Converter-coupled plasma source design for dielectric thin film deposition

Abstract

1. An apparatus comprising: a process chamber, the process chamber comprising: a window, the window comprising a dielectric material that is transparent to radio frequency (RF) energy, the window having a first side and a second side opposite the first side; a collar assembly having an opening covered by the window and supporting the first side of the window; and one or more RF coils positioned above the second side of the window, wherein when viewed along a first axis perpendicular to the window, a radial distance between an outermost portion of the one or more RF coils and an innermost portion of the conductive portion of the collar assembly that intersects a first reference plane that is perpendicular to the first axis, and between the first side of the window and the one or more RF coils is 40 mm or greater.

Description

Incorporation by Reference

[0001] As part of the present application, a PCT request is filed concurrently with the present specification. Each application to which the present application claims the benefit and priority identified in the concurrently filed PCT request is hereby incorporated by reference in its entirety into the present specification for all purposes. Background

[0002] Plasma sources are used to generate plasma that produces neutral particles, ions, and / or radicals of a process gas as the process gas flows into the plasma sources. These particles may then be caused to flow to physically and / or chemically react with a material of interest. An electric field may be used to generate the plasma, and the electric field is generated from one or more coils.

[0003] The description of the background and context contained in the present specification is provided solely for the purpose of generally presenting the context of the present disclosure. A large part of the present disclosure presents the inventors' studies, and the mere fact that such studies are described in the background section or presented as context elsewhere in the present specification does not mean that they are recognized as prior art. SUMMARY OF THE INVENTION

[0004] Systems and methods relating to the design and use of radio frequency (RF) generators are disclosed herein. In one embodiment of the embodiments herein, an apparatus is provided which includes a process chamber, the process chamber comprising a window comprising a dielectric material that is transparent to radio frequency (RF) energy and having a first side and a second side opposite to the first side; a collar assembly defining an opening covered by the window and supporting the first side of the window; and one or more RF coils positioned above the second side of the window, wherein the distance between the outermost part of the one or more RF coils and the innermost part of the conductive portion of the collar assembly, and between the first side of the window and the one or more RF coils, is 40 mm or more, and intersects a first reference plane perpendicular to the first axis when viewed along the first axis perpendicular to the window.

[0005] In some embodiments, the dielectric material has a dielectric constant of less than 10. In some embodiments, the dielectric material is aluminum nitride, aluminum oxide, or both. In some embodiments, one or more coils have a total number of turns of 4 or less. In some embodiments, one or more coils have a total number of turns of 3 or less. In some embodiments, the diameter of the flat window is less than 350 mm. In some embodiments, the assembly further includes a housing mechanically coupled to the collar assembly, and one or more RF coils are located within the internal volume of the housing. In some embodiments, the collar assembly includes an annular structure that is not continuous in the circumferential direction. In some embodiments, the annular structure includes one or more gaps. In some embodiments, the assembly further includes one or more cooling structures that direct air toward the flat window. In some embodiments, the window has a thickness of 20 mm to 25 mm. In some embodiments, the opening has a diameter of 350 mm to 400 mm.

[0006] In some embodiments, the system further includes one or more processors and one or more memories connected to one or more processors, the one or more memories storing computer-executable instructions, which, when executed by one or more processors, control one or more processors to cause a first process gas, including hydrogen gas, to flow into a plasma volume below a window and to ignite a plasma using the first process gas, the plasma being generated by powering one or more RF coils. In some embodiments, the computer-executable instructions, when executed by one or more processors, control one or more processors to cause the first process gas to flow into the plasma volume and to cause the first process gas to flow into the plasma volume without the accompanying helium flow. In some embodiments, the plasma is an inductively coupled plasma. In some embodiments, one or more memories, when executed by one or more processors, store further computer-executable instructions that control one or more processors to transition the plasma to an inductively coupled plasma with the power of one or more RF coils less than 1000 W. In some embodiments, one or more memories store further computer-executable instructions, when executed by one or more processors, that control one or more processors to maintain a plasma volume pressure greater than 1 Torr in the process chamber. In some embodiments, one or more memories store further computer-executable instructions, when executed by one or more processors, that control one or more processors to maintain a plasma volume pressure of 1 Torr to 3 Torr in the process chamber. In some embodiments, the process chamber further includes a shower head located below the window. In some embodiments, the process chamber further includes a pedestal configured to support a substrate.

[0007] These and other features of the disclosed embodiments are described in detail below with reference to the associated drawings. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing a plasma generator according to various embodiments described herein.

[0009] [Figure 2] This figure illustrates the process flow of the method according to various embodiments described herein.

[0010] [Figure 3] This is a magnified view showing a portion of the plasma generator system depicted in Figure 1.

[0011] [Figure 4] Figure 1 is a top view of a portion of the plasma generator system.

[0012] [Figure 5] This diagram shows alternative coil designs according to various embodiments described herein. [Modes for carrying out the invention]

[0013] This disclosure relates to a process chamber having a radio frequency (RF) source for plasma processes. Plasma can be used in a variety of processes for physically and / or chemically modifying the surface of a workpiece. For example, plasma can be used to deposit or spray a layer of material onto a workpiece, to etch or sputter off undesirable material from a workpiece, or to carry out an ashing or stripping process on a workpiece. Plasma can be generated by a plasma generator system. The plasma generator system can cause a process gas to flow into a plasma volume subjected to an electric field. The electric field causes the process gas to dissociate into neutral particles, ions, and / or radicals, which can then be flowed onto the workpiece to chemically and / or physically modify it.

