One of the largest challenges faced in the semiconductor manufacturing industry is the surface contamination of silicon wafers. Most commonly, silicon wafers become contaminated simply from exposure to the air, which contains a high degree of organic particle contaminants. Once these contaminants get into the wafer, they aren’t easy to remove due to the fragile nature of the wafer. That’s why there is a specific way in which manufacturers clean the wafers. Let’s take a look at the process behind the cleaning of a Si wafer.
Solvents are used to successfully remove oils and organic residues from the surface of silicon wafers. While the solvent removes the contaminants, they also leave their own residue on the surface of the wafer. Because of that, a two-solvent method is used to ensure that the wafer is as clean as possible.
Any residue that is leftover from the solvent is taken care of with an RCA clean. The RCA clean oxidizes the silicon, thus providing a thin protective layer of oxide to the surface of the wafer.
The final step is a hydrofluoric acid dip. An HF dip is used to remove silicon dioxide from the silicon wafer surface. HF is a highly dangerous chemical, so it’s important that this step be done while wearing protective gear such as heavy gloves and eyewear.
At Wafer World, we take all the steps necessary to ensure the wafers you get are of the highest quality. Contact us today to learn more.