Wafer processing equipment with exposed sensing layer

Abstract

Examples include apparatus and methods for detecting particles, monitoring etch or deposition rates, or controlling the operation of wafer fabrication processes. In some examples, one or more microsensors are mounted on a wafer handling apparatus and are capable of measuring material deposition and removal rates in real time. Microsensors are selectively exposed such that the sensing layer of one microsensor is protected by a mask layer during active operation of another microsensor, and the protective mask layer can be removed to expose the sensing layer when the other microsensor reaches the end of its lifespan. Other embodiments are also described and claimed.

Description

[0001] This application is a divisional application of Chinese patent application No. 201780051612.5, filed on June 28, 2017, entitled "Wafer Processing Apparatus with Exposed Sensing Layer".

[0002] Cross-references to related applications

[0003] This application claims the benefit of U.S. Patent Application No. 15 / 247,717, filed August 25, 2016, the entire contents of which are incorporated herein by reference. Technical Field

[0004] The embodiments relate to the field of semiconductor processing, and more specifically to apparatus and methods for measuring material deposition or material removal in wafer processing tools. Background Technology

[0005] A primary consideration in the manufacture of semiconductor equipment is particle contamination of semiconductor wafers. This contamination typically occurs during one or more operations performed by wafer processing tools during the manufacture of the semiconductor equipment. For example, a wafer processing tool may include several interfaces (e.g., several chambers interconnected by loading and unloading mechanisms), and the actuation or operation of any of these system components may generate metallic or non-metallic particles, such as aluminum, stainless steel, zirconium, or other particles that may contaminate the semiconductor wafers within the tool. Those skilled in the art will understand that particles can originate from numerous sources within the wafer processing tool beyond interfaces and moving parts, and the above is thus provided by way of example.

[0006] To identify the source and / or root cause of particulate contamination, semiconductor wafers are periodically processed through one or more chambers of a wafer processing tool, and then subjected to a particulate inspection operation. The particulate inspection operation requires queuing the processed wafers for inspection by optical inspection equipment to identify the location and general size of particles, and then queuing the processed wafers for inspection by scanning electron microscopy, energy-dispersive spectroscopy, or other inspection techniques to determine the presence and / or composition of particles on the wafer. After the presence and composition of particles are detected, additional troubleshooting may be required to determine the operation performed by the wafer processing tool that actually caused the particulate contamination.

[0007] The manufacture of semiconductor devices can involve the deposition and removal of material (more specifically, semiconductor material) on a substrate using wafer processing tools employing processes such as deposition or etching. To accurately deposit or remove a specified amount of semiconductor material, film thickness measurement techniques can be used. For example, the material deposition rate and material removal rate can be indirectly measured by processing a wafer of semiconductor material for a given period of time and subsequently using an ellipsometry to measure the amount of film deposited or removed. Furthermore, sensors have been used to measure secondary factors related to the deposition / removal rate to indirectly estimate the deposition / removal rate during the wafer fabrication process. Summary of the Invention

[0008] Examples include wafer processing apparatuses with microsensors (e.g., MEMS-scaled dimensions and / or sensors fabricated using MEMS processes) to detect the amount or rate of material deposition or removal. In some examples, the wafer processing apparatus includes a particle monitoring device with microsensors for detecting particles within the wafer processing tool, or a wafer processing tool with microsensors for monitoring or controlling the wafer fabrication process. The microsensors of the wafer processing apparatus may include a sensing layer and a mask layer configured such that the sensing layer can be selectively protected or exposed. Thus, the sensing layer of a microsensor can be protected by a mask layer, while another microsensor is exposed to actively sense particles and / or material deposition or removal. When the other microsensor reaches the end of its lifespan, the mask layer can be removed to expose the sensing layer. Therefore, the microsensors of the wafer processing apparatus can be updated without interrupting the wafer fabrication process (e.g., opening the chamber or process station of the wafer processing tool).

[0009] In embodiments, wafer processing equipment (e.g., wafer processing tools or particle monitoring devices) includes a first microsensor and a second microsensor. For example, the microsensors can be mounted within the chamber volume of a process chamber in a wafer processing tool, or they can be mounted on a support surface of the wafer substrate in a particle monitoring device. Each of the microsensors may include a sensing layer covered by a mask layer. More specifically, when different sensing layers of the same or different microsensors are monitoring the process, the sensing layers can be protected by the mask layer during stages of the wafer fabrication process. That is, the exposed sensing layer of an active microsensor can be open to the surrounding environment and / or chamber volume to monitor the wafer fabrication process. The sensor may have corresponding parameters (e.g., capacitance), and these parameters may change when material is removed from the sensor surface of the sensing layer. Therefore, when material is removed from the exposed sensing layer, the corresponding change in parameters can be detected to sense the etching process, such as the amount or rate of particle deposition or removal.

[0010] In one embodiment, the microsensor includes a mask layer with a different thickness. For example, the mask layer may cover the sensing layers of several microsensors, and the mask layer may have a layer profile including a variable thickness. Therefore, removal of the mask layer may result in the exposure of a first sensing layer before a second sensing layer, which allows for independent and selective exposure of the sensing layers for sensing at different times during the wafer fabrication process.

[0011] In one embodiment, the microsensor includes a mask layer made of different materials, which are susceptible to etching by different etchants. That is, the first mask layer covering the first sensing layer can be different from the second mask layer covering the second sensing layer. For example, the first mask layer may include an oxide, and the second mask layer may include a nitride. Therefore, an etchant that erodes oxides can be used to remove the first mask layer and expose the first sensing layer, and an etchant that erodes nitrides can be applied to remove the second mask layer and expose the second sensing layer. Thus, removal of the first mask layer may result in the first sensing layer being exposed at a different time than the second sensing layer, allowing for independent and selective exposure of the sensing layer for sensing at different times during the wafer fabrication process.

[0012] The foregoing description is not an exhaustive list of all aspects. It is contemplated that all systems and methods can be practiced through all suitable combinations of the various aspects summarized above and disclosed in the detailed embodiments below and specifically pointed out in the claims filed together with this application. Such combinations have particular advantages not specifically described in the foregoing description. Attached Figure Description

[0013] Figure 1 This is a diagram of a wafer processing system according to an embodiment.

[0014] Figure 2 This is an illustration of a particle monitoring device according to an embodiment.

[0015] Figure 3 This is a cross-sectional view of the particle monitoring device according to an embodiment.

[0016] Figure 4 This is a cross-sectional view of several microsensors mounted on a wafer processing tool according to an embodiment.

[0017] Figure 5 This is a block diagram of the electronic circuitry of a particle monitoring device or wafer processing tool according to an embodiment.

[0018] Figure 6 This is a cross-sectional view of several microsensors having a multilayer structure including a selectively exposed sensing layer, according to an embodiment.

[0019] Figure 7This is a cross-sectional view of several microsensors having a cover mask layer on top of a selectively exposed sensing layer, according to an embodiment.

[0020] Figure 8 This is a cross-sectional view of several microsensors having mask layers of different materials on a selectively exposed sensing layer, according to an embodiment.

[0021] Figure 9 This is a perspective view of the microsensors of the wafer processing system according to an embodiment.

[0022] Figure 10 This is a perspective view of the microsensors of the wafer processing system according to an embodiment.

[0023] Figure 11 According to the embodiments Figure 10 A cross-sectional view of the microsensor of the wafer processing system taken near line segment AA.

[0024] Figure 12 This is a schematic diagram of a transistor sensor type microsensor in a wafer processing system according to an embodiment.

[0025] Figure 13 This is a schematic diagram of a micro-resonator type micro-sensor in a wafer processing system according to an embodiment.

[0026] Figure 14 This is a schematic diagram of a microsensor of the optical sensor type according to an embodiment of a wafer processing system.

[0027] Figure 15 This is a flowchart illustrating the operation of a method for updating a microsensor of a wafer processing apparatus according to an embodiment.

[0028] Figures 16A to 16C This is a cross-sectional view illustrating the operation of a method for updating a microsensor of a wafer processing apparatus according to an embodiment.

[0029] Figure 17 This is a flowchart illustrating the operation of a method for updating a microsensor of a wafer processing apparatus according to an embodiment.

[0030] Figures 18A to 18F This is a cross-sectional view illustrating the operation of a method for updating a microsensor of a wafer processing apparatus according to an embodiment.

[0031] Figure 19 A block diagram of an exemplary computer system according to an embodiment of a wafer processing system is shown. Detailed Implementation

[0032] Apparatus and methods for particle inspection, etch / deposition rate monitoring, or other manufacturing or control processes in wafer fabrication are described according to various embodiments. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent to those skilled in the art that the embodiments may be practiced without these specific details. In other instances, well-known aspects have not been described in detail so as not to unnecessarily obscure the embodiments. Furthermore, it should be understood that the various embodiments illustrated in the accompanying drawings are schematic representations and are not necessarily drawn to scale.

[0033] Existing techniques for measuring material deposition and removal do not provide real-time measurement and control of wafer fabrication processes, or provide estimates of material deposition / removal based on correlations with secondary factors rather than directly measuring deposition / removal. For example, ellipsometers can be used to measure film thickness; however, because ellipsometers are periodic monitors, they cannot detect real-time deviations or drifts in deposition / removal rates during normal production runs. Furthermore, sensors installed in the process chambers of wafer processing tools to measure secondary factors (such as RF matching position or gas concentration in the plasma) do not directly measure the variable of interest (deposition / removal rate), and such measurements become more challenging in chambers without plasma.

[0034] The following describes a wafer processing apparatus having microsensors for measuring material deposition or removal under all pressure conditions, such as vacuum conditions and plasma-free conditions. For example, the microsensors mounted on the process chamber may include a sensor surface, and parameters (e.g., capacitance) of the microsensors may change as material is deposited on or removed from the sensor surface. Therefore, real-time measurement of the amount or rate of material deposition or removal, and the uniformity of such amount or rate, can be monitored and used to control the wafer fabrication process performed by the wafer processing system.

[0035] Microsensors used for real-time measurements of wafer fabrication processes will change over time. More specifically, sensor surfaces can be removed (either by etching or by deposition) by design, and these surfaces may become roughened, their surface area may change, or they may oxidize. These changes can affect the sensitivity and reliability of the microsensors. For example, after dozens of wafer processing cycles, a microsensor may lose reliability, requiring the process chamber to be opened for cleaning or replacement. However, such updates to the microsensors may disrupt the wafer fabrication process flow, necessitating the expansion of the wafer processing equipment's sensing capabilities without halting the wafer fabrication process as the microsensors degrade.

