Patent Application
20250112062
The present disclosure relates to systems and methods for RF power path symmetry and configuration, and in some examples to geometric componentry configurations for symmetric RF power path and gas flow symmetry in multi-station process modules in semiconductor manufacturing applications.
Conventional multi-station substrate processing chambers that employ powered pedestals typically use a variety of component configurations to provide RF power. A conventional RF power path configuration is typically constrained by what components can fit next to or within external chamber hardware. The geometric configuration of RF power components can sometimes be variable with excessive or unacceptable tolerance levels and/or be unsymmetrical with respect to a substrate processing station.
External chamber hardware can include process gas exhaust lines, valving componentry, and a number of filters and enclosures for RF matching circuits, and so forth. Conventional configurations of exhaust lines, for example, can make access to lower chamber hardware difficult. The lower portions of some process stations are crowded which can make adding or configuring new hardware and RF power componentry difficult. In particular, some lower chamber hardware is especially difficult to work on because of a pedestal lift orientation which is dictated by the gas line geometry and location. Conventional configurations of external chamber hardware can significantly impede the creation of common geometric outlays of RF power componentry and the establishment of symmetrical RF power paths.
The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
In some examples, a multi-station process tool comprises a plurality of process chambers, each process chamber located at a station of the multi-station process tool; and a RF power path component associated with each station of the multi-station process tool, the RF power path component geometrically positioned and oriented such that, when energized, a symmetric RF power path is created with respect to a symmetry axis of the multi-station process tool.
In some examples, the symmetry axis is located at a center of the multi-station process tool. In some examples, the center of the multi-station process tool is defined by an axis of a spindle motor of the multi-station process tool.
In some examples, the RF power path component includes an RF component enclosure.
In some examples, the multi-station process tool of claim 1 includes a quad station process module (QSM) having a four stations, each station including a process chamber.
In some examples, a geometric position and orientation of a first RF power path component in relation to a first station of the four stations of the QSM, is symmetrical with a geometric position and orientation of a second RF power path component in relation to a second station of the four stations of the QSM.
In some examples, the geometric position and orientation of a first non-RF component in relation to the first station, is symmetrical with the geometric position and orientation of a second non-RF component in relation to the second station of the QSM.
In some examples, an asymmetry of the RF power path component or non-RF component is common to each station of the multi-station process tool.
In some examples, the multi-station process tool further comprises a foreline assembly including four inlets each connectable to a chamber port of a station of the QSM; an outlet connectable directly or indirectly to a vacuum source; a first foreline bifurcation disposed proximate an outlet of the foreline assembly; two second foreline bifurcations, each disposed between the first foreline bifurcation and a respective pair of the four inlets; and the first and second foreline bifurcations dividing the foreline assembly into three sections, a first section extending from the four inlets to the two second foreline bifurcations, a second section extending from the two second foreline bifurcations to the first foreline bifurcation, and a third section extending from the first bifurcation to the outlet of the foreline assembly.
In some examples, a respective diameter of a foreline in each section increases stepwise at a respective bifurcation in a direction of gas flow from at least one of the four inlets to the outlet of the foreline assembly; and is constant within a respective section of the foreline assembly.
In some examples, a diameter of a foreline in the first section is in a range 38.1 mm (approximately 1.5 inches) to 63.5 mm (approximately 2.5 inches), a diameter of a foreline in the second section is in the range 63.5 mm (approximately 2.5 inches) to 88.9 mm (approximately 3.5 inches), and a diameter of a foreline in the third section is in the range 88.9 mm (approximately 3.5 inches) to 114.3 mm (approximately 4.5 inches).
In some examples, the diameter of the foreline in the first section is 50.8 mm (approximately 2 inches), the diameter of the foreline in the second section is 76.2 mm (approximately 3 inches), and the diameter of the foreline in the third section is 101.6 mm (approximately 4 inches).
In some examples, the multi-station process tool further comprises a T-piece connector provided at each of the two second bifurcations.
In some examples, the T-piece connector includes outwardly converging conical sections that transition the diameter of a foreline in the first section to the diameter of a foreline in the second section.
In some examples, a separation distance between the T-piece connector and an underside of the QSM is configured to accommodate an RF power path component between the T-piece connector and underside of the QSM.
Some embodiments are illustrated by way of example and not limitation in the views of the accompanying drawing:
The description that follows includes systems, methods, techniques, instruction sequences, and computing machine program products that embody illustrative embodiments of the present disclosure. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of example embodiments. It will be evident, however, to one skilled in the art that the present disclosure may be practiced without these specific details.