[0014] Figure 1 is a simplified cross-sectional view of a plasma generator system 100 according to an exemplary embodiment of the present invention. The plasma generator system 100 is configured to generate plasma that can be used to deposit or remove material from a workpiece 102. For example, the plasma generator system 100 may be used in conjunction with a system or component used in various plasma processing techniques such as plasma chemical vapor deposition, plasma etching, plasma stripping or ashing, sputtering, and plasma spraying. Thus, the workpiece 102 may be a substrate that can undergo one or more of the processes described above. For example, in one embodiment, the workpiece 102 may be made from relatively pure silicon, germanium, gallium nitride, or other semiconductor materials typically used in the semiconductor industry, or silicon mixed with one or more additional elements such as germanium and carbon. In another embodiment, the workpiece 102 may be a semiconductor substrate having layers deposited thereon during a conventional semiconductor fabrication process. In yet another embodiment, the workpiece 102 may be a component such as a sheet of glass, ceramic, or metal that can undergo plasma processing.

[0015] The plasma generator system 100 may be a remote device or a field module incorporated within a processing system such as a process chamber. According to an exemplary embodiment of the present invention, the plasma generator system 100 includes a housing 101, a window 104, a coil 108, an energy source 110, a controller 111, a gas flow distributor 106, and a shower head 112. In some embodiments, the plasma generator system 100 may be part of or connected to a process chamber 103 so that the shower head 112 distributes process gas toward a substrate 102. In the embodiment shown in Figure 1, the substrate 102 is located below the shower head 112 and is shown resting on a movable base 130. It will be understood that the shower head 112 may have any suitable shape and may have any suitable number and arrangement configuration of ports 186 for distributing process gas toward the substrate 102. Figure 1 shows the showerhead 112 as part of the plasma generator system 100, but in some embodiments, the showerhead 112 may be part of the process chamber 103 or may be omitted, i.e., the substrate 102 is exposed to the plasma without a showerhead between the substrate 102 and the plasma.

[0016] The window 104, together with the color assembly 116 and showerhead 112, can define a plasma volume 118 configured to receive a processing gas that can be ionized by an electric field and converted into a plasma, containing species such as electrons, ions, and reactive radicals, for depositing material onto the workpiece 102 or removing material from the workpiece 102. In some embodiments, the window 104 may have a first side 156 facing the plasma volume 118 and a second side 157 opposite the first side 156 and facing the coil 108. In this regard, the window 104 is made from a material that is permeable to an electric field. According to exemplary embodiments, the window 104 may include one or more materials having the aforementioned properties. For example, the window 104 may be made from an insulating material such as a dielectric material including, but not limited to, aluminum nitride, silicon dioxide, aluminum oxide, or other ceramics. In some embodiments, the window 104 may include a dielectric material having a dielectric constant of less than 10. In some embodiments, the window may be 20 mm thick, or 20 mm to 25 mm thick.

[0017] In any case, in order to contain the plasma within the plasma volume 118, the collar assembly 116 can act as a side wall and define an opening that partially defines the plasma volume 118. The collar assembly 116 can have any thickness suitable for containing the plasma within the plasma volume 118 and that does not interfere with the electric field generated by the coil 108. In an exemplary embodiment, the collar assembly 116 has a thickness in the range of 4 mm to 6 mm. In another exemplary embodiment, the collar assembly 116 has a substantially uniform thickness (e.g., ±0.5 mm) along its entire axial length. In yet another embodiment, the collar assembly 116 has a thickness that varies along its axial length. In some embodiments, the opening of the collar assembly may have a diameter of 370 mm. In some embodiments, the opening of the collar assembly may have a diameter of 350 mm to 400 mm.

[0018] In some embodiments, the collar assembly 116 may include an annular structure 121. The annular structure can secure the window 104 together with the O-ring 132 during the operation of the plasma generator system. In some embodiments, the annular structure may be a continuous ring having an inner diameter of 390 mm. In some embodiments, the annular structure may have an inner diameter of 380 mm to 400 mm. As will be further discussed below, in some embodiments, the annular structure may not be continuous in the circumferential direction and may include one or more gaps.

[0019] To provide an electric field within the plasma volume 118, one or more coils 108 are positioned above the window 104. In exemplary embodiments, the coils 108 are made of a conductive material, such as copper or a copper alloy, and each coil may have a first end and a second end. The first end can be electrically coupled to the energy source 110, while the second end can be electrically coupled to electrical ground. In some embodiments, one or more coils 108 may be 3 mm above the window 104, or 2 mm to 4 mm above the window 104. This may allow, for example, a cooling gas of air to flow below and around the coils 108.

