Harm of electrostatic voltage on semiconductor and IC production lines
1. Electrostatic voltage on semiconductor and IC production lines
1 wearing nylon clothes, plastic base shoes slowly moving on the clean floor, the human body will bring 7KV-8KV voltage
2 When the crystal carrier made of glass fiber slides over the polypropylene table, it is easy to generate 10KV static electricity.
3 wafer assembly line: wafer 5KV, wafer loading box 35KV, work clothes 10KV, desktop 10KV, plexiglass cover 8KV, quartz crystal 1.5KV, wafer tray 6KV
4 lithography plastic floor 500V-1000V, metal grid floor is also 500V-1000V, diffusion room plastic floor 500V-1500V tile floor is also 500V-1500V, plastic wall surface is about 700V, plastic ceiling 0-1000V, aluminum plate air outlet, back Air outlet 500V-1000V, metal movable leather chair surface 500V-3000V
2. Electrostatic hazards on semiconductor and IC production lines
1 Hazard of electrostatic Coulomb force: Dust and dirt adsorbed by electrostatic Coulomb force may bring components, which may cause leakage or short circuit, which may impair performance and greatly reduce the yield. If the particle size of the dust is >100 μm, the width of the aluminum wire is about 100 μm, and the thickness of the film is less than 50 μm, the product is most likely to be scrapped. This happens mostly in the processes of corrosion cleaning, photolithography, spot welding and packaging.
2 Hazard caused by electrostatic discharge: If there are thousands of tens of thousands of volts of high-potential objects, pulse-shaped discharge or spark discharge, when there is a very high discharge current flowing to the earth, a pulse-like current peak is formed at 20A. , causing considerable impact, electrostatic discharge (ESD) is also accompanied by electromagnetic wave emission, which will cause various hazards.
A, MOSIC and other semiconductor devices will be electrostatically discharged (ESD) breakdown or half breakdown. The gate of the MOS field effect transistor is taken out from the oxide film, and an oxide film is interposed between the gate and the substrate. When the voltage between the gate and the substrate exceeds a certain value, the oxide film is broken down, if MOSIC, Then all are scrapped. When the voltage is applied to UB=50-100V, the oxide film will be broken down because the gate capacitance is very small (about a few picofarads), and the input resistance is very high (about 1014Ω or more). A small amount of charge will generate a very high voltage, and the charge will be difficult to sink. As long as it is greater than 50V (no protection), it will burn out. Therefore, as long as the person touches the grid, the component will be broken, because it is common for people to charge more than 50V. .
We can understand the sensitivity of integrated circuits to static electricity. The difference between various chips is that they can withstand different static voltage values. In practical conditions, a static voltage of almost 20V directly contacts the device to destroy or degrade performance.
Electrostatic discharge damages components to make the entire printed circuit board useless, resulting in economic losses;
The noise of electrostatic discharge causes the malfunction or malfunction of the equipment and the indirect discharge. The result of the capacitor discharge measurement, in addition to generating a large pulse of transient current, also produces strong noise across several megahertz or even hundreds of hertz. In recent years, basic research on computer malfunction caused by electrostatic discharge noise has made great progress.
When electromagnetic waves generated during discharge enter the receiver, noise is generated, which interferes with the signal to reduce the quality of the information or cause information errors.
3, the danger of electrostatic induction
The object induced by static electricity is completely equivalent to the charged body, and there are electrostatic phenomena and discharge phenomena. If the resistance of the sensing object is a small good conductor, spark discharge will occur and cause harm.
A. In the workshop of production operation.
In the vicinity of high-voltage equipment and lines, when personnel operate welding, MOS devices or MOSSI, due to electrostatic induction, it is easy to cause electrostatic discharge of the human body to the device, thereby damaging the device.
B. Air conditioning airflow (ion flow) transported by the pipeline is equivalent to charging when the human body blows. When the human body is in contact with sensitive components, the electrostatic discharge will break down the damaged device.
4. Electrostatic hazard to the production process of electronic equipment
All aspects of the production of the machine will suffer from electrostatic damage. The main links include: procurement and transportation of devices; inspection and acceptance of devices into the factory; storage and picking of devices; device insertion and soldering; product assembly and inspection; product packaging and delivery.
In addition to the destruction of static electricity during the production of electronic components and electronic equipment, it is also subject to static electricity during the use of the product. In summary, the damage caused by static electricity is enough to cause the performance of electronic devices and electronic devices to be out of tune, and the damage to electronic devices and devices cannot be ignored.