Method and apparatus for cleaning surfaces with a glow discharge plasma at one atmosphere of pressure

A method for removing contaminants from a surface of a workpiece to provide a cleaned workpiece, comprising the steps of generating a steady-state, radio-frequency (RF), uniform glow discharge plasma at a pressure of from 10 torr to 20 bar, and exposing the surface with the contaminants to the generated plasma for a set period of time, thereby removing the contaminants and yielding the cleaned workpiece, wherein:

• the workpiece is an electrical conductor having a three-dimensional shape;
• and
• the method further comprises the step of generating the plasma between the workpiece, which acts as a first electrode, and a second electrode formed as a mold-image having a shape corresponding to the shape of the workpiece.

A method for removing contaminants from a surface of a workpiece to provide a cleaned workpiece, comprising the steps of generating a steady-state, radio-frequency (RF), uniform glow discharge plasma at a pressure of from 10 torr to 20 bar, between a first and a second electrode and exposing the surface with the contaminants to the generated plasma for a set period of time, thereby removing the contaminants and yielding the cleaned workpiece, wherein:

• the workpiece has a three-dimensional shape;
• and
• the method further comprises the steps of generating the plasma between the workpiece, which acts as a first electrode, and a second electrode formed as a mold-image having a shape corresponding to the shape of the workpiece and wherein said second electrode comprises an insulated metallic surface receiving a plurality of strip electrodes for connection to a plasma generating power source, and exposing the workpiece to the plasma generated by the mold-image.

An apparatus for removing contaminants from a surface of a workpiece to provide a cleaned workpiece, which comprises a first and second electrode to generate a steady-state, radio frequency (RF), uniform glow discharge plasma at a pressure of from 10 torr to 20 bar for exposing the surface with the contaminants to the generated plasma for a set period of time to remove the contaminants and yielding the cleaned workpiece;

• the workpiece is an electrical conductor having a curved shape;
• and
• the plasma is generated between the workpiece, which acts as the first electrode, and the second electrode having a curved shape corresponding to the shape of the curved workpiece.

An apparatus for removing contaminants from a surface of a workpiece to provide a cleaned workpiece, wherein:

• the apparatus is configured to generate a steady-state, radio-frequency (RF), uniform glow discharge plasma at a pressure of from 10 torr to 20 bar for exposing the surface with the contaminants to the generated plasma for a set period of time to remove the contaminants and yielding tie cleaned workpiece;
• the workpiece has a three-dimensional shape, and
• the plasma is generated between the workpiece, which acts as a first electrode, and a second electrode formed as a mold-image having a shape corresponding to the shape of the workpiece wherein said second electrode comprises an insulated surface receiving a plurality of strip electrodes for connection to a plasma generating power source, and exposing the workpiece to the plasma generated by the mold-image.

A method for removing contaminants from a surface of a workpiece to provide a cleaned workpiece, comprising the steps of generating a steady-state, radio-frequency (RF), uniform glow discharge plasma at a pressure of about one atmosphere between electrodes using an RF power source operating at a frequency of from about 100 Hz to about 30 kHz, and exposing the surface with the contaminants to the generated plasma, thereby removing the contaminants and yielding the cleaned workpiece and wherein said plasma produces ions and electrons, the RF power source operating with the electrodes to produce an electric field which traps said ions in the electric field without trapping said electrons in the electric field, thereby causing a quasi-neutral build up of positive potential of the plasma, with the electrons free to leave the plasma and collect or recombine on the surfaces of the electrodes, wherein the method is performed until the surface of the workpiece exhibits a characteristic distilled water, advancing contact angle of less than 10 degrees, as measured by a Sessile Water Drop Test, and a water drop contact diameter improvement from about 3 mm to about at least 10 mm.