Mobile sensor device for semiconductor manufacturing equipment

Abstract

Systems and techniques are disclosed for obtaining various types of sensor information regarding operational aspects of semiconductor processing tools. Such systems and techniques may involve instrumented wafers that include one or more different types of sensors, including, for example, pressure sensors, oxygen (or other gas) sensors, humidity sensors, upward and / or outward-facing imaging sensors, or optical sensors, microphone sensors, etc.

Description

[Technical Field]

[0001] Related Applications A PCT application form is being filed contemporaneously herewith as part of this application. Each application to which this application claims benefit or priority, as identified in the contemporaneously filed PCT application form, is incorporated herein by reference in its entirety and for all purposes. [Background technology]

[0002] At various times, semiconductor equipment may need to be calibrated or inspected to optimize processing conditions and / or check one or more aspects of the equipment's condition. In some cases, semiconductor equipment manufacturers and operators have used wafers equipped with accelerometers and downward-facing cameras to assist in wafer movement characterization and wafer centering or calibration operations. Such wafers are described, for example, in Patent Publication No. WO2021022291, entitled "INTEGRATED ADAPTIVE POSITIONING SYSTEMS AND ROUTINES FOR AUTOMATED WAFER-HANDLING ROBOT TEACH AND HEALTH CHECK," the contents of which are incorporated herein by reference in their entirety. Summary of the Invention

[0003] The details of one or more implementations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. The following non-limiting implementations are considered part of this disclosure, and other implementations will become apparent from the entirety of this disclosure and the accompanying drawings.

[0004] In some implementations, a device for evaluating characteristics of a semiconductor processing tool or component may be provided. Such a device may include a base structure sized to be insertable through an opening of the semiconductor processing tool sized to receive a wafer for processing and to be transportable by an object transport apparatus of the semiconductor processing tool between at least two locations in the semiconductor processing tool. The base structure may have a first side configured to contact and be supported by a portion of the object transport apparatus and a second side facing in a direction opposite the first side. The device may further include one or more optical sensors, each oriented to have an upward field of view when the base structure is oriented with the first side facing downward, a controller communicatively connected to each of the one or more optical sensors, and a power source configured to provide power to at least the controller.

[0005] In some implementations, at least one of the one or more optical sensors may be an imaging sensor.

[0006] In some implementations, at least one of the one or more optical sensors may be coupled to a corresponding one or more lenses that provide the optical sensor with a field of view of at least 30 degrees.

[0007] In some implementations, the device may have two or more optical sensors, which may be distributed across the device to have overlapping fields of view with respect to a focal plane parallel to the second side and located a first distance from the second side.

[0008] In some such implementations, the first distance may be between 2 mm and 100 mm.

[0009] In some implementations, the area resulting from the intersection of the focal plane and the field of view of the optical sensor is:

number

[0010] In some implementations, there may be multiple optical sensors, and at least two of the optical sensors may be located at different distances from a center point of the base structure.

[0011] In some implementations, the device may further include a first support structure rotatably coupled to the base structure. The device may also include a first rotational drive configured to cause the first support structure to rotate about a first axis of rotation and relative to the base structure in response to receiving one or more first control signals. At least one of the one or more optical sensors may be supported directly or indirectly by the first support structure and may be located at a distance offset from the first axis of rotation in a direction perpendicular to the first axis of rotation.

[0012] In some implementations, there may be multiple optical sensors supported directly or indirectly by the first support structure, and at least two of the optical sensors supported by the first support structure may be located at different distances from the first axis of rotation.

[0013] In some implementations, the first axis of rotation can be nominally centered on the base structure.

[0014] In some implementations, the first axis of rotation can be offset from the center of the base structure.

[0015] In some implementations, the device may further include a second support structure rotatably coupled to the first support structure. The device may also include a second rotational drive configured to cause the second support structure to rotate about a second axis of rotation and relative to the first support structure in response to receiving one or more second control signals. The second support structure may be supported by the first support structure, at least one of the one or more optical sensors may be supported by the second support structure, and the second axis of rotation may be radially offset from the first axis of rotation.

[0016] In some implementations, the base structure may have a maximum dimension that is less than or equal to 50% of the nominal wafer diameter of wafers that the semiconductor processing tool is configured to process.

[0017] In some implementations, the base structure may have a maximum dimension that is 50% or less of 300 mm, and at least one of the one or more optical sensors may be disposed at a location on the base structure that is offset from a central axis of the base structure that is perpendicular to the second side.

[0018] In some implementations, there may be multiple optical sensors, and one of the optical sensors may be located proximate to the central axis of the base structure.

[0019] In some implementations, the device may further include a first optical projection unit configured to project a first illumination pattern along a first axis. In such implementations, the first axis may be at an oblique angle to the second side, the first axis may intersect a reference plane that is parallel to and offset a first distance from the second side, the first side may be farther from the reference plane than the second side, and the one or more optical sensors may be arranged such that at least some locations where the reference plane and the first illumination pattern may intersect are within an aggregate field of view of the one or more optical sensors.

[0020] In some such implementations, the first illumination pattern may intersect the reference surface along a first line.

[0021] In some implementations, the device may further include a second optical projection unit, which may be configured to project a second illumination pattern along a second reference plane that is perpendicular to the second side and parallel to a first line along which the first illumination pattern intersects the reference plane, and the second illumination pattern may intersect the reference plane along a second line that is parallel to the first line.

[0022] In some implementations, the first illumination pattern may intersect the reference surface at multiple discrete locations distributed across the reference surface.

[0023] In some implementations, a device for evaluating characteristics of a semiconductor processing tool or component may be provided. The device may include a base structure sized to be insertable through an opening of the semiconductor processing tool sized to receive a wafer for processing and to be transportable by an object transport apparatus of the semiconductor processing tool between at least two locations in the semiconductor processing tool, the base structure having a first side configured to contact and be supported by a portion of the object transport apparatus and a second side facing in a direction opposite the first side. The device may also include one or more optical sensors, each oriented such that the optical sensor has a field of view facing outward relative to a central axis of the base structure. The device may also include a controller communicatively connected to each of the one or more optical sensors and a power source configured to provide power to at least the controller.

[0024] In some implementations, there may be multiple optical sensors, and the optical sensors may be located proximate to the outer edge of the base structure.

[0025] In some implementations, the optical sensors may be arranged in a circular array.

[0026] In some implementations, the fields of view of the optical sensors may overlap circumferentially at a radial distance from the central axis of the base structure, and the radial distance may be equal to the distance from the center of the pedestal of the semiconductor processing tool and the inner wall surface of the semiconductor processing chamber of the semiconductor processing tool.

[0027] In some implementations, the device may further include a support structure rotatably coupled to the base structure, a rotational drive configured to cause the support structure to rotate about a rotational axis in response to receiving one or more control signals, and at least one of the one or more optical sensors may be supported on the support structure.

[0028] In some implementations, the one or more optical sensors may be imaging sensors.

[0029] In some implementations, a device for evaluating characteristics of a semiconductor processing tool or component may be provided. The device may include a base structure sized to be insertable through a door of the semiconductor processing tool and transportable by an object transport apparatus of the semiconductor processing tool between at least two locations in the semiconductor processing tool, the base structure having a first side configured to contact and be supported by a portion of the object transport apparatus and a second side facing in a direction opposite the first side. The device may also include one or more first ambient air sensors supported by the base structure, each first ambient air sensor configured to measure the partial pressure of a first component of a target gas, the concentration of the first component in the target gas, the flow rate of the target gas, or any combination of two or more thereof, where the first component of the target gas is not water. The device may also include a first controller. The first controller may be communicatively connected to each of the one or more first ambient air sensors and may be supported by the base structure. The device may also include a power source configured to provide power to at least the first controller.

[0030] In some implementations, the one or more first ambient atmosphere sensors may include at least one first ambient atmosphere sensor configured to measure a partial pressure of a first component in the target gas.

[0031] In some implementations, the one or more first ambient air sensors may include at least one first ambient air sensor configured to measure a concentration of a first constituent in the target gas.

[0032] In some implementations, the one or more first ambient air sensors may include at least one first ambient air sensor configured to measure the partial pressure of a first component and also to measure the partial pressure of a second component in the target gas that is different from the first component.

[0033] In some implementations, the first component can be oxygen and the second component can be water.

[0034] In some implementations, the first component can be oxygen.

[0035] In some implementations, a system including one of the devices described above may be provided. Such a system may include a semiconductor processing tool having one or more wafer-handling robots and a semiconductor processing chamber. The system may also include a second controller communicatively coupled to the one or more wafer-handling robots. The base structure may further support a first wireless communication interface, and the second controller may be communicatively coupled to the second wireless communication interface. The second controller may be configured to communicate with the first controller via a wireless communication link using the first and second wireless communication interfaces. The second controller may be configured to cause the one or more wafer-handling robots to place the base structure in the semiconductor processing chamber and to send one or more commands to the first controller to cause the first controller to obtain sensor readings from one or more first ambient air sensors while the base structure is in the semiconductor processing chamber.

[0036] In some implementations, the second controller can be further configured to cause a door of the semiconductor processing chamber to be sealed while the base structure is within the semiconductor processing chamber.

[0037] In some implementations, the second controller may be further configured to control one or more valves to cause the flow of gas to the semiconductor processing chamber through the one or more valves to be turned off at least while the sensor readings are being obtained.

[0038] In some implementations, the second controller may be further configured to control one or more vacuum pumps or one or more vacuum valves to cause the flow of gas from the semiconductor processing chamber to stop at least while the sensor readings are being obtained.

[0039] In some implementations, there may be multiple first ambient air sensors at spaced locations on the base structure, and the first controller or the second controller may be configured to identify a local peak measurement value of the concentration or partial pressure of a first component of the target gas in the sensor readings, and the first controller or the second controller may be configured to determine which of the first ambient air sensors is associated with the local peak measurement value and determine a possible leak location in the semiconductor processing chamber based on the location of the first ambient air sensor associated with the local peak measurement value relative to the semiconductor processing chamber.

[0040] In some implementations, the one or more first ambient atmosphere sensors may include at least one sensor configured to measure a flow rate of a target gas.

[0041] In some implementations, the at least one sensor configured to measure the flow velocity of the target gas may be an anemometer.

[0042] In some implementations, the at least one sensor configured to measure the flow rate of the target gas may be a hot wire anemometer.

[0043] In some implementations, the at least one sensor configured to measure a flow rate of the target gas can be a plurality of sensors configured to measure a flow rate of the target gas.

[0044] In some implementations, the base structure may be circular and may have a diameter sized to match the diameter of the wafers that the semiconductor processing tool is configured to process, and two or more of the sensors configured to measure the flow rate of the target gas may be positioned at locations proximate to the outer edge of the base structure.

[0045] In some such implementations, two or more sensors configured to measure the flow rate of the target gas may be located at uniformly spaced locations along the outer edge of the base structure.

[0046] In some implementations, there may be at least first, second, and third sensors configured to measure the flow rate of the target gas, and the first, second, and third sensors configured to measure the flow rate of the target gas may be spaced apart at intervals of 120 degrees.

[0047] In some implementations, there may be at least first, second, third, and fourth sensors configured to measure the flow rate of the target gas, and the first, second, third, and fourth sensors configured to measure the flow rate of the target gas may be spaced apart at 90° intervals.

[0048] In some implementations, there may be one or more second ambient atmosphere sensors, each configured to measure the partial pressure of a first component of the target gas, the concentration of the first component in the target gas, or both.

[0049] In some implementations, the first component can be oxygen.

[0050] In some implementations, a system including the device described above may be provided. The system may further include a semiconductor processing tool having an equipment front-end module (EFEM) and one or more wafer-handling robots located within the EFEM. The system may further include a second controller communicatively coupled to the one or more wafer-handling robots. The base structure may further support a first wireless communication interface, and the second controller may be communicatively coupled to the second wireless communication interface. The second controller may be configured to communicate with the first controller via a wireless communication link using the first wireless communication interface and the second wireless communication interface. The second controller may be configured to cause the one or more wafer-handling robots to move the base structure between a plurality of measurement locations and to send one or more commands to the first controller to cause the first controller to obtain sensor readings from one or more first ambient air sensors associated with each measurement location and store them in one or more memory devices.

[0051] In some implementations, the semiconductor processing tool may further include a wafer buffer station located within or connected to the EFEM, the wafer buffer station having a plurality of wafer storage locations, and the plurality of measurement locations may include one or more measurement locations that coincide with one or more corresponding wafer storage locations.

[0052] In some implementations, the multiple measurement locations may include one or more measurement locations within the interior of the EFEM.

[0053] In some implementations, the semiconductor processing tool may further include a load port configured to receive a front-opening unified pod (FOUP), and the multiple measurement locations may include one or more measurement locations that correspond to locations within the FOUP when the FOUP is loaded onto the load port.

[0054] In some implementations, a device for evaluating characteristics of a semiconductor processing tool or component may be provided. The device may include a base structure sized to be insertable through a door of the semiconductor processing tool and transportable by an object transport apparatus of the semiconductor processing tool between at least two locations in the semiconductor processing tool, the base structure having a first side configured to contact and be supported by a portion of the object transport apparatus and a second side facing in a direction opposite the first side. The device may further include one or more sound sensors supported by the base structure, a controller communicatively connected to each of the one or more microphone sensors and supported by the base structure, and a power source configured to provide power to at least the controller.

[0055] In some implementations, the one or more sound sensors may be multiple microphone sensors disposed at different locations on the base structure.

[0056] In some implementations, the microphone sensors in the plurality of microphone sensors may be arranged in a circular array on the base structure.

[0057] In some implementations, the one or more microphone sensors may be omnidirectional microphone sensors.

[0058] In some implementations, the one or more microphone sensors may be directional microphone sensors.

[0059] In some implementations, the device may further include a support structure rotatably coupled to the base structure, a rotational drive configured to cause the support structure to rotate about a rotational axis in response to receiving one or more control signals, and at least one of the one or more microphone sensors is a directional microphone sensor and is supported by the support structure.

[0060] In some implementations, a device for evaluating characteristics of a semiconductor processing tool or component may be provided. The device may include a base structure sized to be insertable through a door of the semiconductor processing tool and transportable by an object transport apparatus of the semiconductor processing tool between at least two locations in the semiconductor processing tool, the base structure having a first side configured to contact and be supported by a portion of the object transport apparatus and a second side facing in a direction opposite the first side. The device may also include a plurality of different types of sensors supported by the base structure, the types of sensors including sensors configured to detect acoustic signals, sensors configured to detect optical phenomena, sensors configured to measure gas flow rates, and / or sensors configured to detect gas concentrations. The device may also include a power source configured to provide power to at least the controller.

[0061] In some implementations, the device may further include an inductive charging coil coupled to the power source.

[0062] Various implementations disclosed herein are illustrated by way of example, and not limitation, in the figures of the accompanying drawings in which like reference numerals refer to like elements and in which: [Brief explanation of the drawings]

[0063] [Figure 1] FIG. 1 is a schematic diagram of a sensor-equipped wafer.

[0064] [Figure 2] FIG. 1 illustrates an exemplary layout of optical sensors for an exemplary sensor-carrying wafer.

[0065] [Figure 3] FIG. 10 illustrates another example layout of optical sensors for an exemplary sensor wafer.

[0066] [Figure 4] FIG. 10 illustrates another example layout of optical sensors for an exemplary sensor wafer.

[0067] [Figure 5] 5A-5C illustrate the exemplary sensor-carrying wafer of FIG. 4 in different rotational positions.

[0068] [Figure 6-1] 1A-1C illustrate different stages of the movement of a wafer handling robot and a sensor-equipped wafer. [Figure 6-2] 1A-1C illustrate different stages of the movement of a wafer handling robot and a sensor-equipped wafer. [Figure 6-3] 1A-1C illustrate different stages of the movement of a wafer handling robot and a sensor-equipped wafer. [Figure 6-4] 1A-1C illustrate different stages of the movement of a wafer handling robot and a sensor-equipped wafer. [Figure 6-5] 1A-1C illustrate different stages of the movement of a wafer handling robot and a sensor-equipped wafer. [Figure 6-6] 1A-1C illustrate different stages of the movement of a wafer handling robot and a sensor-equipped wafer.

[0069] [Figure 7] FIG. 1 illustrates an exemplary sensor wafer with upward-facing optical sensors mounted on a rotatable support structure.

[0070] [Figure 8] 1A-1C are diagrams of an exemplary smaller diameter sensor-carrying wafer during various phases of use. [Figure 9] 1A-1C are diagrams of an exemplary smaller diameter sensor-carrying wafer during various phases of use. [Figure 10] 1A-1C are diagrams of an exemplary smaller diameter sensor-carrying wafer during various phases of use. [Figure 11] 1A-1C are diagrams of an exemplary smaller diameter sensor-carrying wafer during various phases of use.

[0071] [Figure 12] FIG. 3 illustrates the exemplary sensor-carrying wafer of FIG. 2, but additionally including an illumination device.

[0072] [Figure 13] FIG. 5 illustrates the exemplary sensor-carrying wafer of FIG. 4, but additionally including an illumination device.

[0073] [Figure 14] FIG. 1 illustrates an exemplary sensor-carrying wafer with an illumination pattern projection system.

[0074] [Figure 15] 15 illustrates the exemplary sensor-carrying wafer of FIG. 14 with an illumination pattern projection system being used with a showerhead having a non-planar underside.

[0075] [Figure 16] 16 shows a variation of the sensor-carrying wafer of FIGS. 14 and 15 with a second illumination device configured to project a reference illumination pattern. FIG.