[0020] In some embodiments, the coil 108 may be sized to fit within or inscribe within an annular region having a certain inner and outer diameter. In some embodiments, the inner diameter of the coil is 170 mm (i.e., the diameter of the circle enclosed by the coil 108). In some embodiments, the inner diameter of the coil is 160 mm to 180 mm. The inner diameter can be defined to provide space for the gas flow distributor 106 and the cooling structure 109. The gas flow distributor 106 extends through the window 104 and can flow process gas into the plasma volume, while the cooling structure 109 can flow cooling gas 127 downwards toward the window 104, which then flows across the window 104 and the coil 108 to cool the coil 108 and / or the window 104 during system operation.

[0021] Conversely, as will be discussed further below, the outer diameter of the coil 108 can be limited to reduce capacitive coupling between the coil 108 and the annular structure 121 or collar assembly 116. In some embodiments, the outer diameter of the coil is 300 mm (i.e., the diameter of the circle surrounding the coil 108). In some embodiments, the outer diameter of the coil is 290 mm to 310 mm.

[0022] In some embodiments, the housing 101 covers one or more coils and other components that may be located above the window 104. In some embodiments, the housing 101 may be mechanically coupled to the annular structure by various fasteners. In some embodiments, the housing may be part of the annular structure, for example, the housing may be welded to the annular structure, or both elements may be fabricated as a single unit. In some embodiments, the housing 101 is coupled to the collar assembly via the annular structure 121. The housing 101, together with the window 104, can define an internal volume, and one or more coils, as well as various other components such as valves and piping for process gases, may be located within the internal volume.

[0023] To control the operating mode of the energy source 110, a controller 111 is operatively coupled to the energy source. The controller 111 may be an analog controller, a discrete logic controller, a programmable array controller (PAL), a programmable logic controller (PLC), a microprocessor, a computer capable of executing the sequence of events outlined in method 700 described later, or any other device. In one exemplary embodiment, the controller 111 determines the magnitude of power supplied to one or more coils 108 and provides commands to the energy source 110. In addition to controlling the energy source 110, the controller 111 may also be operatively coupled to the process gas source 177, and may provide commands to the process gas source to supply a certain amount of process gas to the plasma volume 118. Although the controller 111, the gas source 177, and the energy source 110 are shown within the housing 101, it should be understood that these components may be located outside the housing and connected to components inside the housing (e.g., the coil 108 or the gas flow distributor 106).

[0024] The process gas source 177 may include one or more gas sources and corresponding one or more valves or other flow control components (e.g., mass flow controllers or liquid flow controllers). The controller 111 is connected to the one or more valves or other flow control components, and can cause them to switch states, thereby allowing different gases or gas combinations to flow at different times and / or flow rates. In some embodiments, the one or more gas sources may be fluidly connected to a mixing vessel for blending and / or conditioning the process gas prior to delivering the process gas to the gas flow distributor 106.

[0025] The energy source 110 may be a radio frequency (RF) energy source, or another energy source capable of supplying power to and activating the coil 108 to form an electric field. In an exemplary embodiment, the energy source 110 comprises an RF generator selected for its ability to operate at a desired frequency and supply a signal to the coil 108. For example, the RF generator may be selected to operate within a frequency range of 0.2 MHz to 20.0 MHz. In one exemplary embodiment, the RF generator may operate at 13.56 MHz. In an exemplary embodiment, the energy source 110 may comprise a matching network disposed between the RF generator and the coil 108. The matching network may be an impedance matching network configured to match the impedance of the RF generator to the impedance of the coil 108. In this regard, it will be appreciated that the matching network may be constructed from a combination of components such as a phase angle detector and a control motor, though other components may also be included in other embodiments.

[0026] The process gas may diffuse into the gas flow distributor 106 before being injected into the plasma volume 118. In this way, the gas can be distributed substantially uniformly into the plasma volume 118. In some embodiments, the window 104 may include an inlet 148 to the plasma volume 118 that allows gas to flow into the plasma volume 118. In some embodiments, the gas flow distributor 106 is disposed within the plasma volume inlet 148. According to one exemplary embodiment, the gas flow distributor 106 is non-conductive and is constructed from a material capable of withstanding corrosion when exposed to the process gas. Suitable materials include, for example, dielectric materials such as silicon dioxide.

[0027] Continuing with reference to Figure 1, when the energy source 110 activates the coil 108, an electric field is formed within a selected portion of the plasma volume 118, thereby ionizing the work gas that can flow through it to form an ionized gas. As used herein, the term “ionized gas” may include, but is not limited to, charged particles, ions, electrons, neutral species, excited species, reactive radicals, dissociated radicals, and any other species that may be generated when the work gas flows through the electric field. To control the dispersion of the ionized gas over the workpiece 102, a showerhead 112 can be positioned between the plasma volume and the workpiece. In one exemplary embodiment, the showerhead 112 may be made from any suitable material that is relatively inert to the plasma, such as aluminum nitride, alumina, or other ceramics. Generally, the showerhead is sized to distribute the gas over the entire workpiece 102 and therefore has a corresponding suitable diameter.

[0028] The shower head 112 may have through-holes that allow gas to pass through it. In particular, the shower head 112 includes through-holes 186 that are appropriately sized to distribute the ionized gas substantially uniformly across the workpiece 102 and are thus spaced apart. In one exemplary embodiment, the through-holes 186 have a diameter in the range of 2 mm to 10 mm. Additionally, in one exemplary embodiment, the through-holes 186 are arranged in a substantially uniform pattern on the shower head 112, while in another exemplary embodiment, the through-holes 186 are arranged in a non-uniform pattern, for example, with a distribution of holes concentrated in the center or a distribution of holes concentrated at the edges.

