Wuxi Clean Room System Engineering Co.,Ltd
Add:4/4 Ruiyun, Xishan Branch Park,No.99 Furong 3rd Rd, Xishan Distric, Wuxi, Jiangsu, China
The clean room needs to control the humidity of the workshop within a reasonable range in order to ensure the product's pass rate and performance. How clean is the humidity in the cleanroom? Let's take a look with Xiao Bian. One net thinks that the choice of humidity in dust-free workshops requires specific analysis of specific conditions.
The temperature and humidity of the cleanroom are mainly determined according to the process requirements, but the human comfort level should be taken into account when meeting the process requirements. With the improvement of the air cleanliness requirements, there has been an increasingly strict demand for the temperature and humidity of the process. The specific process requirements for temperature will be listed later, but as a general principle, due to the increasingly finer processing accuracy, the requirements for the temperature fluctuation range are getting smaller and smaller.
For example, in the lithography exposure process of large-scale integrated circuit production, the difference in thermal expansion coefficient between the glass and the silicon wafer as a mask material is required to be smaller and smaller. 100 um diameter silicon wafer, the temperature rise of 1 degree, it caused a linear expansion of 0.24um, it must have a constant temperature of ± 0.1 degrees, while the required humidity value is generally lower, because people sweat, the product will be polluted, in particular Is afraid of sodium semiconductor workshop, this workshop temperature should not exceed 25 degrees, the problem of excessive humidity generated more problems. When the relative humidity exceeds 55%, condensation will form on the cooling water pipe wall. If it occurs in a precision device or circuit, it will cause various accidents. Relative humidity is rusted at 50%.
In addition, when the humidity is too high, the dust adhered to the surface of the silicon wafer is chemically adsorbed on the surface by the water molecules in the air and is difficult to remove. The higher the relative humidity is, the harder it is to remove the adhesion, but when the relative humidity is lower than 30%, the particles are also easily adsorbed on the surface due to the electrostatic force, and a large number of semiconductor devices are prone to breakdown. The optimum humidity range for silicon wafer production is 35-45%.