[0076] [Figure 17] FIG. 1 illustrates an example of a sensor wafer with optical sensors configured with an outward radial field of view.

[0077] [Figure 18] FIG. 1 illustrates an example of a sensor wafer with optical sensors configured with radially outward fields of view mounted on a rotatable support structure.

[0078] [Figure 19A] FIG. 10 illustrates another exemplary sensor wafer with upward-facing optical sensors mounted on a rotatable support structure. [Figure 19B] FIG. 10 illustrates another exemplary sensor wafer with upward-facing optical sensors mounted on a rotatable support structure.

[0079] [Figure 20] FIG. 1 illustrates an exemplary sensor wafer with upward-facing optical sensors mounted on a rotatable support structure, which is in turn mounted on another rotatable support structure.

[0080] [Figure 21A] FIG. 1 is a diagram of a sensor wafer with multiple different sets of optical sensors. [Figure 21B] FIG. 1 is a diagram of a sensor wafer with multiple different sets of optical sensors. [Figure 21C] FIG. 1 is a diagram of a sensor wafer with multiple different sets of optical sensors. [Figure 21D] FIG. 1 is a diagram of a sensor wafer with multiple different sets of optical sensors. [Figure 21E] FIG. 1 is a diagram of a sensor wafer with multiple different sets of optical sensors.

[0081] [Figure 22A] FIG. 1 is a diagram of a sensor wafer with steerable optical sensors. [Figure 22B] FIG. 1 is a diagram of a sensor wafer with steerable optical sensors. [Figure 22C] FIG. 1 is a diagram of a sensor wafer with steerable optical sensors.

[0082] [Figure 23] FIG. 1 illustrates an example of a sensor wafer having a substrate supporting multiple ambient air sensors.

[0083] [Figure 24] FIG. 24 shows the same exemplary sensor-equipped wafer as in FIG. 23, but with differently shaded areas representing different partial pressures resulting from leaks.

[0084] [Figure 25] FIG. 1 illustrates an exemplary semiconductor processing tool (or portion thereof) that may be configured to utilize a sensor-equipped wafer.

[0085] [Figure 26] 1 is a schematic diagram of a portion of a semiconductor processing tool.

[0086] [Figure 27] FIG. 1 illustrates an example of a sensor wafer having a substrate supporting multiple microphone sensors.

[0087] [Figure 28] FIG. 1 illustrates an example of a sensor wafer having a substrate supporting multiple directional microphone sensors.

[0088] [Figure 29] FIG. 1 illustrates an example of a sensor wafer having a substrate supporting a rotatable support structure that supports directional microphone sensors. DETAILED DESCRIPTION OF THE INVENTION

[0089] Figures herein generally are not drawn to scale unless indicated below as being drawn to scale.

[0090] The inventors have devised several different types of sensor-mounted wafers or substrates that can be used to evaluate various aspects of the operational capabilities and / or performance of semiconductor processing tools. It will be understood that in many cases, features of the various implementations described can be implemented, for example, on a single wafer or substrate, along with features of other implementations described herein. Because many of the implementations described herein can utilize relatively small sensors (compared to the size of the wafer on which the sensors are supported), it will be readily understood that including multiple different sensor systems on a common wafer or substrate is feasible. In this disclosure, references to a wafer in the context of structures to which the sensors described herein can be attached will be understood to refer to a wafer or substrate, and the two terms may be used interchangeably herein. More generally, the sensors and associated hardware (e.g., controllers, power supplies, memory, etc. that may interface with such sensors) described below with respect to sensor-mounted wafers can also be attached to structures other than wafers or substrates, for example, to sheets or plates of material, e.g., composites or carbon fiber. The shape of the structure (also referred to herein as the “base structure”) to which such sensors and associated hardware are attached (either directly or indirectly) may be circular in shape, similar to, for example, a typical semiconductor wafer processed using a semiconductor processing tool, as described below, or may be other shapes, e.g., polygonal, elliptical, annular, square, triangular, etc. Some such structures may also be generally planar in nature, while other such structures may be non-planar in nature, e.g., slightly dome-shaped. References to sensor-mounted wafers in this disclosure will be understood to encompass similar devices that are not necessarily limited to the use of a wafer or substrate as a platform to which sensors and other hardware are attached (either directly or indirectly), such as devices using structures such as, but not limited to, the examples provided above. Accordingly, references herein to sensor-mounted wafers may be understood to generally also refer to sensor-mounted devices more generally.Similarly, references herein to the substrate of such a sensor-carrying wafer may be understood to refer more generally to structures such as those described above.

[0091] The sensor-equipped devices described herein may generally be designed to incorporate an independent power source, such as a rechargeable battery or other energy source. Such devices may also include one or more processors and one or more memory devices, as well as one or more communication interfaces, e.g., one or more wireless communication interfaces. The one or more processors may be configured, e.g., via instructions stored in the one or more memory devices, to acquire data from one or more sensors that may be operatively connected thereto, and store the data in the one or more memory devices for subsequent communication to, e.g., an external controller, e.g., a controller of a semiconductor processing tool. Such communication may be performed, e.g., via a physical connection with the wafer (e.g., via a cable or connector) or via a wireless connection with the wafer, e.g., via a Bluetooth or WiFi connection. It will be understood that this basic control and communication architecture may be used with a wide variety of different sensors and may be suitable for use in any of the examples described herein.

[0092] The sensor-mounted wafers described herein may also generally be designed to be transportable within and / or between semiconductor processing tools using the same equipment typically used to transport substrates or wafers during semiconductor processing operations. Accordingly, the sensor-mounted wafers may generally be sized to be of a similar size and shape to the substrates or wafers that would typically be processed using such equipment. For example, a sensor-mounted wafer for use with a semiconductor processing tool used for 300 mm diameter wafer processing operations may be sized to be 300 mm in diameter and, for example, have a maximum thickness of 5 mm to 6 mm or less. Such a sensor-mounted wafer may therefore be capable of being transported between at least two locations within a semiconductor processing tool by a wafer-handling robot, supported by a shelf in a buffer that may be sized to contact the edge of the wafer, loaded into and transported by a front-opening unified pod (FOUP), and transported through a slit valve aperture, wafer transfer passageway, or other relatively wide, thin aperture that may be provided to allow wafers or substrates to be introduced into or removed from a semiconductor processing chamber and / or semiconductor processing tool. In some implementations, the substrate used in the sensor-carrying wafer may be the same diameter as, for example, the semiconductor wafers typically processed in the semiconductor processing tool with which the sensor-carrying wafer is configured for use. For example, if the semiconductor processing tool is configured to process 300 mm diameter wafers, the substrate of the sensor-carrying wafer may also be 300 mm in diameter. The thickness of such a substrate may, in some cases, be similar to the thickness of such wafers, e.g., 0.75 mm to 1 mm.In other implementations, such substrates may be larger and / or thicker than wafers typically processed using the tool with which the sensor-equipped wafer is intended to be used; for example, for a tool designed to process 300 mm wafers, the substrate may be 2-4 mm thick or less and / or up to 400 mm in diameter, assuming the tool has sufficient clearance to still allow such oversized wafers to be inserted into and removed from one or more chambers of such a tool in a manner similar to how a 300 mm wafer would be inserted into and removed from such one or more processing chambers. For example, some semiconductor processing tools may be designed to allow wafers to be moved into and out of the tool, and between locations within the tool, using "carrier rings," which are generally thin, annular structures with an internal diameter that is nominally the same size as the diameter of the wafers they are designed to carry. The carrier ring may have multiple features that support the wafer from below, such as tabs that extend radially inward to locations within the wafer edge, or circumferential ledges along their inner periphery that are of a diameter smaller than the wafer diameter to allow for wafer transfer from location to location. In such systems, the semiconductor processing tool may have equipment configured to directly contact the carrier ring rather than the wafer. For example, lift pins or a wafer handling robot may be configured and / or positioned to contact the carrier ring rather than the wafer. In some cases, a carrier ring for a 300 mm diameter wafer may be as much as 25 mm thick and 400 mm in diameter, and it will be understood that some implementations of the sensor-equipped wafers described herein may therefore be configured to have an overall envelope that is larger than that described above, e.g., up to 400 mm in diameter and 25 mm thick (allowing sensors of greater thickness to be used).

[0093] It will also be appreciated that the sensor-carrying wafer may also have an overall height (including the substrate and components attached to or supported by it) that is greater than the height of a typical wafer being processed, for example. For example, such a sensor-carrying wafer may have an overall thickness of up to 25 mm if the gap of the tool in which it will be used supports it.

[0094] It will also be appreciated that sensor-carrying wafers, such as those disclosed herein, may also be sized sufficiently large that they are impractical for insertion into or withdrawal from a semiconductor processing tool or chamber through an interface through which wafers to be processed are normally routed. For example, such oversized sensor-carrying wafers may be provided to such semiconductor processing tools or chambers through an alternative, larger interface from the interface through which wafers to be processed are routed. In some cases, the top plate of the chamber or tool may be removed to allow the sensor-carrying wafer to be placed in the chamber or tool, or the chamber or tool may have a resting location or parking spot therein that can store the sensor-carrying wafer when not in use, thereby allowing the oversized sensor-carrying wafer to be used without having to insert the sensor-carrying wafer into the chamber or tool prior to each use and then remove the sensor-carrying wafer from the chamber or tool after each use.

[0095] In some implementations described herein, one or more optical sensors, e.g., imaging sensors, photodetectors, etc., may be located on a side of a substrate configured to face upward when placed in a semiconductor processing chamber. Such an upward-facing orientation may enable the optical sensor(s) to obtain data regarding visible characteristics of, for example, a showerhead used to distribute gases across a wafer that may be loaded into the semiconductor processing chamber. Such data may provide insight into one or more aspects of conditions in a portion of the semiconductor processing chamber. For example, the presence of a deposited film on the underside of the showerhead or wear around gas distribution ports on the underside of the showerhead may be detectable using such data. A determination may then be made regarding whether the showerhead should be cleaned and / or replaced based on the actual condition of the showerhead evidenced by such data. If the showerhead is experiencing, for example, a higher-than-expected rate of unwanted deposition and / or wear on its underside, such data may enable an operator of the semiconductor processing tool to potentially perform a cleaning or replacement operation on the showerhead earlier than would normally be scheduled (e.g., according to a typical replacement or cleaning schedule). If the showerhead is experiencing, for example, a lower-than-expected rate of unwanted deposition and / or wear on its underside, such data may allow an operator of the semiconductor processing tool to potentially delay a scheduled cleaning or replacement operation on the showerhead.

[0096] In some implementations described herein, one or more optical sensors may be disposed on a substrate such that they have a field of view directed along an axis that is parallel or at least somewhat parallel to the substrate, such that, for example, when the substrate is disposed within the semiconductor processing chamber, the one or more optical sensors may be used to acquire data regarding visible characteristics of, for example, a sidewall, a slit valve, or other component or portion of a semiconductor processing tool. Such an apparatus may be used, for example, to acquire data regarding visible characteristics of such a component or portion of the semiconductor processing chamber, e.g., a component or portion thereof disposed radially outward from where a semiconductor wafer would normally be located when undergoing semiconductor processing operations within the semiconductor processing chamber. Such data may allow the condition of such a component or portion of the semiconductor processing chamber to be evaluated for potential unwanted buildup (e.g., film buildup) and / or potential wear or damage to the component. This may be used to determine whether and / or when potential cleaning or component replacement operations may need to be scheduled.

[0097] In some implementations described herein, one or more humidity, gas level, temperature, and / or airflow velocity sensors may be located on a substrate configured to be placed in a semiconductor processing chamber. Such sensors may then be used to obtain measurement data related to ambient atmospheric conditions in the vicinity of the substrate. Measurement data from several such sensors may be used to evaluate airflow over a substrate at various locations, for example, in an equipment front-end module (EFEM), in a front-opening unified pod (FOUP), in a wafer buffer, in a load lock, or as it is being transferred by a wafer-handling robot within the EFEM. In other cases, measurement data from several such sensors may be used to determine the level of a particular type of gas, such as oxygen, that may be present in proximity to a substrate under vacuum or near-vacuum conditions within a semiconductor processing chamber. Such information may provide insight into whether there is a potential leak of atmospheric air into the semiconductor processing chamber above a certain limit. Such information may also be used in the context of a nitrogen-purged EFEM or other system operating at or near atmospheric pressure but with an atmosphere having a composition significantly different from normal atmospheric air, for example, an atmosphere that is all nitrogen (or nearly all nitrogen). In such cases, such data may provide insight into what the actual composition of such an atmosphere is.

[0098] FIG. 1 shows a schematic diagram of an exemplary sensor-carrying wafer 100 illustrating various exemplary systems or components that may be included therein. As previously mentioned, the various sensors 120 included in the sensor-carrying wafer 100 may be communicatively connected to a first controller 108, which may include one or more first processors 110 and one or more first memories or memory devices 112. The first controller 108 may also be electrically connected to a power source 104, e.g., a battery, a capacitor, or other power source. In some implementations, the power source 104 may be operably connected to a charging feature, e.g., by electrical contact pins located at a location that aligns with a charging feature located on a docking station used to store the sensor-carrying wafer 100 when the sensor-carrying wafer 100 is placed in the docking station. In the implementation shown in FIG. 1, a wireless charging feature 106 is shown, which may be, for example, an inductive charging coil, such as a Qi-compatible inductive charging coil or other suitable wireless charging interface. In such cases, the docking station used to store the sensor-carrying wafer 100 may have a compatible wireless charging interface configured to charge the sensor-carrying wafer 100 when the sensor-carrying wafer 100 is placed therein. The various elements of the sensor-carrying wafer 100 may be attached to or supported by the substrate 102, as previously described.

[0099] The first controller 108 may also be communicatively coupled to a first wireless communication interface 114, e.g., WiFi, Bluetooth, or other wireless communication interface, so that commands and / or data can be sent to and / or from the first controller 108 and, therefore, the sensor-onboard wafer 100. For example, a semiconductor processing tool interfacing with the sensor-onboard wafer 100 may include a second controller having one or more second processors and one or more second memories. The second controller may be communicatively coupled to a second wireless communication interface, which may be configured to interface with the sensor-onboard wafer's first wireless communication interface 114. Thus, the sensor-onboard wafer 100 may be capable of wireless communication with the semiconductor processing tool, allowing information, commands, and other data to be transmitted between the sensor-onboard wafer 100 and the semiconductor processing tool.

[0100] 1, or other similar architectures, may be connected with one or more sensors 120. The one or more sensors 120 may, for example, include multiple sensors, and in some implementations may include multiple sensors of multiple different types. It will be appreciated that the various components shown may be distributed to provide space for the various individual sensors 120 as may be needed for a given layout or configuration of sensors.

[0101] 2 shows an exemplary layout of optical sensors for an exemplary sensor-mounted device or wafer, e.g., a layout for a group of sensors 120 of sensor-mounted wafer 100. As seen in FIG. 2 , a substrate 202 is provided that may support various electronic systems, e.g., similar to substrate 102, that may be used to provide control, power, and communication functionality for the multiple sensors 120. Substrate 202 (and other substrates described herein) may generally be described as a nominally planar structure having a first side and a second side opposite the first side. The first side of substrate 202 may be configured to rest on an end effector of a wafer-handling robot used to transfer wafers between locations within a semiconductor processing tool, for example, and the second side may generally be oriented facing upward during transfer within the semiconductor processing tool. Alternatively, the first side of substrate 202 may be configured to rest on some other type of object handling system or apparatus of the semiconductor processing tool, such as a rotary indexer, an autonomous robot capable of freely navigating within the chamber or tool, etc. As seen in Figure 2, optical sensors 222 (one example of a sensor that may be included in plurality of sensors 120) are distributed across the upper surface (second side) of substrate 202 such that each optical sensor 222 has a field of view that encompasses an area 223 on a reference plane that is offset by a distance X upward and perpendicular to substrate 202. Thus, optical sensors 222 may have an upward-facing field of view when the sensor-carrying wafer is oriented with the first side of the sensor-carrying wafer facing downward. When the substrate 202 is supported in a semiconductor processing chamber with the top surface of the substrate 202 facing upward, e.g., a distance X from the underside of the showerhead 252 (the periphery of which is represented in FIG. 2 by the dashed circle 252) of the semiconductor processing chamber, a majority of the underside of the showerhead 252 will be within the field of view of the optical sensor 222. Distance X can be between 70 mm and 100 mm, e.g., between 80 mm and 90 mm, e.g., about 85 mm, in some implementations.

[0102] This arrangement may enable the optical sensor 222 to acquire optical data regarding a large portion of the underside of the showerhead 252. Thus, for example, if the optical sensor 222 is an imaging sensor, e.g., a digital camera, the combined region of the field of view on the reference plane may cover an area equal to 50%, 60%, 70%, 80%, or 90%, or even 100%, of the underside of the showerhead 252. If the fields of view 223 of such imaging sensors overlap at a focal plane parallel to and a first distance from the second side of the substrate 202, the images acquired from these imaging sensors may be digitally combined to form a single, larger image of the focal plane. For example, if the focal plane coincides with, e.g., the underside of the showerhead at a distance X, such a combined image may show the entire, or nearly the entire, underside of the showerhead 252. Even if the fields of view 223 do not necessarily overlap at such a focal plane, the individual images may still provide insight into the condition of the showerhead 252.

