Plasma ashing apparatus

Claim 2

A plasma ashing apparatus having: a vacuum treatment chamber for receiving therein a substrate coated with a resist film; said vacuum treatment chamber having connected thereto a reactive gas introduction pipe equipped with a plasma applicator, and a vacuum exhaust pipe; said vacuum treatment chamber having therein heating means for heating said substrate, and two pieces of electrodes disposed in parallel to each other, one of said electrodes being a substrate electrode and the other thereof being a counter electrode; said substrate being disposed in said vacuum treatment chamber such that it is movable between a position in which it contacts a front surface of said substrate electrode and a position in which it is lifted off said surface, whereby the resist film on said substrate is removed by etching by ions and by ashing by radicals in a reactive gas to be introduced from said introduction pipe; wherein said substrate electrode and said counter electrode are commonly connected to an RF power source to thereby constitute a cathode electrode; and wherein multiple concentric circumferentially extending apertures are formed in said counter electrode with radially extending electrode rib portions intersecting said apertures.

Claim 3

A plasma ashing apparatus according to claim 1, wherein said counter electrode has a disk shape; a central perforation is formed in a center of said counter electrode; and said concentric circumferentially extending apertures are formed at distances from said center which are multiples of a diameter of said central perforation thus defining circular electrode surfaces between said apertures corresponding in width to a radius of said central perforation.

Claim 4

A plasma ashing apparatus according to claim 2, wherein a dummy electrode of ground electric potential is provided in said central perforation.

Claim 5

A plasma ashing apparatus according to claim 2, wherein a circular peripheral wall portion which projects towards said substrate electrode is formed in a periphery of said counter electrode.

Claim 6

A plasma ashing apparatus according to claim 4, wherein a surface of said counter electrode is coated with aluminum oxide.

Claim 7

A plasma ashing apparatus according to claim 1, wherein said cathode electrode connected to said RF power source discharges between said cathode electrode and an appropriate anode which includes a chamber wall of said vacuum treatment chamber.

Claim 8

A plasma ashing apparatus having: a vacuum treatment chamber for receiving therein a substrate coated with a resist film; said vacuum treatment chamber having connected thereto a reactive gas introduction pipe equipped with a plasma applicator, and a vacuum exhaust pipe; said vacuum treatment chamber having therein heating means for heating said substrate, and two pieces of electrodes disposed in parallel to each other, one of said electrodes being a substrate electrode and the other thereof being a counter electrode; said substrate being disposed in said vacuum treatment chamber such that it is movable between a position in which it contacts a front surface of said substrate electrode and a position in which it is lifted off said surface, whereby the resist film on said substrate is removed by etching by ions and by ashing by radicals in a reactive gas to be introduced from said introduction pipe; wherein said substrate electrode and said counter electrode are commonly connected to an RF power source to thereby constitute a cathode electrode; and multiple concentric perforations are formed in said counter electrode except for a rib portion; wherein said counter electrode has a disk shape, a central perforation being formed in a center of said counter electrode, and the concentric perforations being formed at distances from the center which are multiples of a diameter of the central perforation thus defining circular electrode surfaces corresponding in width to a radius of the central perforation; and wherein a dummy electrode of ground electric potential is provided in the central perforation.

Claim 9

A plasma ashing apparatus having: a vacuum treatment chamber for receiving therein a substrate coated with a resist film; said vacuum treatment chamber having connected thereto a reactive gas introduction pipe equipped with a plasma applicator, and a vacuum exhaust pipe; said vacuum treatment chamber having therein heating means for heating said substrate, and two pieces of electrodes disposed in parallel to each other, one of said electrodes being a substrate electrode and the other thereof being a counter electrode; said substrate being disposed in said vacuum treatment chamber such that it is movable between a position in which it contacts a front surface of said substrate electrode and a position in which it is lifted off said surface, whereby the resist film on said substrate is removed by etching by ions and by ashing by radicals in a reactive gas to be introduced from said introduction pipe; wherein said substrate electrode and said counter electrode are commonly connected to an RF power source to thereby constitute a cathode electrode; and multiple concentric perforations are formed in said counter electrode except for a rib portion; wherein said counter electrode has a disk shape, a central perforation being formed in a center of said counter electrode, and the concentric perforations being formed at distances from the center which are multiples of a diameter of the central perforation thus defining circular electrode surfaces corresponding in width to a radius of the central perforation; and wherein a dummy electrode of ground electric potential is provided in the central perforation.