Integrated thermal-tunable QCM monitoring system for advanced semiconductor processes

Abstract

A monitoring system for semiconductor processes includes an oven block that defines an interior space. A QCM sensor assembly includes a quartz crystal configured to be positioned within the interior space. One or more heating rods are configured to heat the interior space of the oven block to create a thermal environment. One or more temperature detectors are positioned in the oven block and configured to measure a temperature of the thermal environment. A temperature controller is connected to the one or more heating rods and the one or more temperature detectors and is configured to control the thermal environment. A frequency analyzer is configured to monitor a frequency of the quartz crystal. A controller is configured to receive and analyze signals from the frequency analyzer and is configured to adjust the thermal environment based on the received and analyzed signals from the frequency analyzer.

Description

INTEGRATED THERMAL-TUNABLE QCM MONITORING SYSTEM FORADVANCED SEMICONDUCTOR PROCESSESCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to, and the benefit of, U.S. Provisional Patent Application Serial No. 63 / 728,000, filed on December 4, 2024. The entire contents of said application are hereby incorporated by reference.TECHNOLOGICAL FIELD

[0002] This invention relates generally to the field of semiconductor manufacturing / processing. More specifically, the following disclosure is directed to a system for precisely controlling the operating temperature of QCM sensors in semiconductor equipment including detecting ampoule depletion using QCM sensors or sensor assemblies to detect volatile precursors that decompose at high temperatures and extending the sensor lifetime by heating the sensor to evaporate accumulated mass-loading materials.BACKGROUND

[0003] In the highly competitive semiconductor industry, where margins are tight and demand for advanced nodes is high, even minor interruptions can lead to significant financial and reputational losses. Detecting ampoule depletion levels during semiconductor processing is critical because the industry demands precision and consistency in every step of fabrication. Processes like Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) rely on a32850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 continuous and controlled supply of precursors to deposit thin films with precise thicknesses and properties. If the precursor in an ampoule is depleted mid-process without detection, it can lead to film non-uniformities, defects, and device failures, compromising the entire wafer batch. This not only affects yield but also increases production costs and wastes valuable materials. Depletion detection ensures process continuity, enabling fabs to operate efficiently and without downtime. It also integrates with automation systems to trigger alerts or switch to backup ampoules, minimizing manual intervention and improving productivity. Overall, ampoule depletion detection is essential for maintaining the precision, safety, and cost-efficiency required in semiconductor manufacturing.

[0004] One of the current solutions to detect ampoule depletion relies on the use of a Quartz Crystal Microbalance (QCM), which is an advanced piezoelectric sensor capable of detecting extremely small mass changes with nanogram-level precision. This technology utilizes the reverse piezoelectric effect, where an applied voltage causes the quartz crystal to oscillate. Accordingly, an alternating electrical signal is applied to a thin quartz disk, which causes the quartz crystal to oscillate at a natural resonant frequency. This frequency is extremely sensitive to additional mass loaded on the crystal surface — even down to nanogram or sub-nanogram levels. As material accumulates, the oscillation slows down in a predictable way, allowing for direct, quantitative analysis of the mass change.

[0005] The theoretical foundation of QCM measurements is the Sauerbrey equation, which establishes a linear relationship between the frequency shift and the change in mass per unit area:Where A / ' is the frequency shift (Hz), f0is the fundamental frequency of the quartz crystal (Hz), 232850556.1PATENTATTORNEY DOCKET NO. 3221419WO01A is the active area of the electrode (cm2), pqis the density of quartz (2.648 g / cm3), pqis the shear modulus of quartz, and Am is the mass change per unit area (g / cm2). Of course, different crystals will exhibit different parameter values.

[0006] Therefore, based on the working principle of QCM, there is no doubt that QCM can provide valuable insight into process stability and offers indirect yet reliable indications of precursor availability and potential ampoule depletion, helping to maintain continuous, consistent, and optimized deposition performance.

[0007] To ensure operational stability, the quartz crystal is securely integrated into the sensor 50, as illustrated in FIGS. 2A and 2B. A sophisticated frequency monitoring technology provides accurate tracking of these frequency changes, enabling reliable and precise mass measurements. Accordingly, ampoule depletion detection can be addressed by strategically installing QCM sensors on the chamber walls or forelines of semiconductor tools. The foreline is a critical location where the temperature remains relatively constant across various process steps. While this thermal stability helps ensure signal consistency and minimizes environmental noise, it significantly reduces the sensor’s ability to respond accurately to temperature-sensitive material behaviors.

[0008] In actual semiconductor processes, many critical mechanisms — such as precursor adsorption, reaction kinetics, decomposition pathways, and material volatility — are highly temperature-dependent. For example, certain precursors may only undergo meaningful reactions at elevated temperatures, and those reactions may not initiate at all in the cooler regions where QCM sensors are typically placed, such as forelines. As a result, under such themial mismatch conditions, the QCM may fail to detect or misinterpret key process phenomena, such as insufficient precursor delivery. This discrepancy between the QCM’s actual operating temperature332850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 and the optimal sensing temperature required for specific applications fundamentally limits its accuracy, sensitivity, and diagnostic value in many advanced process environments.

[0009] In addition, enabling temperature control around the QCM can extend the sensor’s operational life and reduce the need for frequent maintenance. For example, when a QCM sensor is installed in a fixed location such as on a chamber wall or foreline, residual materials from the process may gradually accumulate on the crystal surface over time. This buildup, often caused by continuous exposure to precursors, reaction products, or intermediate species, can interfere with the crystal’s ability to oscillate properly. Once the accumulated mass exceeds a certain threshold, the crystal’s resonance becomes significantly dampened or may even cease entirely, leading to a complete loss of sensor function. If the QCM sensor operates in an environment where temperature can be precisely controlled, this challenge can be effectively addressed. By increasing the local temperature when needed, many of the accumulated materials can be desorbed or evaporated from the crystal surface. This thermal cleaning effect helps prevent long-term buildup, preserving the crystal’s oscillation integrity. Consequently, controlling the temperature around the QCM makes the system far more robust and suitable for continuous, real-time monitoring in demanding semiconductor manufacturing environments.

