A self-ignition structure of a non-ignition needle type PVD multi-arc ion plating

Abstract

This invention discloses a self-arc ignition structure for PVD multi-arc ion plating without an arc-starting needle, relating to the field of ion plating technology. It includes a target material, a pressure ring, and a ceramic gasket. The ceramic gasket is disposed between the target material and the pressure ring, and a conductive liquid layer is disposed on the surface of the ceramic gasket. The pressure ring and the target material are in contact with the conductive liquid layer, thereby forming a micro-conductive connection structure between the target material and the pressure ring. This invention enables extremely simplified, pollution-free, and highly reliable low-voltage automatic arc ignition.

Description

Technical Field

[0001] This invention relates to the field of ion plating technology, and in particular to a self-arc-initiating structure for PVD multi-arc ion plating without arc-initiating needles. Background Technology

[0002] Multi-arc ion plating is one of the most widely used vacuum coating processes in the physical vapor deposition (PVD) technology system. Its working principle involves using a vacuum arc discharge to form a high-density cathode arc spot on the target surface. Under the high temperature of the arc spot, the target material rapidly evaporates and becomes highly ionized, subsequently depositing a dense functional coating on the workpiece surface. With its core advantages such as high ionization rate, fast deposition rate, excellent film adhesion, good coating wrap-around properties, and wide process adaptability, multi-arc ion plating technology has been widely applied in high-end manufacturing fields such as precision molds, cutting tools, aerospace components, key automotive parts, and semiconductor protective coatings. It is one of the key processes for preparing hard coatings and functional protective coatings. As downstream manufacturing industries continue to upgrade towards higher precision, higher cleanliness, and longer lifespan, multi-arc ion plating equipment faces increasingly stringent requirements in terms of coating purity control, process stability, and continuous production reliability.

[0003] In existing multi-arc ion plating equipment, the mainstream arc ignition method still relies on mechanical arc-ignition needle contact. This method uses a cylinder or electromagnetic drive mechanism to reciprocate the extension and retraction of a metal arc-ignition needle, causing the needle to make instantaneous physical contact with the target surface and then quickly detach. The sudden change in electric field generated at the moment of contact separation breaks down the rarefied gas in the vacuum chamber, thereby igniting the electric arc on the target surface. However, this structure has insurmountable technical defects in long-term engineering applications: the arc-ignition needle repeatedly contacts the target under high temperature and high ion bombardment environment, and its tip is prone to wear, deformation, ablation, and even adhesion. The arc ignition success rate continues to decline with the use time, and the resulting failures such as dry triggering and arc interruption directly restrict the continuous and stable operation of the equipment. At the same time, metal debris and high-temperature oxidation impurities detached from the arc-ignition needle will enter the vacuum chamber and deposit on the target surface or film layer, resulting in quality defects such as particles, pinholes, and dirt spots in the coating, which seriously affects the batch consistency and cleanliness level of high-precision coated products.

[0004] To avoid the wear and contamination problems caused by mechanical arc-initiating needles, the industry has gradually developed non-contact pulse arc-initiating technology, which uses a high-voltage pulsed electric field to directly break down the vacuum gap to achieve non-contact arc initiation. This type of solution eliminates the physical contact between the arc-initiating needle and the target material, thus eliminating mechanical wear and contamination sources at the source and improving arc cleanliness to a certain extent. However, in practical applications, existing non-contact pulse arc-initiating technologies still require additional configuration of dedicated high-voltage trigger electrodes, independent high-voltage pulse generation modules, and supporting signal control systems. The equipment has low integration, complex assembly structure, and high modification costs. Moreover, the trigger electrodes are mostly customized special structures, which are difficult to be compatible with the standard installation system of conventional multi-arc ion plating target holders, greatly limiting the compatibility and versatility of new and old equipment. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a self-arc-initiating structure for PVD multi-arc ion plating without arc-initiating needles, achieving extremely simplified, pollution-free, and highly reliable low-pressure automatic arc initiation.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A self-arc-initiating structure for PVD multi-arc ion plating without arc-initiating needles includes a target material, a pressure ring, and a ceramic pad. The ceramic pad is disposed between the target material and the pressure ring, and a conductive liquid layer is disposed on the surface of the ceramic pad. The pressure ring and the target material are respectively in contact with the conductive liquid layer, so that a micro-conductive connection structure is formed between the target material and the pressure ring.

[0008] Preferably, the device further includes a magnetic shield, the target material is disposed inside the magnetic shield, the ceramic gasket is disposed between the magnetic shield and the target material, and the pressure ring presses the ceramic gasket tightly against the target material.