[0103] In some implementations, the plurality of optical sensors 222 may be configured such that the area resulting from the intersection of the focal plane and the field of view of the optical sensor 222 is, for example,

number

[0104] 2, the optical sensors 222 may be arranged in a triangular array, for example, with the centers of the optical sensors 222 located at the vertices in an equilateral triangular grid or lattice. This may be suitable for optical sensors that capture images of an entire circular field of view and may generally allow the smallest number of optical sensors to completely cover a given circular area or region. For optical sensors that capture images of a rectangular subportion of a circular field of view, the optical sensors may be arranged in a rectangular, parallelogram, or other pattern while still allowing the smallest number of optical sensors to be used to cover a given circular area.

[0105] 3 , an additional optical sensor 222′ may be placed in a position that is not aligned with any particular repeating pattern to provide additional imaging coverage and expand the composite field of view provided by optical sensor 222. As can be seen, such an arrangement, including placing optical sensor 222′ near the periphery of substrate 202, may allow the composite field of view provided by field of view 223 to extend further beyond the footprint of substrate 202. This may allow optical sensors 222 and 222′ to be used to acquire composite images of both the underside of showerhead 252 immediately above substrate 202, as well as a peripheral region of the underside of showerhead 252 that extends beyond the periphery of substrate 202.

[0106] The imaging sensors used in the sensor-mounted wafers can be similar to those used in, for example, smartphones and other small electronic devices. For example, camera modules including integrated optical lens systems (e.g., single-lens or multi-lens optical systems that can have a field of view of 30° or more, e.g., 40° or more, 50° or more, 60° or more, 70° or more, 80° or more, or even up to 180° or more, and a depth of focus on the order of 2 mm to 100 mm) designed for integration into smartphones and other portable electronic devices are widely available and can have thicknesses on the order of 5 mm or less, allowing them to be integrated into the sensor-mounted wafers while still allowing the sensor-mounted wafers to have an overall maximum thickness of on the order of 25 mm. Such thickness allows the sensor-mounted wafers to be handled in semiconductor processing tools in the same manner as regular wafers to be processed, without risking collisions with semiconductor processing chamber components or other wafers that may be present in the semiconductor processing chamber. In some implementations, the imaging sensors used in the sensor-mounted wafers can be coupled to optical lens systems that provide a field of view of between 30° and 180°.

[0107] It will be appreciated that when an imaging sensor is used as an optical sensor, such an imaging sensor can be used to acquire either still or continuous image data, i.e., video data, that may show the appearance of one or more components over time. For example, if a sensor-mounted wafer having one or more imaging sensors is oriented within a semiconductor processing chamber such that a slit valve or gate valve of that chamber is within the field of view of one or more such imaging sensors, the sensor-mounted wafer can be caused to acquire video footage from within the chamber of the slit valve or gate valve opening and / or closing, which can provide insight into potential mechanical problems with the operation of such components. In another example, such an imaging sensor can be used to acquire video footage of, for example, the placement of an edge ring within a semiconductor processing chamber.

[0108] In some implementations, other arrangements of optical sensors may be used. Figure 4 shows an exemplary optical sensor arrangement in which optical sensors 422 are disposed across only a portion of the substrate 402, e.g., spaced along a radius of the substrate 402. Alternatively, such optical sensors 422 may be located at different radial distances from the center of the substrate 402, although not necessarily along the same radius. In some such implementations, the optical sensors 422 may be arranged such that the center of each optical sensor 422 is located at radial distances from the center of the substrate 402 in increments of 8 mm to 12 mm, e.g., 10 mm. For example, if the substrate 402 is a sensor-mounted wafer having a diameter of 300 mm, there may be on the order of 12 to 17, e.g., 13 to 16, or 14 to 15, optical sensors 422, each positioned at a different radial distance from the center of the substrate 402 and arranged so that the radial distances are generally uniformly distributed (e.g., each radial distance is between X mm and Y mm greater than the next higher radial distance, with X and Y being on the order of 8 mm to 13 mm). Such an arrangement reduces the amount of wafer area that may need to be used to accommodate the optical sensors 422, thereby leaving additional space for accommodating other components, such as, for example, the various systems described with respect to FIG. 1 . A lower number of optical sensors 422 may also result in reduced cost and lower power consumption. In some embodiments, other types of sensors (e.g., ambient air sensors or sound sensors) may occupy the area not occupied by the optical sensors.

[0109] Such an arrangement may be suitable for use in semiconductor processing tools where it is not necessary to acquire images of most of the underside of the showerhead 452. For example, if the showerhead in a given semiconductor tool is known to always have a circumferentially uniform or nearly circumferentially uniform layer of unwanted deposition film that gradually builds up on its underside over time, one or more images along a given radius of the sensor-equipped wafer 400 may be sufficient to get a sense of what the film deposition is like across the entire underside of the showerhead. Similarly, if there are portions or locations on the underside of the showerhead that are known to experience accelerated levels of deposition compared to other portions of the underside of the showerhead, the sensor-equipped wafer 400 may include one or more optical sensors, e.g., imaging sensors, that may be positioned to be placed directly under such one or more locations or to image an area including such one or more locations.

[0110] It will be appreciated that an optical sensor arrangement such as that shown in Figure 4 may also be used in some contexts to obtain images of a larger portion of the underside of the showerhead than can be imaged at one time by the sensor-equipped wafer of Figure 4. For example, as shown in Figure 5, the sensor-equipped wafer shown in Figure 4 may be caused to rotate relative to the showerhead 452 while data about the underside of the showerhead is obtained using the optical sensor 422.

[0111] FIGS. 6-1 through 6-6, or examples, illustrate various stages in one example of such a technique. In FIG. 6-1, a wafer-handling robot 454 is caused to reach into a semiconductor processing chamber 450 to retrieve a sensor-mounted wafer 400. Prior to such removal, the sensor-mounted wafer 400 is caused to acquire data via an optical sensor 422 having a field of view 423 extending across a portion of the underside of a showerhead 452. The darker shaded portions of the showerhead 452 represent the area of the showerhead 452 from which the data was acquired. The sensor-mounted wafer 400 may be supported on a pedestal (not shown) within the semiconductor processing chamber 450 while the data is being acquired, and then may be lifted from the pedestal using multiple lift pins. Once the sensor-mounted wafer 400 is in the lifted position, the wafer-handling robot 454 may be caused to position a portion of its end effector 456 beneath the sensor-mounted wafer 400. The lift pins can then be caused to retract into the pedestal, lowering the sensor-equipped wafer 400 onto the end effector 456 .

[0112] 6-2, the wafer handling robot 454 was controlled to remove the sensor-mounted wafer 400 from the semiconductor processing chamber 450 and cause the sensor-mounted wafer 400 to be placed on the rotatable wafer support 460 of the aligner 458, or other mechanism configured to allow rotational reorientation of a wafer placed thereon. As can be seen, the darker shaded areas in the shape of three overlapping circles within the semiconductor processing chamber 450 continue to represent areas of the showerhead 452 where data was acquired using the optical sensor 422.

[0113] In FIG. 6-3 , the wafer-handling robot is caused to withdraw the end effector 456 from beneath the sensor-carrying wafer 400, leaving the sensor-carrying wafer 400 supported solely by the rotatable wafer support 460. For example, the rotatable wafer support 460 may have three pins extending vertically upward therefrom. The three pins may serve to support the sensor-carrying wafer 400 when the sensor-carrying wafer 400 is placed on them, but may also be tall enough that the gap between the rotatable wafer support 460 and the underside of the sensor-carrying wafer 400 when the sensor-carrying wafer 400 is supported by the pins is sufficient to allow clearance for the wafer-handling robot to move the end effector 456 up and down to contact or separate from the sensor-carrying wafer 400 and to allow the end effector 456 to be withdrawn from or inserted into the gap between the rotatable wafer support 460 and the sensor-carrying wafer 400.

[0114] In FIG. 6-4, the aligner 458 has been caused to rotate the rotatable wafer support 460 by a first angular amount, e.g., 30°, relative to the aligner 458. As can be seen, this causes the optical sensor 422 to be repositioned such that when the wafer handling robot 454 is caused to move the end effector 456 back under the sensor-carrying wafer 400, as shown in FIG. 6-5, the optical sensor 422 is at a different angular orientation relative to the end effector 456 compared to the rotational orientation the optical sensor 422 was in relative to the end effector 456 in FIG. 6-2.

[0115] In FIG. 6-6, the wafer handling robot 454 is caused to place the rotated sensor-equipped wafer 400 back into the semiconductor processing chamber 450. As can be seen, the optical sensor 422 has a field of view 423 that now covers a different region of the underside of the showerhead 452 (although the optical sensor 422 at the center of the sensor-equipped wafer 400 will again image the same region). It will be understood that the process illustrated in FIGS. 6-1 through 6-6 can be repeated as needed to acquire data from the optical sensor 422 for different regions of the underside of the showerhead 452, or for all or substantially all of the underside of the showerhead 452. For example, if the optical sensor 422 is an imaging sensor, the techniques described above can be used to acquire multiple sets of images with the sensor-equipped wafer 400 at different angular orientations to enable a single composite image of the underside of the showerhead 452 to be acquired. In some implementations, the sensor-mounted wafer 400 may be rotated by a larger rotational amount between acquiring data from one or more optical sensors, for example, an amount large enough that there is a gap between regions of the showerhead 452 where data is acquired for nearest adjacent rotational positions.

[0116] In other implementations, multiple sets of optical sensors 422 are present on the sensor-mounted wafer so that data for a larger portion of the underside of the showerhead 452 can be acquired at a given rotational position, thereby allowing the sensor-mounted wafer 400 to be rotated fewer times, and by a smaller total amount, to acquire a desired level of data coverage for the underside of the showerhead 452. For example, if the sensor-mounted wafer 400 of FIGS. 6-1 through 6-6 instead had an array of optical sensors 422 that extended across the entire diameter of the sensor-mounted wafer 400 (rather than just along its radius), data for a given portion of an annular region around the central field of view could be acquired using the optical sensors 422, requiring half the number of rotations that would be required with the arrangements shown in FIGS. 6-1 through 6-6.

[0117] It will also be appreciated that the optical sensors 422 need not be arranged in a row, as shown in FIGS. 6-1 through 6-6, to use the techniques described above. In some implementations, it may be sufficient to have at least one optical sensor 422 with a field of view that is off-center of the sensor-mounted wafer 400, so that when the sensor-mounted wafer 400 is angularly reoriented, the off-center optical sensor 422 rotates to a new rotational orientation, but also to a new XY position relative to a coordinate system fixed relative to the showerhead 452. In some such implementations, there may be multiple optical sensors 422, each positioned at a different radial distance from the center of the sensor-mounted wafer 400; thus, when the sensor-mounted wafer 400 is continuously rotated in position below the showerhead 452, each such optical sensor 422 may be used to obtain data regarding the visible characteristics of a different annular region on the underside of the showerhead 452.

[0118] It will be appreciated that in some implementations, the sensor-mounted wafer 400 may never actually be placed on a pedestal in the semiconductor processing chamber. For example, the wafer-handling robot 454 may simply support the sensor-mounted wafer 400 at all times within the semiconductor processing chamber 450. Thus, the wafer-handling robot 454 may be caused to position the sensor-mounted wafer 400 within the semiconductor processing chamber 450 in a centered position below the showerhead 452, and the sensor-mounted wafer 400 may then be caused to acquire data regarding the visible characteristics of the underside of the showerhead 452. The wafer-handling robot 454 may then withdraw the sensor-mounted wafer 400 from the semiconductor processing chamber 450 and place it on a mechanism that may be used to cause the sensor-mounted wafer to rotate, after which the wafer-handling robot 454 may again remove the sensor-mounted wafer 400 and insert it into the semiconductor processing chamber 450. The sensor-equipped wafer 400 may then again be caused to acquire further data regarding the visible properties of different portions of the underside of the showerhead 452 , with the sensor-equipped wafer 400 being supported by the wafer handling robot 454 .

[0119] It will be further appreciated that rotation of the sensor-mounted wafer 400 between each acquisition of data using the optical sensor(s) 422 may, in some implementations, be performed using equipment different from the aligner 458. For example, in some implementations, a pedestal that may be used to support the sensor-mounted wafer 400 in the semiconductor processing chamber 450 may be equipped with rotation capabilities. In such implementations, the pedestal may simply be rotated while supporting the sensor-mounted wafer 400, either directly or indirectly. Such implementations allow the sensor-mounted wafer 400 to be rotated relative to the showerhead 452 without requiring the sensor-mounted wafer 400 to be removed from the semiconductor processing chamber 450 between rotation operations.

[0120] In another example, some wafer handling systems may have built-in wafer rotation capabilities. For example, in some multi-station semiconductor processing chambers, multiple pedestals, e.g., four, may be arranged in a circular array. Such semiconductor processing chambers may have a rotational indexer, e.g., a device with a rotatable central hub having four equal-length rigid arms extending outwardly therefrom at equally spaced positions around the central hub. Wafer supports located at the distal ends of the arms may be positioned so that each wafer supported thereby can be caused to move from a location centered on the center of each of the pedestals to a location centered on the center of each of the other pedestals within the semiconductor processing chamber 450.

[0121] In some rotary indexers, the rotary indexer may include a mechanism that allows the wafer support at the end of the rotary indexer arm to be rotated relative to the arm, for example, while the rotary indexer is possibly stationary. Thus, for example, the rotary indexer may be rotated to position one of its wafer supports under the sensor-carrying wafer 400 (the sensor-carrying wafer 400 may be lifted from the pedestal below it, e.g., by lift pins, to allow clearance for the wafer support to be so positioned). The sensor-carrying wafer 400 may then be placed on the wafer support, and the wafer support may be caused to rotate. The sensor-carrying wafer 400 may then be removed from the wafer support, e.g., by being lifted upward by lift pins in the pedestal, and the indexer may be rotated to move the wafer support out from under the sensor-carrying wafer, thereby allowing the wafer to be lowered onto the pedestal in its new rotational orientation, for example. Such indexers, with the ability to rotate the wafer without rotating the indexer arm, may in some cases be able to rotate a wafer placed thereon by any angle between 0° and 90°, enabling a variety of sensor-equipped wafer rotation options.

[0122] In further implementations, the sensor-carrying wafer may itself include the ability to rotate one or more optical sensors relative to its substrate, as shown in FIG. 7 . In FIG. 7 , a sensor-carrying wafer 700 is shown having a substrate 702. The substrate 702 has a support structure 764 rotatably mounted relative to the substrate 702. The substrate 702 may also support a rotational drive 766, e.g., a motor or other system, configured to cause the support structure 764 to rotate relative to the substrate 702 by at least a first amount of rotation. In some implementations, the first amount of rotation may be less than 360°, while in other implementations, the first amount of rotation may be 360° (or more).

[0123] The one or more optical sensors 722 may be supported by the support structure 764 and oriented such that they have a field of view 723 facing upward, e.g., along a direction generally parallel to the axis of rotation about which the support structure 764 is configured to rotate. At least one of the one or more optical sensors 722 may be supported by the support structure 764, e.g., at a location radially offset from the axis of rotation by at least a distance, e.g., perpendicular thereto, such that rotation of the support structure 764 causes the field of view 723 of at least one of the first optical sensors supported by the support structure 764 to orbit about the axis of rotation of the support structure 764. In some such implementations, there may be multiple such first optical sensors 722, each positioned at a different distance from the axis of rotation, thereby enabling imaging of different annular zones of the underside of the showerhead 752 as the support structure 764 is rotated. For example, in FIG. 7, there are three such first optical sensors 722 positioned at three different distances from the axis of rotation of the support structure 764. When the support structure 764 is caused to rotate by the rotary drive 766, the first optical sensors 722 orbit about the axis of rotation at different distances, thereby each having a field of view 723 that sweeps across one of several different annular zones on the underside of the showerhead 752.

[0124] In some implementations, other electronics for the sensor-mounted wafer 700, such as a controller, power supply, communication interface, etc., may also be mounted to the support structure 764 such that all of those electronics rotate with the support structure 764. In other implementations, however, at least some of the other electrical components of the sensor-mounted wafer 700 may be mounted on the substrate 702. In such implementations, the one or more optical sensors 722 may be electrically connected, either directly or indirectly, to one or more of the electrical components mounted to the substrate 702, for example, via a flexible cable. Alternatively, such electrical connection may be provided, for example, via a conductive path integrated into a bearing assembly used to rotatably support the support structure; for example, the electrical connection may be provided by a slip ring connection.

[0125] In such a sensor-equipped wafer, the controller can be controlled to cause one or more control signals to be provided to the rotational drive 766. The control signals can cause the rotational drive 766 to rotate, thereby causing the support structure 764 (and the optical sensor(s) 722 attached thereto) to rotate relative to the substrate 702. Through such rotation, the optical sensor(s) 722 can be caused to shift between different rotational positions relative to the substrate 702, thereby allowing data about different regions of the underside of the showerhead 752 to be collected using the optical sensor(s) 722. In some implementations, such data can be acquired continuously from the optical sensor(s) 722, and the support structure 764 can be caused to rotate along with the optical sensor(s) 722, effectively acting as a rotary scanner. In other implementations, the optical sensor(s) 722 can be caused to acquire such data during rotation of the support structure 764.