[0029] In an exemplary embodiment of the present invention, the shower head 112 may be directly coupled to the collar assembly 116, as shown in Figure 1. For example, the shower head 112 may be coupled to the collar assembly 116 via bolts, clamps, adhesives or other fastening mechanisms. In another embodiment, the shower head 112 may be integral with the collar assembly 116.

[0030] Figure 1 shows an embodiment of a plasma generator system 100 including certain components, but it should be understood that additional components or components with different shapes than those shown in Figure 1 may be used as substitutes.

[0031] Figure 2 shows a flowchart of a plasma forming method 200 according to an exemplary embodiment, which can be used with a system 100 and a controller such as a controller 111, and which can be adapted to cause the system 100 to perform one or more steps of method 700. For example, the controller may be adapted to provide commands to an energy source such as an energy source 110 to perform the various steps below, and / or the controller may be adapted to provide commands to a processing gas source such as a processing gas source 177 to perform one or more of the various steps below. In an exemplary embodiment, a first plasma is formed in a plasma volume (step 202).

[0032] In some embodiments, step 202 may include flowing a process gas into the plasma volume (step 204) before, after, or simultaneously with forming an electric field (step 206). The process gas can be injected into the plasma volume through inlet 148 and / or gas flow distributor 106. In some embodiments, the gas flow distributor may have multiple openings for distributing the process gas throughout the plasma volume.

[0033] The specific gas selected as the process gas may depend on the specific process in which the plasma may be used. In exemplary embodiments, the process gas includes fluorine-containing gases. Examples of fluorine-containing gases suitable for use include nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), hexafluoroethane (C2F6), tetrafluoromethane (CF4), trifluoromethane (CHF3), difluoromethane (CH2F2), octofluoropropane (C3F8), octofluorocyclobutane (C4F8), octofluoro[1-]butane (C4F8), octofluoro[2-]butane (C4F8), octofluoroisobutylene (C4F8), fluorine (F2), and others. In another embodiment, the process gas may include a hydrogen-containing gas such as H2. In another embodiment, the process gas may include an oxygen-containing gas. For example, the oxygen-containing gas may include, but is not limited to, oxygen (O2) and N2O. In other embodiments, the process gas may additionally include an inert gas, such as nitrogen (N2), helium, or argon. In other embodiments, different gases and different ratios may be used. In some embodiments, the process gas may flow without an inert gas, for example, without flowing helium gas.

[0034] In some embodiments, method 200 may be carried out under vacuum pressure. In some embodiments, the pressure may be 0.5 Torr to 10 Torr, or 1 Torr to 3 Torr.

[0035] According to another exemplary embodiment, step 202 may further include forming an electric field within the plasma volume to form a first plasma (step 206). During operation of the plasma generator system 100, an energy source 110 is connected to each coil and supplies power to the coils to form an electric field. According to an exemplary embodiment of the present invention, step 206 may include supplying a first magnitude of power to the coils of the system to form an electric field. In one embodiment, the first magnitude of power is a magnitude sufficient to cause the system to operate in an inductive mode, from which the system transitions from an initial capacitive mode. Thus, the first magnitude of power may be a value within a range having a lower limit, the lower limit being a magnitude of power suitable for causing the system to transition from capacitive mode to inductive mode.

[0036] During operation, two different electric field configurations are generated: a capacitively coupled electric field (capacitive component) and an inductively coupled electric field (inductive component). The capacitively coupled electric field is defined by electric field lines that extend between adjacent turns of the coil and have a component perpendicular to the surface of the window. The inductively coupled electric field is generated when a current in the coil produces an RF magnetic field that penetrates the window and induces an electric field as described by Faraday's law. The inductively coupled electric field typically has electric field lines that do not have a component perpendicular to the surface of the chamber.

[0037] When the system is powered on and power is first supplied to the coil, the relative strength of the capacitive electric field is greater than that of the inductive electric field. In such a case, the system is in "capacitive mode". As the power increases, the relative strength of the capacitively coupled electric field decreases, and therefore the strength of the inductively coupled electric field increases. This may be a result of increased power absorption by the plasma, which in turn increases the number of charged particles, leading to an increase in the magnitude of the current in the coil and a larger proportion of the power being coupled to the inductive component. At a certain power level, the system may experience a mode transition (known in the art as a "mode jump") in which a rapid increase in the inductive component occurs along with a rapid decrease in the associated capacitive component. In such a case, the system is in "inductive mode".

[0038] The specific power level required to transition from capacitive to inductive mode can depend on the system design. Specifically, the particular current, voltage, and power needed to generate capacitive and / or inductive modes depend heavily on the window, plasma volume, and coil configuration and dimensions, process chemistry, and process parameters.

[0039] According to an exemplary embodiment, the system may be configured similarly to that in Figure 1. In such a case, the system may be designed such that the first magnitude of power has a lower limit of 600 watts or 1000 watts, which can be used to transition the system from capacitive mode to inductive mode.

