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Anti-static role and significance

Why in the manufacturing process to take measures to control anti-static? We have the following three aspects of what I mean. 

A majority of the electronic components are sensitive to static electricity device 

Most of unprotected ESD sensitive components are very low, many hundreds of volts in scope, such as the one-tube-MOS in the 100-200V between, GaAs FET in the 100-300V, and these are one-tube Can not increase the protection of the circuit; some of the circuits in particular has taken Electrostatic CMOS IC design protection, although improved to the level of anti-ESD, but most can only achieve 2000-4000V, and in the actual environment of generated electricity voltage may be To reach tens of thousands of volts (for example, Chapter 1 of the Table 1.4 and Table 1.6. Therefore, there is no protection of the components are vulnerable to static electricity damage. With the components and reduce the increasing size of such damage will be more and more . So we said, is a static sensitive components overwhelming majority of devices, the need to manufacture, transport and use of anti-static process to take protective measures. Table 2.1 lists some static devices designed to protect sensitive to electrostatic discharge. 

2, the electronics industry caused by static electricity on the great loss 

The electronics industry, such as microelectronics, optoelectronics and manufacturing companies to use because the losses caused by static electricity and is a very serious hazard. According to the United States in 1988 reported that their electronics industry, due to the impact of ESD, the annual loss of up to 50 billion dollars; According to Japanese statistics, they are not up to standard electronic devices in 45 percent due to static electricity caused; China Each year as a result of electrostatic hazards caused by the loss of at least tens of millions. Figure 2.1 in the United States Ti companies in a particular year to customers the reasons for device failure analysis of the outcome of the survey, which can be seen by the EOS / ESD failure caused 47% of the total; Figure 1.2 in the United States semiconductor reliability of the information in 1993 from Manufacturers, testing and use have been the scene of the 3400 case of failure to carry out the statistical case, from which we can see, EOS / ESD also caused by the failure to reach 20%. Figure 2.3 and is a CMOS device and a bipolar device in the ESD by the injury looks like a chip inside. ESD electronic components for the harm is also reflected in its potential. That is, in the device by the ESD stress is not immediately after the failure, and will be used in the process of the gradual degradation or sudden failure. At this time the device was "the work of injuries." This is the people's awareness against the static one of the main reasons not enough. In fact, the ESD components of the potential damage and the cumulative effect will seriously affect the reliability of the use of the components. Due to the potential damage of the device can identify and remove, once in the application of machine failure, resulting in even greater losses. And to avoid or minimize this loss is the best way to take the static electricity protection measures to prevent electrostatic discharge components of the hazards. Figure 2.4 is a device by the ESD potential damage example, the devices did not function failure, but a pin of the IV characteristics have been some changes. Figure 2.5 is a model of the two sets of CMOS IC reliability of the comparison tests carried out. Is a group of experienced failure of its low threshold voltage of the ESD more tests and completely normal function of the sample, and the other group is not subject to any test of the Good. Test results of the life of the former, the median life expectancy (cumulative failure rate of 50% of life) less than 2 months over magnitude. This fully shows that the potential damage to the ESD device reliability. 

3, the situation of domestic and foreign enterprises 

In the international arena in 1979 set up the EOS / ESD Research Association, the main electronics industry EOS and ESD problems and seek solutions. MIL 883E "micro-circuit test methods" on the evaluation of the level of ESD standards have been amended 7 times, it is now version 3015.7, and a lot of criteria microcircuit clear that the military must be 2kV of ESD level. Most of the major U.S. electronics manufacturers in the early 1980s have established their ESD organization dedicated to ESD work, mainly in anti-static design, static testing, static electricity protection and management, training and so on. And the international community developed countries, China in this regard started a lot later, the gap is also large. Until recently, only a few years and really developed. In the military, such as the revised version of the GJB GJB548A-96 and GJB 128A-97 respectively, an increase of micro-circuits and discrete devices sensitive to electrostatic discharge classification requirements; and called for implementation of the National products must be given the value of the ESDS ; In products for civilian use, the joint venture and wholly owned enterprises in a better situation, the earlier start, most of the foreign enterprises in the light of the practice in the design and ESD anti-static protection have reached a higher level, such as the Shanghai Beiling, Nanjing Fujitsu Guangdong Nortel, and so on; and other civilian enterprises have realized the importance of static electricity problems, and anti-static product design and production of static electricity protection and investment funds, to obtain good results. While domestic enterprises are gradually improving, but there are still a large gap. For example, military products, such as CMOS circuitry has not yet made the request 2kV; some production lines luxury decoration, but no anti-static measures; lack of workers on the ESD job training.