[0126] In some implementations, a sensor-equipped wafer configured for use in a particular semiconductor processing tool may incorporate a substrate sized smaller than the size of wafers that the semiconductor processing tool is configured to process. For example, if the semiconductor processing tool is configured to process 300 mm wafers, such a sensor-equipped wafer may be, for example, 200 mm or less, 150 mm or less, or 100 mm or less in diameter. Such a sensor-equipped wafer may have a substrate diameter that is, for example, 60% or less, e.g., 50%, of the nominal wafer diameter of wafers typically processed in the semiconductor processing chamber in which such a sensor-equipped wafer is intended to be used. For example, in some cases, an end effector that supports a semiconductor wafer during wafer transfer operations in a semiconductor processing tool (and that would also be used to transfer the sensor-equipped wafer) may contact a 300 mm wafer over a 50 mm diameter contact area, in which case the sensor-equipped wafer may have a diameter as low as 17% of the nominal diameter of wafers typically processed in the semiconductor processing chamber and still be supported by the end effector.

[0127] In such implementations, the smaller substrate size would limit the space available to support the optical sensors, but such a sensor-carrying wafer may provide additional positioning flexibility due to its smaller size. FIGS. 8-11 show diagrams of a smaller diameter sensor-carrying wafer. In FIGS. 8-11, a semiconductor processing chamber 850 is shown that includes a showerhead 852. A wafer footprint 872 is shown below the showerhead 852, representing the general location / footprint of a semiconductor wafer within the semiconductor processing chamber during wafer processing operations. A wafer handling robot 854 is shown with an end effector 856 used to support the sensor-carrying wafer 800. The sensor-carrying wafer 800 has a substrate 802 that supports several optical sensors 822 with upward-facing fields of view 823. In this example, there are seven optical sensors 822, but it will be appreciated that more or fewer optical sensors may be used.

[0128] It is noted that the substrate 802 has a diameter smaller than the diameter of wafers typically processed in the semiconductor processing chamber 850, as indicated by the difference in size between the wafer footprint 872 and the substrate 802. This allows the sensor-equipped wafer 800 to be moved between different positions within the semiconductor processing chamber, as shown in Figures 8-11, for example, so that data regarding the visible properties of different portions of the showerhead 852 can be obtained. Such an arrangement may allow such a sensor-equipped wafer to obtain optical data regarding an area of the showerhead that is much larger than the aggregate field of view of the optical sensors stored on such a sensor-equipped wafer.

[0129] It will be understood that in such implementations, the sensor-equipped wafer may have more or fewer optical sensors than the seven shown. The sensor-equipped wafer may even have only a single optical sensor (or a single optical sensor of a particular type of optical sensor). In some implementations, a controller of a semiconductor processing tool, for example, having one or more processors and one or more memory devices, may be controlled via computer-executable instructions stored therein to control a wafer-handling robot to retrieve such a sensor-equipped wafer, for example, from a storage location or other location outside a semiconductor processing chamber of the semiconductor processing tool, and then insert it into a semiconductor processing chamber of the semiconductor processing tool. The instructions may further cause the wafer-handling robot to move the sensor-equipped wafer between different locations within the semiconductor processing chamber and send one or more commands to the sensor-equipped wafer to cause the sensor-equipped wafer to acquire data regarding visible characteristics of the underside of the showerhead at each such location. Such optical data may then be retrieved from the sensor-equipped wafer, analyzed, and used, for example, to generate a composite image of the underside of the showerhead.

[0130] As mentioned above, the optical sensor used may be an imaging sensor, such as, for example, a charge-coupled device (CCD) or other pixel-based imaging sensor. Such optical sensors may, in some cases, be used without an external illumination source. In other implementations, a sensor-mounted wafer having one or more optical sensors may also include one or more illumination devices or systems that may be configured to provide a desired form of illumination. In some such examples, an illumination source (e.g., a light source) may be used that provides diffuse, relatively uniform light across a surface from which data will be acquired using the optical sensor(s). For example, one or more light-emitting diodes, electroluminescent panels, or other light-emitting structures may be attached to a side of sensor-mounted wafer 400 facing toward showerhead 452 so that light, e.g., light in a specific light spectrum or a broad spectrum, e.g., white light, may be directed upward by sensor-mounted wafer 400 toward the underside of showerhead 452. In some such implementations, a diffuser material, e.g., a diffusing optically transmissive medium, may be placed over the light-emitting structure to distribute the illumination more uniformly and prevent or mitigate potential specular reflections that may obscure visible features intended to be captured by the optical sensor(s).

[0131] 12 and 13 illustrate examples of sensor-carrying wafers similar to those described with respect to FIGS. 2-5, but with the addition of illumination sources that can be used to illuminate the surface from which the optical sensors (imaging sensors) are configured to acquire optical data. For example, FIG. 12 illustrates the sensor-carrying wafer 200 of FIG. 2, but with the addition of illumination devices 224 arrayed across the upper surface of the substrate 202. The illumination devices 224, in this example, are electroluminescent panels or LEDs that are generally triangular in shape and positioned so that the corners of each triangular panel are generally adjacent to different ones of the optical sensors 222. Such illumination devices 224 can be caused to be illuminated to direct light toward the surface of anything located on the sensor-carrying wafer, such as toward the underside of the showerhead 252. As mentioned above, the illumination devices 224 may, in some cases, include a layer of diffusing material that serves to diffuse the light emitted from the illumination devices 224, thereby mitigating or preventing specular reflections from the surface being imaged.

[0132] 13 shows the sensor-carrying wafer 400 of FIG. 4 but with the addition of illumination devices 424, which in this example are rectangular electroluminescent panels or LEDs disposed on either side, between, and across the three optical sensors 422 shown. Such illumination devices may, in some cases, include a layer of diffusing material, as in the example of FIG. 12.

[0133] In some implementations of the sensor-carrying wafer with illumination source, an illumination source may be provided that projects a structured image onto the sensor-carrying wafer 4002 (with the first side of the substrate 402 facing toward and / or in contact with the pedestal and the second side of the substrate 402 facing upward toward the showerhead) along an axis that is at an oblique angle to the substrate 402, e.g., an axis that is at an oblique angle to the second side of the substrate 402. For example, an illumination source that projects a straight line that is parallel to and coincident with a plane that is at an oblique angle to the substrate 402 may be used. Such an illumination source may be provided, for example, using a laser diode coupled to a diffractive optical element that scatters collimated light produced by the laser diode into a line. When such an illumination pattern is projected onto a reference plane that is parallel to the substrate 402 (and farther from the first side of the substrate than the second side of the substrate), the projected light will intersect the reference plane along a line. Thus, if the reference plane is, for example, the underside of the showerhead 452, and the underside of the showerhead 452 is flat and parallel to the substrate 402, then light striking the underside of the showerhead 452 will form a straight line. Figure 14 shows a schematic of this.

[0134] 14 has an upper portion showing a side view of a sensor-carrying wafer 1400 supported by a pedestal 1462 below a showerhead 1452, and a lower portion showing a top view of the same structure. The sensor-carrying wafer 1400 includes a substrate 1402 having mounted thereon a plurality of optical sensors 1422 arranged along the diameter of the sensor-carrying wafer 1400. Also supported by the substrate 1402 is an illumination device 1424, which in this example is a laser diode coupled to a diffractive optical element that spreads a collimated beam of light emitted by the laser diode into a two-dimensional fanned-out optical beam 1426. The fanned-out optical beam is parallel to and coincides with a plane that is normal to the page, i.e., parallel to the Y-axis of the coordinate system shown, and parallel to the dotted line representing the optical beam 1426.

[0135] 14, when the underside of the showerhead 452 is flat and perfectly parallel to the substrate 1402, the fan-out optical beams will produce an illumination pattern 1428 that is a straight line. Optical sensors 1422, which may be imaging sensors, can be disposed on the substrate 1402 such that the illumination pattern 1428 is within a collective field of view 1423 of the optical sensors 1422. Thus, if an image of the underside of the showerhead 1452 is captured by the optical sensors 1422 while the illumination pattern 1428 is projected onto the underside of the showerhead 1452, the resulting composite image will show the illumination pattern 1428 as a straight line.

[0136] However, if the underside of the showerhead 1452 where the optical beam strikes is uneven due to deposition occurring on the underside of the showerhead 1452, the fan-out optical beam will strike the underside of the showerhead at a different location than that shown in Figure 14. For example, Figure 15 is the same as Figure 14, except that the underside of the showerhead 1452 has a slight bulge relative to it, as may be caused by deposition on the underside of the showerhead 1452 that is thickest near the center of the showerhead and then decreases in thickness near the edges of the showerhead 1452, for example.

[0137] As a result of that bulge, the optical beam 1426 striking the underside of the showerhead 1452 strikes it at a different location than it would in the ideal case, as shown, for example, in FIG. 14 . This is because the optical beam strikes the underside of the showerhead at a shallow angle, and changes in the altitude at which the optical beam strikes the underside of the showerhead will generally also result in a lateral (XY shift) in the location of the intersection point. With the shallow dome-shaped profile of the underside of the showerhead 1452 shown in FIG. 15 , the previously straight illumination pattern shown in FIG. 14 instead appears as a slightly curved illumination pattern 1428′. The amount of maximum deviation from the straight illumination pattern 1428 to the curved illumination pattern 1428′ indicates the amount of maximum non-uniformity present in the thickness of the deposited material on the underside of the showerhead 1452.

[0138] In some implementations, a second illumination pattern can be provided using a second illumination device. The second illumination pattern can be projected onto the underside of the showerhead in a manner that minimizes or eliminates the amount of distortion that the second illumination pattern can undergo when projected onto the underside of the showerhead 1452 when the underside is not flat and / or not parallel to the substrate 1402.

[0139] 16 shows the same elements as shown in FIG. 15 , except that the sensor-mounted wafer 1400 further includes a second illumination device 1424′ configured to project a reference illumination pattern 1430 onto the underside of the showerhead 1452 in a manner that renders it generally free from distortions similar to those experienced by the illumination pattern 1428′. For example, the reference illumination pattern 1430 may similarly be a fan-out optical beam from a laser diode, but the fan-out beam may be projected so that it is perpendicular to the substrate 1402 and parallel to a line formed by the intersection of the illumination pattern 1428 with a plane, e.g., a reference plane, that is parallel to the substrate 1402. Thus, the fan-out optical beam forming the reference illumination pattern 1430 may effectively act as a vertical plane that intersects the underside of the showerhead 1452, but that vertical plane does not experience a shift in intersection location in a direction perpendicular to the vertical plane. As a result, the reference illumination pattern 1430 will remain linear and may provide a basis for comparison with the illumination pattern 1428'. As can be seen, the optical sensor 1422 may be arranged to be able to simultaneously image both the reference illumination pattern 1430 and the illumination pattern 1428. If the illumination pattern 1428' is linear, as shown, for example, by the illumination pattern 1428 in FIG. 14, the illumination pattern 1428 and the reference illumination pattern 1430 may be parallel or even collinear, depending on the positioning of the two patterns.

[0140] It will be appreciated that the illumination pattern 1428 can take any of a variety of different forms, including, for example, a rectangular grid pattern, a rectangular array of “+” symbols, a rectangular array of dots, a pattern of concentric circles, a rectangular pattern of circles, etc. The illumination pattern can also be a non-repeating arrangement of shapes. While the single line pattern used in FIGS. 14-16 provides an easily understood example, it will be apparent that, in general, any illumination pattern projected onto the underside of the showerhead 1452 at an oblique angle will be distorted when projected onto a non-planar showerhead underside compared to a planar showerhead underside, and the amount of such distortion, as imaged by the optical sensor 1422 positioned generally directly below the location where the illumination pattern strikes the underside of the showerhead 1452, will provide insight into the deviation of the showerhead underside from a perfectly flat surface parallel to the substrate 1402.

[0141] It will be further recognized that determining what level of deviation there is in a given illumination pattern due to an uneven underside of the showerhead 1452 can be accomplished through various mechanisms. For example, the illumination pattern recorded by the optical sensor(s) of the sensor-mounted wafer 1400 can be compared to a known or expected illumination pattern; e.g., if it is known that the illumination pattern 1428 should produce a straight line, the illumination pattern recorded by the optical sensor can be evaluated to determine how much it deviates from a straight line.

[0142] In other implementations, as described above, a reference illumination pattern that is not subject to distortion (in at least one direction) due to variations in the contour of the underside of the showerhead 1452 may also be projected onto the underside of the showerhead 1452 such that the optical sensor 1422 can be used to acquire image data of both the illumination pattern 1428 and the reference illumination pattern 1430, thereby enabling a direct comparison between the two imaged patterns. It will be appreciated that the reference illumination pattern 1430 and the illumination pattern 1428 may be projected onto the underside of the showerhead 1452 at different, non-overlapping times to separate the captured images of each pattern. If the sensor-equipped wafer is not moved while taking such pictures, it may be relatively straightforward to use the two images to assess the amount of deviation between the two patterns.

[0143] In still further implementations, the sensor-equipped wafer can be used to acquire an initial calibration image of the underside of the showerhead 1452 while an illumination pattern is projected thereon. Such a calibration image can be acquired while the showerhead 1452 is still in its original state, for example, before the showerhead 1452 is first exposed to a gas that may deposit a film on its underside, thereby potentially changing the contour of the underside of the showerhead 1452. This calibration image can then be retained and compared to future images of the projection of such an illumination pattern onto the underside of the showerhead with the sensor-equipped wafer disposed in the same location and orientation within the semiconductor processing chamber. Deviations between the illumination pattern shown in the calibration image and the illumination pattern shown in a later image, for example, acquired after the underside of the showerhead has experienced a change in the underside contour due to incidental deposition, can then be identified and quantified to provide an indication of the degree of non-uniformity of the underside of the showerhead.

[0144] In some implementations, one or more optical sensors may be provided on a sensor-mounted wafer, and the one or more optical sensors may be oriented so that they have a field of view directed radially outward, for example, toward a sidewall of a semiconductor processing chamber or toward a component located at the sidewall of the semiconductor processing chamber. FIG. 17 illustrates an example of a sensor-mounted wafer with optical sensors configured with a radially outward field of view. In FIG. 17 , a substrate 1702 for a sensor-mounted wafer 1700 is shown. Multiple optical sensors 1722 are disposed at spaced locations along the periphery of the substrate 1702 and are oriented so that they have fields of view 1723 directed radially outward from the substrate 1702. In the illustrated example, the optical sensors 1722, which may be imaging sensors, are spaced apart so that they have overlapping fields of view 1723 circumferentially at a given radial distance from the center of the sensor-mounted wafer 1700. For example, the field of view 1723 may overlap circumferentially at a radial distance from the center of the sensor-mounted wafer 1700 equal to the distance between the inner wall surface of the semiconductor processing chamber 1750 in which the sensor-mounted wafer 1700 is disposed and the center of the sensor-mounted wafer 1700 (or the distance between the inner wall surface and the central axis of the pedestal on which the sensor-mounted wafer 1700 is disposed when placed in the semiconductor processing chamber).

[0145] When positioned in such a manner, data, e.g., image data, acquired from optical sensor 1722 can be processed to provide a single data set representing optical data acquired from the entire circumference of a portion of one or more interior walls of the semiconductor processing chamber (or other structure, e.g., a slit valve through which a wafer may be introduced / removed from the semiconductor processing chamber). Thus, for example, a single composite panoramic image of the interior wall surface of semiconductor processing chamber 1750 can be acquired using such a sensor-equipped wafer.

[0146] It will also be appreciated that the spacing between the optical sensors 1722 may be large enough that some or all of the fields of view 1723 of the optical sensors 1722 do not overlap in such a manner, and therefore there may be areas of the interior wall surface of the semiconductor processing chamber 1750 from which data is not acquired from the optical sensor(s) 1722. In some implementations, the optical sensor(s) 1722 may be placed at one or more locations, where the sensor-mounted wafer 1700 is then placed in the semiconductor processing chamber 1750 in a predefined orientation, aligned with and oriented toward one or more locations from which data from the optical sensor(s) 1722 is desired. Such locations may include, for example, locations where elevated levels of unwanted deposition (or other semiconductor processing by-products or effects) are known or expected to occur, or areas where components may be present that may have particular sensitivity to such deposition or other processing operations. For example, one or more such optical sensors 1722 may be positioned to be located along the periphery of the sensor-mounted wafer, with the field of view 1723 oriented toward and proximate to a slit valve used to seal a wafer transport path through which the sensor-mounted wafer may pass when introduced into the semiconductor processing chamber 1750. Such a slit valve may be more susceptible to potential damage, e.g., from unwanted deposition or etching or from normal wear and tear. For example, such a slit valve may have an elastomeric seal that serves to seal the slit valve door to the semiconductor processing chamber 1750 to provide an airtight interface. Such a seal may be subject to wear each time the slit valve is opened or closed. If an optical sensor 1722, e.g., a sensor-mounted wafer with an image sensor, is provided as proposed, such optical sensor 1722 may be used to acquire data, e.g., one or more images, regarding the slit valve.Such data may allow the condition of the seal to be assessed without requiring the semiconductor processing chamber to be opened or the slit valve to be disassembled.

[0147] In some implementations, the sensor-mounted wafer may include one or more radially outward-facing optical sensors mounted on a support structure that is rotatably mounted relative to the substrate, an example of such a sensor-mounted wafer is shown in FIG. 18.

[0148] 18 shows a sensor-equipped wafer 1800 having a substrate 1802. The substrate 1802 has a support structure 1864 rotatably mounted relative to the substrate 1802. The substrate 1802 may also support a rotational drive 1866, e.g., a motor or other system, configured to cause the support structure 1864 to rotate relative to the substrate 1802 by at least a first amount of rotation. As shown, the rotational drive 1866 has a gear that engages gear teeth along the exterior of the support structure 1864, although alternative implementations may use a linkage-based mechanism (e.g., a crank arm coupled to a linear actuator), a friction drive mechanism (e.g., a wheel with an elastomeric outer rim compressed against the exterior of the support structure 1864), or the like. In some implementations, the first amount of rotation may be less than 360°, while in other implementations, the first amount of rotation may be 360° (or greater).

