Patent Application
20220122878
The present embodiments relate to a substrate processing system used in manufacturing semiconductor substrate, and more particularly, to a lift pin mechanism that is used for replacing a top ring and a mid ring used in a process module of the substrate processing system.
A typical substrate processing system used in processing a semiconductor substrate includes a substrate storage box (otherwise referred to as “substrate storage station” or a front opening unified pod (FOUP)), that is used to deliver and store substrates, an equipment front end module (EFEM) that interfaces between the FOUP and a first side of one or more loadlock chambers (otherwise referred to as “airlocks”), a vacuum transfer module coupled to a second side of the one or more airlocks and one or more process modules that are coupled to the vacuum transfer module. Each process module is used to perform a specific manufacturing operation, such as a cleaning operation, a deposition, an etching operation, a rinsing operation, a drying operation, etc. The chemistries and/or processing conditions used to perform these operations cause damage to some of the hardware components of the process module that are constantly exposed to the harsh conditions within the process module. These damaged or worn out hardware components need to be replaced periodically and promptly to ensure that these damaged components do not expose other underlying hardware components in the process module to the harsh conditions during semiconductor substrate processing. The hardware component maybe, for example, a top ring, such as an edge ring, that is disposed immediately adjacent to a semiconductor substrate within a process module. During an etching operation, the top ring, based on its location, may get damaged due to its continuous exposure to ion bombardment from plasma generated within the process module that is used in the etching operation. The damaged top ring needs to be replaced promptly to ensure that the damaged top ring does not expose other underlying hardware components, such as the remaining components of an electrostatic chuck or a pedestal, to the harsh process conditions. The hardware components that can be replaced are referred to herein as consumable parts.
The current process of replacing the damaged consumable part requires the consumable part, such as the top ring, to be accurately positioned along a horizontal coordinate plane (e.g., ring transfer plane) for hand-off to the lift pins within a process module. Due to very limited space within the process module, precise handing of the consumable part is especially important to ensure the hand-off occurs reliably.
It is in this context that embodiments of the invention arise.
Embodiments of the invention define a lift pin mechanism employed within a process module of a substrate processing system that is designed to remove and replace damaged hardware components, such as a top ring (e.g., edge ring) and a mid ring, of a process module disposed within the substrate processing system, without a need to break vacuum (i.e., expose the substrate processing system to Atmospheric condition). A damaged hardware component that can be replaced is also referred to herein as a consumable part. The substrate processing system includes one or more process modules, with each process module configured to perform a semiconductor substrate processing operation. As the consumable part in a process module gets exposed to the harsh chemicals and process conditions within, the consumable part gets damaged and needs to be replaced in a timely manner The damaged consumable part has to be replaced promptly so as to prevent compromising underlying hardware components of the process module.
The damaged consumable part (e.g., top/edge ring or mid ring) may be replaced without opening the substrate processing system by mounting a detachable ring storage station to the substrate processing system. The ring storage station is similar to a substrate storage station that provides the substrate for processing. The ring storage station includes a plurality of compartments stacked horizontally for receiving and storing the consumable parts (i.e., both new and used consumable parts). The ring storage station and the process module(s) are coupled to a controller to enable the controller to coordinate access to the ring storage station and the various process modules while the process modules are maintained in a vacuum state, so as to allow replacement of the consumable part in the respective process modules.
To provide easy access to the damaged consumable part, a process module of the substrate processing system is designed to include a lift pin mechanism. When engaged, the lift pin mechanism is configured to allow the consumable part to be moved from an installed position to a replacement position so that an end-effector of a robot available within the substrate processing system may be used to access and retrieve the raised consumable part from the process module. A replacement consumable part (i.e., new consumable part) is retrieved from the ring storage station and delivered to the process module and the lift pin mechanism is used to receive the new consumable part and lower it into position in the process module.
The design of the ring storage station and the substrate processing system is such that a need to open the substrate processing system to Atmospheric conditions in order to access the damaged consumable part, is eliminated. For example, the substrate processing system may include an equipment front end module (EFEM) maintained at Atmospheric condition. A first side of the EFEM may be coupled to one or more substrate storage stations (e.g., FOUPs) for transferring substrates into and out of the substrate processing system. In addition to substrate storage stations, the first side or a different side of the EFEM may be coupled to one or more ring storage stations. A second side of the EFEM may interface with a vacuum transfer module through one or more loadlock chambers, such as airlocks. One or more process modules may be coupled to the vacuum transfer module.
A robot of the EFEM may be used to transport the consumable part between the ring storage station and the airlock. In such implementations, the airlock acts as an interface by allowing the consumable part to be received from the EFEM while the airlock is maintained at Atmospheric condition. After receiving the consumable part, the airlock is pumped to vacuum, and a robot of the vacuum transfer module is used to move the consumable part to the process module. A robot of the vacuum transfer module is used to move the consumable part into the process module. A lift pin mechanism within the process module provides access to the consumable part by raising and lowering the consumable part, so that the replacement of the consumable part can be carried out by the robot of the vacuum transfer module in vacuum conditions.
The robot of the vacuum transfer module and the lift pin mechanism of the process module together allow precision delivery and retrieval of the consumable part thereby eliminating the risk of damage to any hardware components of the process modules during replacement of the consumable part. As the consumable part is being moved into the process module in a controlled manner, the time required to recondition the process module to bring it to an active operation state after replacement of the damaged consumable part, is substantially reduced.
In alternate implementations, the ring storage station may be maintained at vacuum and coupled to the process module directly or through the vacuum transfer module of the substrate processing system. The robot of the vacuum transfer module may be used to move the consumable part between the ring storage station and the process module without breaking vacuum, so that the consumable part may be replaced without risk of contamination. Consequently, the time required to recondition the process module to bring to an active operation state after replacement of the damaged consumable part, is substantially reduced.
In one embodiment, a lift pin mechanism is disclosed. The lift pin mechanism is employed within a process module of a substrate processing system and is used for exchanging consumable parts (e.g., top ring or mid ring) of the process module. The lift pin mechanism includes a plurality of lift pins that are distributed uniformly along a circumference of a lower electrode (e.g., a pedestal or an electrostatic chuck) defined in the process module. Each lift pin includes a top member and a bottom member. The top member is separated from the bottom member by a collar defined by a chamfer The top member is configured to extend through a sleeve defined in a housing within a body of a lower electrode disposed in the process module and engage with an underside surface of a top ring used in the process module. The collar of the lift pin is configured to engage with a bottom surface of the sleeve. A top surface of the sleeve is configured to engage with a bottom side of the mid ring, when the plurality of lift pins is activated. An actuator is coupled to each of the plurality of lift pins. The actuators are connected to an actuator drive that provides power to drive the actuators. A controller is coupled to the actuator drive and is configured to provide control signals to control movement of the plurality of lift pins.