[0036] In one aspect, a wafer processing apparatus may include selectively exposed microsensors to allow different microsensors to replace degraded microsensors. For example, each microsensor may include several sensing layers separated by an intermediate mask layer. Thus, after a first sensing layer degrades, the sensing layer and one or more intermediate mask layers can be removed to expose the underlying sensing layer for active operation. Alternatively, several laterally separated sensing layers can be covered by a cover mask layer of variable thickness. Thus, the cover mask layer can be etched to sequentially expose the sensing layers based on the thickness of the cover mask layer covering the respective sensing layer. For example, when the cover mask layer is removed, a second sensing layer under a second thickness of material, greater than the first thickness, can be exposed some time after the first sensing layer under a first thickness of material is exposed. Using a sensor scheme that allows selective exposure of new sensing layers to replace degraded sensing layers can increase the lifetime of the wafer processing apparatus and, more specifically, can increase the number of wafer processing cycles of the wafer fabrication process that can be performed before the process chamber must be opened for sensor maintenance.

[0037] It should be understood that the wafer processing systems and methods described below can be used in any form factor or process for depositing or removing material onto or from a substrate. More specifically, although the wafer processing systems and methods are described with respect to wafer processing for manufacturing integrated circuits, the apparatus and methods are also applicable to other technologies, such as displays in the electronics industry and / or photovoltaic cells in the solar energy industry.

[0038] Reference Figure 1 The illustration shows a wafer processing system according to an embodiment. The wafer processing system 100 may include a wafer processing tool 102 communicatively coupled to a computer system 104 via a communication link 106. The communication link 106 may be a wired or wireless connection, i.e., the wafer processing tool 102 may communicate directly or wirelessly with the computer system 104. It should be understood that although data can be transmitted from the wafer processing tool 102 and / or devices within the wafer processing tool 102 via the communication link 106, in some embodiments, the devices within the wafer processing tool 102 may be passive devices. That is, the devices may be processed by the wafer processing tool 102, and the devices may undergo changes, which can be measured after the devices are removed from the wafer processing tool 102. For example, this may be a feature of a particle inspection tool or an etching / deposition monitoring tool as described below.

[0039] The wafer processing tool 102 may include a buffer chamber 108 physically connected to the factory interface 110 via one or more loading / unloading mechanisms 112. Furthermore, one or more process chambers 114 may be physically connected to the buffer chamber 108 via one or more corresponding loading / unloading mechanisms 112. The buffer chamber 108 may serve as an intermediate volume larger than the corresponding volume of the process chambers 114, and this intermediate volume is maintained at a low pressure even at pressures higher than those within the process chambers 114. Therefore, semiconductor wafers (e.g., silicon wafers) can be moved between the chambers of the wafer processing tool 102 under vacuum conditions during the manufacture of semiconductor equipment. This movement can be achieved by various devices (e.g., robots, robotic arms, shuttles, etc.) included in the wafer processing tool 102.

[0040] Various manufacturing operations can be performed in the process chamber 114. For example, at least one process chamber 114 can be an etching chamber, a deposition chamber, a semiconductor lithography tool chamber, or any other semiconductor process chamber. Thus, the process chamber 114 can be used to perform wafer manufacturing processes under vacuum conditions, atmospheric conditions, or any other pressure scheme.

[0041] In addition to varying pressure schemes, process chamber 114 can also be used to perform manufacturing processes with different energy conditions. For example, process chamber 114 can be a radical-driven etching chamber or a deposition chamber that does not contain plasma. That is, process chamber 114 can be in a plasma-free state during wafer fabrication processes. Alternatively, process chamber 114 can be a plasma-based etching chamber or deposition chamber.

[0042] During the wafer fabrication process, semiconductor wafers can be transferred from buffer chamber 108 to one of the process chambers 114 via loading / unloading mechanism 112. Process chamber 114 may be equipped with, for example, a vacuum pump and / or a turbopump. Figure 4 The chamber pressure is reduced to a vacuum condition. In the context of this description, a vacuum condition can be any pressure less than 0.5 atm. In an embodiment, a vacuum condition exists in the process chamber 114 when the process chamber 114 has a chamber pressure lower than that of the buffer chamber 108 (e.g., less than 100 mTorr). Therefore, manufacturing operations performed in the process chamber 114 can be carried out under vacuum conditions.

[0043] One or more particles may be generated during manufacturing operations performed in process chamber 114. For example, particles may be metallic or non-metallic particles emitted into process chamber 114 when a specific operation occurs (e.g., when a valve on loading / unloading mechanism 112 is opened, when the loading / unloading mechanism door is locked, when the lifting lever is moving, or when any other tooling operation occurs). The emitted particles may land on a semiconductor wafer, and the landing location and time of the particles may correspond to a source of particle contamination. For example, particles may land on a semiconductor wafer closer to loading / unloading mechanism 112 at the time loading / unloading mechanism 112 is closed, indicating that components of loading / unloading mechanism 112 and / or the actuation of loading / unloading mechanism 112 are a source of particles. Therefore, it can be seen that particle monitoring, which provides information about the location and time of particle landing on a semiconductor wafer, can be used to determine the source of particle contamination.

[0044] Reference Figure 2 The illustration shows a particle monitoring device according to an embodiment. The particle monitoring device 200 can be configured to move between chambers (e.g., buffer chamber 108 and / or process chamber 114) of a wafer processing tool 102. For example, the particle monitoring device 200 may include a wafer substrate 202 having an overall shape factor and / or the same material and shape as a semiconductor wafer. That is, the wafer substrate 202 may be at least partially composed of a semiconductor material (e.g., crystalline silicon). Furthermore, the wafer substrate 202 may have a wafer shape factor that is substantially disk-shaped and includes a support surface 204 having a diameter 206. The support surface 204 may be the upper surface of the disk, and the bottom surface of the wafer substrate 202 (not shown) may be spaced apart from the support surface 204 by a thickness 208. In embodiments, the wafer shape factor of the wafer substrate 202 includes a diameter 206 between 95 and 455 mm; for example, the diameter 206 may be designated as 100 mm, 300 mm, or 450 mm. Furthermore, the wafer shape factor of the wafer substrate 202 may include a thickness 208 of less than 1 mm, such as 525 μm, 775 μm, or 925 μm. The thickness 208 may also be greater than 1 mm, for example, from a few millimeters to 10 mm. Therefore, readily available wafer materials and typical wafer fabrication processes and equipment can be used to fabricate the particle monitoring device 200, and the particle monitoring device 200 can substantially simulate a semiconductor wafer when processed by the wafer processing tool 102.

[0045] The particle monitoring device 200 may include several microsensors mounted on a support surface 204 at predetermined locations. The microsensors may be one or more of the types described below. For example, a microsensor 210 may include a corresponding sensing layer covered by a corresponding mask layer. The microsensor 210 may include corresponding parameters and a corresponding sensor surface on the corresponding sensing layer. Therefore, the corresponding parameters may change when material is deposited on or removed from the corresponding sensor surface. A large number of microsensors 210 (e.g., thousands to millions of microsensors) may be mounted on the support surface 204. Each microsensor 210 may have a known location. For example, a first microsensor 212 may be located at a first location, and a second microsensor 214 may be located at a second location. The second location may have a known location relative to the first location or relative to some other reference point on the particle monitoring device 200.

[0046] The microsensors 210 can be randomly distributed on the support surface 204, or they can be arranged according to a predetermined pattern. For example, Figure 2 The microsensors 210 shown are randomly distributed on the support surface 204, although the absolute or relative positions of the microsensors 210 may be predetermined and known. In this embodiment, the microsensors 210 are arranged in a predetermined pattern (e.g., a grid pattern, a concentric circle pattern, a spiral pattern, etc.). Such a pattern can be achieved using known etching processes to establish the microsensors 210 at precise locations on the support surface 204 of the particle monitoring device 200.

[0047] In one embodiment, the microsensors 210 are distributed across a large portion of the surface area of ​​the support surface 204. For example, the outer contour drawn by the outermost microsensors 210 of the microsensor array can depict the array area, which is at least half the surface area of ​​the support surface 204. In another embodiment, the array area is at least 75% of the surface area, for example, greater than 90% of the surface area of ​​the support surface 204.

[0048] The microsensors 210 of the particle monitoring device 200 can be interconnected with each other or with other circuitry via one or more electrical connectors. For example, the microsensors 210 can be connected in series via electrical traces 216 running on the support surface 204. Alternatively or additionally, several microsensors 210 can be electrically connected in parallel via corresponding electrical traces 216. Thus, electrical connections can be made between the microsensors 210, or the microsensors 210 can be connected to wafer electronics (i.e., electronic circuitry 218) using electrical traces, leads, vias, and other known types of electrical connectors.

[0049] Each microsensor 210 of the particle monitoring device 200 may be configured to sense a change in a given parameter when a particle interacts with the sensor. For example, a microsensor 210 may include a capacitive microsensor as described below and may have capacitance that changes when material is deposited on or removed from the sensor surface of the microsensor 210. Thus, when the microsensor 210 receives a particle within a chamber (e.g., process chamber 114) of the wafer processing tool 102, the capacitance may change. Here, the term “receive” refers to the interaction between the particle and the microsensor 210 that affects the capacitance. It should be understood that, as described below, the particle monitoring device 200 may include other types of microsensors, and therefore different parameters may be sensed when receiving particles through such microsensors. For example, as described below, the parameter may be the voltage, current, or another physical or electrical characteristic of the microsensor that changes when a particle falls on, approaches, or passes through, or impacts the microsensor. Other particle-sensor interactions will be understood by those skilled in the art upon reading this description.

[0050] Reference Figure 3 A cross-sectional view of a particle monitoring device according to an embodiment is shown. Similar to the loading and handling of typical semiconductor wafers, microsensors 210 can be packaged on a wafer substrate 202, and the microsensors 210 can be automatically loaded into the system and moved through the system. Therefore, the microsensors 210 can experience the same environment as in the production of semiconductor wafers. In an embodiment, a sensor layer 302 having a plurality of microsensors 210 covers at least a portion of the wafer substrate 202. Therefore, the microsensors 210 of the sensor layer 302 are mounted on a support surface 204 of the wafer substrate 202.

[0051] As described below, the sensor layer 302 is not to be confused with the sensing layer. More specifically, the sensor layer 302 may be a layer of a wafer processing apparatus in which one or more microsensors 210 are disposed, while the sensing layer may be one of several layers of a single microsensor 210 that may be exposed to the surrounding environment to detect etch / deposition rates, gas concentrations, byproduct accumulation, particles, etc.

[0052] Any part of the particle monitoring device 200 can be constructed from a standard silicon-on-insulator (SOI) substrate or a stack of other types of wafers. Wafers can be combined at the wafer level, i.e., a combination of individual wafers with integrally formed functional components. Alternatively, the wafers can have individual modules, such as wafers, sensors, etc., combined before or after the particle monitoring device 200 is constructed. It should be understood that such processes can allow the use of SOI technology to optimize the etching of sensors, high-temperature electronics, or other modules / components integrated into the particle monitoring device 200. It should be understood that such methods can also be used to fabricate parts of the wafer processing equipment described below, such as the microsensor 210 in the wafer fabrication processing equipment.