[0149] The one or more optical sensors 1822 may be supported by a support structure 1864 and oriented such that they have a field of view 1823 that faces radially outward from the center of rotation of the support structure 1864, for example. In some implementations, other electronics for the sensor-mounted wafer 1800, such as a controller, power supply, communication interface, etc., may also be mounted to the support structure 1864 such that all of the electronics rotate with the support structure 1864. In other implementations, however, at least some of the other electrical components of the sensor-mounted wafer 1800 may be mounted on the substrate 1802. In such implementations, the one or more optical sensors 1822 may be electrically connected, either directly or indirectly, to one or more of the electrical components mounted to the substrate 1802, for example, via a flexible cable. Alternatively, such electrical connection may be provided, for example, via a conductive path integrated into a bearing assembly used to rotatably support the support structure; for example, the electrical connection may be provided by a slip ring connection.

[0150] In such a sensor-equipped wafer, the controller can be controlled to cause one or more control signals to be provided to the rotational drive 1866. The control signals can cause the rotational drive 1866 to rotate, thereby causing the support structure 1864 (and the optical sensors 1822 attached thereto) to rotate relative to the substrate 1802. Through such rotation, the optical sensor(s) 1822 can be caused to shift between different rotational positions relative to the substrate 1802, thereby allowing data about regions of the interior wall(s) of the semiconductor processing chamber 1850 at different rotational positions to be collected using the optical sensor(s) 1822. In some implementations, such data can be continuously acquired from the optical sensor(s) 1822, and the support structure 1864 can be caused to rotate along with the optical sensor(s) 1822, effectively acting as a rotary scanner. In other implementations, the optical sensor(s) 1822 can be caused to acquire such data during rotation of the support structure 1864.

[0151] It will also be understood that a sensor-carrying wafer having a support structure configured to be rotatable relative to the substrate of the sensor-carrying wafer, e.g., as described above, can also be used with optical sensors having an upward-facing field of view, as in the case of the sensor-carrying wafer previously described with respect to FIG. 4. For example, the support structure may support one or more optical sensors having a field of view that faces upward, e.g., with a line of sight that is perpendicular or nearly perpendicular to the substrate. At least one of such optical sensors may be disposed at a radially offset distance from the axis of rotation of the support structure, such that the offset optical sensor(s) follow a circular path when the support structure is caused to rotate relative to the substrate. In such a system, the support structure may be caused to rotate to position the optical sensor(s) supported thereby below different locations on the underside of the showerhead, allowing optical data to be collected from different regions of the underside of the showerhead.

[0152] In another type of sensor-mounted wafer, the optical sensors may be located on a support structure that can be moved to reposition the optical sensors to locations that are at a greater distance from the center of the sensor-mounted wafer. Figures 19A and 19B show such a sensor-mounted wafer in two different operational states. As seen in Figure 19A, a sensor-mounted wafer 1900 is provided that includes a substrate 1902 and a support structure 1964 rotatably connected to the substrate 1902. The support structure 1964 is configured to be rotatable relative to the substrate 1902 about an axis located off-center of the substrate 1902, for example, about an axis located near an edge of the substrate 1902. Rotational drive 1966 is coupled to support structure 1964 such that when rotational drive 1966 is caused to rotate, support structure 1964 also rotates, which is shown in Figure 19B where rotational drive 1966 has been caused to rotate, thereby causing support structure 1964 to rotate by 180° relative to substrate 1902. Thus, support structure 1964 has rotated from a position in which it faces inward toward the center of substrate 1902 to a position in which it faces outward from substrate 1902.

[0153] The support structure 1964 may support one or more optical sensors 1922 having a field of view 1923, as shown. When the support structure 1964 is caused to rotate outboard of the substrate 1902 through actuation of the rotational drive 1966, this causes the optical sensors 1922 to be positioned at locations radially outward from the locations where such optical sensors 1922 were, for example, as shown in FIG. 19A . This may allow the sensor-mounted wafer 1900 to acquire optical data from components significantly larger than the footprint of the substrate 1902. For example, FIGS. 19A and 19B show the outline of the showerhead 1952 having a diameter much larger than the diameter of the sensor-mounted wafer 1900. The optical sensors 1922 may be repositioned to capture optical data of portions of the showerhead 1952 that are beyond the outer periphery of the substrate 1902, as shown in FIG. 19B . It will also be appreciated that such implementations may also allow the optical sensor to capture optical data from locations on the interior of the substrate 1902 that may in some cases not have any structure thereon. For example, if the substrate 1902 is annular in shape, i.e., has an opening in the center, such implementations would allow the optical sensor to be repositioned over the opening so that it can capture optical data of the area of the showerhead that is above the opening.

[0154] 19A and 19B may be implemented on a sensor-carrying wafer that shares some similarities with sensor-carrying wafer 700 of FIG. 7. FIG. 20 shows an example of such a sensor-carrying wafer. In FIG. 20, a sensor-carrying wafer 2000 is shown that includes support structures 2064a and 2064b. A first support structure 2064a is rotatably supported by a substrate 2002 (e.g., first support structure 2064a may be coupled to substrate 2002 via a rotational bearing), and a second support structure 2064b is rotatably supported by support structure 2064a. Thus, the first support structure 2064a can be caused to rotate relative to the substrate 2002 and about its central axis in response to a rotational input provided by the first rotational drive 2066a, and the second support structure 2064b can be caused to rotate relative to the first support structure 2064a about a rotational axis that is radially offset from the central axis of the substrate 2002 in response to a rotational input provided by the second rotational drive 2066b.

[0155] Such a configuration allows the second support structure 2064b to be rotated between different positions, thereby causing at least some of the optical sensors 2022 located on the second support structure 2064b to be moved between different radial positions relative to the center of the substrate 2002 (this is represented by the dotted outline of the second support structure 2064b and the optical sensors 2022 in FIG. 20). Additionally, the first support structure 2064a can be rotated (also shown by the dotted outline in FIG. 20) to cause the optical sensors 2022 located on the second support structure 2064b to rotate to different azimuthal positions relative to the substrate 2002. Such an implementation can be used, for example, to acquire optical data across the entire underside of a showerhead (represented by the dashed outline of the showerhead 2052 in FIG. 20) that is much larger than the footprint of the substrate 2002. For example, the first support structure 2064a may be caused to rotate relative to the substrate 2002, and the second support structure 2064b may be oriented to face inward toward the center of rotation of the first support structure 2064a. During such rotation, the optical sensor 2022, which may be an upward-looking imaging sensor, may be caused to periodically acquire optical data, e.g., images, of the underside of the showerhead above the substrate 2002 during such rotation. The second support structure 2064b may then be caused to rotate by 180° (or, more generally, between 90° and 180°) relative to the first support structure 2064a, so as to position at least some of the optical sensor 2022 out and position a portion of the second support structure 2064b on the substrate 2002. The first support structure 2064a may then be caused to rotate relative to the substrate 2002, with the second support structure 2064b in a partially out position. Further optical data may then be acquired periodically during such rotation from the optical sensor 2022 on the underside of the showerhead 2052, outside of the substrate 2002. The optical data collected during such rotation of the first support structure 2064a may then be combined together to form a composite data set representative of the entire underside of the showerhead 2052.Thus, such a sensor-equipped wafer may facilitate collecting optical data, e.g., image data, from a showerhead having a diameter larger (e.g., at least up to 25% or 50% larger) than the diameter of the substrate of such a sensor-equipped wafer.

[0156] As mentioned above, a sensor-mounted wafer can include multiple sets of different sensors, e.g., optical sensors, positioned to image different portions of a semiconductor processing chamber. Figures 21A-21E show diagrams of a sensor-mounted wafer with multiple different sets of optical sensors.

[0157] 21A and 21B show isometric views of the top and bottom, respectively, of a sensor-mounted wafer 2100. The sensor-mounted wafer 2100 may include a substrate 2102 that may support multiple different sets of optical sensors 2122, e.g., imaging sensors. For example, a first set of optical sensors 2122a may be disposed around the outer periphery of the substrate 2102 and oriented such that their fields of view 2123a (see FIG. 21C) are oriented radially outward from the central axis of the substrate 2102. Such optical sensors 2122a may be used to acquire optical data regarding visible characteristics of the interior walls of a semiconductor chamber in which the sensor-mounted wafer 2100 is to be used. A first set of illumination devices 2124a may optionally be provided adjacent to the optical sensors 2122a; for example, LEDs may be disposed on either side of each optical sensor 2122a and oriented to direct light radially outward. Such illumination devices 2124a may enable illumination of the surface(s) to be imaged.

[0158] A second set of optical sensors 2122b may be provided and distributed across the upper surface of the substrate 2102. The optical sensors 2122b may be oriented such that their fields of view 2123b (see FIG. 21D) are capable of acquiring optical data from a location directly above the sensor-equipped wafer 2100, e.g., the underside of the showerhead. A second set of illumination devices 2124b may also optionally be distributed across the substrate 2102 to direct light vertically upward, e.g., toward the showerhead, where it may be imaged using the optical sensors 2122b.

[0159] A third set of optical sensors 2122c may be provided and distributed across the upper surface of the substrate 2102, but with their fields of view 2123c (see FIG. 21E) directed vertically downward, for example, through apertures formed in the substrate 2102. Such optical sensors 2122c may be used, for example, to image locations below the sensor-carrying wafer, for example, the wafer pedestal. It will be appreciated that additional illumination sources for directing light vertically downward may also be provided, if desired.

[0160] Such a sensor-carrying wafer 2100 demonstrates the feasibility of mounting a sensor-carrying wafer with multiple different sensors arranged in different orientations and located in different regions to enable sensor coverage that can extend both above and below the sensor-carrying wafer, as well as around the center of the sensor-carrying wafer, thereby allowing data to be collected from almost any location within a semiconductor processing chamber or tool using the sensor-carrying wafer.

[0161] Another example of an exemplary semiconductor-carrying wafer is shown in FIGS. 22A-22C, which show an isometric view and two detailed views of a sensor-carrying wafer with steerable optical sensors. As seen in FIG. 22A, a sensor-carrying wafer 22A may be provided having a support structure 2264 rotatably supported relative to a substrate 2202. The support structure 2264 may be rotatably driven, for example, by a first rotational drive 2266a, such that the support structure 2264 may be caused to rotate about an axis perpendicular to the substrate 2202. The support structure 2264 may support an optical sensor 2222 mounted on a rotatable shaft, which may be caused to rotate about an axis parallel to the substrate 2202 by a second rotational drive 2266b. Such an arrangement may be used to allow the azimuth and elevation angles of the line of sight of the optical sensor 2222 to be adjusted to allow the optical sensor to be reoriented between any of several directions.

[0162] A sensor-mounted wafer according to the present disclosure may also or alternatively include other types of sensors. For example, in some implementations, a sensor-mounted wafer may include one or more ambient air sensors that, for example, measure one or more properties of the ambient atmosphere surrounding the sensor-mounted wafer. In the context of the present disclosure, ambient air sensors should be understood to be limited to gas concentration sensors configured to determine the concentration of at least a non-water gaseous component of the ambient atmosphere, e.g., a partial pressure sensor configured to measure the partial pressure of a non-water gaseous component in the ambient atmosphere, or airflow sensors configured to measure the velocity of gas flow past such airflow sensors. It will be further understood that ambient air sensors referred to herein may also refer to sensors configured to obtain water concentration measurements, e.g., the partial pressure of water, in addition to obtaining concentration measurements of at least one gas component other than water, e.g., the partial pressure of oxygen. Detection of gas concentrations of atmospheric constituents of ambient air (other than water) around a semiconductor processing tool may, for example, enable leak detection (as described in more detail below) to be performed using such gas concentration sensors. The presence of water in a semiconductor processing chamber is generally not a good metric for leak detection because there can be many factors that contribute to the presence of water in a semiconductor processing chamber other than atmospheric air leaking into the chamber.

[0163] In some implementations, the ambient air sensor(s) can be configured to obtain such measurements at ambient atmospheric conditions within a high-vacuum to rough-vacuum pressure range (e.g., 40 mTorr to 550 mTorr range, or lower), such as may be found within a semiconductor processing chamber during some semiconductor processing operations. One example of a sensor technology that can be used to obtain such measurements is an adsorption / desorption-based sensor technology, which is a substrate, such as a gallium nitride-based substrate, that selectively adsorbs a particular gas species, e.g., oxygen, and has an electrical property, such as resistance, that varies based on the amount of that gas adsorbed by the substrate. Such a substrate can also desorb that gas species when exposed to light, with the rate of gas desorption being proportional to the intensity of light to which the substrate is exposed, e.g., from an illumination source configured to illuminate the substrate. When the resistance across the substrate is at a steady state, this indicates that the rates of adsorption and desorption are in balance. Thus, by measuring the resistance through such a substrate and then adjusting the intensity of light emitted from an illumination source and directed toward the substrate until the resistance is equilibrated, it is possible to obtain a light intensity level corresponding to a state in which the adsorption and desorption rates are at equilibrium. This intensity level will be proportional to the partial pressure of the adsorbed gas and therefore the gas concentration, and can therefore serve as a measurement of the gas concentration. Such a sensor can be extremely compact, for example, fitting within a volume of, for example, 25 mm x 10 mm x 10 mm. Of course, other suitable sensor types can also be used for this purpose, and the present disclosure should not be considered limited to this particular exemplary type of gas concentration sensor. It will be understood that while the exemplary ambient air sensor described above integrates multiple different sensor types into a single integrated chip-based package, other implementations can use individual sensor devices, for example, each separately mounted to a substrate, to provide similar functionality.

[0164] One or more such ambient air sensors may, in some implementations, be included on a sensor-mounted wafer to provide a mobile platform that can be positioned at various locations within a semiconductor processing tool to assess atmospheric conditions at such locations, allowing, for example, atmospheric conditions within each semiconductor processing chamber of a multi-chamber semiconductor processing tool, as well as atmospheric conditions within, for example, a transfer chamber and / or load lock of the semiconductor processing tool, to be assessed.

[0165] In some implementations, such a sensor-mounted wafer may include multiple ambient air sensors disposed at different locations on the surface of the sensor-mounted wafer's substrate. Figure 23 shows an example of a sensor-mounted wafer 2300 having a substrate 2302 supporting multiple ambient air sensors 2332A-E, sometimes collectively referred to herein as ambient air sensors 2332. The sensor-mounted wafer 2300 is shown disposed on a pedestal 2362 within a semiconductor processing chamber 2350, and a slit valve 2368 is shown that can be moved up or down to seal or unseal a wafer transport passageway 2370 leading to the interior of the semiconductor processing chamber 2350. The ambient air sensors 2332 may be, for example, ambient air sensors configured to obtain partial pressure measurements of oxygen and water vapor in the ambient air surrounding each ambient air sensor 2332.

[0166] 23, when multiple ambient air sensors 2332 are utilized, such ambient air sensors 2332 may be disposed at spaced locations on the substrate 2302. For example, in FIG. 23, there are five ambient air sensors 2332, one located at the center of the substrate 2302 and others located at locations near the outer edge of the substrate 2302 and spaced 90° from each other. When multiple ambient air sensors are disposed at different locations, for example, as shown in FIG. 23, this allows partial pressure measurements of oxygen (and, optionally, water) to be taken simultaneously or near simultaneously at the different locations. Such measurements can then be used to a) obtain a more accurate assessment of whether ambient air conditions are within acceptable limits, for example, at more than a single location relative to the substrate 2302, and b) determine the direction in which a potential leak may be located.

[0167] Semiconductor processing chambers generally operate at sub-atmospheric conditions. Such chambers are typically machined from large blocks of metal, e.g., aluminum, to provide a sealed environment. Various openings and apertures in such components are sealed with vacuum-rated seals to prevent gas leakage from the external ambient environment, e.g., atmospheric air, into the interior of the semiconductor processing chamber. Such leaks can cause pressure increases and / or introduce contaminants (e.g., oxygen, etc.) that can adversely affect semiconductor processing operations performed within the semiconductor processing chamber. The concentration of such contaminants, and therefore the partial pressure resulting from those contaminants, is generally highest at the point(s) where such contaminants are introduced into the semiconductor processing chamber, i.e., at the location where the leak may exist, and then decreases with increasing distance from the leak point.

[0168] It should be noted, for clarity, that a "leak" in the context of the present disclosure should be understood to refer to a location in a semiconductor processing chamber where the amount of gas leaking from the ambient external atmosphere into the semiconductor processing chamber exceeds a predetermined threshold when the semiconductor processing chamber is at a specified sub-atmospheric pressure. A sensor-equipped wafer such as sensor-equipped wafer 2300 may be capable of determining, for example, when and where the level (e.g., concentration and / or partial pressure) of a particular component of the ambient atmospheric air, e.g., oxygen, exceeds a particular threshold.

[0169] In a sensor-mounted wafer such as sensor-mounted wafer 2300, partial pressure measurements of oxygen can be obtained using ambient air sensor 2332. Such measurements can then be used to determine an approximate direction relative to sensor-mounted wafer 2300 along which a leak location may be located. For example, FIG. 24 shows semiconductor processing chamber 2350 of FIG. 23, except that different partial pressure levels of a gas, e.g., oxygen, are indicated by different shaded regions separated by dashed lines. The partial pressure levels shown (P1-P5 represent decreasing pressures) represent partial pressure levels that would generally occur if there was a leak point, e.g., in the seal for slit valve 2368 at location A. Generally, an ambient air sensor measuring a partial pressure level, e.g., of oxygen, that is at a higher level compared to the partial pressure levels of such gas simultaneously measured by other ambient air sensors on sensor-mounted wafer 2300 will be physically closer to the leak that is the source of that gas than those other ambient air sensors. Generally, the more ambient air sensors 2332 that are distributed across or around the periphery of the sensor-carrying wafer, the more accurately the location of a leak can be determined using the sensor-carrying wafer 2300.

