Microsystem module online airtightness leak detection device and method based on humidity sensor

Abstract

The invention relates to the technical field of microsystem module air tightness detection, in particular to a microsystem module online air tightness leak detection device and method based on a humidity sensor, and the device comprises a microsystem module, the humidity sensor embedded and integrated in the package of the microsystem module, and a detection unit connected with the humidity sensor. The detection unit is connected with the humidity sensor and used for acquiring a humidity signal, monitored by the humidity sensor, inside the microsystem module package, and the controller is connected with the detection unit and used for judging the air tightness state of the microsystem module based on the humidity signal and the quantitative relation between the preset humidity change and the leakage rate; and the output unit is connected with the controller and is used for outputting the air tightness state. According to the invention, in-situ, online and long-term nondestructive monitoring of the airtightness of the microsystem module is realized, and the integrated requirements of different types of microsystem modules can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of air tightness detection of microsystem modules, and in particular to an online air tightness leakage detection device and method for microsystem modules based on a humidity sensor. Background Art

[0002] With the rapid advancement of science and technology, the reliability requirements for electronic devices are becoming increasingly stringent. Hermetic packaging, a key technology for ensuring the long-term stable operation of microsystem modules, effectively isolates the chips within the device from harmful environmental factors such as moisture, contaminants, and corrosive gases, thereby preventing performance degradation and even failure of the chip's internal circuits due to oxidation, electrochemical corrosion, or chemical erosion. In high-end applications such as aerospace and automotive electronics, where reliability is paramount, these microsystem modules often face harsh operating conditions such as extreme temperatures, alternating high and low humidity levels, mechanical vibration, and the continuous corrosion and aging effects of a moisture-heat-chemical complex environment on the packaging materials. These factors can gradually degrade the package's hermeticity, thereby affecting the product's overall performance and service life. Therefore, long-term and effective online monitoring of the hermeticity of the microsystem module's packaging structure is crucial to maintaining its structural stability and functional reliability. Currently, traditional airtightness testing methods have significant limitations when applied to online monitoring of microsystem modules. First, the traditional fluorocarbon crude leak detection method relies primarily on the operator visually observing the surface of the package immersed in fluorocarbon oil for bubbles to qualitatively determine leaks. This method has low detection sensitivity and can only identify large channel-type leaks, but is completely incapable of detecting small permeation-type leaks. Second, after multiple tests, the traditional fluorocarbon crude leak detection method can easily leave fluorocarbon residues on the device surface or at potential leak sites, easily clogging small leaks or contaminating the device, thereby affecting the accuracy of subsequent more precise tests and even leading to misjudgments. Furthermore, the judgment criteria vary depending on the operator's experience, lacking objective and quantitative data output. Summary of the Invention

[0003] The present invention aims to provide an online airtightness leak detection device and method for microsystem modules based on a humidity sensor. By integrating an internal humidity sensor, the device converts the airtightness status into a monitorable humidity signal. By combining the quantitative relationship between humidity changes and leakage rate, the device achieves in-situ, online, and long-term nondestructive monitoring of the airtightness of the microsystem module. Furthermore, the device utilizes a specialized capacitive humidity sensor with high sensitivity, small size, and ease of integration, adapting to the integration requirements of various microsystem modules.

[0004] The present invention is achieved through the following technical solutions: An online airtightness leak detection device for a microsystem module based on a humidity sensor includes: a microsystem module, an embedded humidity sensor integrated inside the package of the microsystem module, a detection unit connected to the humidity sensor, for obtaining a humidity signal inside the package of the microsystem module monitored by the humidity sensor, a controller connected to the detection unit, for judging the airtightness status of the microsystem module based on the humidity signal and a preset quantitative relationship between humidity change and leakage rate; and an output unit, the output unit being connected to the controller and for outputting the airtightness status.

[0005] Optionally, the humidity sensor is a capacitive humidity sensor, and the detection unit is a capacitance detection unit, which is used to detect a change in capacitance of the capacitive humidity sensor to reflect humidity changes.

[0006] Optionally, the capacitive humidity sensor includes: a silicon-based substrate, an interdigitated electrode structure formed on the silicon-based substrate, and a polyimide humidity-sensitive material layer covering the interdigitated electrode structure; wherein, after the polyimide humidity-sensitive material layer absorbs moisture, its dielectric constant changes, causing the capacitance value between the interdigitated electrodes to change.

[0007] Optionally, the capacitive humidity sensor is implemented as a silicon-based discrete bare chip device, and is integrated and interconnected with other electronic components within the microsystem module package via a substrate.

