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Knowledge of humidity control in clean room purification
Humidity control is an important condition for dust-free workshop production. Relative humidity is a common environmental control condition during the operation of dust-free workshops and clean rooms.
至 50% 的范围内，允许误差在± 1% 的狭窄的范围内，例如光刻区或者在远紫外线处理 (DUV) 区甚至更小而在其他地方则可以放松到± 5% 的范围内。 The target value of the typical relative humidity in the semiconductor clean room and clean room is controlled within the range of 30 to 50% , and the allowable error is within a narrow range of ± 1% , such as in a photolithography area or in far ultraviolet processing (DUV ) Area is even smaller and can be relaxed to within ± 5% elsewhere .
In recent years, while maintaining the air handling process within these regulations, relative humidity has a series of factors that may reduce the overall performance of clean rooms, including:
、细菌生长 ; 1.Bacteria growth ;
、工作人员感到室温舒适的范围 ; 2.The range where staff feel comfortable at room temperature ;
、出现静电荷 ; 3.Static charge appears ;
、金属腐蚀 ; 4.Metal corrosion ;
、水汽冷凝 ; 5 , water vapor condensation ;
、光刻的退化 ; 6.Degradation of photolithography ;
、吸水性。 7. Water absorption.
霉菌，病毒，真菌，螨虫 ) 在相对湿度超过 60% 的环境中可以活跃地繁殖。 Bacteria and other biological contamination ( molds, viruses, fungi, mites ) can actively reproduce in environments where the relative humidity exceeds 60% . 30% 时就可以增长。 Some flora can grow when the relative humidity exceeds 30% . 40% 至 60% 的范围之间时，可以使细菌的影响以及呼吸道感染降至最低。 When the relative humidity is in the range of 40% to 60% , the effects of bacteria and respiratory infections can be minimized.
至 60% 的范围同样也是人类感觉舒适的适度范围。 Relative humidity in the range of 40% to 60% is also a modest range for human comfort. 30% 则会让人感觉干燥，皮肤破裂，呼吸道不适以及情感上的不快。 Excessive humidity can make people feel stuffy, while humidity below 30% can make people feel dry, cracked skin, respiratory tract discomfort, and emotional discomfort.
High humidity actually reduces the build-up of electrostatic charges on the surfaces of clean rooms and clean rooms-this is the desired result. Lower humidity is more suitable for the accumulation of charge and becomes a potentially damaging source of electrostatic discharge. 时，静电荷开始迅速消散，但是当相对湿度小于 30% 时，它们可以在绝缘体或者未接地的表面上持续存在很长一段时间。 When the relative humidity exceeds 50% , the static charge begins to dissipate quickly, but when the relative humidity is less than 30% , they can persist on the insulator or ungrounded surface for a long time.
到 40% 之间可以作为一个令人满意的折中，半导体无尘车间、洁净室一般都使用额外的控制装置以限制静电荷的积累。 Relative humidity between 35% and 40% can be a satisfactory compromise. Semiconductor clean rooms and clean rooms generally use additional control devices to limit the accumulation of electrostatic charges.
The speed of many chemical reactions, including corrosion processes, will increase with increasing relative humidity. All surfaces exposed to the air surrounding the clean room and clean room are quickly covered with at least a single molecular layer of water. When these surfaces consist of a thin metal coating that can react with water, high humidity can accelerate the reaction. 但另一种情况是，例如氧化铜，是不具有保护能力的，因此，在高湿度的环境中，铜制表面更容易受到腐蚀。 Fortunately, some metals, such as aluminum, can form a protective oxide with water and prevent further oxidation reactions ; but another case, such as copper oxide, is not protective, so in In high humidity environments, copper surfaces are more susceptible to corrosion.
In environments with high relative humidity, capillary forces in the form of concentrated water form a bond between the particles and the surface, which can increase the adhesion of the particles to the siliceous surface. 时并不重要，但当相对湿度在 70% 左右时，就成为颗粒之间黏附的主要力量。 When the relative humidity is less than 50% , it is not important, but when the relative humidity is about 70% , it becomes the main force for adhesion between particles.
So far, the most urgent need for proper control in semiconductor clean rooms and clean rooms is the sensitivity of photoresist. Because the photoresist is extremely sensitive to relative humidity, its requirements for the control range of relative humidity are the most stringent.
In fact, relative humidity and temperature are critical to photoresist stability and precise dimensional control. Even at constant temperature, the viscosity of the photoresist will decrease rapidly with increasing relative humidity. Of course, changing the viscosity changes the thickness of the protective film formed by the fixed component coating. 的变异将使保护厚度改变 59.2A 。 A 3% variation in relative humidity will change the protective thickness by 59.2A .
Related links: Dongguan air-conditioning purification project, Dongguan dust-free purification equipment, Changan central air-conditioning project, low-voltage power distribution project, Dongguan purification ventilation project, Dongguan dust-free purification project, hydropower installation project, Dongguan 100,000-level dust-free workshop, Dongguan City Power Xiang Air Conditioning Purification Engineering Co., Ltd.
Article source: http://jimesale.com Tan Yuming 13751461639