A portion of the disclosure of this patent document may contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to any data as described below and in the drawings that form a part of this document: Copyright Lam Research Corporation, 2019-2021, All Rights Reserved.
A substrate processing system may be used to perform deposition, etching and/or other treatment of substrates such as semiconductor wafers. During processing, a substrate is arranged on a substrate support in a processing chamber of the substrate processing system. During etching or deposition, gas mixtures including one or more etch gases or gas precursors, respectively, are introduced into the processing chamber and plasma may be struck using RF power to activate chemical reactions.
The substrate processing system may include a plurality of substrate processing tools arranged within a fabrication room. Each of the substrate processing tools may include a plurality of process modules. Typically, a substrate processing tool includes up to six process modules.
Referring now to
The transfer mechanism may also be stacked to provide two or more transfer systems between the substrate processing tools 308 and 304. Transfer stage 312 may also have multiple slots to transport or buffer multiple substrates at one time.
In the configuration 300, the first substrate processing tool 304 and the second substrate processing tool 308 are configured to share a single equipment front end module (EFEM) 332.
Examples of the present disclosure may be deployed in a multi-station process module or process chamber, such as a QSM. In some examples, as shown in
A VTM 516 and an EFEM 510 may each include one of the transfer robots 502/504. The transfer robots 502/504 may have the same or different configurations. In some examples, the transfer robot 502 is shown having two arms, each having two vertically stacked end effectors. The robot 502 of the VTM 516 selectively transfers substrates to and from the EFEM 510 and between the process modules 508. The robot 504 of the EFEM 510 transfers substrates into and out of the EFEM 510. In some examples, the robot 504 may have two arms, each arm having a single end effector or two vertically stacked end effectors. A system controller 506 may control various operations of the illustrated substrate processing tool 500 and its components including, but not limited to, operation of the robots 502/504, and rotation of the respective indexers of the process modules 508, and so forth.
The tool 500 is configured to interface with, for example, each of the four QSMs 508. Each QSM 508 may have a single load station accessible via a respective slot 512. Other arrangements are possible. In the illustrated manner, two of the QSMs 508, each having a single load station, is coupled to a side 514 of the VTM 516. The EFEM 510 may be arranged at least partially between two of the process modules 508.
During substrate processing in a QSM 508, processing gases enter the module to assist in creating a plasma, for example. The gases then exit the process module 508. The expulsion of exhaust gases may be performed by a vacuum or exhaust line, also referred to as a foreline or foreline assembly in this specification. One of more forelines in a foreline assembly may be situated underneath each QSM 508 in the processing tool 500 and be connected to a vacuum source to expel gases from the QSM 508. Each foreline of a foreline assembly may serve to vent gasses from a respective station 518 in a QSM 508.
Each station 608 includes a respective lift pin actuator assembly 612 which can move lift pins upward and unseat a wafer during wafer transfer. The QSM 600 includes a spindle 602 that can transfer wafers from one wafer support 610 to another. The spindle 602 may be driven by a spindle motor 704 visible more clearly in
For illustrative purposes,
Plasma 1302 may be created within a processing zone 1330 of the vacuum chamber 1300 utilizing one or more process gases to obtain a wide variety of chemically reactive by-products created by the dissociation of the various molecules caused by electron-neutral collisions. The chemical aspect of etching involves the reaction of the neutral gas molecules and their dissociated by-products with the molecules of the to-be-etched surface and producing volatile molecules, which may be pumped away. When a plasma is created, the positive ions are accelerated from the plasma across a space-charge sheath separating the plasma from chamber walls to strike the substrate surface with enough energy to remove material from the substrate surface. The process of using highly energetic and chemically reactive ions to selectively and anisotropically remove materials from a substrate surface is called reactive ion etch (RIE). In some examples, the vacuum chamber 1300 may be used in connection with PECVD or PEALD deposition processes.
A controller 1316 manages the operation of the vacuum chamber 1300 by controlling the different elements in the chamber, such as RF generator 1318, gas sources 1322, and gas pump 1320. In one embodiment, fluorocarbon gases, such as CF4 and C4F8, are used in a dielectric etch process for their anisotropic and selective etching capabilities, but the principles described herein may be applied to other plasma-creating gases. The fluorocarbon gases are readily dissociated into chemically reactive by-products that include smaller molecular and atomic radicals. These chemically reactive by-products etch away the dielectric material.