[0040] After the first plasma is formed, the first plasma can be used in various processes in which the plasma can be used to modify the surface of a workpiece (step 208). According to an exemplary embodiment, a continuous supply of a processing gas can be supplied into the plasma volume and, together with the first plasma, can be enabled to circulate through an electric field, and an RF current can be continuously supplied to a coil, resulting in an inductive mode that generates an RF electric field in the chamber. As the processing gas circulates, the charged particles constituting the plasma are accelerated within the plasma volume, and at least a portion of the processing gas is dissociated into reactive radicals, which can be flowed to the workpiece located below the showerhead of the plasma volume. For example, in an embodiment in which the processing gas contains a fluorine-containing gas, a portion of the fluorine-containing gas is ionized to form electrons, fluorine ions, and reactive fluorine radicals. In an exemplary embodiment of the present invention, some of the reactive fluorine radicals can flow from the plasma volume through the showerhead and be deposited on the workpiece, while other portions of the reactive fluorine radicals can be recirculated within the plasma volume before being deposited on the workpiece. After the workpiece has been processed, it can be moved to another part of the system.

[0041] As mentioned above, in various embodiments, the process gas used in the process shown in Figure 2 may include an inert gas such as helium. Helium can act to stabilize the plasma by being an electron-donating gas (i.e., a species with low ionization energy). In some embodiments, helium may not be part of the process gas. In such embodiments, the plasma may have enhanced etching properties, particularly in the case of a plasma formed from a process gas containing H2 or NF3. In such embodiments, window 104 may be subjected to additional corrosion from the plasma compared to a plasma from a process gas containing helium, resulting in a reduced lifespan for window 104. In some embodiments, window 104 includes a material that is permeable to RF energy while being resistant to corrosion by H2 or NF3 plasma, such as aluminum nitride.

[0042] Furthermore, in various embodiments, Method 200 may be implemented when the RF generator operates at a high power, for example, 3000 W or more. In some embodiments, high-power operation increases the temperature of the window facing the plasma volume, causing a more pronounced thermal gradient within the window 104 between the side facing the plasma and the opposite side cooled by the cooling structure 109. In some embodiments, the window 104 includes a material having high thermal conductivity to reduce the risk of thermal stress cracks within the window 104 resulting from thermal stress across the window 104, which arise from uneven heating of the window 104. For example, the window 104 may include a thermally conductive material having a temperature of less than 200°C while Method 2 is operating at an RF power of 3000 W. In some embodiments, the thermally conductive material may include aluminum nitride.

[0043] As mentioned above, the configuration and dimensions of the coils can affect the power required to cause the system to transition between capacitive and inductive modes. Figure 3 shows an enlarged view of a portion of Figure 1. During the operation of the plasma generator system 100, power is supplied to the coils to form an electric field, and the first magnitude of power required to cause a mode jump can be controlled, at least in part, by the coil configuration. In some embodiments, particularly in embodiments using a pure H2 process gas or a process gas without helium, the first magnitude of power increases to, for example, 1000W or more, which is undesirable because operation at higher power increases wear on various components, thus reducing the lifespan of the components, lowering the efficiency of the plasma generator system, and also incurring higher costs due to increased power consumption. The inventors have tested several coil designs to improve the efficiency of the plasma generator system, in particular to lower the power threshold required for a mode jump in such a system. Typically, increasing the number of coils increases the inductance generated by the coils, thereby reducing the lower limit of the first magnitude of power, i.e., the threshold power required to transition the system from capacitive mode to inductive mode. Furthermore, reducing the spacing between coils can also increase inductance and thus reduce the first magnitude of power. However, there is a lower limit to such spacing because arc discharge may occur between the coils, potentially short-circuiting them, or stray capacitance may hinder the inductance generated by the coils, increasing the power required to cause a mode jump.

[0044] However, when the inventors increased the number of coils to, for example, a total of 6 turns in a system such as the example shown in Figure 1, mode jumps required additional power. Furthermore, when the inventors increased the spacing between coils to reduce inter-coil coupling, the mode jump power threshold did not decrease, and sometimes even increased. Instead, the inventors determined that reducing the number of coils and / or the outer diameter of the coils reduced the transition power threshold.

[0045] Without being bound by theory, during operation, the coil may inductively couple with the annular structure and / or collar assembly, generating eddy currents that divert power that would otherwise be used for plasma generation. Additional power is required to compensate for eddy current losses and achieve the desired amount of power delivery to the plasma, increasing the RF power threshold for mode jumps. As mentioned above, the inner diameter of the coil 108 may be limited by components located near the center of the system 100, such as the gas flow distributor 106 or the cooling structure 109. Thus, the radial distance 122 between the coil 108 and the annular structure 113 or collar assembly 116 (which may typically include a conductive metal such as aluminum) can be reduced by increasing the number of coils or the spacing between coils (while keeping the coil width / thickness the same). The reduction in radial distance increases eddy current formation in one or both of those elements, increasing the RF power requirement to cause mode jumps. Furthermore, in some embodiments, eddy currents are less (or have a less significant impact) in the portion of the collar assembly 116 below the window 104. Therefore, while some parts of the color assembly 116 may be closer to the coil 108 than any part of the annular structure 121, increasing the distance between the annular structure 121 (or any element above the first side 156 of the window 104) and the coil 108 can significantly reduce the RF power threshold for transitioning the plasma from capacitive mode to inductive mode.

