Performance of Filter-Type Laminar Air Curtains When the FOUP Door Opened

Studies have shown that when the door of a Front Opening Unified Pod (FOUP) opens, the moisture or airborne molecular contamination (AMC) in the microenvironment can be influenced by the equipment layout, forming a skewed flow field. This skewed flow field can allow contaminants to enter the FOUP, adversely affecting the yield of the semiconductor manufacturing process. To effectively eliminate contaminants inside the FOUP, in addition to the common method of purging the FOUP, a laminar air curtain (LAC) device can be added to the FOUP door. This device introduces compressed dry air (CDA) at the interface between the microenvironment and the FOUP, forming flow barrier. This method effectively controls the cleanliness and humidity inside the FOUP. Currently, with the use of the laminar air curtain device, the humidity inside the FOUP significantly decreases. However, when the air reaches the bottom of the wafer box, it tends to diffuse outward, allowing contaminants to invade. To enhance the barrier effect of the air curtain, increasing the flow rate of the injected air is considered, but this can cause deformation of the perforated plate. Since the laminar air curtain device is installed near the door of the Load-Port Unit (LPU), the deformed perforated plate might collide with the LPU door, causing structural damage, generating particles, or displacing the laminar air curtain device, thus compromising its ability to effectively block contaminants from entering the FOUP. The previously developed filter-type laminar air curtain device has met the high flow rate (700 L/min) requirements and improved issues related to deformation and particle generation caused by high flow rates. However, comparative testing of performance across multiple samples in mass production is lacking. Therefore, this study will optimize the configuration of the filter-type laminar air curtain device, including the use of a perforated plate at the outlet and an airflow diffusion device inside the structure. After mass production, we will conduct performance comparisons, including indicators such as airflow uniformity and particle concentration. We expect that advancements in this research and technology will promote broader application of the filter-type air curtain device in the semiconductor industry.