A semiconductor device-based detection system and design method

Abstract

The application relates to a semiconductor device-based detection system and design method, which is characterized in that a ceramic baseband is attached to the outer peripheral side of an etching integrated cavity inner cylinder and extends along a spiral line, a whole weak reflection fiber grating array is arranged in a baseband slot; a fiber demodulation module is connected with the array to collect wavelength drift of each grating in real time, a data processing module receives the drift and outputs real-time strain data of the outer peripheral side of the inner cylinder. The detection system realizes 360-degree quasi-distributed temperature / strain monitoring without changing the cavity structure, overcomes the problems of insufficient coverage of thermocouple point measurement and missing of thermal-mechanical coupling information, maintains high precision and stability in a high-temperature and high-frequency environment, and significantly improves the real-time early warning capability of the FDC for transient abnormalities, assembly looseness and local overheating in the etching-coating process.

Description

Technical Field

[0001] This invention relates to workshop inspection systems, and more particularly to an inspection system and design method based on semiconductor equipment. Background Technology

[0002] In modern semiconductor manufacturing, the thermal and mechanical stability of the reaction chamber structure has a critical impact on process yield and equipment reliability. Especially in high-frequency thermal cycling processes such as wafer etching and coating, the temperature gradients and stress fluctuations experienced by components inside the chamber can easily cause microstructure deformation, positioning deviations, or sealing failures. Therefore, the industry widely relies on FDC (Fault Detection and Classification) systems to monitor the operating status of critical components in real time and provide fault warnings, ensuring continuous and stable equipment operation and improving process window control capabilities. Against this backdrop, achieving high-precision sensing of the thermomechanical response of the chamber structure itself has become a key supporting means for realizing closed-loop FDC control.

[0003] Existing integrated wafer deposition and etching equipment (such as the technical solution described in CN118571795A) includes a main reaction chamber for plasma reaction, a stage for supporting the wafer, and a coil structure for exciting the radio frequency magnetic field. Internally, it contains upper and lower inner cylinders, a shield, and other components to form a controllable process cavity field. When the equipment switches between etching and deposition modes, the cavity temperature gradient changes drastically. This not only causes dynamic changes in thermal expansion and contraction on the outer periphery of the inner cylinder but also dynamically disturbs the position of the shield, the stress state of the coil, and the gaps in the auxiliary cavities.

[0004] However, current methods for detecting inner cylinder deformation or temperature non-uniformity typically rely on point-based temperature sensors such as thermocouples, which struggle to reflect continuous spatial changes and fail to provide effective feedback on structural deformation. Therefore, there is an urgent need to develop a semiconductor-based detection system to address these issues. Summary of the Invention

[0005] The purpose of this invention is to provide a detection system based on semiconductor devices that integrates a ceramic substrate and a weakly reflective fiber optic grating array. The system combines slotted wiring design with multi-segment arc-shaped chip packaging to provide strain and temperature sensing capabilities with full coverage of the outer periphery of the inner cylinder and high spatial resolution without damaging the original cavity structure. This significantly improves the real-time detection performance and process control response accuracy of the FDC system.

[0006] The technical solution adopted by the present invention to solve the above problems is: a detection system based on semiconductor equipment, including a monitoring device for detecting the deformation of the outer periphery of the inner cylinder in an etching integrated cavity, the monitoring device comprising:

[0007] A ceramic base strip is disposed on the outer periphery of the inner cylinder. The ceramic base strip extends and is formed along a spiral direction. A groove is formed on the ceramic base strip along its own forming direction.

[0008] A weakly reflective fiber Bragg grating array, wherein the weakly reflective fiber Bragg grating array is disposed within the slot;

[0009] An optical fiber demodulation module is connected to the weakly reflective fiber grating array to obtain wavelength drift information of each grating in the weakly reflective fiber grating array.

[0010] A data processing module, which is connected to the fiber optic demodulation module, is used to determine the real-time strain data of the outer periphery of the inner cylinder based on the wavelength drift information.

[0011] Preferably, the monitoring device further includes a fixing layer, which is disposed between the ceramic substrate and the outer periphery of the inner cylinder. The fixing layer is a high thermal conductivity and high temperature resistant adhesive layer to bond and fix each section of the ceramic substrate to the outer periphery of the inner cylinder.

[0012] Preferably, the monitoring device further includes a retaining layer that fills the space between the slot and the weakly reflective fiber Bragg grating array to encapsulate the weakly reflective fiber Bragg grating array within the ceramic substrate.

[0013] Preferably, the retaining layer is a high thermal conductivity and high temperature resistant curable adhesive layer, and the retaining layer is configured to apply a pre-tension force to the weakly reflective fiber Bragg grating array during curing.

[0014] Preferably, the groove has an arc segment when viewed in cross-section, the arc segment corresponding to the inner wall of the groove near the inner cylinder side, and the diameter of the arc segment is equal to the outer diameter of the weakly reflective fiber grating array.

[0015] Preferably, the ceramic base strip is composed of several ceramic pieces spliced ​​together. The ceramic pieces are shaped to fit the outer surface of the inner cylinder on the side closest to the inner cylinder, and a preset gap is left between two adjacent ceramic pieces.

[0016] Preferably, the groove has an arc segment when viewed in cross-section, the arc segment corresponding to the inner wall of the groove near the inner cylinder side, and the diameter of the arc segment is equal to the outer diameter of the weakly reflective fiber grating array.

[0017] The ceramic base strip is composed of several ceramic pieces spliced ​​together. The shape of the ceramic pieces near the inner cylinder is designed to fit the outer surface of the inner cylinder, and a preset gap is left between two adjacent ceramic pieces.

[0018] The monitoring device also includes:

[0019] A fixing layer is provided between the ceramic substrate and the outer periphery of the inner cylinder. The fixing layer is a high thermal conductivity and high temperature resistant adhesive layer to bond and fix each section of the ceramic substrate to the outer periphery of the inner cylinder.

[0020] A retaining layer is provided, which fills the space between the groove and the weakly reflective fiber Bragg grating array to encapsulate the weakly reflective fiber Bragg grating array within the ceramic substrate. The retaining layer is a high thermal conductivity and high temperature resistant curable adhesive layer, and the retaining layer is configured to apply a pre-tension force to the weakly reflective fiber Bragg grating array during curing.

[0021] Specifically, a design method for the detection system described above includes:

[0022] Obtain the physical parameters of the weakly reflective fiber Bragg grating array to determine the minimum permissible bending radius;

[0023] The physical parameters of the retaining layer, the effective bonding length of the weakly reflective fiber grating array when it is connected to the inner wall of the slot through the retaining layer, the target strain transfer rate, the minimum thickness of the retaining layer, and the processing / assembly tolerance are obtained to determine the slot width.

[0024] Obtain the edge safety distance, and determine the initial width of the ceramic tile based on the groove width and the edge safety distance;

[0025] The thermal cycling strength constraint and strain transfer sensitivity constraint are obtained to correct the initial width of the ceramic slab and determine the thickness range.

[0026] Obtain the outer radius of the inner cylinder, and determine the lower limit of the pitch of the helix based on the minimum allowable bending radius and the outer radius of the inner cylinder;

[0027] Obtain the desired minimum strain / temperature wavelength and the target axial coverage coefficient, and determine the upper limit of the pitch of the helix based on the desired minimum strain / temperature wavelength, the corrected width of the ceramic patch, and the target axial coverage coefficient;

[0028] The lower limit of the pitch of the helix is ​​compared with the upper limit of the pitch of the helix. If the lower limit of the pitch of the helix is ​​less than or equal to the upper limit of the pitch of the helix, the pitch of the helix is ​​limited to be between the lower limit of the pitch of the helix and the upper limit of the pitch of the helix. If the lower limit of the pitch of the helix is ​​greater than or equal to the upper limit of the pitch of the helix, the lower limit of the pitch of the helix and the upper limit of the pitch of the helix are re-determined by adjusting at least one of the following: the desired minimum strain / temperature wavelength, the target axial coverage coefficient, the physical parameters of the weak reflection fiber grating array, the corrected width of the ceramic patch and / or the weak reflection fiber grating array, the holding layer, and the material type of the ceramic patch, until the lower limit of the pitch of the helix is ​​less than or equal to the upper limit of the pitch of the helix.

[0029] Preferably, the step of obtaining thermal cycling strength constraints and strain transfer sensitivity constraints to correct the initial width of the ceramic tessellation and determine the thickness range includes the following steps:

[0030] The physical parameters of the ceramic slabs, the linear expansion coefficient of the inner cylinder material, the maximum temperature cycle amplitude, and the safety factor are obtained to determine the minimum allowable thickness corresponding to the thermal cycle strength constraint.

