structure 150 is designed to cover only the upper surface of the bottom 143 of the C-shroud 140 and the inner surface of the side wall 142. Similar to the configuration described with reference to FIG. 4B, the bottom of the plasma lining structure 150 includes a plurality of liner slots that are aligned with corresponding slots defined in the bottom 143 of the C-shroud 140. Further, each section of the plasma lining structure 150 may include two or more segments. For example, the first segment 150b' may cover the upper surface of the bottom 143 of the C-shroud 140, and the second segment 154' may cover the inner surface of the side wall 142. A coupling mechanism is used to securely fix the two or more sections to each other and to the corresponding surfaces of the C-shroud 140. Each of the various configurations shown in FIGS. 4A - 4D defines a plasma lining structure 150 that covers at least the inner surface of the side wall 142 of the C-shroud 140, and some configurations cover additional inner surfaces of the C-shroud 140. The various configurations described herein block at least the horizontal view of the plasma to the side wall 142 of the C-shroud 140, which provides a direct path to ground.

[0054] The various configurations shown in FIGS. 4A - 4D define a plasma lining structure 150 where two or more sections are arranged to form a complete circle that covers at least the entire inner surface of the side wall 142 of the C-shroud 140. Alternatively, two or more sections may be arranged along the circular wall of the C-shroud 140 with a gap between a pair of adjacent sections. Additionally, these configurations may be extended to embodiments where one or more windows are defined in the vertical portion of the plasma lining structure 150 that covers the side wall 142 of the C-shroud 140.

[0055] FIG. 5A shows a vertical cross-sectional view of a plasma lining structure 150 having a plurality of sections attached to cover the entire inner surface of a plasma confinement structure 140 in one embodiment. The plasma confinement structure 140 is shown as a C-shroud 140. The plasma lining structure 150 covering the inner surface of the C-shroud 140 is shown to comprise three segments. For example, the first segment 150a covers the back surface of the upper portion 141 of the C-shroud 140 and the inner surface of the side wall 142. The second segment 150b1 is defined to cover a part of the upper surface of the bottom portion 143 of the C-shroud 140. The upper surface portion covered by the second segment 150b1 extends from the side wall 142 to the start of the section with the slot 145. The third segment 150b2 is defined to cover the remaining part of the upper surface of the bottom portion 143 and the downward extension connecting the C-shroud 140 to the ground ring 133. In the embodiment shown in FIG. 5A, the second segment 150b1 may have a recess in a portion adjacent to the side wall 142 of the C-shroud 140 where the first segment 150a is received. The third segment 150b2 comprises a plurality of liner slots (dashed lines in the figure) 504 that are aligned with the corresponding slots 145 (dashed lines in the figure) of the bottom portion 143 of the C-shroud 140. The fixing pins 506 are used to align the third segment 150b2 with the bottom portion 143 of the C-shroud 140 so as to place the liner slots 504 defined in the third section 150b2 and the slots 145 of the bottom portion 143 of the C-shroud 140 at the center. In some embodiments, a total of three fixing pins may be used to align the various sections of the plasma lining structure 150 with the C-shroud 140. In embodiments where the side wall 142 is defined as a separate part from the bottom portion 143 of the C-shroud 140, there may be a fixture for fixing the side wall 142 to the bottom portion 143. The downward extension of the C-shroud 140 may have a certain surface shape, and the downward extension of the third segment 150b2 of the plasma lining structure 150 is designed to conform to or supplement the surface shape of the downward extension of the C-shroud 140.