[0010] Currently, there is a clear lack of effective and widely adopted solutions for precisely controlling the operating temperature of QCM sensors in semiconductor equipment. Traditional QCM sensors are typically mounted on chamber walls or forelines, where the temperature remains relatively stable throughout the process, but differs from the optimal operating temperatures required for QCMs in various specific applications. While this stability reduces signal noise, it creates a fundamental mismatch between the sensor’s thermal environment and the temperature-sensitive nature of many precursor materials, product materials or other432850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 intermediate materials. Critical behaviors such as adsorption, desorption, surface reactions, and thermal decomposition are highly dependent on temperature, and this disconnect significantly limits the QCM’s ability to detect and characterize such processes accurately. At present, no mature or flexible temperature control strategies exist that allow QCMs to be adaptively tuned to match the thermal requirements of different materials or process conditions.

[0011] As a result, conventional QCM systems are less effective or entirely unsuitable for precisely controlling the operating temperature of QCM sensors in semiconductor equipment. This limitation underscores the need for substantial improvements and tailored optimizations to adapt QCM systems for such applications.SUMMARY

[0012] Aspects of the present disclosure are directed to embodiments of a monitoring system for semiconductor processes. In some embodiments, the system includes an oven block configured to couple to one of: (i) a foreline; or (ii) a process chamber and defining an interior space. In some embodiments, the system includes a QCM sensor assembly including a quartz crystal configured to be positioned within the interior space of the oven block. In some embodiments, the system includes one or more heating rods configured to heat the interior space of the oven block to create a thermal environment for the QCM sensor assembly and one or more temperature detectors positioned in the oven block and configured to measure a temperature of the thermal environment. In some embodiments, the system includes a temperature controller in communication with the one or more heating rods and the one or more temperature detectors and configured to control the thermal environment and a frequency analyzer configured to monitor a frequency of the quartz crystal. In some embodiments, the system includes a controller configured532850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 to receive signals from the frequency analyzer. In some embodiments, the thermal environment may be adjusted based on the analysis and interpretation of the received signals from the frequency analyzer.

[0013] In some embodiments of the system, the controller is configured to receive signals from the temperature controller and the thermal environment may be ideally adjusted based on the analysis and interpretation of the received signals from the frequency analyzer and the temperature controller. In some embodiments, the system includes an insulated covering configured to at least partially surround the oven block. In some embodiments of the system, the insulated covering is comprised of a reflective material that is configured to be removably formed at least partially around the oven block. In some embodiments, the system further includes a thermal fuse configured to be positioned in the thermal environment and to interrupt power to the one or more heating rods when the thermal environment exceeds a predefined threshold temperature. In some embodiments of the system, the oven block defines a first opening dimensioned to accept the QCM sensor assembly and a second opening configured to be coupled to one of: (i) the foreline; or (ii) the process chamber. In some embodiments, at least one of the first opening and the second opening includes a flange.

[0014] Aspects of the present disclosure are directed to embodiments of a method of monitoring semiconductor processes. In some embodiments, the method includes structuring an oven block to couple to one of: (i) a foreline; or (ii) a process chamber and defining an interior space. In some embodiments, the method includes structuring a QCM sensor assembly to include a quartz crystal configured to be positioned within the interior space of the oven block. In some embodiments, the method includes heating the interior space of the oven block to create a thermal environment for the QCM sensor assembly, continuously measuring a temperature of the thermal632850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 environment, and continuously monitoring a frequency of the crystal. In some embodiments, the method includes controlling the thermal environment based on the analysis and interpretation of the monitored frequency.

[0015] In some embodiments, the method further includes controlling the thermal environment based on the analysis and interpretation of the monitored frequency and the measured temperature. In some embodiments, the method further includes automatically stopping the heating of the interior space when the temperature of the thermal environment exceeds a predefined threshold temperature. In some embodiments, the method further includes positioning an insulated covering to at least partially surround the oven block. In some embodiments, the method further includes structuring the oven block to define a first opening dimensioned to accept the QCM sensor assembly and a structuring a second opening configured to be coupled to one of: (i) the foreline; or (ii) the process chamber. In some embodiments, the method further includes structuring at least one of the first opening and the second opening to include a flange.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A more particular description of the invention briefly summarized above may be had by reference to the described embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. Thus, for further understanding of the nature and objects of the invention, references can be made to the following detailed description, read in connection with the drawings.

[0017] FIG. 1 A schematically illustrates a perspective view of an embodiment of a732850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 quartz crystal of a QCM sensor positioned between electrodes to generate oscillation of the quartz crystal, according to aspects of the present disclosure.

[0018] FIG. IB illustrated top and bottom plan views of embodiments of the electrodes from FIG. 1 A, according to aspects of the present disclosure.

[0019] FIG. 2A illustrates a perspective view of an embodiment of a QCM sensor assembly, according to aspects of the present disclosure.

[0020] FIG. 2B illustrates an exploded view of the embodiment of FIG. 2A.

[0021] FIG. 2C illustrates an embodiment of a 5-pin leaf spring used in the embodiment of FIG. 2A to maintain reliable electrical and mechanical stability even after extended thermal cycling.

[0022] FIG. 3A schematically illustrates a prior art embodiment of a monitoring system for semiconductor processes.

[0023] FIG. 3B schematically illustrates another prior art embodiment of a monitoring system for semiconductor processes.

[0024] FIG. 4A schematically illustrates an embodiment of a monitoring system for semiconductor processes, according to aspects of the present disclosure.

[0025] FIG. 4B illustrates a perspective view of an embodiment of a system module, according to aspects of the present disclosure.

[0026] FIG. 4C illustrates another perspective view of an embodiment of a system module, according to aspects of the present disclosure.

[0027] FIG. 4D schematically illustrates embodiments of components comprising an embodiment of the controller, according to aspects of the present disclosure.

[0028] FIG. 5A schematically illustrates another embodiment of a monitoring832850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 system for semiconductor processes, according to aspects of the present disclosure.

[0029] FIG. 5B illustrates a perspective view of an embodiment of an insulated covering showing an interior surface, according to aspects of the present disclosure.

