Cathodic arc ignition device

Abstract

An arc striking device for cathode arc deposition of a target material onto a substrate, the arc striking device comprising a trigger finger movably arranged between a contact position and a static position, wherein in the contact position the trigger finger can physically contact the side surface of an adjacent target, while in the static position the adjacent target cannot be contacted by the trigger finger, wherein during cathode arc deposition of the target material, the trigger finger is movably arranged between the contact position and the static position so that contamination of the trigger finger by deposited target material during cathode arc deposition of the target material can be minimized.

Description

Technical Field

[0001] The present invention relates generally to physical vapor deposition apparatus and, more particularly, to arc starting devices, assemblies, and methods for cathodic arc deposition within a coating chamber. Background Art

[0002] Cathodic arc deposition is a known physical vapor deposition process. In order to perform the cathodic arc deposition process, a mechanism for igniting a high current discharge to produce evaporation of a target material placed in an arc evaporator (hereinafter also referred to as an arc evaporation source, arc source or spark source) is usually used, wherein the arc evaporator is placed in a vacuum chamber of a coating device. The arc evaporator usually includes a target material that can serve as a cathode during arc evaporation. The arc evaporator may also include at least one electrode that can serve as an anode during arc evaporation. In the case where the arc evaporator does not include any integrated anode, other electrodes placed in the vacuum chamber may also be used as anodes. It is also known that in some cases the vacuum chamber wall is used as an anode.

[0003] In order to start the cathodic arc deposition process, it is necessary to ignite an arc on the surface of the target material to be evaporated while using the target material to be evaporated as a cathode.

[0004] In arc deposition processes, substrates (eg workpieces such as components or tools) are processed under high vacuum, in particular in order to subject the substrates to plasma treatments such as plasma etching or coatings (eg coatings by means of cathodic arc physical vapor deposition processes).

[0005] Different types of ignition devices for arc evaporation sources are known and described, for example, in the US application No. US2011 / 0220495A1. It is explained there that the types of ignition devices can be divided into essentially three groups: a) devices for mechanically switching the contact between cathode and anode; b) devices for igniting the arc discharge by means of an electric spark discharge; c) devices for ignition by means of a conductive bridge.

[0006] In the arc deposition process, the substrate to be coated is placed in a coating chamber and the chamber is evacuated prior to coating deposition. As just described, an electric arc is used to evaporate material from a target surface, thereby providing coating material for coating deposition. The cathodic arc evaporation process begins with a high current, low voltage arc striking a target surface as a cathode, which produces electron emission from the target surface (acting as a cathode) to the anode.

[0007] As just mentioned above, the ignition of the arc can be achieved by using an ignition finger, which must be brought into contact with the target surface to be evaporated. Such an ignition finger is also commonly referred to as a trigger finger. Usually during the arc ignition, and sometimes even after the arc ignition, the ignition finger is exposed to the material evaporated from the target surface. This exposure leads to the formation of a coating film (such as a metal or ceramic film, such as a nitride film, an oxide film or other type of film) on the ignition finger. This film formation may weaken the ability of the ignition finger to perform its function (such as ensuring electrical contact and subsequent arc ignition). Therefore, routine maintenance is required to remove these unnecessary coatings. However, frequent maintenance shortens the working time, thereby reducing the overall efficiency of the coating manufacturing process. On the other hand, if maintenance is not performed frequently enough, not only will the ability of the ignition finger to perform the initial ignition be reduced, but the speed and reliability associated with any required reactivation will also be reduced. Thus, this also leads to reduced efficiency of the coating manufacturing process and may also lead to reduced coating quality. In operation, the cathode spot is only in an effective state for a short time, and then it automatically extinguishes and automatically re-ignites in a new area close to the previous cathode spot. This behavior causes a noticeable movement of the arc. When the cathode spot is completely extinguished and cannot be automatically re-ignited in a new area as described above, the arc is extinguished during the processing (i.e., a blackout period occurs). In this case, the ignition finger must be used again for reactivation to ignite a new arc on the target surface. Re-igniting a new arc by using a conventional ignition device with an ignition finger usually requires more than 50 milliseconds. Sometimes it is even necessary to shut down the entire process so that the ignition finger can be maintained, for example when the contact surface of the ignition finger is no longer suitable for ensuring electrical contact for igniting the arc due to unwanted coating material on the ignition finger, or when the ignition system needs maintenance for some other reason. Therefore, the known triggering devices including the known finger ignition system (i.e., the ignition system for igniting the arc at the target surface in the arc cathode evaporator) do not allow the trigger finger to be re-triggered quickly enough to obtain a rapid re-ignition of the arc. Unfortunately, the known system interrupts the arc evaporation process (causing a blackout time of more than 50 ms) based on the undesired extinguishing of the arc during the execution of the working process. Summary of the invention

[0008] The object of the present invention is to alleviate or overcome one or more difficulties associated with the prior art. In particular, the object of the present invention is to provide an arc starting device and an assembly for cathodic arc deposition to provide a simple and inexpensive arc starting device and cathodic arc deposition assembly that provides fast, high quality, reliable and low maintenance cathodic arc deposition.

