Patent ID: 7354500

Claim:
A specimen preparation apparatus for ion milling away an edge of the specimen with an ion beam, comprising: a support for holding the specimen; an ion gun for directing the ion beam at the specimen held by the support; a mask for being placed in contact with a surface of the specimen, wherein the mask is a flat plate that covers the specimen except the edge thereof; means for placing the mask in contact with the surface of the specimen between the ion gun and the support so that the ion beam irradiates only the edge of the specimen and the edge of the mask; and the edge of said mask interrupting said beam determining a boundary between irradiated and unirradiated portions of the specimen, the edge of said mask being thicker than other portions of the mask and defining a plane intersecting the specimen surface, such that the edge of the mask irradiated with the ion beam is etched together with the specimen.