[0030] FIG. 5C illustrates a perspective view of an embodiment of the insulated covering showing an exterior surface, according to aspects of the present disclosure.

[0031] FIG. 5D illustrates a perspective view of an embodiment of the insulated covering installed on an oven block, according to aspects of the present disclosure

[0032] FIG. 6A illustrates a perspective view of an embodiment of an oven block, according to aspects of the present disclosure.

[0033] FIG. 6B illustrates an exploded view of a QCM sensor assembly with the embodiment of the oven block of FIG. 6A, according to aspects of the present disclosure.

[0034] FIG. 7A illustrates a perspective view of another embodiment of an oven block, according to aspects of the present disclosure.

[0035] FIG. 7B illustrates an exploded view of a QCM sensor assembly with the embodiment of the oven block of FIG. 7A, according to aspects of the present disclosure.

[0036] FIG. 8A illustrates a perspective view of another embodiment of an oven block, according to aspects of the present disclosure.

[0037] FIG. 8B illustrates an exploded view of a QCM sensor assembly with the embodiment of the oven block of FIG. 8A, according to aspects of the present disclosure.

[0038] FIG. 9A illustrates a wiring diagram of an embodiment of a temperature controller, according to aspects of the present disclosure.

[0039] FIG. 9B illustrates a perspective view of an embodiment of a temperature controller, according to aspects of the present disclosure.

[0040] FIG. 10 graphically illustrates data for a real-time monitoring of the932850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 temperature control and QCM sensor fundamental frequency response, according to aspects of the present disclosure.DETAILED DESCRIPTION

[0041] The following discussion relates to various embodiments of systems and methods for ampoule depletion detection of volatile precursors by using QCM sensors. It will be understood that the herein described versions are examples that embody certain inventive concepts as detailed herein. To that end, other variations and modifications will be readily apparent to those of sufficient skill. In addition, certain terms are used throughout this discussion in order to provide a suitable frame of reference with regard to the accompanying drawings. These terms such as “upper”, “lower”, “forward”, “rearward”, “interior”, “exterior”, “front”, “back”, “top”, “bottom”, “inner”, “outer”, “first”, “second”, and the like are not intended to limit these concepts, except where so specifically indicated. The terms “about” or “approximately” as used herein may refer to a range of 80%-120% of the claimed or disclosed value. With regard to the drawings, their purpose is to depict salient features of the systems and methods for ampoule depletion detection of volatile precursors by using QCM sensors and are not specifically provided to scale.

[0042] Figure 1A illustrates an embodiment of a QCM sensor 10. In some embodiments, the QCM sensor 10 includes a quartz crystal 12 and a plurality of electrodes 14 in contact with the quartz crystal 12. In some embodiments, the quartz crystal 12 is a least partially positioned between two electrodes 14a, 14b. Tn some embodiments, the front face of the crystal fully covered by the electrode 14, providing uniform electrical contact across the surface of the quartz crystal 12. In some embodiments, the electrodes 14 are comprised of a metal. The quartz crystal 12 as shown in Figure 1 A, is a functional material that vibrates in response to an alternating1032850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 voltage (denoted by "v") applied by a voltage source 20 across the electrodes 14, 14a, 14b.

[0043] Referring to FIGS. IB, an embodiment of the two electrodes 14a, 14b is shown. In some embodiments, the two electrodes 14a, 14b are identical to each other. In some embodiments, the two electrodes 14a, 14b are not identical and include different electrode patterns. In some embodiments a first 14a of the two electrodes defines a first electrode pattern and the second 14b of the two electrodes includes a second electrode pattern that is different than the first electrode pattern. In some embodiments, the first electrode 14a includes an outer surface or first surface 16 that faces the mass loading or in other words, faces away from the quartz crystal 12. In some embodiments, the second electrode pattern comprises the back surface 18 of the electrode 14b and is strategically shaped to excite stable oscillations and ensure consistent piezoelectric performance of the QCM sensor 10. In some embodiments, the quartz crystal 12 comprises a diameter of about 14mm. When the alternating voltage is applied by the voltage source 20 across the electrodes 14a, 14b, the quartz crystal 12 begins to oscillate at a specific resonance frequency. This frequency is influenced by both the intrinsic thickness of the quartz crystal 12 and the mass of any material present on its surface. As molecules or thin films accumulate on the crystal surface, the added mass causes a measurable drop in oscillation frequency, allowing for precise quantification of the deposition process.

[0044] Referring to Figs. 2A-B, an embodiment of a QCM sensor assembly 50 is shown including a sensor housing or a sensor body 52 that is structured to at least partially surround and / or support various components of the QCM sensor assembly 50. In some embodiments, the QCM sensor assembly 50 includes a retainer assembly 54 and a holder 56. In some embodiments, the retainer assembly 54 is configured to cooperate with the holder 56 to retain the QCM sensor 10. In some embodiments, the holder 56 defines an opening 57 that is configured1132850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 to expose the first surface 16 to an external or chamber environment. In some embodiments, one or more inputs 44 and a flange 46 or mount are connected to the sensor assembly 50. In some embodiments, the one or more inputs 44 may include an energy input. In some embodiments, the flange 46 or mount that is configured to couple the QCM sensor assembly 50 to a reaction chamber or process chamber 60 or a foreline 70. In some embodiments, the retainer assembly 54 includes a leaf spring 55 that connects to the back surface 18 of the second electrode 14b. However, in some embodiments, the retainer assembly 54 includes a 5-pin leaf spring 53 configuration as shown in FIG. 2C, having five (5) leaves or extensions 53a. in some embodiments, the 5-pin leaf spring 53 maintains a reliable electrical and mechanical stability even after extended thermal cycling, preventing failure modes such as contact loss, signal drift, or crystal detachment. This structural enhancement distributes mechanical stress more evenly across five contact points 53, improving long-term stability and thermal tolerance of the QCM sensor assembly 50. As a result, the QCM sensor assembly 50 achieves a significantly longer operational lifetime under high-temperature conditions, increasing uptime and reducing replacement costs.

