Detection method for seized traveling lift pins in wafer processing reactor systems

A reactor system with stuck lift pin detection. The system includes a reaction chamber, a susceptor for supporting wafers in an interior space of the reaction chamber, and an elevator for raising and lowering the susceptor in the interior space. Further, the system includes a lift pin supported by and extending vertically through the susceptor to travel between an up and a down position with movements of the susceptor by the elevator, and a landing pad is provided in the system for receiving a base of the lift pin when the lift pin is in the down position. Significantly, the system also includes a sensor assembly with a sensor positioned at least partially within the interior space of the reaction chamber. An output signal of the sensor is indicative of whether the lift pin is sticking or seizing during travel through the susceptor.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to methods and systems utilizing lift pins to lift wafers from susceptors in a wafer processing or reactor system, and, more particularly, to methods and apparatus for detecting seized or stuck lift pins in a semiconductor processing or reactor system.

BACKGROUND OF THE DISCLOSURE

Semiconductor processing techniques, including atomic layer deposition (ALD) and chemical vapor deposition (CVD), are often used for forming thin films of materials on substrates, such as silicon wafers. To carry out such processing, reactor systems or tools are used that have a reaction chamber in which a susceptor or substrate holder is positioned and used for holding wafers during wafer processing steps.

In some reaction system designs, including a number of ALD reactor system or apparatus, the susceptor is capped, and lift pins that extend upward through the susceptor and its cap are used to facilitate unloading of wafers by extending a distance above the upper surface of the cap when a susceptor elevator is lowered or in a down position to lift the wafer off the susceptor. The lift pins are considered to be in the “up” position at this stage of operations of the reactor system. When the elevator is raised to an up position to lift or raise the susceptor and its cap, the lift pins are configured to travel downward relative to the susceptor so that the top or heads of the lift pins are flush or below the upper surface of the cap.

Due to several factors, though, the wafer lift pins in reactor systems or apparatus can become stuck in the up position. In this undesirable operation condition, the head of the lift pin protrudes above the susceptor pocket position when it should be fully retracted below the surface. The result can be that a received or dropped wafer does not sit flat on the cap or in the cap (or susceptor) pocket, which can negatively impact wafer processing and lead to scrapped production wafers. For example, a tilted wafer caused by a stuck lift pin(s) can cause non-uniform deposition due to a non-uniform or undesired wafer temperature profile and dead volume created by the tilted wafer.

Often, the problem of seizing or sticking lift pins can go undetected until a daily monitor is run and many wafers are impacted. Existing design approaches have not been widely effective or adopted. One approach to monitoring lift pin travel is to use a series of lasers through lower reaction chamber view ports to attempt to see if the bottom of the pin is at the proper height, which can indicate that the pin is properly recessed. This is an expensive solution and occupies view ports that are more preferably used for visual inspection and maintenance access. Also, view ports or windows can become fogged by leaking precursors, e.g., from upper reaction chamber to the lower wafer transfer chamber, and this will obscure proper viewing. Another proposed design involves having electric current pass or not pass through the contacting pin bottom and pin pad, but, in reaction chambers, film (e.g., of a dielectric or the like) buildup on the pad or pin may occur that would change resistance over time and decrease the accuracy of the pin monitoring approach.

Hence, there is a demand for a methodology to accurately and cost effectively detect the occurrence of a stuck lift pin(s) to alert the user of a reactor system or one of its chambers to stop production until the issue can be identified and resolved.

SUMMARY OF THE DISCLOSURE

More specifically, the present description provides a reactor system with stuck lift pin detection. The system includes a reaction chamber, a susceptor for supporting wafers in an interior space of the reaction chamber, and an elevator for raising and lowering the susceptor in the interior space. Further, the system includes a lift pin supported by and extending vertically through the susceptor to travel between an up and a down position with movements of the susceptor by the elevator, and a landing pad is provided in the system for receiving a base of the lift pin when the lift pin is in the down position. Significantly, the system also includes a sensor assembly with a sensor positioned at least partially within the interior space of the reaction chamber. An output signal of the sensor is indicative of whether the lift pin is sticking or seizing during travel through the susceptor.