In another embodiment, a process module used within a substrate processing system, is disclosed. The process module includes a top electrode with a plurality of outlets distributed uniformly along a horizontal plane. The plurality of outlets is connected to a process chemistry source and is configured to provide process chemistry to the process module for generating plasma. The top electrode is electrically grounded. A lower electrode is disposed opposite to the top electrode and is configured to support the substrate received for processing. The lower electrode is connected to a power source to provide power to generate the plasma. The lower electrode includes a bottom ring disposed within a body proximal to an outer edge. A housing extends from a top surface of the bottom ring downward into a body of the bottom ring. The housing is configured to house a sleeve. A mid ring is disposed immediately above the bottom ring and is aligned with the bottom ring. The mid ring includes a channel that extends vertically from a top surface to a bottom surface of the mid ring. A top ring is disposed immediately above the mid ring and aligned with the mid ring such that a top surface of the top ring is co-planar with a top surface of the substrate, when the substrate is received on the lower electrode. A lift pin mechanism is defined in the body of the lower electrode. The lift pin mechanism includes a plurality of lift pins. Each lift pin includes a top member and a bottom member. The top member is separated from the bottom member by a collar defined by a chamfer. The plurality of lift pins are distributed uniformly along a circumference of the lower electrode so as to align with the bottom ring, the mid ring and the top ring. An actuator is coupled to each of the lift pins. The actuators of the plurality of lift pins are connected to an actuator drive that provides power to drive the actuators.
Other aspects of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings.
Embodiments of the disclosure define a lift pin mechanism within a process module of a substrate processing system that is used to process a semiconductor substrate. The lift pin mechanism is used to replace a consumable part, such as a top ring (i.e., an edge ring), a mid ring, that is disposed adjacent to the semiconductor substrate within the process module. The substrate processing system includes one or more process modules that are used to perform process operations on a semiconductor substrate. Some of the process operations that can be performed in the different process modules include a cleaning operation, a deposition, an etching operation, a rinsing operation, a drying operation, etc. A ring storage station is mounted to the substrate processing system and is used to deliver consumable part, such as a top ring, during replacement of the consumable part in the one or more process module. The consumable part, disposed immediately adjacent to a substrate received in a process module, is exposed to the harsh chemistries in the process module. As a result, the consumable part gets damaged due to constant exposure and is promptly replaced using the lift pin mechanism implemented in the substrate processing system. The replacement of the consumable part is performed in a controlled manner so as to avoid any risk of contamination to the components of the process module or the substrate processing system.
The lift pin mechanism employed in a process module is used to provide access to a used and damaged consumable part, and a robot available within the substrate processing system is used to retrieve the used consumable part from the process module and replace with a new consumable part. In some implementations, in addition to replacing the consumable part, such as a top ring, additional consumable part, such as a mid ring may also be replaced using the lift pin mechanism used for replacing the top ring. The mid ring, disposed immediately below the top ring, may be exposed to some of the contaminants that are generated from the harsh chemicals in the process chamber. Such contaminants may make their way onto a top surface of the mid ring during operation of the process module (e.g., during tuning of the top ring). The contaminants may damage the top surface of the mid ring or may deposit on the top surface making the top surface uneven. The uneven top surface may result in sub-optimal mating of the top ring to the mid ring, which can lead to further damage due to additional contaminants making its way to the surface of the mid ring. As a result, the mid ring may have to be replaced from time to time so as to provide reliable support to the top ring and to prevent damage to underlying hardware components. Due to its location below the top ring, the mid ring may need to be replaced less frequently than the top ring. For instance, the top ring may need to be replaced after exposing the top ring for about 150 to about 300 radio frequency (RF) hours while the mid ring may have to be replaced after about 750 to about 1500 RF hours. Irrespective of how frequently the mid ring needs to be replaced, the various implementations of the lift pin mechanism of the process module described herein provide ways to replace the mid ring in a manner similar to the replacement of the top ring.
Traditional design of a substrate processing system required the substrate processing system to be opened in order to access and replace the consumable part, such as the top ring, within a process module. Opening of the substrate processing system required taking the substrate processing system offline and purging the substrate processing system to atmospheric condition to allow access to the process modules. Once the substrate processing system is opened, a trained technician would manually remove and replace the consumable part from a process module. Upon replacement of the consumable part, the substrate processing system had to be conditioned so that the semiconductor substrate can be processed. Since the semiconductor substrates are valuable products, extreme care has to be taken when conditioning the substrate processing system. The conditioning would require cleaning the substrate processing system, pumping the substrate processing system to vacuum, conditioning the substrate processing system and qualifying the substrate processing system using test runs. Each of these steps requires considerable time and effort. In addition to the time required at every step to condition the substrate processing system, additional delays may be experienced when problems are encountered at one or more of the steps during the conditioning of the substrate processing system.
Some of the problems commonly encountered during the conditioning of the substrate processing system may include misalignment of the consumable part during replacement, damage to the new consumable part when replacing a damaged or used consumable part, damage to other hardware components in the process module during retrieval or replacement of the consumable part, substrate processing system not achieving vacuum after pumping, substrate processing system not achieving process performance, etc. Based on the severity of each problem, additional time and effort may have to be expended, further contributing to delay of bringing the substrate processing system online, directly impacting the profit margin for a manufacturer.
Additionally, most of the focus in the traditional process was to replace top rings (i.e., edge rings) and was not directed toward replacing a mid ring. As the mid ring is disposed below the top ring, it was deemed that replacing the top ring was sufficient to provide optimal processing conditions and that replacing the mid ring was not necessary. However, as newer designs of the top ring allow the top ring to be tuned (i.e., by raising the top ring), the top surface of the mid ring is getting damaged due to contaminants from the process module making their way to the top surface of the mid ring. As a result, it is desirable to replace the mid ring from time to time to allow the top ring to have a reliable surface to rest on when received in the process module. In the various implementations described throughout this application, the mid ring is a replaceable component and the top ring is a tunable and replaceable component.
