# US 4,399,014 A · Plasma reactor and method therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,399,014 A - Document ID: US4399014A - Status: Granted - Kind: A - Application number: 06/291,917 - Filed: 1981-08-11 - Granted: 1983-08-16 - Earliest claimed: 1980-05-03 - Inventors: Frank W. Engle - Web page: https://patentgrep.com/patent/US4399014A ## CPC - H01J 37/32532: {Electrodes} - H01J 37/3244: {Gas supply means} - H01J 37/32577: {Electrical connecting means} - H01J 37/32623: {Mechanical discharge control means} - H05K 3/0055: {After-treatment, e.g. cleaning or desmearing of holes} - H01J 2237/3355: Holes or apertures, i.e. inprinted circuit boards - H05K 2203/095: Plasma, e.g. for treating a substrate to improve adhesion with a conductor or for cleaning holes - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract A plasma reactor includes a plurality of series of parallel disposed cylindrical electrodes carried in a common vacuum vessel chamber. The series of electrodes are adapted to provide alternate polarities on each side of a plurality of workpieces, such as printed circuit boards, enclosed in the reactor for treatment. Supporting brackets are provided for positioning the workpieces, parallel to and between planes formed by series of electrodes of alternate polarities. The supporting brackets are electrically isolated from the electrodes. ## Claims ### Claim 1 A plasma reactor suitable for conditioning workpieces in a gas discharge plasma, comprising: a vacuum vessel having a chamber therein; at least one series of electrodes sin said vacuum vessel chamber, said series of electrodes being disposed along one side of a workpiece and having electrodes of alternate polarities; and means for supporting at least one workpiece to be conditioned in said plasma reactor alongside said series of electrodes. ### Claim 2 (depends on 1) The plasma reactor according to claim 1 wherein said electrodes are cylindrical in configuration. ### Claim 3 (depends on 2) The plasma reactor according to claim 2 wherein said electrodes of one polarity have a diameter differing from said electrodes of the other polarity. ### Claim 4 (depends on 1) The plasma reactor according to claim 1 wherein said chamber has a transversely curved surface, said workpiece and said series of electrodes being longitudinally disposed therein and parallel to each other. ### Claim 5 (depends on 1) The plasma reactor according to claim 1 wherein at least two said series of electrodes are provided, one on each side of said workpiece. ### Claim 6 (depends on 5) The plasma reactor according to claim 5 wherein one of said series is disposed closer to a transverse end of said vacuum vessel and comprises electrodes shorter than electrodes of another series disposed further from said end. ### Claim 7 (depends on 1) The plasma reactor according to claim 1 wherein said alternate polarities are ground potential and a predetermined RF potential. ### Claim 8 (depends on 1) The plasma reactor according to claim 1 further comprising cage frame means supported in said vacuum vessel and electrically insulated therefrom, said cage frame means carrying said series of electrodes and said means for supporting at least one workpiece. ### Claim 9 (depends on 8) The plasma reactor according to claim 8 wherein said cage frame means includes separate ground and RF buses for said series of electrodes, successive electrodes of said series being connected to alternate ones of said buses. ### Claim 10 (depends on 8) The plasma reactor according to claim 8 further comprising means for electrically isolating said electrodes from said cage frame means. ### Claim 11 (depends on 1) The plasma reactor according to claim 1 wherein said workpiece supporting means for supporting said workpiece comprises a slotted bracket having a support member carried therein and extending through a slot of said bracket, and means engaging and extending from said support member for holding a workpiece alongside said series of electrodes. ### Claim 12 (depends on 11) The plasma reactor according to claim 11 wherein said support member is a T-rail. ### Claim 13 (depends on 11) The plasma reactor according to claim 11 further comprising cage frame means supported in said vacuum vessel and electrically insulated therefrom, said slotted bracket fixed to said cage frame. ### Claim 14 (depends on 1) The plasma reactor according to claim 1 further comprising means for directing a uniform flow of gas across the workpiece when the workpiece is being conditioned in a gas discharge plasma. ### Claim 15 (depends on 14) The plasma reactor according to claim 14 wherein: (a) said vacuum vessel includes a door defining a parabolic surface in said chamber; and (b) said means for directing a uniform gas flow comprises: (i) vertically disposed baffle plates positioned within said chamber, and (ii) a plurality of radial gas inlets disposed equidistantly about said chamber, said radial gas inlets having discharge ends directed at the parabolic surface of said door and located between said baffle plates and said parabolic surface. ### Claim 16 (depends on 15) The plasma reactor according to claim 15 having at least three radial gas inlets. ### Claim 17 (depends on 15) The plasma reactor according to claim 15 wherein said vacuum vessel door is parabolically shaped. ### Claim 18 A plasma reactor system suitable for conditioning workpieces in a gas discharge plasma, comprising: (a) a vacuum vessel having a chamber therein; (b) a plurality of series of parallel disposed electrodes supported in said vacuum vessel chamber, said series having electrodes of alternate polarities; (c) means for supporting workpieces to be conditioned in said plasma reactor between adjacent series of said electrodes; (d) a vacuum pump means in communication with said vacuum vessel chamber for evacuating said chamber; (e) a gas source means in communication with said vacuum vessel chamber; and (f) an RF generator means in electrical contact with alternately positioned electrodes in each of said series. ### Claim 19 In the method of conditioning workpieces in a gas discharge plasma utilizing a plasma reactor having a vacuum vessel with a chamber therein and at least one series of electrodes supported in said chamber, the improvement comprising the steps of: disposing a workpiece alongside said series of electrodes and electrically isolated therefrom; causing said electrodes in said series to have alternate polarities; and generating a gas discharge plasma in said chamber. ### Claim 20 (depends on 19) The method of claim 19 further comprising the step of providing at least one other series of electrodes of alternate polarities adjacent the other side of said workpiece.