In the field of semiconductor manufacturing, the importance of cleanrooms cannot be overstated. They are like the "sterile rooms" for semiconductor production, providing a stable and clean environment for high-precision and highly complex semiconductor manufacturing processes. The following are the key elements that a semiconductor cleanroom should have.

Air is the main carrier of pollutants. Tiny dust particles, microorganisms, etc. can all cause damage to semiconductor chips. HEPA filters can effectively remove particles larger than 0.3 micrometers, while ULPA filters are even more refined and can intercept particles as small as 0.12 micrometers or even smaller, ensuring that the air entering the cleanroom reaches an extremely high level of cleanliness, such as ISO 1 - ISO 4 levels.

Reasonable air circulation and airflow organization methods are crucial for maintaining cleanliness. Generally, a unidirectional flow (laminar flow) or non-unidirectional flow (turbulent flow) design is adopted. In a unidirectional flow system, air flows in parallel streamlines at a uniform speed, which can quickly carry away pollutants; non-unidirectional flow reduces the concentration of pollutants through dilution. Meanwhile, the positions of air supply outlets and return outlets also need to be considered to avoid dead air zones and ensure the even distribution of air within the cleanroom.

The semiconductor manufacturing process is extremely sensitive to temperature changes. For example, in the lithography process, a slight fluctuation in temperature may change the properties of the photoresist and affect the line width accuracy of the chip. Therefore, the cleanroom needs to maintain a stable temperature, usually controlled within the range of 22 °C ± 1 °C or an even narrower range, and uniform temperature distribution should be achieved in all areas of the cleanroom.

Humidity is equally important. Excessively high humidity may lead to water vapor condensation, causing the chip surface to get damp and corroded; too low humidity easily generates static electricity and damages the chip. Generally, the humidity is controlled between 40% and 60% through precise air-conditioning systems and humidity adjustment equipment.

From the floor, walls to the surfaces of equipment, anti-static materials should be used. For example, anti-static floors can safely conduct static charges away and prevent static accumulation. Anti-static workbenches and tools can also effectively avoid chip damage caused by static electricity during operation.

Ion fans, ion bars and other static electricity elimination equipment are widely used in the cleanroom. They generate positive and negative ions to neutralize static charges in the air and reduce the impact of static electricity on semiconductor products. Meanwhile, personnel entering the cleanroom need to wear anti-static work clothes, shoe covers, etc., and pass through static electricity elimination channels to further reduce the risk of static electricity.

The building structure of the cleanroom must have good sealing performance to prevent untreated air from the outside from entering. The connections between walls, ceilings and floors should be tight, and openings such as doors and windows should also adopt sealing designs and use sealing materials, such as rubber sealing strips, to maintain a positive pressure environment inside the cleanroom and ensure that air can only flow from the clean area to the non-clean area.

The materials for the walls, floors and ceilings of the cleanroom should not only meet the requirements of anti-static properties but also be easy to clean and corrosion-resistant. For example, the walls can be made of color steel plates, which have a smooth surface and are not easy to accumulate dust; the floor can use epoxy self-leveling materials, which have good wear resistance and cleanliness performance.

Personnel are one of the important sources of contamination in the cleanroom. Before entering the cleanroom, personnel need to go through a series of purification procedures, including changing work clothes, washing hands and disinfecting, and air showering. The air shower room removes dust, hair and other pollutants on personnel through high-speed clean air blowing.

Materials also need to be cleaned and purified before entering the cleanroom. For some large pieces of equipment, they can be cleaned and packaged outside the cleanroom and then enter the cleanroom through special transfer windows or material airlocks. The transfer windows can disinfect and purify the surface of materials during the transfer process to ensure that no pollutants are brought into the cleanroom.

In conclusion, each element of the semiconductor cleanroom is interrelated and complementary, jointly forming the key environment to ensure the quality of semiconductor manufacturing. Only by strictly controlling these elements can it be ensured that semiconductor chips are not contaminated during the production process and high-quality, high-performance products can be produced to meet the growing demands of modern technology for semiconductor chips.