The present invention provides a thin film spacer for maintaining a gap between a slit valve door and a sealing surface of a slit valve, such as a metallic insert. The film spacer can extend the life of a seal by limiting the line of sight exposure of the seal to corrosive gases within a wafer processing chamber, for example, and by controlling the compression percentage of the seal. The spacer may be located on an outer ambient side of the slit valve away from any corrosive gasses that may exist in the chamber.