In some useful embodiments, the sensor assembly further includes a detection module displaying data based on the output signal of the sensor or processing the output signal of the sensor to detect when the lift pin is sticking or seizing during the travel through the susceptor. In such embodiments, the output signal provides a sensed temperature or pressure and wherein the processing of the output signal by the detection module includes comparing the sensed temperature or pressure with predefined temperature or pressure disturbances associated with travel of the lift pin free of sticking or seizing or includes comparing timing of the sensed temperature or pressure with reference to movements of the elevator.

In these or other implementations, the system may also include a cap covering an upper surface of the susceptor, and the sensor may include a temperature sensor positioned within a passageway provided in a body of the cap, whereby the output signal is associated with a sensed temperature of the cap. In such cases, the temperature sensor may include a thermocouple or a resistance temperature detector positioned proximate to a center axis of the cap. Additionally, the temperature sensor may include a line for carrying the output signal extending away from the thermocouple or the resistance temperature detector, and the line may include two or more coils in the interior space of the reaction chamber. In the same or other cases, the temperature sensor may include a thermocouple or a resistance temperature detector positioned a radial distance from an edge of the cap that is in the range of 40 to 60 millimeters.

In other embodiments of the system, the sensor may include a temperature sensor positioned within the landing pad, whereby the output signal is associated with a sensed temperature of the landing pad. In such embodiments, the temperature sensor may include a thermocouple or a resistance temperature detector positioned in a head of the landing pad adapted for receiving the base of the lift pin.

In other exemplary embodiments, the sensor includes a gas inlet in the landing pad, a pressure sensor disposed exterior to the reaction chamber, and a flow line fluidically coupling the landing pad to the pressure sensor, whereby the output signal is associated with a sensed pressure in the flow line. In such embodiments, the gas inlet may include a hole in a head of the landing pad. Then, the base of the lift pin covers or obstructs flow of gas through the hole when the lift pin is in the down position, and the sensor assembly may further include a gas pump coupled to the flow line operable to draw gas from the interior space of the reaction chamber through the landing pad and the flow line.

According to some aspects of the description, a method is provided for monitoring lift pin travel in a reaction chamber. The method includes, with a temperature sensor, sensing a temperature of a susceptor cap at an operational state of the reaction chamber. The method also includes comparing the temperature of the susceptor cap with a predefined range of expected temperatures for the operational state of the reaction chamber. Then, the method involves, when the comparing determines the temperature of the susceptor cap is outside the predefined range of expected temperatures, generating an alert message or updating a graphical user interface (GUI) indicating a stuck lift pin condition.

In some embodiments of this method, the operational state of the reaction chamber is associated with dropping a wafer upon an upper surface of the susceptor cap. In these or other implementations of the method, the temperature sensor includes a thermocouple or a resistance temperature detector positioned within the susceptor cap.

All of these embodiments are intended to be within the scope of the disclosure. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of certain embodiments having reference to the attached figures, the disclosure not being limited to any particular embodiment(s) discussed.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the disclosure extends beyond the specifically disclosed embodiments and/or uses of the disclosure and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the disclosure should not be limited by the particular embodiments described herein.

The illustrations presented herein are not meant to be actual views of any particular material, apparatus, structure, or device, but are merely representations that are used to describe embodiments of the disclosure.

As described in greater detail below, various details and embodiments of the disclosure may be utilized in conjunction with a reactor system with one or more reaction chambers configured for a multitude of deposition processes, including but not limited to, ALD, CVD, metalorganic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), physical vapor deposition (PVD), plasma-enhanced chemical vapor deposition (PECVD), and plasma etching. The embodiments of the disclosure may also be utilized in semiconductor processing systems configured for processing a substrate with a reactive precursor, which may also include etch processes, such as, for example, reactive ion etching (RIE), capacitively coupled plasma etching (CCP), and electron cyclotron resonance etching (ECR).

The inventors recognized the importance of sensing or detecting when a lift pin seizes or sticks preventing or delaying its travel from an up to a down position. To address this problem, reactors systems are described herein that are configured to provide relatively simple and cost effective ways to detect the occurrence of a stuck pin or pins and, in response, to alert an operator of a reactor system to address the issue. In brief, a reactor system design is taught that includes a sensor assembly that is adapted to sense or detect when a lift pin is sticking or seizing so that it remains temporarily or permanently in the up position (with its top portion or head above an upper surface of the susceptor or a susceptor cap). A detection module or routine run by a processor(s) of the sensor assembly processes sensor signals (or sensor data) to determine when a pin has stuck or seized (e.g., by identifying a temperature or pressure disturbance from normal operating parameters, by identifying when a lift pin does not mate with the pin pad, or the like) and, in some cases, responds by generating a stuck pin alert that is communicated (e.g., via a graphical user interface (GUI), via a text message, or the like) to an operator of the reactor system for action.