[0046] Therefore, in some embodiments, the radial distance 122 is between the coil 108 and the inner edge of the annular structure 121 (as shown by the dashed line). In some embodiments, the radial distance 122 is above the first side 156 of the window 104. That is, between the first side 156 of the window 104 and the coil 108 Between the outermost portion 144 of one or more coils 108 (as indicated by the dashed circle surrounding the coils 108) and the innermost portion 146 of the conductive part of the color assembly 116 (including the annular structure 121, indicated by the dashed line) intersects with the reference plane 113 located there. of This is the radial distance. Returning to Figure 3, the reference plane 113 coincides with the top surface of the annular structure 121 and the second side 157 of the window 104, although in other embodiments, the top surface of the annular structure 121 may be above or below the second side 157 of the window 104. In some embodiments, the reference plane 113 is above the first side of the window 104. In some embodiments, the reference plane 113 may be perpendicular to the first axis 114 which is perpendicular to the top surface of the window 104. In some embodiments, the radial distance 122 is measured along a line that intersects the first axis 114 and / or coincides with the reference plane 113.

[0047] In various embodiments, the radial distance 122 may be at least 40 mm, at least 50 mm, at least 60 mm, 40 mm to 60 mm, or 60 mm. Generally, the smaller the outer diameter of the coil 108, the larger the radial distance 122.

[0048] Figure 4 shows a top view of the plasma generator system 100. As mentioned above with respect to Figure 3, the radial distance 122 exists between the outermost part of the coil 108 and the annular structure 121. In some embodiments, the annular structure may be a discontinuous ring in order to reduce the formation of eddy currents within the annular structure. In some embodiments, one or more gaps 124 exist within the annular structure 121. Figure 4 shows one gap, but two or more gaps may exist. In some embodiments, multiple gaps may be evenly spaced around the annular structure 121. The gaps can reduce eddy current formation by obstructing the flow of current around the annular structure. In some embodiments, the gaps are located within the conductive portion of the annular structure. In some embodiments, the gaps may be air, while in other embodiments, the gaps may be electrical gaps filled with, for example, a plastic insulator or dielectric that obstructs the flow of current. In some embodiments, the housing 101 may have gaps similar to those in the annular structure, i.e., air gaps or electrical gaps.

[0049] As mentioned above, one or more coils 108 are located above the window 104 and can be activated to form an electric field. In the embodiment of Figure 4, there are a first coil 140a and a second coil 140b, but more or fewer coils may be present in various embodiments. Each coil may have first ends 136a and 136b and second ends 137a and 137b. The first ends 136a and 136b can be electrically coupled to the energy source 110. The second ends 137a and 137b can be electrically coupled to electrical ground and terminate the coil. It should be understood that connections of other configurations are within the scope of this disclosure.

[0050] Each coil forms a loop around a central axis (such as axis 114 shown in Figure 1). Each substantially complete loop formed by the coils around the central axis (with the ends of the loops separated by radial gaps) can be considered as one turn. Thus, in the example in Figure 4, each of coils 136a and 136b has two turns. In various embodiments, the total number of turns by one or more coils can include the sum of the turns of each coil (thus, in Figure 4, coil 108 can have a total of 4 turns). The coils shown in Figure 4 are substantially symmetric with respect to the central axis, but in other embodiments, they may be asymmetric. For example, in embodiments where multiple coils are implemented, the first coil may have more or fewer turns than the second coil, and the total number of turns may be odd (for example, the first coil having 1 turn and the second coil having 2 turns may have a total of 3 turns). In some embodiments, the coils may have a substantially helical shape, such as that shown in Figure 4.

[0051] In various embodiments, there is a coil spacing 129 between the wires of the coil. If the coil turns are too close together, arc discharge or stray capacitance may occur between the coils, which can short-circuit the coils or, in other ways, reduce the inductance generated by the coils. The smallest coil spacing can inhibit these effects, and such a coil spacing may depend on the frequency of the RF source connected to the coils. In some embodiments, the coil spacing is at least 6 mm.

[0052] In some embodiments, a portion of the coil may follow a non-helical path, for example, an arched portion interposed by a straight portion. Figure 5 shows a coil 508 having a straight portion 509. In such embodiments, there may be multiple straight portions, each representing a 180-degree rotation from another straight portion. In some embodiments, the coil may not have a helical shape. In some embodiments using multiple coils, one coil may be an "inner coil" having an outer diameter smaller than the inner diameter of the "outer coils," resulting in the inner coil being closer to the central axis than the outer coils. Furthermore, in some embodiments, each coil may not achieve a complete rotation or turn. For example, two coils may each achieve 1.5 rotations and each have 1.5 turns, resulting in a total of 3 turns. Other embodiments fall within the scope of this disclosure. As mentioned above, one or more coils may be present, for example, two coils or three coils.

[0053] As mentioned above, in some embodiments, the controller 111 is part of a system, which may be part of the examples described above. Such a system may include semiconductor processing equipment, including one or more processing tools, one or more processing chambers, one or more platforms for processing, and / or specific processing components (such as a wafer pedestal, gas flow system, etc.). These systems may be integrated with electronic equipment to control their operation before, during, and after processing of semiconductor wafers or substrates. The electronic equipment may be referred to as a “controller” that can control various components or sub-components of one or more systems. Depending on the processing requirements and / or type of the system, the controller 111 can be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and operation settings, and wafer transfer into and out of tools and / or load locks connected to or interfaced with the particular system.