The lift pin mechanism of the process module provides the capability to replace the top ring as well as the mid ring. The lift pin mechanism is configured to raise both the top and the mid rings so that an end effector of a robot within the substrate processing system can reach in and retrieve the top and the mid rings. In some implementations, the top and the mid rings are moved separately so that the end effector of the robot can retrieve and replace the top ring and the mid ring one at a time. Alternately, the lift pin mechanism allows the top and the mid rings to be moved simultaneously in a manner that allows the top ring to be removed first and the mid ring removed next. In yet other implementations, the lift pin mechanism may move both the top and the mid rings together and the end effector (i.e., arm) of the robot is designed to remove both of the rings together.
In some implementations, the top ring is designed to include a set of grooves (e.g., v-shaped or u-shaped grooves) on an underside surface to allow the top ring to properly align with the lift pins of the process module. These grooves provide “anti-walk” feature, as the grooves are engaged by the lift pins and the top ring is held in place, thereby preventing the top ring from “walking” or sliding. The underside groove feature of the top ring and the use of robot ensure minimal damage to the hardware components of the process module and to the top ring during replacement of the top ring. Further, timely replacement of the consumable parts in a controlled manner reduces the amount of time required to condition the substrate processing system, thereby increasing quality and yield of semiconductor components defined on the semiconductor substrate.
With the general understanding of the inventive implementations, details of specific implementations will be discussed with reference to the various drawings.
In some implementations, in addition to loadports 101a-101c for receiving wafer stations, one or more additional loadports may be defined to receive a ring storage station (not shown). The ring storage station is configured to receive and store consumable parts, such as top rings (also referred to herein as “edge ring” as it is disposed adjacent to an outer edge of the substrate within the process module) and mid rings. The loadports to receive ring storage station may be defined on the same side of the EFEM as the loadports 101a-101c or on a different side of the EFEM 102. In alternate implementations, one or more of the loadports 101a-101c may be configured to receive ring storage station while the remaining loadports may be used to receive the wafer station(s).
The VTM 104 is operated under vacuum so as to minimize exposure of the semiconductor substrate surface to atmospheric air as the semiconductor substrate is moved from one process module into another. Since, the VTM 104 is operating under vacuum and the EFEM 102 is operating at Atmospheric condition, one or more loadlock chambers 110 are interfaced between the EFEM 102 and the VTM 104. The loadlock chamber 110 provides a controlled interface to allow the transfer of the semiconductor substrate from the wafer storage through the EFEM 102 to the VTM 104. In this embodiment, the robot within the EFEM 102 is used to deposit the semiconductor substrate into the loadlock chamber 110. A separate robot provided within the VTM 104 is used to retrieve the semiconductor substrate from the loadlock chamber 110 and transfer the semiconductor substrate into and out of process module (112-120). Due to its location, the loadlock chamber, in some embodiments, is also referred to as an “interfacing chamber” or an “airlock”. The loadlock chambers (i.e., airlocks) 110 may be selectively maintained in ambient condition or vacuum. For example, when the substrate is being moved between the wafer station and the airlock 110 via the EFEM 102, the airlock is maintained in ambient condition and when the wafer is being moved between the airlock 110 and the VTM 104, the airlock 110 is maintained in vacuum. Similar process may be used when transporting a consumable part between a ring storage station and the process module.
In some implementations, a load port to receive the ring storage station may be defined on a side of the EFEM where the airlock 110 is defined. In such implementations, the load port to receive a ring storage station may be defined above the airlock. The location of the airlock is not restricted to the sides or location noted herein but could also be located on a different side of the EFEM or below the airlock, etc.
One or more process modules 112-120 are integrated with the VTM 104 so as to allow the semiconductor substrate to move from one process module to another process module in a controlled environment (i.e., without breaking vacuum) maintained by the VTM 104. In some embodiments, the process modules 112-120 may be distributed uniformly around the VTM 104 and used to perform distinct process operations. Some of the process operations that can be carried out using the process modules 112-120 include etch operation, rinsing, cleaning, drying operation, plasma operation, deposition operation, plating operation, etc. By way of example, process module 112 may be used to perform a deposition operation, process module 114 may be used to perform a cleaning operation, process module 116 may be used to perform a second deposition operation, process module 118 may be used to perform an etch or removal operation, and so on. The VTM 104 with the controlled environment allows the semiconductor substrate to be transferred into and out of the process modules 112-120 without risk of contamination and the robot within the VTM 104 assists in transferring the semiconductor substrate into and out of the various process modules 112-120 that are integrated with the VTM 104.
The integrated substrate processing system of
In alternate implementation, the ring storage station may be mounted to any one of the process modules 112-120 or to the VTM 104 of the substrate processing system. In the implementation where the ring storage station is coupled to one of the process modules 112-120 or the VTM 104, the ring storage station 108 includes a mechanism, such as a pump mechanism, (not shown) to pump the ring storage station so as to maintain it at vacuum.
An isolation valve may be provided as an interface between the ring storage station and the EFEM, when the ring storage station is coupled to a side of the EFEM. The isolation valve is used to isolate the ring storage station. The isolation of the ring storage station may be useful during loading of the consumable parts onto the ring storage station. Similarly, isolation valve(s) may be used to interface between the ring storage station and the process module or the VTM 104, when the ring storage station is coupled directly to the process module or the VTM 104. Operation of the isolation valve is controlled to allow access to the consumable part in the process module and the ring storage station.
The ring storage station is a moveable, modular unit that is designed to be temporarily mounted to a module of the substrate processing system to complete the required operation of replacing the consumable part, such as the top ring (i.e., edge ring), or the mid ring, and dismounted once the required operation at the process module is completed. The dismounted ring storage station is either retracted or moved to a different module to proceed with the required operation of replacing the consumable part at a second process module.
The ring storage station includes a part buffer with a plurality of compartments for receiving and holding the consumable parts. Separate set of compartments may be defined in the ring storage station to store used consumable parts that are retrieved from a process module, and new consumable parts that are to be delivered to the process module. In one embodiment, an opening in the ring storage station and the size of the isolation valve defined at one or each of the modules (e.g., EFEM, airlocks, or process module) are designed to allow the movement of the consumable part into and out of the ring storage station.