[0170] As can be seen, of the five ambient air sensors 2332, ambient air sensor 2332C will measure the highest partial pressure of oxygen at P1, and the next highest partial pressure of oxygen (just below P2) will be measured at ambient air sensor 2332B. Such information can be used to determine at least the sector of the sensor-on-wafer that is closest to a potential leak; for example, the location of such a leak can be determined to be generally within an α-degree circular sector 2334 of an arc extending outward from the center of the sensor-on-wafer 2300 and having a centerline 2336 passing through the ambient air sensor 2332 having the highest oxygen partial pressure reading (in this case, ambient air sensor 2332C). For a sensor-on-wafer 2300 with ambient air sensors evenly spaced around the periphery of the sensor-on-wafer 2300, angle α can be equal to 360° divided by the number of ambient air sensors 2332 located along the periphery of the sensor-on-wafer 2300. In the illustrated example, α is equal to 90°, and therefore the highest oxygen partial pressure reading at ambient air sensor 2332C indicates that the leak is radially outward from the rightmost quadrant (relative to the orientation of the figure) of sensor-mounted wafer 2300. Potential leak locations can, in some cases, be resolved with further granularity by considering data from other ambient air sensors 2332 on sensor-mounted wafer 2300. For example, two ambient air sensors 2332B and 2332A are measuring partial pressure readings in this example that are just below P2 for ambient air sensor 2332B and approximately P3 for ambient air sensor 2332A. In contrast, ambient air sensor 2332D indicates a partial pressure reading that is less than P4. Thus, an increase in the partial pressure reading of ambient air sensor 2332B compared to the lower partial pressure reading of ambient air sensor 2332D indicates that leak location "A" is on the side of centerline 2336 closer to ambient air sensor 2332B, thereby allowing leak location "A" to be further narrowed from the octant of sensor-mounted wafer 2300 above centerline 2336 (relative to the orientation of the figure) to a location radially outward.

[0171] Generally, a good approximation of where one or more potential leaks may exist can be determined by identifying, for example, a local peak in the partial pressure readings where an ambient air sensor 2332 reports a higher partial pressure reading than the partial pressure reading reported by a circumferentially adjacent ambient air sensor 2332. This can indicate that a leak exists generally at a location along an axis between a radius extending radially outward from the sensor-containing wafer and a radius extending outward from the wafer center, and midway between the ambient air sensor 2332 reporting the local peak and the circumferentially adjacent ambient air sensor 2332. The location of the leak can be further refined, for example, to one side or the other of the ambient air sensor 2332 reporting the local peak partial pressure, based on which of the ambient air sensors 2332 circumferentially adjacent to the ambient air sensor 2332 reporting the local peak partial pressure reports the higher partial pressure.

[0172] While the above examples employed ambient air sensors that measure the partial pressure of oxygen, it will be understood that similar techniques can be practiced using partial pressure sensors that measure the partial pressure of other gases that may be present in ambient atmospheric air, such as nitrogen (N), argon (Ar), carbon dioxide (CO), and neon (Ne). It will also be understood that other types of gas concentration sensors (other than partial pressure sensors) can be used in place of or in addition to the partial pressure sensors described above. It will also be understood that during such measurements, the gas whose partial pressure is being sought may in some cases be prevented from flowing into the semiconductor processing chamber; for example, if the semiconductor processing tool is configured to supply oxygen gas to the semiconductor processing chamber during some stages of normal semiconductor processing operation, such deliberate oxygen delivery during leak testing may be prevented; therefore, the only potential source of oxygen (or other gases detectable by the ambient air sensor) is a leak at one or more locations within the semiconductor processing chamber.

[0173] Such semiconductor processing chambers may also include an exhaust system that can be used to evacuate process gases introduced during semiconductor processing operations and maintain a desired vacuum level within the semiconductor processing chamber. During leak testing, it may also be desirable to temporarily deactivate such exhaust systems to avoid affecting the partial pressure levels of contaminants within the semiconductor processing chamber. Thus, for example, the gas concentration measurements described above may be performed within the semiconductor processing chamber using the sensor-mounted wafer 2300 (or the like), but the interior atmosphere of the semiconductor processing chamber is not perturbed by incoming (except for potential leaks, of course) or outgoing gas flows, movement of components within the interior of the semiconductor processing chamber (e.g., changes in the height of the pedestal and / or showerhead), opening and / or closing of valves and / or doors, or activation of systems such as turbopumps or cryopumps. By performing such measurements in the “motionless” interior ambient atmosphere, potential sources of partial pressure fluctuations other than potential leak points are minimized or eliminated, thereby increasing the likelihood of accurately detecting such leaks and identifying where such leaks may be located.

[0174] It will be further appreciated that some implementations of the sensor-equipped wafer may employ gas concentration sensors that may be configured to obtain readings of gases other than those typically found in atmospheric air, e.g., gases that may be used in semiconductor processing operations, may be by-products of such processing operations, and / or may be introduced into the processing chamber from other locations within the tool, e.g., from other processing chambers within the tool (e.g., may accompany a wafer being transferred to the chamber from another chamber within the tool). For example, in some implementations, the sensor-equipped wafer ... such as hydrogen species (H x ), ozone (O3), nitrogen oxide (NO xThe system may employ one or more gas concentration sensors configured to detect concentrations of carbon monoxide (CO₄), chlorofluorocarbons (CFCs), methane (CH₄), and / or volatile organic compounds (VOCs). Such species may, for example, outgas from materials deposited on wafers in the processing chamber. Such materials may also deposit on surfaces of the processing chamber and thus remain in the processing chamber even after one or more wafers being processed are removed. Materials remaining in the processing chamber after wafer removal may, for example, outgas or react with other gases in the processing chamber to create gas species that, if their concentration exceeds a certain threshold, may be deemed sufficiently harmful to processing operations to be performed in such processing chambers to warrant taking corrective action, e.g., subjecting the chamber to a cleaning process or removing the chamber from the tool and replacing it with a new one.

[0175] In some implementations, the sensor-mounted wafer may include a particulate sensor, such as, for example, an ionization or photoelectric particulate sensor (similar to, but potentially more sensitive than, sensors used in smoke detectors to detect smoke particulates). In an ionization detector, a small sample of radioactive material that ionizes or charges gas molecules in the atmosphere being sensed is provided between two metal plates, e.g., electrodes, in a sample chamber that is in fluid communication with the atmosphere being monitored. As solid particles, e.g., particulates, flow through the chamber, they attract the ionized species and carry them away, thereby reducing the current flowing between the two electrodes. The reduction in the amount of current provides a measure of the amount of particulates that may be present. In a photoelectric particulate detector, the light source may be configured to direct the light beam so that it passes by a photodetector associated with the light source without impinging on it, e.g., so that the light beam traverses in front of and parallel to, but does not impinge on, the photosensitive surface of the photodetector. However, when particulates are present in the atmosphere in front of the photodetector, some of the light rays that would normally pass by the photodetector instead hit the particulates and are scattered from them, which results in some scattered light hitting the photodetector. The amount of such light that hits the photodetector provides a measure of the concentration of particulates in the atmosphere.

[0176] A sensor-mounted wafer with one or more particulate sensors can be used to detect the presence of particulate contaminants within a semiconductor processing chamber. Such particulates can arise, for example, from moving components within the processing chamber, such as mechanical wear between lift pins and / or pedestals moving up and down, wafer handling robot movement within the chamber, showerhead movement within the chamber, etc., or can be by-products of semiconductor processing operations, such as deposited material that may have accumulated on surfaces of the semiconductor processing chamber and may have been detached from such surfaces, for example, by flaking.

[0177] For example, it will be appreciated that techniques similar to those described above for sensor-mounted wafers with atmospheric gas concentration sensors for leak detection can also be used with gas concentration sensors configured to detect gas species not normally found in atmospheric air, but for a slightly different purpose. In leak detection, the gas being detected originates in the processing chamber via a leak path from the ambient atmosphere around the tool. In sensor-mounted wafers with gas concentration sensors configured to detect gases other than those found in atmospheric air, the gas being detected may originate in the processing chamber through outgassing or other mechanisms. Thus, a technique for detecting potential locations of leak points using a gas concentration sensor configured to detect oxygen can similarly be used with a gas concentration sensor configured to detect, for example, CFCs outgassed from deposited films in the processing chamber. Instead of indicating potential leak detection points, such techniques can instead indicate one or more areas of the chamber where such deposited films are present in the greatest concentrations. Similarly, such techniques can also be implemented with particulate sensors to similar effect, for example, to detect one or more areas of the processing chamber producing the greatest concentrations of particulates.

[0178] Some implementations of a sensor-mounted wafer may have one or more gas concentration sensors and / or one or more particulate sensors (potentially in addition to other sensors described herein). In some implementations, such a sensor-mounted wafer may include multiple gas concentration sensors configured to detect the same type of gas (e.g., to facilitate determining the location of a leak or the location of an area of the chamber that produces the greatest amount of outgassing). In some other or additional such implementations, gas concentration sensors or sets of gas concentration sensors for detecting different types of gas may be located on a common sensor-mounted wafer. For example, a sensor-mounted wafer may have one set of gas concentration sensors for detecting oxygen (for leak detection) and another set of gas concentration sensors for detecting CFCs (for detecting the location of outgassing from deposition byproducts on chamber surfaces).

[0179] In semiconductor processing tools in which such sensor-equipped wafers may be used, a controller of the semiconductor processing tool may be configured to move such sensor-equipped wafers between different locations, for example, between a storage or loading location and a semiconductor processing chamber of the semiconductor processing tool. The semiconductor processing tool controller may further be configured to send one or more commands to the sensor-equipped wafer, for example, via a wireless communication link, to cause the sensor-equipped wafer's controller to obtain one or more sensor readings via its ambient air sensors. For example, a concentration or partial pressure measurement of a particular component, e.g., oxygen, of a gas within the semiconductor processing chamber and surrounding the sensor-equipped wafer may be caused to be obtained. The semiconductor processing tool controller may also cause various other actions to be performed prior to causing such measurements to be obtained.

[0180] Figure 25 illustrates an exemplary semiconductor processing tool (or portion thereof) that may be configured to utilize sensor-equipped wafers similar to those described above with respect to Figures 23 and 24. As seen in Figure 25, a semiconductor processing tool 2548 is shown having a vacuum transfer module 2580 to which six semiconductor processing chambers 2552 are connected. A wafer handling robot 2554 may be located within the vacuum transfer module 2580 and may be configured to be able to move wafers between the various semiconductor processing chambers 2552 (e.g., a load lock that may be used to transfer wafers to and from the vacuum transfer module 2580, e.g., from the EFEM, is not shown).

[0181] Each semiconductor processing chamber 2552 may have a pedestal 2562 and a showerhead 2553 located within the pedestal. The pedestal may be configured to flow gases provided by one or more gas sources 2576 when one or more valves (represented by a symbol of two triangles joined end-to-end) controlled by a controller 2574 are caused to open, e.g., during semiconductor processing operations. Each semiconductor processing chamber 2552 also includes a door 2568 that may be controlled by the controller 2574 to transition between an open state and a closed state, thereby allowing the semiconductor processing chamber 2552 to be sealed and unsealed, e.g., during wafer processing operations, to allow wafers to be passed to or from the semiconductor processing chamber 2552. The semiconductor processing tool 2548 may also have or be connected to a vacuum pump 2578 that may be fluidly connected to each semiconductor processing chamber 2552 to be able to evacuate processing gases from the semiconductor processing chamber 2552. The exhaust flow from each semiconductor processing chamber 2552 can be adjusted by a corresponding valve controlled by the controller 2574, for example, to allow the exhaust for each semiconductor processing chamber 2552 to be throttled up or down or even stopped completely as needed.

[0182] As can be seen, the controller 2574 can be caused, for example, via computer-executable instructions stored on a memory device, to control the wafer handling robot 2554 to place the sensor-equipped wafer 2500 in one of the semiconductor processing chambers 2552 (in this case, as shown in the top-left semiconductor processing chamber 2552). The controller 2574 can then cause the wafer handling robot 2554 to withdraw from the semiconductor processing chambers 2552, leaving the sensor-equipped wafer 2500 in place on the pedestal 2562, as shown in dashed outline in the center-left semiconductor processing chamber 2552. When the wafer handling robot 2554 is withdrawn from the semiconductor processing chamber 2552, the controller 2574 may cause the flow of gas from one or more gas sources 2576 to that semiconductor processing chamber 2552 to stop, for example, by controlling one or more valves to transition to a closed state, and may cause the chamber door 2568 to transition to a sealed state (illustrated in the left-center semiconductor processing chamber 2552 by the door 2568 for that chamber being shaded black). The controller 2574 may then send one or more commands to the sensor-mounted wafer 2500 to cause the sensor-mounted wafer 2500 to obtain one or more sensor readings from one or more ambient air sensors located thereon (indicated by five small squares on the sensor-mounted wafer 2500). Data from the sensor readings may then be stored, for example, in memory on the sensor-mounted wafer and / or transmitted to the controller 2574 for further processing.

[0183] The controller 2574 and / or the controller of the sensor-equipped wafer may determine, for example, a) whether there is a potential leak (based on the peak concentration or partial pressure of a particular component of the ambient atmospheric air in the semiconductor processing chamber, e.g., oxygen, exceeding a predetermined threshold level) and, in some cases, b) the potential location(s) of such leak(s), as described above.

[0184] In some alternative or additional implementations, the ambient air sensor(s) used may include an ambient air sensor configured to obtain measurements at non-vacuum ambient atmospheric conditions, e.g., at or near 1 atmosphere pressure, such as may be found in an equipment front-end module (EFEM), a front-opening unified pod (FOUP), or other equipment that stores semiconductor wafers either within a semiconductor processing tool or during transport between semiconductor processing tools or other equipment.

[0185] In such implementations, the ambient air sensors used may include one or more different types of sensors, including, but not limited to, relative humidity sensors, oxygen level sensors, temperature sensors, and airflow sensors (e.g., anemometers). A sensor-mounted wafer loaded with one or more such sensors may be used, for example, to evaluate and / or characterize different aspects of equipment operating in atmospheric conditions. For example, while the atmosphere within an EFEM is generally kept at or near atmospheric pressure levels, the atmosphere within such an EFEM may, in some cases, be pre-treated to have a specified humidity level and / or temperature. In some cases, an EFEM may have an atmosphere that is significantly different in composition from ambient atmospheric air; for example, an EFEM may be supplied with an atmosphere from which most or all oxygen has been removed and / or in which nitrogen is present, either exclusively or at a concentration much greater than that of nitrogen in atmospheric air.

[0186] Ambient air sensors measuring humidity, temperature, and / or gas concentrations may therefore be used to assess what the actual humidity levels, temperature levels, and / or gas concentrations within such an EFEM may be. Such measurements may then be compared to target values to determine whether the EFEM has a desired internal environment. It will be appreciated that such measurements may be obtained by such sensor-equipped wafers in other environments as well, e.g., within a wafer storage buffer, within a FOUP, within a wafer cassette, etc.

[0187] As mentioned above, some sensor-mounted wafers may be equipped with one or more airflow sensors to allow measurements of the velocity of air (or other gas or gas mixture) across the sensor-mounted wafer to be obtained. Such measurements may allow assessments to be made, for example, regarding the effectiveness of various airflow systems within an EFEM, FOUP, buffer, or other system ("airflow" being understood to include systems that may operate with gases other than air, e.g., nitrogen). For example, in some buffers and / or FOUPs, an inert gas such as nitrogen may be introduced into and then exhausted from such structures in a manner that causes a certain minimal amount of gas flow to occur over each wafer that may be placed in such structures. For example, a buffer may employ a set of 25 shelves arranged in a vertical stack with 10 mm spacing between each pair of shelves. Each shelf may be used to temporarily support a wafer while that wafer occupies the buffer. The buffer may have a gas inlet that directs an inert gas such as nitrogen into the buffer, so that at least a portion of the inert gas flows over the top of each wafer loaded into the buffer (when the buffer is full). In such a buffer, it may be desirable to have a specified minimum level of inert gas flow above each wafer, regardless of which position it is in. Sensor-equipped wafers equipped with airflow sensors, as described above, may be placed at different wafer positions within such a buffer, and the airflow sensors may be used to obtain direct measurements of the amount of gas flow occurring above wafers that may be placed at each of those positions.

[0188] Such airflow sensors may include, for example, anemometers, e.g., hot wire anemometers. Such sensors are available in small form factors suitable for use on sensor-mounted wafers. For example, low-profile surface-mount microelectromechanical systems (MEMS)-based air velocity sensors having a thickness of only a few millimeters, e.g., 4 millimeters or less, may be used. Such sensors may operate like hot wire anemometers, with air flowing past a wire carrying an electric current. As the air cools the wire, this changes the resistance of the wire in a manner corresponding to the airflow velocity passing by it. Such sensors are suitable for use on sensor-mounted wafers, which may need to maintain an overall maximum thickness of 5 mm or less, for example, to be transportable within a semiconductor processing tool without violating clearance requirements for semiconductor wafers.