The sensor assembly may use a variety of sensors to sense a stuck lift pin in a reactor system. In one embodiment, the sensor is provided on the pin landing pad to sense a stuck lift pin, e.g., by detecting absence of a pin during operations when it should be received on the pad. The sensor, in this case, may take the form of capacitive sensor (e.g., one suited for a particular chamber environment such as 300 C or the like at vacuum and with a small form factor for mounting on the pin landing pad) provided on each pin landing pad. In other embodiments (illustrated in detail in the figures), the sensor assembly is configured for thermal monitoring or for pressure monitoring to detect a stuck lift pin.

An advantage of each of these techniques is they are durable and inexpensive with respect to the chamber environment. For thermal-based sensing, thermocouples are already known to be useful in the low pressure and hot environments associated with semiconductor processing. For pressure-based sensing, a small leak can be used to allow pressure detection outside the lower chamber in ambient, non-harsh environments with relatively inexpensive, durable, and low footprint components that do not impact service of the reactor system.

The thermal monitoring may involve monitoring temperatures of the landing pin or of the susceptor cap. In the landing pin embodiments, thermal monitoring is performed for each of the pin landing pads, with the detection module or algorithm operating to look for a change in temperature associated with a hot pin touching a cooler landing pad (i.e., expected temperature changes). In this implementation, a temperature sensor (e.g., a thermocouple or resistance temperature detector (RTD)) is brought into contact with the underside of the pin pad surface (e.g., where the pin rests when elevators are in down or lowered position to expose the pin for wafer handoff) from behind.

The thermal monitoring embodiment uses the concept that when the pin is on the pad the temperature sensor will be at one temperature and when the pin is off the pad the temperature sensor and pad will be at a different or second temperature. The detection module/software may use an algorithm that looks for an absolute temperature or a rapid temperature change during elevator movement so as to compare current reactor system behavior with a predefined or known set of “good” or expected behavior when the lift pins are not sticking. If a change in temperature does not occur at all or occurs at a different time relative to the other lift pins, an alert or warning can be issued for production to stop and visual troubleshooting to commence. Deposition on either the pin or pad should not substantially change behavior from this known temperature baseline. Similar monitoring algorithms can be used when the temperature sensor is placed in the susceptor or its cap.

The pressure or vacuum sensing embodiments include a sensor assembly configured to monitor pressure or pressured changes to determine when or if a lift pin comes down to touch a corresponding landing pad, which changes the gas conduction of the hole in the pad by adding resistance or blocking the hole. In some implementations, a hole is drilled through the pin pad assembly to allow a small gas flow from the lower chamber (e.g., inert gas such as nitrogen) to the process foreline or other dedicated exhaust when the pin is in the up position. When the pin and its base contact the pad, the hole is blocked or at least partially obscured and the pressure below the weep hole in the pad will drop and approach that of the exhaust. A pressured transducer can be used to identify when or if this occurs. Alternatively, a pressure switch may be used to detect flow or no-to-low flow conditions in the pad assembly and trigger a digital output/signal for each pin. The detection module may then be used to trigger a warning or alert based on, for example, a comparison of the pins to each other or to a known or predefined acceptable or expected (“good”) pressure baseline during elevator movements or operations.

FIG.1is a simplified cross-sectional view of a portion of a reaction chamber100that may be provided in a reactor system. The chamber100has a sidewall104in which a viewport106is provided for visually inspecting the interior space of the chamber100. The chamber100has a conventional layout with an elevator120that can move up and down between up and down positions (or load and unload wafer positions) as shown with arrow121. The elevator120supports and moves a susceptor130with a cap132adapted with an upper surface133for supporting a wafer (not shown) during deposition processes in the chamber100, with the elevator120and susceptor130shown in the down position inFIG.1.

To facilitate loading and unloading of wafers, a landing pad assembly140is shown that includes a stationary landing pad142. Further, a number lift pins are provided, with one landing pad assembly140per lift pin (e.g., three lift pins paired each paired with a landing pad assembly140). As shown, a lift pin150is provided that is paired with landing pad assembly140. The lift pin150includes an elongated body or shaft152that extends through a passageway in the susceptor130and cap132, and a head154is provided at a top end or portion of the body152. The head154extends above the upper surface133of the cap132when the susceptor130is in the down position due to movement121of the elevator.