[0031] The maximum allowable thickness corresponding to the strain transfer sensitivity constraint is determined based on the physical parameters of the weak reflection fiber grating array, the target strain transfer rate, and the physical parameters of the holding layer.

[0032] Obtain the upper limit of thermal inertia, adjust the initial width of the ceramic tile according to the minimum allowable thickness, the maximum allowable thickness and the upper limit of thermal inertia, and select the ceramic tile thickness that satisfies the minimum allowable thickness and the maximum allowable thickness.

[0033] Preferably, the design method further includes, if the minimum allowable thickness is greater than the maximum allowable thickness, gradually increasing the width of the ceramic tile by a predetermined increment, and recalculating the minimum allowable thickness and the maximum allowable thickness with the increased width; cyclically performing the calculation operation of increasing the width of the ceramic tile until the re-obtained minimum allowable thickness is not greater than the maximum allowable thickness and meets the limit of the thermal inertia upper limit, thereby determining the final width of the ceramic tile.

[0034] The beneficial effects of the embodiments of the present invention are as follows:

[0035] 1. Because this technical solution adopts an integrated packaging method that uses a ceramic substrate-grooved structure spirally extending along the outer periphery of the inner cylinder and cooperates with the entire weak reflection fiber grating array (WFBG), and obtains the wavelength drift of each grating point in real time through the fiber demodulation module and converts it into strain information by the data processing module, it can achieve 360° quasi-distributed continuous temperature / deformation monitoring of the outer periphery of the inner cylinder without changing the original mechanical layout of the cavity. This effectively solves the technical problems of insufficient spatial coverage of point sensors such as thermocouples and the inability to synchronously obtain thermal-mechanical coupling deformation data in the prior art. Thus, while ensuring the measurement accuracy and stability in high temperature and high radio frequency electromagnetic environment, it significantly improves the FDC system's real-time capture capability of transient anomalies in etching-coating process and the early warning sensitivity of hidden dangers such as loose cavity assembly and local overheating.

[0036] 2. Because this design method employs a parametric calculation approach that acquires the physical parameters of the optical fiber, retaining layer, ceramic tiles, and inner cylinder materials item by item and iteratively corrects them according to thermal cycling strength constraints, strain transfer sensitivity constraints, and thermal inertia upper limits, it can ensure during the design stage that the slot width, ceramic tile width-thickness combination, and helical pitch simultaneously meet multiple constraints such as no bending of the optical fiber, no strain attenuation, no temperature filtering, and no blind spots in coverage. This effectively solves the technical problems in existing technologies where the helical layout dimensions rely on experience and it is difficult to balance structural safety and measurement continuity. As a result, it achieves comprehensive, high-precision, and quasi-distributed monitoring of thermal expansion and contraction on the outer periphery of the inner cylinder, and provides repeatable and verifiable dimensional basis for subsequent mass manufacturing. Attached Figure Description

[0037] Figure 1 This is a schematic partial cross-sectional view of a monitoring device proposed in one embodiment of the present invention.

[0038] Figure 2 This is a schematic structural view of a ceramic substrate surrounding the outer peripheral sidewall of the inner cylinder, as proposed in one embodiment of the present invention.

[0039] Figure 3 This is a schematic structural view of two adjacent ceramic tiles connected by a filler element in one embodiment of the present invention. Figure 1 .

[0040] Figure 4 This is a schematic structural view of two adjacent ceramic tiles connected by a filler element in one embodiment of the present invention. Figure 2 .

[0041] Figure 5 This is a flowchart of a design method for comprehensive monitoring of the outer periphery of the inner cylinder, proposed in one embodiment of the present invention.

[0042] Figure 6 yes Figure 4The flowchart mentioned in step S400 for determining the final width of the ceramic tile.

[0043] Among them: 10, ceramic baseband; 110, ceramic patch; 120, slot; 20, weak reflection fiber grating array; 30, fixing layer; 40, holding layer; 50, filler; 60, inner cylinder. Detailed Implementation

[0044] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0045] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] Please see Figures 1 to 4In a preferred embodiment of this application, a detection system based on semiconductor equipment is provided. This system is suitable for real-time monitoring of semiconductor equipment with an etched integrated cavity structure, particularly for monitoring thermally induced deformation or assembly displacement on the outer periphery of the inner cylinder 60, thereby serving the online sensing requirements for process stability and structural health status in the FDC system. The detection system mainly includes a monitoring device disposed on the outer periphery of the inner cylinder 60 of the integrated cavity equipment. The monitoring device includes a ceramic substrate 10, a weakly reflective fiber grating array 20, an optical fiber demodulation module, and a data processing module. The ceramic substrate 10 is disposed on the outer periphery of the inner cylinder 60, and the ceramic substrate 10 extends in a spiral direction. A groove 120 is formed on the ceramic substrate 10 along its own forming direction. The weak reflection fiber grating array 20 is disposed in the groove 120. The fiber demodulation module is connected to the weak reflection fiber grating array 20 to obtain the wavelength drift information of each grating in the weak reflection fiber grating array 20. The data processing module is connected to the fiber demodulation module to determine the real-time strain data of the outer periphery of the inner cylinder 60 based on the wavelength drift information.

[0048] Specifically:

[0049] The ceramic substrate 10 has a spiral ribbon structure and is installed and formed tightly against the outer periphery of the inner cylinder 60 along the axial spiral direction. The ceramic substrate 10 body is made of alumina or silicon nitride material with high thermal stability, high insulation and high hardness. Its outer surface has a groove 120 extending along the forming direction. The groove 120 is preferably an arc-shaped groove when viewed in cross-section. Its curvature matches the outer diameter of the optical fiber to be embedded to ensure a stable fit.

[0050] The low-reflection fiber Bragg grating array 20 is embedded in the slot 120 of the ceramic substrate 10 using a continuous deployment method. This array extends along a spiral path along its length, and multiple low-reflection fiber Bragg grating units are distributed on it. It possesses low reflectivity characteristics, enabling quasi-distributed strain monitoring without affecting the system's multiplexing capability for other fiber optic signals. To ensure stable array embedding and good strain response, a retaining adhesive layer is preferably used for fiber encapsulation, allowing the fiber to obtain appropriate pre-tension during adhesive curing, thereby improving strain transfer efficiency.

[0051] The fiber optic demodulation module is connected to the weakly reflective fiber optic grating array 20 via optical fiber and is configured to continuously acquire wavelength drift information of each grating unit in the array. The fiber optic demodulation module can be a spectral scanning demodulator or a demodulation unit employing an tunable narrowband filter, used to resolve the minute wavelength drift signals caused by slight structural variations. Subsequently, the demodulated wavelength drift information is input to the data processing module via a communication interface.

[0052] The data processing module is configured to perform real-time physical quantity calculations based on wavelength drift data and preset wavelength-strain / temperature calibration curves. The module can combine multi-grid data to reconstruct the temperature field changes and minute deformation distribution on the outer periphery of the inner cylinder 60, enabling monitoring and analysis of the thermal stress distribution and dynamic stability behavior of the cavity structure.

[0053] The installation of this detection system does not require modification of the cavity structure. It achieves all-round coverage through spiral structure application, adapts to the continuous stress sensing requirements under cavity thermal deformation conditions, and is suitable for precision detection scenarios under complex conditions such as high temperature and high frequency magnetic field.

[0054] In this embodiment, due to the adoption of an integrated packaging method that uses a ceramic substrate 10-groove 120 structure spirally extending along the outer periphery of the inner cylinder 60 and cooperates with the entire weak reflection fiber grating array 20, combined with the real-time acquisition of wavelength drift and dynamic analysis of strain data by the fiber demodulation module and the data processing module, the problem of insufficient spatial coverage and inability to acquire continuous deformation information of point sensors such as thermocouples in the prior art is effectively solved. Thus, quasi-distributed real-time monitoring of the structural deformation of the inner cylinder 60 is achieved without changing the cavity structure, which significantly improves the response capability and early warning efficiency of the FDC system in semiconductor equipment to thermo-mechanical coupling anomalies.

[0055] Please see Figures 3 to 4 In some embodiments, the ceramic base strip 10 is composed of a plurality of ceramic pieces 110 spliced ​​together. The ceramic pieces 110 are shaped to fit against the outer surface of the inner cylinder 60 on the side closest to the inner cylinder 60, and a preset gap is left between two adjacent ceramic pieces 110.

[0056] Specifically:

[0057] The ceramic tile 110 is an arc-shaped plate structure. Its thickness, curvature, and length are pre-parameterized to match the installation curvature required by the helical path. The ceramic tile 110 is preferably made of ceramic materials with high thermal stability and high mechanical strength, such as alumina or silicon nitride, which have good thermal conductivity and low coefficient of thermal expansion, making them suitable for extreme conditions such as high temperature and high frequency electromagnetic fields.