Due to proximity of the consumable part to the semiconductor substrate in the process module and its continuous exposure to the harsh process conditions used during processing of the semiconductor substrate, the consumable part needs to be closely monitored and promptly replaced when the damage to the consumable part exceeds a predefined threshold level. In some implementations, the consumable part that is used in the process module discussed herein is a top ring (also referred to herein as an edge ring) that is tunable and/or replaceable. In addition to the top ring being a replaceable consumable part, in some implementations, a mid ring that is defined below the top ring within the process module may also need to be replaced. The mid ring, in these implementations, is a replaceable hardware component.
For example, in an etch process module, a top ring is disposed adjacent to the semiconductor substrate mounted on a chuck assembly to extend the process region of the semiconductor substrate. During the etching operation, the top ring is exposed to the ion bombardment from the plasma that is used to form features on a surface of the semiconductor substrate. For instance, during the etching operation, ions from the plasma hit the semiconductor substrate surface at an angle that is perpendicular to a plasma sheath formed in a process region defined above the semiconductor substrate, received in the process module. Over a course of time, as a result of continuous exposure to the plasma, a top surface of the top ring gets damaged. When layers of the top ring wear away due to ion bombardment, the edge of the semiconductor substrate is exposed causing the plasma sheath to roll along a contour of the semiconductor substrate edge. Consequently, the ions hitting the semiconductor substrate surface follow the contour of the plasma sheath thereby causing tilt features to be formed toward the edge of the semiconductor substrate surface. These tilt features would affect the overall yield of the semiconductor components formed on the semiconductor substrate.
To improve the yield, reduce edge exclusion region, and to avoid damage to any underlying components, the top ring is tuned by moving the top ring up so as to make the top surface of the top ring coplanar with the top surface of the substrate, when the surface is received for processing. An amount of tuning of the top ring is based on a thickness of the top ring and the amount of damage experienced at the top surface of the top ring. When the tuning of the top ring has exceeded a threshold level, the top ring needs to be promptly replaced. Further, when a damage (e.g., due to tuning of the top ring, due to contaminants generated within the process module, etc.) to the mid ring exceeds the threshold level, the mid ring also needs to be replaced to improve the yield and to prevent damage to the underlying hardware components. The replacement of the mid ring is carried out less frequently than the top ring.
After removing the damaged or used top ring and the mid ring from the process module, the robot of the EFEM 102 is used to transport a new top ring and a new mid ring from the ring storage station to the airlock 110 and the dedicated robot of the VTM is used to transport the new top ring and the new mid ring from the airlock 110 to the process module. Although some of the implementations are discussed herein with reference to the ring storage station being coupled to a side of the EFEM 102, the teachings can be extended to other implementations where the ring storage station is coupled to different modules (process modules 112-120 or VTM 104) of the substrate processing system 100.
The top ring and the mid ring may each be stored in separate ring storage stations and provided as and when the top ring and the mid ring need to be replaced. A lift pin mechanism (not shown) within the process module 118 provides access to the consumable part. The different parts and functionality of the lift pin mechanism will be discussed in more detail with reference to
Access to the ring storage station and the process module is coordinated using the different isolation valves and/or gates disposed between the different modules and between the EFEM and the ring storage station. For example, in one implementation, isolation valves and/or gates disposed between the EFEM and the ring storage station and between the VTM 104 and the one or more of the process modules 112-120, the robots of the EFEM 102 and the VTM 104, and the lift pin mechanism of the one or more process modules may all be operatively connected to a controller 122. The controller 122 may be a computer or may be communicatively connected to a computer 124 that can be used to provide input to coordinate operation of the isolation valves and/or gates, the airlocks, movement of the robots of the EFEM and the VTM, and the lift pin mechanism of the process module during retrieval and replacement of the consumable part.
The isolation valve defined between the ring storage station and the El-BM 102 may be used to isolate the ring storage station so that consumable parts may be loaded onto the ring storage station without affecting the processing of the substrate within the substrate processing system. Similarly, a second isolation valve defined between the VTM 104 of the substrate processing system 100 and a process module (112-120) where the consumable part needs to be replaced, is used to isolate the process module from the rest of the substrate processing system 100 so that the replacement of the consumable part within the process module can be easily carried out without affecting operation of other process modules of the substrate processing system 100. Providing the second isolation valve allows specific one of the process modules (any one of 112-120) to be taken off-line instead of the whole substrate processing system 100, while the remainder of the process modules (112-120) within the substrate processing system 100 may be allowed to continue processing the semiconductor substrate. Further, as only a specific process module (e.g., any one of 112-120) is brought off-line for replacing the consumable part(s), it would take considerably less time to restore the process module (112-120) and the substrate processing system 100 to a fully operational state. As a result, time taken for conditioning and qualifying operation of the substrate processing system 100 is much shorter.
In some implementations, when the consumable part, such as the top ring and/or the mid ring, needs to be replaced in more than one process module, the operation of the robots and the corresponding isolation valves within the substrate processing system 100 may be coordinated so that the consumable part may be replaced in a sequential manner In such embodiments, the time taken for replacing the consumable parts in a plurality of modules may be much shorter as the ring storage station and the process module(s) are selectively isolated, thereby allowing the remaining modules to continue with the substrate processing operations.
The various implementations discussed with reference to
The process module 118 also includes a lower electrode 133. The lower electrode 133 is configured to receive a semiconductor substrate 150 for processing. In one implementation, the lower electrode 133 is an electrostatic chuck (ESC). In another implementation, the lower electrode is a pedestal. In the implementation of
The process module 118 includes a lift pin mechanism 141 to enable the consumable part (i.e., top ring 200 and mid ring 300) to be moved from an installed position to a raised position. The lift pin mechanism 141 includes a plurality of lift pins 142 and actuators 143, which when activated, contacts and lifts the consumable part to a raised position. In one implementation, an actuator drive (not shown) is connected to the actuators 143 and provides the power to drive the actuators 143. In another implementation, the actuator drive may be integrated with the actuator. The actuator drive may be coupled to the controller 122 to control operation of the lift pin mechanism 141 during replacement of the consumable part. The controller 122, in turn, may be part of a computer 124 or may be communicatively connected to a computer 124. The computer 124 is used to provide inputs to control operation of the lift pin mechanism, when the consumable part needs to be replaced. The lift pin mechanism 141 will be discussed in more detail with reference to
After the consumable part has been replaced, the process module 118 may be conditioned before returning the process module 118 to active operation, in some implementations. The conditioning operation will take a shorter time as the replacement of the consumable part (e.g., top ring 200 and mid ring 300) was carried out in a controlled manner.