[0056] In an embodiment where the plasma lining structure 150 covers the entire inner surface of the C shroud 140 (e.g., the embodiments shown in FIGS. 4B and 5A), the C shroud 140 may be made of aluminum, and the plasma lining structure may be made of quartz. Quartz is a non-metallic heat insulator. In an embodiment where the plasma lining structure 150 covers only a part of the inner surface of the C shroud (e.g., the embodiments shown in FIGS. 4A, 4C, and 4D), the C shroud may be made of silicon, and the plasma lining structure 150 may be made of quartz. Alternatively, the plasma lining structure may be made of any other dielectric material (i.e., a non-metallic heat insulator). The thickness of the C shroud 140 is defined such that the plasma is sufficiently suppressed but ventilation for by-products and process gases to escape is not blocked. Similarly, the thickness of the plasma lining structure 150 may be defined such that the plasma lining structure 150 can sufficiently block the horizontal view of the RF plasma generated in the chamber 106. In one embodiment, the thickness of the plasma lining structure 150 may be from about 1 / 4 inch (0.635 centimeters) to about 3 / 4 inch (1.905 centimeters). When the plasma lining structure 150 lines the entire inner surface of the C shroud 140, or only the bottom 143 and the side walls 142, or only the top 141 and the side walls 142, the thickness of the plasma lining structure 150 may be uniform along different portions. In other embodiments, the thickness of the plasma lining structure 150 may be a first thickness along the side wall 142 of the C shroud 140 and a second thickness along the surface covering the back surface of the top 141 or the upper surface of the bottom 143. In such an embodiment, the first thickness is greater than the second thickness and is defined to sufficiently block the path of the RF plasma to the grounded side wall surface 142 of the C shroud 140.

[0057] The thickness of the plasma lining structure 150 is defined such that the plasma lining structure 150 is ensured to maintain a desired tolerance. In an embodiment where the plasma lining structure 150 covers only the inner surface of the side wall 142 of the C shroud 140, there may be a gap between the upper surface of the plasma lining structure 150 and the back surface of the upper portion 141 of the C shroud 140. This gap is defined to be small enough to allow the installation and attachment of different sections of the plasma lining structure 150 within the chamber 106. In some embodiments, this gap may be sized from about 1 / 12 inch (2.1082 centimeters) to about 1 / 20 inch (0.127 centimeters) in one embodiment. The height of the plasma lining structure 150 is defined by the height of the C shroud 140 used in the chamber 106 and may vary depending on the type of etching process performed in the chamber 106.

[0058] Figure 5B shows a cross-sectional view of another embodiment of the plasma confinement structure. In this embodiment, the plasma confinement structure is in the form of an "E shroud" 140'. The E shroud 140' includes an upper portion 141', a bottom portion 143', and side walls 142' extending between a first end of the upper portion (141') and the bottom portion (143'). The second end of the upper portion 141' is coupled to the back surface of the upper electrode, and the second end of the bottom is coupled to the mounting ring. The upper and bottom portions of the E shroud 140' are the same as the upper portion (141) and the bottom portion (143) of the C shroud 140. However, the side walls 142' are different from the side walls 142 of the C shroud 140. The side walls 142' of the E shroud 140' include a plurality of annular protrusions 144 extending horizontally inwardly from the inner surface of the side walls 142' towards the center of the chamber 106. The annular protrusions 144 are evenly arranged along the length of the side walls 142' of the E shroud 140'. The length of the inwardly extending annular protrusions 144 is defined to provide an unobstructed path for the plasma to escape through the liner slots defined in the bottom portion 143' of the E shroud 140'. The thickness of each annular protrusion 144 may match the side walls 142' of the E shroud 140', and / or the upper portion (141') and the bottom portion (143') in one embodiment. In another embodiment, the thickness of each of the annular protrusions 144 may be smaller or larger than the thickness of the upper portion (141') and the bottom portion (143') of the E shroud 140'. The bottom portion 143' of the E shroud 140' includes a plurality of slots 145' to allow the plasma to escape from the plasma region. The length of the annular protrusions 144 may be defined to provide an unobstructed path for the plasma to escape through the slots 145' defined along the bottom portion 143' of the E shroud 140'.

[0059] The annular protrusions 144 of the E shroud 140' are defined such that a first space is defined between the annular protrusion adjacent to the upper portion 141' (i.e., the annular protrusion immediately below the upper portion 141'). A second space is defined between the annular protrusion adjacent to the bottom portion 143' of the E shroud 140' (i.e., the annular protrusion immediately above the bottom portion 143'). A corresponding third space is defined between any pair of adjacent annular protrusions.