To this end, the lift pin150includes a base156at a bottom end or portion of the body152that mates with the landing pad142to halt or limit downward travel of the pin150with elevator120. A spring158extends over an exterior surface of the body152and contacts a lower portion of the susceptor130(or another component attached to the susceptor130), and the spring158is compressed when the elevator120is moved121into the down position and is released to move to its at-rest configuration when the elevator120moves121to the up or raised position. This causes the pin150to be lowered with the head154flush or below the surface133of the cap132, when deposition or other processes may occur in chamber100. When a pin150sticks or seizes, however, the spring force may not be adequate cause the pin150to properly move downward or such movement may be delayed.

FIG.2is an enlarged view of a portion of the reaction chamber100ofFIG.1showing the lift pin150and landing pad assembly140in greater detail. As shown, a pin guide/bushing260is provided that is mated with a lower surface of the susceptor130that acts to guide the vertical travel of the body152of the lift pin150. The pin guide/bushing260also acts as a mating surface for the upper end of the spring158to limit its upward travel and assist in its compression with downward movement of the elevator and susceptor130. InFIG.2, the susceptor130is in the up or raised position, and the spring158has been released to its at-rest (or nearly so) position to move the pin body152downward relative to the susceptor130and cap132such that the head154of the lift pin150is recessed from or flush with the upper surface133of the cap132, as desirable for wafer placement/support on the cap132during processing. A gap270with a height, hgap, (e.g., 15 to 35 millimeters or more) is created between the landing pad142and the base156of the lift pin150.

As can be seen fromFIGS.1and2, chamber and lift pin designs conventionally were selected such that the susceptor130moves down for wafer load, which pushes pins150upward as bottom or base156of the pin150contacts the landing pad142(which may be mounted to a bottom plate of the chamber100). Susceptor130is moved up with movement121of the elevator120inside the chamber100for processing of a wafer received on the surface133of the cap132. Lift pins150travel up with the susceptor130, and no longer contact the landing pad142. Springs158force the pin head154to retract into the susceptor130or its cap132. With a wafer in place, it can be difficult to track the pin head154location inside the chamber100from the available side viewports such as viewport106in sidewall104of the chamber100.

Now, turning first to the thermal monitoring approach to detecting stuck lift pins,FIG.3illustrates a schematic diagram of a portion of a reactor system300configured according to the present description to utilize temperature sensors positioned in the landing pads to detect stuck or seized lift pins. The inventors recognized that lift pins will have a higher temperature when they are in the process position (with the elevator and susceptor in the raised or up position) compared to landing pads, which will be at steady state lower temperature(s). With this in mind, a temperature sensor could be mounted in-situ on each pin landing pad to monitor temperature variations when pins rest on pads to detect when a pin is stuck, e.g., the temperature of one the pads does not increase as expected or in a similar manner to the other pads.

As shown inFIG.3, the reactor system300includes a reaction or vacuum chamber310with an interior space315in which wafers may be processed. The chamber310may generally be configured similar to the chamber100ofFIG.1, with landing or pin pads318provided to mate with a like number of lift pins supported upon a susceptor (as shown inFIG.4and understood fromFIGS.1and2). A sensor assembly320is included in the reactor system300and is adapted for detecting when one of the lift pins sticks through thermal monitoring within the interior space315of the chamber310.

The sensor assembly320includes temperature sensors322,324, and326(shown as thermocouples but may take other forms such as RTDs or the like) in the space315. More particularly, a thermocouple322,324,326is mounted into each of the pin or landing pads318in the space315(with three being shown in this non-limiting example). Communication lines329extend outward from each thermocouple322,324,326out of the chamber310through a TC feedthrough328.

The sensor assembly320includes a processor(s)330that executes software, code, or instructions (that may be in memory340) to provide the functions of a detection module332, which include processing signals from the thermocouples322,324,326. Further, the sensor assembly320includes memory or data storage340that is managed by the processor330to facilitate operations of the detection module332. To this end, the memory340may store a set of predefined baseline parameters or setpoints344for the operations of the system300. These may include expected temperatures and/or temperature increases for the pads318when lift pins are resting upon or contacting the pads318. The parameters344may also include timing of elevator movements to allow the detection module332to match elevator movements (and corresponding susceptor positions) with measured temperatures of the pads318.