[0008] Optionally, the microsystem module is specifically a silicon-based micromodule, and the capacitive humidity sensor is in-situ prepared on a silicon adapter board of the silicon-based micromodule, and is integrated with a functional chip in the silicon-based micromodule through silicon vias and surface rewiring.

[0009] A method for online air tightness detection of a microsystem module based on a humidity sensor, the method comprising the following steps: Embed an integrated humidity sensor inside the package of the microsystem module to monitor the humidity inside the package in situ; Periodically driving the humidity sensor to work and collecting the signal outputted by the humidity sensor indicating the real-time humidity inside the package; Compare and analyze the collected humidity signal with a preset quantitative model, which is constructed based on the corresponding relationship between the humidity change inside the package and the module leakage rate; Based on the comparison and analysis results, the current airtightness status of the microsystem module is determined, and airtightness status information is output.

[0010] Optionally, the humidity sensor is periodically driven to operate, and a signal outputted by the humidity sensor indicating the real-time humidity inside the package is collected, which is specifically as follows: The controller issues a detection instruction to the detection unit according to a preset detection cycle; The detection unit responds to the detection instruction to obtain and process the real-time output of the humidity sensor.

[0011] Optionally, the specific construction process of the preset quantitative model is as follows: Experiments were conducted on reference microsystem modules with different known leakage rates to calibrate the response curves of the humidity inside their packages over time. Based on the response curve, a mathematical relationship between the rate of change of humidity inside the package and the module leakage rate is established to form the quantitative model.

[0012] Optionally, the determining of the current airtightness status of the microsystem module is specifically: When determining whether the leakage rate calculated based on the quantitative model exceeds a preset alarm threshold; If not, it is determined that the airtightness of the microsystem module has not degraded, and the humidity sensor is continued to be driven periodically to work, and the signal output by the humidity sensor of the real-time humidity inside the package is collected; If so, it is determined that the airtightness of the microsystem module has deteriorated, and an alarm is issued through the output unit.

[0013] Optionally, the humidity sensor is specifically a capacitive humidity sensor comprising a polyimide humidity-sensitive material layer, and the capacitive humidity sensor is integrated with a heating unit. Between humidity signal acquisition cycles, the heating unit is started to heat the polyimide humidity-sensitive material layer to promote dehumidification of the polyimide humidity-sensitive material layer and reduce its hysteresis effect, thereby completing accurate detection of the humidity sensor.

[0014] The technical solution of the present invention has at least the following advantages and beneficial effects: On the one hand, the present invention innovatively embeds an integrated high-sensitivity capacitive humidity sensor inside the microsystem module package, which can cleverly convert the package airtightness state that is difficult to directly observe into an internal humidity signal that can be monitored in real time. By pre-experimentally calibrating and establishing an accurate quantitative relationship model between the package internal humidity change and the module leakage rate, the in-situ, real-time, non-destructive and long-term online monitoring of the module sealing performance is achieved, and the traditional airtightness detection scheme must be shut down to remove the module for welding and disassembly, thereby making it impossible to carry out the technical bottleneck of in-situ online monitoring. On the other hand, the capacitive humidity sensor adopted by the present invention is prepared based on advanced silicon-based semiconductor thin film technology. Its core adopts interdigital electrode configuration design, and polyimide is preferably used as humidity-sensitive material. This sensor utilizes the principle that the dielectric constant of the abundant polar groups in the polyimide material changes significantly after combining with water molecules to accurately reflect the change of relative humidity. Moreover, the sensor itself has outstanding advantages such as high sensitivity, small hysteresis effect, fast response time, and compact physical size. This allows it to be used as a discrete silicon-based bare chip device for flexible micro-assembly integration with traditional SiP or hybrid integrated circuit modules. It can also achieve 2D / 2.5D in-situ integration with functional chips through advanced packaging technologies such as through-silicon vias and surface rewiring, thanks to its high compatibility with silicon-based micromodule manufacturing processes. This provides a new, efficient and cost-effective solution for reliability management and full life cycle health monitoring of various microsystem electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the composition of the humidity sensor-based microsystem module online airtightness leak detection device provided by the present invention; Figure 2 Schematic diagram of the humidity sensor provided by the present invention being used for air tightness detection of a traditional micro-assembly module; Figure 3 Schematic diagram of the humidity sensor provided by the present invention used for air tightness detection of silicon-based micromodules; Figure 4 Typical sensor schematic diagram provided by the present invention, including: a) cross-sectional view, b) schematic diagram of the interdigitated electrode pattern layer, and c) schematic diagram of the spiral coil heating layer; Figure 5 Schematic diagram of the preparation of the spiral coil heating electrode and the medium provided by the present invention; Figure 6 A schematic diagram of the preparation of the interdigitated electrode structure provided by the present invention; Figure 7 This is a schematic diagram of preparing the PI humidity-sensitive material layer provided by the present invention; Legend: 1. Microsystem module; 2. Capacitive humidity sensor; 3. High-precision capacitance detection unit; 4. MCU controller; 5. Host computer software. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0017] like Figure 1 As shown, the present invention provides one of the embodiments: an online airtightness leak detection device for a microsystem module based on a humidity sensor, comprising: a microsystem module, an embedded humidity sensor integrated inside the microsystem module package, a detection unit connected to the humidity sensor, for obtaining a humidity signal inside the microsystem module package monitored by the humidity sensor, a controller connected to the detection unit, for judging the airtightness status of the microsystem module based on the humidity signal and a preset quantitative relationship between humidity change and leakage rate; and an output unit, the output unit being connected to the controller, for outputting the airtightness status.

