Industrial application of static electricity products

In addition to static electricity products are widely used in more and more industries.
semiconductor
In the semiconductor device manufacturing plant, the yield of ICs, especially VLSI, is greatly reduced due to the adsorption of dust on the chips. IC production plant operators wear clean work clothes. If the human body is electrostatically charged, dust and dirt are easily adsorbed. If these dust and dirt are brought to the operation site, the quality of the product will be affected, the performance of the product will deteriorate, and the Ic will be greatly reduced. Yield. If the radius of the adsorbed dust particles is larger than 100 μm and the line width is about 100 μm, the thickness of the film is 50 μm, which makes it easier to scrap the product.
Therefore, it is necessary to establish an electrostatic protection system during the process of IC manufacturing and packaging. The IC package production line has stricter requirements for static electricity. In order to ensure the normal operation of the production line, the anti-static building materials are completely renovated in their clean workshops, and all personnel working in and out of clean workshops are equipped with anti-static clothing and other hardware measures. The packaging companies can comply with relevant national standards and the actual conditions of the company. Condition the company's standards or specific requirements for anti-static electricity to match the normal operation of the IC packaging production line.

photoelectric
It is well known that LED is a semiconductor product. In the actual production process, the direct contact and indirect contact between the human body and related components generate static electricity, if the voltage between two pins or more of the LED exceeds the dielectric breakdown strength of the component. , it will cause damage to the components. The LED of the LED display is a diode composed of a PN junction. Breakdown between the emitter and the base causes the current gain to drastically decrease. After the LED itself or each IC in the driving circuit is affected by static electricity, the function may not appear immediately. Sexual damage, but these potentially damaging components are usually shown during use and can have a fatal effect on the life of the display. Therefore, it is necessary to prevent the generation of static electricity. It is recommended that: Assembler should wear anti-static clothing (such as anti-static clothing, hats, shoes, fingertips, or gloves), and wear an anti-static wrist strap (the wrist strap must be connected to the grounding system quickly. Electrostatic Dissipation on the surface or inside,); assembly table (workbench) need to use anti-static table mat, and ground; dressed LED need to use anti-static component box; soldering iron, cutting machine, tin furnace (or automatic reflow equipment) Also need to ground. LED packaging bags and semi-finished packaging materials should use anti-static sponge or packaging.
electronic
1. The Source of ESD and its Damage After two different materials are rubbed, one carries a positive charge and the other carries a negative charge, creating a certain voltage between the two. The magnitude of the voltage depends on the nature of the material, the dryness of the air, and other factors. If an electrostatically charged object is placed close to a grounded conductor, there is a strong momentary discharge, which is called ElectroStatic Discharge. In general, an electrostatically charged object can theoretically be simply modeled as a small capacitor that is charged to a very high voltage. When the integrated circuit (IC) is subjected to ESD, the resistance of the discharge loop is usually very small, and it is not possible to limit the discharge current. For example, when an electrostatically charged cable is plugged into a circuit interface, the resistance of the discharge loop is almost zero, which causes up to tens of amps of instantaneous discharge spike current to flow into the corresponding IC pin. A momentary high current can severely damage the IC, and the locally heated heat can even melt the silicon die. Damage to the IC by the ESD generally also includes the internal metal connections being blown, the passivation layer being destroyed, and the transistor cells being burned. ESD also causes the IC's deadlock (LATCHUP). This effect is related to the activation of thyristor-like structural units inside the CMOS device. The high voltage can activate these structures, forming a large current path, typically from VCC to ground. The latch current for serial interface devices is typically 1 amp. The lock-up current will remain until the device is powered down. But then, ICs are usually already burned by overheating. For a serial interface device, ESD will cause the IC to malfunction, communication errors, and severe damage. To analyze the fault phenomenon, MAXIM conducted ESD tests on RS-232 interface devices from different manufacturers. As a result, it has been found that there are two common types of fault phenomena: one type of fault phenomenon is crosstalk, and the signal received by the signal receiver interferes with the transmitter and causes bit errors (see Figure 1). Another type of fault is the formation of a reverse current path inside the IC that allows the RS-232 signal level (±10V) received at the receiver port to be fed back to the power supply (+5V). If the power supply does not have a voltage-regulating function that absorbs current, an excessively high feedback voltage can damage other devices powered by a single power supply (+5V). For the serial interface device, the simplest protection measure is to apply a resistive element to each signal line. . Series resistors can limit the peak current, and capacitors connected in parallel can limit the instantaneous spike voltage. This has the advantage of low cost but limited protection. Although the destructive power of ESD can be suppressed to some extent, it still exists. Because the RC element does not reduce the peak voltage spike, it merely reduces the slope of the voltage ramp. Moreover, RC components can also cause signal distortion, which limits the length of the communication cable and the communication speed. External resistors/capacitors also increase the board area. Another widely used technique is an applied voltage transient suppressor or TransZorbTM diode. This protection is very effective. However, the additional devices will still increase the board area, and the capacitance effect of the protection device will increase the equivalent capacitance of the signal line, and the cost is also higher because the TransZorbTM diode is more expensive (approximately 25 cents per each), typically 3 rounds. The /5 received COM port requires 8 TransZorbTM diodes for up to $2. An effective ESD test should be performed over the entire voltage range within the highest test voltage. Because some ICs may pass the test at 10kV, they are destroyed by ESD at 4kV. Such an IC has virtually no antistatic capability. The human body model and the IEC1000-4-2 standard stipulate that 200V intervals must be tested within the test voltage range, and positive and negative voltages must be tested at the same time. That is, starting from ±200V, ±400V, ±600V, up to the highest test voltage. All possible operating modes of the IC should be separately tested for complete ESD. Including the power-on state, power-off shutdown state, if the serial interface device automatically shuts down the sleep mode, it should also perform an ESD test for this state. All relevant test standards and procedures stipulate that, at each test voltage point, the pin under test shall be discharged 10 times continuously. Considering the positive and negative voltages must be measured, the actual discharge shall be 20 times. After each round of discharge is completed, the corresponding parameters of the device under test shall be measured to determine if the device is damaged. For the serial interface device (RS-232, RS-485), the following criteria should be followed: ● The power supply current is normal (increased supply current generally means that a deadlock of the device has occurred); ● The output level of the signal transmission output is still Parameter specification range; ● The input resistance of the signal receiving input is normal (usually between 3kΩ and 7kΩ). Only when these indicators are qualified, can we go to the next voltage test point. After all the voltage points have been tested, The IC should also perform a full functional test and measure whether each parameter of the IC is still within the range defined by the parameter standard.Only the ICs that can meet the specified parameter standards after all these ESD tests are real antistatic ICs. The ESD test is done according to the general standard, but it cannot judge the quality of the IC.Some ESD testers come with some parameter measurement functions, but since they are not measured for the parameters of a specific device, they are just general testing methods, and therefore only As a reference, rigorous testing should still be conducted in accordance with the test procedures and test criteria described above.
medicine
In the pharmaceutical production process, due to friction, there is a large amount of static electricity in the medicines or pharmaceutical vessels, which leads to the adsorption of dust in the air, affecting the quality and pass rate of the products. Therefore, drug production and cleaning of drug vessels The process must be effective to eliminate static electricity, and from the improvement of product quality. For the pharmaceutical industry, to improve the quality of the product, the dust on the product must be eliminated. However, the dust is adsorbed on the surface due to static electricity. Therefore, it is necessary to eliminate static electricity before the dust is removed. The more common equipment is: in addition to electrostatic ion gun, in addition to electrostatic ion nozzle, in addition to static ions, etc.