[0009] In order to overcome these problems, the present invention provides an arc ignition device, a cathode arc deposition assembly and an arc initiation method for cathode arc deposition. The present invention particularly relates to an ignition device (hereinafter also referred to as an igniter) for igniting a high current discharge of an arc evaporator in a vacuum coating system (hereinafter also referred to as a vacuum coating device) .

[0010] The igniter provided by the present invention allows in particular to reduce or eliminate the maintenance required due to the formation of a coating film on the ignition finger in the igniter. In addition, the igniter according to the present invention allows the rapid regeneration of an arc that was accidentally extinguished, thereby eliminating any power outage period. In this regard, the term "rapid arc regeneration" refers to the re-ignition of the arc within a time period of 50ms or less, preferably within a time period between 20ms and 50ms. In a first aspect of the present invention, an ignition device for cathode arc deposition of a target material onto a substrate is disclosed, comprising a trigger finger movably arranged between a contact position and a rest position, wherein in the contact position the side surface of an adjacent target can be physically contacted by the trigger finger, while in the rest position the trigger finger cannot contact the adjacent target, wherein during cathode arc deposition of the target material, the trigger finger is so movably arranged between the contact position and the rest position that the contamination of the deposited target material by the trigger finger during cathode arc deposition can be minimized. In the context of the present invention, the trigger finger is preferably understood as a release unit that is essentially elongated, in particular rod-shaped. In particular due to the specific arrangement of the trigger finger according to the invention and due to the type and speed with which the trigger finger is moved between the contact position and the rest position, a minimization of contamination of the trigger finger according to the invention is achieved.

[0011] The arc ignition device according to the present invention can be placed in a vacuum chamber, in particular at the wall of the vacuum chamber, which preferably has a position for receiving one or more substrates to be coated. The vacuum chamber can preferably be evacuated to a predetermined pressure below atmospheric pressure (for example, less than 10Pa-the total pressure adjusted to complete the physical vapor deposition process is usually in the range between 0.01Pa and 8Pa, but this range should not be understood as a limitation of the present invention-the vacuum quality pressure range is generally divided into the following vacuum types: low: 760-0 Torr, medium: 0-10 -3 Support, height: 10 -3 -10 -8 Support, extra high: 10 -8 -10 -12 Support, very high: <10 -12 , Outer Space: ~10 -16 (Trust).

[0012] In an example of the first aspect, the arc-starting device comprises a housing, the arc-starting device being at least partially located in the housing, wherein the housing can be arranged outside a vacuum chamber that can be arranged adjacently. The housing can be fluidically connected to the interior of the chamber so that a vacuum exists in the housing or at least in a portion of the housing. In particular, the housing can be used for anti-fouling protection and provide electrical insulation. In addition, the arc-starting device can be maintained at the pressure level of the vacuum coating chamber by the housing in a simple and flexible manner.

[0013] In another example of the first aspect, the arc ignition device comprises an actuator for moving a trigger finger between a contact position and a rest position, wherein the trigger finger can be moved between the contact position and the rest position by the actuator in less than 50 ms, preferably between 50 ms and 20 ms, and more preferably between 20 ms and 10 ms. This rapid movement allows, in particular, rapid ignition and re-ignition of the arc. In view of effectively avoiding contamination by the deposited target material, the actuator can be designed to enable the trigger finger to leave the contact position after a maximum of 200 μs, preferably after a maximum of 150 μs, and in particular after a maximum of between 150 μs and 100 μs. The actuator can also preferably be configured to linearly move the trigger finger in the axial direction of the trigger finger.

[0014] In another example of the first aspect, the actuator is an electromagnetic actuator. In this case, the electromagnetic actuator can be arranged so as to generate an electromagnetic field to stretch the spring to a predetermined extension (stretching) length, so that the trigger finger moves from the rest position to the contact position. When the electromagnetic field is deactivated, the spring can return to its free length or preloaded length, so that the trigger finger moves back to its rest position. In order to ensure sufficient contact between the trigger finger and the side surface of the target, the inventors propose to generate a magnetic field that causes the spring to stretch corresponding to a distance that is greater than the actual distance traveled by the tip of the trigger finger when moving from the rest position to the contact position. For example, if the actual distance that the tip of the trigger finger needs to travel (between the rest position and the contact position) is 3 mm, a force should be provided that should produce the expected spring stretch and a corresponding stretch distance greater than 3 mm. This means that if no target is placed in the motion envelope of the tip of the trigger finger in the contact position, the force should be selected to provide an extension distance of, for example, 4 mm. In other words, the above-mentioned predetermined extension (elongation) length corresponds to the calculated or predetermined spring elongation, which will be the total distance that the compression spring travels from its free length or preloaded length to its extended (elongation) length when a preselected force acts on the compression spring and there are no obstacles in the way that hinder the spring elongation. This will be the case, for example, when an electromagnetic field force acts on the compression spring and there are no obstacles in the way.