[0045] Referring to FIGS. 3 A and 3B, an embodiment of a prior art QCM sensor system 100 is shown. In some embodiments, the sensor system 100 includes the QCM sensor assembly 50 mounted on a wall of the process chamber 60 (FIG. 3A). In some embodiments, the sensor system 100 includes the QCM sensor assembly 50 mounted on the foreline 70 in semiconductor equipment (FIG. 3B). In some embodiments, the QCM sensor 10 usually operates in a thermally static environment. In FIGS. 3A and 3B, the QCM sensor is integrated into the process system and connected to or otherwise in communication with external electronics, which are used to track the sensor’s output in real time. In some embodiments, the external electronics are configured to receive and analyze signals generated by the QCM sensor assembly 50. In some1232850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 embodiments, the signals pertain to the oscillation frequence of the quartz crystal 12. Tn some embodiments, the external electronics of the QCM sensor assembly 50 may be in communication or otherwise electrically coupled to one or more components external to the process chamber 60 or foreline 70. In some embodiments, the one or more components include a frequency analyzer or frequency monitor 80 and a controller 82. The systems shown in FIGS. 3A and 3B represent the industry-standard deployment of QCM technology for in situ process monitoring.

[0046] However, once the QCM sensor assembly 50 is installed in the positions shown in FIGS. 3 A and 3B, the operating temperature of the QCM sensor 10 becomes inherently fixed by the surrounding environment. Both the wall of the chamber 60 and the foreline 70 are typically maintained at relatively stable temperatures during processing. This thermal stability, while beneficial for minimizing signal noise, imposes a major limitation — there is no mechanism in place to dynamically adjust the temperature of the QCM sensor environment. As a result, the QCM sensor assembly 50 cannot be tuned to operate at application-specific optimal temperatures that may be necessary for detecting temperature-sensitive material behavior.

[0047] This limitation significantly hinders the performance of QCM sensor assemblies 50 in detecting phenomena such as material adsorption, desorption, decomposition, and reaction kinetics, especially when those behaviors only manifest at elevated or tightly controlled temperatures. Without a flexible thermal control system, the QCM sensor assembly’s diagnostic accuracy and application scope are restricted, reducing its utility in advanced or thermally sensitive semiconductor processes.

[0048] Turning to FIGS 4A-D, an embodiment of an enhanced QCM sensor system 200 is shown that is specifically configured to detect ampoule depletion of volatile precursors that readily decompose at elevated temperatures. In the embodiment shown, the QCM1332850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 sensor assembly 50 is installed on the foreline 70 where the ambient temperature remains relatively low and constant. This thermally stable environment makes it difficult to detect volatile precursor materials that do not easily condense at low temperatures because of their much lower melting or boiling points. To overcome this limitation, the system 200 integrates a heating block or a temperature-controlled oven block 210 in which the QCM sensor assembly 50 is housed. In some embodiments, the oven block 210 is configured to operate at temperatures at or above 200°C. In some embodiments, the oven block 210 is comprised of a highly thermally conductive metal. In some embodiments, the highly thermally conductive metal includes silver, copper, gold, aluminum, or combinations thereof.

[0049] In some embodiments, such as shown in FIGS. 5A-D, the oven block 210 further includes an insulated jacket or covering 212 configured to inhibit operator injury or unintended thermal conduction to surrounding tool hardware. Referring to FIG. 5A, in some embodiments, the system 200’ is built as a modular and thermally tunable QCM sensing platform. The addition of a custom insulated covering 212 dramatically improves heat retention and ensures safe handling by keeping surface temperatures below 70 °C, even when the oven block 210 is operating at high temperatures (e.g., 200 °C). In some embodiments, the system 200’ or module 250’ includes a resettable thermal fuse 96 for over-temperature protection, enhancing operational safety and system longevity. In some embodiments, the system 200’ includes dedicated signal output pathways for both temperature and frequency data, enabling real-time feedback loops with process control software.

[0050] In some embodiments, the insulated covering 212 is configured to surround the oven block 210. In some embodiments, the insulated covering 212 forms a thermal barrier to inhibit heat loss, to protect users from accidental bums, and to shield adjacent equipment from1432850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 unnecessary heat exposure. Referring to FIGS. 5A-D, in some embodiments, the insulated covering 212 may be structured to be removably secured about at least part of the oven block 210. Referring to FIG. 5B, in some embodiments, an interior side 212A of the insulated covering 212, when installed, is configured to face the oven block 210. In some embodiments, the interior side 212A is comprised of at least one layer of a high-temperature-resistant, reflective material that insulates the oven block 210 and minimizes radiant heat transfer. Referring to FIG. 5C, the exterior surface or exterior side 212B of the insulated covering 212 is comprised of a stitched material. In some embodiments the insulated covering 212 is comprised of a pliable material. In some embodiments, one or more straps 212C are coupled to, or formed as part of the insulated covering 212. In some embodiments, the one or more straps 212C may be structured to couple to each other and / or a portion of the interior surface or interior side 212A and / or exterior side 212B to facilitate installation of the insulated covering 212 on the oven block 210. In some embodiments, the one or more straps 212C include a hook-and-loop fastener. Still referring to FIGS. 5B-D, strategically placed openings A, B, C accommodate the heater rod 220, RTD sensor 222, and other connection points when the insulated covering 212 is installed on the oven block 210. Turning to FIG. 5D, an embodiment of the insulated covering 212 is shown installed on the oven block 210 with a connection to the heating rod 220 and to the RTD sensor 222 protruding from corresponding openings A, B, C. Once the insulated covering 212 is installed on the oven block 210, the insulated covering 212 maintains a tight seal around the oven block 210 supporting efficient heat retention and safe handling while ensuring continuous access to all electrical and mechanical interfaces.

