As precision electronic components, camera modules integrate image sensors, PCBs, connectors, and other components that are mostly packaged in plastic. Such plastic packages are prone to absorbing moisture from the environment; during the high-temperature SMT reflow soldering process, the internal moisture expands when heated, which may cause reliability failures such as package cracking and pin detachment. The Moisture Sensitivity Level (MSL) standard, as the core technical specification defining the moisture-proof capability of camera modules and components, its grading and compliance control directly determine the storage reliability, process compatibility, and long-term operational stability of modules in different humidity environments, thereby affecting the service life and operation and maintenance costs of terminal monitoring systems. For camera module manufacturers and overseas purchasers targeting the global market, accurately grasping the mainstream MSL standards, grade adaptation logic, and control points of camera modules is a key prerequisite for avoiding production and application risks and ensuring product compliance.
The MSL standard for camera modules is not independently formulated but strictly follows the IPC/JEDEC J-STD-020 industry universal mandatory standard. Based on the moisture absorption characteristics of plastic-packaged components, this standard classifies MSL levels into 8 categories (including unlimited level) from low sensitivity to high sensitivity. A smaller level number indicates lower moisture sensitivity of the module and components, with looser storage and production control requirements; a larger level number indicates higher moisture sensitivity and stricter control requirements. It should be clarified that the MSL level of a camera module is not fixed but is jointly determined by the MSL level of its core components, package type, application environment, and process technology. Among them, the MSL levels of image sensors and PCBs are the core factors affecting the overall moisture-proof standard of the module, and the moisture-proof capabilities of the two must be coordinated; otherwise, the overall moisture-proof performance of the module will degrade.
Combined with the global market application scenarios and industry practices of camera modules, the MSL standards for consumer-grade and industrial-grade modules show clear differentiated distribution, among which the mainstream MSL level for consumer-grade camera modules (such as modules supporting mobile phones and tablets) is MSL 3~4. These modules are mostly used in indoor normal temperature and humidity environments, and their core components (such as conventional CMOS sensors and standard plastic-packaged PCBs) mostly adopt medium and low sensitivity packaging. The MSL 3~4 level corresponds to a storage humidity requirement of ≤30%RH; after unpacking, in a conventional workshop environment of 30℃/60%RH, it can be safely placed for 7~168 hours, which can meet the large-scale production control needs of the consumer electronics industry while balancing cost and reliability. It is worth noting that if consumer-grade modules adopt micro ultra-thin plastic-packaged components (such as 0402 chips, thin BGA packaged sensors), their MSL level needs to be upgraded to MSL 5 and above; otherwise, the risk of package cracking during reflow soldering will be significantly increased.
Different from consumer-grade modules, the mainstream MSL level for industrial-grade and outdoor POE camera modules (such as modules supporting smart parks and outdoor monitoring) is MSL 1~2, and some high-end outdoor modules even adopt a combination of components with unlimited MSL level. These modules are long-term exposed to outdoor environments with high humidity and severe temperature fluctuations, and some scenarios need to withstand harsh climate erosion, so higher requirements are put forward for moisture-proof performance. Components corresponding to MSL 1~2 levels mostly adopt ceramic, metal packaging or high-protection plastic packaging technology, which are almost non-hygroscopic or low-sensitive. They do not require special ultra-low humidity storage equipment and can be safely stored in normal temperature and humidity environments. After unpacking, the workshop life is unlimited or up to 1 year, which can effectively avoid module failures caused by moisture intrusion in outdoor environments, while reducing the warehousing and operation and maintenance costs of overseas customers.
The core factors affecting the selection of camera module MSL levels can be summarized into three points, which form a progressive logical relationship: first, package type, the MSL level of plastic-packaged components is generally higher than that of ceramic and metal packaging, and miniaturized, ultra-thin plastic packaging will further improve moisture sensitivity; second, application environment, the higher the environmental humidity and the greater the temperature fluctuation, the lower the required MSL level of the module (stronger moisture-proof capability), which is also the core reason for the difference in MSL levels between outdoor and indoor modules; third, process technology, if the module production adopts a high-temperature reflow soldering process with a peak temperature exceeding 260℃, the MSL level of the same components needs to be upgraded by 1 level to offset the moisture expansion risk aggravated by high temperature. In addition, the overall moisture-proof performance of the module also needs to rely on the optimization of packaging technology, such as the application of potting sealant and waterproof connectors, which can further improve the moisture-proof capability on the basis of the MSL level of components.
It is particularly important to remind overseas purchasers and module manufacturers that the compliance control of MSL levels lies not only in selection but also in the full-life cycle storage and production management. Some manufacturers claim that their modules meet the target MSL level but do not strictly follow the baking requirements of the IPC/JEDEC J-STD-033 supporting standard. For example, if components are not used within the time limit after unpacking but are not baked and dehumidified at 125℃±5℃, the moisture-proof performance of the module will still fail. For overseas customers, during selection, they should require manufacturers to provide MSL level certification reports of the core components of the module, clarify the control requirements after storage and unpacking, and at the same time, combine their own application scenarios to avoid blind pursuit of high-level moisture-proof performance leading to cost waste, or product failures caused by insufficient levels.
In general, the MSL standard for camera modules is based on the IPC/JEDEC J-STD-020, and the mainstream levels show differentiated distribution according to application scenarios. Consumer-grade modules are mainly MSL 3~4, while industrial-grade and outdoor POE modules are mainly MSL 1~2. The selection of MSL level is not the higher the better, but needs to be accurately matched according to package type, application environment and process technology. Its core value is to avoid reliability risks in production and application through scientific moisture-proof control. For overseas customers, mastering this logic can not only accurately select models and control costs but also ensure the long-term stable operation of camera modules through standardized storage and production management, which is also an important technical criterion for the sustainable development of the global precision electronic component industry.