[0058] The outer contours of each ceramic tile 110 near the inner cylinder 60 are precision machined, with their radius of curvature matching the outer surface of the inner cylinder 60. This ensures a tight fit during installation and prevents localized thermal stress concentration caused by suspension. Simultaneously, to accommodate stress release due to structural thermal expansion and contraction and to allow for installation flexibility, a pre-set gap is provided between two adjacent ceramic tiles 110. The size of this gap is calculated based on the maximum operating temperature range of the cavity and the coefficient of thermal expansion of the ceramic, ensuring structural integrity while preventing mutual compression or warping mismatch between the tiles due to thermal expansion.

[0059] During the structural assembly process, the ceramic pieces 110 are sequentially attached to the outer surface of the inner cylinder 60 along the spiral path and positioned by an external fastening structure (not shown in the figure) or a guide groove (not shown in the figure) to form a ceramic baseband 10 channel that extends continuously along the spiral direction, providing a mechanical support platform for embedding the weak reflection fiber grating array 20.

[0060] The ceramic tile 110 splicing structure not only facilitates modular assembly, maintenance, and replacement in areas with limited space or varying curvature, but also effectively releases local thermal expansion and contraction stress while maintaining a high degree of fit, thereby improving the long-term reliability and encapsulation precision of the structure.

[0061] In this embodiment, the ceramic base strip 10 is formed by splicing multiple ceramic pieces 110, and the splice bonding surface is precisely designed according to the outer surface of the inner cylinder 60 and a reasonable gap is reserved. Therefore, the problem of structural fracture or poor bonding caused by thermal stress concentration in the integral rigid ceramic structure in the prior art is effectively solved. Thus, while achieving high bonding and high stability packaging, the modular adaptability of the structure and the reliable operation capability under thermal cycling environment are enhanced.

[0062] Please see Figures 3 to 4 To improve the continuity of the reflective fiber Bragg grating array layout and the stability of the packaging along the spiral path of the ceramic substrate 10, in some embodiments, a filler 50 is provided at a preset gap between two adjacent ceramic pieces 110. The filler 50 is detachably connected to the ceramic piece 110, and when the ceramic substrate 10 spirally wraps around the outer periphery of the inner cylinder 60 and is fixedly attached thereto, the reflective fiber Bragg grating array and the filler 50 abut against each other away from the inner cylinder 60.

[0063] Specifically:

[0064] The filler 50 is arranged along the spiral path of the ceramic substrate 10, and its cross-sectional shape matches the end contour of the ceramic tile 110. Structurally, it forms an interference fit with the tile or achieves a detachable connection through snap-fit, slot, screw connection, or other means. Preferably, the filler 50 is made of a high-performance insulating material with certain flexibility and thermal stability, such as polyimide-based composite material, ceramic-reinforced composite rubber, or low-expansion engineering plastic, to adapt to expansion compensation under thermal cycling conditions and maintain the uniformity of the overall encapsulation structure.

[0065] The filler 50 serves not only as a flexible unit for thermal stress buffering in the gaps between the panels, but also provides necessary mechanical support during fiber optic deployment. When the weak-reflection fiber Bragg grating array 20 is arranged along the groove 120 and passes through the splicing gap area of ​​the two ceramic panels 110, the filler 50 provides continuous support to its bottom, preventing micro-bending, sagging, or strain distortion of the optical fiber due to "suspended" conditions in this area. After the ceramic substrate 10 is wrapped around the outer periphery of the inner cylinder 60 and fixed in place, the filler 50 abuts against the outer surface of the optical fiber on the side facing away from the inner cylinder 60, thereby forming a complete optical fiber embedding channel, improving the overall packaging consistency and signal demodulation accuracy of the system. Furthermore, the filler 50 can be easily removed during maintenance or replacement of the optical fiber, avoiding the impact of local fixation on the extraction and replacement process of the entire optical fiber, and improving the maintainability and reliability of the detection system.

[0066] In this embodiment, by employing a technique of placing a filler 50 at a preset gap between ceramic tiles 110 and having the filler 50 abut against the side of the reflective fiber grating array away from the inner cylinder 60, the structural discontinuity problem of easy instability, sinking, or strain distortion at the gaps between the tiles in the prior art is effectively solved. This not only achieves complete support for the spirally arranged optical fiber but also improves the mechanical uniformity of the packaging structure and the accuracy of temperature strain sensing, thereby enhancing the long-term operational stability and detection reliability of the system under thermal cycling conditions.

[0067] To further improve the stability and measurement accuracy of the detection system under complex thermal environments, please refer to [link / reference needed]. Figure 4 In some embodiments, the monitoring device further includes a fixing layer 30 and a retaining layer 40. The fixing layer 30 is disposed between the ceramic substrate 10 and the outer periphery of the inner cylinder 60. The fixing layer 30 is a high thermal conductivity and high temperature resistant adhesive layer to adhere and fix each segment of the ceramic substrate 10 to the outer periphery of the inner cylinder 60. The retaining layer 40 fills between the groove 120 and the weak reflection fiber grating array 20 to encapsulate the weak reflection fiber grating array 20 within the ceramic substrate 10. The retaining layer 40 is a high thermal conductivity and high temperature resistant curable adhesive layer. The retaining layer 40 is configured to apply a pre-tension force to the weak reflection fiber grating array 20 during curing.

[0068] Specifically:

[0069] The fixing layer 30 is used to reliably attach the multiple ceramic substrate strips 10 to the outer surface of the inner cylinder 60. It is a high-temperature resistant adhesive layer with high thermal conductivity and adaptability to high-temperature environments. The fixing layer 30 can be made of inorganic adhesives or polymer-modified composite materials with good thermal conductivity and low coefficient of thermal expansion. It is formed into a uniform adhesive film layer by scraping, dispensing, or pressing processes. During assembly, it achieves a firm bond to the ceramic substrate strips 10 through thermosetting or UV curing. The thickness of this adhesive layer is designed in combination with the radius of curvature of the inner cylinder 60 and the surface flatness of the ceramic pieces 110, and is usually controlled in the range of micrometers to several hundred micrometers to ensure heat conduction efficiency and avoid local stress concentration.

[0070] The retaining layer 40 is used to encapsulate the weakly reflective fiber Bragg grating array 20 within the groove 120 of the ceramic substrate 10. Its material is a curable adhesive layer with high thermal conductivity and good temperature stability. During the filling process, by controlling the coating pressure and the interference fit of the groove, the retaining layer 40 allows the optical fiber to obtain axial micro-tension under the encapsulation of the curable adhesive layer, thereby preventing grating relaxation, deformation drift, or signal abnormalities caused by thermal expansion or mechanical disturbance. The retaining layer 40 preferably uses a prepolymer colloid or a low-viscosity thermosetting resin system. Combined with the groove microstructure, it is cured in situ within the groove 120 through heat treatment, providing not only flexible encapsulation and protection but also forming a highly efficient mechanical coupling with the optical fiber, ensuring reliable transmission of strain energy to the sensing area.

[0071] In practical applications, the fixing layer 30 and the retaining layer 40 work together to ensure the reliable bonding between the ceramic baseband 10 and the inner cylinder 60, while also enhancing the packaging consistency between the optical fiber and the baseband. Its overall packaging structure is suitable for extreme conditions such as high temperature, high-frequency electromagnetic fields, and prolonged thermal cycling, helping to maintain the accuracy and stability of long-term system monitoring.

[0072] In this embodiment, by employing a high thermal conductivity and high temperature resistant fixing layer 30 between the ceramic substrate 10 and the inner cylinder 60, and a retaining layer 40 within the groove 120 to apply pre-tension force to the fiber optic grating array, the problem of poor signal stability and decreased accuracy caused by poor bonding, strain distortion, and thermal stress drift of the sensing components in the prior art is effectively solved. Thus, while improving strain transmission efficiency, the monitoring system achieves long-term reliable operation and near real-time fault early warning capability under high temperature and high stress environments.

[0073] To improve the fit and strain transfer efficiency of the weakly reflective fiber Bragg grating array 20 within the slot 120, please refer to [reference needed]. Figure 4In some embodiments, the groove 120 has an arc segment when viewed in cross-section. The arc segment is disposed on the inner wall of the groove 120 near the inner cylinder 60 and corresponds to the arc segment on the inner wall of the groove 120 near the inner cylinder 60, thereby forming a curved substrate for direct contact with the outer surface of the optical fiber. The diameter of the arc segment is equal to the outer diameter of the weakly reflective fiber Bragg grating array 20.

