Vacuum arc evaporation apparatus and method, and magnetic recording medium formed thereby

Abstract

In a vacuum arc evaporation apparatus, to stably maintain vacuum arc discharge at an arc source when depositing a cathode material on a substrate, namely a magnetic recording medium, an ungrounded anode of a coil-type tube is placed inside an arc source discharge vacuum chamber. A DC arc power supply is connected between the cathode and the anode to cause an arc current to flow in the anode to generate a first magnetic field in one direction, from the cathode toward the anode. A second magnetic field is generated in the opposite direction, from the anode to the cathode by feeding a specified current to an external coil positioned around the discharge chamber. The external coil includes an around-cathode coil and an around-anode coil. The arc discharge can be started by operating a striker to carry out the deposition.

1 . A vacuum arc evaporation apparatus comprising: 
 a deposition vacuum chamber;    a discharge unit that discharges an arc of an ungrounded cathode target to form a cathode-material plasma; and    a plasma guiding unit disposed between the deposition vacuum chamber and the discharge unit for guiding the cathode-material plasma to the deposition vacuum chamber by an induced magnetic field to deposit the cathode target on the substrate,    wherein the discharge unit comprises an electrically grounded discharge vacuum chamber, a first generating unit provided inside the discharge vacuum chamber to generate a first magnetic field, and a second generating unit provided around the discharge vacuum chamber to generate a second magnetic field,    wherein the ungrounded cathode target is located in the discharge vacuum chamber.    
     
     
         2 . The vacuum arc evaporation apparatus according to  claim 1 , wherein the ungrounded cathode target is positioned away from the plasma guiding unit and the first generating unit is positioned between the plasma guiding unit and the cathode target.  
     
     
         3 . The vacuum arc evaporating apparatus according to  claim 2 , wherein the first magnetic field extends substantially along a first direction, and the second magnetic field extends substantially along a second direction, which is substantially opposite to the first direction.  
     
     
         4 . The vacuum arc evaporation apparatus according to  claim 2 , wherein the first direction extends substantially along a direction extending substantially from the cathode target toward the first generating unit, and the second direction extends substantially along a direction extending substantially from the first generating unit toward the cathode target.  
     
     
         5 . The vacuum arc evaporation apparatus according to  claim 1 , wherein the first generating unit is an electrically ungrounded coil-type anode provided along the inside of the discharge vacuum chamber, and the direction of the center axis of the coil-type anode is substantially parallel with the direction from the cathode target to the first generating unit.  
     
     
         6 . The vacuum arc evaporation apparatus according to  claim 1 , wherein the second generating unit is a coil provided along the outside of the discharge vacuum chamber, and the direction of the center axis of the coil is substantially parallel with the direction from the cathode target to the first generating unit.  
     
     
         7 . The vacuum arc evaporation apparatus according to  claim 1 , wherein the discharge vacuum chamber has a tubular shape and is provided with an insulating material between the inner surface of the discharge vacuum chamber and the first generating unit.  
     
     
         8 . The vacuum arc evaporation apparatus according to  claim 1 , further including a cooling unit for preventing the cathode target, the first generating unit, and the discharge vacuum chamber from being overheated by the arc discharge.  
     
     
         9 . The vacuum arc evaporation apparatus according to  claim 1 , wherein the deposition material is carbon.  
     
     
         10 . The vacuum arc evaporation apparatus according to  claim 1 , wherein the substrate has a magnetic recording layer.  
     
     
         11 . The vacuum arc evaporation apparatus according to  claim 10 , wherein the carbon is deposited on the magnetic recording layer to form an overcoat layer having a tetrahedral amorphous carbon structure with a high hardness.  
     
     
         12 . A method of depositing a film on to substrate, with a vacuum arc evaporation apparatus comprising: a deposition vacuum chamber; a discharge unit that discharges an arc of an ungrounded cathode target to form a cathode-material plasma; and a plasma guiding unit disposed between the deposition vacuum chamber and the discharge unit for guiding the cathode-material plasma to the deposition vacuum chamber by an induced magnetic field to deposit the cathode target on the substrate, wherein the discharge unit comprises an electrically grounded discharge vacuum chamber, a first generating unit provided inside the discharge vacuum chamber to generate a first magnetic field, and a second generating unit provided around the discharge vacuum chamber to generate a second magnetic field, wherein the ungrounded cathode target is located in the discharge vacuum chamber, the method comprising steps of: 
 evacuating the deposition vacuum chamber containing a substrate;    generating the cathode material plasma by arc discharging the cathode target with the discharge unit; and    depositing the cathode target on the substrate by guiding the cathode material plasma to the deposition vacuum chamber with the plasma guiding unit.    
     
     
         13 . The method according to  claim 12 , wherein the deposition material is carbon.  
     
     
         14 . The method according to  claim 12 , wherein the substrate has a magnetic recording layer and the cathode material is deposited on the magnetic layer as an overcoat layer.  
     
     
         15 . The method according to  claim 14 , wherein the deposition material is carbon to form the overcoat layer having a tetrahedral amorphous carbon structure with a high hardness.  
     
     
         16 . A magnetic recording medium formed by depositing the overcoat layer on the substrate with the magnetic layer according to the method of  claim 14 .  
     
     
         17 . A magnetic recording medium formed by depositing the carbon on the substrate with the magnetic layer according to the method of  claim 15 .  
     
     
         18 . A magnetic recording medium formed by the apparatus of  claim 10 .  
     
     
         19 . A magnetic recording medium formed by the apparatus of  claim 11.