In the world of semiconductor device production, the yield for IC, especially VLSI, can be severely inhibited by dust adsorption on the chips. The operators in an IC production workshop need to wear clean work clothes, because if the human body has the electrostatic energy it can very easily adsorb dust, dirt, etc. If the dust and dirt were taken to the operating site it would affect the quality of the products, thereby degrading product performance and reducing IC yield greatly. This is especially true If the radius of the adsorbed dust particles is greater than 100 μm and the width of the particle is about 100 μm. The thickness of the film will be easier to remove if it’s under 50 μm.
Therefore, it is necessary to establish an electrostatic protection system in the processing and packaging of IC, with the IC packaging production line being the most stringent. In order to guarantee the normal operation of the production line, the entire building must be constructed of antistatic materials, all personnel in and out of the clean workshop must be equipped with antistatic clothing, any hardware, such as packaging, has to follow the national standard and ideally the hardware company will develop enterprise standards and specific requirements in terms of antistatic, to better facilitate the normal operation of an IC packaging production line.
LED
As everyone knows, LEDs are a semiconductor product, whose main use in the production process involves the human body and the related components coming in direct and indirect contact with static electricity. If the LED voltage is two or more stitches over the element dielectric breakdown strength, it will cause damage to the components. An LED display is composed of P-N junction diodes. LED emitters and the base can make the breakdown between currents gain sharply lower by itself or in the drive circuit of each IC after being affected by static electricity. The functional damage may not appear immediately, but the potential damage of components used in the process can have a fatal influence on the life of the screen.
This is why it is necessary to prevent electrostatic generation. Suggestions on how to accomplish that include: having the assembly operators wear antistatic clothing (such as antistatic shirts, hats, shoes, gloves, etc.) as well as antistatic wristbands (wristbands must be connected to a ground system), the assembly table should be made of a static radio pad, and grounded, the holding of LED requires the use of antistatic components, the soldering iron, cutter, tin furnace (or automatic reflow soldering equipment) should also be grounded. LED packaging and semi-finished packing materials should be used for antistatic sponges or packaging.
Electronics
Sources of ESD and its hazards
When two different materials are rubbed together, one having a positive charge and the other having a negatively charged, they generate a certain voltage between them. The size of the voltage depends on the nature of the material, the dryness of the air, and other factors. If an object with static electricity is close to a grounded conductor it produces a strong instantaneous discharge, which is the electrostatic discharging. In general, electrically charged objects can in theory be simply modeled as a small capacitor charged to a high voltage. When the integrated circuit (IC) is subjected to ESD, the electrical resistance of the discharge circuit is usually small and unable to limit the discharge current. For example, when an electrically static cable is plugged into the interface of a circuit, the resistance of the discharge circuit is almost zero, which will result in the instantaneous discharge spike current flowing into the corresponding IC tube feet as high as dozens of amps. A sudden large current can seriously damage an IC; local heat will even melt the silicon chip core. The damage of ESD to IC can include the internal metal connections being burned, the passivation layer being destroyed, the transistor unit being burned, and so on.
The ESD also causes IC’s deadlock (LATCHUP). This effect is related to the activation of similar silicon controlled structures in CMOS devices. High voltages can activate these structures and form large current channels, usually from the VCC to the ground. The locking current of serial interface devices is generally 1 ampere. The locking current will remain until the device is out of power. By then, however, IC has often been burned down by overheating.
Medicine
In pharmaceutical production processes, because of the friction of the components used in the production of medicine, there is a lot of static electricity. This causes dust particles in the air to be adsorbed to the medicine, affecting the quality of the product and percentage of loss. So in the process of drug production and facility cleaning, great efforts must be made to eliminate static electricity. For the pharmaceutical industry to improve, the quality of their product they must eliminate dust, but the dust is due to the electrostatic adsorption, so to remove the dust they must first eliminate static electricity. The most common equipment used for this are electrostatic ion air gun, electrostatic ion wind aperture, electrostatic ion rod, etc.
Printing
Printing is carried out on the surface of objects, and electrostatic phenomenon also mainly occurs on the surface of objects. The relationship between the two is very close. The process of printing involves frequent collisions, frictions, and contacting liberations, which means almost all objects involved in the printing process carry static electricity. First is the charge of the substrate surface, such as paper, polyethylene, polypropylene, cellophane, adsorption confetti, or just the dust in the air, impurities, etc., which can affect the ink transfer, reduce the ink transfer rate, cause slippage due to the surface and the ink repelling each other.
Next is the ink charge, if the ink has a charge and is on the edge of the line it is possible to have an “ink beard.” In addition, the ink will also fog due to the charge, causing serious pollution of the print and printing environment. Charged substrates may even happen, with severe air discharge caused by ultra-high voltage creating electric shock or fire. High-speed printing presses, because of the large friction function of the high speed, produce a lot of static electricity. Electrical devices have an imperfect elimination than old paper rotary presses at high speeds. Some locations can have a voltage of up to 15000 V, with a current of about 100 μA. Such a powerful voltage and current for the printing process is complicated and the possibility of harm is quite serious, especially the direct threat to the personal safety of the operators. When printing, we use electrostatic eliminators to reduce static electricity. Commonly used products in static elimination for printing machines are the high-frequency induction type electrostatic eliminator, voltage electrostatic eliminator, power frequency high voltage electrostatic eliminator, installation time placed near the drum.
Textile
In ordinary textile production and processing, electrostatic induction is common due to friction and the low moisture of common synthetic fiber products. The accumulation of electrostatic charges can easily cause dust adhesion, produce discomfort, and can cause an increase in blood pH, lower blood calcium levels, increased calcium content in the urine, high blood glucose, and low vitamin C levels. A higher static voltage can even give an electric shock to the body. Ion bars can be used to quickly remove the high static electricity on the surface of a textile. We can customize different functions and types of ion bars according to the production environment of customers, and better meet the needs of customers to solve static problems.
Spray Paint
Since most coatings are diluents of various flammable solvents, the static electricity generated when spraying can very easily ignite the gases of these solvents. Therefore, controlling the electrostatic hazard in coating spraying is an important problem. In order to prevent the effects of electrostatic in paint spraying the device is equipped with static electricity inhibitors. Spraying construction personnel should wear antistatic work shoes with a resistance of 10^5 ~ 10^8, they must not wear insulating work shoes. They should try to prevent paint from getting on the ground or on the back of the coating, and should not use insulating materials such as plastic plates, but instead plates made of conductive materials.
Plastic
Plastics are all polymer materials, the surface resistance and volume resistances are more than 10^12. Therefore, the good insulation properties of plastic materials are a given. Because of this reason, in addition to the way it is processed (handling, contact, separation, friction, collision) it is prone to static electricity. Some of this static electricity production cannot be avoided, but an effective prevention method is to add a moisture absorption effect that is harmless to plastic materials, to reduce its surface resistance. This is the plastic antistatic agent, with different options depending on the type of plastic.
