US4902870A — Apparatus and method for transfer arc cleaning of…

Claim 1

Independent Claim 185 words

An RF plasma system for arc cleaning oxides from the surface of a substrate during RF plasma processing of the substrate comprising: an RF plasma device including a dielectric enclosure defining a chamber for containing a plasma and having a plasma exit port through which said plasma flows, an electrical conductor coil adjacent to the enclosure for applying RF energy to a region within the chamber to create a plasma from a gas flowing in the chamber and an electrically conductive member at said port and secured to said enclosure, said member being sufficiently close to said flowing plasma to permit current to flow to the plasma from the member; a substrate support for holding a substrate adjacent to said port for processing by the plasma flowing through the port; and means for providing a direct current (DC) voltage between said member and said substrate support, said voltage having a polarity and magnitude such that an electric arc flows from said member to said substrate via said plasma, said arc being of sufficient intensity to substantially remove said oxides from said substrate during said processing.

Claim 2

Dependent Claim 185 words

An RF plasma system for arc cleaning oxides from the surface of a substrate during RF plasma processing of the substrate comprising: an RF plasma device including a dielectric enclosure defining a chamber for containing a plasma and having a plasma exit port through which said plasma flows, an electrical conductor coil adjacent to the enclosure for applying RF energy to a region within the chamber to create a plasma from a gas flowing in the chamber and an electrically conductive member at said port and secured to said enclosure, said member being sufficiently close to said flowing plasma to permit current to flow to the plasma from the member; a substrate support for holding a substrate adjacent to said port for processing by the plasma flowing through the port; and means for providing a direct current (DC) voltage between said member and said substrate support, said voltage having a polarity and magnitude such that an electric arc flows from said member to said substrate via said plasma, said arc being of sufficient intensity to substantially remove said oxides from said substrate during said processing.

Claim 3

Dependent Claim 18 words

The system of claim 1 wherein said member is at a positive reference potential relative to said substrate.

Claim 4

Dependent Claim 12 words

The system of claim 1 wherein said member is at ground potential.

Claim 5

Dependent Claim 30 words

The system of claim 1 wherein said electrically conductive member is annular, said means for providing a voltage includes means for providing a negligible voltage drop across said annular member.

Claim 6

Dependent Claim 54 words

The system of claim 1 further including an electrically conductive gas confining tank defining a second chamber, said tank including means for positioning said support in the second chamber electrically isolated from the tank, said annular member being electrically conductively secured to said tank with said exit port in communication with said second chamber.

Claim 7

Dependent Claim 29 words

The system of claim 5 wherein said means for providing said voltage includes means for applying a positive potential to said tank and a negative potential to said support.

Claim 8

Dependent Claim 27 words

The system of claim 1 wherein said means for providing a voltage includes an electrically conductive plasma device support structure in electrically conductive contact with said member.

Claim 9

Dependent Claim 40 words

The system of claim 7 wherein said means for providing a voltage include means for applying a positive potential to said member so as to effectively produce a substantially uniform potential drop across said member when said arc is present.

Claim 10

Dependent Claim 178 words

An RF plasma system for arc cleaning oxides from a substrate surface during RF plasma processing of the substrate comprising: an electrically conductive housing forming a first chamber; means for positioning a substrate within the first chamber and electrically isolated from the housing; an RF plasma device comprising an RF coil surrounding a tubular dielectric member forming a second chamber, means for flowing a gas through the second chamber into the first chamber via an exit port of the second chamber, and an electrically conductive support electrically conductively secured to the housing at said exit port for supporting said coil and member so that RF energy is applied to said flowing gas in the second chamber to form a plasma which flows through said exit port; and means for placing said means for positioning at a negative DC potential relative to said housing and said support such that a DC arc flows from said electrically conductive support via said plasma to said positioned substrate, said arc being of sufficient intensity to substantially remove said oxides from said substrate.

Claim 11

Dependent Claim 178 words

An RF plasma system for arc cleaning oxides from a substrate surface during RF plasma processing of the substrate comprising: an electrically conductive housing forming a first chamber; means for positioning a substrate within the first chamber and electrically isolated from the housing; an RF plasma device comprising an RF coil surrounding a tubular dielectric member forming a second chamber, means for flowing a gas through the second chamber into the first chamber via an exit port of the second chamber, and an electrically conductive support electrically conductively secured to the housing at said exit port for supporting said coil and member so that RF energy is applied to said flowing gas in the second chamber to form a plasma which flows through said exit port; and means for placing said means for positioning at a negative DC potential relative to said housing and said support such that a DC arc flows from said electrically conductive support via said plasma to said positioned substrate, said arc being of sufficient intensity to substantially remove said oxides from said substrate.

Claim 12

Dependent Claim 16 words

The system of claim 9 including means for operating the RF device at about 250-400 KHz.

Claim 13

Dependent Claim 16 words

The system of claim 9 including means for operating the RF device at about 1-10 MHz.

Claim 14

Dependent Claim 17 words

The system of claim 9 wherein the first chamber is at a pressure below ambient atmospheric pressure.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-02-19	1993-08-21	1994-02-20	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-02-19	1997-08-21	1998-02-20	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-02-19	2001-08-21	2002-02-20	$7700.00	Window Closed / Lapsed

Apparatus and method for transfer arc cleaning of a substrate in an RF plasma system

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