[0054] In short, a controller can be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, and so on. An integrated circuit may include a chip in the form of firmware that stores program instructions, a chip defined as a digital signal processor (DSP), an application-specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files) that define operating parameters for performing a particular process on or for a semiconductor wafer, or for a system. In some embodiments, the operating parameters may be part of a recipe defined by a process engineer to perform one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0055] In some embodiments, the controller may be part of a computer that is integrated with, coupled to, or otherwise networked to the system, or a combination thereof. For example, the controller may be in all or part of a “cloud” or fab-host computer system that can enable remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of a fabrication operation, investigate the history of past fabrication operations, investigate trends or performance metrics from multiple fabrication operations, modify parameters of the current process, set processing steps to follow the current process, or start a new process. In some examples, a remote computer (e.g., a server) may provide a process recipe to the system via a network that may include a local network or the internet. The remote computer may then include a user interface that enables input or programming of parameters and / or settings communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data specifying the parameters of each processing step performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed and the type of tool to which the controller is interfaced or configured to control. Therefore, as described above, the controller can be distributed by including one or more discrete controllers that are networked together and function toward a common purpose such as the processes and control described herein. An example of a distributed controller for such purposes is one or more integrated circuits on the chamber that communicate with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that, in combination, control the processes on the chamber.

[0056] Without limitation, exemplary systems may include plasma etch chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, beveled edge etch chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etch (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing systems associated with or that may be used in the fabrication and / or manufacture of semiconductor wafers.

[0057] As mentioned above, depending on one or more process steps performed by the tool, the controller may communicate with other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, the main computer, another controller, or one or more of the tools used for material transport to tool locations and / or load ports within the semiconductor manufacturing plant, and from there to carry containers of wafers.

[0058] conclusion A system and method are provided herein that offer improved plasma generation capabilities superior to conventional systems. The plasma generator system described above experiences reduced downtime between plasma generation processes compared to conventional systems, while also reducing exposure of surrounding system components to high energy levels. As a result, the improved plasma generator system includes components such as RF components, gas flow distributors, and tubes, which have improved service life compared to the components of conventional plasma generator systems. Additionally, system maintenance costs are also reduced.

[0059] Various modifications to the embodiments described herein will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of this disclosure. Accordingly, the claims are not intended to be limited to the embodiments shown herein, but rather to conform to the broadest scope that is consistent with this disclosure, the principles disclosed herein, and the novel features.

[0060] Certain features described herein in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented separately or in any suitable partial combination in multiple embodiments. Furthermore, features may be described above as acting in a certain combination, and may even be initially claimed as such, but one or more features from the claimed combination may, in some cases, be removed from that combination, and the claimed combination may cover partial combinations or variations of partial combinations.

[0061] Similarly, while operations are depicted in a specific order in the drawings, this should not be understood as requiring that such operations be performed in a specific or sequential order as illustrated, or that all illustrated operations be performed to achieve a desired result. Furthermore, drawings may schematically depict another exemplary process in the form of a flowchart. However, other operations not depicted can be incorporated into the schematically shown exemplary process. For example, one or more additional operations can be performed before, after, simultaneously with, or in between any of the illustrated operations. In certain environmental conditions, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged in multiple software products. In addition, other embodiments are within the scope of the following claims. In some cases, the operations described in the claims may be performed in a different order and still achieve the desired result. [Application Example 1] A device, The process chamber comprises, A window comprising a dielectric material that is transparent to radio frequency (RF) energy, having a first side and a second side opposite to the first side, A collar assembly having an opening covered by the window and supporting the first side of the window, A device comprising: one or more RF coils positioned above the second side of the window, wherein, when viewed along a first axis perpendicular to the window, the radial distance between the outermost part of the one or more RF coils and the innermost part of the conductive portion of the color assembly, and between the first side of the window and the one or more RF coils, intersects a first reference plane perpendicular to the first axis, is 40 mm or more. [Example 2] The apparatus described in Example 1, wherein the one or more coils include a total number of turns of 4 or less. [Application Example 3] The apparatus described in Application Example 1, wherein the one or more coils include a total number of turns of 3 or less. [Application Example 4] The apparatus described in Application Example 1, wherein the diameter of the flat window is less than 350 mm. [Application Example 5] The apparatus according to Application Example 1, further comprising a housing mechanically coupled to the color assembly, wherein the one or more RF coils are located within the internal volume of the housing. [Example 6] The apparatus according to Example 1, wherein the color assembly includes an annular structure with one or more gaps. [Application Example 7] The apparatus described in Application Example 6, wherein one or more gaps contain air. [Application Example 8] The apparatus according to Application Example 6, wherein one or more gaps contain a dielectric material. [Application Example 9] The apparatus according to Application Example 1, further comprising one or more cooling structures that direct air toward the flat window. [Application Example 10] The apparatus described in Application Example 1, wherein the window has a thickness of 20 mm to 25 mm. [Application Example 11] The apparatus described in Application Example 1, wherein the opening has a diameter of 350 mm to 400 mm. [Application Example 12] An apparatus according to Application Example 1, wherein the dielectric material has a dielectric constant of less than 10. [Application Example 13] An apparatus according to Application Example 1, wherein the dielectric material is aluminum nitride, aluminum oxide, or both. [Application Example 14] The apparatus according to Application Example 1, wherein the process chamber further comprises a shower head located below the window. [Application Example 15] The apparatus according to Application Example 1, wherein the process chamber further comprises a base configured to support a substrate. [Application Example 16] An apparatus according to any one of Application Examples 1 to 15, further comprising one or more processors and one or more memories connected to the one or more processors, wherein the one or more memories store computer executable instructions, and when the computer executable instructions are executed by the one or more processors, A first process gas containing hydrogen gas is introduced into the plasma volume below the window. An apparatus that controls one or more processors to ignite a plasma using the first process gas, the plasma being generated by powering one or more RF coils. [Example 17] A computer-executable instruction for the apparatus described in Example 16, wherein, when executed by one or more processors, it controls one or more processors to cause the first process gas to flow into the plasma volume and to cause the first process gas to flow into the plasma volume without the accompanying helium flow. [Application Example 18] An apparatus as described in Application Example 16, wherein the plasma is inductively coupled plasma. [Example 19] The apparatus according to Example 18, wherein one or more memories store further computer-executable instructions that, when executed by the one or more processors, control the one or more processors to transition the plasma into an inductively coupled plasma at a power of one or more RF coils less than 1000 W. [Example 20] The apparatus according to Example 16, wherein one or more memories store further computer-executable instructions that, when executed by the one or more processors, control the one or more processors to cause the process chamber to maintain a plasma volume pressure greater than 1 Torre. [Example 21] The apparatus according to Example 16, wherein one or more memories store further computer-executable instructions that, when executed by the one or more processors, control the one or more processors to cause the process chamber to maintain a plasma volume pressure of 1 to 3 tors.

