US20080105657A1

US20080105657A1 - Macroparticle-filtered coating plasma source device

Info

Publication number: US20080105657A1
Application number: US11/592,237
Authority: US
Inventors: Jin-Yu Wu; Ming-Ruesy Tsai; Shang-Feng Huang; Ding-Guey Tsai; Shin-Wu Wei; Chi-Fong Ai
Original assignee: Institute of Nuclear Energy Research
Current assignee: Institute of Nuclear Energy Research
Priority date: 2006-11-03
Filing date: 2006-11-03
Publication date: 2008-05-08

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

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

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.
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.
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' requests practically.

SUMMARY OF THE INVENTION

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.
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

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

FIG. 1 is the sectional view showing the preferred embodiment according to the present invention;

FIG. 2A to FIG. 2D are the views showing the first to the fourth duct segment combination;

FIG. 3 is the enlargement view showing A of FIG. 1; and

FIG. 4A to FIG. 4C are the views showing the welding positions of the guiding rods on the target.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following description of the preferred embodiment is provided to understand the features and the structures of the present invention.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.

Claims

1. A macro particle-filtered coating plasma source device, comprising:

a plasma source;

a curve ion duct, said curve ion duct connecting with said plasma source at an end;

a controller;

an arc source; and

a multi-channel power source,

wherein said curve ion duct comprises a plurality of duct segments and said duct segment has an individual electricity.

2. The device according to claim 1,

wherein said plasma source is exhausted through an opening to obtain a vacuum; and

wherein said opening is located on a place selected from a group consisting of a wall of said curve ion duct and a wall surrounding said target.

3. The device according to claim 1,

wherein said plasma source has a target, a trigger rod and a guiding rod.

4. The device according to claim 3,

wherein said target is made of a material selected from a group consisting of a solid metal, a metal alloy, graphite, silicon, boron metal oxide, a metal oxide, a metal carbide, a silicide and a metal silicide.

5. The device according to claim 1,

wherein said duct segment is curved, said duct segment has a radius between 3 and 50 centimeters (cm), and two flanges at two ends of said duct segment obtains an angle between 100 and 180°.

6. The device according to claim 1,

wherein said duct segment has a cooling water channel, an electromagnetic coil and a water-and-electricity fast connector.

7. The device according to claim 1,

wherein each two neighboring said duct segments are connected by fixing on a flange having a member selected from a group consisting of a screw hole, a buckle and a plurality of bolts and rabbets.

8. The device according to claim 1,

wherein said duct segment obtains an electrical polarity through a connection selected from a group consisting of a floating connection, a anode connection and a cathode connection.

9. The device according to claim 1,

wherein an electrical output for each duct segment is adjusted by said multi-channel power source;

wherein said multi-channel power source obtains an ion source by swiftly changing among said duct segments between a bias power source and a power source of an electromagnetic coil; and

wherein said ion source is selected from a pulse ion source and a direct-current ion source.

10. The device according to claim 1,

wherein an electrical insulating plate is located between every two neighboring said duct segments to obtain a high-energy ion source.

11. The device according to claim 1,

wherein said duct segments are assembled with an arrangement selected from a group consisting of a 2-dimensional arrangement and a 3-dimensional arrangement.

12. The device according to claim 1,

wherein said curve ion duct is cooled down with a cooling water;

wherein said curve ion duct has an electromagnetic field guidance; and

wherein said curve ion duct has reverse thorns on an inside wall surface of said curve ion duct.

13. The device according to claim 12,

wherein said reverse thorns are located on said inside wall in a way selected from a group consisting of forming a plurality of circles and being distributed randomly;

wherein each said reverse thorn has a sharp-triangle shape;

wherein an included angle between a front surface of said reverse thorn and said inside wall surface of said curve ion duct has a degree between 10 degrees (°) and 90°; and

wherein a sharp angle of said reverse thorn has a degree between 20° and 90°.

14. The device according to claim 11,

wherein said reverse thorn has a triangle height between 0.1 millimeter (mm) and 10 mm; and

wherein a distance between two neighboring reverse thorns is shorter than a half of a triangle height of said reverse thorn.

15. The device according to claim 1,

wherein said multi-channel power source comprises a plurality of power channels.

16. The device according to claim 1,

wherein said controller performs processes of:

(a) deciding when an arc is started and how long said arc is lasted;

(b) adjusting output power of each channel of said multi-channel power source;

(c) comparing said output power of said channel with a default value; and

(d) automatically adjusting said output power of said channel to obtain a best ion output.

17. The device according to claim 1,

wherein a anode of said arc source is connected to a target; and

wherein a cathode of said arc source is connected to a position selected from a group consisting of a wall surface of said plasma source, a duct segment of said curve ion duct, a flange at an exit of said curve ion duct, and a combination of the above positions.