Wiring board and method for producing same

Abstract

The invention relates to a wiring board comprising a board having an electrode and being coated with an insulation layer with a hole for exposing the electrode; a wiring comprising a Cr or Ti layer, which is connected to the electrode and closely contacts with the insulation layer, and of a Cu layer which is closely contacts with the Cr or Ti layer; a protective film which covers the wiring and is provided with another hole for soldering; and a solder for the outer connection which is mounted in the both holes and brought to diffuse into the Cu layer to produce an alloy, and brought to reach the Cr or Ti layer thereby connecting the solder to the Cr or Ti layer.

1 . A wiring board comprising: 
 an insulation layer formed on the wiring board; and    a wiring comprising a Cu layer and a Cr or Ti layer which is arranged between the Cu layer and the insulation layer under the Cu layer in order to closely connect the Cu layer with the insulation layer,    wherein a solder for an outer connection is provided on the Cu layer and brought to diffuse into the Cu layer to produce an alloy, and brought to reach the Cr or Ti layer thereby connecting the solder to the Cr or Ti layer.    
   
   
       2 . A wiring board according to  claim 1 , wherein the solder is a Sn-containing solder.  
   
   
       3 . A wiring board according to  claim 1 , wherein the Cu layer has a thickness of from about 0.1 ÿm to about 10 ÿm.  
   
   
       4 . A wiring board according to  claim 1 , wherein the insulation layer comprises an organic resin layer.  
   
   
       5 . A wiring board according to  claim 1 , wherein the solder is directly connected to the wiring layer being connected to an electrode mounted on the board.  
   
   
       6 . A wiring board according to  claim 1 , wherein there is provided an Au or Ni/Au layer or a rustproof layer as preflux between the Cu layer and the solder in order to improve wettability of the solder.  
   
   
       7 . An electronic apparatus in which solder in the board according to  claim 1  is connected to an electronic component.  
   
   
       8 . A wiring board comprising: 
 a board having disposed thereon an electrode and an insulation layer disposed atop the electrode, the insulation layer having a first opening to expose the electrode;    a wiring comprising a Cr or Ti layer and a Cu layer in contact with the Cr or Ti layer, the Cr or Ti layer in contact with the electrode and with the insulation layer;    a protective film which covers the wiring and is provided with a second opening; and    a solder for the outer connection disposed in the second opening and brought to diffuse into the Cu layer to produce an alloy, and brought to reach the Cr or Ti layer thereby connecting the solder to the Cr or Ti layer.    
   
   
       9 . A wiring board according to  claim 8 , wherein the solder is a Sn-containing solder.  
   
   
       10 . A wiring board according to  claim 8 , wherein the Cu layer has a thickness of from about 0.1 ÿm to about 10 ÿm.  
   
   
       11 . A wiring board according to  claim 8 , wherein a Cr layer is provided between the Cu layer and the protective film.  
   
   
       12 . A wiring board according to  claim 8 , wherein the insulation layer comprises an organic resin layer.  
   
   
       13 . A wiring board according to  claim 8 , wherein there is provided an Au or Ni/Au layer or a rustproof layer as preflux between the Cu layer and the solder in order to improve wettability of the solder.  
   
   
       14 . An electronic apparatus in which the solder in the board according to  claim 8  is connected to an electronic component.  
   
   
       15 . A method of producing a wiring board, which comprises the following steps: a step of forming an insulation layer on a wiring board; 
 a step of forming a wiring, in which a Cr or Ti layer and a Cu layer are laminated on the insulation layer; and    a reflow bonding step, in which a solder for an outer connection is provided on the Cu layer and brought to diffuse into the Cu layer to produce an alloy, and brought to reaches the Cr or Ti layer thereby connecting the solder to the Cr or Ti layer.    
   
   
       16 . A method of producing a wiring board, which comprises the following steps: 
 a step of forming an insulation film, which comprises coating a wiring board having an electrode by the insulation film and forming an opening in the insulation film in order to expose the electrode;    a step of forming a wiring, in which a Cr or Ti layer is connected to the electrode and in physical contact with the insulation film, and in which a Cu layer is disposed on the Cr or Ti layer;    a step of forming a protective film, which comprises coating the wiring with the protective film and forming an opening in the protective film for soldering; and    a reflow bonding step, in which a solder for the outer connection is provided within the opening of the protective film and caused to diffuse into the Cu layer in the wiring to produce an alloy and to reach the Cr or Ti layer thereby connecting the solder to the Cr or Ti layer.    
   
   
       17 . A semiconductor device comprising: 
 a semiconductor board having an electrode and being coated with an insulation layer being formed with an opening in order to expose the electrode; a wiring comprising a Cr or Ti layer which is in close contact with the insulation layer and of a Cu layer which is closely laminated on the Cr or Ti layer;    a protective film covering the wiring and being formed with an opening for soldering; and    a solder for an outer connection which is provided within the opening of the protective film and brought to diffuse into the Cu layer in the wiring to produce an alloy and brought to reach the Cr or Ti layer thereby connecting the solder to the Cr or Ti layer.    
   
   
       18 . A semiconductor device according to  claim 17 , wherein a Cr layer is provided between the Cu layer and the protective film.  
   
   
       19 . A semiconductor device according to  claim 17 , wherein the insulation layer comprises an organic resin layer.  
   
   
       20 . A semiconductor device package structure in which the solder for an outer connection in the semiconductor device according to  claim 17  is connected to an electronic component.