[0074] Specifically:

[0075] The curvature parameters of the arc segment are precisely designed, and its diameter is equal to the outer diameter of the selected weak reflection fiber grating array 20, so that after the fiber is embedded, a quasi-full contact fit is formed along the entire bottom surface, which significantly reduces signal loss and strain distortion caused by cavities, gaps or point contacts on the bottom surface of the fiber.

[0076] The 120° arc segment of the groove can be formed within the ceramic tile 110 through processes such as laser etching, micro-milling, or ceramic hot pressing preforming. Combined with the viscoelastic properties of the fiber holding adhesive layer, it provides stable initial positioning constraints and long-term holding force during encapsulation. The arc-shaped groove bottom forms an arc-shaped nested mating structure with the optical fiber, which not only effectively limits the axial displacement or lateral sliding of the optical fiber during thermal expansion or mechanical vibration, but also improves the integrity of the adhesive layer covering the sidewall of the optical fiber, thereby ensuring the continuous consistency of signal transmission.

[0077] The slot 120 structure is particularly suitable for applications involving full-length encapsulation of weakly reflective fiber Bragg grating arrays 20. It is compatible with small tolerances in fiber diameter and provides a reference positioning for subsequent encapsulation and pre-stress loading, significantly improving the consistency of module assembly and the stability of sensing performance.

[0078] In this embodiment, by employing the technique of setting an arc segment structure with the same outer diameter as the optical fiber as the optical fiber bonding base surface on the inner wall of the slot 120 near the inner cylinder 60, the problems of poor bonding of optical fibers in the slot 120, unstable strain transmission, and poor signal output consistency in the prior art are effectively solved. This achieves the technical effect of improving packaging consistency and long-term sensing reliability, providing key support for high-precision, quasi-distributed cavity thermal response monitoring.

[0079] To achieve comprehensive and high-precision axial deformation monitoring of the outer periphery of the inner cylinder 60 in an integrated etching device, while avoiding monitoring dead zones and ensuring the sensitivity of defect detection, a design method for an integrated structure of a ceramic substrate 10-fiber grating array based on physical constraints is proposed. (Please refer to...) Figure 5 The design method includes the following steps:

[0080] Step S100: Obtain the physical parameters of the weakly reflective fiber Bragg grating array 20 to determine the minimum allowable bending radius;

[0081] Step S200: Obtain the physical parameters of the retaining layer 40, the effective bonding length of the weak reflection fiber grating array 20 when it is connected to the inner wall of the slot 120 through the retaining layer 40, the target strain transfer rate, the minimum thickness of the retaining layer 40, and the processing / assembly tolerance, so as to determine the width of the slot 120.

[0082] Step S300: Obtain the edge safety distance, and determine the initial width of the ceramic tile 110 based on the width of the groove 120 and the edge safety distance;

[0083] Step S400: Obtain thermal cycling strength constraints and strain transfer sensitivity constraints to correct the initial width of the ceramic patch 110 and determine the thickness range;

[0084] Step S500: Obtain the outer radius of the inner cylinder 60, and determine the lower limit of the pitch of the helix based on the minimum allowable bending radius and the outer radius of the inner cylinder 60;

[0085] Step S600: Obtain the desired minimum strain / temperature wavelength and the target axial coverage coefficient, and determine the upper limit of the pitch of the helix based on the desired minimum strain / temperature wavelength, the corrected width of the ceramic patch 110 and the target axial coverage coefficient;

[0086] Step S700: Compare the lower limit of the pitch of the helix with the upper limit of the pitch of the helix. If the lower limit of the pitch of the helix is ​​less than or equal to the upper limit of the pitch of the helix, limit the pitch of the helix to be between the lower limit of the pitch of the helix and the upper limit of the pitch of the helix. If the lower limit of the pitch of the helix is ​​greater than or equal to the upper limit of the pitch of the helix, redetermine the lower limit of the pitch of the helix and the upper limit of the pitch of the helix by adjusting at least one of the following: the desired minimum strain / temperature wavelength, the target axial coverage coefficient, the physical parameters of the weak reflection fiber grating array 20, the corrected width of the ceramic patch 110, and / or the material type of the weak reflection fiber grating array 20, the holding layer 40, and the ceramic patch 110, until the lower limit of the pitch of the helix is ​​less than or equal to the upper limit of the pitch of the helix.

[0087] Among them, the minimum allowable bending radius determined in step S100 This radius serves as the first safety constraint for designing the lower limit of the helical pitch. It needs to be determined based on the mechanical-optical reliability indicators of the selected weakly reflective fiber grating array 20 (WFBG) under high-temperature vacuum, radio frequency electromagnetic, and long-term stress cyclic conditions. The physical parameters used to determine the minimum permissible bending radius of the weakly reflective fiber grating array 20 include:

[0088] Fiber outer diameter Contains polyimide or other high-temperature resistant coatings;

[0089] Define the minimum static bending radius for a given distortion threshold. Or the corresponding maximum allowable bending strain ;

[0090] glass fiber core elastic modulus And the long-term operating temperature range.

[0091] The above parameters can be obtained by consulting the technical manual or supplier specifications of the selected WFBG product during the component selection phase. If the manual does not provide complete data, it can also be measured using a high-precision digital micrometer. And obtain it from the supplier or through a four-point bending-spectral joint test. Among them, the elastic modulus of the glass fiber core The approximation of 70 gigapascals can be obtained using general-purpose quartz optical fiber or by actual measurement using Raman scattering sound speed.

[0092] Furthermore, considering coating softening and RF-thermal cycling conditions, to avoid insufficient short-term reliability derating, it is necessary to... Environmental calibration is performed. When the operating temperature approaches the upper limit of the fiber's maximum rated temperature, a temperature derating factor is introduced. (Empirical value 0.8 to 0.9). When alternating mechanical vibration or high-frequency magnetic field coupling is present, a fatigue derating factor is introduced. (Experience value 0.9 to 0.95).

[0093] The formula for calculating the minimum permissible radius after correction is:

[0094]

[0095] or only obtained Under these circumstances, according to the expression for the macroscopic bending strain of optical fiber:

[0096]

[0097] The inverse solution yields:

[0098]

[0099] When the actual operating temperature exceeds the nominal temperature rating in the datasheet, the manufacturer's high-temperature bending test curve or IEC thermal aging test data should be consulted to obtain the remaining strength ratio corresponding to the probability of bending failure, which is recorded as the temperature derating factor. When alternating vibration or radio frequency coupling is present, the fatigue life target is converted into the remaining bending strength ratio by referring to the fiber dynamic fatigue n-value (which can be provided by the ASTM F3005 four-point bend-fracture test or the manufacturer's SN curve), and recorded as the fatigue derating factor.

[0100] Alternatively, designers can obtain more accurate temperature derating factors and fatigue derating factors through the following methods.

[0101] Temperature derating factor The method for determining it is as follows:

[0102] First, obtain a reference curve. Request or measure the "critical bending strain-temperature" curve from the fiber optic supplier. If only the critical bending radius-temperature curve is provided, proceed as follows: Converted to strain.

[0103] Secondly, determine the reference point. Select the critical bending strain corresponding to room temperature (or the supplier's nominal reference temperature). As a 100% strength benchmark.

[0104] Then, determine the operating point. Take the highest operating temperature set on the equipment. Read the corresponding critical bending strain on the same curve. .

[0105] Finally, the temperature derating factor is calculated.

[0106]

[0107] If the supplier only provides failure rate curves, the critical strain ratio at a given failure rate level (e.g., one part per million) can be used instead. During verification, at least ten fiber optic samples can be tested in a constant temperature chamber. If there is no fiber breakage or wavelength drift exceeding the limit after bending for twelve hours, then It can be effective; if it fails, it needs to be reduced. The test was repeated until the reliability target was met.

[0108] Fatigue devaluation factor The method for determining it is as follows:

[0109] First, obtain dynamic fatigue parameters. Check the supplier's dynamic fatigue n-value, or conduct a four-point bending "strain rate-breakage strain" test in a constant temperature water bath according to ASTM F3005. n is obtained by regression.

[0110] Secondly, set lifespan targets. Based on the equipment design lifespan or FDC sampling cycle, determine the total number of cycles the fiber must withstand. .

[0111] Then, the durability strain is determined. The lifetime formula of the n-model is used.

[0112]

[0113] Replacing σ with the bending strain form, the calculation is performed in... Corresponding time Internal stress tolerance .

[0114] Next, the fatigue derating factor is calculated. This is based on the static allowable strain. (The result obtained in step one) is the denominator:

[0115]

[0116] Finally, verification was achieved through cyclic testing. A constant amplitude bending cyclic test was performed on the clad optical fiber in room temperature air, and the number of cycles reached [number missing]. If there is no failure afterwards Effective; if invalid, the adjustment needs to be lowered again. .

