In semiconductor fabrication manufacturing, minimization of particle contamination on semiconductor wafers is getting increasingly important as the integrated circuit (IC) devices on the wafers decrease in size.
IC manufacturing generally involves deposition of a thin dielectric or conductive film on the wafer, using oxidation or any of a variety of chemical vapor deposition (CVD) processes that provide ample opportunity for organic, metal, or other circuit contamination. Because the presence of such particles affects the functional integrity of the devices in the finished electronic product, particles must be removed from the environment.
Modern semiconductor manufacturing is carried out in a cleanroom, which is isolated from the outside environment to stringently control contaminants such as airborne particles, metals, organic molecules and electrostatic discharge (ESD).
The present invention relates to the air purification systems in semiconductor manufacturing cleanrooms. In this embodiment, the invention aims to provide a purification system for removing acidic airborne molecular contamination (AMC) and alkaline AMC from a gas stream. The air purification system (A) includes a housing (B) with an acidic water supply device (C) and an alkaline water supply device (D).
The gas stream (E) enters the housing and the acidic water supply device supplies acidic water via a pump (F) to the first nozzles (G), which spray acidic mist that is capable of neutralizing alkaline AMC such as ammonia. The alkaline water supply device supplies alkaline water via a pump (H) to the second nozzles (I), which spray alkaline mist that is capable of neutralizing acidic AMC such as SO2, HCl, HF, and NO2.
The nozzles are directed toward the water droplet trap (J), where the acidic and alkaline water spray droplets accumulate and merge with each other. The droplets, containing the acidic and alkaline AMC and particles, are collected in a drain pan (not shown) at the bottom of the housing.
Patent number: 7,025,809
Date: April 11, 2006
Inventors: Yung-Dar Chen (Hsinchu, Taiwan); Po-Sung Kuo (Tainan, Taiwan); Yen-Chun Wang (Taipei, Taiwan)