[0018] In this embodiment, the micro-system module online airtightness leak detection device based on the humidity sensor is composed as follows: Figure 1 As shown, it includes a microsystem module, a capacitive humidity sensor, a high-precision capacitance detection unit, an MCU controller and host computer software.

[0019] In the specific implementation of this embodiment, the capacitive humidity sensor is integrated in situ inside the microsystem module. There are two forms of integrating the humidity sensor into the microsystem module. One is a microsystem module for traditional microassembly integration processes such as SiP or hybrid integrated circuits, such as Figure 2 As shown in the figure, the humidity sensor can be used as a silicon-based discrete bare chip device, integrated and interconnected with other devices through a ceramic substrate, and can monitor the water vapor content inside the package and realize the airtightness detection of the sensor micro-assembly module. The second is for advanced packaging micro-system modules such as silicon-based micro-modules, such as Figure 3 As shown, a humidity sensor can be fabricated in situ on a silicon adapter board. Through vertical TSVs and surface rewiring, it can be integrated with functional devices such as analog and digital chips in 2D / 2.5D, enabling in-situ airtightness monitoring of silicon-based micromodules. The humidity sensor's output port is connected to a high-precision capacitance detection unit. The MCU controller issues a test command to the high-precision capacitance detection unit every preset test cycle. When the detected change in water vapor content within the package exceeds a preset threshold, it indicates that the module under test may have experienced airtightness degradation. The host computer software communicates with the MCU controller, enabling graphical parameter setting and test data collection.

[0020] Specifically, the capacitive humidity sensor in this embodiment primarily utilizes semiconductor silicon-based thin-film technology. Through various techniques such as magnetron sputtering and electroplating, the interdigitated electrode (IDE) capacitor structure and spiral coil electrode heating structure are precisely constructed on a silicon substrate. Polyimide (PI) is the preferred humidity-sensitive material, due to its full compatibility with advanced packaging 3D integrated manufacturing processes. It can serve as both a humidity-sensitive material and a dielectric layer. The humidity detection principle is based on the fact that PI contains abundant polar groups (such as carbonyls and imide rings). These groups are highly polar and can hydrogen-bond with water molecules. In its dry state, PI has a low dielectric constant (approximately 2.9), while water has a dielectric constant of up to 80. Upon absorbing moisture, water molecules enter the material, significantly increasing its overall dielectric constant. Figure 4 This diagram shows a typical interdigital humidity sensor fabricated using this method. It consists of a silicon wafer, a silicon oxide insulating layer, a spiral coil heating electrode pattern layer, sensor interdigital electrode patterns (IDE-1 and IDE-2), and a PI humidity-sensitive material layer. The PI humidity-sensitive material covers the interdigital electrodes. Changes in humidity cause changes in the dielectric constant of the humidity-sensitive material, resulting in changes in the capacitance between the interdigital electrodes, which in turn reflects the humidity level. The spiral coil heating layer promotes dehumidification of the humidity-sensitive material through heating, eliminating the hysteresis effect that makes the humidity-sensitive material susceptible to water vapor adsorption / desorption in low-humidity environments.

