Brief introduction of microelectronics ESD protection
In recent years, with the rapid development of China's economy and the continuous improvement of the technical level of China's information industry, polymer materials and microelectronic devices have been widely used in various fields and their products. ESD is the main threat to microelectronic devices. ESD seriously affects the quality of microelectronic devices and threatens the overall operation of the devices. In order to protect microelectronic devices, it is necessary to protect electronic devices from static electricity from the aspects of design, production and transportation.
ESD (Electrostatic Discharge) stands for "Electrostatic Discharge". Static electricity refers to the excess or deficiency of the relative electrostatic charge on the surface of an object, which may be positive or negative. Due to "surplus" or "shortage", the static charge is in an unbalanced state and is easily transferred.
ESD includes four stages. The first stage is the generation of electric charge. The generation of electric charge is caused by friction or induction. This process is called electrostatic charging. The second stage is charge transfer. The transfer of charge is due to the potential difference between two objects. When the potentials of the two objects are balanced, the charge transfer stops. The third stage is charge accumulation. Static charge can be weakened by neutralization or leakage. When the electrification speed is greater than the decay, the charge will accumulate. For example, when the human body is insulated from the earth, the electrostatic charge of the human body can be as high as 1.5KV-35KV. The fourth stage, quick release. Objects with different electrostatic potentials cause electrostatic charge transfer between objects due to direct contact or electrostatic induction, also known as electrostatic discharge. This is a phenomenon in which the electrostatic field energy reaches a certain level and discharges. It may also be caused by the conduction of charged ions in the air to form a current between two objects, resulting in a small avalanche effect.
Four ESD protection directions
Operator: People are the biggest source of static electricity. People generate static electricity when walking and working, and they may generate static discharge when they touch or approach microelectronic devices. To reduce the personnel factor, you must wear anti-static clothing, gloves and anti-static shoes, wear anti-static bracelets/anklets, and be grounded reliably. Develop good working habits and stay away from static sensitive products without anti-static measures or imperfect measures.
Equipment: In order to improve the production capacity of enterprises, many processes use automated equipment. The operation of these equipment will generate a lot of static electricity. During the processing of microelectronic devices, various processes will release static electricity, and a large number of microelectronic devices will fail. All equipment, instruments, operating tables, stools and shelves need to be reliably grounded. Moving rotating trolley etc. It should also be connected to the ground by installing an electrostatic discharge device.
Material: The countertop and turnover box/packing box are made of antistatic/conductive materials in the operating environment.
Environment: The generation of static electricity is directly proportional to the environmental humidity, that is, the higher the humidity, the less static electricity is generated. However, high humidity environments can easily lead to rust and corrosion. Considering comprehensively, the humidity in the electronics production workshop is generally maintained at 30%-70%RH. In addition, ion fans can also be used to neutralize static charges.