[0117] It should be noted that all the formulas used above are derived from the publicly available theory of optical fiber mechanical reliability: the Arrhenius-type thermal aging curve is used for temperature reduction, and the n-value fatigue model is used for cycle life estimation. Through three steps—curve reading, ratio calculation, and bench verification—those skilled in the art can quantitatively obtain the results without dispute. This provides a reproducible basis for the subsequent design of the bending safety radius.

[0118] Furthermore, for long-life equipment, to ensure that wear drift remains below a specified threshold during a service life of more than ten years, an overall safety factor can be introduced. (Choose between one and two). Final selection:

[0119]

[0120] This serves as the input for subsequent calculations of the lower pitch limit.

[0121] The overall safety factor is a design margin concept commonly used in reliability engineering specifications. Its specific value can be obtained by consulting tables in the life-strength statistical model, combining the target service life and failure rate indicators, or by using a fiber optic mechanical design margin that further amplifies the static strength by one to two times. Engineers can also select a value between one and two based on the company's internal reliability database, fault tree analysis, or accelerated aging test results.

[0122] Designers will , , , and obtained Enter the design calculation table and simultaneously write the sensor installation specifications of the FDC monitoring system to ensure that the same bending safety constraint is used as the benchmark when iterating the splicing and spiral parameters in subsequent stages.

[0123] In summary, by following the above process, designers can quickly obtain the minimum permissible bending radius that meets the requirements of high-temperature RF operating conditions simply by referring to publicly available data sheets and simple dimensional measurements. This lays a reliable parameter foundation for the safe design of subsequent helical pitch and patch width-thickness combinations.

[0124] In step S200, the width of the slot 120 is determined using parameters such as the physical parameters of the retaining layer 40 and the coupling parameters between the optical fiber and the slot 120. The physical parameters of the retaining layer 40 include its shear modulus and the minimum feasible thickness for manufacturing. The coupling parameters between the optical fiber and the slot 120 include the effective bonding length and the target strain transfer efficiency. Furthermore, step S200 also requires obtaining the processing / assembly tolerances.

[0125] Specifically, the shear modulus of the retaining layer 40 The shear modulus can be recorded by consulting the material data sheet of the selected high-temperature curing adhesive or by conducting dynamic shear rheological tests at room temperature and operating temperature.

[0126] The minimum feasible thickness for the retaining layer 40 is as follows. It is necessary to comprehensively consider the rheological properties of the colloid, the degassing ability, and the processing limit of the tank depth. Furthermore, the minimum film thickness to ensure no air gaps and no shrinkage cracks can be determined through sample curing experiments.

[0127] Effective bonding length The length of the bonded segment at which the stress at both ends of a single grating unit can be sufficiently attenuated can be determined using a shear-hysteresis model. In engineering, this can be taken as the actual grating length of a weakly reflective grating plus the transition sections before and after, or directly as the grating center spacing. This length can be verified through micro-tensile spectroscopy tests.

[0128] Target strain transfer efficiency This refers to the ratio of the measured strain amplitude of the optical fiber to the true strain amplitude of the ceramic surface. It is used to set the upper limit of the 40mm thickness of the retaining layer and can be selected between 0.95 and 0.985 depending on the required measurement sensitivity. For more precise values, the following method can be used:

[0129] First, define the inspection requirements. List the minimum strain characteristic values ​​that must be captured on the FDC side. Based on previous defect reviews or finite element simulations, determine the minimum suspected strain amplitude that a hot spot or assembly loosening will cause. (e.g., 200 microstrain). Determine the allowable error for strain measurement. Based on the process window or yield analysis, a relative error tolerance is given (usually 5% to 10%); the smaller the error, the higher the required transfer efficiency.

[0130] Secondly, quantize the optical demodulation resolution. Obtain the minimum resolvable wavelength drift of the demodulator. (As determined by supplier specifications or experimental calibration) and the wavelength-strain sensitivity of fiber Bragg gratings. (Approximately 1.22 picometers per thousand microstrain). Then, the strain resolution of the system itself is calculated using the following formula:

[0131]

[0132] Next, the target transfer efficiency is derived. To ensure the measured strain amplitude is greater than the instrument noise and falls within the error tolerance, the following can be written:

[0133] for Take the stricter constraint from this formula: If the value on the right falls between 0.95 and 0.98, it can be used directly; if it exceeds 0.98, the demodulation resolution needs to be increased or the tolerance relaxed. .

[0134] Then, considering temperature cross-sensitivity and assembly errors, a margin of 1% to 2% can be added to the calculated value; finally, round to two decimal places as the design value. (e.g., 0.97).

[0135] Finally, sample verification is performed. A standard aluminum or stainless steel tensile sheet is fabricated, and the 40-fiber-ceramic retaining layer to be used is encapsulated to the designed thickness. A stepped strain is applied on a universal strain gauge, and the ratio of the fiber output to the strain gauge data is recorded. If the measured average ratio is... If the value is higher than the design margin and the fluctuation is less than the design margin, then Valid; if lower than It needs to be recalculated and increased. Alternatively, adjust the parameters of the retaining layer 40.

[0136] The above error inequality and ratio formula are both derived from This is derived from conventional error propagation and is a well-known relationship.

[0137] and All can be directly measured experimentally; and The method is derived from process or reliability requirements; therefore, it is fully quantifiable and reproducible.

[0138] By adopting the above process, a clear target strain transfer efficiency can be determined in the design input stage, and the thickness of the retaining layer 40 can be calculated in reverse using the shear-hysteresis model without relying on empirical ranges.

[0139] Machining / Assembly Tolerances It is necessary to combine the repeatability of the tool size of the precision engraving machine tool, the shrinkage error of ceramic sintering and the tolerance of the outer diameter of the optical fiber, and obtain the positive and negative limit values ​​through statistics and take their absolute values.

[0140] After obtaining the above five parameters, substitute them into the shear-hysteresis model to calculate the thickness of the 40mm retaining layer, as shown in the following formula:

[0141]

[0142] Based on the calculated thickness of the retaining layer 40, the width of the groove 120 can be determined using the following formula. .

[0143]

[0144] Get a groove width of 120 Finally, to ensure that the processing is feasible, an additional 5% safety margin can be added before outputting to CAD drawings for the 110 precision grinding or laser-modulated grooving process of ceramic tessellation.

[0145] Furthermore, it should be noted that after the calculation is completed, the strain transfer efficiency should be verified by finite element thermo-mechanical coupling simulation or double cantilever spectral tensile test to see if the target is met. If the efficiency is insufficient, the material of the retaining layer 40 can be adjusted cyclically in this step or the target efficiency can be reset and the calculation repeated until the design specifications are met.

[0146] With the aforementioned clearly defined parameter acquisition process, readily available shear-hysteresis theory formulas, and processing tolerance conversion, those skilled in the art can directly complete the design and process finalization of the 120mm wide slot, achieving efficient strain coupling between the three layers of fiber-ceramic-colloid.

[0147] In step S300, the minimum width of the ceramic tile 110 can be determined by determining the edge safety distance and the width of the groove 120.

[0148] Edge safety distance This refers to the minimum margin from the outer side of the groove wall 120 to the free edge of the ceramic piece 110 (the edge approximately perpendicular to the extension direction of the ceramic piece 110). It is used to prevent edge chipping during processing and edge cracks caused by thermal cycling. Its value should be determined by considering the flexural strength and toughness of the ceramic material, the minimum tool diameter and tool vibration error of the piece processing method (grinding, laser grooving, or micro-milling), the edge stress caused by the maximum temperature cycle amplitude of the inner cylinder 60 due to ceramic thermal expansion and contraction, and the mechanical impact that may occur during assembly and transportation. In practical design, the edge safety distance can be determined based on industry experience and sample test curves: for alumina ceramics, it is recommended to be no less than two millimeters; for aluminum nitride ceramics, this can be relaxed to one and a half millimeters. If laser microgrooving is used and the tool diameter is less than 0.15 millimeters, 0.2 millimeters can be subtracted. Designers should conduct edge static pressure and thermal shock tests on the sample to verify that the selected edge safety distance can ensure that the piece does not chip or crack under full temperature cycle conditions.

[0149] Those skilled in the art can further determine the edge safety distance more precisely in the following ways. ,

[0150] Edge safety distance The equivalent maximum principal tensile stress at the root of the groove must be ensured. Not exceeding the design allowable stress of the ceramic .

[0151]

[0152] in:

[0153] The room temperature flexural strength is measured for standard specimens with four-point bend or three-point bend.

[0154] For reliability and safety factors, a value between one and two is generally chosen.

[0155]

[0156] The bending / impact stress during the assembly or transportation stage can be obtained using a simply supported beam or drop impact model.

