Abstract:
A plasma source is designed with a starting rod to reduce target vapor shielding. A curve ion duct has reverse thorns on its inner wall to filter macroparticles in plasma. The curve ion duct has duct segments and each duct segment has an individual electricity. The present invention increases ion amount, acquires a film through high energy ions, and obtains enhanced film adhesion and film quality.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a plasma source; more particularly, relates to coating metal or ceramic film on a workpiece with enhanced quality, prolonged lifetime, improved flexibility and shortened producing time. 
       DESCRIPTION OF THE RELATED ARTS 
       [0002]    An arc plasma coating is operated in a vacuum environment, where a plasma is obtained between a node and cathode with low voltage. A target is set at the cathode to generate metal ions through a discharging to be deposited on a surface of a workpiece. In such a process, a high current passes through the surface of the target to evaporate the target owing to the heat generated under a great power. As a result, microcraters may happen on the surface of the target and macroparticles from the target are scattered around. And, when the macro particles are deposited on the surface of the workpiece, the surface becomes rugged and porous and so the quality of the film obtained is reduced. 
         [0003]    One of the best device now for filtering the macroparticles is a filtered cathodic vacuum arc (FCVA), where the target ions are biased by a magnetic field to deposit on the surface of the workpiece after passing through a curve duct. Because the macroparticles are heavier than the ions, they do not pass through the duct and so are filtered. The duct may be also equipped with a series of stopping rings to avoid macro particles from escaping out of the duct. 
         [0004]    Yet the FCVA device has only one channel and is hard to bear high heat so that it is not suitable for a high-energy ion source. Besides, the device does not output a pulse ion current. Hence, the prior arts do not fulfill users&#39; requests practically. 
       SUMMARY OF THE INVENTION 
       [0005]    The main purpose of the present invention is to enhance an ion amount and control an ion energy with combinations of modules of various biases or various magnetic fields; to improve deposition rate; to reduce impurities in a film; and to enhance a film quality. 
         [0006]    To achieve the above purpose, the present invention is a macroparticle-filtered coating plasma source device, comprising a plasma source, a curve ion duct, a controller, an arc source and a multi-channel power source, where the plasma source has a target, a trigger rod and a guiding rod; the curve ion duct is connected with the plasma source at an end; the curve ion duct comprises a plurality of duct segments each having an individual electricity; the curve ion duct obtains a pulse ion source by swiftly changing among the duct segments between a bias power source and a power source of an electromagnetic coil through a multi-channel power source; the duct segments are assembled with a 2-dimensional arrangement or a 3-dimensional arrangement; and the curve ion duct is cooled down with a cooling water, has an electromagnetic field guidance, and has reverse thorns on an inside wall surface of the curve ion duct. Accordingly, a novel macroparticle-filtered coating plasma source device is obtained. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0007]    The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention, taken in con junction with the accompanying drawings, in which 
           [0008]      FIG. 1  is the sectional view showing the preferred embodiment according to the present invention; 
           [0009]      FIG. 2A  to  FIG. 2D  are the views showing the first to the fourth duct segment combination; 
           [0010]      FIG. 3  is the enlargement view showing A of  FIG. 1 ; and 
           [0011]      FIG. 4A  to  FIG. 4C  are the views showing the welding positions of the guiding rods on the target. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]    The following description of the preferred embodiment is provided to understand the features and the structures of the present invention. 
         [0013]    Please refer to  FIG. 1 , which is a sectional view showing a preferred embodiment according to the present invention. As shown in the figure, the present invention is a macroparticle-filtered coating plasma source device, comprising a plasma source  10 , a curve ion duct  20 , a controller  30 , an arc power source  40  and a multi-channel power source  50 , where macroparticles in a plasma is filtered; a great number of ions are passed through a duct; and film adhesion and quality are enhanced. 
         [0014]    The plasma source  10  is set at an end of the curve ion duct  20 ; the plasma source  10  has a target  11  connected to a cathode of the arc power source  40 ; a guiding rod  111  is connected on a side surface of the target  11 ; and a trigger rod  163  is set at a nearby position on a wall of the curve ion duct  20  and is connected to an anode of a power source driven at outside of the wall of the curve ion duct  20 . The target is made of a solid metal, a metal alloy, graphite, silicon, boron metal oxide, a metal oxide, a metal carbide, a silicide or a metal silicide. 
         [0015]    A flash guard  12  is deposed under the target  11  with a floating connection and is connected with a target frange  131 . The target frange  131  has an electrical insulating plate  132  for fixing a target supporting rod  14  and being insulated. The target supporting rod  14  has a cooling water channel inside; and the cooling water channel is provided with cooling water from a water inlet  15  of the plasma source  10  to cool down the target  11 . An electromagnetic coil  161  outside the target flange  131  together with a driving rod  162  is welded with a trigger rod  163  in front of the driving rod  162  to obtain an arc-driving device, where the trigger rod  163  is moved forward to be in touch with the guiding rod  111  to drive an arc. The plasma source  10  has a metal anode duct wall  133  having a cooling water channel inside; and has reverse thorns  135  on an inner wall to avoid macro particles in plasma from escaping out of the duct. The reverse thorns are located on the inside wall forming a plurality of circles or being distributed randomly. An electromagnetic coil  134  outside the duct adjusts a surface magnetic field of the target  11  to maintain a stable discharge of the arc. The target  11  has an electrode connected with the cathode of the arc power source  40 . And the controller  30  controls a relay  60  for connecting the anode of the arc power source  40  to the driving rod  162  and the metal anode duct wall  133 . 
