The harm of static electricity to electronic components and the principle of protection
According to different types of electronic components, the degree of electrostatic damage is also different, and the lowest static voltage of 100V will also cause damage to them. In recent years, as the development of electronic components tends to be integrated, the corresponding electrostatic voltage is also continuously reduced.
The electrostatic voltage induced by the human body is generally above 2-4KV, which is usually caused by slight movements of the human body or friction with the insulator. In other words, if the electrostatic potential in our daily life comes into contact with ICs, almost all ICs will be destroyed. This danger exists in any working environment where no electrostatic protection measures are taken. The damage of static electricity to IC is not only reflected in the manufacturing process of electronic components, but also in the process of IC assembly and transportation.
To solve the above problems, you can take the following various electrostatic protection measures:
1. Electrostatic protection at the operation site. Devices that are sensitive to static electricity should be operated in an anti-static work area;
2, human body electrostatic protection. Operators wear anti-static overalls, gloves, working shoes, working hats, and wrist straps;
3. Electrostatic protection during storage and transportation. The storage and transportation of electrostatic sensitive devices cannot be carried out in a charged state.
To achieve the above-mentioned functions, the basic method is to try to reduce the voltage of the charged object to reach the safety value required by the design. That is, the charge (Q) and resistance (R) in the following formula are required to be small, and the electrostatic capacity (C) to be large.
V=I.R
Q=C.V
where V: voltage, Q: electric charge I: current C: electrostatic capacity R: resistance
Of course, the resistance value is not as low as possible, especially in the anti-static area of a large area where safety measures such as leakage must be considered before selecting materials. Electrostatic protection measures
Inspect and install IC static electricity protection workplaces. The purpose of anti-static measures in this process is to keep the workplace including the human body at the same potential. The specific methods are as follows:
1. Connect the 1 megohm resistor to the ground, and wear an anti-static wrist strap to operate;
2, ground the tester, tools, soldering iron, etc.;
3. Ground the work surface after laying anti-static mats;
4. Operators wear anti-static work clothes and work shoes;
5. Anti-static floor or conductive rubber floor mat on the ground;
6. The IC should be kept at the same potential during transportation and packaging.
Anti-static performance test cycle and precautions
Anti-static rubber sheet (table mat, floor), anti-static work shoes, anti-static work clothes, anti-static turnover container, etc. should be tested at least once a month. Anti-static wrist straps, air guns, fans, instruments, etc. should be tested once a day. When testing, factors such as the temperature and humidity of the tested location must be considered.