How much influence does the ion fan have on static electricity?
“Ion fans give the same attention to the ESD performance and pollution control of products and equipment. The clothing and materials in the clean room* are made of static dissipative materials and can be grounded,” said RussMoulton, a non-silicon crystal industry leader.
Other industries, especially in the head drive industry, have adopted more clean room antistatic materials. In the past, the head drive industry used ESD control technology only in the production of ICs (chips, microchips). But now more industries have adopted ESD control technology.
Because of the impact of electrostatic discharge (ESD) on precision circuits and disks, the electronics industry faces enormous challenges. They will lose billions of dollars each year. A voltage of only 5V can damage tiny components, and voltages less than 100V can cause the entire electronic circuit to be scrapped.
In areas affected by ESD, clean room managers must consider the percentage of failures and damage caused by ESD on the production line.
However, ESD control materials are prone to contamination – static dissipative materials are a major source of dust particles and chemical contamination in cleanrooms. In order to control the ESD, the items in the clean room are composed of static dissipative materials that prevent ESD and electrostatic attraction. Choosing an anti-static ion blower for a clean room is a big challenge. However, ESD solutions are more complex than finding static dissipative materials.
Available technology
In the clean room, products designed for static dissipation: cotton swabs, wipes, glue, cloth, wall materials, wrist straps, gloves, work clothes, etc. can be used. However, static dissipative materials can also cause contamination, and many clean room products made of plastic or stainless steel may accumulate or conduct electricity.
Manufacturers of ESD products have had difficulty developing new static dissipative materials. The IC is getting smaller and the electrostatic sensitivity is also increasing. In the past three years, many electronics manufacturers have begun to demand more ion fan ESD products.
Finding the right antistatic raw materials is difficult. The mask is made of plastic and has excellent wear resistance, low volatiles and chemical resistance. It is a good material for clean rooms. It is difficult to find transparent raw materials. Additives and copolymers make the material opaque due to the composition of different refractive indices. Moreover, plastics must have good surface resistance.
Electrostatic adsorption
Decontamination becomes more difficult in the clean room due to the presence of static electricity. Dust particles are always easy to stick to the silicon wafer due to the action of static electricity, resulting in product damage and lower yield.
Our big problem is to find antistatic materials suitable for use in clean rooms. In the LCD industry, the glass substrate becomes larger and the ability to attract charges is also enhanced. Due to the large size of the substrate, any contamination may result in a decrease in the yield.
Like other pollution control industries, the LCD industry has been looking for new materials that can solve ESD problems. Materials used in cleanrooms are also more likely to use antistatic ion blowers, and new materials can be tried on cotton swabs and rags instead of traditional materials.
Suitable type
Why are there no suitable ESD products in the clean room? In the past three to five years, manufacturers have realized that ESD products are needed in clean rooms when providing products to clean rooms. However, finding an ESD product that can be used in a clean room is a problem. Because the performance of many ESD products used in clean rooms is not stable enough.
The big problem with ESD control in cleanrooms is the movement of people in the clean room. Because people wear a lot of polyester fabrics, they generate a lot of electric charge. The only way to remove this charge in a clean room is to ground.
In the past five years, it has been found that a garment system made of a mixture of carbon fiber and fabric provides clean room requirements for ISO 5 (Class 100).
Each part of the garment has the same electrical conductivity and has an electrically conductive connection from the hood to the sole. Persons working in a clean room can walk through the conductive sole without grounding when wearing such clothes, so that they are not limited by the length of the ground wire.
The emergence of such work clothes is a result of high demands on the product, which helps to reduce the low yield and high bad rate caused by ESD problems in the clean room.
There is no cheap and quick repair method for ESD ion fan control. The key is to control the ESD, such as a suspended laminar flow ion fan, or install an ion fan next to the material that needs to control ESD. As the size of the chip (IC) decreases, it becomes more sensitive to ESD. Now, the control of ESD is not limited to the protection of the working network, but also the control of the wafer and the personnel who produce the wafer. Many companies with high standards are controlling ESD like this.