         [0016]    The curve ion duct  20  has a function of filtering macro particles in plasma. The curve ion duct  20  comprises three metal duct segments connected with each other through a flange  21  by fixing on a flange having a screw hole a buckle or a plurality of bolts and rabbets; and each two neighboring duct segments are separated with an electrical insulating plate (not shown in the figure.) The duct segment has a radius between 3 and 50 centimeters (cm), and two flanges at two ends of the duct segment obtain an angle between 10° and 180°. The duct segment has a cooling water channel inside and a water-and-electricity fast connector; has reverse thorns  22  on the inner wall to avoid macroparticles in plasma from escaping out of the duct; and has an electromagnetic coil  23  outside to drive ions in the duct to be biased to an ion source exit  24 . According to various requirements, the present invention controls the multi-channel power source  50  through the controller  30  to enhance ions amount with combinations of modules of various biases or various magnetic fields, where the multi-channel power source  50  comprises a plurality of power channels; and the controller performs processes of (a) deciding when an arc is started and how long the arc is lasted; (b) adjusting output power of each channel of the multi-channel power source; (c) comparing the output power of the channel with a default value; and (d) automatically adjusting the output power of the channel to obtain a best ion output. 
         [0017]    Please further refer to  FIG. 2A  to  FIG. 2D , which are views showing a first to a fourth duct segment combination. As shown in the figures, a curve ion duct  20  according to the present invention comprises duct segments and each duct segment has the same figure. Through various combinations of the duct segments, the curve ion duct  20  is extended in a 2-dimensional (2-D) level or a 3-dimensional (3-D) sphere. Therein, each duct segment has an individual electricity and magnetic field coil outside with various polarity through a floating connection, a anode connection or a cathode connection of bias to magnetic field, so that a path for a plasma is adjusted for largest amount of ions to pass through and best ion energy for deposition  FIG. 2A  to  FIG. 2C  are views showing three various 2-D combinations of five duct segments each of which has a 30 degrees (°) tilted angle; and  FIG. 2D  is a view showing a 3-D combination of five duct segments each of which has a 30° tilted angle. 
         [0018]    When using the present invention, air is exhausted out of the device first. Then a gas is fed in through a gas supplier  17  at the plasma source  120 . The target  11  is connected with the cathode of the arc power source  40 . The arc power source  40  is switched on and an arc current is produced through the trigger rod  163 . At the moment, arc pits move from top of the guiding rod  111  to a surface of the target  11  while wondering around with eruptions of ions to form a plasma. The plasma formed has macroparticles. When the plasma passes through the curve ion duct  20 , the duct segments has positive bias and a magnetic intensity at center area is kept steady to filter out 99 percents of macroparticles. And so a plasma without macro particles is obtained to be sputtered on a workpiece at the exit of the duct, where the workpiece is applied with a negative pulse bias. After a period of time, a metal film having a certain thickness is deposited. 
         [0019]    Please refer to  FIG. 3 , which is an enlargement view showing A of  FIG. 1 . As shown in the figure, a metal a node duct wall  133  of a plasma source according to the present invention has reverse thorns  135 . An included angle  1351  between a front surface of each reverse thorn and a surface of the metal anode duct wall, which is also an inside wall surface of a curve ion duct, has a degree between 10 degrees (°) and 90°. A sharp angle of the reverse thorn has a degree between 20° and 90°. And a distance between two neighboring reverse thorns is shorter than a half of a triangle height of the reverse thorn. 
         [0020]    Please refer to  FIG. 4A  to  FIG. 4C , which are views showing three welding positions of guiding rods on a target. As shown in the figures, three positions for a guiding rod  111  to be welded on the target  11  are shown. Regarding starting an arc, a first method is to push a trigger rod  163  toward a side of a target  11  by an arc-driving device. After reaching the target  11 , the trigger rod  163  is drawn back. Because the trigger rod  163  and the target  11  are respectively connected to a anode and a cathode of a direct current power, an arc is thus formed. In this way, a best design for a plasma sputtered without shielding is obtained. 
         [0021]    Another method for starting an arc is to weld a guiding rod  111 , having a diameter more than 2 millimeters, on a side surface of a target  11 , where the guiding rod  111  is made of the same material as the target  11 . Then the guiding rod  111  is connected to a position near an arc-driving device on a wall of a duct. A trigger rod  163  of an arc-driving device is directly connected with the guiding rod  111  to form an arc. At this moment, arc pits automatically move from top of the guiding rod  111  to the side surface of the target  11 . And then the arc spots wonder around the side surface of the target  11 . Because a size of a closed electromagnetic field in the arc space is minimized, the arc spots do not return back to the guiding rod  111 . 
         [0022]    To sum up, the present invention is a macroparticle-filtered coating plasma source device, where ion amount is enhanced and ion energy is controlled with combinations of modules of various biases or various magnetic fields; a speed for film deposition is improved; impurities in a film is reduced; and a film quality is enhanced. 
         [0023]    The preferred embodiment herein disclosed is not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present invention.