[0015] In another example of the first aspect, the arc ignition device comprises a current limiting component for limiting the current during the contacting step to a value of less than 5 A, preferably to a value between 2 A and 5 A. The current limiting device can be used here in particular in connection with ignition and re-ignition of the arc in a material-saving manner.

[0016] In another example of the first aspect, the arc striking device includes a rod having a first end and an opposite second end, wherein the first end is preferably located within the adjacently disposed chamber and the second end is located within the housing.

[0017] In another example of the first aspect, the arc ignition device further comprises a spring (e.g., a tension spring) for moving the trigger finger to the rest position. Moving the trigger finger can preferably be accomplished by relaxing the spring tension force generated when the spring is stretched and the trigger finger is in the contact position. In particular, the use of a spring provides a simple design option for fast and precisely determinable movement of the trigger finger.

[0018] In another example of the first aspect, the trigger finger is at least partially composed of tungsten. The trigger finger can also be made of other conductive materials other than tungsten, but includes a trigger tip made of tungsten or tungsten alloyed with other materials as described below. Tungsten or tungsten alloyed material is used as a trigger finger or a trigger finger tip to act as a contact material (non-consumable electrode) to guide the current required to generate (ignite) the arc that will ignite on the target surface. Since pure tungsten electrodes are cost-effective but have poor heat resistance, different types of alloying elements can be used to influence the properties of tungsten, such as cerium, lanthanum or thorium. Tungsten alloyed materials are known to be used in TIG welding processes and usually contain the above-mentioned alloying elements in a concentration of not more than 2%. This type of tungsten alloyed material can be used to manufacture the trigger finger according to the present invention.

[0019] In a second aspect of the present invention, a component for cathode arc deposition of material onto a substrate is disclosed, the component comprising: the aforementioned arc striking device; a chamber for accommodating the substrate to be coated, the chamber being evacuated to a predetermined pressure below atmospheric pressure; a cathode back support disposed in the chamber; a target disposed adjacent to the cathode back support plate, the target having a first surface facing away from the cathode back support, a second surface spaced apart from the first surface and facing the cathode back support, and a side surface connecting the first and second surfaces, wherein plasma material will be ejected from the first surface.

[0020] In an example of the second aspect, the anode can be disposed within the chamber and spaced apart from the target. It is also feasible that the anode is outwardly away from the first surface of the target.

[0021] In another example of the second aspect, the trigger finger of the arc ignition device physically contacts the side surface of the target in the contact position, and the trigger finger does not contact the target in the static position.

[0022] In another example of the second aspect, particularly with respect to reliable protection against contamination of the trigger finger by the deposited target material, the assembly may further include a limiting member for protecting the trigger finger from contamination by the deposited material. The limiting member may be located within the chamber and may have a groove formed on its surface. Preferably, in the contact position, the first end of the trigger finger physically contacts the target, while in the static position, the first end of the trigger finger does not contact the target and is located in the groove of the limiting member to prevent the first end from being exposed to the deposited material. The limiting member may thus be located near the side surface of the target, preferably between the cathode back support and the anode. For example, the limiting member is annular, having a central opening defined by an inner side wall, wherein the groove extends from the outer side wall of the limiting member to the inner side wall in the radial direction of the limiting member. The diameter of the central opening may therefore be greater than the width of the target, so that the limiting member is arranged around the target.

[0023] In a third aspect of the present invention, a method of arc discharge for cathodic arc deposition of materials is disclosed, in particular using the aforementioned components, the method comprising the following steps: providing an anode and a target in a vacuum chamber; providing a trigger finger having a first end located in the chamber and a second end located outside the chamber; causing the trigger finger to move to a stationary position, wherein the first end of the trigger finger is accommodated in a restraining member so that the first end is away from the plasma material; shifting the trigger finger from the stationary position to a contact position, wherein the first end of the trigger finger is not located in the restraining member and wherein the first end physically contacts the side surface of the target; and moving the trigger finger back from the contact position to the stationary position.

[0024] In an example of the third aspect, in particular with regard to a structurally simple possible way of ensuring a fast and precisely definable movement of the trigger finger, the step of generating the movement of the trigger finger into the rest position can be accomplished by a spring, wherein the return of the trigger finger from the contact position to the rest position can be accomplished by a spring force for returning it to its free length.

[0025] In order to adjust the positioning of the trigger finger as precisely as possible, the step of displacing the trigger finger from the rest position to the contact position can be performed by an actuator located outside the chamber.