[0157] The edge bending stress is caused by the expansion difference between the metal cylinder and the ceramic piece 110.

[0158] This is the stress concentration factor at the root of the trench.

[0159] For the geometry of the slot 120 and the free edge of the plate, Peterson's closed-form solution from "Stress Concentration Factors" is given:

[0160]

[0161] Applicable conditions: Furthermore, ceramics are brittle materials. If If the value is close to or greater than one, a semi-symmetric two-dimensional model can be used with FEA to calculate the maximum principal stress, and the result can still be used with equivalent methods. express.

[0162] Will Substituting the criterion, we derive the explicit formula:

[0163]

[0164] From the following formula:

[0165]

[0166] All of the above parameters can be measured, checked, or calculated directly from assembly load and thermal cycle specifications.

[0167] In practical implementation, information can be obtained through experiments or by consulting manuals. , , , Metal cylinder material Maximum temperature difference Piece thickness ,width Next, test the assembly for drop or clamping loads and calculate... Then, select the safety factor. If zero failure over ten years is required, a value of 1 to 1.5 can be used; if an impact margin is also included, a value of 2 can be used. Then, substitute these values ​​into the above formula to calculate... , then ask If calculated If the processing limits are exceeded or space is limited, iterative optimization can be achieved by reducing the thickness of the splices, widening the splices, or using higher-strength ceramics. Verification can be performed using finite element simulation or crack propagation experiments. Sufficient margin is allowed, and this is recorded in the design documents. The above formula is directly based on the Peterson standard stress concentration factor and GB / T5593 (flexural strength of alumina ceramics) data; the safety factor value can be looked up in the table according to the failure rate target of IEC60300.

[0168] Initial width of ceramic tile 110 It can be obtained through the following formula:

[0169]

[0170] This formula originates from the common practice of leaving a safety margin after the groove in mechanical design, which is to reserve a safety zone of equal width on both sides of the groove width to offset machining errors and thermal stress.

[0171] It is important to note that the calculated initial width should be entered into the CAD model and checked against the tooling fixtures. If the panel width exceeds the 60mm inner cylinder space or the upper limit of the panel's thermal inertia, it should be corrected in conjunction with the thickness in subsequent step S400. Record the final selected edge safety distance. With initial width The parameters, along with the toolpath file, are sent to the ceramic machining section. The formulas and margin principles used in this process are all publicly available conventions in machining and brittle material structure design, which can be directly implemented by those skilled in the art.

[0172] In step S400, obtaining thermal cycling strength constraints and strain transfer sensitivity constraints is used to correct the initial width of the ceramic patch 110 and determine its thickness range. (See also...) Figure 6 Step S400 specifically includes the following steps:

[0173] Step S410: Obtain the physical parameters of the ceramic patch 110, the linear expansion coefficient of the inner cylinder 60 material, the maximum temperature cycle amplitude, and the safety factor to determine the minimum allowable thickness corresponding to the thermal cycle strength constraint;

[0174] Step S420: Determine the maximum allowable thickness corresponding to the strain transfer sensitivity constraint based on the physical parameters of the weak reflection fiber grating array 20, the target strain transfer rate, and the physical parameters of the holding layer 40.

[0175] Step S430: Obtain the upper limit of thermal inertia, correct the initial width of the ceramic tile 110 according to the minimum allowable thickness, the maximum allowable thickness and the upper limit of thermal inertia, and select the thickness of the ceramic tile 110 that satisfies the minimum allowable thickness and the maximum allowable thickness.

[0176] Step S440: If the minimum allowable thickness is greater than the maximum allowable thickness, the width of the ceramic tile 110 is gradually increased by a predetermined increment, and the minimum allowable thickness and the maximum allowable thickness are recalculated with the increased width; the calculation operation of increasing the width of the ceramic tile 110 is performed cyclically until the minimum allowable thickness is no greater than the maximum allowable thickness and the limit of the thermal inertia limit is met, thereby determining the final width of the ceramic tile 110.

[0177] Step S410 determines the minimum allowable thickness under the thermal cycling strength constraint. The calculation process for the minimum allowable thickness is as follows:

[0178] Consult the technical manual of the selected ceramic material or the test report of the four-point bend standard specimen to obtain the elastic modulus. Flexural strength at room temperature (four-point bend value) And its coefficient of linear expansion was measured. ;

[0179] Consult the material handbook for inner cylinder 60 metal (e.g., stainless steel or nickel-based alloy) to obtain its coefficient of linear expansion. ;

[0180] Extract the highest and lowest temperature difference of a complete etching-coating cycle from the process specifications or historical temperature control profiles, and record it as the maximum temperature cycle amplitude. ;

[0181] Based on the target life and failure rate requirements, a safety factor is selected from reliability standards (IEC 60300, etc.). Generally, one to two is chosen;

[0182] Use the initial tile width obtained in the previous step .

[0183] After querying the above parameters, the thermal cycling bending stress model can be calculated.

[0184] When the ceramic patch 110 and the outer wall of the inner cylinder 60 are heated or cooled as a whole, the difference in thermal expansion between the two materials generates outward bending stress, the classical closed solution of which is:

[0185] Require It must not exceed the allowable value In the formula, the allowable stress

[0186] Then, solve for the minimum allowable thickness, and let , combined = It can be obtained explicitly:

[0187] like steady state range This allows for the replacement of more refined piecewise integral forms; such as... If the thermal expansion stress is in the opposite direction, the absolute value can be taken and the calculation can still be performed as described above.

[0188] It should be noted that if the calculation results If the ceramic thickness exceeds the maximum feasible thickness for manufacturing, it is necessary to iterate in subsequent steps by increasing the tile width or switching to low-expansion ceramics. , , , , , , and the result Registered in the design data sheet and in the CAD model as A parametric constraint is established for the lower limit of thickness. Furthermore, it can be quickly verified using a simple two-dimensional thermo-mechanical finite element model. To verify the validity of the design, the sample was subjected to two full-temperature cycles, and the presence of cracks was checked. Furthermore, by calculating using the aforementioned publicly available mechanical formulas and reliability coefficients, designers can quantitatively obtain the minimum thickness of the ceramic patch 110 that meets the thermal cycling strength constraints.

[0189] In step S420, the maximum allowable thickness of the ceramic patch 110 is determined based on the strain transfer sensitivity constraint. This step utilizes the publicly available shear-hysteresis strain transfer theory to quantitatively verify the three-layer structure of "optical fiber-adhesive layer-ceramic". The specific steps are as follows:

[0190] First, obtain the input parameters, including:

[0191] Fiber outer diameter (Including coating), read with a digital micrometer or obtain from the manufacturer's manual;

[0192] Elastic modulus of optical fiber glass core (Obtained through the aforementioned steps);

[0193] Shear modulus of retaining layer 40 (Obtained through the aforementioned steps);

[0194] Target strain transfer efficiency (Obtained through the aforementioned steps);

[0195] 20 effective bonding lengths per grating in a weakly reflective fiber Bragg grating array (Obtained through the aforementioned steps).

[0196] Then, the shear-hysteresis parameter is calculated. Let the fiber radius be... The classical shear-hysteresis model is given under the thin adhesive layer approximation:

[0197]

[0198] in:

[0199] The reciprocal of the value reflects the characteristic attenuation length of strain transmitted from the optical fiber to the ceramic.

[0200] Finally, the maximum thickness is derived. For uniform plate-shaped ceramics, the transfer efficiency of the above model is approximately:

[0201]

[0202] make By numerical inverse kinematics, we can obtain:

[0203]

[0204] in:

[0205] The coefficient 0.9 is the highly simplified coefficient given in the literature. The time error is less than 3%.

[0206] The coefficient 0.9 can be obtained by numerically inversely solving the exact equation of the shear-hysteresis model and then fitting it using least squares. The steps are as follows:

[0207] First, establish a dimensionless variable. Let... Shear-hysteresis precise transfer efficiency formula

[0208]

[0209] Only with related.

[0210] Secondly, define the design range. Engineering design often focuses on target efficiency. Define the interval as ,correspond (Solving numerically) =Constant obtained).

[0211] Next, numerical inverse kinematics is used. Each... Correspondence Construct data pairs .

[0212] Finally, a linear least squares fit was performed on the model:

[0213]

[0214] Perform a linear fit within the selected data interval to minimize the residuals. The fitting results are generally obtained To make rounding easier to remember and to slightly enlarge the value on the safety side, we take... Within the aforementioned efficiency range, the relative error does not exceed approximately 3%.

[0215] During the review, By substituting the approximate and precise formulas and comparing them, an error curve can be plotted, confirming the location of the maximum error approximately at [location missing]. The endpoints are still below the design margin.

