What is a laboratory cleaning system?

2023-10-28 10:43
4

The main function of a clean room is to control the cleanliness, temperature, and humidity of the atmosphere in which products (such as silicon chips) come into contact, so that products can be produced and manufactured in a good environmental space, which we call a clean room. According to international practice, the level of dust-free purification is mainly determined by the number of particles per cubic meter of air with a diameter greater than the classification standard. That is to say, the so-called dust-free is not 100% without any dust, but controlled in a very small unit. Of course, the particles that meet the dust standard in this standard are already very small compared to our common dust, but for optical structures, even a small amount of dust can have a significant negative impact. Therefore, in the production of optical structure products, dust-free is an inevitable requirement.


By controlling the number of fine dust particles with a particle size of less than 0.3 micrometers per cubic meter to below 3500, it meets the A-level international dust free standard. At present, the dust-free standards applied in chip level production and processing have higher requirements for dust than Class A, and such high standards are mainly applied in some higher-level chip production. The amount of fine dust is strictly controlled within 1000 per cubic meter, which is commonly known as the 1K level in the industry.


微信圖片_20190725135804.jpg



There are three main uses of clean rooms:


1. Air clean room: A clean room (facility) that has been built and can be put into use. It has all relevant services and functions. However, there are no equipment operated by operators within the facility.


2. Static clean room: A clean room (facility) with complete functions and proper installation, which can be used or in use according to the settings, but there are no operators inside the facility.


3. Dynamic clean room: A clean room in normal use, with complete service functions, equipment, and personnel; If necessary, can engage in normal work.


1、 Clean room control project: (1) capable of removing fine dust particles floating in the air; (2) Can prevent the generation of fine dust particles; (3) Control of temperature and humidity; (4) Pressure regulation; (5) Removal of harmful gases; (6) The airtightness of structures and compartments; (7) Prevention of static electricity; (8) Electromagnetic interference prevention; (9) Safety considerations; (10) Energy saving considerations.


2、 The importance of clean room airflow


The cleanliness of a clean room is often influenced by airflow, in other words, the movement and diffusion of dust generated by people, machine compartments, building structures, etc. are controlled by airflow. The clean room uses HEPA and ULPA to filter air, with a dust collection rate of 99.97-99.9995%. Therefore, the air filtered by this filter can be said to be very clean. However, in addition to humans, there are also dust sources such as machines in the clean room. Once these generated dust spreads, it is impossible to maintain a clean space. Therefore, it is necessary to use airflow to quickly exhaust the generated dust from the outside.


微信圖片_20190725135719.jpg



3、 Control of wind speed in clean rooms


The airflow in a clean room is an important factor affecting the performance of the left and right clean rooms. Generally, the airflow speed in a clean room is between 0.25 and 0.5m/s. This airflow speed belongs to a breezy area and is easily disturbed and tends to become chaotic by actions of people, machines, etc. Although increasing the wind speed can suppress the impact of this disturbance and maintain cleanliness, the increase in wind speed will affect the increase in operating costs. Therefore, when meeting the required cleanliness level, Able to supply at an appropriate wind speed to achieve economic results. On the other hand, in order to achieve a stable effect of clean room cleanliness, maintaining uniform airflow is also an important factor. If uniform airflow cannot be maintained, it indicates that there is a difference in wind speed, especially on the wall. The airflow will cause eddy currents along the wall, making it difficult to achieve high cleanliness.


4、 The influencing factors of clean rooms


There are many factors that affect the airflow in a clean room, such as process equipment, personnel, clean room assembly materials, lighting fixtures, etc. At the same time, the diversion points of airflow above production equipment should also be considered. The airflow diversion points on the surface of general operating platforms or production equipment should be located at a distance of 2/3 between the clean room space and the partition board, so that when operators work, the airflow can flow from the inside of the process area to the work area and carry away the fine dust; If the diversion point is located in front of the process area, it will become an improper airflow diversion. At this time, most of the airflow will flow to the process area, and the dust caused by the operator's operation will be carried to the back of the equipment, resulting in contamination of the workbench and a decrease in yield.


Obstacles such as work desks in the clean room will experience eddy currents at their junctions, resulting in poor cleanliness near them. Drilling return air holes on the work desk will minimize eddy currents; The selection of assembly materials and the completeness of equipment layout are also important factors in determining whether airflow becomes a vortex phenomenon.