[0026] In another example of the third aspect, particularly with regard to the possible manner of rapid ignition and re-ignition of the arc, the amount of time that the trigger finger stays in the contact position is less than 250 μs, preferably less than 200 μs, and more preferably between 150 μs and 100 μs. With regard to minimizing the contamination of the trigger finger by the deposited target during arc deposition, the amount of time it takes for the trigger finger to move from the rest position to the contact position must not exceed 50 ms, preferably between 20 ms and 50 ms, and more preferably between 20 ms and 10 ms. In addition, for example, by adjusting the shift time to 20 ms, the trigger repetition (re-trigger) can correspond to a frequency of 50 Hz.

[0027] In a fourth aspect of the present invention, use of the aforementioned arc starting device in a pulsed cathodic arc deposition process is disclosed.

[0028] In a fifth aspect of the invention, the use of the aforementioned assembly in a pulsed cathodic arc deposition process is disclosed. The use of the arc ignition device according to the invention or the assembly according to the invention in a pulsed process is particularly suitable because of the re-ignition, which can be achieved as frequently and quickly as required due to the low contamination of the trigger finger. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic side cross-sectional view of a cathodic arc deposition assembly having an arc ignition device is shown with a trigger finger of the arc ignition device shown in a rest position.

[0030] Figure 2A Show Figure 1 A schematic top view of the restriction member is shown.

[0031] Figure 2B Show Figure 1 An isometric schematic diagram of the restraint shown.

[0032] Figure 3 Show Figure 1 A side cross-sectional schematic diagram of an assembly of , wherein the trigger finger is in the contact position as shown.

[0033] Figure 4 Graph showing electrical characteristics of one embodiment of a cathodic arc deposition assembly. DETAILED DESCRIPTION

[0034] Now referring to the accompanying drawings, Figure 1 A cathodic arc deposition assembly 100 is shown for depositing a coating (i.e., a material) on one or more substrates S to be coated. The cathodic arc deposition assembly 100 includes a chamber 102 defined by an outer housing 104. At least during operation of the cathodic arc deposition assembly 100, the chamber 102 is provided in a vacuum state. That is, the chamber 102 is evacuated to a predetermined pressure below atmospheric pressure (e.g., below 10 Pa - the total pressure adjusted to complete the physical vapor deposition process is generally in the range between 0.01 Pa and 8 Pa, but this range should not be construed as limiting the present invention - the vacuum quality pressure range is generally classified by the following vacuum types: low: 760-0 Torr, medium: 0-10 -3 Support, height: 10 -3 -10 -8 Support, extra high: 10 -8 -10 -12 Support, very high: <10 -12 , Outer Space: ~10 -16This is accomplished by a vacuum pump (not shown) disposed in fluid communication with chamber 102.

[0035] As further shown, a cathode backside support 106 is disposed within the chamber 102. A target 108 (i.e., a cathode) is located near the cathode backside support 106 and includes a first surface 108a, a second surface 108b spaced apart from the first surface 108a, and a side surface 108c connecting the first and second surfaces 108a, 108b. The target 108 is positioned so that the second surface 108b faces the cathode backside support 106 and the first surface 108a faces away from the cathode backside support 106. Specifically, the second surface 108b of the target 108 physically contacts the cathode backside support 106 so that the target 108 is placed thereon.

[0036] The anode 110 is located within the chamber 102 at a position spaced apart from the target 108. Specifically, the anode 110 is outwardly away from the first surface 108a of the target 108 so that the anode 110 is vertically disposed above the target 108. It should be understood that the disclosure herein is made with respect to a schematic diagram of a cathodic arc deposition assembly and the disclosure is not limited thereto. For example, while Figure 1 The schematic diagrams in and the disclosure thereto attached are made with respect to a vertical orientation (ie, target 108 is positioned above cathode backing plate 106 and anode 110 is spaced vertically above target 108), but it is contemplated that other orientations (eg, horizontal) are possible.

[0037] The target material (not shown) will be evaporated from the first surface 108a of the target 108, wherein a plasma is formed by the evaporated material, and the material is deposited onto the substrate S to be coated to form a coating. This is accomplished by providing a power supply 112 that generates and maintains the arc of the cathodic arc deposition assembly 100. Specifically, the positive terminal of the power supply 112 is operably connected to the anode 110, and the negative terminal of the power supply 112 is operably connected to the target 108 through the cathode back support 106. The power supply 112 provides an idle voltage in the range of 40V-200V.

[0038] To generate an arc, the target 108 is struck by a striking mechanism (i.e., a trigger finger, discussed further below); doing so creates a closed circuit from the power source 112 through the target 108 and the striking mechanism. When the striking mechanism disengages from the target 108, the circuit path between the striking mechanism and the target 108 is broken, causing the arc to jump the gap between the striking mechanism and the target 108, thereby initiating an arc on the target 108. When the arc is initiated, the arc path immediately extends between the target 108 and the anode 110 and is thereafter maintained by the power source 112.