The top ring 200 and the mid ring 300 are defined adjacent to an outer sidewall of the wafer receiving component of the ESC/pedestal. In some implementations, the wafer receiving surface of the ESC, for example, is designed such that the substrate received on the top surface extends beyond an outer edge of the ESC. In these implementations, a portion of the mid ring 300 is disposed adjacent to the outer sidewall and below the portion of the substrate that extends from the outer edge of the ESC. In the example implementation of
In one implementation, a length of the top member of each lift pin is defined to be less than a distance between a top surface of the ESC and a replacement position defined by the ring transfer plane (RTP). In some other implementations, the length of the top member is defined to be equal to the distance between the top surface of the ESC and the RTP. In different implementations, the length of the top member is equal to or greater than or less than the length of the bottom member. In some implementations, the lift pins are made of sapphire. However, the material used for the lift pins are not restricted to sapphire but can use other materials without compromising the functionality of the lift pins.
The plurality of lift pins 142 of the lift pin mechanism 141 are configured to move the consumable part (both the top ring 200 and mid ring 300) between an installed position and a raised position so that the consumable part can be accessed by an arm of a robot when the consumable part needs to be replaced. The collar 145 is defined by a chamfer (i.e., a symmetrically disposed sloping transitional edge between the top and the bottom member). In some implementations, the chamfer is defined at about 45° angle. However, the angle of the chamfer is provided as an example and should not be considered restrictive. Other angles may also be considered for defining the chamfer. For example, in some implementations, the angle of the chamfer may be defined to be 30° or 25° or 50° or any other angle value so long as it is symmetrically disposed between the top and the bottom members, 142a, 142b.
The diameter of the top member is smaller than the diameter of the bottom member. The dimensions of the top and the bottom members of the lift pin are designed so that they can easily move through the channels and housing defined in the ESC. In one implementation, the diameter of the top member is about 40 mm and the diameter of the bottom member is about 60 mm with a chamfer defined between the two members. In this implementation, the channels defined in the bottom ring 234 and the mid ring 300 are sized to accommodate the lift pins. For instance, the size of the channel in the bottom ring may be defined to accommodate both the top and the bottom members of the lift pin while the size of the channel defined in the mid ring may be sized to accommodate the top member of the lift pin. In the above example dimensions of the top and the bottom members of the lift pin, the size of the channel defined in the bottom ring may be greater than 60 mm while the size of the channel in the mid ring may be between about 42 mm to about 58 mm or anywhere in-between. The dimensions provided for the top and the bottom members of the lift pins, and for the channels in the bottom and the mid rings are provided as an example and should not be considered restrictive. Other dimensions may also be envisioned for the top and the bottom members and the channels defined in the various rings (e.g., bottom and mid rings) are sized accordingly. It should be noted herein that the channels in the bottom ring and the mid ring are aligned with the lift pins so that the lift pins can easily extend through the respective channels in the bottom and the mid rings.
Referring back to
In some implementations, a band 235 made of ceramic material may be defined immediately below the bottom ring 234 such that the band 235 is disposed below an outer edge portion of the bottom ring 234 such that it is disposed between a second portion of the lift pin mechanism 141 and the cover ring 232. In some implementations, the band 235 is made of elastomer material, such as perfluorelastomer. Additional insulation material may be defined between the lift pin mechanism 141 and the band 235, in some implementations. The rings/bands are provided between the lift pin mechanism 141 and the chamber sidewall (not shown) of the process module chamber so as to insulate the lift pin mechanism 141.
When the lift pin mechanism is engaged to replace the top ring, each of the lift pins is extended out of a lift pin housing defined in the ESC, contact a groove defined in an underside of the top ring 200 and move the top ring to a first height. The first height is defined as a height that positions the top ring at the RTP. The first height, in one implementation, is defined as a distance between the top surface of the ESC and the RTP less the thickness of the thinnest portion of the top ring. In other implementations, the first height is defined to be a distance between the top surface of the top ring, when in the installed position, and the RTP. In some other implementations, the first height is defined to be less than a distance between the top surface of the ESC and the RTP. The RTP is defined as a height defined within the process module to which the top ring, for example, has to be raised so as to provide sufficient space for the arm of the robot to extend its end-effector into the process module, slide under the top ring to support the top ring and move the top ring out of the process module without the top ring or the arm of the robot hitting the chamber walls or any other hardware component of the process module.
When the mid ring is to be replaced, the lift pin is extended further so that the collar between the bottom member and the top member of the lift pin engages with a sleeve 236 defined in the bottom ring 234, and moves the sleeve 236 out of its housing. The sleeve 236 engages with the mid ring 300, and the bottom member of the lift pin with the sleeve 236 and the mid ring 300 continues to move up till the bottom member extends to a second height. The second height is defined to be a height to which the second member of the lift pin has to be moved up in order to raise the mid ring to the RTP. The second height, in some implementations, is defined to be a distance between the RTP and a surface on which the mid ring rests, when the mid ring is in the installed position. In some implementations, the second height is greater than the first height. As a result, the length of the bottom member, in such implementations, may be greater than the length of the top member.
Based on the first height and the second height to which the top and the bottom members of the lift pin 142 are respectfully being moved, the length of the top member may be equal to or greater than or less than the length of the bottom member. The actuators provide sufficient power to the lifts pins to enable the top and the bottom members to move the top ring and the mid ring to the RTP position defined for the process module so as to allow the robot to replace the consumable part—i.e., the mid ring and/or the top ring. Once the top ring has been moved to the RTP (i.e., top ring replacement position), the arm of the robot moves in and removes the used top ring from the process module 118 and replaces the used top ring with a new top ring. After the arm of the robot extends in to the process module to support the top ring and before the arm removes the top ring from process module, the lift pin is at least partially retracted so that the lift pin is not in the way of the arm and the top ring. A used mid ring is replaced with a new mid ring in a similar fashion.
The process of engaging the lift pins can also be used during tuning of the top ring. For tuning the top ring, the lift pin 142 is moved incrementally so that the lift pin carries the top ring to a different height so as to make the top surface of the top ring co-planar with the top surface of the ESC.
