Hybrid wiring board, semiconductor apparatus, flexible substrate, and fabrication method of hybrid wiring board

Abstract

A first via land of a wiring layer on a first surface of a first insulation layer that is a rigid layer and a second via land of a wiring layer on a second surface of a second insulation layer that is a flexible layer are electrically and mechanically connected with a conductive pillar pierced through a third insulation layer disposed between the first insulation layer and the second insulation layer. In such a structure, a wiring board that can mount a highly integrated semiconductor device, that is small and thin, and that has high reliability can be accomplished.

What is claimed is:  
     
         1 . A hybrid wiring board, comprising: 
 a first wiring substrate having a first face and a second face, and the first wiring substrate having a first wiring layer formed onto the first face;    a second wiring substrate having a first face and a second face, and the second wiring substrate having a second wiring layer formed onto the second face;    an insulating resin layer interposed between the first face of the first wiring substrate and the second face of the second wiring substrate; and    at least a conductive pillar pierced through the insulating resin layer so as to connect the first wiring layer and the second wiring layer.    
     
     
         2 . A hybrid wiring board as set forth in  claim 1 , wherein the first wiring layer and the second wiring layer are intruded into the insulating resin layer.  
     
     
         3 . A hybrid wiring board as set forth in  claim 1 , wherein the first wiring substrate is rigid and the second wiring substrate is flexible.  
     
     
         4 . A hybrid wiring board as set forth in  claim 1 , wherein the first wiring substrate and the second wiring substrate are flexible.  
     
     
         5 . A hybrid wiring board as set forth in  claim 1 , wherein the first wiring substrate and the second wiring substrate are rigid.  
     
     
         6 . A hybrid wiring board as set forth in  claim 1 , wherein the insulating resin layer is rigid.  
     
     
         7 . A hybrid wiring board as set forth in  claim 1 , wherein the first wiring layer having a first via land, the second wiring layer having a second via land, and the conductive pillar connects the first via land and the second via land.  
     
     
         8 . A hybrid wiring board as set forth in  claim 1 , wherein the first wiring substrate has a plurality of wiring layer and at least an insulating layer.  
     
     
         9 . A hybrid wiring board as set forth in  claim 8 , wherein the wiring layers of the first wiring substrate are interconnected by a conductive pillar piercing thorough the insulating layer of the first wiring substrate.  
     
     
         10 . A hybrid wiring board as set forth in  claim 1 , wherein the second wiring substrate has a plurality of wiring layer and at least an insulating layer which is flexible.  
     
     
         11 . A hybrid wiring board, comprising: 
 a first insulating layer having a first face and a second face, and the first insulating layer having a first flexibility;    a first wiring layer formed onto the first face of the first insulating layer;    a second insulating layer having a first face and a second face, and the second insulating layer having a second flexibility which is larger than the first flexibility,    a second wiring layer formed onto the second face of the second insulating layer;    a third insulating layer interposed between the first face of the first insulating layer and the second face of the second insulating layer, and the third insulating layer having a third flexibility which is smaller than the second flexibility; and    a conductive pillar pierced through the insulating resin layer so as to connect the first wiring layer and the second wiring layer.    
     
     
         12 . A hybrid wiring board as set forth in  claim 11 , wherein a bonding strength between the second insulating layer and the third insulating layer is larger than a bonding strength obtained when the first insulating layer and the third insulating layer are bonded.  
     
     
         13 . A hybrid wiring board as set forth in  claim 11 , wherein a surface roughness of the second face of the second insulating layer is larger than a surface roughness of the first face of the second insulating layer.  
     
     
         14 . A hybrid wiring board as set forth in  claim 11 , wherein a difference between a coefficient of expansion of the first insulating layer and a coefficient of expansion of the third insulating layer is larger than a difference between a coefficient of expansion of the second insulating layer and the coefficient of expansion of the third insulating layer.  
     
     
         15 . A hybrid wiring board as set forth in  claim 11 , the second insulating layer having a relative dielectric constant which is smaller than a relative dielectric constant of the first insulating layer and a relative dielectric constant of the third insulating layer.  
     
     
         16 . A hybrid wiring board as set forth in  claim 11 , wherein the first insulating layer comprises at least one polymer selected from the group consisting of polyimide type resin, bismaleimide type polyimide resin, polyphenylene ether type resin, and glass epoxy type resin.  
     