[0051] Referring back to FIGS. 4A-C, in some embodiments, the oven block 210 includes one or more heater rods 220 and one or more resistance temperature detectors (RTD) 222. The RTD 222 continuously measures the temperature inside the oven block and sends feedback to1532850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 a temperature controller 230. Tn some embodiments, the one or more heater rods 220 and RTDs 222 may be coupled to or bonded to the oven block 210. In some embodiments, the one or more heater rods 220 and RTDs 222 may be bonded to the oven block 210 using a bonding agent that facilitates a homogenous thermal transfer to inhibit hotspots and / or temperature gradients. In some embodiments, the bonding agent may include a thermal epoxy. The uniform heat distribution ensures that the QCM sensor assembly 50 is consistently exposed to the intended thermal setpoint, preserving data integrity and system repeatability even in harsh processing cycles. In some embodiments, the temperature controller 230 facilitates the maintaining of a stable and adjustable thermal environment for systems such as QCM sensor assemblies 50. The setup enables both realtime temperature regulation and external data communication.

[0052] In some embodiments, such as shown in FIGS. 4B and 4C, the temperature- controlled QCM sensor housing 52 includes safety features configured to facilitate a stable and adjustable thermal environment for in-situ sensing in semiconductor processes. In some embodiments, the oven block 210 comprises a thermally conductive metallic structure that at least partially surrounds the QCM sensor assembly 50. In some embodiments, one or more heater rods 220 are inserted into designated slots to provide heat input to the oven block 210. In some embodiments, one or more RTDs 222 are embedded in the oven block 210 to monitor the internal temperature of the oven block 210 in real time. In some embodiments, the one or more heater rods 220 and the one or more RTDs 222 may be thermally bonded to the oven block 210 to ensure uniform temperature distribution. In some embodiments the thermal bonding is accomplished using a thermal epoxy. In some embodiments, the QCM sensor assembly 50 is positioned towards the bottom 211 of the oven block 210 and is in communication with the frequency monitor 80 via a BNC connector 90. In some embodiments the QCM sensor assembly 50 is mechanically fixed1632850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 to the oven block 210 using a clamp member 92. In some embodiments, the clamp member 92 comprises a KF25 clamp and O-ring configured for vacuum compatibility and secure positioning. In some embodiments, the module 250 connects to the process chamber 60 or foreline 70 via a coupler 94. In some embodiments, the coupler 94 comprises a KF25 full nipple extension tube, which provides for easy integration with existing equipment. In some embodiments, a thermal fuse 96 is inserted into the oven block 210 and positioned near the one or more heater rods 210. In some embodiments, the thermal fuse 96 is configured to interrupt power to the heating element if the temperature inside the oven block 210 exceeds a predefined threshold temperature. Accordingly, the thermal fuse 96 inhibits thermal runaway and ensures safe operation of the module 250 in automated environments. Together with the one or more RTDs 222 and closed-loop controller 230, redundant thermal protection is provided. In some embodiments, the controller 82 includes a user interface. In some embodiments, the user interface comprises a software interface. In some embodiments, such as shown in FIG. 4D, the controller 82 is configured to monitor and / or analyze data signals received from the QCM sensor assembly 50. In some embodiments, the controller 82 includes one or more processors 83, memory units, 84, input interfaces 85 and output interfaces86. In some embodiments, the components of the controller are positioned in a common housing87. In some embodiments, the controller 82 is coupled to a network 88.

[0053] Referring to FIGS. 6A-8B, various embodiments of the oven block 210 are shown. These embodiments are not meant to be limiting but are meant to show the versatility of oven block design that may be achieved. Accordingly, reference 210 will be used for general reference to the oven block, while references 210A, 210B, and 210C will be used when referring to specific configurations of the oven block 210. Referring to FIGS. 6A and 6B, in an embodiment, the oven block 210A is machined with threaded holes 216A on two sides that are flush with the1732850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 sealing surfaces to ensure a secure and precise fit. In some embodiments, on both sides of the oven block 210A, two (2) KF claw clamps may be used to secure each KF flange in respective openings 213A, 214A. In some embodiments, each face of the oven block 210A having sealing surfaces will have six (6) helicoils 216A inserted after being drilled and tapped to the specified dimensions in order to provide consistent clamping pressure around the Kalrez O-ring. This may greatly increase the contact surface area due to six fasteners per side. In some embodiments, additional holes or bores 217 may be provided to accommodate other clamping or fastening configurations. In some embodiments, the number and position of the holes or bores 217A are as shown, however in other embodiments, the number and position of the holes 217 may be customized to particular specifications. In some embodiments, additional holes or bores 218 are machines on another face of the oven block 210A to accommodate temperature control components and secure them with screws. In some embodiments, the additional bores 218 comprise a bore 218A to accept the RTD sensor 222, a bore 218B to accept the thermal fuse 96, and a bore 218C configured to accept the heater rod 220. Such modifications ensure the oven block 210A is tailored to meet the specific needs of the application while maintaining high precision and reliability.

[0054] The embodiment of the oven block 21 OB in FIGS. 7A and 7B is structured to ensure the oven block 21 OB maintains an acceptable leak rate (<10-9(torr / L) / min) after the baking process. In some embodiments, the oven block 21 OB enables machining only on the bottom side 21 IB or the QCM sensor side to accommodate a KF half nipple or flange 215B. In some embodiments, the combination of the standard KF clamp and the half shell clamp provides a more leak-tight seal when paired with the oven block and Kalrez O-ring. In some embodiments, the oven block 21 OB configured to accept a standard KF clamp on one end 214B and half shell clamps on1832850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 the other end 213B enables easy assembly and disassembly.

[0055] Referring to FIGS. 8A and 8B, in some embodiments, the oven block 210C includes two (2) KF half nipples or flanges 215C1, 215C2. In some embodiments, each of the half nipples 215C1, 215 C2 of the oven block 210C are structured to accept a KF clamp. In some embodiments, using KF clamps achieves a leak rate below 10’9(torr / L) / min. Moreover, the use of standard KF clamps ensures quick and straightforward assembly, disassembly, and installation, making the oven block 210C both user-friendly and highly effective for maintaining operational reliability.

[0056] In some embodiments, the dimensions of the oven blocks 210A, 210B, 210C may be fixed thereby ensuring compatibility and consistency. This uniformity is crucial for maintaining the performance and reliability of the sensor in various configurations, while also simplifying the assembly process and reducing potential errors.