[0216] Therefore, the coefficient 0.9 comes from the least squares approximation after numerical inversion of the accurate formula and is rounded safely. If the designer wants to obtain more rigorous coefficients or coefficients for other efficiency ranges, they only need to refit according to the above four steps.

[0217] In practice, first calculate according to the above formula. Then substitute the target Seek ,Will Record this in the design sheet and use it as the subsequent thickness upper limit and the result of step S410. Together, they form a "feasible thickness range" constraint. If In step S440, the width of the patch is increased iteratively or a higher shear modulus adhesive layer is replaced until the constraint is met.

[0218] Understandably, designers can set up a three-layer structure of fiber-adhesive-ceramic in the finite element model, apply axial micro-stretching, and compare the wavelength drift of the fiber grating point with the strain of the ceramic surface to confirm that the actual transmission efficiency is not lower than [previous level]. .

[0219] Step S430 involves correcting the width of the ceramic tile 110 under thermal inertia constraints and selecting a feasible thickness. The specific steps are as follows:

[0220] First, calculate the upper limit of thermal inertia. Measure or read the outer radius of the inner cylinder at 60° from the 3D model. Based on the empirical rule that "thermal inertia should not significantly hysteresis the temperature-strain response," the panel width is limited to:

[0221]

[0222] This coefficient is derived from an empirical critical value that compares the first-order thermal conduction time constant of a thin sheet of the same material with the temperature step response of a cylindrical wall. It can be verified using transient infrared imaging in this field. If there are more stringent time constant indicators, the coefficient can be reduced and the following steps can be repeated.

[0223] Secondly, the feasible thickness range was cross-checked. Starting from the smaller value between the panel width and 0.2 times the inner cylinder radius of 60mm in the calculation table, each item was checked according to the workable thickness step. If there is no solution, then widen the width each time. And recalculate This continues until the first thickness that satisfies both constraints is found, thus locking in the final width-thickness combination.

[0224] Next, take the minimum allowable thickness obtained in the first two steps. With maximum allowable thickness .

[0225] Then, set the initial width value in the CAD or Excel design table. This value comes from step S300.

[0226] After that, check Does it meet the upper limit of thermal inertia? If not, directly take... .

[0227] Finally, the thickness discrete values ​​achievable by the manufacturing process can be calculated or looked up in a table, within the range of... Select a set of thickness candidates. If at least one of them meets the processing limit, it can be recorded as "feasible".

[0228] Step S440 is the iterative relaxation process when there is no solution for the interval. The specific steps are as follows:

[0229] If step S441 finds that the interval has no feasible thickness after step S430, perform iteration:

[0230] Step S4411: Adjust the width of the tiles according to the set increment. (Usually set to 0.5 to 1 mm for easy adjustment of ceramic grinding tools) Increase by one:

[0231]

[0232] Step S4412: Recalculate :

[0233]

[0234] Step S4413: Hold The thickness remains unchanged (determined by shear-hysteresis, which is only related to the adhesive layer and fiber parameters), and the feasible thickness is re-determined according to step S430.

[0235] Step S4414: If there is still no solution and touch If the upper limit is reached, the process will stop, indicating that a low-expansion ceramic, a higher-strength material, or a lower strain transfer efficiency target should be used.

[0236] Step S4415: If the upper limit is not reached and there is still no solution, return to step S4411 and continue the loop until the first occurrence. .

[0237] Step S442: When a feasible thickness exists, start with the minimum thickness that meets the conditions, and select the final thickness by combining the machining tool specifications and the overall machine weight balance. Synchronously lock the final width. .

[0238] Step S443: [The text appears to be incomplete and contains several grammatical errors. A more accurate translation would require the full context.] and Write the 3D model and process flow sheet, and perform a step thermal cycle experiment on the sample to confirm that the temperature-strain response time constant conforms to the FDC system refresh cycle, thus completing this step.

[0239] It should be noted that the upper limit formula for thermal inertia is derived from the steady-state heat transfer approximation of thin plates; the response delay is minimized when the transverse thermal conduction time constant of the ceramic 110 sheet is comparable to the radial thermal diffusion time constant of the inner cylinder 60, hence the width is taken as approximately one-fifth of the cylinder radius; this ratio has been verified in thermal balance tests of multiple devices. Furthermore, the iterative logic uses only publicly available mechanics and heat transfer formulas, which can be quickly implemented in any spreadsheet software or script, ensuring that designers can repeatedly obtain a unique final width-thickness combination.

[0240] In step S500, the lower limit of the helical pitch can be determined based on the bending safety radius. The specific steps are as follows:

[0241] First, determine the outer radius of the inner cylinder (60mm). This can be done directly from the CAD 3D drawing or by measuring the outer diameter of the inner cylinder (60mm) with vernier calipers, then divide by two to obtain the result. The values ​​are then recorded in the design parameter table after being accurate to 0.1 millimeters.

[0242] Next, the calculated minimum allowable bending radius is called.

[0243] The fiber bending safety radius has been obtained in step S100. .confirm If the requirements are not met, a more flexible optical fiber or a more relaxed bending coefficient must be selected; otherwise, spiral installation is not possible.

[0244] Secondly, establish geometric constraint equations.

[0245] The radius of curvature of the helix on the cylindrical surface:

[0246]

[0247] make After simplification, we obtain the lower limit of the helical pitch:

[0248]

[0249] This derivation is derived from the common formula for the curvature of a cylindrical spiral.

[0250] Then, perform numerical calculations and verification. Enter the values ​​in the calculation table. and One-time calculation If a negative value appears within the square root, it indicates that the bending requirement is too strict to allow for spiral wrapping, and the process should return to step S100 to re-evaluate the fiber selection. Round to 0.1 mm and record as "lower limit of pitch".

[0251] Finally, get Write the parameters into the helix parameter table as the lower limit input for comparison in subsequent steps S600 and S700.

[0252] In summary, by using the cylindrical helical curvature formula and the above substitution calculations, those skilled in the art can quickly and unambiguously calculate the lower limit of the helical pitch, thereby ensuring that the optical fiber will not fail prematurely due to excessive bending during installation.

[0253] Step S600 is used to determine the upper limit of the helical pitch. The specific steps are as follows:

[0254] First, obtain the parameters, including:

[0255] Minimum strain / temperature wavelength This refers to the shortest and most detectable spatial characteristic scale of strain or temperature along the 60-degree axial direction of the inner cylinder; that is, when the cavity exhibits a wavelength smaller than... When hot spots, loose assembly, or localized stress concentration occur, their impact on the process or reliability can be considered negligible; however, once a wavelength equal to or greater than [a certain value] appears... For any anomalies, the detection system must be able to accurately identify them. This parameter, provided by the process or FDC engineer, is used to ensure the ability to distinguish defects or hot spots along the shortest axis. This can be confirmed through process simulation. A cavity thermo-mechanical model is established in finite element software, and the heat source distribution, plasma coupling, and assembly tolerances are simulated. The minimum axial feature length L* that produces significant process deviations (e.g., etching rate changes exceeding the upper limit of the process window) is statistically analyzed. ≈L* (or slightly smaller, leaving a monitoring margin); or, retrieve the FDC and yield database to locate typical hot spot / mechanical deformation events that led to scrapping or rework, and use online or offline measurement results to calculate the axial projection length of the corresponding defect on the inner cylinder 60 surface. Take the smallest value in each iteration. Multiply by a safety factor (usually 0.8 to 1) as It can also be measured by the thermal diffusion radius. Based on, among which The thermal diffusivity of the metal, The duration of one process step is... Multiply by two to obtain the complete wavelength of the thermal disturbance, then compare it with the minimum stiffness element of the structure, and take the smaller one. .

[0256] Understandably, designers can cross-check the above three sets of data: if the simulation, defect backtracking, and physical estimation values ​​are close, then the smallest value should be taken; if the differences are significant, the most stringent (smallest) value can be selected. To ensure a safety margin in detection.

[0257] Target axial coverage factor This parameter defines the overlap ratio of adjacent spirals in the axial projection, and is usually taken between 0.8 and 1; the value is determined by the tolerance of the monitoring blind zone.

[0258] The corrected ceramic tile width is 110. This parameter comes from the final tile width that was locked in step S440.

[0259] Secondly, the upper limit of resolution is determined according to the Nyquist criterion to avoid omitting wavelengths. For the strain signal, the helical pitch in the axial direction must satisfy the Nyquist sampling condition:

[0260]

[0261] The original Nyquist sampling theorem states that to fully reconstruct a bandwidth-limited continuous signal, the sampling frequency must be greater than twice the highest frequency of the signal. Mapping this time-domain concept to the spatial domain:

[0262] The signal corresponds to the strain / temperature field distributed on the surface of the inner cylinder 60;

[0263] The sampling corresponds to the sampling interval (i.e., pitch p) of the WFBG helix in the axial direction.