For example, the module332may determine that an expected temperature disturbance (a rise in pad temperature) is not seen or is delayed for one (or more) of the pads318and, in response, may generate an alert or warning of a potentially stuck pin. This alert may be communicated to an operator or use of system300such as via a graphical user interface (GUI)350on a monitor/display device. In some cases, the outputs (sensed pad temperatures) from the thermocouples322,324, and326are displayed on the GUI350to provide real-time (or near real-time) monitoring of pad temperatures and/or temperature variations between the pads318(e.g., when pins are expected via elevator movements to be resting on the pads318). For example, testing has indicated there may be delay of temperature disturbance (rising) of 3 to 4 seconds in the case of a pin that is experiencing sticking, and this delay in temperature disturbance may be used by the detection module as an indicator of a stuck pin (e.g., a delay of greater than “X” produces an alert or a delay in the range of “Y to Z” produces such an alert).

FIG.4illustrates a simplified cross-sectional view of a portion of a reaction chamber400in which the thermal monitoring provided by system300may be implemented. As shown, the chamber400includes in interior space405in which an elevator420is provided to support and selectively raise and lower a susceptor430. A number (e.g., three) of lift pins are supported by the susceptor430and move with it during operations of the elevator420. The susceptor430is shown to be in the up or raised position. In this operation state of the chamber400, a lift pin450is raised, too, such that its bottom portion or base456is spaced apart from a corresponding pin or landing pad442.

The landing pad442(as well as other pads in the chamber400) has been modified to include a temperature sensor (not visible inFIG.4but shown inFIGS.3,5, and6) such as a thermocouple or RTD, and a communication or connection wire/line443is shown to communicatively link the temperature sensor in the landing pad442with other components (e.g., a processor330and/or TC feedthrough) of a sensor assembly (e.g., assembly320ofFIG.3) to provide its output data/signals (e.g., sensed temperatures of pad442) for display and/or further processing.

FIG.5is an enlarged partial view of the reaction chamber ofFIG.4showing, with a sectional view, more details of a pin or landing pad design supporting thermal monitoring to detect stuck lift pins, and view550is a further enlargement showing modification of the landing pad442in more detail. As shown, the lift pin450is in a down or pin-rest position (e.g., in response to lowering of the susceptor by the elevator), with its base456resting on or in abutting contact with the upper surface of the pin or landing pad442. In this position, heat from the pin450is transferred via conduction to the pad442causing its temperature to rise.

The pin pad442is modified, when compared to a conventional pad, to have an increased thickness (or head thickness), tpad, to allow the thermocouple545to be mounted within the pad442. For example, the thickness may be increased by 2 to 4 mm or more to allow a thermocouple545to be received within a recessed portion or passageway in the pad442. This places the thermocouple545in contact with the material of the pad442and near its upper surface that abuts/receives the base456of the pin450(e.g., as close as practical such as within 0.5 to 2 mm or the like) to facilitate temperature monitoring. Typically, as shown, the thermocouple545is positioned at or proximate to the center of the pad442for more accurate readings.

In some applications of the thermal monitoring concept, it may be desirable to monitor other components in the reaction chamber to detect seized or stuck pins. In one useful example, the inventors determined that it may be desirable to monitor the temperature of the susceptor cap instead of pin or landing pads to detect, based on temperature variances, the presence of a stuck or seized lift pin.

During wafer processing, there is an expected temperature disturbance or change for a susceptor cap when a cold wafer is dropped or placed on the upper surface of the susceptor (i.e., when the susceptor is raised by the elevator causing the heads of the lift pins under spring forces to become recessed or flush with the cap surface when operating normally or without sticking). This baseline range or parameter (e.g., a temperature drop of 2 to 8° C. or the like with some testing showing 2.5 to 3° C. in some chamber designs while others see 5 to 6° C. drops) can be used to detect stuck pins as the temperature drop is not seen or experienced with a delay. A temperature sensor, such as a thermocouple, may be provided in the susceptor cap to monitor its temperature.

