Wafer cleaning refers to the process of using chemical or physical methods to remove contaminants and oxides from the surface of a wafer during the manufacturing of integrated circuits, in order to meet the cleanliness requirements of the wafer surface. The principle of wafer cleaning is to remove various impurities without damaging the wafer.
There are four main mechanisms for removing particles: dissolution, oxidative decomposition, electrical repulsion between particles and silicon wafer surfaces, and slight corrosion of silicon wafer surfaces.
For the removal of metal particles, SC-2 solution or HPM solution is usually used to reduce the metal content on the wafer surface. The SC-2 solution undergoes crystallization, which may increase the number of particles on the wafer surface after cleaning. Therefore, HF can be used instead of HCL, or O3 combined with HF can be used instead of SC-2 solution to effectively remove metal particles.
For organic pollutants, SPM solution or UV/ozone dry cleaning technology is usually used for removal.
After wet cleaning, the wafer must be thoroughly dried to ensure that there are no water marks on the surface before entering the next process. The three most common drying modes currently available are rotary drying, Marangoni drying, and hot isopropanol atomization drying.