[0189] Figure 26 shows a schematic diagram of a portion of a semiconductor processing tool. In Figure 26, an EFEM 2684 is shown. The EFEM 2684 may have multiple load ports 2686 connected thereto, each of which may receive a FOUP 2688 that contains or may receive wafers to be or have been processed in the semiconductor processing tool. The EFEM 2684 may have a wafer handling robot 2654 located therein that is configured to move wafers between the FOUP 2688, the load lock 2692, and / or the buffer 2682. A controller 2674 may control the wafer handling robot 2654 and various other systems of the EFEM 2684, such as the FOUP door, the load lock door, etc.

[0190] Buffer 2682 may have multiple wafer storage locations arranged in a stacked configuration, for example (as shown in the side view of buffer 2682 shown in the upper left corner of FIG. 26.) In some cases, buffer 2682 may have a pressurized plenum that introduces a gas, e.g., nitrogen, or other gas that is non-reactive, into the buffer with wafers loaded therein, so that the gas then flows over the wafers stored therein, for example, along the path indicated by the arrows in buffer 2682.

[0191] A controller 2674 in such a semiconductor processing tool may cause the wafer handling robot 2654 to move the sensor-mounted wafer 2600 between various locations 2690 and send one or more commands to the sensor-mounted wafer 2600 to cause the sensor-mounted wafer 2600 to obtain sensor readings, e.g., airflow readings, from one or more ambient air sensors located thereon while the sensor-mounted wafer 2600 is at each location 2690. Such readings may be stored in the sensor-mounted wafer, e.g., in memory located on the sensor-mounted wafer, or transmitted to the controller 2674.

[0192] In some implementations, the sensor-mounted wafer may include one or more sound sensors (e.g., audio sensors or microphones) that can be used to collect audio data from both the surrounding environment or the sensor-mounted wafer itself. In some embodiments, the one or more sound sensors may include a capacitive microphone, a peak detector, and an amplifier. For example, if a wafer-handling robot transferring a sensor-mounted wafer with one or more microphones has bearings that begin to deteriorate, this may cause small vibrations in the end effector of the wafer-handling robot, which are then transmitted to the sensor-mounted wafer. Such vibrations can generate audible noise artifacts that are transmitted through the structure of the sensor-carrying wafer itself, i.e., acoustic signals that can have a characteristic frequency spectrum and / or signal strength; for example, the sensor-carrying wafer can vibrate such that a portion of it repeatedly lifts off and then drops back down onto the support feature of the end effector, resulting in a series of high-speed contact events between the sensor-carrying wafer and the support feature, each contact event generating an acoustic pulse that is transmitted through the structure of the sensor-carrying wafer and then detected by a microphone(s) attached thereto. Such acoustic signals can have frequencies, for example, in the range of 20 Hz to 20,000 Hz.

[0193] Such microphone-equipped wafers can also be used to detect acoustic events that result in sound waves reaching the microphones via atmospheric transmission (as opposed to via acoustic propagation through solid materials). For example, equipment beginning to fail or experiencing excessive wear may produce sounds that are detectable by such microphone-equipped wafers, enabling potential detection of such problems within a processing chamber or vacuum transfer chamber. In some sensor-equipped wafers, multiple microphones may be used, placed at different locations, similar to the gas concentration sensor placement described with respect to FIG. 23, to enable the location of the source of a detected acoustic event relative to the sensor-equipped wafer to be determined, similar to how leaks can be detected using gas concentration sensors. This may allow, for example, a sensor-equipped wafer with microphones to be used not only to detect acoustic events that may indicate potential component failure, but also to determine the general location of where those acoustic events occurred, which may help identify which component is the source of the acoustic event (and therefore which may require replacement or service).

[0194] Generally, acoustic data from a microphone sensor will provide time-domain data indicative of acoustic signal strength at any given moment in time. However, such acoustic data may represent multiple different sources of acoustic signals that are combined with each other and simultaneously received by the microphone sensor as a single blended acoustic signal. Such acoustic data may be subjected to various types of post-processing, for example, to provide data better suited to various analysis techniques.

[0195] For example, analog signals from microphone sensors may be converted to digital representations using analog-to-digital conversion. Digitized data from successive time intervals may then be processed using a fast Fourier transform to obtain frequency-domain data, from which a power spectral density over the time interval may be determined. The power spectral density provides information related to signal strength at different frequency bins. Such information may be used in both characterizing potential sources of such acoustic signals and determining potential locations of the acoustic signals, as described below.

[0196] Figure 27 shows an example of a sensor-mounted wafer 2700 that includes multiple microphone sensors 2738, e.g., microphone sensors 2738A-E. The sensor-mounted wafer 2700 is shown in Figure 27 mounted on a pedestal 2762 within a chamber 2750. The chamber 2750 may include a wafer transport pathway 2770 through which the sensor-mounted wafer 2700 may be inserted into or removed from the chamber 2750.

[0197] The microphone sensors 2738A-E are, in this example, omnidirectional microphone sensors arranged in a distributed manner across the substrate 2702. As shown, the microphone sensors 2738A-E are arranged in a cross pattern, with one microphone sensor 2738A located in the center of the substrate 2702 and the four remaining microphone sensors 2738B-E arranged in a circular, evenly spaced array at the edges of the substrate 2702. It will be understood that more or fewer microphone sensors 2738 may be used, and that, for example, as few as three microphone sensors 2738 may be used to determine the direction from which a particular sound is coming via triangulation based on the timing of when the same acoustic signal is detected by each individual microphone sensor 2738 and / or via trilateration based on the signal strength measured by each microphone sensor in response to the same acoustic event. In either case, the signal detected by each microphone sensor may be used as an analog for the distance between the source of the acoustic event being detected and that microphone sensor.

[0198] In trilateration, the strength or signal intensity of the acoustic signal detected by each microphone sensor can serve as an indication of the distance between each microphone sensor and the source of the acoustic event. In triangulation, the timing difference between receipt of the same acoustic signal by the microphone sensors can serve as an indication of the relative distance from each microphone sensor to the source of the acoustic event. In triangulation, the distance analog can take the form of a scalable component (represented by the timing difference between receipt of the acoustic event signal between the microphone sensors) added to a constant component (which will be the same for all signals and represents the shortest distance between any of the microphone sensors and the source of the acoustic event, i.e., the distance between the acoustic event source and its nearest microphone sensor). It will be appreciated that in either triangulation or trilateration, the signal being evaluated (in terms of either signal strength or timing of receipt) may actually be a sub-portion of the acoustic signal, e.g., a sub-signal in a particular frequency range. For example, after transforming the acoustic signal into the frequency domain via a Fast Fourier Transform, analysis may show that the frequency bin with the highest signal strength contribution to the overall signal is the 190 Hz-200 Hz frequency bin. In triangulation and / or trilateration techniques, the timing of reception and / or signal strength obtained and evaluated in each such technique may be determined based on the timing of reception or signal strength of the acoustic signal component in the 190 Hz-200 Hz frequency bin.

[0199] Each distance analog can be treated as defining the radius of a circle centered on the corresponding microphone sensor. In the ideal case, where the distance analogs are scaled to match the actual distance between the corresponding microphone sensor and the source of the acoustic event, the circles would all pass through the point corresponding to the source of the acoustic event (or, taking potential measurement errors into account, would pass through a circular area centered on such a point, the size of which can be selected to correspond to a desired level of location determination accuracy). Since the positions of the microphone sensors on the substrate relative to one another are known, the location of the acoustic event relative to the substrate can be determined by adjusting the scaling of the distance analog until a solution can be found for a point (or circular area) where some number or all of the above circles intersect, with the point of intersection representing the location of the source relative to the substrate. If the location and orientation of the substrate relative to the process chamber are known, this allows the location of the acoustic event relative to the chamber to be determined.

[0200] Scaling the range analog may involve simply scaling the range analog (in the case of trilateration) or scaling a scalable component of the range analog and varying a constant component of the range analog (in the case of triangulation).

[0201] The concepts described above are represented in Figure 27 by the overlay of three dotted circles 2742A, 2742B, and 2742C centered on three microphone sensors 2738A, 2738B, and 2738C. Similar circles are not shown for microphone sensors 2748D and 2738E, although such circles could be added if desired. Also shown in Figure 27 are acoustic signals 2740A, 2740B, and 2740C detected by microphone sensors 2738A, 2738B, and 2738C over the same time interval in response to an acoustic event occurring at acoustic event location 2744 (time is along the x-axis and signal strength is along the y-axis). Acoustic signals 2740A, 2740B, and 2740C can be seen to have different maximum signal strengths, as evidenced by the horizontal dotted lines coinciding with the peaks of acoustic signals 2740A, 2740B, and 2740C.

[0202] Circles 2742A, 2742B, and 2742C are shown with radii proportional to the corresponding signal strengths of acoustic signals 2740A, 2740B, and 2740C. Circles 2742A, 2742B, and 2742C have been scaled in this case to all intersect at a common point, i.e., location 2744. Thus, the radii of circles 2742A, 2742B, and 2742C represent the actual distance between each of microphone sensors 2738A, 2738B, and 2738C and location 2744. By solving for the location where all three circles 2742A, 2742B, and 2742C intersect, the position of location 2744 relative to substrate 2702 can be determined, which may allow for subsequent determination of where location 2744 is located relative to chamber 2750.

[0203] Additional microphone sensors 2738 other than three such microphone sensors 2738 may provide additional acoustic signal data, which may be used to further refine the signal direction determination performed using the data collected by such microphone sensors 2738.

[0204] FIG. 28 illustrates another example of a sensor-mounted wafer 2800. The sensor-mounted wafer 2800 can include a substrate 2802 supporting a plurality of microphone sensors 2838, which in this example are directional microphone sensors. Such microphone sensors 2838 can have a directional bias in their sensitivity, e.g., sensitivity to azimuthally varying acoustic signals. In FIG. 28, pickup zones 2846 are shown representing the relative sensitivity for each microphone sensor 2838 as a function of the azimuth direction relative to the microphone sensor 2838. The farther any portion of the dotted line representing the pickup zone 2846 is from the corresponding microphone sensor 2838, the more sensitive the microphone sensor 2838 is to acoustic signals originating along a line extending from the microphone sensor 2838 to that portion of the dotted line.

[0205] 28 , the microphone sensors 2838 are arranged in an evenly spaced circular array around the periphery of the substrate 2802. Such an arrangement may enable rapid determination of the azimuthal direction along which the acoustic event occurred, for example, by identifying two or three such microphone sensors 2838 that detect the highest strength signal resulting from the acoustic event. For example, if one microphone sensor detects the highest strength signal resulting from the acoustic event and two microphone sensors near that sensor detect acoustic signals of equal signal strength, it may be assumed that the acoustic event occurred at a location along a radius extending outward from the center of the substrate 2802 and through the microphone sensor 2838 that detected the highest strength signal. If two nearby microphone sensors 2838 are not equal in size, the microphone sensor 2838 of the two nearby microphone sensors 2838 that detected the acoustic signal with the second-highest signal strength may be used, along with the highest strength acoustic signal, to determine a ratio that may be applied to the angular spacing between the microphone sensors 2838 to determine from which direction the acoustic signal appears to have originated.

[0206] For example, in the illustrated example, the angular spacing between the microphone sensors 2838 is 45°. If the microphone sensor 2838 at the 12 o'clock position detects the highest strength signal (S1) of the acoustic event and the microphone sensor 2838 to its right detects the second-highest strength signal (S2) of the acoustic event, the azimuthal direction relative to the center of the substrate 2802 along which the acoustic event location lies can be determined to be between the two microphone sensors 2838 that recorded their highest signal strengths from the acoustic event and angularly offset by angle θ from a first radius extending from the center of the substrate 2802 to the center of the microphone sensor that detected the highest signal strength acoustic signal. The angle θ can be determined by multiplying the angle defined between the first radius and a second radius extending from the center of the substrate 2802 to the center of the microphone sensor that detected the second-highest signal strength acoustic signal by S1 / (S1+S2).

[0207] Such a determination can be used to identify the azimuthal angle relative to the substrate 2802 along which the acoustic event occurred. A further determination can be made regarding the relative orientation of the substrate 2802 with respect to the chamber to determine the direction relative to the chamber along which the acoustic event occurred.

[0208] FIG. 29 illustrates another exemplary sensor-carrying wafer in the context of a processing chamber. As shown in FIG. 29 , a sensor-carrying wafer 2900 is supported on a pedestal 2952 of a chamber 2950. The sensor-carrying wafer 2900 includes a substrate 2802 that rotatably supports a support structure 2964. The support structure 2964 can be caused to rotate, for example, by a rotational drive 2966. The support structure 2964 can support a microphone sensor 2938, which can be a directional microphone similar to the previously described directional microphone sensor 2838. A dotted line 2946 indicates the pickup zone for the microphone sensor 2938. 29, the microphone sensor 2938 can be caused to rotate about the center of rotation of the support structure 2964, thereby reorienting the pickup zone such that the axis of maximum sensitivity of the microphone sensor can be changed to any desired angle. This allows the microphone sensor 2938 to be used to scan azimuthally around the circumference of the substrate 2902 for audio signals.

[0209] For example, the support structure 2964 may be caused to rotate through a number of different angular positions, and data from the microphone sensor 2938 may be collected at each such angular position. If such a rotational scan is performed while an acoustic event is occurring, the angular position at which the highest acoustic signal strength for that acoustic event is detected will generally indicate the direction along which the acoustic event is occurring. For example, a radius extending from the center of rotation of the support structure 2964 through the microphone sensor 2938 may be aligned with the origin of the acoustic event when the support structure 2964 is oriented so that the acoustic signal detected by the microphone sensor 2938 is at a maximum.

[0210] In the techniques described above, in which microphone sensors are used to directionally locate the origin of an acoustic signal, it may be necessary to obtain such sound measurements while the chamber in which the measurements are being taken is held at an air pressure sufficient to transmit sound waves without experiencing undesirable acoustic signal attenuation. Thus, for example, the process chamber (or other chamber) in which such measurements are to be taken may be controlled to cause a gas, e.g., a chemically inert or non-reactive gas such as argon or nitrogen, to flow into the chamber to provide a sound propagation medium.

[0211] In some implementations, a sensor-mounted wafer with one or more microphone sensors can be used to determine the origin of an acoustic event, for example, using acoustic fingerprinting techniques. For example, as described above, acoustic data collected by the microphone sensors can be analyzed to obtain a power spectral density of the acoustic signal. Such power spectral density data can be provided to a machine learning algorithm, which classifies the obtained power spectral density into one of several potential acoustic event types or sources based on characteristics of the power spectral density data. For example, a particular acoustic signal, after being transformed into the frequency domain and analyzed to obtain a power spectral density, may exhibit characteristics that align with an acoustic fingerprint in which the three highest signal intensities occur within frequency bands of 100 Hz, 120 Hz, and 200 Hz (each ±5 Hz), and the signal intensities of the 120 Hz and 200 Hz frequency components are 50% ±20% of the signal intensity of the 100 Hz frequency component.

[0212] Such machine learning algorithms may be trained using acoustic signal data acquired by such sensor-mounted wafers under conditions that generate acoustic events due to, for example, known errors or operating conditions. For example, such machine learning algorithms, e.g., neural nets, may be trained using datasets of acoustic signal data acquired by sensor-mounted wafers having microphone sensors while they are being transported by one or more wafer-handling robots known to produce acoustic events caused by, for example, rotating bearings nearing the end of their useful life. Different datasets of acoustic signal data resulting from different potential acoustic signal sources (error conditions) may be provided to the machine learning algorithm to train the algorithm to recognize various different acoustic signal types, with each acoustic signal type serving as a fingerprint for the particular error condition that generates that acoustic signal type. When a particular potential source / error condition associated with a particular acoustic fingerprint is identified, a notification may be generated to notify an operator of the potential error condition.

[0213] Acoustic fingerprinting techniques such as those described above may allow the location of a particular acoustic event to be determined without necessarily having to rely on multiple microphone sensors or movable microphone sensors, for example, if the acoustic fingerprint is associated with a particular component in a semiconductor processing tool. This allows the sensor-mounted wafer to collect acoustic signal data, for example, under vacuum conditions, and still identify where the acoustic event is likely occurring. For example, an acoustic signal may be provided to the sensor-mounted wafer 2900 through acoustic coupling through a solid structure, for example, through the structure of the wafer handling robot itself. By analyzing the received acoustic signal and matching the frequency component strengths therein to the acoustic fingerprint, the source of the acoustic signal (the component of the semiconductor processing tool generating the signal) may potentially be identified, thereby identifying where the acoustic signal originated from.

[0214] Because the sensor-onboard wafers described herein are self-powered, e.g., have a battery or other power source, and are configured to be capable of communicating with one or more other devices, e.g., via a wireless connection, such sensor-onboard wafers can provide a highly flexible architecture for collecting measurements that can be used to qualify, evaluate, characterize, and / or quantify various aspects of semiconductor tool performance. For example, in some implementations, such a sensor-onboard wafer can be configured to receive commands indicating that one or more measurements should be taken from one or more sensors of the sensor-onboard wafer. A controller that is separate from the sensor-onboard wafer, e.g., a tool controller that may control various systems of a semiconductor processing tool, can be configured to establish a communications link with the sensor-onboard wafer and then periodically send instructions to the sensor-onboard wafer to cause the sensor-onboard wafer to acquire a desired set of measurements. For example, the controller may be provided with computer-executable instructions that cause the controller to cause a wafer-handling robot of the semiconductor processing tool to retrieve a sensor-equipped wafer, for example, from a dedicated storage alcove in the EFEM or from a FOUP in which the sensor-equipped wafer is stored, and move it to one or more locations within the EFEM (and / or buffer and / or FOUP(s)). Such instructions may also cause the controller to send instructions to the sensor-equipped wafer while moving it from location to location that cause the sensor-equipped wafer to take one or more measurements using one or more of the sensors in the sensor-equipped wafer at each such location.

