Method of heating and cooling large area substrates and apparatus therefor

A vacuum system including at least one vacuum chamber selected from the group consisting of a heating chamber and a cooling chamber for glass substrates to be processed, said chamber including

• a) means to provide a vacuum to said chamber,
• b) a heating or cooling means incorporated into the interior sidewalls of a cassette in said chamber for changing the temperature of the interior sidewalls of said cassette in said chamber,
• c) a plurality of thermally conductive shelves contacting said sidewalls so that heat is conducted to and from said conductive shelves from said sidewalls,
• d) dielectric supports for said glass substrates mounted on said conductive shelves so as to provide a gap between said substrates and said shelves, thereby avoiding direct contact of the glass substrates to said shelves, to preclude direct heat transfer from said shelves to said substrates, said means of heating and cooling able to heat the glass substrates to a temperature of about 350.degree.-400.degree. C. and to cool the glass substrate to ambient temperatures from a temperature of about 300.degree.-400.degree. C. at a rate so as to avoid thermal stress in said glass substrates.