[0039] Due to the high current levels flowing through the target 108 during operation, the target 108 may become very hot. Therefore, the cathodic arc deposition assembly 100 may include a cooling mechanism (not shown) designed to cool the target 108. The cooling mechanism may be integrally formed with the cathode backside support 106 or may be a separate independent feature.

[0040] like Figure 1 As further shown, the cathodic arc deposition assembly 100 includes an arc ignition device 114 designed to generate an arc. The arc ignition device 114 includes a housing 116 disposed outside the chamber 102 and a trigger finger 118 configured for linear movement in an axial direction X of the trigger finger 118. The housing 116 is attached to the housing cover 104 of the chamber 102 at an opening formed therein. Specifically, a seal is provided between the housing cover 104 and the housing 116 to sealably engage the former to the latter. The seal includes first and second sealing rings 120a, 120b that are in physical contact with the housing cover 104 and the housing 116, respectively. As further shown, an electrical insulator 122 is disposed between the first and second sealing rings 120a, 120b and is configured to electrically insulate the chamber 102 from the arc ignition device 114.

[0041] Although other actuators can be used (e.g. other forms of electromechanical actuators), an electromagnetic actuator is preferred because it allows the trigger finger to move while the moving parts of the actuator are in a vacuum (sealed and attached to the arc evaporation source) and the exciting electrical coil is in the atmosphere. Therefore, an arc ignition device construction with a very compact design can be achieved.

[0042] The arc ignition device 114 further comprises an actuator 124 disposed within the housing 116. The actuator 124 moves (i.e., translates) the trigger finger 118 between a rest position and a contact position, as will be explained below. Furthermore, the actuator 124 may be a mechanical actuator, but is preferably an electromagnetic actuator (e.g., a linear servo motor, a solenoid, etc.). Specifically, the actuator 124 may be in the form of an electromagnetic actuator, wherein the electromagnetic actuator generates mechanical motion after electrical excitation of a coil. The electrical excitation of the coil may be generated by discharging a capacitor (not shown). The actuator 124 may be activated in the form of pulses, giving the arc ignition device 114 a prescribed pulsed motion, whereby a repetition rate of up to 50 Hz is obtained.

[0043] Cathodic arc deposition assembly 100 also includes a restriction 126 located within chamber 102. Figure 2A and 2B As shown, the restriction 126 is preferably annular. However, other configurations are also conceivable. For example, the restriction 126 can be square or rectangular.

[0044] like Figure 2BAs shown, the outer peripheral surface of the restriction member 126 can be finished to include upper and lower chamfered edges 127a and 127b. In another example, the outer peripheral surface of the restriction member 126 can be finished to include rounded corners (such as radius corners). Alternatively, the outer peripheral surface can be unfinished (such as 90° square corners).

[0045] refer to Figure 2A and 2B , the limiter 126 includes a notch or groove 128. The groove 128 is formed in the limiter 126 and is configured to allow the trigger finger 118 to extend therethrough. Specifically, the limiter 126 is located near (preferably surrounding but not directly contacting) the side surface 108c of the target 108 and vertically between the cathode back support 106 and the anode 110. The lateral distance between the limiter and the target is preferably no greater than 1.5 mm (considering the radial distance). That is, the limiter 126 is located above the cathode back support 106 but below the anode 110. The limiter 126 is typically made of steel (magnetic or non-magnetic).

[0046] about Figure 2A and 2B , showing a schematic top view of the limiting member 126 ( Figure 2A ) and isometric diagram ( Figure 2B ). The restrictor 126 is annular and has an inner sidewall 126a and an outer sidewall 126b. The outer sidewall 126b of the restrictor may be formed to define a concave surrounding channel. However, the outer sidewall 126b may be finished to have a convex protrusion extending along the circumference of the outer sidewall 126b. Alternatively, the outer sidewall 126b may not include a circumferential channel. On the other hand, the outer sidewall 126b may be formed to include an outwardly extending ridge or flange extending along the circumference of the restrictor 126 (such as a retainer).

[0047] The groove 128 of the limiting member 126 extends from the inner side wall 126a to the outer side wall 126b in the radial direction of the limiting member 126. The limiting member must be designed to have a groove 128, the size of which is set to ensure that the trigger finger can pass through it without obstruction when moving therein. At the same time, the groove must be as narrow as possible to prevent the plasma from igniting therein, and in particular to avoid the deposition of coating material on the inner surface of the groove. This means that, for example, if a trigger rod with a diameter of 2 mm is used, the axial dimension of the groove 128 can be 3 mm, as schematically shown in FIG. 2b. In addition, the inner side wall 126a defines a central opening with a diameter d1 in the limiting member 126. The diameter d1 of the central opening is greater than the width W1 of the target 108, so that the limiting member 126 is arranged around the target 108. In other words, the limiting member 126 surrounds the target 108 in the circumferential direction, wherein the inner side wall 126a of the limiting member 126 faces the side surface 108c of the target 108.