The system300ofFIG.3would be modified to implement this alternative embodiment with the three thermocouples322,324,326being replaced (typically) with a single thermocouple that is mounted within the susceptor cap instead of within landing pads (or the heads of such pads). The baseline parameters344would be modified to provided expected temperature variances for the susceptor cap and/or timing of such variances with respect to elevator movements, and the detection module322would process temperatures sensed for the susceptor cap to identify potential stuck or seized pin conditions (e.g., a smaller temperature drop (e.g., 2 to 3° C. difference in the sensed temperature drop) or a delayed temperature disturbance), with alerts/warnings or monitored data communicated to users such as via GUI350.

FIG.6is a side sectional view of a portion of a reaction chamber600with a susceptor cap632adapted for thermal monitoring according to another embodiment of the present description.FIG.7is an enlarged view of a portion of the susceptor cap630ofFIG.6prior to insertion of a thermocouple670(or other temperature sensor) illustrating additional features of the modified cap. As shown, the chamber600includes an interior space605in which an elevator620is provided that supports and raises and lowers a susceptor630. The cap632is positioned over the susceptor630to move with it and with an upper surface633facing upward in the space605. During wafer processing operations, cold wafers are dropped upon the surface prior to deposition and other processes, and the susceptor cap632is configured to provide thermal monitoring useful for detecting stuck lift pins (not shown but understood fromFIGS.1-5).

The sensor assembly in this case would include the temperature sensor670that may take the form of a thermocouple (e.g., a stainless steel (SS)-sheathed TC). Its head or sensor element674is positioned at the end of a passageway638(e.g., a drilled hole) in the body of the susceptor cap632such that is located at or near the center axis, AxisCenter, of the cap632. As shown inFIG.7, the passageway638extends from an inlet782to an internally-located end wall784, against which a sensor element (or TC)674would be positioned upon assembly. The sensor element or end (or TC or RTD) may be positioned at a sensing location as near to the surface633of the cap632as practical (such as 0.5 to 2 mm from the surface633of the cap) to provide more accurate temperature sensing.

To facilitate maintenance and installation of the temperature sensor670, a number of slots/windows788(e.g., machined slots or the like) are provided on the bottom surface of the susceptor cap632to provide access to the passageway638to allow an assembler to push or guide the temperature sensor670along the passageway638. A threaded hole789is provided in the lower surface of the cap632to allow a set screw to be inserted and secure the sensor670in place in the passageway638. Since the elevator620will go up and down repeatedly (e.g., 40 mm of vertical travel may be expected in some cases), a conventional thermocouple may be damaged by stretching and fatigue. Hence, the sensor cord678is shown to be configured with a pig tail arrangement with two, three, or more coils to provide a spring-like action that provides relief and accommodates the movement of the elevator620and cap632on susceptor630and avoids wear or damage of the sensor670.

In some embodiments, a less central sensing position may be chosen to reduce the overall length of the portion of the sensor (or cord) within the body of the cap (such as from about 6 inches down to about 3 inches or less). For example,FIG.8is side sectional view of the reaction chamber600ofFIG.6illustrating an additional susceptor cap configuration for facilitating thermal monitoring to detect stuck lift pins, andFIG.9is an enlarged view of a portion of the susceptor cap832ofFIG.8prior to insertion of a thermocouple674illustrating additional features of the modified cap832.

As shown, the design is similar to that ofFIG.6with several differences. The passageway838in the body of the cap832used to receive and position the thermocouple674is much shorter, with a radial distance (or distance from an outer edge of the cap832), d, that may be in the range of 40 to 60 mm rather than one that is the entire radius of the cap832(or some amount less such as 10 to 20 mm less than the cap radius) as shown inFIG.6. The thermocouple674would again be located proximate to the surface833of the cap832within the passageway838, and it is believed that temperature measurements will be comparable to those achieved with the embodiment ofFIGS.6and7.

As seen inFIG.9, the shortened bore/passageway838exits via an outlet882the side of the cap832rather than via a bottom surface of the cap832. The cutout slots or windows shown inFIG.7are also eliminated as it is less likely that the sensor cord will become bent or deformed in the shorter run passageway838. The passageway838ends at an interior end wall884, against which the thermocouple/sensor element674would be positioned in abutting contact in its final sensing position upon assembly as shown inFIG.8. A threaded hole889in the bottom surface of the body of the cap832is provided near this end wall884to allow a set screw (not shown) to be inserted to secure the sensor670in place within the cap832. The bore/passageway838may have two diameters for receiving the sensor element/TC674having a smaller outer diameter near the end wall884and the sheathed cord having a larger outer diameter near the passageway inlet882.

