Plasma desmearing apparatus and method

A method of desmearing, comprising the steps of:

• providing a rectangular confinement for the flow of plasma gas excited by a radio frequency generator at very low pressure;
• positioning pairs of electrodes in close spaced relationship to provide a primary field between the electrodes of each pair, one electrode of each pair being connected to the radio frequency source and the other to ground and spacing the pairs of such electrodes a sufficient distance apart to permit the insertion of objects to be desmeared in the secondary field between the adjacent pairs;
• directing the flow of plasma through the electrodes and confined in the rectangular path to impact the objects to be desmeared;
• reversing the flow of the plasma after desmearing has taken place in one direction for a finite period of time;
• and
• the entirety of all the above steps being performed within the rectangular confinement at very low pressure.

A method of desmearing, comprising the steps of:

• providing a rectangular confinement for the flow of plasma gas excited by a radio frequency generator at very low pressure;
• positioning pairs of electrodes in close spaced relationship to provide a primary field between the electrodes of each pair, one electrode of each pair being connected to the radio frequency source and the other to ground and spacing the pairs of such electrodes a sufficient distance apart to permit the insertion of objects to be desmeared in the secondary field between the adjacent pairs;
• positioning a plurality of printed circuit boards vertically in said secondary field;
• directing the flow of plasma to flow through the electrodes and confined in the rectangular path to impact the objects to be desmeared;
• reversing the flow of the plasma after desmearing has taken place in one direction for a finite period of time, and
• the entirety of all the above steps being performed within the rectangular confinement at very low pressure.

In an apparatus for plasma desmearing comprising, in combination:

• a chamber rectangular in cross-section;
• door means for access to said chamber from one side thereof;
• a diffusion chamber on each end of said chamber;
• means connecting the ends of two diffusion chambers to a reduced pressure source;
• means for introducing at least one gas into said rectangular chamber at the ends thereof when the same is substantially evacuated by the vacuum means;
• a plurality of electrodes positioned, in close proximate relationship in pairs, transverse to the direction of the flow of the gas within said chamber, one electrode of each pair being connected to a radio frequency generating means and the other electrode of each pair being connected to ground, thereby defining a primary field between said closely spaced pairs;
• adjacent pairs of electrodes defining spaces therebetween for forming a secondary field;
• means for securing objects to be desmeared between the adjacent pairs of electrodes and in the secondary field;
• the electrodes including sufficient openings to assist in diffusing the plasma gas while passing therethrough prior to and after impacting the objects to be desmeared;
• and
• control means for providing plasma flow through the rectangular chamber while the radio frequency generator is operating.

The method of desmearing, comprising the steps of:

• providing a chamber for the confinement for the flow of plasma gas excited by a radio frequency generator at very low pressure,
• positioning pairs of apertured electrodes in close spaced relationship to provide a primary field between the electrodes of each pair, one electrode of each pair being connected to the radio frequency source and the other to ground and spacing the pairs of such electrodes a sufficient distance apart to permit the insertion of objects to be desmeared in the secondary field between the adjacent pairs,
• directing the flow of the plasma to flow transverse to the electrode through apertures in the electrodes and confined in the chamber to impact the objects to be desmeared,
• the entirety of all the above steps being performed within the chamber at very low pressure.

A method of desmearing, comprising the steps of:

• providing a chamber for the confinement for the flow of plasma gas excited by a radio frequency generator at very low pressure,
• positioning pairs of electrodes in close spaced relationship to provide a primary field between the electrodes of each pair, one electrode of each pair being connected to the radio frequency source and the other to ground and spacing the pairs of such electrodes a sufficient distance apart to permit the insertion of objects to be desmeared in the secondary field between the adjacent pairs,
• directing the flow of the plasma through the electrodes and confined in the chamber to impact the objects to be desmeared,
• reversing the flow of the plasma after desmearing has taken place in one direction for a finite period of time, and
• the entirety of all the above steps being performed within the chamber at very low pressure.

A method of desmearing, comprising the steps of:

• providing a chamber for the confinement for the flow of plasma gas excited by a radio frequency generator at very low pressure,
• positioning pairs of electrodes in close spaced relationship to provide a primary field between the electrodes of each pair, one electrode of each pair being connected to the radio frequency source and the other to ground and spacing the pairs of such electrodes a sufficient distance apart to permit the insertion of objects to be desmeared in the secondary field between the adjacent pairs,
• positioning a plurality of printed circuit boards vertically in said secondary field,
• directing the flow of the plasma through the electrodes and confined in the chamber to impact the objects to be desmeared,
• reversing the flow of the plasma after desmearing has taken place in one direction for a finite period of time, and
• the entirety of all the above steps being performed within the chamber at very low pressure.

An apparatus for plasma desmearing, comprising in combination:

• a chamber for confining the path of plasma;
• door means for access to said chamber from one side thereof;
• a diffusion chamber on each end of said chamber;
• means connecting the ends of the two diffusion chambers to a reduced pressure source;
• means for introducing at least one gas into said chamber at the ends thereof when the same is substantially evacuated by the vacuum means;
• a plurality of apertured electrodes positioned in close proximate relationship in pairs, transverse to the direction of the flow of the gas within said chamber, one electrode of each pair being connected to a radio frequency generating means and the other electrode of each pair being connected to ground, thereby defining a primary field between said closely spaced pairs;
• adjacent pairs of electrodes defining spaces therebetween for forming a secondary field;
• means for securing objects to be desmeared between the adjacent pairs of electrodes and in the secondary field;
• and control means for providing plasma flow through the chamber while the radio frequency generator is operating.