[0053] In this embodiment, the wafer substrate 202 is configured to protect the electronic circuitry 218 of the particle monitoring device 200 from plasma in the wafer processing tool 102. Thus, the wafer substrate 202 may include the electronic circuitry 218 (e.g., wafer electronics) sandwiched between a top layer 306 and a bottom layer 308. For example, the electronic circuitry 218 may include a power source 304, such as a thin-film battery. The thin-film battery can be sealed between the silicon layers 306, 308, and thus the two silicon wafers can protect the thin-film battery from plasma intrusion from either the top or bottom. Furthermore, the power source 304 can be protected from side plasma intrusion by a barrier seal 310. The barrier seal 310 can be sandwiched between the top layer 306 and the bottom layer 308 around the power source 304. More specifically, the barrier seal 310 may extend around the circumference of the wafer substrate 202 to form a protective wall surrounding the sides of the power source 304. Therefore, the power source 304 can be sealed within the wafer substrate 202.

[0054] Power source 304 can be electrically connected to one or more components of electronic circuitry 218 in top layer 306 and / or sensor layer 302. For example, electronic circuitry 218 (e.g., control electronics such as processors, memory, or communication electronics) can be embedded in top layer 306 of wafer substrate 202. Power source 304 can be connected to electronic circuitry 218 in top layer 306 via electrical connections (such as through-silicon vias extending through one or more layers of particle monitoring device 200). Similarly, power source 304 and / or electronic circuitry 218 (e.g., processor) in top layer 306 can be electrically connected to microsensor 210 in sensor layer 302 via traces or vias. Thus, power source 304 can be electrically coupled to processor, microsensor 210, or other electronic circuitry 218 of electronic circuitry 218 to power electronic devices.

[0055] It should be understood that physical, chemical, and electrical protection can be provided for certain areas of the wafer processing tool 200 and / or wafer processing equipment by incorporating electronic circuitry 218 onto the wafer substrate at the module or wafer level and then encapsulating the components. For example, batteries, processors, sensors, wireless communication modules, etc., can be incorporated and then encapsulated, for example by a barrier layer 312. However, some components may be exposed to the wafer processing environment. For example, microsensor 210 may be exposed to the wafer processing tool 200 or wafer processing equipment as described below to monitor etching and deposition processes.

[0056] Microsensor 210 may be exposed to plasma within wafer processing tool 102, and therefore the sensor may eventually wear out. Sensor solutions for extending the overall lifespan of the sensor are described below. However, encapsulating microsensor 210 to make it recyclable may be advantageous. In an embodiment, the encapsulation of microsensor 210 includes a barrier layer 312 between microsensor 210 and an underlying substrate. For example, in the case of particle monitoring device 200, barrier layer 312 may be disposed between microsensor 210 and support surface 204 of wafer substrate 202. Microsensor 210 can be electrically connected to wafer electronics (i.e., electronic circuitry 218) through barrier layer 312 using known interconnect technologies (such as through-silicon vias). Barrier layer 312 between control electronics and the sensor can protect the electronics during recycling. For example, microsensor 210 can be removed by a stripping agent (i.e., by plasma, gas, or liquid etchant), and barrier layer 312 may not be removable by the same stripping agent. That is, the barrier layer 312 can be any conductive or insulating material that is unaffected by stripping agents (such as vapor or liquid etchants). Therefore, once the microsensors 210 reach the end of their lifespan, plasma can be applied to strip the microsensors from the barrier layer 312 of the sensor layer 302 without degrading the electronic circuitry 218 embedded in the wafer substrate 202. Similarly, mechanical stripping can be used to remove worn sensors. A new sensor layer 302 with a new set of microsensors 210 can then be formed on the barrier layer 312, thereby refurbishing the particle monitoring device 200 at a lower cost than forming a completely new particle monitoring device 200.

[0057] Components of the particle monitoring device 200 can be formed using known semiconductor processes and techniques. For example, as described above, through-silicon vias can be used to form electrical connections between the sensor and the electronic circuitry 218 through the barrier layer 312 and / or the wafer substrate 202. Furthermore, known techniques can be used to embed components within layers of the particle monitoring device 200. For example, a microsensor 210 can be formed separately and then mounted on the barrier layer 312 using flip-chip technology during recycling.

[0058] The implementation of the microsensor 210 in the particle monitoring device 200 represents an embodiment using the microsensor 210 for particle detection. Other uses for the microsensor 210 exist in wafer fabrication processing equipment and methods. For example, the microsensor 210 can be mounted on the wafer processing tool 102 to detect or measure the etch / deposition rate, and such data can be used to control wafer fabrication processes, such as etching or deposition processes.

[0059] Reference Figure 4 The diagram shows a cross-sectional view of several microsensors mounted on a wafer processing tool according to an embodiment. A wafer 402 (e.g., a wafer substrate 202 of a semiconductor material wafer or particle monitoring device 200) can undergo wafer fabrication processes within the process chamber 114 of the wafer processing tool 102. As the wafer 402 moves through the wafer processing tool 102, it may experience different pressure conditions. For example, the semiconductor wafer 402 can be inserted into the fab interface 110 under atmospheric conditions. Then, as the semiconductor wafer 402 enters the loading / unloading mechanism 112 between the fab interface 110 and the buffer chamber 108, the loading / unloading mechanism 112 can be brought to a vacuum condition of 120 millitor. The semiconductor wafer 402 can then enter the buffer chamber 108 from the loading / unloading mechanism 112, where the pressure in the buffer chamber 108 is 100 millitor.

[0060] Wafer 402 can be transferred from buffer chamber 108 to one of the process chambers 114 via loading / unloading mechanism 112. For example, process chamber 114 may include a chamber wall 404 surrounding a chamber volume 406, and the chamber volume 406 may be sized to receive wafer 402. Therefore, semiconductor material can be deposited on or removed from wafer 402 during wafer fabrication processes within process chamber 114. During wafer fabrication processes, the chamber volume 406 of process chamber 114 may have a chamber pressure reduced to vacuum conditions using, for example, a vacuum source 408 (such as a vacuum pump and / or turbopump). In the context of this description, vacuum conditions can be any pressure less than 0.5 atm. In embodiments, vacuum conditions exist in process chamber 114 when process chamber 114 has a chamber pressure lower than that of buffer chamber 108 (e.g., less than 100 mTorr). Therefore, during the manufacturing operations of the wafer fabrication process, the process chamber 114 can be under vacuum conditions. Furthermore, the vacuum conditions can reduce or eliminate the gas mixture from the chamber volume 406, and thus the chamber volume 406 can be in a plasma-free state during the wafer fabrication process.

[0061] One or more microsensors (e.g., microsensor 210) may be mounted on the wafer processing tool 102. The microsensor may be one or more of the microsensor types described below. For example, microsensor 210 may include a corresponding sensing layer covered by a corresponding mask layer. Microsensor 210 may be mounted at one or more locations on the process chamber 114 within the chamber volume 406. More specifically, a plurality of microsensors 210 may be mounted at predetermined locations on the chamber wall 404 within the chamber volume 406.

[0062] In an embodiment, one or more microsensors 210 are mounted on a portion of the wafer processing tool 102 other than the chamber wall 404. For example, instead of mounting the microsensors 210 on the chamber wall 404, or in any other way, one or more microsensors 210 may be mounted on a wafer holder 410 within the process chamber 114. For example, the wafer holder 410 may be an electrostatic chuck having one or more electrodes for electrostatically holding the wafer 402 during wafer fabrication processes. The wafer holder 410 may include a holding surface 412 on which the wafer 402 is held. For example, the holding surface 412 may be a dielectric layer over the wafer holder 410, and the microsensors 210 may be mounted on the holding surface 412. More specifically, the microsensors 210 may be mounted on the holding surface 412 in regions adjacent to and / or laterally offset from the wafer 402 during wafer fabrication processes. For example, the processing kit may include a ring around the wafer 402 on the holding surface 412, and the microsensor 210 may be mounted on the processing kit.

[0063] It is anticipated that the microsensor 210 can be positioned sufficiently close to the wafer 402 within the process chamber 114, or that the microsensor 210 can be integrated into a consumable or non-consumable component (e.g., wafer holder 410) of the process chamber 114 to detect changes in the material deposition or removal rate of the wafer 402. For example, the wafer 402 may have a forward-facing surface (i.e., a surface facing away from the holder surface 412 and towards the plasma), and the microsensor 210 may be mounted on the holder surface 412 such that the sensor surface sensitive to material deposition / removal faces forward.

[0064] It should be understood that the microsensor 210 can be mounted on the wafer processing tool 102 at locations other than those within the process chamber 114. For example, one or more microsensors may be mounted on, within, or near the loading / unloading mechanism 112. Similarly, the microsensor 210 may be mounted on, within, or near a gas line (not shown) of the wafer processing tool 102, a pressure control valve 414 of the wafer processing tool 102 controlling the flow to the vacuum source 408, a robot of the wafer processing tool 102, or a lifting rod of the wafer processing tool 102, as defined above, along with several example locations. Depending on the desired specific processing measurements and controls, the microsensor 210 may be mounted near other locations on the wafer processing tool 102. Here, "near" is used as a relative term, but it should be understood that the presence of the microsensor 210 near a specific component of the wafer processing tool 102 is intended to describe a distance such that particles or material deposited on or removed from the component may statistically be likely to interact with the mounted sensor. Examples of these interactions are further described with respect to the methods described below.

[0065] As used herein, the term "micro" can refer to a descriptive size of certain sensors or structures according to embodiments. For example, the term "microsensor" can refer to a capacitive sensor having a size on a scale from nanometers to 100 μm. That is, in embodiments, the microsensor 210 described below can have typical sizes of individual cells connected in parallel or in series in the range of 0.05 to 100 μm. Thus, the microsensor 210 described herein can be easily distinguished from other sensor types (e.g., microbalances), which are instruments capable of accurately measuring weights down to one millionth of a gram. That is, microbalances can measure weight on a microscale, but not within the same size range as the microsensor described herein. This difference in size range is advantageous, at least because several microsensors (e.g., thousands) can be fitted into chamber volume 406 or other locations on wafer processing tool 102, whereas several microbalances may not be fitted into chamber volume 406 whose size is set to receive semiconductor wafer 402.

[0066] As used herein, the term "microsensor" can also refer to a sensor fabricated using materials and manufacturing processes associated with microelectromechanical systems (MEMS). That is, the microsensor 210 described herein can be fabricated using MEMS processes (e.g., deposition, patterning, etching, etc.). Therefore, the microsensor 210 can be a MEMS scaling sensor having dimensions and structures formed using MEMS processes. However, it should be understood that the embodiments are not necessarily limited thereto, and certain aspects of the embodiments can be applied to scaling at larger and potentially smaller scales.