[0060] The plasma lining structure 150' is disposed in each of a first space defined between the annular protrusion and the top, a second space defined between the annular protrusion and the bottom, and a third space defined between any pair of annular protrusions 144 so as to sufficiently block access to the side wall 142' of the E shroud 140'. In an embodiment where the plasma lining structure 150' is disposed in the second space defined between the bottom and the adjacent annular protrusion, the size of the plasma lining structure 150' may be defined to provide a path for the plasma to escape through the slot 145'. In another embodiment, the upper surface of the bottom 143' is not provided with the plasma lining structure 150' so as to provide an unobstructed path for the RF plasma and by-products to escape from the plasma region. In yet another embodiment, the plasma lining structure 150' defined on the upper surface of the bottom 143' may include a liner slot that is aligned with the corresponding slot defined in the bottom 143'. The height of the plasma lining structure 150' is defined to be equal to the height of a part of the side wall between adjacent annular protrusions 144. When the plasma lining structure 150' is received on the uppermost annular protrusion or the bottom 143', the height of the plasma lining structure 150' is defined to be equal to the height of the side wall between the annular protrusion 144 of the E shroud 140' and the top (141') or the bottom (143'). The plasma lining structure 150' has an annular shape, is composed of two or more sections, and may be configured to line the entire side wall surface defined between each annular protrusion to form a complete circle, or may be designed to have a gap between each pair of adjacent sections. When the plasma lining structure 150' is designed to form a complete circle, each section may be connected to the adjacent section to define a connection interface. The connection may be made by a coupling mechanism such as a fixing pin, an alignment pin, a mating surface, etc. defined on the back surface or any other surface of each section. Each section may further be coupled to the corresponding surface of the E shroud by a fixing pin, an alignment pin, a mating surface, etc.In one embodiment, the mating surface may be defined to include, for example, one or more recesses defined in the upper surface of the annular protrusion of the E shroud or the upper surface of the bottom, and supplementary extensions defined on the surface of each section of the plasma lining structure 150'. The recesses and extensions are sized such that each extension fits snugly into the corresponding recess. These recesses, extensions, or coupling mechanisms are used to couple different sections of the plasma lining structure 150' to each other and to different surfaces of the E shroud 140' so as to provide a secure orientation for repeated mounting.

[0061] FIG. 6 shows a simplified cross-sectional view of a plasma lining structure 150 that lines the inner surface of the side wall 142 of the C-shroud 140. In some embodiments, the width of the side wall 142 of the C-shroud 140 is defined from about 1 / 4 inch (i.e., 0.25 inch (0.635 cm)) to about 3 / 4 inch (i.e., 0.75 inch (1.905 cm)). The outer height of the exemplary side wall 142 of the C-shroud 140 is defined in one embodiment from about 2 inches (5.08 cm) to about 2.5 inches (6.35 cm). The dimensions of the C-shroud 140 are provided as merely examples and should not be considered limiting. It should be understood that different processing chambers may use C-shrouds 140 of different dimensions based on the type of process being performed in each processing chamber. In one embodiment, the width of the plasma lining structure 150 is defined to be from about 1 / 8 inch (0.3175 cm) to about 3 / 4 inch (i.e., 0.75 inch (1.905 cm)). A gap is defined between the upper surface of the plasma lining structure 150 that lines the inner surface of the side wall 142 of the C-shroud 140 and the back surface of the upper portion 141 of the C-shroud 140. This gap is provided so that the plasma lining structure 150 can move to a fixed position within the C-shroud 140. In one embodiment, this gap is defined to be from about 1 / 32 inch (i.e., about 0.031 inch (0.07874 cm)) to about 1 / 4 inch (i.e., about 0.25 inch (0.635 cm)). The above dimensions of the various components of the C-shroud 140 (i.e., the plasma confinement structure) and the plasma lining structure 150 are provided as examples and should not be considered limiting. The height and width of the C-shroud 140 may vary depending on the type of process being performed and the type of processing chamber in which the C-shroud 140 is defined. As a result, the height and width of the plasma lining structure 150, and the gap between the upper surface of the plasma lining structure 150 and the bottom surface of the upper portion 141 of the C-shroud 140, may vary depending on the measurements of the C-shroud 140. Dimensions have been provided with respect to the C-shroud 140, but similar dimensions may be provided for the E-shroud 140'.