[0009] Preferably, a plurality of ceramic pads are provided, and the plurality of ceramic pads are spaced apart between the magnetic shield and the target material.

[0010] Preferably, four ceramic pads are provided, and the four ceramic pads are spaced apart circumferentially along the magnetic shield.

[0011] Preferably, the ceramic gasket is fixed to the magnetic shielding cover by screws, the conductive liquid layer covers the surface of the ceramic gasket and the surface of the screws; the magnetic shielding cover is made of soft iron.

[0012] Preferably, the pressure ring presses the ceramic gasket against the target material.

[0013] Preferably, the target and the pressure ring are electrically connected to different electrodes of a pulse bias power supply, which is used to apply a pulse bias between the target and the pressure ring.

[0014] The present invention has the following beneficial effects:

[0015] I. Improving Arc Ignition Cleanliness and Eliminating Coating Contamination Sources: This solution involves setting a conductive liquid layer on the surface of the ceramic gasket, creating a micro-conductive connection between the target and the pressure ring. This electrical conductivity replaces the traditional mechanical contact separation between the arc-ignition needle and the target. Since there is no direct contact between the metal needle tip and the target surface during the entire arc ignition process, the problem of metal debris and oxide impurities caused by high-temperature ablation, wear, or adhesion of the arc-ignition needle entering the vacuum chamber is fundamentally eliminated. This significantly reduces the probability of defects such as particles, pinholes, and dirt spots in the coating, improving batch consistency and surface cleanliness of high-precision coated products. This effect has direct improvement significance for processes with extremely sensitive cleanliness requirements, such as semiconductor protective coatings, precision optical films, and high-end decorative films.

[0016] II. Improving Long-Term Operational Stability and Arc Ignition Success Rate: Traditional mechanical arc ignition needles inevitably experience wear, deformation, or ablation at the tip after repeated contact with high-temperature targets, leading to fluctuations in contact resistance and unstable separation. Consequently, the arc ignition success rate declines continuously with equipment operation time. This solution maintains a stable and controllable micro-conduction state between the target and the pressure ring through a conductive liquid layer. Arc ignition conditions no longer depend on the geometric integrity of the mechanical needle tip and contact pressure, avoiding no-trigger and arc-breaking failures caused by arc ignition needle performance degradation. In continuous batch production scenarios, this structure can maintain the repeatability and reliability of arc ignition actions over a long period, reducing equipment downtime and process interruptions caused by arc ignition failures, thus improving overall production efficiency and equipment utilization.

[0017] Third, the invention simplifies the equipment structure and reduces system modification costs. Existing contactless pulse arc ignition solutions require additional dedicated high-voltage trigger electrodes, independent high-voltage pulse generation modules, and supporting signal control systems, resulting in complex internal structures of the vacuum chamber, difficult assembly and maintenance, and significantly increased equipment manufacturing costs. This invention achieves self-arc ignition using only a target material, pressure ring, ceramic gasket, and conductive liquid layer, eliminating the need for additional dedicated high-voltage electrodes or independent pulse modules, thus significantly simplifying the overall structure. Furthermore, this structure is compatible with the standard installation system of conventional multi-arc ion plating target holders, requiring minimal modification to existing equipment and reducing adaptation difficulty, effectively lowering the economic and engineering implementation costs of upgrading old and new equipment to arc-free systems.

[0018] IV. Eliminating Moving Parts and Reducing the Risk of Mechanical Failure: Existing mechanical arc ignition solutions include cylinders or electromagnetic drive mechanisms and reciprocating arc-ignition needle assemblies. These moving parts are prone to jamming, seal failure, or drive malfunction in high-temperature vacuum and ion bombardment environments, making them key areas for equipment maintenance and frequent points of failure. This solution uses static micro-conductive connections to achieve arc ignition. The entire arc ignition structure contains no reciprocating moving parts, eliminating potential sources of failure such as mechanical wear, movement obstruction, and seal aging caused by moving parts from a design perspective. This improves the mechanical reliability and ease of maintenance of vacuum coating equipment under long-term operating conditions.

[0019] V. Combining Shielding Protection and Target Stability Support: This structure further incorporates a magnetic shield, with ceramic gaskets spaced between the shield and the target, secured by a pressure ring. The magnetic shield, made of soft iron, effectively constrains the magnetic field distribution around the target, reducing abnormal discharges in non-target areas, suppressing arc spot drift towards the target edge or target base, and improving the stability of the arc spot's movement on the target surface. Simultaneously, multiple ceramic gaskets, spaced circumferentially, work in conjunction with the conductive liquid layer to provide a micro-conductive path between the target and the pressure ring, while maintaining the target's stable positioning and reliable clamping within the magnetic shield. This prevents the target from loosening or shifting during the coating process, thus combining arc initiation and structural fixation functions.