[0057] Referring to FIGS. 9A and 9B, a wiring diagram of an embodiment of the temperature controller 230 indicates how various components are interconnected inside the temperature controller 230. At the center is the temperature controller module 232, which receives input from an RTD sensor 222 (FIGS. 4A-D). The RTD sensor 222 (FIGS. 4A-D) monitors the real-time temperature of the target environment (e.g., an oven block 210), and its signal is used by the temperature controller 230 to determine whether heating is needed. The temperature controller 230 then uses a solid-state relay to regulate power flow to the heater rod 220, which adjusts the temperature accordingly. Additionally, a temperature real-time output connection 89 (FIG. 5A) is included to export real-time temperature data to external systems for monitoring or logging purposes, enhancing process transparency and traceability. Turning to FIG. 9B, an embodiment of the temperature controller 230 is shown including a housing 234 configured to surround the1932850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 components of FIG. 9A. Each labeled port corresponds to a connection described in the wiring diagram. The Heater Rod Connection Point 235, RTD Connection Point 236, and Power Connection Point 237 ensure seamless integration with external hardware components, while the Temperature Output Connection Point (a DB9 port) 238 facilitates data transmission to a host computer or monitoring unit (such as the controller 82).

[0058] Turning back to FIGS. 4A-D, in some embodiments, the temperature controller 230 is connected to an energy source 226. In some embodiments, the energy source 226 comprises an electrical energy source. In some embodiments, the temperature controller 230 is configured to adjust the power delivered to the heater rod 220 accordingly, ensuring that the oven block 210 — and therefore the QCM sensor assembly 50 — remains at the desired setpoint. In some embodiments, the system 200 enables the QCM sensor assembly 50 to operate in a customized thermal environment, which enables the detection of volatile precursors that may not otherwise react or condense at lower, uncontrolled temperatures. In some embodiments, the oven block 210 includes the thermal fuse 96. In some embodiments, the thermostat comprises a robust and resettable switch that disconnects the power supply to the heater rod 220 if the temperature of the oven block 210 exceeds a defined safety threshold. Once the temperature drops back below that threshold, the circuit is automatically re-engaged. This safety redundancy eliminates the risk of overheating damage to both the sensor assembly 50 and nearby tool components. Moreover, when paired with the digital temperature feedback system, this feature allows for intelligent fault detection, safe system recovery, and reliable long-term use in automated fab environments

[0059] In some embodiments, the system 200 creates a fully isolated and precisely adjustable thermal environment for the QCM sensor assembly 50 using a combination of the heater rods 220, RTDs 222, and a closed-loop temperature controller 230. In some embodiments, the2032850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 system 200 decouples the performance of the QCM sensor assembly 50 from the fixed thermal conditions of its installation site by enclosing it within a temperature-controlled module 250. In some embodiments, the temperature controlled-module 250 includes an integrated heating rod 220, an RTD 222, and a temperature control feedback system that allows the QCM sensor assembly 50 to operate in a customized thermal environment, tailored to match the specific precursor or process conditions. In some embodiments, the module 250 includes the heating block 210. The modular, KF-compatible form factor ensures seamless integration into existing fab infrastructure without the need for system redesign, which reduces adoption costs and deployment friction. Importantly, the durability of the system 200 and the thermal tunability make the system 200 suitable for nextgeneration material development, as it can be quickly adapted to new precursors and novel chemistries. Additionally, by enabling synchronized, multidimensional data collection, such as temperatures and frequency shifts, it lays a strong foundation for smart manufacturing. The system 200 empowers advanced analytics, such as machine learning-based process modeling, predictive maintenance, and reaction mechanism studies. This capability significantly enhances the QCM’s accuracy, sensitivity, and diagnostic range across a wider spectrum of semiconductor applications

[0060] Accordingly, the system 200 allows the sensor assembly 50 to operate under optimal thermal conditions, decoupled from the chamber wall 60 or foreline 70 temperature, enabling high-fidelity detection of temperature-sensitive material behavior. In some embodiments, the system 200 is configured to continuously output real-time thermal data, which allows for precise monitoring of temperature stability and fluctuation around the QCM sensor assembly 50. In some embodiments, the real-time thermal data acquisition is synchronized with frequency signals from the QCM sensor assembly 50. In some embodiments, by monitoring thermal drift with sensor assembly 50 response behavior, users can diagnose deviations, adjust process2132850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 conditions proactively, and ensure optimal thermal stability for the QCM sensor assembly 50 measurements.

[0061] By tightly regulating the sensor assembly’s thermal surroundings, embodiments of the disclosed system 200 ensure that even highly volatile precursors can undergo decomposition or surface reactions on the QCM crystal 12, resulting in measurable frequency shifts. In some embodiments, these frequency changes, monitored in real-time via a frequency monitor and software interface 82, provide critical information about the presence or absence of precursor material, thus allowing accurate detection of ampoule depletion.

[0062] In some embodiments, the system 200 incorporates a comprehensive solution that enable precise adjustment of the QCM sensor assembly’s local operating temperature, independent of the chamber 60 or foreline 70 conditions. This holistic approach ensures that the QCM sensor assembly 50 can operate under its optimal thermal conditions, regardless of where the QCM sensor assembly 50 is installed. Moreover, the system 200 exhibits an improved ability to detect and respond to volatile precursor dynamics and enhances the accuracy, consistency, and applicability of QCM-based monitoring over a broad range of deposition chemistries and materials.

[0063] Existing systems lack a practical mechanism to mitigate contaminants and reaction byproducts accumulating on the crystal surface, impeding its oscillation and leading to signal degradation or complete sensor failure. This often requires replacement of the sensor assembly 50, replacement of the crystal 12, chemical cleaning, or manual cleaning of the sensor assembly 50. By enabling controlled heating of the sensor assembly 50 to elevated temperatures, the system 200, 200’ including the temperature-controlled oven block 210 facilitates on-demand thermal decomposition or evaporation of surface buildup, thereby restoring the sensor assembly’s2232850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 active surface without interrupting the process or requiring disassembly. Accordingly, the system 200 extends the usable lifetime of the quartz crystal 12 as well as improves measurement reliability, reduces downtime, and lowers operational costs. Periodic heating of the QCM sensor assembly 50 environment allows the controlled decomposition or evaporation of surface buildup (crystal contamination), preventing oscillator failure and significantly prolonging the functional lifetime of the sensor assembly 50. Accordingly, embodiments of the system 200, 200’ represent a significant departure from existing QCM sensor assemblies by transforming a static, passively mounted sensor into a dynamic, thermally optimized, and self-maintaining analytical tool suitable for the most demanding semiconductor manufacturing environments.

