What is the hazard of static electricity to IC packaging
What is the hazard of static electricity to IC packaging? First of all, the cause of static electricity can be seen everywhere. With the rapid development of science and technology and the high degree of automation in industrial production, the hazards of static electricity in industrial production are already obvious. It can cause various obstacles, limit the improvement of the level of automation and affect product quality. Here are the main reasons for the generation of static electricity in combination with the actual situation of our factory in the integrated circuit packaging and production process.
1. High-resistance materials are mostly used for construction and decoration materials in production workshops
IC production process requires the use of clean workshop or ultra-clean workshop. The particle size of dust-removing particles is required to be changed from the previous 0.3μm to 0.1μm, and the density of dust particles is about 353 particles/m3. To this end, in addition to the installation of various dust collection equipment, inorganic and organic dust-free materials must be used to prevent dust. However, the electrical performance of building materials is not considered as an indicator. There is no provision in the design specifications for clean workshops of industrial enterprises. The interior decoration materials mainly used in the clean workshop of IC factory are: polyurethane elastic floor, nylon, hard plastic, polyethylene, plastic wallpaper, resin, wood, white porcelain plate, enamel, plaster and so on. Most of the above-mentioned materials are polymer compounds or insulators. For example, the resistivity of plexiglass body is 1012~1014Ωcm, and the resistivity of polyethylene body is 1013~1015ncm. Therefore, the conductivity is relatively poor. Static electricity due to some reason is not easy to leak to the earth through them, which causes the accumulation of static electricity.
2, human body static electricity
The different actions and walking back and forth of the operators in the clean room, the soles of the shoes and the ground are constantly in close contact and separation, and various parts of the human body are also active and friction. Whether it is fast walking, slow walking, or trotting, static electricity will be generated, which is the so-called walking charge; the human body stands up after moving. , The work clothes worn by the human body and the chair surface are separated after contacting the chair surface, and static electricity will also be generated. If the electrostatic voltage of the human body cannot be eliminated and the IC chip is touched, it may cause IC breakdown unknowingly.
3. Static electricity caused by air conditioning and air purification
Since IC production requires 45-55% RH, air conditioning must be implemented and air purification must be performed at the same time. The dehumidified air is sent to the clean room through the primary filter, medium efficiency filter, high efficiency filter and air duct. Generally, the wind speed of the main air duct is 8~10m/s, and the inner wall of the air duct is painted. When the dry air and the air duct, the dry air and the filter move relative to each other, static electricity will be generated. It should be noted that static electricity is more sensitive to humidity. In addition, the transportation of semi-finished products and IC products will generate static electricity during packaging and transportation, which is one of the factors of static electricity.
Secondly, static electricity is very harmful to IC. Generally speaking, static electricity has the characteristics of high potential and strong electric field. In the process of electrostatic charging and discharging, transient high current discharge and electromagnetic pulse (EMP) are sometimes formed, generating electromagnetic radiation fields with a wide spectrum. In addition, compared with conventional electric energy, electrostatic energy is relatively small. In the natural electrification-discharge process, electrostatic discharge (ESD) parameters are uncontrollable, and it is a random process that is difficult to repeat. Therefore, its role is often affected by people. Ignored. Especially in the field of microelectronics technology, the harm it causes to us is astonishing. According to reports, the direct economic loss caused by static electricity is as high as several hundred million yuan every year. The harm of static electricity has become a major obstacle to the development of the microelectronics industry.
In the semiconductor device production workshop, due to the adsorption of dust on the chip, the yield of ICs, especially very large-scale integrated circuits (VLSI), will be greatly reduced. Operators in the IC production workshop wear clean overalls. If the human body is charged with static electricity, it is easy to absorb dust and dirt. If these dust and dirt are brought to the operation site, it will affect product quality, deteriorate product performance, and greatly reduce Ic. Yield. If the radius of the adsorbed dust particles is greater than 100 μm and the line width is about 100 μm, when the film thickness is below 50 μm, the product is most likely to be scrapped.