[0264] The highest frequency corresponds to the shortest spatial wavelength .

[0265] Therefore, the sufficient condition for preventing spatial aliasing is:

[0266]

[0267] This is what is introduced in step S600. If the pitch exceeds this value, the wavelength is close to... Anomalies may be misjudged or completely disappear in the demodulation results (spatial aliasing, blind spots); constraining p within the Nyquist limit ensures that the system has the required minimum spatial resolution.

[0268] Next, the geometric upper limit is calculated according to the coverage requirements to ensure that the axial projections of adjacent spiral layers overlap each other. The geometric relationships are given as follows:

[0269]

[0270] Then, determine the upper limit of the pitch, taking the smaller of the two constraints as the upper limit of the pitch:

[0271]

[0272] The specific steps are as follows: Enter the data in the designed table. , , Three values; calculated once using the formula. and Record the smaller value as And retain one decimal place; Write the parameters into the "Helix Parameter Table" for step S700 and the lower limit. Compare.

[0273] Finally, verification and adjustments are still required.

[0274] If subsequent comparisons occur Designers can relax the restrictions appropriately. (If the detection resolution allows) or reduce (Allowing for a small blind spot) or widening again. And iterate according to step S440.

[0275] Step S700 is used to comprehensively verify and determine the feasible range of the helical pitch.

[0276] First, the upper limit and lower limit of the helical pitch are compared. The lower limit of the pitch obtained in step S500 is then used... The upper limit of pitch obtained in step S600 Place them in the same calculation table;

[0277] when Then immediately output the range of values. The process ends when the interval is locked in the design record.

[0278] If it appears If the current parameter set is conflicting, it means that the bending safety requirements and the spatial resolution / coverage requirements cannot be met simultaneously, and backtracking adjustment is required.

[0279] The subsequent item-by-item retrospective adjustment process is as follows:

[0280] (1) Set adjustment priority and increment:

[0281] First, increase the width of the pieces. Increment each time And repeat step S440;

[0282] like If the upper limit of thermal inertia has been reached and there is still no solution, then the coverage factor should be relaxed. Each descent Until it is no lower than 0.7; if there is still no solution, relax the discrimination requirement: Each upward adjustment If the problem persists, a more flexible optical fiber can be used (to reduce the bending coefficient). Alternatively, use a small outer diameter optical fiber or switch to a retaining adhesive with a higher shear modulus; after each replacement, return to step S100 and recalculate. .

[0283] Then, the process is repeated. The logic "while p_min > p_max" is established in the script or table; each time a parameter adjustment is completed, steps S500 to S600 are automatically called to update the new upper and lower limits and the judgment is made again.

[0284] Finally, once it appears The system immediately outputs a new feasible range and records the modified parameters. If all adjustable parameters reach engineering limits and conflicts still occur, an "infeasible" message is automatically generated, requiring engineers to re-evaluate the process window or structural scheme.

[0285] In summary, through the above steps S100 to S700, the width-thickness combination and helical pitch parameters of the ceramic substrate 10 that meet multiple constraints such as bending reliability, efficient strain transmission, thermomechanical safety, and full spatial resolution coverage can be systematically derived. This solves the technical problem that traditional empirical deployment cannot take into account the long-term reliability of optical fibers, measurement accuracy, and monitoring blind spots, and realizes 360-degree quasi-distributed high-precision monitoring of the outer periphery of the etched integrated cavity cylinder 60.

[0286] The above description is merely illustrative of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the content of this specification or exceed the scope defined by the claims, all of which should fall within the protection scope of this invention.

Claims

1. A design method for a detection system based on semiconductor devices, characterized in that, The detection system includes a monitoring device for detecting deformation of the outer periphery of the inner cylinder in the etched integrated cavity, the monitoring device comprising: A ceramic base strip is disposed on the outer periphery of the inner cylinder. The ceramic base strip extends and is formed along a spiral direction. A groove is formed on the ceramic base strip along its own forming direction. A weakly reflective fiber Bragg grating array, wherein the weakly reflective fiber Bragg grating array is disposed within the slot; An optical fiber demodulation module is connected to the weakly reflective fiber grating array to obtain wavelength drift information of each grating in the weakly reflective fiber grating array. A data processing module, which is connected to the fiber optic demodulation module, is used to determine the real-time strain data of the outer periphery of the inner cylinder based on the wavelength drift information. The groove, when viewed in cross-section, has an arc segment, which corresponds to the inner wall of the groove near the inner cylinder. The diameter of the arc segment is equal to the outer diameter of the weakly reflective fiber grating array. The ceramic substrate is composed of several ceramic pieces spliced ​​together. The shape of the ceramic pieces near the inner cylinder is designed to fit the outer surface of the inner cylinder, and a preset gap is left between two adjacent ceramic pieces. The monitoring device also includes: A fixing layer is provided between the ceramic base strip and the outer periphery of the inner cylinder. The fixing layer is a high thermal conductivity and high temperature resistant adhesive layer to bond and fix each section of ceramic pieces to the outer periphery of the inner cylinder. A retaining layer is provided, which fills the space between the groove and the weakly reflective fiber Bragg grating array to encapsulate the weakly reflective fiber Bragg grating array within the ceramic substrate. The retaining layer is a high thermal conductivity and high temperature resistant curable adhesive layer, and the retaining layer is configured to apply a pre-tension force to the weakly reflective fiber Bragg grating array during curing. The design method includes: Obtain the physical parameters of the weakly reflective fiber Bragg grating array to determine the minimum permissible bending radius; The physical parameters of the retaining layer, the effective bonding length of the weakly reflective fiber grating array when it is connected to the inner wall of the slot through the retaining layer, the target strain transfer rate, the minimum thickness of the retaining layer, and the processing / assembly tolerance are obtained to determine the slot width. Obtain the edge safety distance, and determine the initial width of the ceramic tile based on the groove width and the edge safety distance; The thermal cycling strength constraint and strain transfer sensitivity constraint are obtained to correct the initial width of the ceramic slab and determine the thickness range. Obtain the outer radius of the inner cylinder, and determine the lower limit of the pitch of the helix based on the minimum allowable bending radius and the outer radius of the inner cylinder; Obtain the desired minimum strain / temperature wavelength and the target axial coverage coefficient, and determine the upper limit of the pitch of the helix based on the desired minimum strain / temperature wavelength, the corrected width of the ceramic patch, and the target axial coverage coefficient; The lower limit of the pitch of the helix is ​​compared with the upper limit of the pitch of the helix. If the lower limit of the pitch of the helix is ​​less than or equal to the upper limit of the pitch of the helix, the pitch of the helix is ​​limited to be between the lower limit of the pitch of the helix and the upper limit of the pitch of the helix. If the lower limit of the pitch of the helix is ​​greater than or equal to the upper limit of the pitch of the helix, the lower limit of the pitch of the helix and the upper limit of the pitch of the helix are re-determined by adjusting at least one of the following: the desired minimum strain / temperature wavelength, the target axial coverage coefficient, the physical parameters of the weak reflection fiber grating array, the corrected width of the ceramic patch and / or the weak reflection fiber grating array, the holding layer, and the material type of the ceramic patch, until the lower limit of the pitch of the helix is ​​less than or equal to the upper limit of the pitch of the helix.

2. The design method according to claim 1, characterized in that, The process of obtaining thermal cycling strength constraints and strain transfer sensitivity constraints to correct the initial width of the ceramic tessellation and determine its thickness range includes the following steps: The physical parameters of the ceramic slabs, the linear expansion coefficient of the inner cylinder material, the maximum temperature cycle amplitude, and the safety factor are obtained to determine the minimum allowable thickness corresponding to the thermal cycle strength constraint. The maximum allowable thickness corresponding to the strain transfer sensitivity constraint is determined based on the physical parameters of the weak reflection fiber grating array, the target strain transfer rate, and the physical parameters of the holding layer. Obtain the upper limit of thermal inertia, adjust the initial width of the ceramic tile according to the minimum allowable thickness, the maximum allowable thickness and the upper limit of thermal inertia, and select the ceramic tile thickness that satisfies the minimum allowable thickness and the maximum allowable thickness.

3. The design method according to claim 2, characterized in that, include: If the minimum allowable thickness is greater than the maximum allowable thickness, the width of the ceramic tile is gradually increased by a predetermined increment, and the minimum allowable thickness and the maximum allowable thickness are recalculated with the increased width. The calculation operation of increasing the width of the ceramic tile is repeated until the minimum allowable thickness is no greater than the maximum allowable thickness and the limit of thermal inertia is met, thereby determining the final width of the ceramic tile.

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