[0067] While only one microsensor can be mounted on the wafer processing tool 102, many microsensors (e.g., hundreds to millions of microsensors) can be fitted into the chamber volume 406 or mounted at other locations on the wafer processing tool 102. That is, given the MEMS-scale dimensions of the microsensors described below, many microsensors can be distributed along the wafer processing tool 102 (e.g., around the chamber wall 404 (or other components of the wafer processing tool 102)) to monitor wafer fabrication process parameters in real time, such as the deposition / removal of semiconductor material within the process chamber 114.

[0068] Each microsensor 210 may have a known location. For example, a first microsensor may be located at a first predetermined location on the wafer processing tool 102 (e.g., a first location within the chamber volume 406), and a second microsensor may be located at a second predetermined location on the wafer processing tool 102 (e.g., a second location within the chamber volume 406). The microsensors 210 may be randomly distributed on the process chamber 114 or distributed in a predetermined pattern. For example, the second location may have a known location relative to the first location or relative to some other reference point on the process chamber 114. Therefore, by comparing instantaneous measurements from the first and second microsensors, the uniformity of material deposition / removal can be determined as described below.

[0069] Wafer processing tool 102 may include other sensors and / or measuring instruments to detect process parameters of the wafer fabrication process. These other sensors and / or measuring instruments may not be microsensors. For example, relative to the MEMS scaling sensors described below, wafer processing tool 102 may include a spectrometer 416 mounted on or otherwise mounted in the process chamber 114 to detect the optical emission spectrum (OES) signature of the chamber volume 406 during the wafer fabrication process. The OES signature can identify the type and quantity of elements within the chamber volume 406. For example, the OES signature can identify what chemical elements are present in the plasma within the chamber volume 406 during the wafer fabrication process. Other sensors may be used to detect other process parameters of the wafer fabrication process performed in the chamber volume 406. Such other sensors may include electrical sensors for measuring the power delivered to the process chamber 114 or wafer 402, electrical sensors for measuring the electrical characteristics of the wafer holder 410, and so on. Such a sensor may not measure the actual amount or rate of deposition / removal of semiconductor material 1108, but may be relevant to the actual deposition / removal measurements performed by microsensor 210 for the following reasons.

[0070] Other sensors can also be used to collect information related to the presence of particles in the wafer processing tool 102. For example, one or more measuring devices (e.g., accelerometers (not shown)) can be mounted on the moving parts of the wafer processing tool 102. In embodiments, a robot or robotic arm includes an accelerometer for sensing the robot's motion. Alternatively, a loading / unloading mechanism door includes an accelerometer. Thus, process parameters of the wafer manufacturing process (e.g., motion data representing robot movement) can be detected by the accelerometer, and these process parameters can be correlated with particle sensing data collected from the microsensor 210 to determine the source of the particles. The application of such other sensors (e.g., accelerometers) is further described below.

[0071] The microsensors 210 and / or the measuring instruments or devices of the wafer processing tool 102 can be interconnected with each other or with other circuitry via one or more electrical connectors. For example, the microsensors 210 can be connected in series via electrical traces running over the chamber wall 404 and / or the wafer holder 410. Alternatively or additionally, several microsensors 210 can be electrically connected in parallel via corresponding electrical traces 216. Thus, electrical connections can be made between the microsensors 210, and / or the microsensors 210 can be connected to the electronic circuitry 218 using electrical traces, leads, vias, and other known types of electrical connectors.

[0072] Reference Figure 5 This illustration shows a block diagram of the electronic circuitry of a particle monitoring device or wafer processing tool according to an embodiment. The electronic circuitry 218 of the particle monitoring device 200 or wafer processing tool 102 can be supported by the wafer 402 or the underlying structure of the wafer processing tool 102. For example, as described above, the electronic circuitry 218 can be mounted on the top layer 306 of the particle monitoring device 200. The electronic circuitry 218 can be enclosed in a housing. The housing and / or electronic components of the electronic circuitry 218 can be integrated into the wafer 402; for example, the housing can be a wafer substrate layer that seals the electronic circuitry 218. Alternatively, the housing can be mounted on the wafer processing tool 102, for example, on the chamber wall 404 or the wafer holder 410. Similarly, the housing can be mounted on another portion of the wafer processing tool 102, for example, on the outer surface outside the chamber volume 406. Therefore, the electronic circuitry 218 can be co-located or remotely positioned relative to the microsensor 210. Nevertheless, even when remotely mounted relative to the microsensor 210, the electronic circuitry 218 can be electrically connected to the microsensor 210 via one or more input / output (I / O) connections 502 (e.g., traces, leads, or vias).

[0073] The electronic circuitry 218 of the wafer processing apparatus may include a clock 504. As is known in the art, clock 504 may be an electronic circuit with an electronic oscillator (e.g., a quartz crystal) to output an electrical signal with a precise frequency. Therefore, clock 504 may be configured to output a time value corresponding to an electrical signal received via I / O connection 502. The time value may be an absolute time value independent of other operations, or the time value may be synchronized with other clocks in the wafer processing apparatus. For example, clock 504 may be synchronized with the system clock of wafer processing tool 102 or the system clock of a host computer linked to the manufacturing facility of wafer processing tool 102, such that the time value output by clock 504 corresponds to a system time value and / or system operation output or controlled by the system clock. Clock 504 may be configured to initiate the output of the time value when a specific process operation occurs. The electronic circuitry 218 of the wafer processing apparatus may include a network interface device 506 for sending and receiving communications between wafer processing tool 102 and the host computer.

[0074] The electronic circuitry 218 of the wafer processing apparatus may include a processor 508. The processor 508 may be operatively coupled (e.g., electrically connected via bus 510 and / or traces) to a clock 504. The processor 508 represents one or more general-purpose processing devices, such as a microprocessor, a central processing unit, etc. More specifically, the processor 508 may be a Complex Instruction Set Computing (CISC) microprocessor, a Reduced Instruction Set Computing (RISC) microprocessor, a Very Long Instruction Word (VLIW) microprocessor, a processor implementing other instruction sets, or a processor implementing a combination of instruction sets. The processor 508 may also be one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), network processors, etc.

[0075] Processor 508 is configured to execute processing logic for performing the operations described herein. For example, processor 508 may be configured to receive and analyze input signals from several microsensors 210 located at different predetermined locations on particle monitoring equipment 200 or wafer processing tool 102. Therefore, processor 508 can determine and record data associated with the microsensors 210 operatively connected to processor 508. For example, processor 508 can record the position of the microsensor 210 when the capacitance of the microsensor changes. Processor 508 may also receive time value outputs from clock 504 corresponding to each received input signal and can record the time values ​​output to memory as timestamps. Therefore, processor 508 can compare the input signals from several microsensors 210 to, for example, determine the uniformity of the wafer manufacturing process at a given time. Processor 508 may be configured to determine other types of information based on signals received from the microsensors 210. For example, as described below, input signals received from one or more microsensors 210 may be used to terminate the wafer manufacturing process or determine the root cause of changes in the wafer manufacturing process.

[0076] As described herein, processor 508 may provide other functions. For example, processor 508 may include signal processing functions, such as converting analog signals from microsensor 210 into digital signals. Of course, a dedicated digital-to-analog converter may also be used for such a purpose. Similarly, other electronic devices may be used for any of the processing functions described, such as filtering displacement current, performing tasks for logical determination of data (e.g., referring to a lookup table), applying correction factors, etc. It should also be understood that, as is known, such processing can be performed locally or in a distributed manner. Therefore, for the sake of brevity, such electronic and processing techniques are not discussed in detail herein.

[0077] Monitoring of the microsensors 210 can be performed individually or in groups by the processor 508. That is, the processor 508 can monitor and record individual data for each microsensor 210. Therefore, each microsensor 210 can be individually identifiable, for example, by a unique sensor identification number associated with location or other sensor-specific data. In embodiments, the microsensors 210 can be monitored in groups. For example, the processor 508 can monitor and record group data for groups of one or more microsensors 210. These groups can be referred to as sensor blocks, and each sensor block can have a corresponding power source and processor. That is, the sensor blocks can operate independently of each other and be monitored or controlled individually. Therefore, groups of microsensors 210 can be associated with location or other group-specific data corresponding to the overall sensor group.

[0078] The electronic circuitry 218 of the wafer processing apparatus may include a memory 512 mounted on, for example, the wafer substrate 202 or the chamber wall 404. The memory 512 may include main memory (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) (e.g., synchronous DRAM (SDRAM) or bus-type DRAM (RDRAM)), static memory (e.g., flash memory, static random access memory (SRAM), etc.), or auxiliary memory (e.g., data storage device). The processor 508 may communicate with the memory 512 via a bus 510 or other electrical connection. Therefore, the processor 508 may be operatively coupled to the memory 512 to record the predetermined location of the triggered microsensor 210 and the time value output by the clock 504 in the memory 512. That is, the memory 512 may record the time when particles or material are deposited on or removed from the microsensor 210, and the location of the microsensor affected when material falls onto or leaves the microsensor 210.

[0079] The electronic circuitry 218 of the wafer processing tool 102 may include a power source 304 as described above. The power source 304 may include a battery, capacitor bank, or other known power source. The power source 304 may be electrically connected to and powered by one or more components of the electronic circuitry 218 (e.g., microsensor 210, clock 504, processor 508, or memory 512) via bus 510.

[0080] The electronic circuitry 218 of the wafer processing tool 102 may include additional components. For example, the electronic circuitry 218 may include an accelerometer 514 that triggers a clock 504 to start outputting a time value when the particle monitoring device 200 stops moving (e.g., after the particle monitoring device 200 has been loaded into a specific process chamber 114 of the wafer processing tool 102). Thus, the time value can provide information about when the particle monitoring device 200 was loaded into a specific processing station of the wafer processing tool 102. The electronic circuitry 218 may include a frequency source 516 (e.g., a wide-frequency source 516) or a detector 518. The frequency source 516 and detector 518 may have specific applications related to specific embodiments of the microsensor 210 of the wafer processing tool 102. For example, as described below, the frequency source 516 and detector 518 may be used to drive and monitor a microresonator-type microsensor.

[0081] The components of the electronic circuit 218 described above are illustrative of the range of sensors that can be used, and not limiting. For example, additional sensors (such as temperature sensor 520) can be integrated into the fabrication of the wafer processing tool 102. Temperature sensor 520 can monitor the temperature of one or more components (e.g., chamber volume 406) in the wafer processing tool 102. Various embodiments of the microsensor 210 will now be described. The configuration and illustrations of the microsensor 210 are described first as illustrative in nature, and many additional configurations can be conceived by those skilled in the art based on this description.