[0062] The various embodiments described herein provide control of the local tilt of 3D devices defined on a wafer by addressing density differences in different regions of the wafer. The density differences are addressed by providing a quartz liner to block the line of sight to the plasma ground plane (i.e., the sidewall of the C-shroud 140). Blocking the line of sight to the ground plane leads to a significant suppression of the plasma density along the edge region and the extreme edge region of the wafer. Thereby, the local tilt of the 3D devices in the edge region and the extreme edge region of the wafer is controlled. The amount of suppression of the plasma density in different regions of the wafer may be adjusted by adding windows or defining gaps in the plasma lining structure 150. The windows or gaps provide access to a very small portion of the grounded sidewall of the C-shroud 140. Access to a very small portion of the grounded sidewall allows some plasma to find a direct path to ground, which will adjust the plasma density in the regions adjacent to the window / gap (i.e., the edge region and the extreme edge region of the wafer), while the path to ground for most of the plasma is blocked by the plasma lining structure 150 that covers most of the sidewall of the C-shroud 140. The number and size of the windows or the size of the gaps may be defined based on the amount of adjustment to the plasma density required in different regions including the edge region of the wafer.

[0063] The number of windows provided may be even so as to be symmetric with respect to the plasma lining structure 150. It should be understood that the number of windows is limited such that most of the inner surface of the sidewall of the C-shroud 140 is reliably covered by the plasma lining structure 150 in order to sufficiently block the return path of the RF plasma to ground. Depending on the type of etching performed in the processing chamber and the amount of plasma suppression required in the edge region or other regions of the wafer, a plasma lining structure 150 having a suitable number of windows for lining at least the inner surface of the sidewall of the C-shroud 140 may be selected. The reduction of RF coupling by selecting a suitable plasma lining structure 150 results in a significant improvement in the inclined shape of the 3D device at the wafer edge. The inclined shape of the 3D device at the edge is consistent with the inclined shape of the 3D device at the center of the wafer. With an increase in the aspect ratio of the device defined on the wafer surface, the improvement in the inclined shape of the 3D device in the edge region results in excellent yield.

[0064] FIG. 7 is a simplified schematic diagram of a computer system 700 that may be coupled to a processing chamber to control the process recipes and functions of different components of the present disclosure. It should be recognized that the methods described herein may be implemented by a digital processing system such as a conventional general-purpose computer system. On the other hand, a dedicated computer designed or programmed to perform only one function may be used. The computer system includes a central processing unit (CPU) 704 coupled via a bus 710 to a random access memory (RAM) 706, a read-only memory (ROM) 712, and a mass storage device 714. The system controller program 708 resides in the RAM 706 but may also reside in the mass storage device 714.

[0065] The mass storage device 714 represents a persistent data storage device such as a floppy disk drive or a fixed disk drive, which can be local or remote. The network interface 730 provides a connection via the network 732 and enables communication with other devices. It should be recognized that the CPU 704 may be embodied in a general-purpose processor, a dedicated processor, or a specially programmed logic device. The input / output (I / O) interface provides communication with different peripheral devices and is connected to the CPU 704, the RAM 706, the ROM 712, and the mass storage device 714 via the bus 710. Examples of peripheral devices include a display device 718, a keyboard 722, a cursor control device 724, a removable media device 734, and the like.

[0066] The display device 718 is configured to display the user interface described herein. The keyboard 722, the cursor control device (e.g., a mouse) 724, the removable media device 734, and other peripheral devices are coupled to the I / O interface 720 to communicate information to the CPU 704 in the selection of commands. It should be recognized that data between external devices may be communicated through the I / O interface 720. Embodiments can also be implemented in a distributed computing environment where tasks are performed by a remote processing device connected through a wired or wireless network.

[0067] Embodiments may be implemented by various computer system configurations, including a handheld device, a microprocessor system, a microprocessor-based or programmable household appliance, a small computer, a mainframe computer, and the like. Embodiments can also be implemented in a distributed computing environment where tasks are performed by a remote processing device connected through a network.

[0068] With the above embodiments in mind, it should be understood that the embodiments can employ various computer-implemented operations including data stored in a computer system. These operations are operations that require physical manipulation of physical quantities. Every operation described herein that forms part of the embodiments is a useful machine operation. The embodiments also relate to a device or apparatus for performing these operations. The apparatus may be specially constructed for the required purposes, such as a dedicated computer. When defined as a special-purpose computer, the computer can operate for special purposes while also being able to execute other processes, program executions, or routines that are not part of the special purpose. Alternatively, the operations may be processed by a general-purpose computer selectively activated or configured by one or more computer programs stored in a computer memory, cache, or obtained via a network. When data is obtained over a network, the data may be processed by other computers on the network (e.g., a cloud of computing resources).