[0048] Back to Figure 1, the trigger finger 118 is a rod having a first end 118a and an opposing second end 118b. The trigger finger 118, in particular the first end of the trigger finger (also referred to as the tip of the trigger finger), can be made of tungsten; alternatively, the trigger finger 118 can be made of other materials as described above. The trigger finger extends into the groove 128 of the limiter 126 and is arranged to abut the side surface 108c of the target 108. As shown in the figure, the second end 118b of the trigger finger is disposed within the housing 116 of the arc ignition device 114.

[0049] like Figure 1 As shown, the trigger finger 118 is shown in the rest position. Specifically, the first end 118a of the trigger finger 118 is located within the groove 128 of the limiter 126. In this way, the limiter 126 prevents the first end 118a of the trigger finger 118 from being exposed to any plasma material (e.g., from the arc ignition) disposed in the chamber 102. As further shown, a spring 130 is disposed within the housing 116 and is designed to produce movement of the trigger finger 118 to the rest position. The spring 130 is shown as a helical compression spring, and it is also contemplated that other types of springs (e.g., extension springs, conical springs, coil springs, etc.) and spring orientations may be used to produce movement of the trigger finger 118 to the rest position.

[0050] Go to Figure 3, the trigger finger 118 is in the contact position as shown. Specifically, as described above, the actuator 124 linearly displaces the trigger finger 118 from the rest position (i.e., the first end 118a of the trigger finger 118 is located in the groove 128) to the contact position, in which the first end 118a of the trigger finger 118 physically contacts the side surface 108c of the target 108. That is, the trigger finger 118 is movable (e.g., in a direction perpendicular to the imaginary plane in which the side surface 108c is located) to abut (i.e., contact) the side surface 108c of the target 108. This orientation and arrangement provides a small trigger finger movement, as opposed to abutting the first or second surface 108a, 108b of the target 108. The total distance that the trigger finger 118 moves between the rest position and the contact position may be, for example, 3 mm, but this distance should not be construed as a limitation of the present invention. The shorter the distance that the trigger finger must travel in the process of moving from the rest position to the contact position or vice versa, the shorter the time it takes to re-trigger. Likewise, if a shorter distance for the trigger finger to move is chosen, the efficiency can be higher and the system complexity can be reduced. Other advantages involved in using the trigger device (arc ignition device) according to the present invention are, for example, as follows: a) no corrosion of the side surface 108c occurs, so the use of the present invention ensures a stable trigger geometry; b) no coating film deposition or significantly reduced coating film deposition on the trigger finger (referring to the first end of the trigger finger or the tip of the trigger finger), because the movement of the trigger finger to the static position usually hides the trigger finger in the ignition device housing or in the limiter groove; c) a compact design, which includes the actuator and the components for the trigger function, including electrical isolation and vacuum sealing.

[0051] When the trigger finger 118 is in the contact position, a closed circuit is created from the power supply 112 through the target 108 and through the arc ignition device 114 (i.e., via the trigger finger 118). As shown, the cathodic arc deposition assembly 100 also includes a resistor 132 electrically connected to the trigger finger 118. The resistor 132 limits the current to no more than 5A during the contact position, preferably within the range of 2A-5A.

[0052] The operation of the cathodic arc deposition assembly 100 will now be described. Initially, the power supply 112 is activated, thereby providing an idle voltage of 40V-200V. At the same time, the trigger finger 118 is moved to a rest position by the spring 130. To generate an arc, the actuator 124 is activated (e.g., by energizing a coil by discharging a capacitor) such that the force provided by the actuator 124 to the trigger finger 118 is large enough to overcome the force of the spring 130 itself for maintaining its free length or preload length (also referred to as the spring relaxed length or relaxed attitude). In doing so, the trigger finger 118 is linearly displaced from the rest position to a contact position, wherein the first end 118a of the trigger finger 118 physically contacts the side surface 108c of the target 108.

[0053] It is noteworthy that the amount of time taken for the trigger finger 118 to move from the rest position to the contact position does not exceed 50 ms, and is preferably between 10 ms and 50 ms. When the first end 118a of the trigger finger 118 abuts the side surface 108c of the target 108, a closed circuit is formed, in which a current of 2A-5A is delivered. Thereafter, the actuator 124 is deactivated; thus, no force is applied to the trigger finger 118. Therefore, the trigger finger 118 moves back to the rest position under the force of the spring 130 itself to return to its free length. The amount of time that the trigger finger 118 remains in the contact position (i.e., the first end 118a of the trigger finger 118 is in contact with the side surface 108c of the target 108) does not exceed 100 μs, and is preferably less than 50 μs.