[0064] Depending on the properties of the materials involved, in some embodiments, elevating the QCM sensor assembly’s 50 operating temperature may facilitate the thermal decomposition or evaporation of accumulated residues on the surface of the quartz crystal 12. This active removal of buildup prevents excessive mass loading that could otherwise dampen or halt the oscillation of the quartz crystal 12. By periodically or continuously maintaining a temperature that discourages residue accumulation, the surface of the quartz crystal 12 of the sensor assembly 50 remains cleaner and more responsive. Therefore, the crystal 12 — and thus the entire QCM sensor assembly 50 — can operate reliably for extended periods, even in harsh or contamination-heavy semiconductor processing environments. This approach significantly enhances sensor longevity and minimizes the need for frequent maintenance or replacement.

[0065] As a result, embodiments of the disclosed system 200, 200’ not only solves the limitations posed by fixed-temperature environments but also expands the scope and value of QCM technology across a wide range of advanced semiconductor applications. Embodiments of the disclosed system 200 decouples the performance of the sensor assembly 50 from the fixed2332850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 thermal conditions of its installation site by enclosing it within the temperature-controlled module 230. This capability significantly enhances the accuracy, sensitivity, and diagnostic range of the QCM sensor assembly 50 across a wider spectrum of semiconductor applications.

[0066] Referring to FIG. 10, in some embodiments, shows a real-time monitoring of the temperature control 270 (left Y-axis) and QCM sensor fundamental frequency response 280 (right Y-axis). During the monitoring, the setpoint of the temperature controller 230 was set to 200°C and the local temperature surrounding the QCM sensor assembly 50 was precisely regulated by a combination of the heater rod 220, the RTD sensor 222, the thermal fuse 96, and the closed- loop temperature controller 230. As shown in the graph of FIG. 10, when the system 200 has completed the heating ramp, the RTD sensor temperature data is fed to the controller 82. FIG. 10 shows the results of this data which demonstrate the ability of the temperature controller 230 to reach and maintain the desired setpoint with minimal fluctuation, approximately ±1 °C. Such tight thermal regulation is critical for ensuring the repeatability and accuracy of QCM sensor assembly 50 measurements in temperature-sensitive thin-film deposition processes with volatile precursors like CCTBA and Cp(Co)CC>2. This shows that the system 200 is capable of regulating the thermal environment of the QCM sensor assembly 50 with high precision and extracting meaningful, high- resolution diagnostic data from the frequency behavior under elevated temperatures.

[0067] The fundamental oscillation frequency of the QCM (Quartz Crystal Microbalance) sensor assembly 280 is highly sensitive to both surface mass loading and thermal effects. It is important to note that each type of QCM crystal 12 possesses a specific temperature- to-frequency calibration curve, meaning that even small temperature changes can induce measurable frequency shifts. However, in FIG. 6, the local temperature remains tightly controlled within a narrow range of approximately 199 °C to 201 °C, yet the frequency still shows notable2432850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 changes, suggesting that the observed frequency behavior is not solely due to the intrinsic thermal response of the quartz crystal 12. During the initial ramp-up phase, the frequency rises gradually, which is most likely caused by the thermal desorption of loosely bound volatile species or surface contaminants from the surface of the quartz crystal 12. As the temperature stabilizes, the frequency trend begins to plateau, indicating that the surface of the quartz crystal 12 has likely reached a cleaner, more stable state. Interestingly, at around the 400-second mark, there is a pronounced frequency spike, which may be attributed to the decomposition or evaporation of more strongly adsorbed residues, signaling a more intensive in-situ thermal cleaning process. This behavior underscores the system’s ability to apply controlled heating not only for thermal regulation but also for active maintenance of sensor performance. By enabling the decomposition or removal of surface buildup directly within the operational environment, the system 200 effectively restores the baseline condition of the sensor assembly 50, thereby extending the functional lifetime of the sensor assembly 50 and ensuring its continued measurement reliability in demanding semiconductor process conditions.

[0068] In some embodiments, the QCM sensor assembly 50 is configured to measure frequency changes caused by the deposition of solid films. These frequency changes are continuously tracked by the frequency monitor 80, which processes the data to provide precise evaluations of precursor consumption and the depletion status of the ampoule. In some embodiments, data from the frequency monitor 80 and temperature controller 230 are integrated into the controller 82, which includes a software interface, allowing operators to monitor system performance in real time and make quick adjustments to maintain system stability, ensuring optimal performance during semiconductor manufacturing processes. Accordingly, even though the oven block 210 is producing conditions sufficient to cause film deposition onto the quartz2532850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 crystal 12, an empty ampoule results in no (or very little) pre-cursor entering the oven block 210. As a result, no (or very few) decomposition / reactions occur and no (or very little) film will be deposited on the QCM sensor crystal 12. With no (or very little) film deposition on the QCM sensor crystal 12, the QCM frequency over time will be flat (i.e., the frequency will not change or change very little over time). Alternatively, if the ampoule is not empty or otherwise contains precursor, then this pre-cursor will flow into the oven block 210 leading to decomposition / reactions. The decomposition / reactions lead to film deposition onto the QCM sensor crystal 12, which causes a frequency change (decrease).

[0069] Current QCM systems rely on the natural condensation of precursors onto the sensor surface under specific foreline conditions. While effective for detecting low-volatility precursors, this approach fails to capture sufficient condensation from highly volatile precursors with high vapor pressure like CCTBA and Cp(Co)C02, often resulting in minimal or unreliable frequency changes. The disclosed systems and methods overcome these limitations by using the oven block 210 equipped with integrated heating 220 functionality. By creating a precisely controlled temperature differential between the QCM sensor 50 and the foreline 70, the oven block 210 facilitates conditions that enable highly volatile precursors to undergo thermal decomposition or chemical reactions. These processes generate solid deposits that form directly on the QCM sensor’s crystal 12 surface. Unlike conventional methods, this approach ensures significant mass changes, producing distinct and measurable frequency shifts caused by film deposition on the QCM sensor, even for precursors that would otherwise remain in a gaseous state under standard conditions. The frequency shifts caused by film deposition on the QCM crystal 12 directly correlate to precursor consumption.