Turning now to use of pressure monitoring to detect stuck lift pins,FIG.10illustrates a schematic diagram of a portion of a reactor system1000configured according to the present description to utilize pressure sensors with inlets provided or positioned in the landing pads in the reaction chamber to detect stuck or seized lift pins. The inventors recognized that by providing a flow of gas through pin or landing pads within a reaction chamber changes in pressure can be monitored to detect a stuck lift pin. Specifically, continuous vacuum pumping from the base of the pin pads through a central hole can be provided. Then, absolute pressure is sensed when the pins are lifted up and exhaust pressure is sensed when pin bases contact the pin pads and cover or obstruct the hole or pressure sensor inlets. A pressure drop can be monitored by individual sensors (e.g., pressure transducers, pressure sensors, or the like) for each pin when pins rest on the pin pad, and, based on this monitored pressures, alerts or warnings can be generated and communicated to operators of the system1000.

As shown inFIG.10, the reactor system1000includes a reaction or vacuum chamber1010with an interior space1015in which wafers may be processed. The chamber1010may generally be configured similar to the chamber100ofFIG.1, with landing or pin pads1022provided to mate with a like number of lift pins1018supported upon a susceptor (as shown inFIG.4and understood fromFIGS.1and2). A sensor assembly1020is included in the reactor system1000and is adapted for detecting when one of the lift pins1018sticks through pressure monitoring of gas flow through inlets provided in each of the pads1022within the interior space1015of the chamber1010.

The sensor assembly1020includes pressure sensors1028fluidically linked via separate gas flow lines1026. Gas flow lines1026are each coupled to one of the inlets/holes1024in one of the pads1022and run from the interior space1015of the chamber1010to an exterior space or location outside the chamber1010. For example, each pressure sensor1028may take the form of a pressure transducer, a pressure switch, or other pressure sensing device in fluid communication with the lines1026, and a vacuum pump1029may be provided to provide continuous vacuum pumping from the base of each pin pad1022. In this way, the pressure sensors1028will generate a signal or output indicative of a pressure at or near absolute when the pins1018are lifted up and at or near exhaust pressure when the bases of the pins1018are on or contacting the pin pads1022.

The sensor assembly1020includes a processor(s)1030that executes software, code, or instructions (that may be in memory1034) to provide the functions of a detection module1032, which include processing signals from the pressure sensors1028to detect stuck or seized pins. Further, the sensor assembly1020includes memory or data storage1034that is managed by the processor1030to facilitate operations of the detection module1032. To this end, the memory1034may store a set of predefined baseline parameters or setpoints1036for the operations of the system1000. These may include expected timing of and, in some cases, magnitudes of pressure drops in lines1026(each associated with one pad1022and one lift pin1018).

For example, testing may be performed to determine experienced pressure drops then an elevator in the chamber1010moves so as to position the pins1018against the pads1022, and these values may be stored as parameters/set points1036for use in identifying a stuck pin1018(e.g., pressure drop not seen when expected or at a delayed time) are resting upon or contacting the pads1022(and covering or obstructing inlets1024to the lines1026(that may take the form of a weep hole in the pads1022). The parameters344may also include timing of elevator movements to allow the detection module332to match elevator movements (and corresponding susceptor positions) with measured temperatures of the pads318.

The module1032may cause pressures that are sensed by the sensors1028to be displayed such as on a GUI1040on a user's monitoring device. In other cases, the module1032may process the signals from the sensors1028along with the baseline parameters/set points1036to determine that an expected pressure variance (a rise or drop in pressures in lines1026) is not seen or is delayed for one (or more) of the pads1022and, in response, may generate an alert or warning of a potentially stuck pin1018. This alert may be communicated to an operator or use of system1000such as via the GUI1040on a monitor/display device. In some cases, the outputs (sensed pressures) from the thermocouples322,324, and326are displayed, too, on the GUI1040to provide real-time (or near real-time) monitoring of sensed pressures and/or pressure variations between the pads1022(or lines1026) (e.g., sensed pressures when pins1018are expected via elevator movements to be resting on the pads1022).