[0069] One or more embodiments can also be created as computer-readable code on a computer-readable medium. A computer-readable medium is any data storage device that can then store data readable by a computer system. Examples of computer-readable media include hard drives, network-attached storage (NAS), read-only memory, random access memory, CD-ROM, CD-R, CD-RW, magnetic tape, as well as other optical and non-optical data storage devices. The computer-readable medium can include computer-readable tangible media distributed on a network-coupled computer system so that the computer-readable code is stored and executed in a distributed fashion.

[0070] Although the method operations have been described in a particular order, other housekeeping operations may be performed between operations, or the operations may be adjusted so that they can occur at slightly different times, or it should be understood that the processing of the overlay operations may be distributed to a system that allows the processing operations to occur at various intervals as long as the processing is performed in a desired manner.

[0071] The above embodiments have been described in some detail for purposes of clarity of understanding, but it will be apparent that certain changes and modifications may be made within the scope of the appended claims. Accordingly, the embodiments should be regarded as illustrative rather than limiting, and the disclosed embodiments should not be limited to the details described herein, but may be modified within the scope of the appended claims and their equivalents. [Application Example 1] A plasma lining structure for use with a plasma confinement structure having an annular vertical sidewall with an inner surface, a plurality of sections configured to conform to and cover at least one or more portions of the inner surface of the sidewall, the plurality of sections being configured to be positioned between the plasma region of the processing chamber and the sidewall such that when the plasma lining structure and the plasma confinement structure are disposed in the plasma chamber, the plurality of sections face the plasma region. A plasma lining structure comprising a plurality of sections. [Application Example 2] The plasma lining structure according to Application Example 1, wherein each section of the plurality of sections is arcuate. A plasma lining structure. [Application Example 3] The plasma lining structure according to Application Example 1, wherein the plurality of sections are configured to form a ring that substantially covers the entire inner surface of the sidewall, and each pair of adjacent sections are joined to each other at a connecting interface. A plasma lining structure. [Application Example 4] The plasma lining structure according to Application Example 1, wherein a pair of adjacent sections are configured to define a gap therebetween, the gap exposing a corresponding portion of the inner surface of the sidewall to the plasma region. A plasma lining structure. [Application Example 5] The plasma lining structure according to Application Example 1, wherein each section includes one or more windows configured to expose a corresponding portion of the inner surface of the sidewall to the plasma region, and the corresponding portion exposed by the one or more windows provides a direct path for plasma to ground through the sidewall. A plasma lining structure. [Application Example 6] The plasma lining structure according to Application Example 1, wherein the plasma confinement structure is a C-shroud having an upper portion, a vertical portion representing the sidewall, and a bottom portion, and each of the plurality of sections includes a plurality of segments including a vertical segment configured to cover the vertical portion, an upper segment configured to cover the back surface of the upper portion, and a bottom segment configured to cover the upper surface of the bottom portion. A plasma lining structure. [Application Example 7] The plasma lining structure described in Application Example 6, wherein the bottom segment of each section includes a plurality of liner slots that are aligned with corresponding slots defined in the bottom of the C shroud, and is configured to provide an unobstructed path for plasma to escape from the plasma region, the plasma lining structure. [Application Example 8] The plasma lining structure described in Application Example 1, wherein the plasma confinement structure is made of at least one of aluminum and silicon, and the plasma lining structure is made of at least one of a dielectric material and quartz, the plasma lining structure. [Application Example 9] The plasma lining structure described in Application Example 1, wherein the plasma confinement structure is a C shroud having an upper portion, a vertical portion representing the side wall, and a bottom, each of the plurality of sections includes a plurality of segments including a vertical segment configured to cover the vertical portion and an upper segment configured to cover the back surface of the upper portion, the plasma lining structure. [Application Example 10] The plasma lining structure described in Application Example 1, wherein the plasma confinement structure is a C shroud having an upper portion, a vertical portion representing the side wall, and a bottom, each of the plurality of sections includes a plurality of segments including a vertical segment configured to cover the vertical portion and a bottom segment configured to cover the upper surface of the bottom, and the bottom segment includes a plurality of liner slots that are aligned with corresponding slots defined in the bottom, the plasma lining structure. [Application Example 11] The plasma lining structure described in Application Example 1, wherein the plurality of sections are configured to block a direct path to ground for plasma generated in the processing chamber through the side wall of the plasma confinement structure, the plasma lining structure. [Application Example 12] The