[0082] Reference Figure 6 The diagram illustrates a cross-sectional view of several microsensors having a multilayer structure including selectively exposed sensing layers according to an embodiment. Several microsensors 210 of the type described below (e.g., capacitive sensors, quartz crystal microbalance (QCM) sensors, or microresonator sensors) can be disposed within a process chamber. For example, a first microsensor 212 and a second microsensor 214 can be mounted on a process chamber 114 or a mounting surface 602 of a wafer substrate 202. The first microsensor 212 and the second microsensor 214 can be adjacent to each other (e.g., arranged side-by-side), and each microsensor can include one or more sensing layers 604 and one or more mask layers 606. Furthermore, the sensing layers 604 of the first microsensor 212 and the second microsensor 214 can be selectively exposed, such that the sensing layer 604 of the first microsensor 212 is exposed to the surrounding environment (e.g., chamber volume 406) when the sensing layer 604 of the second microsensor 214 is shielded by the mask layer 606. Similarly, when the sensing layer 604 of the first microsensor 212 is covered by the mask layer 606, the sensing layer 604 of the second microsensor 214 can be exposed to the surrounding environment.

[0083] To achieve a selectively exposed sensor structure, each microsensor may include one or more pillars of stacked and alternating materials. For example, the first microsensor 212 may have an initial configuration including an exposed sensing layer 608 stacked on a first mask layer 610. Similarly, the first mask layer 610 may be stacked on the first sensing layer 612. The exposed sensing layer 608 may be open to the surrounding environment (e.g., chamber volume) to sense and monitor wafer fabrication processes while the first sensor layer 612 is protected by the first mask layer 610.

[0084] The second microsensor 214 may include a structure similar to that of the first microsensor 212. For example, the second microsensor 214 may have a second mask layer 614 on top of the second sensing layer 616. However, in the initial configuration, the second mask layer 614 may be open to the surrounding environment, thereby protecting the second sensing layer 616 from the wafer fabrication process monitored by the exposed sensing layer 608 of the first microsensor 212. As described below, when the first sensing layer 612 reaches the end of its service life, the second mask layer 614 may be removed to expose the second sensing layer 616. Therefore, the sensing capability of the wafer processing apparatus can be updated and extended, and the second sensing layer 616 can be exposed to monitor the surrounding environment during a subsequent series of wafer processing cycles.

[0085] In embodiments, the alternating mask layers 606 of the first microsensor 212 or the second microsensor 214 may comprise different materials. More specifically, the materials forming the mask layers 606 may be affected by etching actions of different processes. As an example, the first mask layer 610 disposed beneath the exposed sensing layer 608 in the initial configuration may be formed of a first mask material, and the second mask layer 614, which may be exposed to the surrounding environment during the initial configuration, may be formed of a second mask material. The first mask material may be susceptible to etching by an etchant within the chamber volume, and the second mask material may be less susceptible to etching by the same etchant, and vice versa. Therefore, when the second mask layer 614 is etched to expose the underlying second sensing layer 616, the etchant used may not remove the first mask layer 610, and thus the underlying first sensing layer 612 of the first microsensor 212 can remain intact and protected while the second sensing layer 616 monitors the wafer fabrication process.

[0086] Each microsensor's sensing layer 604 can be separated from each other by one or more mask layers 606. For example, a first mask layer 610 can separate the exposed sensing layer 608 of the first microsensor 212 from the first sensing layer 612. That is, the first mask layer 606 can be between the exposed sensing layer 608 and the first sensing layer 612. Similarly, an intermediate mask layer 618 can be disposed between the exposed sensing layers 608 in the first sensing layer 612. For example, the intermediate mask layer 618 can be below or above the first mask layer 610, as shown. In other words, two or more mask layers of a microsensor can separate the two sensing layers of a microsensor. Furthermore, the mask layers of the same microsensor can include dissimilar materials. For example, the intermediate mask layer 618 can be formed of a different material that is susceptible to etchants different from those of the first mask layer 610. Therefore, the mask layers 606 of each microsensor can be formed of different materials, allowing the different materials to be selectively etched by a predetermined etchant to expose the underlying structure as needed.

[0087] Figure 6 The illustrated multilayer structure may include a sensing layer 604 representing a single microsensor or a portion of a microsensor. More specifically, the first microsensor 212 may include a first conductor and a second conductor (such conductors are referred to below). Figure 9 (As described below) Several stacked and vertically offset capacitive microsensors. Alternatively, the first microsensor 212 can be considered as a single capacitive microsensor, and thus the elongated conductor of the capacitive microsensor as described below can be formed with a multilayer structure comprising several vertically separated sensing layers 604 insulated from each other by an intermediate mask layer 606.

[0088] When a microsensor comprises a multilayered structure, etching the various layers can alter the microsensor's parameters. For example, when the sensor itself is layered, the removal of layers may change the sensor's capacitance. Therefore, when the capacitance changes, the sensor can be recalibrated to adjust for the etching process. That is, the sensor can be recalibrated to adjust the new substrate capacitance to accurately sense the wafer fabrication process.

[0089] Reference Figure 7 The diagram shows a cross-sectional view of several microsensors having a cover mask layer 702 over a selectively exposed sensing layer 604, according to an embodiment. The microsensors may be arranged side-by-side on the mounting surface 602. The leftmost microsensor may include the exposed sensing layer 608 in its initial configuration. In contrast, other microsensors (e.g., first microsensor 212 and second microsensor 214) may include corresponding sensing layers 604 and mask layers 606. For example, first microsensor 212 may include a first mask layer 610 over the first sensing layer 612. Similarly, second microsensor 214 may include a second mask layer 614 over the second sensing layer 616.

[0090] As shown in the figure, the corresponding mask layer 606 for each microsensor can be part of a cover mask layer 702. More specifically, a continuous mask coating can be applied to the respective sensor probe to protect the covered sensing layer 604 while the exposed sensing layer 608 monitors the surrounding environment during initial configuration. The cover mask layer 702 can resist etchants used during wafer fabrication processes by the exposed sensing layer 608. As described below, when the exposed sensing layer 608 reaches the end of its lifespan, another etchant (which the cover mask layer 702 is susceptible to) can be used, and this other etchant can reduce the thickness of the cover mask layer 702, thereby allowing the mask material to be removed to expose adjacent microsensors, such as the first microsensor 212.

[0091] The overlay mask layer 702 may include a layer profile with variable thickness, thereby allowing the underlying microsensor 210 to be sequentially exposed by the etchant based on the corresponding thickness of the portion of the overlay mask layer 702 covering the microsensor. For example, as shown, the overlay mask layer 702 may have a wedge-shaped layer profile, such that the first mask layer 610 over the first sensing layer 612 has a first thickness, and the second mask layer 614 over the second sensing layer 616 has a second thickness different from the first thickness. That is, the first thickness may be less than the second thickness, and thus removing the overlay mask layer 702 at a uniform rate will expose the first sensing layer 612 before the second sensing layer 616. The layer profile of the overlay mask layer 702 may include any profile with variable thickness. For example, the layer profile may be stepped, parabolic, etc.

[0092] Reference Figure 8 A cross-sectional view is shown of several microsensors having mask layers 606 of different materials over a selectively exposed sensing layer 604, according to an embodiment. The array of microsensors can be arranged on a mounting surface 602. Each group of microsensors may include a corresponding sensing layer 604 covered by a corresponding mask layer 606. For example, a first group of microsensors 212 may include a corresponding first mask layer 610 over a corresponding first sensing layer 612 (hidden). Similarly, a second group of microsensors 214 may include a corresponding second mask layer 614 over a corresponding second sensing layer 616 (hidden). At any time during the wafer fabrication process, a group of microsensors may include a corresponding exposed sensing layer 608. Thus, the exposed sensing layer 608 can monitor the wafer fabrication process (e.g., it may be etched) while the sensing layers 604 of the other groups of microsensors remain protected under the corresponding mask layers 606.

[0093] The corresponding mask layer 606 for each group of microsensors can be formed from different materials that are susceptible to etching by different etchants. Therefore, when another group of exposed sensing layers 608 has been used and / or has reached the end of its service life, the mask layer 606 of each group can be selectively removed to expose the underlying sensing layer 604.

[0094] In this embodiment, each set of microsensors is electrically connected to a corresponding electrical bus 802. Therefore, these sets of microsensors can be sampled individually to detect changes in their parameters, and thus measure and monitor the wafer fabrication process.

[0095] The above sensor solutions can be combined into a hybrid sensor configuration. For example, regarding... Figure 6 The multilayer sensor structure described herein may include structures with variable thickness (such as...) Figure 7The top mask (shown in the outline of the overlay mask layer 702) can be used to sequentially expose the sensing layers 604 of the first set of microsensors by etching the top mask of variable thickness, and then the subsequent sensing layers 604 of the microsensors can be exposed by removing the intermediate mask layer 618 between the vertically offset sensing layers 604 of the stacked structure.

[0096] Reference Figure 9 The diagram illustrates a perspective view of a microsensor in a wafer processing system according to an embodiment. Microsensor 210 may include a capacitive microsensor with capacitance, and the capacitance of microsensor 210 may change in response to a wafer fabrication process performed by wafer processing tool 102. Microsensor 210 may employ two or more electrodes connected to measurement circuitry. For example, microsensor 210 may have a pair of conductors in a sensing layer, the pair of conductors including a first conductor 902 separated from a second conductor 904 by a dielectric gap. The first conductor 902 and / or the second conductor 904 may be charged. For example, one or more electrodes may be directly connected to drive and sense signals from measurement circuitry of electronic circuitry 218. In an embodiment, one of the electrodes is connected to ground potential.

[0097] The first conductor 902 and the second conductor 904 can be formed of conductive materials, such as polysilicon, aluminum, tungsten, etc. The conductors can be formed on substrate 906 or otherwise mounted on substrate 606. Substrate 906 can be part of the wafer substrate 202 of the particle monitoring device 200. Alternatively, substrate 906 can be mounted on wafer processing tool 102. Substrate 906 can be a silicon wafer substrate, an organic material, a glass cover substrate, or another solid dielectric substrate (e.g., alumina, quartz, silicon dioxide, etc.).

[0098] Each conductor may include a plurality of finger-shaped conductors extending from the conductive pad 908 along a corresponding plane. For example, the first conductor 902 may include a plurality of first elongated conductors 910, and the second elongated conductor 912 may include a plurality of second elongated conductors 912. In an embodiment, the first elongated conductors 910 and the second elongated conductors 912 are interleaved. More specifically, the elongated conductors may interlock or mesh with each other in the same plane to form a capacitance between the finger-shaped structures. Signals can be transported in and out of the elongated conductors via the conductive pad 908. Therefore, the microsensor 210 may include a capacitor with a planar configuration.