FIG.11is a side sectional view of a pin pad assembly1140configured according to the present description, such as for use as a pad1022in the sensor assembly1020ofFIG.10, along with a lift pin150in the down position. To achieve pressure monitoring, the lift pin150does not require modification, and its components may be those described with reference toFIG.2including body152and base156(with a lower planar surface) at a lower end or portion of the body152.

For pressure monitoring, a new pin or landing pad assembly1140is provided for each lift pin150. As shown, the assembly1140includes a pin pad1142with an elongated body1144and a head1143extending from an upper end of the body1144to receive the base156of the pin150during operations of a reactor system. The pin pad1142is configured to provide a flow path for gas from the reaction chamber (e.g., interior space1015of chamber1010inFIG.10) to a gas flow line1160, which will extend outside the chamber. To this end, the head1143includes a weep or thru hole1145that acts as an inlet for gas to flow to a pressure sensor and extends from an upper surface of the head1143through the body1144.

The landing pad1142is supported upon a base1146(which is, in turn, supported upon a lower component of the reaction chamber). The base1146includes a passageway1147defining a gas flow path through the base1146, and, when the landing pad1142is connected with the base1146, the inlet or thru hole1145is fluidically coupled with the passageway1147so that gas can flow through the assembly1140. A coupling or seal member1150(e.g., a C-seal or the like) is provided, as shown, to couple the gas flow line1160to the base1146such that the passageway1147is coupled with the tube/line1160(or its inlet).

As discussed with reference toFIG.10, a pump can be coupled to line1160to draw gas from the space about the assembly1140through the inlet1145and passageway1147, and pressure in the line1160can be monitored to determine if the pin150is sticking (not properly moving up and down through a susceptor). Gas flow is blocked or at least obstructed when the pin150is in the down position (shown inFIG.11) with the pin base156abutting the head1143of the landing or pin pad1142(e.g., with the pin150covering or obstructing the weep or thru hole/inlet1145). When the pin150is later lifted (by operations of the elevator moving the susceptor), flow through the inlet1145is again unobstructed.

FIG.12is a top perspective view of a portion of a reactor system1200showing an interior space1215of a reaction chamber1210including three of the pin pad assemblies ofFIG.11each paired with a lift pin. As a specific example, pin pad assembly1140is shown to be paired with and receiving lift pin150(which is shown in the down position). The pin pad assembly1140is mounted to a lower wall1212of the chamber1210and is arranged to receive the lift pin150during its vertical travel (e.g., through and with a susceptor (not shown inFIG.12but understood fromFIGS.1and4) during elevator movements).

The interior space1215of the chamber1210is further defined by sidewall1214, and each pad assembly1140is provided with individual and separate gas line routing to sense pressures of gases flowing through each assembly1140during operations of the system1200. As shown, the gas flow line1160is coupled to the landing pad assembly1140and extends along the upper surface of the bottom wall1212to the sidewall1214. At this point, it passes through the sidewall1214and is coupled to an exterior section1261. A pressure sensor1266is in fluid communication with the exterior section1261of the flow line1160, and it operates to sense pressures in the line, which will vary depending upon the location of the lift pin150relative to the pad of assembly1140(e.g., pad1142inFIG.11). In this manner, pressures at each pad assembly1140(with three shown to correspond with three lift pins) can be sensed and compared with each other or with expected baselines to determine whether one or more of the lift pins150may be sticking or seizing (e.g., causing a change in the amount or timing of a pressure variance as determined by a detection module to be indicative of a stuck pin150).

Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure.

Furthermore, the described features, advantages, and characteristics of the disclosure may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the subject matter of the present application may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the disclosure. Further, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the subject matter of the present disclosure. No claim element is intended to invoke 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.”

The scope of the disclosure is to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” It is to be understood that unless specifically stated otherwise, references to “a,” “an,” and/or “the” may include one or more than one and that reference to an item in the singular may also include the item in the plural. Further, the term “plurality” can be defined as “at least two.” As used herein, the phrase “at least one of”, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. Moreover, where a phrase similar to “at least one of A, B, and C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A, B, and C. In some cases, “at least one of item A, item B, and item C” may mean, for example, without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

Although exemplary embodiments of the present disclosure are set forth herein, it should be appreciated that the disclosure is not so limited. For example, although reactor systems are described in connection with various specific configurations, the disclosure is not necessarily limited to these examples. Various modifications, variations, and enhancements of the system and method set forth herein may be made without departing from the spirit and scope of the present disclosure.

The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems, components, and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.