A newly built 12 inch wafer fab is progressing, but project leader Johnny is troubled by difficulties in elevator procurement. Traditional commercial elevators have fatal deficiencies in cleanliness, vibration reduction, and environmental adaptability. A certain semiconductor factory once suffered losses of hundreds of millions of yuan due to a leak in the elevator door gap, causing the photomask to be contaminated with fine dust and a whole batch of wafers to be scrapped; Another time, due to the vibration of the traction machine affecting the lithography focus, the accuracy of 1200 wafers was incorrect, causing billions of yuan in losses again.
Limitations of Traditional Solutions
The design problems of conventional elevators are very prominent: the weld seam on the car wall is as wide as 0.1-0.5 millimeters, which is prone to dust accumulation; Friction during door opening and closing will release metal particles; The ventilation and filtration capacity is insufficient, causing the particle concentration in the carriage to far exceed the cleanroom standards. Vibration is the key bottleneck - the low-frequency vibration amplitude of the traction machine reaches 50 microns, the friction of the guide rail superimposes high-frequency vibration, and the rigid connection directly transmits the vibration to the load. The measured displacement even exceeds 800 times the allowable value of the lithography machine, and even installing shock absorbers is useless. Environmental issues are also frequent: ordinary stainless steel is prone to rusting, gaps leak and break indoor pressure differentials, and electromagnetic interference can also affect the accuracy of detection equipment data.
Three major innovative solutions
To address these challenges, Johnny's team has partnered with a leading elevator company to propose three innovations:
Material Innovation: Adopting 8mm one-piece molding of 304 stainless steel, CNC cutting, bending and polishing treatment, double sealing process for welding, gap ≤ 0.05 mm, particle release rate reduced from 1200 to 15 per hour.
Drive improvement: The door machine adopts magnetic levitation technology, zero contact operation, door opening and closing only 2.5 seconds, noise ≤ 45 decibels, no wear after millions of tests, particle release reduced from 800 to 5, and completely isolated vibration transmission.
System integration: EEMS with over 200 sensors is integrated with the factory system, and can switch to "ultra quiet mode" as needed. VOC filtration is activated when handling chemicals, and automatic cleaning is performed when idle.
New breakthroughs in semiconductor manufacturing
After debugging, this clean room elevator has been successfully put into use, achieving smooth, precise, and pollution-free transportation. Not only did it lay the foundation for mass production of 12 inch wafer fabs, but it also provided replicable experience for equipment procurement in the entire industry, allowing elevators to play a key role in the core process of chip manufacturing.