[0070] By extending the range of detectable precursor materials and enhancing2632850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 sensitivity, the invention provides a more versatile and reliable solution. The disclosed systems and methods not only improve the accuracy of ampoule depletion monitoring but also expand the capabilities of QCM systems to meet the demands of advanced semiconductor fabrication processes. The disclosed systems and methods overcome the inherent limitations of conventional systems and enables a broader range of applications, particularly in advanced semiconductor processes where precision and reliability are critical. The disclosed systems and methods have clear industrial applicability and are specifically configured for use in semiconductor fabrication, where monitoring precursor depletion is vital for process optimization and material efficiency.

[0071] Use of the oven block 210 in the disclosed systems and methods creates a controlled temperature differential between the foreline 70 and the QCM sensor assembly 50. This enables highly volatile precursors, like CCTBA and Cp(Co)CO2, to undergo thermal decomposition or chemical reactions, forming solid films on the QCM sensor’s surface. Unlike traditional systems that rely on condensation alone, this approach ensures accurate mass detection even for precursors with high vapor pressures that are typically challenging to monitor. The oven block 210 serves as a connection between the foreline 70 and the QCM sensor assembly 50 as well as a reaction chamber 60 for volatile precursors. This multifunctionality reduces system complexity while ex-tending the range of detectable precursors, making the disclosed systems and methods highly versatile for diverse semiconductor applications. By facilitating reliable tracking of precursor depletion, it supports precise process control and material efficiency, which are critical for modern semiconductor manufacturing.

[0072] While the present invention has been particularly shown and described with reference to certain exemplary embodiments, it will be understood by one skilled in the art that various changes in detail may be affected therein without departing from the spirit and scope of2732850556.1PATENTATTORNEY DOCKET NO. 3221419WO01 the invention that can be supported by the written description and drawings. Further, where exemplary embodiments are described with reference to a certain number of elements, it will be understood that the exemplary embodiments can be practiced utilizing either less than or more than the certain number of elements.2832850556.1

Claims

PATENTATTORNEY DOCKET NO. 3221419WO01CLAIMS1. A monitoring system for semiconductor processes, comprising an oven block configured to couple to one of: (i) a foreline; or (ii) a process chamber, and defining an interior space; a QCM sensor assembly including a QCM sensor configured to be positioned within the interior space of the oven block, wherein the QCM sensor comprises a quartz crystal; one or more heating rods configured to heat the interior space of the oven block to create a thermal environment for the QCM sensor assembly; one or more temperature detectors positioned in the oven block and configured to measure a temperature of the thermal environment; a temperature controller in communication with the one or more heating rods and the one or more temperature detectors and configured to control the thermal environment; a frequency analyzer configured to monitor a frequency of the quartz crystal; and a controller configured to receive and analyze signals from the frequency analyzer, wherein the thermal environment is adjusted based on the received and analyzed signals from the frequency analyzer.

2. The monitoring system of claim 1, wherein the controller is configured to receive signals from the temperature controller, wherein the thermal environment is adjusted based on the received and analyzed signals from the frequency analyzer and the temperature controller.

3. The monitoring system of claim 1 , further comprising an insulated covering configured to at least partially surround the oven block.

4. The monitoring system of claim 3, wherein the insulated covering is comprised of a reflective material that is configured to be formed at least partially around the oven block.

5. The monitoring system of claim 1, further comprising a thermal fuse configured to be positioned in the thermal environment and to interrupt power to the one or more heating rods when the thermal environment exceeds a predefined threshold temperature.2932850556.1PATENTATTORNEY DOCKET NO. 3221419WO016. The monitoring system of claim 1 , wherein the oven block defines a first opening dimensioned to accept the QCM sensor assembly and a second opening configured to be coupled to one of: (i) the foreline; or (ii) the process chamber.

7. The monitoring system of claim 6, wherein at least one of the first opening and the second opening includes a flange.

8. The monitoring system of claim 1, wherein the QCM sensor assembly comprises a retainer assembly and a holder configured to cooperate with the retainer assembly to retain the quartz crystal.

9. The monitoring system of claim 8, wherein the holder defines an opening dimensioned to expose the QCM sensor to an external environment.

10. A method of monitoring semiconductor processes, comprising: structuring an oven block to couple to one of: (i) a foreline; or (ii) a process chamber, and defining an interior space; structuring a QCM sensor assembly to include a quartz crystal configured to be positioned within the interior space of the oven block; heating the interior space of the oven block to create a thermal environment for the QCM sensor assembly; continuously measuring a temperature of the thermal environment; continuously monitoring and analyzing a frequency of the crystal; and controlling the thermal environment based on the monitored and analyzed frequency.

11. The method of claim 10, further comprising controlling the thermal environment based on the monitored and analyzed frequency and the measured temperature.

12. The method of claim 11, further comprising automatically stopping the heating of the interior space when the temperature of the thermal environment exceeds a predefined threshold temperature.3032850556.1PATENTATTORNEY DOCKET NO. 3221419WO0113. The method of claim 10, further comprising positioning an insulated covering to at least partially surround the oven block.

14. The method of claim 10, further comprising structuring the oven block to define a first opening dimensioned to accept the QCM sensor assembly and a second opening configured to be coupled to one of: (i) the foreline; or (ii) the process chamber.

15. The method of claim 14, further comprising structuring at least one of the first opening and the second opening includes a flange.

16. The method of claim 10, further comprising structuring the QCM sensor assembly to include a retainer assembly and a holder configured to cooperate with the retainer assembly to retain the QCM sensor.

17. The method of claim 16, further comprising structuring the holder to define an opening dimensioned to expose the QCM sensor to an external environment.3132850556.1

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