[0099] The microsensor 210 can be designed to maximize sensitivity. For example, the electrodes of the microsensor 210 can be formed in a small size and separated by a small space. This size scaling allows for high sensitivity and high effective area density by fabricating the sensor individually, while maintaining overall sensitivity to smaller particles and enabling more discrete particle detection. As an example, each elongated conductor can be separated by a dielectric gap distance of less than 3 micrometers. In embodiments, the dielectric gap distance can be in the range of 50-100 nm. Therefore, the microsensor 210 can detect small perturbations in the dielectric properties between the electrodes. The design of the monitoring and control electronics 218 can also be manipulated to adjust the sensitivity. Thus, the typical detection range of the microsensor 210 can be from low nanofarads to tens of picofarads, and the detection resolution can be on the order of microfarads.

[0100] Reference Figure 10 The diagram illustrates a perspective view of a microsensor in a wafer processing system according to an embodiment. The microsensor 210 may include a coating 1002 on one or more conductors, either a first conductor 902 or a second conductor 904. For example, the coating 1002 may be applied over an area of ​​a conductor that has been patterned into a planar interleaved capacitor. The coating 1002 may be an organic material or a dielectric material. More specifically, the coating 1002 may include a material selected for reaction with a wafer fabrication process. For example, the coating 1002 may include a target material for an etching process. In this embodiment, the coating 1002 includes a dielectric material, such as silicon oxide or silicon nitride. Therefore, a portion of the coating 1002 may be removed when an etching process is performed by the wafer processing tool 102.

[0101] In this embodiment, coating 1002 forms part of the mask layer of microsensor 210, and conductors 902 and 904 form part of the sensing layer of microsensor 210. The sensor layer may also be multilayered and include the intermediate mask layer as described above.

[0102] Reference Figure 11 This illustrates a wafer processing system according to an embodiment. Figure 10 A cross-sectional view of the microsensor taken near line segment AA. The microsensor 210 includes a pair of conductors 1102 on a substrate 906. For example, the pair of conductors 1102 may include a first elongated conductor 910 of a first conductor 902 and a second elongated conductor 912 of a second conductor 904. As described above, the pair of conductors 1102 may be at least partially covered by a coating 1002. The coating 1002 may be as follows: Figure 10The coating shown is a cover coating. More specifically, coating 1002 may include a filler portion 1104 transverse to the interlaced conductors (i.e., filling the dielectric gap) and an outer coating portion 1106 stacked over the top surface of the conductors. Coating 1002 may have a layered structure; for example, filler 1104 may be a first layer formed of a first material (e.g., a hard dielectric (e.g., an oxide or nitride)) and outer coating 1106 may be a second layer formed of a second material (e.g., an organic material). It should be understood that any portion of coating 1002 is optional. For example, in one embodiment, coating 1002 includes filler 1104 transverse to the conductors, and coating 1002 does not include outer coating 1106, thereby exposing the top surface of the conductors. Alternatively, coating 1002 may include outer coating 1106 over the conductors, and coating 1002 may not include filler 1104, thereby creating voids in the dielectric gaps transverse to the conductors. Other embodiments of coating 1002 may be used. For example, coating 1002 may be conformal, such that a thin conformal coating (e.g., 2 nanometers thick) is stacked on the top and side surfaces of the conductor and substrate 906. The width or height of the elongated conductor may be greater than the thickness of conformal coating 1002 (e.g., 3 micrometers), and thus coating 1002 may cover the entire surface of microsensor 210, and at least a portion of the dielectric gap between a pair of conductors 1102 may be unfilled.

[0103] Depositing material 1108 onto any part of microsensor 210 may cause a change in the capacitance of microsensor 210. For example, depositing material 1108 onto... Figure 9 The interlaced finger-like structures shown or Figure 10 The capacitance in the coating 1002 shown can be changed by altering the electric field between a pair of conductors 1102.

[0104] In this embodiment, the material 1108 deposited on the microsensor 210 is a gas. Therefore, the microsensor 210 may include several surface area-enhancing structures. For example, the surface area-enhancing structures may include fibers or pores 1110 designed to trap or absorb gas. For example, the coating 1002 may include a material with a predetermined porosity (e.g., porous oxynitride) to absorb gas like a sponge within the process chamber 114. When gas is absorbed through the pores 1110, the gas can alter the dielectric constant of the coating 1002 (e.g., by increasing the dielectric constant relative to the bulk material of the pores 1110), and the capacitance may change.

[0105] Removing material from microsensor 210 may cause a change in the capacitance of microsensor 210. For example, removing material 1108 from the interlaced finger structure or coating 1002 can change the capacitance by altering the electric field.

[0106] The capacitance change caused by the deposition or removal of material 1108 can be sensed to determine the amount or rate of deposition. For example, the capacitance change can be directly correlated with the amount of material 1108 added or removed. Furthermore, when capacitance can be monitored in real time, the etching rate (e.g., angstroms per minute) can be calculated. Preliminary data indicate that the capacitance change of microsensor 210 can be measured to detect the presence of particles on microsensor 210. Furthermore, several microsensors 210 can be reused to detect relatively large particles. Similarly, combined microsensors 210 can be used to determine particle size.

[0107] The materials for conductors 902 and 904, substrate 906, and coating 1002 can be selected based on the process monitored or controlled using microsensor 210. For example, one or more structures in the configuration may not be affected by the etch process being monitored. For instance, coating 1002 may be designed to be removed by the etch process, and substrate 906 may be designed to be unaffected by the etch process. Similarly, coating 1002 may be removed by the process, and elongated conductors may not be removed by the process.

[0108] The geometry of the microsensor 210 can also be designed to correspond to the process being monitored or controlled. For example, when the process involves material deposition, the finger-like structures can be placed as close to each other as possible to ensure that a detectable change in capacitance occurs when material 1108 is deposited on or between conductors. The thickness of the conductors can also be varied. For example, in contrast to a planar structure, the interlaced, elongated finger-like conductors can be thickened to make the structure more like a parallel plate structure.

[0109] Reference Figure 12 This diagram illustrates a transistor sensor type microsensor in a wafer processing system according to an embodiment. In this embodiment, one or more microsensors 210 of the wafer processing apparatus include a transistor sensor 1200. The transistor sensor 1200 may form part of the sensing layer of the microsensor 210. The transistor sensor 1200 may include one or more transistors, such as a MOSFET 1202. The MOSFET 1202 may include a source 1204, a drain 1206, and a gate 1208. The transistor sensor 1200 may also include a collector 1210 that receives or emits material 1108 during the wafer fabrication process. The collector 1210 may be physically separate from the MOSFET 1202; however, the sub-components may be electrically connected to each other. For example, the collector 1210 may be electrically connected to the gate 1208 of the MOSFET 1202 via a trace 1212. Therefore, even when the collector 1210 is in a predetermined position spaced apart from the MOSFET 1202, the MOSFET 1202 can be configured to detect whether the material 1108 has landed on or evaporated from the collector 1210.

[0110] Collector 1210 may be designed and configured to receive material 1108. For example, the typical size of material 1108 particles may range from 45 nanometers to 1 micrometer, and therefore collector 1210 may include an outer profile with an outer edge having a diameter of at least 1 micrometer. When viewed in a downward direction, the shape of the outer edge may be circular, rectangular, or any other shape. Furthermore, collector 1210 may be flat, i.e., it may have a planar sensor surface, or collector 1210 may have a tapered sensor surface. In embodiments, collector 1210 is not a separate structure from MOSFET 1202, but rather incorporated into MOSFET 1202. For example, collector 1210 may be a collection region on the gate 1208 of MOSFET 1202.

[0111] Similar to the microresonator sensor 1300 described below, the collector 1210 of the transistor sensor 1200 may include a sensor surface configured to mimic the surface of the wafer 402. For example, the transistor sensor 1200 may be located close to the wafer 402 (e.g., on the holding surface 412), and the sensor surface may be oriented to face a forward direction parallel to the direction facing the wafer surface. The collector 1210 may include a multilayer structure, such as a base layer and a top layer having the same or different materials.

[0112] In this embodiment, the parameters of the transistor sensor 1200 correspond to the MOSFET 1202. More specifically, the parameters of the transistor sensor 1200 may be the threshold voltage of the MOSFET 1202 measured across the gate 1208. The threshold voltage may directly correspond to the presence or absence of material 1108 on the collector 1210. For example, the threshold voltage may have a first value when a first amount of material 1108 is on the collector 1210, and a second value (different from the first value) when a second amount of material 1108 is on the collector 1210. Therefore, the amount of material 1108 collected or emitted from the sensor surface of the collector 1210 can be determined based on the threshold voltage of the transistor sensor 1200. The processor 508 may be configured to detect changes in the threshold voltage, and thus, upon detecting a change in the threshold voltage, the wafer processing tool 102 may indicate that the change is an amount of particle detection or material 1108 deposition or removal. Threshold voltages can be recorded over time to determine the actual deposition rate or removal rate of material 1108 on wafer 402.

[0113] Reference Figure 13This diagram illustrates a microsensor of a microresonator type according to an embodiment of a wafer processing system. In this embodiment, one or more microsensors of the wafer processing tool 102 include a microresonator sensor 1300. The microresonator sensor 1300 may form part of the sensing layer of the microsensor 210. The microresonator sensor 1300 may be a suitable resonant mass sensor (e.g., a quartz crystal microbalance (QCM), surface acoustic wave (SAW), or thin-film bulk acoustic resonator (FBAR)) that quantifies the cumulative mass 1302 of airborne particles deposited on its surface. For simplicity and ease of understanding, the complexity and variety of the microresonator sensor 1300 are not described herein. One or more microresonator sensors 1300 may be distributed at predetermined locations on the particle monitoring device 200 or the wafer processing tool 102. Each microresonator sensor 1300 may have a characteristic frequency, such as a resonant frequency, as known in the art. For example, without detailed description, the microresonator sensor 1300 may be represented by a simple mass spring system. The characteristic frequency of the microresonator sensor 1300 can be inversely proportional to the mass 1302 of the microresonator system. For example, the characteristic frequency can be proportional to the sqrt(k / M) of the microresonator sensor 1300, where “M” corresponds to the mass 1302 and “k” corresponds to the scaling constant of the microresonator sensor 1300. Therefore, it should be recognized that the characteristic frequency shifts when the microresonator sensor 1300 receives or delivers material 1108 (e.g., during a wafer fabrication process). For example, when material 1108 (e.g., semiconductor material) is deposited on or removed from the sensor surface of the microresonator sensor 1300 within the process chamber 114 of the wafer processing tool 102, the mass 1302 of the microresonator sensor 1300 changes, and thus the characteristic frequency shifts.