The plurality of lift pins 142 may be distributed along a horizontal plane throughout the ESC to allow the lift pins 142 to contact the consumable part at different points and provide kinematic support when moving the consumable part vertically to different heights in the process module. In some implementations, the plurality of lift pins may include a set of three lift pins that may be distributed uniformly along the radial axis so that they are equidistant from one another and are each at a distance from a center that is at least a radius of the top ring. The number of lift pins is not limited to three but could include more than three so long as the lift pins are able to provide kinematic support to the top ring when it is being moved vertically inside the process module.
In some implementations, a plurality of lift pins distributed in the horizontal plane may be grouped into distinct sets, with each set of lift pins being independently operable to provide different functionality. For example, the lift pins are used to tune and to replace a consumable part, such as a top ring, mid ring. The top ring, in this example, is a tunable and replaceable edge ring used in the process module of the substrate processing system and the mid ring (i.e., middle ring) is a replaceable component that is disposed between the top ring and a bottom ring. Accordingly, in one implementation, a first set of lift pins may be used to tune the top ring and a second set of lift pins may be used to replace the top ring and the mid ring. In this implementation, the first set of lift pins may be shorter than the second set of lift pins, as the first set of lift pins are used to raise the top ring to a height defined by a tuning range, which is shorter than a height where the ring transfer plane is defined. Each lift pin is connected to an actuator and the actuators of the plurality of lift pins are connected to an actuator drive that provides the power to activate the lift pins.
In an alternate implementation, the first set of lift pins are used to tune and to replace the top ring, while a second set of lift pins are used to replace a mid ring. In this alternate implementation, the height of the first set of lift pins may be same as the second set of lift pins as both set of lift pins need to raise the top ring and the mid ring from the installed position to the height of the RTP. Alternately, the height of the first set of lift pins used to move the top ring may be smaller than the height of the second set of lift pins used to move the mid ring and the difference in height may be defined by the difference in the thickness of the top ring and the mid ring.
In one example, the first set and the second set of lift pins includes 3 lift pins each, with each of the lift pins from the first set and the second set connected to a corresponding actuator. Thus, a total of 6 actuators may be present, with first 3 actuators connected to the 3 lift pins of the first set, and a second 3 actuators connected to the 3 lift pins of the second set. The lift pins and the corresponding actuators of the first set and the second set are distributed uniformly proximal to an outer edge of the lower electrode and disposed equidistant from one another, such that each actuator and the corresponding lift pin of the first set is disposed 60° apart from a neighboring lift pin, actuator from the second set. The first set of lift pin may be used to tune and remove the top ring and once the top ring is removed, the first set of lift pins are retracted and the second set of lift pins are activated to remove the mid ring.
The tuning of the top ring includes moving the top ring, each time, incrementally up to a different vertical height within the process module using the first set of lift pins so that a top surface of the top ring, after each incremental tuning, is co-planar with a top surface of the substrate received in the process module. The tuning may be done after certain number of etch operations performed in the process module or may be done based on amount of damage incurred at a top surface of the top ring.
The height to which the top ring can be moved during each incremental tuning is defined by the thickness of the top ring remaining, an amount of damage experienced at the top surface of the top ring and a predefined maximum threshold height of tuning. It should be noted herein that the maximum threshold height for tuning the top ring may be defined to be less than a height of the raised position (or replacement position) defined for the process module. The raised position is the maximum height that the lift pins 142 can be moved in order to place the top ring at the RTP so that an arm of a robot can reach into the process module, access the top ring and move it out of the process module. It should be noted herein that RTP to which the top ring is to moved is less than a height at which the top electrode of the process module is disposed. Similarly, the maximum amount of tuning that may be performed for the top ring may be driven by the thickness of the top ring remaining prior to each tuning. If the top ring has undergone tuning a predefined number of times or if the thickness of the top ring deems further tuning would damage the top ring, then it may be considered that maximum tuning has been reached, at which time the top ring has to be replaced.
The second set of lift pins is used for replacing the top ring and is, therefore, configured to lift the top ring to the raised or the replacement position, when activated. The raised or the replacement position is defined as the ring transfer plane as this position provides sufficient clearance space for an arm (i.e., an end-effector) of a robot to extend into the process module, access the top ring and transfer the top ring out of the process module without damaging any hardware component of the process module or the top ring itself.
The lift pins that are used to move the top ring are also be used to replace the mid ring 300 that is disposed below the top ring 200. In the case of replacing the mid ring, only one set of lift pins may be engaged. For instance, the second set of lift pins that was used to replace the top ring may also be used to replace the mid ring.
In one implementation, the lift pins may be used to move both the top and the mid rings (200, 300), simultaneously. In such implementation, the movement of the top ring and the mid ring may be done such that a distance of separation exists between the top ring and the mid ring so as to allow the arm of the robot to reach in and first move the top ring that is in the raised position out of the process module and then move the mid ring 300 to the raised position (i.e., RTP) so that the arm of the robot can reach back in and move the mid ring. In alternate implementations, the lift pins may be used to move the top and the mid rings separately. In yet other implementations, the first set of lift pins may be used to perform tuning and replacing of the top ring 200 and the second set of lift pins may be used to replace the mid ring 300.
The top ring may include a set of grooves (i.e., anti-walking feature) defined on the underside surface for the lift pins to allow the lift pins to engage with so that the top ring can be moved without sliding or moving out of place. The grooves may be v-shaped or alternately u-shaped. In the implementation that uses two distinct set of pins for tuning and replacing the top ring, the first set of lift pins may be slightly offset from the second set of lift pins so that each of the first and second set of lift pins may engage with the groove to provide reliable lifting. The amount of offset between the first set of lift pins and the second set of lift pins is driven by the dimensions of the grooves so that when the lift pins are activated, both the first and the second set of lift pins easily align with the v-groove. In some implementations, the grooves are formed with inclined sidewalls meeting at one end. The aligning with the groove, in such implementations, may include aligning the lift pins in each set so that the lift pins contact some part of the first sidewall or the second sidewall of the v-groove and easily slide into place within the v-groove.