[0021] Furthermore, this embodiment also provides a method for preparing a capacitive humidity sensor. The main preparation process is as follows: Using conventional size SOI silicon wafers, such as 4-inch, 6-inch, and 8-inch wafers, a silicon dioxide layer is first grown in an oxidation furnace using a dry-wet-dry method, and then a spiral heating coil layer structure is prepared. Figure 5 As shown, a titanium seed layer is sputtered on the front of the wafer to enhance the adhesion between the metal and the silicon oxide layer. Then, metal material (preferably tungsten, but also gold and copper) is deposited through electroplating. Photoresist is spin-coated onto the wafer surface, and the spiral coil pattern is engraved through photolithography. The interlayer dielectric layer is prepared through vacuum film lamination and patterned by photolithography to create windows. The dielectric layer material is generally organic or inorganic, and mainly provides insulation between different signal interconnect metals. Then the metal structure of the interdigitated electrode pattern layer is prepared, such as Figure 6 As shown, a metal material (preferably gold, but copper can also be used) is deposited by magnetron sputtering / electroplating process, a photoresist is spin-coated onto the wafer surface, an interdigitated electrode structure is prepared by photolithography process, and the silicon wafer after photolithography is placed under a metallographic microscope to check whether the photolithographic pattern is consistent with the mask pattern; Finally, the PI humidity sensitive material layer is prepared, such as Figure 7As shown, first place the dried silicon wafer on a spinning machine, use a dropper to drop 4-5 drops of polyamic acid on the center of the silicon wafer, first use a low speed to evenly coat the polyamic acid on the surface of the silicon wafer, then increase the speed to 6000r / min and keep it for 55 seconds; then carry out imidization, first from 30℃ to 150℃, keep it for 1 hour, then increase to 250℃, keep it for 1h, then channel 50℃, keep it for 2h; spin-coat photoresist onto the wafer surface, perform electrode PI windowing through photolithography process, and immerse gold through chemical plating process for device external lead bonding.

[0022] This embodiment also provides another embodiment: an online airtightness leak detection method for a microsystem module based on a humidity sensor, the method comprising the following steps: Embed an integrated humidity sensor inside the package of the microsystem module to monitor the humidity inside the package in situ; Periodically driving the humidity sensor to work and collecting the signal outputted by the humidity sensor indicating the real-time humidity inside the package; Compare and analyze the collected humidity signal with a preset quantitative model, which is constructed based on the corresponding relationship between the humidity change inside the package and the module leakage rate; Based on the comparison and analysis results, the current airtightness status of the microsystem module is determined, and airtightness status information is output.

[0023] In the specific application of this embodiment, the quantitative model construction process is primarily based on experimental calibration. First, a batch of reference microsystem modules with different known leak rates is prepared, and the same humidity sensors used in actual applications are integrated within the packages of these modules. These reference modules are then placed under specific, controllable environmental conditions (e.g., constant external temperature and humidity). The internal humidity sensors continuously monitor and record the complete response curve of the humidity within each module package over time. Finally, data analysis is performed on the collected humidity response curves of each module with known leak rates, focusing on the relationship between the rate of change of humidity within the package (e.g., the increase in humidity per unit time, or the time required to reach a specific humidity value) and the known leak rate of the module. Through mathematical fitting, statistical analysis, or the creation of a lookup table, a mathematical model or database is accurately established that quantitatively describes the relationship between the humidity change characteristics within the package and the actual leakage rate of the module.

[0024] Furthermore, when implementing detection functions using this quantitative model, the following steps are involved: First, a capacitive humidity sensor integrated in situ within the microsystem module package to be tested is driven by the MCU controller according to a preset detection cycle, and a high-precision capacitive detection unit collects the humidity signal inside the module package in real time. Next, the controller or host computer software inputs the collected humidity change data (particularly the rate of humidity change) over a period of time into a previously constructed quantitative model. Based on the input real-time humidity changes, the model reversely calculates the equivalent leakage rate of the current microsystem module to be tested. Finally, the system compares this calculated leakage rate, or an airtightness parameter directly reflected by the degree of humidity change, with a pre-set threshold representing an acceptable airtightness level. If the calculated value exceeds the preset threshold, the airtightness of the microsystem module is determined to have degraded or failed, and a corresponding alarm or status indication is issued through an output unit such as the host computer software.

[0025] To sum up, this embodiment specifically uses semiconductor thin film technology to prepare a high-sensitivity humidity sensor, monitors the water vapor content in the packaging cavity through the embedded integrated capacitive humidity sensor in the microsystem module, combines the MCU controller, high-precision capacitance detection unit and host computer software, and uses the water vapor permeation rate to reversely infer the leakage rate, thereby avoiding module shutdown, disassembly and unsealing contamination, supporting non-destructive full-cycle monitoring from packaging completion to terminal use, and realizing in-situ, online, non-destructive and long-term monitoring of the airtightness of the microsystem module.