[0114] In this embodiment, the sensor surface includes material 1108. More specifically, the sensor surface may be formed of the same semiconductor material 1108 as the material 1108 deposited on or removed from wafer 402 during the wafer fabrication process. For example, when the wafer fabrication process is a deposition process that deposits silicon onto silicon wafer 402, the sensor surface may include silicon to ensure that the deposited material 1108 interacts with the sensor surface in a manner similar to its interaction with wafer 402. Similarly, when the wafer fabrication process is an etching process that removes silicon from silicon wafer 402, the sensor surface may include silicon to ensure that the material 1108 is etched from the sensor surface at a rate similar to the rate at which silicon is removed from wafer 402. Thus, the sensor surface can mimic the surface of wafer 402 to measure the actual deposition or removal rates occurring simultaneously on wafer 402 during the wafer fabrication process.

[0115] Reference Figure 14 This diagram illustrates a microsensor of an optical sensor type according to an embodiment of a wafer processing system. In this embodiment, one or more microsensors of the wafer processing tool 102 include an optical sensor 1400. The optical sensor 1400 may form part of the sensing layer of the microsensor 210. The optical sensor 1400 may be a micro-optomechanical system (MOEMS) known in the art, and the optical sensor 1400 may be formed directly on a substrate using known semiconductor processing operations. For simplicity and ease of understanding, the complexity and diversity of MOEMS are not described herein. The optical sensor 1400 may include a plurality of micromirrors or lenses distributed on a sensor surface (not shown) of the substrate. Without further description, the optical sensor 1400 may include an optical path 1402 emanating from a light source 1404. The optical path 1402 may be between the light source 1404 and a photodetector 1406. In this embodiment, the parameters of the optical sensor 1400 correspond to whether light is received from the light source 1404 at the photodetector 1406. For example, parameters can be changed in response to material 1108 interfering with optical path 1402. That is, parameters can be changed when particles of material 1108 pass through or remain in optical path 1402 and block light between light source 1404 and photodetector 1406. In an embodiment, when particles pass through optical sensor 1400, light from light source 1404 is reflected to another photodetector 1406 along a different optical path 1402. Detection of the reflected light by the other photodetector 1406 can cause a change in parameters of optical sensor 1400. For example, the parameter could be the output voltage of optical sensor 1400 corresponding to light detection. Processor 508 can be configured to detect changes in output voltage, and thus, upon detection of a change in output voltage and / or when interference in optical path 1402 is detected, wafer processing tool 102 can instruct the deposition or removal of material 1108 on the sensor surface on the substrate, and thus the amount and / or rate of deposition / removal can be measured and monitored in real time.

[0116] It should be understood that, since the aforementioned microsensor types operate based on electrical parameters independent of external pressure, the particle monitoring device 200 or wafer processing tool 102, which incorporates one or more of the following microsensors 210: microresonator sensor 1300, transistor sensor 1200, or optical sensor 1400, can operate under any pressure conditions (including vacuum conditions). Similarly, the microsensors can operate regardless of the gas concentration in the chamber volume 406 (including under plasma-free conditions).

[0117] The particle monitoring device 200 or wafer processing tool 102 may include any combination of the aforementioned sensors. For example, the microsensors 210 may be grouped as a set of thousands of microsensors on the underlying substrate. More specifically, the microsensors 210 may be linked into groups, and the substrate capacitance can be selected by choosing different numbers of capacitors from said groups. This selection may be controlled by the processor 508. In embodiments, the processor 508 monitors different types of sensors. For example, microsensors 210 configured to detect material deposition and microsensors 210 configured to detect material etching may be monitored simultaneously or at different stages of the wafer fabrication process to collect additional data and form a multi-purpose sensor. Similarly, analog-to-digital capacitance measurement circuitry may be used to monitor the microsensors 210 at different frequencies to obtain additional information. For example, the measurement circuitry may probe one or more microsensors 210 at low frequencies, high frequencies, or by scanning a wide range of frequencies to collect additional information.

[0118] A wafer processing tool 102 with microsensors mounted, for example, on a process chamber 114, can be used to monitor or control the wafer manufacturing process. Monitoring may include updating or exposing the sensing layer of an active microsensor when it reaches the end of its lifespan. Although not limiting, several methods for performing such monitoring and control are described below. For the sake of brevity, the operations in the methods described below may refer to the monitoring of a microsensor with capacitance parameters; however, the methods may be applicable to include other microsensor types, such as those described above.

[0119] Reference Figure 15 The diagram illustrates a flowchart of the operation of a method for updating a microsensor of a wafer processing apparatus according to an embodiment. Figures 16A to 16C It shows Figure 15 The operation of the method described herein, and therefore the following section on... Figure 15 as well as Figures 16A to 16C Describe them together.

[0120] Wafer processing equipment may include the above references Figure 7 The selectively exposed microsensor described above. At operation 1502, the wafer fabrication process can be initiated in process chamber 114. (See reference...) Figure 16A The wafer 402 can be loaded into a chamber volume containing several microsensors 210, and an etching process can be initiated. For example... Figure 16A As shown, the leftmost microsensor 210 can be exposed in the initial configuration. That is, when the wafer fabrication process begins, the leftmost microsensor 210 can be exposed to the chamber volume 406.

[0121] At operation 1504, the wafer fabrication process may include etching to remove material from wafer 402. The leftmost microsensor 210 may be an exposed microsensor having a sensing layer comprising a material similar to that of the wafer. Therefore, the exposed sensor surface on the exposed sensing layer of the exposed microsensor can be etched using an etchant from the wafer fabrication process. Thus, the exposed microsensor can sense and monitor the removal of material during the wafer fabrication process.

[0122] The first microsensor 212, which may be adjacent to the exposed microsensor, may include a first mask layer 610 exposed to the chamber volume 406. The first mask layer 610 may be unaffected by the etchant used during the wafer fabrication process. Therefore, the first sensing layer 612 beneath the first mask layer 610 may be protected from the etching process during a stage of the wafer fabrication process.

[0123] Exposed microsensors can be etched until the sensor reaches the end of its lifespan. The exposed microsensors can be monitored to determine when the surface morphology of the exposed sensing surface changes in a way that causes the sensor's sensitivity to exceed permissible limits (indicating the end of its lifespan). The steps for testing exposed microsensors for end-of-life can include electrical diagnostic procedures. For example, an electrical input can be delivered to the exposed microsensor via a corresponding electrical trace 216, and the output from the exposed microsensor can be measured. The output of the exposed microsensor can be responsive to the input signal and can correspond to parameters of the microsensor. For example, the output can correspond to the sensitivity of the exposed microsensor. In this case, the sensitivity can vary based on the surface morphology, and therefore, when the output is a predetermined value, it can be determined that the exposed microsensor is at the end of its lifespan. In embodiments, the exposed microsensor may be at the end of its lifespan when the microsensor's parameters are presented in a predetermined manner. For example, when the exposed microsensor is a capacitive microsensor, it may be at the end of its lifespan when the capacitance of the microsensor no longer changes linearly with respect to the wafer fabrication process.

[0124] When it is necessary to decommission an exposed microsensor for replacement, another microsensor can be selectively exposed. At operation 1506, the first mask layer 610, shown as adjacent to the exposed microsensor, can be peeled off to expose the first sensor surface on the first sensing layer 612 of the first microsensor 212. Various techniques can be used to perform the peeling of the first mask layer 610. For example, the mask layer can be peeled off by eroding a chemical substance of the first mask layer 610. The formulation of the chemical substance can depend on the mask material. For example, the overlay mask layer 702 containing the first mask layer 610 may include oxides or nitrides, and the peeling chemical substance can be appropriately formulated to remove oxide and nitride materials.

[0125] In this embodiment, the overlay mask layer 702 is formed of a material different from the material that is designed to be removed by the wafer fabrication process. For example, the wafer fabrication process may be designed to remove oxide materials, and therefore the overlay mask layer 702 may be formed of a protective nitride layer. Thus, the target material of the wafer fabrication process may not be affected by the etchant used to strip the first mask layer 610.

[0126] Alternative techniques can be used to peel off the mask layer covering the sensor surface. For example, thermal techniques (i.e., elevated temperatures) that cause the mask layer to decompose and / or dissolve can be used to peel off the mask layer. In embodiments, other agents can be used to decompose and / or dissolve the mask layer. For example, water can be applied to mask layer 702 to dissolve and peel off mask layer 702, thereby exposing the underlying sensing layer.

[0127] like Figure 16B As shown, the cover mask layer 702 can be retracted to expose the first microsensor 212 to the right of the decommissioned leftmost microsensor 210. In an embodiment, the leftmost microsensor 210 can be removed from use by interrupting any electrical sampling of the sensor (i.e., by electrically disconnecting the sensor). The removal rate of the cover mask layer 702 can vary for various reasons (e.g., variations in the etching process), and therefore the step of detecting when the cover mask layer 702 has retracted far enough to expose the first microsensor 212 but not far enough to expose the second sensing layer 616 of the second microsensor 214 can provide useful information. For this purpose, the first microsensor 212 and the second microsensor 214 can be monitored simultaneously during the mask layer stripping. For example, parameters of the microsensors (e.g., capacitance) can be sensed. The capacitance can vary based on the thickness and / or presence of the mask layer on the sensing layer of the microsensor, and thus it can be determined when the mask layer has been removed from the first sensing layer 612 but still remains on the second sensing layer 616. This diagnostic can be used to trigger the next operation in the wafer manufacturing process (such as the continuation of the wafer etching process).

[0128] At operation 1508, the exposed sensor surface on the first sensing layer 612 can be etched during the wafer fabrication process. That is, the wafer fabrication process may include etching of the wafer, and the first microsensor 212 can actively sense the process. This can continue until the first microsensor 212 reaches the end of its service life, which can be determined as described above.

[0129] At operation 1510, the second mask layer 614 of the second microsensor 214 can be peeled off to expose the second sensor surface on the second sensing layer 616. Any of the peeling techniques described above in the glass technology can be used to selectively expose the second sensor surface. Therefore, the second microsensor 214, protected during a previous segment of the wafer fabrication process, can be exposed during a subsequent segment of the wafer fabrication process to become an active sensor. The first microsensor 212, which may be at the end of its lifespan, can be decommissioned during a subsequent segment.

[0130] At operation 1512, the exposed sensor surface on the second sensing layer 616 can be etched during the wafer fabrication process. That is, the wafer fabrication process may include etching of the wafer, and the second microsensor 214 can actively sense the process. This can continue until the second microsensor 214 reaches the end of its service life, which can be determined as described above. The above procedure can be repeated to expose additional microsensors to continuously sense the wafer fabrication process over extended time periods (e.g., hundreds of process cycles).

