Safe operation of electrostatics in workshops
Electrostatic protection is largely a matter of raising awareness of electrostatic protection. The level of electrostatic knowledge of all personnel who come into contact with electrostatic sensitive devices has been improved, so it is very important to carry out electrostatic safety operation and electrostatic protection technology education. The US military standards and my country's standards have clear provisions including six aspects, including electrostatic protection grounding, electrostatic protection of personnel and electrostatic protection equipment in the site environment, and daily maintenance of electrostatic detection instruments and protective measures.
1. Electrostatic protection grounding
The anti-static system must have an independent and reliable grounding device. The grounding resistance should generally be less than 10 ohms. The burial and detection methods should comply with the requirements of GBJ79: the anti-static ground wire shall not be connected to the power supply neutral line and shall not be shared with the lightning protection ground wire. Use a three-phase five-wire power supply, and its large ground wire can be used as an anti-static ground wire (but the neutral ground wire shall not be connected)
2. Electrostatic protection of the site environment
The ground, walls and ceiling of the anti-static work area should be made of anti-static materials according to national standards to have good anti-static performance. Ordinary insulating materials are prohibited.
3. Static electricity protection for personnel
The human body can generate static electricity with a voltage of tens to tens of thousands of volts in daily activities and production operations, and the discharge process is extremely short, so the energy released during the discharge process can reach tens of watts, which is enough to cause the micro-area of the chip to burn or the SiO2 film to break down. Therefore, personnel entering the anti-static work area should be equipped with anti-static clothing and anti-static shoes for electrostatic protection, and equipment maintenance personnel should also be equipped with anti-static wristbands.
4. Static electricity protection for equipment
Anti-static safety workbench is a basic component of the anti-static work area. It consists of anti-static table mats, wristband connectors and grounding wires. Plastic, rubber, cardboard, glass and other debris that are prone to static electricity are not allowed to be stacked on the anti-static safety workbench. Drawings, materials, etc. should be placed in anti-static document bags. Seat cushions should be conductive and connected to static grounding. If necessary, the workbench is equipped with an ion wind static eliminator, and anti-static floor mats can be laid under the seat. In the process of electronic equipment development and production, all containers for storing circulating static sensitive devices (SSD) should have electrostatic protection performance, and metal and ordinary plastic containers are not allowed.
5. Electrostatic detection instrument
Equipped with relevant electrostatic detection instruments to detect personnel equipment and various protective measures at any time or regularly to ensure the effectiveness of protection.
6. Daily maintenance of protective measures
Any anti-static measure is not a one-time solution. It needs to be properly maintained regularly in daily use to ensure that it is indeed effective in extending its service life and reducing costs.