The Fan Filter Unit (FFU) is instrumental in ensuring electronic cleanrooms achieve their designated classification levels. This article examines the classification system of electronic cleanrooms and how FFU layout significantly contributes to maintaining air purity and operational efficiency. Class 100 and above environments require unidirectional airflow and dense FFU deployment, while Class 1000 and 10000 can adopt less exhaustive layouts. By considering room dimensions, ceiling height, materials, and infrastructure, a tailored FFU design ensures both high performance and cost-effectiveness, ultimately enhancing the success of delicate electronic production processes.