Thin-film type common-mode choke coil and manufacturing method thereof

Abstract

A common-mode choke coil including a first magnetic substrate 1 , electrically insulating layers and coil pattern-including coil conductor layers 5 and 7 formed alternately on the first magnetic substrate 1 , and a second magnetic substrate 13 for covering an uppermost one of the electrically insulating layers, wherein: central regions of the electrically insulating layers surrounded by the coil patterns and portions of the electrically insulating layers corresponding to outer circumferential regions of the coil patterns are removed; a magnetic powder-containing resin (magnetic layer 11 ) is provided on the uppermost one of the electrically insulating layers and embedded in the removed portions of the electrically insulating layers; and the second magnetic substrate 13 is bonded to a flattened surface of the magnetic powder-containing resin by an adhesive layer 12.

What is claimed is:  
     
         1 . A common-mode choke coil comprising: 
 a first magnetic substrate;    multi-layer coil part in that electrically insulating layers and coil patterns formed alternately on said first magnetic substrate, the multi-layer coil part having a central portion surrounded by the coil patterns and an outer removal portion at where the electrically insulating layers corresponding to outer circumferential regions of the coil patterns are removed;    a magnetic powder containing region provided on the uppermost one of the electrically insulating layers and in the outer removal portion, a surface of the magnetic powder containing region being flattened; and    a second magnetic substrate on the flattened layer of the magnetic powder containing region through an adhesive.    
     
     
         2 . A common-mode choke coil array comprising a plurality of common-mode choke coils, each comprising: 
 a first magnetic substrate;    multi-layer coil part in that electrically insulating layers and coil patterns formed alternately on said first magnetic substrate, the multi-layer coil part having a central portion surrounded by the coil patterns and an outer removal portion at where the electrically insulating layers corresponding to outer circumferential regions of the coil patterns are removed;    a magnetic powder containing region provided on the uppermost one of the electrically insulating layers and in the outer removal portion, a surface of the magnetic powder containing region being flattened; and    a second magnetic substrate on the flattened layer of the magnetic powder containing region through an adhesive.    
     
     
         3 . A method of producing a common-mode choke coil, comprising the steps of: 
 forming electrically insulating layers and coil patterns alternately on a first magnetic substrate;    removing central regions of said electrically insulating layers surrounded by said coil patterns and portions of said electrically insulating layers corresponding to outer circumferential regions of said coil patterns;    applying a magnetic power-containing resin onto an uppermost one of said electrically insulating layers and embedding said magnetic power-containing resin in removed portions of said electrically insulating layers;    polishing a surface of said magnetic powder-containing resin after curing said magnetic powder-containing resin to flatten said surface; and    bonding a second magnetic substrate onto said flattened surface of said magnetic powder-containing resin by an adhesive agent.    
     
     
         4 . A method of producing a common-mode choke coil according to  claim 3 , wherein said magnetic powder-containing resin is applied and formed by a printing process.  
     
     
         5 . A method of producing a common-mode choke coil according to  claim 3 , wherein said magnetic power-containing resin provided by said coating step has a thickness not smaller than 1.5 times as large as a difference in level of said removed portions of said electrically insulating layers.  
     
     
         6 . A method of producing a common-mode choke coil according to  claim 3 , wherein said etching step is performed whenever one of said electrically insulating layers is formed.  
     
     
         7 . A thin-film type common-mode choke coil comprising: 
 a laminated structure having a magnetic substrate; and    electrically insulating layers and conductor layers laminated on said magnetic substrate in a direction of thickness,    wherein said conductor layers form at least two coil conductors; at least two of said conductor layers are provided as spiral conductor patterns; and said spiral conductor patterns satisfy the expression:    5  μm≦W 1≦36  μm      in which W1 is the conductor width of each of said spiral conductor patterns.    
     
     
         8 . A thin-film type common-mode choke coil according to  claim 7 , wherein said spiral conductor patterns satisfy the expression:  
       100  μm   2   ≦T*W 1  
       in which T is the conductor thickness of each of said spiral conductor patterns.  
     
     
         9 . A thin-film type common-mode choke coil according to  claim 7 , wherein said spiral conductor patterns satisfy the expression:  
         W 2 <T× 2  
       in which W2 is the space between said spiral conductor patterns, and T is the conductor thickness of each of said spiral conductor patterns.  
     
     
         10 . A thin-film type common-mode choke coil according to  claim 7 , wherein each of said spiral conductor patterns is composed of an undercoat conductor formed as a thin film, and a thickened conductor formed on said undercoat conductor and provided as a Cu-plating layer.  
     
     
         11 . A thin-film type common-mode choke coil according to  claim 10 , wherein said undercoat conductor is made of a combination of a lower layer of Cr and an upper layer of Cu or a combination of a lower layer of Ti and an upper layer of Cu.  
     
     
         12 . A thin-film type common-mode choke coil according to  claim 10 , wherein a surface of each of said spiral conductor patterns is covered with an Ni-plating film.  
     
     
         13 . A thin-film type common-mode choke coil according to  claim 7 , wherein an upper surface of said laminated structure is covered with a magnetic material.  
     
     
         14 . A thin-film type common-mode choke coil according to  claim 7 , wherein another magnetic substrate is bonded to an upper surface of said laminated structure.  
     
     
         15 . A thin-film type common-mode choke coil array comprising a plurality of thin-film type common-mode choke coils, each comprising: 
 a laminated structure having a magnetic substrate; and    electrically insulating layers and conductor layers laminated on said magnetic substrate in a direction of thickness,    wherein said conductor layers form at least two coil conductors; at least two of said conductor layers are provided as spiral conductor patterns; and said spiral conductor patterns satisfy the expression:    5  μm≦W 1≦36  μm      in which W1 is the conductor width of each of said spiral conductor patterns.