In some implementations, the inclined sidewalls of the grooves meeting at one end to form a sharp tip forming a v-shaped groove. In alternate implementations, the inclined sidewalls of the v-grooves meet at a tip that is rounded (i.e., forming a u-shaped tip instead of a v-shaped tip) so that when the lift pins come in contact with the sidewalls, they slide along the inclined sidewalls and the rounded tip to end inside the u-shaped groove. To provide reliable contact with the v-shaped or u-shaped grooves on the underside surface of the top ring, the offset is defined to be less than a width of the broadest portion of the inclined walls of the v-shaped or u-shaped groove. As the first and the second set of lift pins are offset from one another, the lift pins from the first set may contact a portion of the first inclined sidewall of the anti-walk grooves and the lift pins from the second set may contact a portion of the second inclined sidewall of the anti-walk grooves, with each set of lift pins sliding into place into the v-groove. Each set of the lift pins are activated at different times and this design feature of the top ring provides reliable contact surface of the top ring for both set of the lift pins.
The lift pins 142 of the lift pin mechanism 141 are connected to a plurality of actuators 143. For example, each lift pin 142 may be connected to a distinct actuator 143. In some implementations, the actuators 143 are vacuum-sealed actuators that are outfitted with a corresponding lift pin 142. The actuators 143 are connected to one or more actuator drives (not shown) through which power is provided to drive the actuators of the lift pins. The actuator drive is, in turn, connected to a controller 122 that provides the control signal to activate the lift pins 142. The controller 122 is communicatively connected to a computer 124 through which input is provided to engage the lift pin mechanism 141.
In a disengaged mode, the lift pins 142 stay retracted inside a lift pin housing defined in the lower electrode so that they are not in contact with the consumable part (i.e., top ring 200 or mid ring 300). When a top ring 200 needs to be replaced, the actuators 143 are powered through the actuator drive. Each powered actuator 143 causes the corresponding lift pin 142 to extend out of the lift pin housing through the various channels defined in the bottom ring 234 and the mid ring 300, so as to come in contact with the top ring 200 and move the top ring 200 to a raised position. The top ring 200 is raised by the lift pin by engaging with the v-grooves of the top ring. As the process module (e.g., process module 118) is maintained in a vacuum state, when the top ring 200 is raised, the top ring 200 is raised into a vacuum space defined between the lower electrode (e.g., ESC) and the top electrode. A robot of the VTM 104 coupled to the process module 118, extends an arm with an end effector into the process module 118 and allows it to slide underneath the raised top ring 200. An input may be provided to the computer 124 to generate a signal from the controller 122 to the robot to cause the robot to extend its arm, and to the valve/gate disposed between the process module 118 and the VTM 104 so as to coordinate access to the process module 118. In some embodiments, the end effector attached to the robot is shaped like a spatula allowing the end effector to support the raised top ring. Once the end effector has slid into place to support the top ring, the actuators 143 retract the lift pins 142 into the lift pin housing, causing the top ring 200 to rest on the end effector. The arm of the robot is then retracted back into the VTM 104, bringing the top ring 200 with it. The end effector of the robot of the VTM then places the retrieved used top ring 200 in a compartment within the airlock 110 so that a robot of the EFEM 102 can retrieve the used top ring 200 from the compartment of the airlock 110 to a compartment defined in the ring storage station. A reverse order process occurs when a new top ring 200 is to be provided to the process module (e.g., 118).
The lift pin mechanism of the process module (e.g., 118) is used to properly install the top ring in its location defined in the process module (118) so that the process module (118) and the substrate processing system 100 are operational after replacement of the top ring. To properly install the top ring in its location, the top ring is pre-aligned within the ring storage station prior to moving the top ring to the process module via the EFEM and the airlock. The robots of the EFEM and the VTM maintain the pre-alignment so that when the top ring is received in the process module 118 at the raised position, the pre-aligned top ring aligns with the lift pins enabling the lift pins to engage with the v-grooves and move the top ring from the raised position to the installed position.
In some implementations, in addition to engaging with the v-grooves defined on an underside surface of the top ring, the lift pin mechanism 141 may be used to provide electrostatic clamping to clamp the top ring in position within the process module (e.g., 118) to further ensure that the top ring 200 does not move during lifting or lowering. In these implementations, the lift pin mechanism 141 may be connected to a direct current (DC) power source to allow the DC power to be provided to the lift pins 142 in order to clamp the top ring in position within the process module (e.g., 118). In alternate implementations, the lift pin mechanism may be connected to an air compressor or other compressed pressure source instead of a electrical power source to allow the lift pin mechanism to be operated pneumatically instead of electrically.
The controller 122 may include a vacuum state control (not shown) and a transfer logic (not shown) to facilitate coordinating operation of the various modules and components that are connected to the controller 122. In one implementation, when a top ring is to be replaced in the process module 118, the ring storage station is coupled to the EFEM 102. In response to detecting coupling of the ring storage station at the EFEM 102, a signal may be sent from an isolation valve (not shown) disposed between the EFEM and the ring storage station, to the controller 122. In response to the signal from the isolation valve, the controller 122 coordinates the operation of the robot of the EFEM 102, the pumping of the airlocks, the robot of the VTM 104, the isolation valve/gates disposed between the VTM 104 and the process module 118, and the lift pin mechanism 141 in the process module 118.
For example, in response to the signal from the isolation valve at the EFEM 102, the controller 122 may send a control signal to the lift pin mechanism 141 to activate the actuators 143. The activated actuators 143 power the lift pins 142 so that the lift pins extend out from the lift pin housing through the channels defined in the bottom ring and the mid ring 300 of the lower electrode and contact a bottom surface of the top ring 200. The top ring, as stated earlier, may include a set of v-grooves defined on an underside surface. In some implementations, the top ring may include a channel defined in the bottom surface of the top ring 200 running parallel to a circumference of the bottom surface. The channel may be defined in the middle of the bottom surface. The v-grooves may be distributed uniformly in the bottom surface along a radial plane and be positioned between the outer circumference of the top ring and an outer edge of the channel, and open into the channel defined in the bottom side of the top ring. These v-grooves are aligned with the lift pins so that the lift pins engage with the v-grooves.
In some implementations, a set of three lift pins are provided in the lift pin mechanism to align with a set of three v-grooves defined on the bottom surface of the top ring 200. The number of lift pins and the corresponding v-grooves are not restricted to three but can include additional lift pins/v-grooves so long as they can provide reliable kinematic support to the top ring.