[0020] VI. Improved low-voltage arc ignition characteristics and reduced power supply requirements: The target and pressure ring are electrically connected to different electrodes of the pulse bias power supply. The micro-conductive connection structure formed by the conductive liquid layer enables the generation of a local concentrated electric field when pulse bias is applied, which can induce vacuum discharge and ignite the target surface arc under relatively low voltage conditions. This characteristic reduces the dependence on a dedicated high-voltage arc ignition power supply, allowing the entire arc ignition process to be completed within the voltage range of a conventional pulse bias power supply. This further reduces the additional investment in power systems and electrical safety, while also helping to shorten the arc ignition response time and improve process cycle efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention (excluding the magnetic shielding cover).

[0023] Figure 2 This is a schematic diagram showing the state of the ceramic gasket with a conductive liquid layer according to an embodiment of the present invention.

[0024] Figure 3 This is a partial schematic diagram of the magnetic shielding cover with ceramic plates added according to an embodiment of the present invention.

[0025] 㕜:1. Target material; 2. Pressure ring; 3. Ceramic gasket; 4. Magnetic shielding cover. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] like Figures 1 to 3 As shown, a self-arc-initiating structure for PVD multi-arc ion plating without arc-initiating needles includes a target material 1, a pressure ring 2, and a ceramic pad 3. The ceramic pad 3 is disposed between the target material 1 and the pressure ring 2, and a conductive liquid layer is disposed on the surface of the ceramic pad 3. The pressure ring 2 and the target material 1 are in contact with the conductive liquid layer, so that a micro-conductive connection structure is formed between the target material 1 and the pressure ring 2.

[0028] like Figures 1 to 3 As shown, a ceramic gasket 3 is disposed between the target 1 and the pressure ring 2. Its surface is coated or covered with a conductive liquid layer. The pressure ring 2 and the target 1 are in contact with this conductive liquid layer, thereby forming a micro-conductive electrical connection path between the target 1 and the pressure ring 2. This micro-conductive connection is not a complete short circuit, but rather a weakly conductive channel with a relatively high resistance value. When a pulsed bias power supply applies a voltage between the target 1 and the pressure ring 2, due to the presence of the micro-conductive connection, local current concentration and electric field enhancement occur near the contact interface between the ceramic gasket 3 and the target 1, triggering micro-area discharge or electron emission. This achieves initial arc ignition without the need for mechanical arc-igniting needle contact separation. The conductive liquid layer replaces the instantaneous contact function between the arc-igniting needle and the target 1, transforming mechanical action into static electrical conduction behavior, thus eliminating wear and contamination problems caused by moving parts in principle.

[0029] It should be noted that the conductive liquid layer should have a sufficiently low saturated vapor pressure in a vacuum environment to avoid contaminating the vacuum cavity or affecting the purity of the film due to liquid evaporation. Simultaneously, the resistivity of the conductive liquid layer needs to be matched according to the distance between the target 1 and the pressure ring 2 and the applied voltage, so that the micro-conduction current can meet the requirements of local electric field enhancement without forming a continuous large current bypass that would affect the normal arc discharge process.

[0030] like Figures 1 to 3As shown, the target 1 is housed within a magnetic shield 4, which is made of soft iron. Soft iron possesses high magnetic permeability, effectively confining and redistributing stray magnetic fields around the target 1, concentrating the magnetic field primarily on the discharge region near the target surface. During multi-arc ion plating, the movement of the cathode arc spot is significantly affected by the magnetic field distribution on the target surface. By guiding and limiting the magnetic field through the magnetic shield 4, abnormal discharges at the edges and target base of the target 1 can be reduced, and the drift of the arc spot to the non-coating area can be suppressed, maintaining a relatively uniform and stable movement of the arc spot within the working area of ​​the target surface. This effect improves the etching uniformity of the target 1, reduces edge ablation, and extends the service life of the target 1.