The vacuum chamber 1300 illustrates a processing chamber with an upper (or top) electrode 1304 and a lower (or bottom) electrode 1308 in an RF power path. The upper electrode 1304 may be grounded or coupled to an RF generator (not shown), and the lower electrode 1308 is coupled to the RF generator 1318 via a matching network 1314. The RF generator 1318 provides an RF signal between the upper electrode 1304 and the lower electrode 1308 to generate RF power in one or multiple (e.g., two or three) different RF frequencies. According to a desired configuration of the vacuum chamber 1300 for a particular operation, at least one of the multiple RF frequencies may be turned ON or OFF. In the embodiment shown in
The vacuum chamber 1300 includes a gas showerhead on the top electrode 1304 to input process gas into the vacuum chamber 1300 provided by the gas source(s) 1322, and a perforated confinement ring 1312 that allows the gas to be pumped out of the vacuum chamber 1300 through a foreline of a foreline assembly (for example) by a gas pump 1320. In some example embodiments, the gas pump 1320 is a turbomolecular pump, but other types of gas pumps may be utilized.
When substrate 1306 is present in the vacuum chamber 1300, silicon focus ring 1310 is situated next to substrate 1306 such that there is a uniform RF field at the bottom surface of the plasma 1302 for uniform etching (or deposition) on the surface of the substrate 1306. The embodiment of
As used herein, the term “substrate” indicates a support material upon which, or within which, elements of a semiconductor device are fabricated or attached. A substrate (e.g., substrate 106) may include, for example, wafers (e.g., having a diameter of 100 mm, 150 mm, 200 mm, 300 mm, 450 mm, or larger) composed of, for example, elemental-semiconductor materials (e.g., silicon (Si) or germanium (Ge)) or compound-semiconductor materials (e.g., silicon germanium (SiGe) or gallium arsenide (GaAs)). Additionally, other substrates include, for example, dielectric materials such as quartz or sapphire (onto which semiconductor materials may be applied). Example substrates include blanket substrates and patterned substrates. A blanket substrate is a substrate that includes a low-surface (or planar) top surface. A patterned substrate is a substrate that includes a high-surface (or structured) top surface. A structured top surface of a substrate may include different high-surface-area structures such as 3D NAND memory holes or other structures.
Each frequency generated by the RF generator 1318 may be selected for a specific purpose in the substrate manufacturing process. In the example of
In another embodiment, a 60 MHz RF power is used on the upper electrode 1304 to get ultra-low energies and very high density. This configuration allows chamber cleaning with high-density plasma when substrate 106 is not in the vacuum chamber 1300 while minimizing sputtering on the electrostatic chuck (ESC) surface. The ESC surface is exposed when substrate X06 is not present, and any ion energy on the surface should be avoided, which is why the bottom 2 MHz and 27 MHz power supplies may be off during cleaning.
In an example embodiment, the vacuum chamber 1300 further includes a sensor 1328 which may be placed between the matching network 1314 of the RF generator 1318 and the lower electrode 1308. The sensor 1328 may include a voltage-current (or V-I) sensor configured to generate a plurality of signals (e.g., sensed data) that are indicative of at least one signal characteristic of RF signals generated by the RF generator 1318 at a corresponding plurality of time instances. For example, the V-I sensor may generate a plurality of signals that are indicative of one or more of the following signal characteristics of RF signals: voltage, current, phase, delivered power, and impedance. In some aspects, the plurality of signals generated by the sensor 1328 at the corresponding plurality of time instances may be stored (e.g., in on-chip memory of controller 1316 or the sensor 1328) and later retrieved (e.g., by the controller 1316) for subsequent processing. In other aspects, the plurality of signals generated by the sensor 1328 at the corresponding plurality of time instances may be automatically communicated to the controller 1316 as they are generated.
As discussed above, conventional configurations of external chamber hardware can significantly impede the creation of common geometric outlays of RF power componentry and the establishment of symmetrical RF power paths. To that end, examples of the present disclosure are directed to providing geometric componentry configurations for symmetric RF power path and gas flow symmetry, especially in multi-station process modules in semiconductor manufacturing applications. RF power path symmetry, or commonality, can be important for uniformity of wafer processing in multi-station processing tools, such as a QSM as described herein.
In some examples, providing RF power path symmetry across stations of a QSM for example may not necessarily mean providing “true” symmetry for (or within) each station, but simply that any asymmetry in a given RF power path is commonly distributed or shared by each station i.e., is common to each station. In these examples, the RF power path may be said to be symmetric in the sense that each station is commonly asymmetric.