[0026] The above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A microsystem module online airtightness leak detection device based on a humidity sensor, characterized in that: include: a microsystem module, a humidity sensor embedded in an integrated interior of the microsystem module package, a detection unit connected to the humidity sensor, configured to obtain a humidity signal within the microsystem module package monitored by the humidity sensor, and a controller connected to the detection unit, configured to determine an airtightness status of the microsystem module based on the humidity signal and a preset quantitative relationship between humidity change and leakage rate; and an output unit connected to the controller and configured to output the airtightness status.

2. The humidity sensor-based microsystem module online airtightness leak detection device according to claim 1, characterized in that: The humidity sensor is specifically a capacitive humidity sensor, and the detection unit is specifically a capacitance detection unit, which is used to detect a change in the capacitance value of the capacitive humidity sensor to reflect a change in humidity.

3. The humidity sensor-based microsystem module online airtightness leak detection device according to claim 2, characterized in that: The capacitive humidity sensor includes: a silicon-based substrate, an interdigital electrode structure formed on the silicon-based substrate, and a polyimide humidity-sensitive material layer covering the interdigital electrode structure; wherein, after the polyimide humidity-sensitive material layer absorbs moisture, its dielectric constant changes, causing the capacitance value between the interdigital electrodes to change.

4. The humidity sensor-based microsystem module online airtightness leak detection device according to claim 3, characterized in that: The capacitive humidity sensor is a silicon-based discrete bare chip device, which is integrated and interconnected with other electronic components inside the microsystem module package through a substrate.

5. The online airtightness leak detection device for microsystem modules based on humidity sensors according to claim 4 is characterized in that: The microsystem module is specifically a silicon-based micromodule, and the capacitive humidity sensor is in-situ prepared on a silicon adapter board of the silicon-based micromodule and integrated with a functional chip in the silicon-based micromodule through silicon vias and surface rewiring.

6. A method for online air tightness detection of a microsystem module based on a humidity sensor, characterized in that: The steps of the method include: Embed an integrated humidity sensor inside the package of the microsystem module to monitor the humidity inside the package in situ; Periodically driving the humidity sensor to work and collecting the signal outputted by the humidity sensor indicating the real-time humidity inside the package; Compare and analyze the collected humidity signal with a preset quantitative model, which is constructed based on the corresponding relationship between the humidity change inside the package and the module leakage rate; Based on the comparison and analysis results, the current airtightness status of the microsystem module is determined, and airtightness status information is output.

7. The online airtightness leak detection method for a microsystem module based on a humidity sensor according to claim 6, characterized in that: The humidity sensor is periodically driven to work, and the signal outputted by the humidity sensor indicating the real-time humidity inside the package is collected, which is specifically as follows: The controller issues a detection instruction to the detection unit according to a preset detection cycle; The detection unit responds to the detection instruction to obtain and process the real-time output of the humidity sensor.

8. The online airtightness leak detection method for a microsystem module based on a humidity sensor according to claim 7, characterized in that: The specific construction process of the preset quantitative model is as follows: Experiments were conducted on reference microsystem modules with different known leakage rates to calibrate the response curves of the humidity inside their packages over time. Based on the response curve, a mathematical relationship between the rate of change of humidity inside the package and the module leakage rate is established to form the quantitative model.

9. The online airtightness leak detection method for a microsystem module based on a humidity sensor according to claim 8, characterized in that: The determining of the current airtightness status of the microsystem module is specifically as follows: When determining whether the leakage rate calculated based on the quantitative model exceeds a preset alarm threshold; If not, it is determined that the airtightness of the microsystem module has not degraded, and the humidity sensor is continued to be driven periodically to work, and the signal output by the humidity sensor of the real-time humidity inside the package is collected; If so, it is determined that the airtightness of the microsystem module has deteriorated, and an alarm is issued through the output unit.

10. The online airtightness leak detection method for a microsystem module based on a humidity sensor according to claim 9, characterized in that: The humidity sensor is specifically a capacitive humidity sensor including a polyimide humidity-sensitive material layer, and the capacitive humidity sensor is integrated with a heating unit. Between humidity signal acquisition cycles, the heating unit is started to heat the polyimide humidity-sensitive material layer to complete accurate detection of the humidity sensor.

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