[0054] When the circuit is opened, the target 108 discharges an arc (i.e., plasma material). The plasma material is then directed to the substrate (e.g., by magnetic force) to coat the substrate S. In this manner, because the trigger finger 118 returns to the rest position immediately after the actuator 124 is deactivated (i.e., due to the spring 130's own force for generating its own relaxation) and because the first end 118a of the trigger finger 118 is seated in the recess 128 of the limiter 126 in the rest position, the trigger finger 118 avoids the plasma material. In other words, unless the actuator 124 is activated, the trigger finger 118 is always in the rest position (i.e., away from the plasma material). Therefore, the trigger finger 118 is not exposed to the plasma material, and thus film formation on the trigger finger 118 will not occur.

[0055] about Figure 4 , shows a graph of electrical characteristics of one embodiment of the cathodic arc deposition assembly 100. The graph is divided into a first time interval T1, a second time interval T2, and a third time interval T3. The first time interval T1 represents the cathodic arc deposition assembly 100 after the power source 112 has been activated but before an arc is generated. That is, in the first time interval T1, the trigger finger 118 is in a stationary position. The second time interval T2 represents the cathodic arc deposition assembly 100 in a contact position (i.e., as shown in FIG. 1 ). Figure 3 108). Specifically, the second time interval T2 occurs within 50 μs. That is, the amount of time that the first end 118a of the trigger finger 118 contacts the side surface 108c of the target 108 is equal to or less than 50 μs. The third time interval T3 represents arc generation, which occurs when the first end 118a of the trigger finger 118 is separated from the side surface 108c of the target 108. That is, the trigger finger 118 is again in a stationary position during the third time interval T3.

[0056] As shown, three lines (i.e., lines "A", "B", and "C") are arranged on the graph and represent the electrical characteristics of the cathodic arc deposition assembly 100 during each time interval (i.e., T1-T3). The first line "A" represents the arc discharge current (i.e., in amperes). Line "A" remains substantially constant during the first and second time intervals T1-T2, where the arc discharge current is equal to 0A. However, during the third time interval T3, the arc discharge current rises to 200A.

[0057] The second line "B" represents the amount of current (in amperes) at the trigger finger 118. As shown, during the first time interval T1, the trigger finger 118 experiences no current (i.e., 0A). During the second time interval T2, the trigger finger 118 experiences a current of 3A. The trigger current (i.e., line "B") is significantly reduced during the third time interval T3 but does not become zero (i.e., 0A).

[0058] Finally, the third line "C" represents the voltage (i.e., in volts) of the cathodic arc deposition assembly 100. During the first time interval T1, the voltage remains relatively constant and is approximately equal to 140V. This voltage is provided by the power supply 112. After the arc is generated (i.e., after the second time interval T2), the voltage decreases to a range of 20V-40V.

[0059] The present invention has been described with reference to the above embodiments. Others will think of modifications and alterations after reading and understanding this specification. The embodiments incorporating one or more aspects of the present invention are intended to cover all such modifications and alterations that fall within the scope of the appended claims.

Claims

1. An arc-starting device for depositing a target cathode arc onto a substrate, the arc-starting device comprising: a trigger finger, the trigger finger being movable between a contact position and a rest position, wherein in the contact position the trigger finger physically contacts a side surface of an adjacent target, and in the static position the adjacent target is not contacted by the trigger finger, wherein, during cathode arc deposition of the target material, the trigger finger can be movably arranged between the contact position and the static position, so that contamination of the deposited target material by the trigger finger during cathode arc deposition of the target material can be minimized, Wherein, the arc striking device comprises an actuator, and the actuator is used to move the trigger finger between the contact position and the rest position, wherein the trigger finger can be moved between the contact position and the rest position by the actuator in less than 50 ms.

2. The arc striking device according to claim 1, in, The arc striking device comprises a housing, wherein the arc striking device is at least partially located in the housing, In this case, the housing can be arranged outside a vacuum chamber which can be arranged adjacently.

3. The arc striking device according to claim 1 or 2, wherein: The trigger finger can be moved between the contact position and the rest position within a time of 20 ms to 50 ms.

4. The arc striking device according to claim 1 or 2, wherein: The trigger finger can be moved between the contact position and the rest position within a time of 10 ms to 20 ms.

5. The arc striking device according to claim 1, wherein: The actuator is designed such that the trigger finger leaves the contact position after a time of at most 200 μs.

6. The arc striking device according to claim 1, wherein: The actuator is designed such that the trigger finger leaves the contact position after a time of at most 150 μs.

7. The arc striking device according to claim 1, wherein: The actuator is designed such that the trigger finger can leave the contact position after a time of 100 μs to 150 μs at most.

