Ion implantation is a process used to dope ions into a work piece or target substrate. For example, ion implantation may be used to implant III-group or V-group impurity ions during the manufacture of semiconductor substrates to obtain desired electrical device characteristics. An ion implanter generally includes an ion source chamber which generates ions of a particular species, a series of beam line components configured to shape, analyze, and drive an ion beam extracted from the source chamber, and a platen for holding the target substrate (e.g., a wafer) into which the ion beam is steered. These components are housed in a vacuum environment to prevent dispersion of the ion beam during its travel from the source to the target.
The beam line components of an ion implanter may include a physical mask, often referred to as a “proximity mask,” that is suspended in the path of an ion beam for blocking a portion of the beam and thereby projecting a desired implantation pattern on a substrate. A problem commonly associated with such masks it that, when exposed to an ion beam projected thereon and therethrough, portions of the mask may heat up and expand, causing the mask to deform. Such deformation can result in the distortion of a desired implantation pattern, which may render an implanted substrate ineffective or inoperable for its intended purpose.