US 5,688,358 AGranted

R.F. plasma reactor with larger-than-wafer pedestal conductor

AssigneeApplied Materials, Inc.

InventorsYoichiro Tanaka, Megumi Taoka, Barney Cohen

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Abstract

A pedestal for supporting a semiconductor substrate in an R.F. plasma reactor chamber includes a conductive disk platen having a diameter exceeding the diameter of the substrate so that an outer annular portion of the conductive disk platen provides a direct path of R.F. power from the plasma while a remaining inner portion of the conductive disk provides a path of R.F. power from the plasma through the substrate, an etch-resistant cover shielding the conductive platen from the plasma, a portion of the etch-resistant layer underlying the substrate, the etch-resistant cover including a raised disk overlying a central portion of the conductive disk platen and underlying the substrate and having a diameter less than the diameter of the substrate so that a peripheral portion of the substrate extends beyond the circumference of the raised disk, a recessed ring annulus overlying an outer portion of the conductive disk platen and having a top surface which is depressed below a top surface of the raised disk, an inner portion of the recessed ring annulus underlying the peripheral portion of the substrate, leaving a top portion of a side wall of the raised disk exposed to the plasma.

Claims15

Dependent claims

A plasma reactor comprising:

a reactor chamber;
a gas source for supplying a process gas into the interior of said chamber;
a power applicator for coupling power into the interior of said chamber so as to create a plasma of said process gas;
a pedestal inside said chamber with a semiconductor substrate located thereon, said pedestal electrically connected to provide a return path for said power, said pedestal comprising:
a conductive disk platen for supporting said semiconductor substrate having a substrate diameter to be processed as a workpiece in said reactor, said platen having a diameter exceeding the diameter of said substrate so that an outer annular portion of said conductive disk platen provides a direct path for said power from said plasma while a remaining inner portion of said conductive disk provides a path for said power through said semiconductor substrate;
an etch-resistant cover shielding said conductive platen from said plasma, a portion of said etch-resistant cover underlying said substrate, said etch-resistant cover comprising:
an etch-resistant raised disk overlying a central portion of said conductive disk platen and underlying said substrate and having a diameter less than the diameter of said beyond the circumference of said raised disk,
an etch-resistant recessed ring annulus overlying an outer portion of said conductive disk platen and having a top surface which is depressed below a top surface of said raised disk, an inner portion of said recessed ring annulus underlying said peripheral portion of said substrate, leaving a top portion of a side wall of said raised disk exposed to said plasma.

5 more elements

A pedestal in the interior of a plasma reactor vacuum chamber containing a plasma formed from a processing gas by applied R.F. power, said pedestal comprising:

a conductive disk platen with a semiconductor substrate located thereon and having a substrate diameter to be processed as a workpiece in said reactor, said platen having a diameter exceeding the diameter of said substrate so that an outer annular portion of said conductive disk platen provides a direct path of R.F. power from said plasma while a remaining inner portion of said conductive disk provides a path of R.F. power from said plasma through said substrate;
an etch-resistant cover shielding said conductive platen from said plasma, a portion of said etch-resistant cover underlying said substrate, said etch-resistant cover comprising:
an etch-resistant raised disk overlying a central portion of said conductive disk platen and underlying said substrate and having a diameter less than the diameter of said substrate so that a peripheral portion of said substrate extends beyond the circumference of said raised disk,
an etch-resistant recessed ring annulus overlying an outer portion of said conductive disk platen and having a top surface which is depressed below a top surface of said raised disk, an inner portion of said recessed ring annulus underlying said peripheral portion of said substrate, leaving a top portion of a side wall of said raised disk exposed to said plasma.

1 more element

Dependencies are inferred from the claim text.