An asymmetry that is not commonly shared across stations, or even an asymmetry in RF power path generally, can be very disruptive in substrate manufacturing processes. RF frequencies in excess of 27 MHz, for example 40 MHz, 60 MHz, or even 100 MHz, have a wavelength which is not considered long compared to the hardware or system size. A given physical asymmetry between stations in the geometric location of an RF power generator is “relatively” much higher at such small wavelengths as compared to the wavelengths associated with lower RF power, for example. In current processes that employ very high frequencies, the ability to create an asymmetric RF power path becomes increasingly likely. Moreover, at such high frequencies, non-linear circuit elements to include the plasma, for example, can lead to harmonic frequency generation and the prevalence of harmonics at multiples of the fundamental frequency make the challenge to create symmetry even more difficult.
Some examples seek to provide a symmetric RF power path with respect to a chamber or tool center, for example the spindle 602 at the center of the QSM 600 described above. In such examples, the spindle 602 serves as an axis of symmetry. Optimizing or improving an RF power path symmetry (or common asymmetry) can increase the ability to establish station to station matching for RF power and film properties. The symmetric geometric placement and configuration of RF power path componentry, as described herein, seek to make this possible.
Some examples herein are directed to establishing gas flow symmetry in a multi-station processing module. Some examples include a foreline assembly configured to enable gas flow symmetry across stations. Some example configurations of chamber components combine aspects of RF power path symmetry and gas flow symmetry. Example components may include a foreline, a foreline assembly, a valve or valving component, or an RF power path component such as an RF filter or RF component enclosure. Example component configurations enabling a RF power path symmetry, a gas flow symmetry, and/or a combined RF power path and gas flow symmetry may include one or more symmetric geometric configurations of components. The symmetric configuration of components may include components common to each station of a multi-station processing module.
With reference again to
It may be noted that the illustrated configuration of the foreline assembly 606 allows room for the orientation of the lift pin actuator assemblies 612 relative to the axis of the spindle 602 (or spindle motor 704) to remain the same i.e., they follow an imaginary concentric ring around the spindle 602 in the same direction. The (lower) outlet 616 of the foreline assembly 606 is connectable directly or indirectly to a vacuum source 604 and the control valve 614. The QSM 600 may include various components and supply lines 702, connectors 706, control wiring 708, and other modules 710 to supply the QSM 600, as shown. Other componentry and QSM arrangements are possible.
It will be noted that the geometric position and orientation of each RF component enclosure 611, within its own QSM quadrant or in relation to its own station 608, is symmetrical to the geometric position and orientation of another RF component enclosure within its own respective quadrant or station 608. In other words, each quadrant is may be said to be “clocked” around 90 degrees with respect to an adjacent quadrant, but in all other respects the geometric positions and orientations of the respective RF component enclosures within each quadrant are the same. In this sense, the geometric outlays of the RF component enclosures may be said to be symmetrical. The 90 degree “clocking” of the quadrants occurs around the axis of the spindle 602 or spindle motor 704 which represents an axis of symmetry accordingly.
The symmetrical outlay of RF componentry may be applied to other components in an RF power path disposed externally or underneath a QSM 600. For example, component such as RF power generators or filters. Some examples apply geometric symmetry to non-RF componentry. For example, it will be noted that the geometric position and orientation of each lift pin actuator assembly 612, within its own QSM quadrant or in relation to its own station 608, is symmetrical to the geometric position and orientation of another lift pin actuator assembly within its own respective quadrant or station 608.
In some examples, each quadrant of the QSM may have a local “asymmetry” and yet the QSM remain “symmetrical” overall in that the local asymmetry is rendered common to each quadrant or station. For example, let us assume a mounting bracket for a RF component enclosure 611 is manufactured with an error or design fault that causes a component within the enclosure 611 to be misaligned slightly. Let us assume the misalignment ordinarily would cause an unhelpful disturbance in an RF flux applied to the QSM 600 and perhaps even lead to manufacturing errors. In being commonly positioned and oriented, however, the error in each RF component enclosure 611 is equally distributed, as it were, and is rendered common to each quadrant. If needed, a single process accommodation can be made for this error, even though the defect occurs in four places. In this sense a QSM “symmetry” is created which, in some examples, enables consistency in manufacturing processes and conditions across each of the different QSM stations 608 even though a given component of the QSM may have a local defect, or misalignment. Aspects such as predictability, uniformity of output, and consistency of process can be key issues in semiconductor manufacturing, especially when operating at the high frequencies discussed above.