8. The arc striking device according to claim 1, wherein: The arc striking device comprises a current limiting component which limits the current during the contacting step to a value less than 5A.

9. The arc striking device according to claim 8, wherein the current limiting component limits the current during the contacting step to a value between 2A and 5A.

10. The arc striking device according to claim 2, in, The arc striking device comprises a rod having a first end and an opposite second end, Wherein, the first end is located in adjacently arranged chambers and the second end is located in the housing.

11. The arc striking device according to claim 1, wherein: The actuator is configured to linearly move the trigger finger in an axial direction of the trigger finger.

12. The arc striking device according to claim 1, wherein: The arc striking device also includes a spring that moves the trigger finger to the rest position.

13. The arc striking device according to claim 1, wherein: The actuator is an electromagnetic actuator.

14. The arc striking device according to claim 1, wherein: The trigger finger is at least partially composed of tungsten.

15. An assembly for cathodic arc deposition of material onto a substrate, the assembly comprising: The arc striking device according to one of the preceding claims, a chamber for containing a substrate to be coated, the chamber being evacuated to a predetermined pressure below atmospheric pressure; a cathode back support disposed within the chamber; a target disposed adjacent to the cathode back support plate, the target having a first surface facing away from the cathode back support, a second surface spaced apart from the first surface and facing the cathode back support, and a side surface connecting the first surface and the second surface, wherein plasma material will be ejected from the first surface; an anode disposed within the chamber and spaced apart from the target, Wherein, in the contact position, the trigger finger of the arc ignition device physically contacts the side surface of the target, and in the static position, the trigger finger does not contact the target.

16. The assembly of claim 15, wherein: The anode is spaced outwardly from the first surface of the target.

17. An assembly according to claim 15 or 16, wherein The assembly also includes a limiter for protecting the trigger finger from contamination by deposited material.

18. The assembly of claim 17, wherein: The restrictor is disposed within the chamber and has a recess formed therein.

19. The assembly according to claim 18, in, In the contact position the first end of the trigger finger physically contacts the target, And wherein, in the rest position, the first end of the trigger finger does not contact the target and is located within the recess of the limiter to inhibit exposure of the first end to the deposition material.

20. The assembly of claim 17, wherein: The limiter is located adjacent to a side surface of the target and between the cathode back support and the anode.

21. The assembly according to claim 18, in, The restrictor is annular in shape and has a central opening defined by an inner side wall. Wherein, the groove extends from the outer side wall of the limiting member to the inner side wall in the radial direction of the limiting member.

22. The assembly of claim 21, wherein: The diameter of the central opening is greater than the width of the target so that the confinement member is disposed around the target.

23. The assembly of claim 15, wherein: The arc striking device includes a housing disposed outside the chamber.

24. A method for striking an arc for cathodic arc deposition of material using an assembly according to any one of claims 15 to 23, the method comprising the steps of: providing an anode and a target in a vacuum chamber; providing a trigger finger having a first end located within the chamber and a second end located outside the chamber; Producing movement of the trigger finger to a stationary position, wherein the first end of the trigger finger is received within a restraining member such that the first end is clear of plasma material; displacing the trigger finger from the rest position to a contact position, wherein the first end of the trigger finger is not within the restraint, and wherein the first end physically contacts a side surface of the target; and The trigger finger is moved back from the contact position to the rest position.

25. The method according to claim 24, in, The step of generating the movement of the trigger finger to the rest position is accomplished by a spring, And wherein the return movement of the trigger finger from the contact position to the rest position is accomplished by the force of a spring for returning to its free length.

26. The method according to claim 25, wherein: The step of displacing the trigger finger from the rest position to the contact position is accomplished by an actuator located outside the chamber.

27. The method according to any one of claims 24 to 26, wherein: The amount of time the trigger finger remains in the contact position is less than 250 μs.

28. The method according to any one of claims 24 to 26, wherein: The amount of time the trigger finger stays in the contact position is less than 200 μs.

29. The method according to any one of claims 24 to 26, wherein: The amount of time that the trigger finger stays in the contact position is between 100 μs and 150 μs.

30. The method according to any one of claims 24 to 26, wherein: The amount of time taken for the trigger finger to move from the rest position to the contact position does not exceed 50 ms.

31. The method according to any one of claims 24 to 26, wherein: The amount of time it takes for the trigger finger to move from the rest position to the contact position is between 20 ms and 50 ms.

32. The method according to any one of claims 24 to 26, wherein: The amount of time it takes for the trigger finger to move from the rest position to the contact position is between 20 ms and 10 ms.

33. Use of an arc ignition device according to any one of claims 1 to 14 in a pulsed cathodic arc deposition process.

34. Use of an assembly according to any one of claims 15 to 23 in a pulsed cathodic arc deposition process.

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