Plasma etching apparatus with dielectrically isolated electrodes

Claim 1

A dry etching apparatus, comprising: a vacuum chamber; means for introducing a reactive gas into said vacuum chamber; a first electrode provided within said vacuum chamber; a second electrode provided within said vacuum chamber in substantially spatial parallel relationship with said first electrode; at least one to be processed substrate being superposed over said first electrode; means for applying electrical power to said first electrode for generating a plasma from said reactive gas in a space in said vacuum chamber between said first and second electrodes to etch said substrate, said plasma inducing a negative self-bias voltage in said substrate; means including at least one substrate support and dielectric members, there being gaps between said substrate support and dielectric members, and between individual dielectric members, said substrate support and dielectric members being provided for completely covering a surface of said first electrode opposed to said second electrode; wherein said substrate support includes: a dielectric portion having a surface for accepting said substrate; and a conductive portion provided below said dielectric portion having the same electrical potential as said first electrode; wherein at least one gap extension is defined by said substrate support and dielectric members and extends along at least one of the gaps between said dielectric members and along at least one of the gaps between one of said dielectric members and said substrate support, said gap extension zigzagging from said surface of said first electrode to said plasma space such that, irrespective of the dimensions of said substrate, said plasma space cannot be viewed from said surface of said first electrode; and means for applying a negative biasing voltage having a larger absolute value than said negative self-bias voltage in said substrate to said first electrode; whereby said substrate is electrostatically attracted tightly to said substrate support to promote efficient heat transfer between said substrate and said first electrode.