[0131] Reference Figure 17 The diagram illustrates a flowchart of the operation of a method for updating a microsensor of a wafer processing apparatus according to an embodiment. Figures 18A to 18F It shows Figure 17 The operation of the method described, and therefore, in the following text... Figure 17 and Figures 18A to 18F Describe them together.

[0132] Wafer processing equipment may include the above references Figure 6 The aforementioned selectively exposed microsensors. At operation 1702, the wafer fabrication process can be initiated within the process chamber. (See reference...) Figure 18A The first microsensor 212 may include an exposed sensing layer in the initial configuration. In the initial configuration, the second microsensor 214 may include a second mask layer 614 that protects the underlying second sensing layer 616. More specifically, the second mask layer 614 can be used to protect the second sensing layer 616 when the wafer is being processed in a process chamber.

[0133] At operation 1704, the wafer fabrication process may include etching to remove material from the wafer. The exposed sensing layer of the first microsensor 212 may include a material similar to that of the wafer. Therefore, the exposed sensor surface on the exposed sensing layer can be etched using an etchant from the wafer fabrication process. Thus, the exposed sensing layer of the first microsensor 212 can sense and monitor the removal of material. However, the etchant used to remove material from the first sensor surface may not remove material from the second mask layer 614. That is, the second microsensor 214, which may be adjacent to the first microsensor 212, may include a second mask layer 614 exposed to the chamber volume. The second mask layer 614 may be formed of a material dissimilar to the exposed sensing layer, and therefore the second sensing layer 616 beneath the second mask layer 614 may be protected from the etching process during a stage of the wafer fabrication process.

[0134] The exposed sensing layer of the first microsensor 212 can be etched until the sensor reaches the end of its lifespan. When the first microsensor 212 needs to be updated, the second sensing layer 616 of the second microsensor 214 can be selectively exposed.

[0135] Reference Figure 18C At operation 1706, before or after exposing the second sensing layer 616, any residual sensor material of the first sensing layer 612 can be peeled off. For example, any of the peeling techniques described above can be used to remove residual first sensing layer 612.

[0136] At operation 1708, the second sensing layer 616 can be exposed by peeling off the second mask layer 614. Any of the peeling techniques described above can be used to remove the second mask layer 614. The second mask layer 614 may not be affected by the etchant used to process the wafer, and the second mask layer 614 may be susceptible to etching by another etchant that does not erode the wafer. Therefore, the second mask layer 614 can be peeled off without affecting the wafer or the first mask layer 610 exposed to the chamber volume after the removal of the exposed sensing layer 608. More specifically, the second mask layer 614 may be formed of a different material than the first mask layer 610, and therefore the application of the etchant can remove one mask layer without removing the other.

[0137] Reference Figure 18DAt operation 1710, after removing the second mask layer 614 to expose the second sensing layer 616, the first mask layer 610 of the first microsensor 212 can be stripped to expose the intermediate mask layer 618. The intermediate mask layer 618 can be formed on top of the sensing layer 604 below the first microsensor 212. More specifically, the intermediate mask layer 618 can be formed of a material that is not affected by etching by etchants used to process the wafer. For example, the intermediate mask layer 618 can have the same material as the second mask layer 614 that protects the second sensing layer 616 during an earlier stage of the wafer fabrication process. Therefore, the intermediate mask layer 618 will not be etched by etchants while the second sensing layer 616 is monitoring the process.

[0138] Reference Figure 18E At operation 1712, the exposed sensing layer of the second microsensor 214 can be used to sense and monitor the wafer fabrication process. For example, the second sensing layer 616 can monitor the removal of material from the wafer. Simultaneously, the intermediate mask layer 618 can protect the sensing layer beneath the first microsensor 212. The exposed sensing layer of the second microsensor 214 can be etched until the sensor reaches the end of its lifespan.

[0139] Reference Figure 18F When the second microsensor 214 needs to be replaced, the first microsensor 212 can be updated by exposing another sensing layer 604. More specifically, the second sensing layer 616 and the intermediate mask layer 618 can be peeled off from their respective microsensors to expose the sensing layer 604 beneath the first microsensor 212 and the mask layer 606 of the second microsensor 214. Therefore, the stacked structure of the first microsensor 212 and the second microsensor 214 can be etched sequentially to intermittently expose the sensing layers, thus updating the sensing capabilities of the microsensors and the wafer fabrication equipment.

[0140] Reference Figure 19 A block diagram of an exemplary computer system according to an embodiment of a wafer processing system is shown. One or more components of the computer system 104 shown may be used in the electronic circuitry 218 of the wafer processing tool 102. Therefore, the above description regarding... Figure 5 The electronic circuitry 218 discussed may be a subset of the computer system 104. Alternatively, the electronic circuitry 218 may be local to the particle monitoring device 200 or the wafer processing tool 102, and the computer system 104 may be a manufacturing facility host computer with an interface connected to the electronic circuitry 218 of the wafer processing tool 102 and / or the computer. In embodiments, the computer system 104 is coupled to and controls the robot, loading / unloading mechanism 112, process chamber 114, and other components of the wafer processing tool 102. As described above, the computer system 104 may also receive and analyze particle detection or material deposition / removal information provided by the microsensor 210.

[0141] Computer system 104 can be connected (e.g., network connected) to other machines in a local area network (LAN), intranet, extranet, or the Internet. Computer system 104 can operate within the capacity of a server or client machine in a client-to-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. Computer system 104 can be a personal computer (PC), tablet computer, set-top box (STB), personal digital assistant (PDA), cellular phone, network device, server, network router, switch, or bridge, or any machine capable of executing a set of instructions (sequentially or otherwise) specifying actions to be taken by said machine. Furthermore, although only a single machine for computer system 104 is shown, the term "machine" should also be considered as including a collection of machines (e.g., computers) that individually or collectively execute a set (or more) of instructions for performing any or more of the methods described herein.

[0142] Computer system 104 may include a computer program product or software 1902 having instructions stored thereon on a non-transient machine-readable medium, which can be used to program computer system 104 (or other electronic devices) to perform the process according to the embodiments. Machine-readable medium includes any mechanism for storing or transmitting information in a machine-readable (e.g., computer-readable) form. For example, machine-readable (e.g., computer-readable) media include machine-readable (e.g., computer-readable) storage media (e.g., read-only memory (“ROM”), random access memory (“RAM”), disk storage media, optical storage media, flash memory devices, etc.), machine-readable (e.g., computer-readable) transmission media (electrical, optical, acoustic, or other forms of propagated signals (e.g., infrared signals, digital signals, etc.)), etc.

[0143] In an embodiment, the computer system 104 includes a system processor 1904, a main memory 1906 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) (e.g., synchronous DRAM (SDRAM) or bus-type DRAM (RDRAM)), a static memory 1908 (e.g., flash memory, static random access memory (SRAM), etc.), and auxiliary memory (e.g., data storage device 1924), which communicate with each other via a bus 1909.

[0144] System processor 1904 represents one or more general-purpose processing devices, such as microsystem processors, central processing units, etc. More specifically, system processor 1904 may be a Complex Instruction Set Computing (CISC) microsystem processor, a Reduced Instruction Set Computing (RISC) microsystem processor, a Very Long Instruction Word (VLIW) microsystem processor, a system processor implementing other instruction sets, or a system processor implementing a combination of instruction sets. System processor 1904 may also be one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal system processors (DSPs), network system processors, etc. System processor 1904 is configured to execute processing logic 1910 for performing the operations described herein.

[0145] Computer system 104 may further include a system network interface device 1912 for communicating with other devices or machines (e.g., wafer processing tool 102) via network 1914. Computer system 104 may also include a video display unit 1916 (e.g., a liquid crystal display (LCD), a light-emitting diode display (LED), or a cathode ray tube (CRT)), a text and numeric input device 1918 (e.g., a keyboard), a cursor control device 1920 (e.g., a mouse), and a signal generation device 1922 (e.g., a speaker).

[0146] Auxiliary storage may include a data storage device 1924 having a machine-accessible storage medium 1926 (or more specifically, a computer-readable storage medium) thereon storing one or more sets of instructions (e.g., software 1902) embodying any one or more of the methods or functions described herein. Software 1902 may also reside wholly or at least partially within main memory 1906 and / or system processor 1904 during execution by computer system 104, which also constitute machine-readable storage media. Software 1902 may further be transmitted or received on network 1914 via system network interface device 1912.

[0147] Although the machine-accessible storage medium 1926 is shown as a single medium in the exemplary embodiments, the term "machine-readable storage medium" should be considered to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of instructions. The term "machine-readable storage medium" should also be considered to include any medium capable of storing or encoding a set of instructions for machine execution and enabling the machine to perform any or more of the methods described. Therefore, the term "machine-readable storage medium" should be considered to include, but is not limited to, solid-state memory, as well as optical and magnetic media.

[0148] Specific exemplary embodiments have been described in the foregoing description. It should be understood that various modifications may be made to the exemplary embodiments without departing from the scope of the appended claims. Therefore, the description and drawings should be regarded as illustrative rather than restrictive.

Claims

1. A particle monitoring device, comprising: A substrate, the substrate including electronic devices and a support surface; A first microsensor is mounted on the support surface, wherein the first microsensor includes a first sensing layer and a first mask layer above the first sensing layer; as well as A second microsensor, mounted on the support surface, wherein when the first sensing layer is exposed, the second microsensor includes a second sensing layer and a second mask layer above the second sensing layer. The first microsensor and the second microsensor have corresponding parameters, and the first microsensor and the second microsensor include corresponding sensor surfaces on corresponding sensing layers, wherein the corresponding parameters change when material is deposited on or removed from the corresponding sensor surface.

2. The particle monitoring device of claim 1, further comprising an exposure sensing layer, the exposure sensing layer being mounted on the support surface and open to the surrounding environment.

3. The particle monitoring device as described in claim 2, characterized in that, The first mask layer has a first thickness, and the second mask layer has a second thickness, which is different from the first thickness.

4. The particle monitoring device as described in claim 3, characterized in that, The first mask layer and the second mask layer are portions of an overlay mask layer having a layer profile including a variable thickness.

5. The particle monitoring device as described in claim 2, characterized in that, The first mask layer has a first mask material, wherein the second mask layer has a second mask material, and wherein the first mask material is affected by etching by an etchant in the surrounding environment, and the second mask material is not affected by etching by the etchant.

6. The particle monitoring device as described in claim 5, characterized in that, The first microsensor includes the exposure sensing layer, wherein the first mask layer is located between the exposure sensing layer and the first sensing layer.

7. The particle monitoring device of claim 6, further comprising an intermediate mask layer between the exposure sensing layer and the first sensing layer.

8. The particle monitoring device as described in claim 1, characterized in that, The microsensor includes a microsensor, wherein the corresponding parameter is the capacitance of the microsensor, and wherein the capacitance changes when material is deposited on or removed from the corresponding sensor surface.

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