plasma lining structure described in Application Example 1, wherein the plasma confinement structure is an E shroud having an upper portion, a vertical portion representing the side wall, a bottom, and one or more annular protrusions extending from the vertical portion The upper part and the adjacent first annular protrusion are configured to define a first space located therebetween, the bottom part and the adjacent second annular protrusion are configured to define a second space located therebetween, and a pair of adjacent annular protrusions are configured to define a corresponding third space located therebetween. A first group consisting of one or more of the plurality of sections is disposed in the first space, thereby covering a corresponding portion of the inner surface of the side wall. A second group consisting of one or more of the plurality of sections is disposed in the second space, thereby covering a corresponding portion of the inner surface of the side wall. A third group consisting of one or more of the plurality of sections is disposed in the corresponding third space, thereby covering a corresponding portion of the inner surface of the side wall, the plasma lining structure. [Application Example 13] The plasma lining structure according to Application Example 12, wherein at least one of the first group, the second group, and the third group includes at least a pair of adjacent sections configured to define a gap located therebetween, and the gap exposes a corresponding portion of the inner surface of the side wall to the plasma region, the plasma lining structure. [Application Example 14] A plasma confinement structure for use in the processing chamber for confining plasma generated in the processing chamber in a plasma region defined between an upper electrode and a lower electrode, an annular vertical side wall having an inner surface, a plasma lining structure including a plurality of sections configured to conform to and cover at least one or more portions of the inner surface, the plurality of sections being configured to be located between the plasma region and the side wall such that the plurality of sections face the plasma region when the plasma confinement structure and the plasma lining structure are disposed in the processing chamber, the plasma lining structure; A plasma confinement structure comprising. [Application Example 15] The plasma confinement structure according to Application Example 14, wherein the plasma confinement structure is circular, the plurality of sections are configured to form a ring substantially covering the entire inner surface of the side wall, and each pair of adjacent sections are joined to each other at a connecting interface surface, the plasma confinement structure. [Applicable Example 16] A plasma confinement structure according to Applicable Example 14, wherein a pair of adjacent sections are configured to define a gap therebetween, and the gap exposes corresponding portions of the inner surface of the sidewall to the plasma region. [Applicable Example 17] A plasma confinement structure according to Applicable Example 14, wherein each section includes one or more windows configured to expose corresponding portions of the inner surface of the sidewall to the plasma region, and the corresponding portions exposed by the one or more windows provide a direct path to ground for the plasma through the sidewall. [Applicable Example 18] A processing chamber for confining plasma generated within a plasma region within the plasma region, an upper electrode disposed at an upper portion of the processing chamber and configured to supply a processing gas from a gas source to the processing chamber, the upper electrode being electrically grounded; a lower electrode disposed at a bottom portion of the processing chamber, oriented opposite to the upper electrode, and defining the plasma region located therebetween, the lower electrode including a support surface for supporting a wafer and being connected to a plurality of radio frequency (RF) power sources via a corresponding matching network; a plasma confinement structure disposed between the upper electrode and the lower electrode and configured to confine the plasma within the plasma region, the plasma confinement structure including an annular vertical sidewall having an inner surface; a plasma lining structure including a plurality of sections adapted to and configured to cover at least one or more portions of the inner surface, the plurality of sections being configured to be located between the plasma region and the sidewall such that the plurality of sections face the plasma region when the plasma confinement structure and the plasma lining structure are disposed within the processing chamber; A processing chamber comprising the above. [Applicable Example 19] A processing chamber according to Applicable Example 18, wherein the plasma lining structure is made of at least one of a dielectric material and quartz, and the plurality of sections are configured to block a direct path to ground through the sidewall for the plasma generated within the processing chamber.

Claims

1. A plasma lining structure for use with a plasma confinement structure having an annular vertical sidewall with an inner surface, comprising a plurality of sections configured to conform to and cover at least one or more portions of the inner surface of the sidewall, the plurality of sections being located between the plasma region of the processing chamber and the sidewall such that when the plasma lining structure and the plasma confinement structure are disposed in the processing chamber, the plurality of sections face the plasma region, wherein a pair of adjacent sections are configured to define a gap therebetween, the gap exposing a corresponding portion of the inner surface of the sidewall to the plasma region, the plasma lining structure.

2. The plasma lining structure according to claim 1, wherein each section of the plurality of sections is arcuate, the plasma lining structure.