Claims

1. It is a device, The process chamber comprises, A window comprising a dielectric material that is transparent to radio frequency (RF) energy, having a first side and a second side opposite to the first side, A collar assembly having an opening covered by the window and supporting the first side of the window, the collar assembly comprising an annular structure including one or more gaps, The apparatus comprises one or more RF coils positioned above the second side of the window, wherein, when viewed along a first axis perpendicular to the window, the radial distance between the outermost part of the one or more RF coils and the innermost part of the conductive portion of the color assembly, which is perpendicular to the first axis and intersects with a first reference plane between the first side of the window and the one or more RF coils, is 40 mm or more.

2. The apparatus according to claim 1, wherein one or more coils include a total number of turns of 4 or less.

3. The apparatus according to claim 1, wherein one or more coils include a total number of turns of 3 or less.

4. The apparatus according to claim 1, wherein the diameter of the window is less than 350 mm.

5. The apparatus according to claim 1, further comprising a housing mechanically coupled to the color assembly, wherein one or more RF coils are located within the internal volume of the housing.

6. The apparatus according to claim 1, wherein the one or more gaps contain air.

7. The apparatus according to claim 1, wherein one or more gaps include a dielectric material.

8. The apparatus according to claim 1, further comprising one or more cooling structures that direct air toward the window.

9. The apparatus according to claim 1, wherein the window has a thickness of 20 mm to 25 mm.

10. The apparatus according to claim 1, wherein the opening has a diameter of 350 mm to 400 mm.

11. The apparatus according to claim 1, wherein the dielectric material has a dielectric constant of less than 10.

12. The apparatus according to claim 1, wherein the dielectric material is aluminum nitride, aluminum oxide, or both.

13. The apparatus according to claim 1, wherein the process chamber further comprises a shower head positioned below the window.

14. The apparatus according to claim 1, wherein the process chamber further comprises a base configured to support a substrate.

15. The apparatus according to any one of claims 1 to 14, further comprising one or more processors and one or more memories connected to the one or more processors, wherein the one or more memories store computer executable instructions, and when the computer executable instructions are executed by the one or more processors, A first process gas containing hydrogen gas is introduced into the plasma volume below the window. An apparatus that controls one or more processors to ignite a plasma using the first process gas, the plasma being generated by supplying power to one or more RF coils.

16. A computer-executable instruction for the apparatus according to claim 15, wherein, when executed by one or more processors, the instruction controls one or more processors to cause the first process gas to flow into the plasma volume and to cause the first process gas to flow into the plasma volume without accompanying helium flow.

17. The apparatus according to claim 15, wherein the plasma is inductively coupled plasma.

18. The apparatus according to claim 17, wherein one or more memories store further computer-executable instructions that, when executed by the one or more processors, control the one or more processors to transition the plasma into an inductively coupled plasma with a power of one or more RF coils less than 1000 W.

19. The apparatus according to claim 15, wherein one or more memories store further computer-executable instructions that, when executed by the one or more processors, control the one or more processors to cause the process chamber to maintain a pressure of the plasma volume greater than 1 Torre.

20. The apparatus according to claim 15, wherein one or more memories store further computer-executable instructions that, when executed by the one or more processors, control the one or more processors to cause the process chamber to maintain a pressure of 1 to 3 tors for the plasma volume.

Images