Description of storage requirements and precautions for electronic components

The life of electronic components with different quality is different, and the life depends on how to use them. If properly applied, the life of electronic components is about 5-10 years. Resistance, inductance, capacitance, semiconductor devices (including diodes, triodes, field transistors, integrated circuits), that is, under the same working conditions, semiconductor devices are most likely to be damaged. According to the statistical reports of device physical failure data from several companies, among the device failure cases induced by various stresses (electrical, mechanical, environmental, moisture sensitive, etc.), the failure of electronic components due to moisture accounts for 15%. With the development of device packaging technology, more and more plastic materials with low water vapor permeability are used in large quantities, and the number of pins is becoming more and more intensive. The control technology of humidity sensitive devices is facing great challenges. Device design requires high integration, and production and processing require higher efficiency, making most of the current devices are surface mount packaging.
Storage requirements of various electronic components warehouse:
1、 Environmental requirements:
Electronic components must be stored in a clean, ventilated, non corrosive gas warehouse indoor environment, and the warehouse should be in a smooth channel state. In addition, the temperature and relative humidity of the warehouse storing electronic components must meet the following requirements: temperature: - 5-30, relative humidity: 20% - 75% RH, and the environmental temperature and humidity value of the warehouse will directly affect the storage life and quality of electronic components.
2、 Special requirements:
1. Static sensitive devices (such as MOS FET, GaAs FET, CMOS circuit, etc.) shall be stored in the storage device with electrostatic shielding effect;
2. Electronic components that are sensitive to magnetic field but have no magnetic shielding shall be stored in the storage device with the function of shielding magnetic field;
3. The mechanical and electrical components of the oil seal shall keep the oil seal intact.
3. Determination of the limited storage period of electronic components: the limited storage period of electronic components shall be in accordance with the appendix
3、 Limited storage life of electronic components:
The appropriate temperature and humidity parameters for storage of electronic components at different levels are also different. Storage temperature and humidity value of Class A device: 15-25, 25% - 60% RH; The storage temperature and humidity value of Class B device is: - 5 -+30, 20% - 75% RH; The storage temperature and humidity value of Class C device is: - 10 -+40, 10% - 80% RH.
4、 Storage requirements for electronic components:
1. The electronic warehouse is required to have an anti-static floor, and the personnel must wear anti-static clothes and anti-static bracelets according to the anti-static requirements;
2. It is required to store the flammable and explosive articles in different areas according to their categories. Appropriate isolation measures are required for flammable and explosive articles. For articles with special requirements, there should be obvious warning signs or safety signs;
3. The materials shall be placed in order, and the contents of the material storage card shall be standardized, so that the account, material and card are consistent;
4. Articles shall not be stored directly on the ground, but shall be protected by pallet or shelf;
5. The stacking of materials shall be small at the top and large at the bottom, light at the top and heavy at the bottom. One pallet can only place the same kind of materials. If the stacking height has special requirements, it shall be stacked according to special requirements, but the maximum height shall not exceed 160cm;
6. Refer to relevant specifications for storage of bulk materials, coiled materials and articles with special requirements;
7. For items with anti-static requirements, the following methods must be selected according to the actual situation: put them into anti-static bags and anti-static moisture-proof cabinets for storage.
5、 Raw material protection requirements:
1. The requirements of dust prevention and moisture prevention shall be fully considered for electronic components;
2. For vacuum packed PCB optical boards, ICs, etc., they should be well packaged, and the copper foil and pins should not be directly exposed to the air to prevent product oxidation;
3. Please protect special raw materials according to their requirements;
4. For components with pins, especially IC and other components whose pins are easy to deform, the original packaging form shall be used during packaging to avoid inconvenience or even inability to operate due to component pin deformation.
The storage of electronic components has strict requirements on environmental temperature and humidity parameters, such as:
(1) Integrated circuit: The harm of humidity to the semiconductor industry is mainly shown in that humidity can penetrate IC plastic packaging and invade IC interior from cracks such as pins, resulting in IC moisture absorption.
Water vapor is formed in the heating link of the SMT process, and the pressure generated causes the IC resin package to crack, and oxidizes the metal inside the IC device, leading to product failure. In addition, when devices are welded on PCB, the release of steam pressure will also lead to faulty soldering.
According to IPC-M190 J-STD-033 standard, SMD components exposed to high humidity air must be placed in a low humidity moisture-proof cabinet below 10% RH for 10 times of the exposure time to restore the "workshop life" of the components, so as to avoid scrapping and ensure product quality.
(2) Liquid crystal devices: Although the glass substrates, polarizers and filters of liquid crystal devices such as liquid crystal displays need to be cleaned and dried in the production process, they will still be affected by moisture after cooling, reducing the qualification rate of products. Therefore, it should be stored in a dry environment below 40% RH after cleaning and drying.
(3) Other electronic devices: capacitors, ceramic devices, connectors, switching devices, solders, PCBs, crystals, silicon wafers, quartz oscillators, SMT adhesives, electrode material adhesives, electronic pastes, high brightness devices, etc., will be harmed by moisture.
(4) Electronic components during operation: IC, BGA, PCB, etc. from semi-finished products in packaging to the next process, before PCB packaging and after packaging to power on, after unpacking but not used up; Devices waiting for soldering in the tin furnace, devices to be heated after baking, and unpacked finished products will be harmed by humidity.
(5) Finished electronic complete machine: It will also be harmed by humidity during storage. If it is stored in a high humidity environment for too long, it will lead to failure. For computer board CPU, it will lead to oxidation of gold finger, which will lead to poor contact failure.
In general, the preservation of components is very important. It must be packaged well and kept away from high temperature, high humidity and chemical corrosion environment.