3. The plasma lining structure according to claim 1, wherein the plurality of sections are configured to form a ring substantially covering the entire inner surface of the sidewall, and each pair of adjacent sections are joined to each other at a connecting interface, the plasma lining structure.

4. The plasma lining structure according to claim 1, wherein each section further includes one or more windows configured to expose a corresponding portion of the inner surface of the sidewall to the plasma region, the corresponding portion exposed by the one or more windows providing a direct path for plasma to ground through the sidewall, the plasma lining structure.

5. The plasma lining structure according to claim 1, wherein the plasma confinement structure is a C-shroud having an upper portion, a vertical portion representing the sidewall, and a bottom portion, and each of the plurality of sections includes a plurality of segments including a vertical segment configured to cover the vertical portion, an upper segment configured to cover the back surface of the upper portion, and a bottom segment configured to cover the upper surface of the bottom portion, the plasma lining structure.

6. The plasma lining structure according to claim 5, The bottom segments of each of the sections include a plurality of liner slots that are aligned with corresponding slots defined in the bottom of the C shroud, and are configured to provide an unobstructed path for plasma to escape from the plasma region, a plasma lining structure.

7. The plasma lining structure according to claim 1, wherein the plasma confinement structure is made of at least one of aluminum and silicon, and the plasma lining structure is made of at least one of a dielectric material and quartz, a plasma lining structure.

8. The plasma lining structure according to claim 1, wherein the plasma confinement structure is a C shroud having an upper portion, a vertical portion representing the side wall, and a bottom, each of the plurality of sections includes a plurality of segments including a vertical segment configured to cover the vertical portion and an upper segment configured to cover the back surface of the upper portion, a plasma lining structure.

9. The plasma lining structure according to claim 1, wherein the plasma confinement structure is a C shroud having an upper portion, a vertical portion representing the side wall, and a bottom, each of the plurality of sections includes a plurality of segments including a vertical segment configured to cover the vertical portion and a bottom segment configured to cover the upper surface of the bottom, and the bottom segment includes a plurality of liner slots that are aligned with corresponding slots defined in the bottom, a plasma lining structure.

10. The plasma lining structure according to claim 1, wherein the plurality of sections are configured to block a direct path to ground for plasma generated in the processing chamber through the side wall of the plasma confinement structure, a plasma lining structure.

11. The plasma lining structure according to claim 1, wherein the plasma confinement structure is an E shroud having an upper portion, a vertical portion representing the side wall, a bottom, and one or more annular protrusions extending from the vertical portion The upper part and the adjacent first annular protrusion are configured to define a first space located therebetween, the bottom part and the adjacent second annular protrusion are configured to define a second space located therebetween, and a pair of adjacent annular protrusions are configured to define a corresponding third space located therebetween. A first group consisting of one or more of the plurality of sections is disposed in the first space, thereby covering a corresponding portion of the inner surface of the side wall. A second group consisting of one or more of the plurality of sections is disposed in the second space, thereby covering a corresponding portion of the inner surface of the side wall. A third group consisting of one or more of the plurality of sections is disposed in the corresponding third space, thereby covering a corresponding portion of the inner surface of the side wall, a plasma lining structure.

12. The plasma lining structure according to claim 11, wherein at least one of the first group, the second group, and the third group includes at least a pair of adjacent sections configured to define a gap located therebetween, and the gap exposes a corresponding portion of the inner surface of the side wall to the plasma region, a plasma lining structure.

13. A plasma confinement structure for use in the processing chamber for confining plasma generated in the processing chamber in a plasma region defined between an upper electrode and a lower electrode, an annular vertical side wall having an inner surface, a plasma lining structure including a plurality of sections configured to fit and cover at least one or more portions of the inner surface, and the plurality of sections are configured to be located between the plasma region and the side wall such that the plurality of sections face the plasma region when the plasma confinement structure and the plasma lining structure are disposed in the processing chamber, a plasma lining structure, comprising a pair of adjacent sections are configured to define a gap located therebetween, and the gap exposes a corresponding portion of the inner surface of the side wall to the plasma region, a plasma confinement structure.

14. The plasma confinement structure according to claim 13, The plasma confinement structure is circular, and the plurality of sections are configured to form a ring that substantially covers the entire inner surface of the sidewall, and each pair of adjacent sections are joined to each other at a connecting interface, the plasma confinement structure.

