Electric heating – Metal heating – By arc
Reexamination Certificate
1999-08-31
2001-03-06
Paschall, Mark (Department: 3742)
Electric heating
Metal heating
By arc
C219S121520, C219S121410, C204S298380, C204S192320, C156S345420
Reexamination Certificate
active
06198067
ABSTRACT:
BACKGROUND OF THE INVENTION
(i) Field of the Invention
The present invention relates to a device for processing circuit supports with plasma excited by a microwave, particularly to a device capable of performing plasma processing for, e.g., surface-refining or etching to both surfaces of a large number of circuit supports such as flexible circuit boards at a time.
(ii) Description of the Related Art
Plasma processing devices of microwave excitation type are used in many fields.
FIG. 6
shows an example of such a device, in which a waveguide
51
is disposed at an insulator window hermetically attached to an upper portion of a quartz chamber
50
. A magnetron
52
is disposed at the top of the waveguide
51
. An object
54
to be processed is placed on an insulator table
53
in the quartz chamber
50
. Reaction gas
55
is introduced into the quartz chamber
50
through one portion thereof while the chamber is exhausted with a vacuum pump through a vacuum exhaust port
57
. The vacuum pressure in the quartz chamber
50
is checked with a pressure gauge
56
, and then the magnetron
52
is energized to perform aimed plasma processing to the object
54
. Plasma processing devices of this type are widely used for, e.g., etching or CVD processes for semiconductor wafers.
FIG. 7
shows another example, in which the interior of a metal chamber
60
is hermetically divided with an insulator window
62
, and a magnetron
61
is disposed at the top of the chamber above the window. An object
64
to be processed is placed on an insulator table
63
in the metal chamber
60
. Reaction gas
65
is introduced into the metal chamber
60
through one portion thereof while the chamber is exhausted with a vacuum pump through a vacuum exhaust port
67
. The vacuum pressure in the metal chamber
60
is checked with a pressure gauge
66
, and then the magnetron
61
is energized to perform aimed plasma processing to the object
64
. Plasma processing devices of this type are widely used for etching processes for semiconductors, TFTs, printed-circuit boards, etc., or in other various fields for, e.g., ashing photoresist, etching, or cleaning or refining surfaces.
Such plasma processing devices as described above, however, can process only one or few objects at a time in consideration of uniformity in processing over the objects. This is because the surface of each object to be processed faces the plasma source and so their locations are restricted by the space in cross section of the chamber and the plasma distribution therein.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a device capable of performing plasma processing for, e.g., surface refining or etching to both surfaces of a large number of circuit supports such as flexible circuit boards or both surfaces of a continuous sheet of flexible circuit supports at a time in considerable parts of cross section and height of a chamber without inequality or restriction by the plasma distribution and size of a plasma source.
According to the present invention, in a plasma processing device for circuit supports in which objects to be processed are processed with plasma by applying a microwave generated by a magnetron from an upper portion of a hermetically sealed metal chamber in said metal chamber, a large number of boards to be processed are disposed within said metal chamber in an isolated state, a large number of ground electrode plates are disposed near by both surfaces of said boards so as to be at the same potential as said metal chamber, and both surfaces of said boards are processed at a time with plasma by using glow discharges produced between said boards and said ground electrode plates due to a difference in high-frequency potential between said boards and said ground electrode plates under presence of reaction gas.
It is preferable that each of said ground electrode plates is larger than each of said boards to be processed. It is suitable that each of said ground electrode plates is mesh-like or porous. Said boards to be processed can be supported through their lower end portions by a holder at predetermined intervals.
For increasing the number of boards processed at a time, it is advantageous that holders are disposed in layers within said metal chamber in an isolated state, a large number of boards to be processed are disposed on each of said holders at predetermined intervals, and a large number of ground electrode plates are disposed near by both surfaces of said boards so as to be at the same potential as said metal chamber.
The present invention can provide not only such a device as described above for rectangular boards but also a device by which both surfaces of a continuous sheet comprising a large number of divisions of flexible circuit supports can be continuously processed with plasma at a time.
In this case, a plasma processing device for circuit supports in which objects to be processed are processed with plasma by applying a microwave generated by a magnetron from an upper portion of a hermetically sealed metal chamber in said metal chamber, is basically constructed as follows: a continuous sheet of circuit supports to be processed is moved in a zigzag path through a large number of intermediate rolls vertically, a large number of ground electrode plates are disposed near by and along both sides of said path so as to be at the same potential as said metal chamber, and both surfaces of said sheet are processed at a time with plasma by using glow discharges produced between said sheet and said ground electrode plates due to a difference in high-frequency potential between said sheet and said ground electrode plates under presence of reaction gas.
REFERENCES:
patent: 4633811 (1987-01-01), Maruyama
patent: 4663829 (1987-05-01), Hartman et al.
patent: 4971667 (1990-11-01), Yamazaki et al.
Ikeda Hiroyuki
Mori Ryoichi
Shiga Shoji
Alix Yale & Ristas, LLP
Nippon Mektron Ltd.
Paschall Mark
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