The control signal executes a transfer logic to coordinate movement of the top ring from the process module 118 to a compartment in the ring storage station. For example, the transfer logic is configured to send necessary signals to operate the isolation valve or gate separating the VTM 104 from the process module 118 and to activate the robot of the VTM 104 to retrieve the top ring from the process module 118. The activated robot extends its arm with an end-effector (not shown) into the process module to retrieve the top ring that has been lifted to a raised position by the lift pin mechanism 141. In addition, the transfer logic of the controller 122 may send a vacuum state signal to a vacuum control module to begin the process of pumping the airlock 110 interfaced between the VTM 104 and the EFEM 102, to vacuum. In response to the vacuum state signal received from the transfer logic, the vacuum control module may activate a pump within the airlock 110 to allow the pump to bring the airlock 110 to a vacuum state. Once the airlock 110 has reached a vacuum state, a second signal is sent from the vacuum control module to the transfer logic. The transfer logic then sends a third signal to the robot of the VTM 104 to retrieve the used top ring retrieved from the process module and store in a compartment within the airlock 110. Upon detecting presence of the used consumable part in the airlock 110, a fourth signal may be sent by the transfer logic to pump the airlock 110 to atmospheric condition. Once the atmospheric condition has been reached in the airlock 110, a fifth signal may be sent by the controller 122 to the robot of the EFEM 102 to retrieve the used consumable part from the airlock 110 and move it to a compartment within the ring storage station. A new consumable part is then retrieved from the ring storage station and the process of moving the new consumable part to the process module 118 is carried out in a reverse order.
As the lift pin with the engaged sleeve 236 is moved up, the sleeve 236 balances and moves the mid ring 300 with it. The bottom member of the lift pin with the engaged sleeve 236 moves the mid ring 300 to a height defined by the RTP 410, as shown in
In one implementation, the top ring and the mid ring are moved together but removed separately, one at a time.
Once the top ring is moved and the arm of the robot has been withdrawn from the process chamber, the lift pin continues to be extended so that the mid ring can be moved a height “E”, as shown in
After the top ring has been moved out of the process module, the lift pin continues to move the mid ring from the installed position to the replacement position.
Once the mid ring has reached the RTP, the lift pin is partially retracted thereby allowing the top ring to mate with the mid ring at the RTP plane.
The various implementations described herein provide ways to replace the top ring and the mid ring in an efficient manner without breaking vacuum of the process module so that the process modules can be conditioned faster and returned to active processing in a short time. The geometry of the top ring with the grooves defined on the underside surface along with features of the lift pins enable reliable movement of the top ring when the top ring is being raised and lowered, as well as, when the top ring is being moved into and out of the process module during replacement. The collar defined in the lift pins allows the top member of the lift pin to pass through the mid ring to raise/lower the top ring (e.g., the edge ring). The presence of the collar also allows the mid ring to be raised and lowered, thereby allowing the mid ring to be replaced. The chamfer defined in the collar section allows a sleeve to engage with the collar so that the sleeve can engage with and move the mid ring.
The controller 122 may control activities of the precursor delivery system and deposition apparatus. The controller 122 executes computer programs including sets of instructions for controlling process timing, delivery system temperature, pressure differentials across the filters, valve positions, robots and end effectors, mixture of gases, chamber pressure, chamber temperature, wafer temperature, RF power levels, wafer chuck or pedestal position, and other parameters of a particular process. The controller 122 may also monitor the pressure differential and automatically switch vapor precursor delivery from one or more paths to one or more other paths. Other computer programs stored on memory devices associated with the controller 122 may be employed in some embodiments.
Typically there will be a user interface associated with the controller 122. The user interface may include a display 618 (e.g. a display screen and/or graphical software displays of the apparatus and/or process conditions), and user input devices 620 such as pointing devices, keyboards, touch screens, microphones, etc.
Computer programs for controlling delivery of precursor, deposition and other processes in a process sequence can be written in any conventional computer readable programming language: for example, assembly language, C, C++, Pascal, Fortran or others. Compiled object code or script is executed by the processor to perform the tasks identified in the program.
The control module (i.e., controller) parameters relate to process conditions such as, for example, filter pressure differentials, process gas composition and flow rates, temperature, pressure, plasma conditions such as RF power levels and the low frequency RF frequency, cooling gas pressure, and chamber wall temperature.
The system software may be designed or configured in many different ways. For example, various chamber component subroutines or control objects may be written to control operation of the chamber or process module components necessary to carry out the inventive deposition processes. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, heater control code, plasma control code, lift pin mechanism control code, robot position code, end effector position code and valve position control code.
A substrate positioning program may include program code for controlling chamber components that are used to load the substrate onto a pedestal or chuck and to control the spacing between the substrate and other parts of the chamber such as a gas inlet and/or target. A process gas control program may include code for controlling gas composition and flow rates and optionally for flowing gas into the chamber prior to deposition in order to stabilize the pressure in the chamber. A filter monitoring program includes code comparing the measured differential(s) to predetermined value(s) and/or code for switching paths. A pressure control program may include code for controlling the pressure in the chamber by regulating, e.g., a throttle valve in the exhaust system of the chamber. A heater control program may include code for controlling the current to heating units for heating components in the precursor delivery system, the substrate and/or other portions of the system. Alternatively, the heater control program may control delivery of a heat transfer gas such as helium to the wafer chuck. The valve position control code may include code to control access to a process module or the substrate processing system by controlling isolation valves that provide access to the process module or the cluster tool, for example. The lift pin mechanism control code may include code to activate the actuator drive to cause the actuators to move the lift pins, for example. The robot position code may include code to manipulate the position of the robot(s) including manipulation of the robot to move along a lateral, a vertical, or a radial axis, for example. The end effector position code may include code to manipulate the position of the end effector including manipulation of the robot to extend, contract, or move along a lateral, a vertical or radial axis, for example.
Examples of sensors that may be monitored during deposition include, but are not limited to, mass flow control modules, pressure sensors such as the pressure manometers 610, and thermocouples located in delivery system, the pedestal or chuck (e.g. the temperature sensors 614). Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain desired process conditions. The foregoing describes implementation of embodiments of the invention in a single or multi-chamber semiconductor processing tool.
The various embodiments described herein allow the consumable parts to be replaced in a fast and efficient manner without having to open the substrate processing system to Atmospheric conditions. As a result, the time to replace consumable parts, as well as any risk of contaminating the chamber during replacement of consumable parts is greatly reduced, thereby allowing the substrate processing system to come online faster. Further, risk of inadvertent damage to the process module, the consumable part and to other hardware components in the process module are greatly reduced.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.
Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications can be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein, but may be modified within their scope and equivalents of the claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US20/29408 | 4/22/2020 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62846579 | May 2019 | US |