In some examples, the ability to derive this functionality and RF power path symmetry is made possible by the geometric configuration of a foreline assembly 606. In some examples, the geometric configuration is open and symmetrical. For example,
In some examples, the forelines in a foreline assembly 606 include three bifurcations. For example, a first or main bifurcation 902 is provided proximate the outlet 616. At the first bifurcation 902, a relatively large diameter pipe section joins two relatively smaller pipe sections 908, as illustrated in the example of
Two second bifurcations 904 of the foreline assembly are disposed between the first bifurcation 902 and respective pairs of the inlets 712, as shown. Only one of the two second bifurcations 904 is fully visible in the view of
A diameter of a foreline in the first section 906 may be in the range 38.1 mm (approximately 1.5 inches) to 63.5 mm (approximately 2.5 inches). A diameter of a foreline in the second section 908 may be in the range 63.5 mm (approximately 2.5 inches) to 88.9 mm (approximately 3.5 inches). A diameter of a foreline in the third section 910 may be in the range 88.9 mm (approximately 3.5 inches) to 114.3 mm (approximately 4.5 inches). In the illustrated example, a 2-3-4 foreline assembly 606 is shown, denoting the use of a 2-inch line in the first section 906, a 3-inch line in the second section 908, and a 4-inch line in the third section 910 of the foreline assembly 606. Other line configurations are possible. In some examples, the diameter of each line in each section 906, 908 and 910 between an inlet 712 or a connector is substantially uniform throughout.
In some examples, a T-piece connector 912 is provided at each second bifurcation 904. An example T-piece connector 912 may include two outwardly converging conical sections, as shown, that transition the diameter of the 3-inch foreline to the 2-inch foreline (or vice versa in the direction of exhaust gas flow). In some examples, a position of or a separation distance between the T-piece connector 912 and an underside of a QSM 600 may be selected to accommodate other components, for example a lift pin actuator assembly 612, an RF component enclosure 611, a spindle motor 704, an mDSC motor, or an eDSC motor.
In the first section 906, the foreline assembly 606 includes four forelines that each include three substantially right-angled elbows 914 disposed at intervals along the forelines. The elbows are provided between each inlet 712 and a respective second bifurcation 904. In some examples, the forelines in the first section 906 are generally continuous and no separable joints or unions are provided. Other arrangements are possible.
In the second section 908, the foreline assembly 606 includes two forelines that each include one substantially right-angled elbow 916 disposed between the first 902 and second 904 bifurcations. In some examples, a separable union 918 is provided at or towards an upper end of each elbow 916. Each union 918 may include, as shown, two opposed flanges 920 that can be bolted together to join each elbow 916 to an exit port of the T-piece connector 912. The flanges 920 lie in horizontal planes and their positioning above an elbow 916 creates a symmetry for both halves of the second section 908 in the sense that different “right-handed” or “left-handed” elements in the second section 908 are avoided. The horizontal orientation of the flanges 920 also allow an operator ease of access to nuts or bolts passing vertically through the flanges 920 to secure the union 918 since the nuts or bolts can be accessed from directly underneath the QSM 600, as opposed to requiring a lateral space in order to do so. This horizontal orientation of the union 918 and flanges 920, together with the aforementioned improved clearance around the spindle motor 704, further assist ease of operator maintenance of a QSM 600.
The third section 910 of the foreline assembly 606 may include the plenum chamber 922 referenced above and a relatively short length of large diameter foreline extending from the plenum chamber 922 to the outlet 616 of the foreline assembly 606.
With reference to
Some embodiments include methods. With reference to
In some examples, the symmetry axis is located at a center of the multi-station process tool. In some examples, the center of the multi-station process tool is defined by an axis of a spindle motor of the multi-station process tool.
In some examples, the RF power path component includes an RF component enclosure.
In some examples, the multi-station process tool includes a quad station process module (QSM).
In some examples, the method 1200 further comprises, at operation 1206, configuring the QSM for a symmetric gas flow, the configuring of the QSM comprising, at least: fitting a foreline assembly to the QSM, the foreline assembly including: four inlets each connectable to a chamber port of a station of the QSM; an outlet connectable directly or indirectly to a vacuum source; a first foreline bifurcation disposed proximate an outlet of the foreline assembly; two second foreline bifurcations, each disposed between the first foreline bifurcation and a respective pair of the inlets; and the first and second foreline bifurcations dividing the foreline assembly into three sections, a first section extending from the four inlets to the two second foreline bifurcations, a second section extending from the two second foreline bifurcations to the first foreline bifurcation, and a third section extending from the first foreline bifurcation to the outlet of the foreline assembly.
In some examples, the method 1200 further comprises processing a substrate in the QSM using a symmetric RF power path and a symmetric gas flow in each station of the QSM.
Although examples have been described with reference to specific example embodiments or methods, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.
Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.
This application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 63/305,606, filed on Feb. 1, 2022, which is incorporated by reference herein in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2023/011285 | 1/20/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63305606 | Feb 2022 | US |
