Introduction to Antistatic ESD Textiles
The costs incurred by electronics and semiconductor manufacturers due to electrostatic discharge (ESD) and particulate contamination are staggering. Statistics show that the global annual cost of damage caused by ESD is estimated at $900 million, and some experts believe the actual losses are even higher. Therefore, the requirements and quality of environmental control rooms (clean rooms) are constantly increasing.
Because the air in clean rooms must typically be maintained at a relative humidity of 45%, static electricity is easily generated. Static electricity induces two main types of adverse effects in semiconductor processes: one is particulate contamination, ranking fifth among various clean room particulate contamination sources at approximately 5%; the other is electrostatic discharge (ESD), which causes the highest failure rate among early-stage product failures, exceeding 50%. To overcome the problem of ESD, many manufacturers have begun researching various static electricity control programs, including those addressing the hazards of static electricity generated by process equipment and the human body.
Antistatic protective clothing for cleanroom use must possess the following characteristics:
(1) Static electricity/static discharge
(2) Low chance of generating microparticles (low dust generation)
(3) Sufficient weave strength
(4) Good durability
(5) Resistance to specific chemical agents
(6) Comfortable to wear.
Currently, most antistatic cleanroom garments are woven from synthetic long fibers. These fabrics can be knitted, woven, or spunbonded. Polyester long fibers are currently the most important raw material for cleanroom fabrics. To give the fabric a durable antistatic/static discharge effect, conductive yarns (approximately 0.1-0.5% of the fabric weight) are typically embedded during the weaving process. These conductive yarns usually appear as stripes or grids (3-10 mm, depending on the end use) on the finished fabric.