Patent ID: 6712929
Filing Date: 2004-03-30
Classification: H01J,H01L

Abstract:
An apparatus, comprising:a vacuum chamber wall defining a main cavity and an opening; an exhaust port in fluid connection with the main cavity for establishing a vacuum in the main cavity; a cover for sealing the opening when the cover is supported by the chamber wall, comprising: a first section adjacent to the main cavity, wherein the first section of the cover is supported by the chamber wall; a second section on a side of the first section opposite of the main cavity, wherein the second section is supported by the first section; a pocket between the first section and the second section; a vacuum tight seal between the first section and the second section; and a vacuum tight seal between the first section and the vacuum chamber wall; and a critical element supported by a region of the first section and extending into the main cavity from the first section, wherein support of the second section by the first section is not above support of the critical element by the first section, wherein the pocket extends between the first section and the second section above the region of the first section upon which the critical element is supported, so that the first section separates the critical element and the pocket.