[0215] Measurement data collected by such a sensor-equipped wafer may, in some cases, be stored in one or more memory devices on the sensor-equipped wafer and later retrieved. In other or additional cases, such measurement data may be transmitted in real time or near real time using a wireless interface of the sensor-equipped wafer (if present) to an external device, such as a controller of a semiconductor processing tool in which the sensor-equipped wafer is being used. If the sensor-equipped wafer includes additional sensors, such as a relative humidity sensor, a temperature sensor, etc., the acquired sensor readings may include measurement data from such additional sensors as well.

[0216] In some implementations, the sensor-equipped wafer may include both an airflow sensor and a gas concentration and / or partial pressure sensor for use in atmospheric or near-atmospheric conditions. For example, some EFEMs may be configured to have an internal atmosphere within the EFEM that has a different gas composition than that found in ambient atmospheric air. For example, such an EFEM may be configured to maintain an atmosphere of pure nitrogen (or at least an atmosphere free of oxygen). In practice, maintaining such an environment is not possible because EFEMs are generally not hermetically sealed (unlike semiconductor processing chambers, which are sealed so that they can be maintained at sub-atmospheric pressures, e.g., vacuum). Thus, there will generally be at least some ambient atmospheric air (along with oxygen) leaking into such an EFEM. Therefore, it may be desirable to quantify only how much oxygen is leaking into such an EFEM; if within acceptable limits, the EFEM may be considered to have an internal atmosphere sufficiently free of oxygen such that wafers passed therethrough are not at risk of unacceptable contamination. However, if the oxygen level within the EFEM exceeds such a threshold, the semiconductor processing tool controller may generate an error condition to alert the operator regarding a potentially unacceptable rate of oxygen leakage into the EFEM.

[0217] In such systems, one or more small surface-mounted gas sensors, e.g., oxygen sensor(s), may be included in the sensor-carrying wafer in addition to (or instead of) the airflow sensor(s). For example, low-profile side-mounted gas sensors, e.g., oxygen sensors, such as those commonly used in medical or safety devices, may be used. Such sensors may be electrochemical devices that consume fuel, e.g., oxygen, to produce an electrical output via a chemical reaction, and in some cases may have a packaging height less than 7 mm thick, which may make them suitable for use in the sensor-carrying wafer. Such sensor packages may be modified to be slightly thinner, for example, to achieve a total maximum thickness for the sensor-carrying wafer within, e.g., 5 mm, or may be used as is, with a total thickness for the sensor-carrying wafer greater than, e.g., 5 mm. For sensor-carrying wafers designed for use within an EFEM, height restrictions may be somewhat relaxed compared to sensor-carrying wafers configured for use within a semiconductor processing chamber. Thus, a slightly larger maximum thickness of the sensor-carrying wafer, e.g., 6 mm to 8 mm, may be permitted for sensor-carrying wafers that may not need to be delivered to the interior of a semiconductor processing chamber.

[0218] Controller 2674 (or controller 2574) may be further configured to analyze collected data from ambient atmospheric (or other) sensors on the sensor-mounted wafer and determine whether ambient atmospheric conditions within the portion of the semiconductor processing tool where measurements were taken using the sensor-mounted wafer meet one or more minimum required thresholds. If the ambient atmospheric conditions do not meet one or more minimum required thresholds, the controller may cause an error condition to be reported and may, for example, prevent operation of the semiconductor processing tool or at least relevant portions thereof until after a subsequent set of sensor wafer measurements indicates that the problem has been resolved or until an operator, for example, provides an override command.

[0219] While the exemplary sensor-carrying wafers described above have each tended to focus on sensor-carrying wafers including only a single type of sensor, e.g., one or more upward-facing optical sensors, one or more radially outward-facing optical sensors, one or more ambient air sensors, etc., it will be appreciated that sensor-carrying wafers may also be configured to include multiple different types of sensors, e.g., ambient air sensors and upward-facing and / or radially outward-facing optical sensors. Furthermore, some sensor-carrying wafers may further include one or more of one or more accelerometers, one or more proximity sensors, one or more relative humidity sensors, one or more temperature sensors, one or more sound sensors, etc.

[0220] It will also be appreciated that the sensor-equipped wafers described herein may employ sensors mounted on the top surface of the substrate (or other structure supported by the substrate), sensors mounted on the underside of the substrate, sensors mounted within the substrate, sensors mounted near the periphery of the substrate, and / or sensors mounted on the edge of the substrate.

[0221] As mentioned above, the controllers described herein can be part of a system that may include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more platforms, and / or specific processing components (such as wafer pedestals, gas flow systems, etc.) for processing. These systems can be integrated with electronics for controlling their operation before, during, and after processing of semiconductor wafers or substrates. The electronics, sometimes referred to as a “controller,” can control various components or subportions of one or more systems. Depending on the processing requirements and / or type of system, the controller can be programmed to control any of the processes disclosed herein, as well as various parameters affecting semiconductor processing, such as delivery of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and operation settings, wafer transport in and out of tools and other transport tools and / or load locks connected to or interfaced with a particular system.

[0222] In addition to the semiconductor processing tool controller, the sensor-equipped wafers described herein may also include a controller configured to cause data to be collected from one or more sensors on the sensor-equipped wafer and to communicate with, for example, the controller of the semiconductor processing tool (or another external controller) to receive commands from and / or send data to the semiconductor processing tool.

[0223] Generally, a controller may be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits may include firmware that stores program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or chips in the form of one or more microprocessors or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing specific measurement or calibration operations using the sensor-equipped wafer.

[0224] The controller, in some implementations, may be part of, coupled to, or a combination of a computer integrated with, coupled to, or otherwise networked to the system. For example, the controller may be in the “cloud” or in all or part of a fab host computer system that can enable remote access of wafer processing. The computer may enable remote access to the system for monitoring the current progress of a measurement or calibration operation using a sensor-equipped wafer, examining the history of past measurement or calibration operations using a sensor-equipped wafer, examining trends or performance metrics from multiple sensor-equipped wafer measurements of different semiconductor processing tools, etc. In some examples, a remote computer (e.g., a server) may provide process recipes to the system over a network that may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data specifying parameters for each of the measurement or calibration steps to be performed during one or more sensor-equipped wafer operations. It should be understood that the parameters may be specific to the type of measurement to be performed and the type of sensor-equipped wafer that the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by having one or more individual controllers networked together and working toward a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on the chamber in communication with one or more remotely located integrated circuits (e.g., at the platform level or as part of a remote computer) that combine to control the process on the chamber.

[0225] The sensor-equipped wafer may be used in example systems that may include, but are not limited to, a plasma etch chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a chamfered edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing system that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0226] As mentioned above, depending on the sensor-equipped wafer and / or the process step or steps to be performed by the tool, the controller may communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used in material transport that carries containers of wafers to and from tool locations and / or load ports in a semiconductor fabrication factory. For example, the controller may communicate with a remote system that may deliver a sensor-equipped wafer to a particular tool, e.g., via a FOUP, to enable the sensor-equipped wafer to be used in that tool to obtain measurements or data regarding various aspects of that tool.

[0227] The techniques described herein involving the use of sensor-carrying wafers may be practiced by one or more controllers, such as a controller located on the sensor-carrying wafer itself, or, in many cases, a separate controller, such as a controller located on the sensor-carrying wafer itself along with a controller associated with a semiconductor processing tool, which controllers may be configured, in whole or in part, to implement the techniques described herein.

[0228] Recognizing the possibility of such distributed processing arrangements, the term "collectively," as used herein with respect to memory devices and / or processors or various other items, should be understood to indicate that the referenced collection of items has the characteristics or provides the functionality associated with that collection. For example, if a server and client devices collectively store instructions for causing A, B, and C to occur, this encompasses at least the following scenarios: a) The server stores instructions for causing A, B, and C to occur, but the client device does not store instructions for causing A, B, and C to occur. b) The client device stores instructions for causing A, B, and C to occur, but the server does not store instructions for causing A, B, and C to occur. c) The server stores instructions for causing a proper subset of A, B, and C to occur, e.g., A and B but not C, and the client device stores instructions for causing a different proper subset of A, B, and C to occur, e.g., C but not A and B, where the instructions for causing each of A, B, and C to occur are stored on either or both the client device and the server, respectively. d) The server stores instructions for causing a subset of A, B, and C to occur, e.g., A and B but not C, and the client device stores instructions for causing a different subset of A, B, and C to occur, e.g., B and C but not A, where the instructions for causing each of A, B, and C to occur are stored on either or both the client device and the server, respectively. e) The server stores instructions to cause A and a portion of B to occur, and the client device stores instructions to cause C and the remainder of B to occur.

[0229] In all of the above scenarios, there are instructions stored between the server and the client device, collectively, to cause A, B, and C to occur; i.e., such instructions are stored on one or both devices; it will be recognized that use of the term "collectively," e.g., the server and client device, collectively, store instructions to cause A, B, and C to occur, encompasses all of the above scenarios as well as additional similar scenarios.

[0230] Similarly, a collection of processors, e.g., a first set of one or more processors and a second set of one or more processors, may be collectively caused to perform one or more actions, e.g., actions A, B, and C. As with the previous example, various permutations fall within the scope of such "collective" language. a) A first set of one or more processors may be caused to implement each of A, B, and C, and a second set of one or more processors may not implement any of A, B, or C. b) A second set of one or more processors may be caused to implement each of A, B, and C, and the first set of one or more processors may not implement any of A, B, or C. c) A first set of one or more processors may be caused to implement a proper subset of A, B, and C, and a second set of one or more processors may be caused to implement a different proper subset of A, B, and C to be implemented, such that between the two sets of processors, all of A, B, and C are caused to be implemented. d) A first set of one or more processors may be caused to implement A and a portion of B, and a second set of one or more processors may be caused to implement C and the remainder of B.

[0231] The term "wafer" as used herein may refer to a semiconductor wafer or substrate or other similar type of wafer or substrate, and in the context of a sensor-mounted wafer, the wafer may also be made from other materials, for example, carbon fiber.

[0232] It should also be understood that the use of order indicators herein, e.g., (a), (b), (c), ..., is for organizational purposes only and is not intended to impart a particular sequence or importance to the items associated with each order indicator. For example, "(a) obtain information regarding velocity, and (b) obtain information regarding position" would include obtaining information regarding position before obtaining information regarding velocity, obtaining information regarding velocity before obtaining information regarding position, and obtaining information regarding position simultaneously with obtaining information regarding velocity. However, there may be instances where some items associated with an order indicator inherently require a particular sequence, e.g., "(a) obtain information regarding velocity, (b) determine a first acceleration based on the information regarding velocity, and (c) obtain information regarding position." In this example, (a) would need to be performed after (b) because (b) depends on the information obtained in (a); however, (c) may be performed before or after either (a) or (b).

[0233] As used herein, the use of the word "each," such as in the phrase "for each <item> of one or more <items>" or "of each <item>," should be understood to include both single-item groups and multi-item groups; i.e., it should be understood that the phrase "for each..." is used in the sense that it is used in programming languages to refer to each of whatever group of items is being referred to. For example, if the group of items being referred to is a single item, then "each" will refer only to that single item and will not imply that there must be at least two of the items (even though dictionary definitions of "each" frequently define the term as referring to "every one of two or more things"). Similarly, it will be understood that a selected item may have one or more sub-items, and when a selection of one of those sub-items is made, if the selected item has only one sub-item, the selection of that one sub-item is inherent in the selection of the item itself.

[0234] It will also be understood that reference to multiple controllers configured in the aggregate to perform various functions is intended to encompass situations in which only one of the controllers is configured to perform all of the disclosed or described functions, as well as situations in which the various controllers each perform a subportion of the described functionality. For example, a sensor-mounted wafer may include a controller configured to control the operation of various sensors on the sensor-mounted wafer and communicate data therefrom to another controller associated with a semiconductor processing tool, which may then analyze such data to determine various operating parameters for the semiconductor processing tool.

[0235] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the disclosure. Thus, the scope of the claims is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the disclosure, the principles, and novel features disclosed herein.

[0236] Some features described herein in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented separately in multiple implementations or in any suitable subcombination. Moreover, although features may be described above as working in several combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be deleted from the combination, and the claimed combination may be directed to a subcombination or a variation of the subcombination.

[0237] Similarly, while operations are shown in the figures in a particular order, this should not be understood as requiring such operations to be performed in the particular order or sequential order shown, or that all of the shown operations be performed, to achieve desirable results. Furthermore, the figures may generally depict one or more exemplary processes in flow diagram form. However, other operations not shown may be incorporated into the generally depicted exemplary process. For example, one or more additional operations may be performed before, after, simultaneously with, or during any of the depicted operations. In some situations, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged in multiple software products. Furthermore, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

Claims

1. A device for evaluating the properties of a semiconductor processing tool or component, wherein the device is A base structure that is insertable through an opening in a semiconductor processing tool sized to receive a wafer for processing, and sized to be transportable by an object transporter of the semiconductor processing tool between at least two locations in the semiconductor processing tool, wherein the base structure has a first side surface configured to contact and be supported by a portion of the object transporter, and a second side surface facing in the opposite direction from the first side surface, One or more optical sensors, each optical sensor being oriented such that it has an upward field of view when the base structure is oriented with the first side facing downward, A controller, wherein the controller is connected to each of the one or more optical sensors in a communicative manner, A power supply configured to provide power to at least the controller, A device equipped with the following features.

2. The device according to claim 1, A device in which at least one of the one or more optical sensors is an imaging sensor.

3. The device according to claim 1, A device wherein at least one of the one or more optical sensors is coupled to one or more corresponding lenses that provide the optical sensor with a field of view of at least 30°.

4. The device according to claim 2 or 3, The device has two or more optical sensors, the two or more optical sensors being distributed across the device such that they have overlapping fields of view with respect to a focal plane parallel to the second side and located at a first distance from the second side.

5. The device according to claim 4, The first distance is between 2 mm and 100 mm in the device.

6. The device according to claim 5, wherein the region resulting from the intersection of the focal plane and the field of view of the optical sensor is [Math 1] A device having a total area of ​​at least 15% of the total area, where d is the nominal wafer diameter of the wafer configured to be processed by the semiconductor processing tool.

7. A device according to claim 2 or 3, wherein there are a plurality of optical sensors, and at least two of the optical sensors are located at different distances from the center point of the base structure.

8. A device according to any one of claims 1 to 3, A first support structure rotatably coupled to the base structure, A first rotation drive unit is configured to cause the first support structure to rotate about a first rotation axis and relative to the base structure in response to the reception of one or more first control signals, wherein at least one of the one or more optical sensors is directly or indirectly supported by the first support structure and is located at a distance offset from the first rotation axis in a direction perpendicular to the first rotation axis. A device that further enhances these features.

9. A device according to claim 8, comprising a plurality of optical sensors directly or indirectly supported by the first support structure, wherein at least two of the optical sensors supported by the first support structure are located at different distances from the first axis of rotation.

10. The device according to claim 9, The first axis of rotation is nominally centered on the base structure of the device.

11. The device according to claim 9, The first axis of rotation is offset from the center of the base structure of the device.

12. The device according to claim 11, A second support structure rotatably coupled to the first support structure, The second support structure includes a second rotation drive unit configured to cause the second support structure to rotate about a second rotation axis and relative to the first support structure in response to the reception of one or more second control signals, Furthermore, The second support structure is supported by the first support structure. At least one of the one or more optical sensors is supported by the second support structure. The device wherein the second axis of rotation is radially offset from the first axis of rotation.

13. A device according to any one of claims 1 to 3, The base structure is a device having a maximum dimension of 50% or less of the nominal wafer diameter of the wafer configured to be processed by the semiconductor processing tool.

14. A device according to any one of claims 1 to 3, The base structure has a maximum dimension of 50% or less of 300 mm. A device wherein at least one of the one or more optical sensors is located on the base structure at a location offset from the central axis of the base structure which is perpendicular to the second side surface.

15. The device according to claim 13, A device having multiple optical sensors, one of which is located close to the central axis of the base structure.

16. A device according to any one of claims 1 to 3, The system further comprises a first optical projection unit configured to project a first illumination pattern along a first axis, The first axis is at an oblique angle to the second side surface, The first axis is parallel to the second side surface and intersects a reference plane offset by a first distance from the second side surface. The first side is further from the reference plane than the second side, A device in which one or more optical sensors are arranged such that at least several locations where the reference plane and the first illumination pattern intersect are within the combined field of view of the one or more optical sensors.

17. The device according to claim 16, The first illumination pattern is a device that intersects the reference plane along a first line.

18. The device according to claim 17, further comprising a second optical projection unit, The second optical projection unit is configured to project a second illumination pattern along a second reference plane that is perpendicular to the second side surface and parallel to the first line on which the first illumination pattern intersects the reference plane. The device wherein the second illumination pattern intersects the reference plane along a second line that is parallel to the first line.

19. The device according to claim 16, The first lighting pattern intersects the reference plane at a plurality of individual locations distributed across the reference plane.

20. A device according to any one of claims 1 to 3, A device further comprising an inductive charging coil coupled to the power supply.

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