15. The plasma confinement structure according to claim 13, wherein each section further includes one or more windows configured to expose a corresponding portion of the inner surface of the sidewall to the plasma region, and the corresponding portion exposed by the one or more windows provides a direct path to ground for the plasma through the sidewall, the plasma confinement structure.

16. A processing chamber for use in confining plasma generated within a plasma region within the plasma region, an upper electrode disposed at an upper portion of the processing chamber and configured to supply a processing gas from a gas source to the processing chamber, the upper electrode being electrically grounded; a lower electrode disposed at a bottom of the processing chamber, oriented opposite to the upper electrode, and defining the plasma region located therebetween, the lower electrode including a support surface for supporting a wafer and being connected to a plurality of high-frequency (RF) power sources via a corresponding matching network, the lower electrode; a plasma confinement structure disposed between the upper electrode and the lower electrode and configured to confine the plasma within the plasma region, the plasma confinement structure including an annular vertical sidewall having an inner surface; a plasma lining structure including a plurality of sections adapted to and configured to cover at least one or more portions of the inner surface, the plurality of sections being configured to be located between the plasma region and the sidewall such that the plurality of sections face the plasma region when the plasma confinement structure and the plasma lining structure are disposed within the processing chamber, the plasma lining structure; comprising a pair of adjacent sections are configured to define a gap therebetween, the gap exposing a corresponding portion of the inner surface of the sidewall to the plasma region, the processing chamber.

17. The processing chamber according to claim 16, The plasma lining structure is made of at least one of a dielectric material and quartz, and the plurality of sections are configured to block a direct path to ground through the side wall for the plasma generated in the processing chamber, the processing chamber.

18. A plasma lining structure for use with a plasma confinement structure having an annular vertical side wall with an inner surface, a plurality of sections configured to conform to and cover at least one or more portions of the inner surface of the vertical side wall, the plurality of sections being configured to be located between the plasma region of the processing chamber and the vertical side wall such that the plurality of sections face the plasma region when the plasma lining structure and the plasma confinement structure are disposed in the processing chamber, the plasma lining structure comprising a plurality of sections, each section includes one or more windows configured to expose a corresponding portion of the inner surface of the vertical side wall to the plasma region, and the corresponding portion exposed by the one or more windows provides a direct path for the plasma to ground through the vertical side wall, the plasma lining structure.

19. A plasma confinement structure for use in a processing chamber for confining plasma generated in the processing chamber in a plasma region defined between an upper electrode and a lower electrode, an annular vertical side wall having an inner surface, and a plasma lining structure including a plurality of sections configured to conform to and cover at least one or more portions of the inner surface, the plurality of sections being configured to be located between the plasma region and the vertical side wall such that the plurality of sections face the plasma region when the plasma confinement structure and the plasma lining structure are disposed in the processing chamber, the plasma confinement structure comprising a plasma lining structure, each section includes one or more windows configured to expose a corresponding portion of the inner surface of the vertical side wall to the plasma region, and the corresponding portion exposed by the one or more windows provides a direct path for the plasma to ground through the vertical side wall, the plasma confinement structure.

20. A processing chamber for use in confining plasma generated within a plasma region within the plasma region, An upper electrode disposed above the processing chamber and configured to supply a processing gas from a gas source to the processing chamber, the upper electrode being electrically grounded; A lower electrode disposed at the bottom of the processing chamber, oriented opposite to the upper electrode, and defining the plasma region located therebetween, the lower electrode including a support surface for supporting a wafer, the lower electrode being connected to a plurality of high-frequency (RF) power sources via a corresponding matching network; A plasma confinement structure disposed between the upper electrode and the lower electrode and configured to confine the plasma to the plasma region, the plasma confinement structure including an annular vertical sidewall having an inner surface; A plasma lining structure including a plurality of sections configured to conform to and cover at least one or more portions of the inner surface, the plurality of sections being configured to be located between the plasma region and the vertical sidewall such that the plurality of sections face the plasma region when the plasma confinement structure and the plasma lining structure are disposed in the processing chamber; Each section includes one or more windows configured to expose a corresponding portion of the inner surface of the vertical sidewall to the plasma region, and the corresponding portion exposed by the one or more windows provides a direct path for the plasma to ground through the vertical sidewall. A processing chamber.

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