Some dry pumps are equipped with an oil box or grease along with the bearings in a vacuum and are not necessarily oil-free. This article introduces a completely oil-free scroll pump. There are also scroll pumps that have bearings in the vacuum space and pumps that have bearings only in the atmospheric pressure space. Scroll pumps with bearings only in the atmospheric pressure space are completely oil-free dry pumps, with no back-diffusion of oil into the vacuum chamber. It also has excellent water vapor processing capacity and ease of maintenance by end users.