US Patent 6927358 Vacuum seal protection in a dielectric break

In one aspect of the invention is a method to create a vacuum seal with extended lifetime to form a dielectric break in a vacuum chamber. The method includes the use of an elastic dielectric seal to form a high vacuum seal. It also includes the use of different means to protect the vacuum seal from direct exposure to the plasma and to reactive gases present inside the plasma chamber. Furthermore, it includes the use of elements to ensure a proper compression of the elastic seal, and to avoid its expansion or contraction when the pressures on both sides of the seal are different.