[0031] Multiple ceramic pads 3 are spaced apart between the magnetic shield 4 and the target material 1, with four ceramic pads 3 preferably evenly distributed around the circumference of the magnetic shield 4. On the one hand, the multiple ceramic pads 3 collectively provide micro-conductive electrical connection points between the target material 1 and the pressure ring 2, enabling the formation of local electric field enhancements at multiple locations during arc ignition, thus improving the success rate and uniformity of arc ignition. On the other hand, as rigid insulating spacers, the ceramic pads 3, under the pressure of the pressure ring 2, stably support and position the target material 1 within the predetermined position of the magnetic shield 4, preventing displacement or vibration of the target material 1 during the coating process due to thermal expansion, electromagnetic force, or arc spot impact. The circumferential uniform distribution ensures that the supporting force and electrical connection conditions around the target material 1 are consistent, avoiding target material 1 skewing and local arc spot aggregation caused by uneven force or asymmetrical electric field distribution.

[0032] The ceramic gasket 3 is fixed to the magnetic shielding cover 4 by screws, and the conductive liquid layer covers not only the surface of the ceramic gasket 3 but also the surface of the screws. This screw fastening method ensures reliable mechanical positioning of the ceramic gasket 3 on the magnetic shielding cover 4, preventing displacement during the installation, removal, or coating of the target material 1. With the conductive liquid layer covering the screw surface, the screw itself also participates in the micro-conductive connection, expanding the effective contact area between the conductive liquid layer and the pressure ring 2 or the target material 1, reducing random fluctuations in contact resistance, and improving the stability of the micro-conductive connection. Simultaneously, covering the screw prevents uncontrollable arcing points from forming on the exposed screw surface, reducing the risk of abnormal discharge at the screw location.

[0033] Target 1 and pressure ring 2 are electrically connected to different electrodes of a pulsed bias power supply, which applies a pulsed bias between them. Since a micro-conductive connection is formed between target 1 and pressure ring 2 through a conductive liquid layer, when the pulsed bias arrives, current preferentially flows through the micro-conductive path formed by the conductive liquid layer, generating localized Joule heating and field electron emission, thereby initiating vacuum discharge under low-voltage conditions. This low-voltage pulse triggering method avoids dependence on a dedicated high-voltage pulse generation module, allowing the arc initiation process to be integrated into a conventional bias power supply circuit. The pulsed bias can also automatically adjust the arc maintenance conditions after arc initiation, reducing damage to the micro-conductive structure from continuous high current and ensuring that subsequent arc discharge mainly occurs on the target surface rather than in the ceramic pad 3 area.

[0034] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A self-arc-initiating structure for PVD multi-arc ion plating without arc-initiating needles, characterized in that, The device includes a target (1), a pressure ring (2), and a ceramic gasket (3). The ceramic gasket (3) is disposed between the target (1) and the pressure ring (2). A conductive liquid layer is disposed on the surface of the ceramic gasket (3). The pressure ring (2) and the target (1) are in contact with the conductive liquid layer, so that a micro-conductive connection structure is formed between the target (1) and the pressure ring (2).

2. The arc-initiating needle-type PVD multi-arc ion plating self-arc-initiating structure according to claim 1, characterized in that, It also includes a magnetic shield (4), the target material (1) is disposed inside the magnetic shield (4), the ceramic gasket (3) is disposed between the magnetic shield (4) and the target material (1), and the pressure ring (2) presses the ceramic gasket (3) against the target material (1).

3. The arc-initiating needle-type PVD multi-arc ion plating self-arc-initiating structure according to claim 2, characterized in that, Multiple ceramic pads (3) are provided, and the multiple ceramic pads (3) are spaced apart between the magnetic shield (4) and the target material (1).

4. The arc-initiating needle-type PVD multi-arc ion plating self-arc-initiating structure according to claim 3, characterized in that, Four ceramic pads (3) are provided, and the four ceramic pads (3) are spaced apart along the circumference of the magnetic shield (4).

5. The arc-initiating needle-type PVD multi-arc ion plating self-arc-initiating structure according to claim 2, characterized in that, The ceramic gasket (3) is fixed to the magnetic shield (4) by screws. The conductive liquid layer covers the surface of the ceramic gasket (3) and the surface of the screws. The magnetic shield (4) is made of soft iron.

6. The arc-initiating needle-type PVD multi-arc ion plating self-arc-initiating structure according to claim 1, characterized in that, The pressure ring (2) presses the ceramic gasket (3) against the target material (1).

7. The arc-initiating needle-type PVD multi-arc ion plating self-arc-initiating structure according to claim 1, characterized in that, The target (1) and the pressure ring (2) are electrically connected to different electrodes of the pulse bias power supply, which is used to apply a pulse bias between the target (1) and the pressure ring (2).

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