     
         17 . A hybrid wiring board as set forth in  claim 11 , wherein the second insulating layer comprises at least one polymer selected from the group consisting of polyimide type resin, polyester type resin, and polytetrafluoroethylene type resin.  
     
     
         18 . A hybrid wiring board as set forth in  claim 11 , wherein the third insulating layer comprises epoxy denatured polyimide type resin.  
     
     
         19 . A hybrid wiring board comprising: 
 a first board which is flexible, the first board having a first face and a second face, and the first face having a first region and a second region;    a first wiring layer formed on the first face of the first board;    an insulating resin layer formed on the first region of the first board, the insulating resin layer having a first face and a second face, the first face is opposed to the first region of the first board, and the insulating resin layer is rigid;    a second wiring layer having a second via land formed on the second face of the insulating resin layer, the second via land is opposed to the first via land, and the second wiring layer formed convex to the insulating resin layer; and    a conductive pillar pierced through the insulating resin layer so as to connect the first wiring layer and the second wiring layer.    
     
     
         20 . A hybrid wiring board as set forth in  claim 19 , wherein the first wiring layer having a first via land, the second wiring layer having a second via land, and the conductive pillar pierced through the insulating resin layer so as to connect the first via land and the second via land.  
     
     
         21 . A semiconductor device, comprising: 
 a first wiring substrate having a first face and a second face, the first wiring substrate having a first wiring layer which has a first via land formed on the first face of the first wiring substrate, and the first wiring substrate is rigid;    a second wiring substrate having a first face and a second face, the second wiring substrate having a second wiring layer which has a second via land formed on the second face of the second wiring substrate, and the second wiring substrate is flexible;    at least a semiconductor chip mounted on the first face of the second wiring substrate;    an insulating resin layer interposed between the first face of the first wiring substrate and the second face of the second wiring substrate; and    at least a conductive pillar pierced through the insulating resin layer so as to connect the first via land and the second via land.    
     
     
         22 . A semiconductor device as set forth in  claim 21 , wherein a wettability of the second face of the second wiring substrate is larger than a wettability of the first face of the second wiring substrate.  
     
     
         23 . A semiconductor device as set forth in  claim 21 , wherein the semiconductor chip is mounted on the second wiring substrate by face down bonding.  
     
     
         24 . A semiconductor device as set forth in  claim 19 , wherein the first wiring substrate comprises a rigid multi-layered wiring substrate having a plurality of wiring layer and at least an insulating layer.  
     
     
         25 . A semiconductor device as set forth in  claim 22 , wherein the wiring layers of the first substrate are interconnected by the conductive pillars piercing thorough the insulating layer of the first substrate.  
     
     
         26 . A semiconductor device as set forth in  claim 19 , wherein the second wiring substrate comprises a flexible multi-layered wiring substrate having a plurality of wiring layer and at least an insulating layer.  
     
     
         27 . A semiconductor device as set forth in  claim 21 , further comprises external connecting terminals formed on the second face of the first wiring substrate, and the external connecting terminals are connected with the semiconductor chip.  
     
     
         28 . A flexible wiring substrate, comprising: 
 a insulating film having a first face and a second face, and the insulating film is flexible;    a first wiring layer formed on the first face of the insulating film; and    a second wiring layer formed on the second face of the insulating film;    wherein a surface free energy of the insulating film of the first face is smaller than a surface free energy of the insulating film of the second face.    
     
     
         29 . A flexible wiring substrate as set forth in  claim 28 , wherein the insulating film having a reformed zone exposed to the second face.  
     
     
         30 . A flexible wiring substrate as set forth in  claim 28 , wherein a contact angle θ of a water drop and the second face of the insulating film is larger than 60 degree.  
     
     
         31 . A fabrication method of a hybrid wiring board, comprising the steps of: 
 (a) disposing a conductive pillar on a first via land disposed on a first surface of a first substrate, the first via land protruding on the first surface of the first substrate;    (b) disposing the first substrate and a second substrate that is a flexible substrate and that has a second via land protruding on a second surface of the second substrate so that the first via land faces the second via land through an insulation resin that is in a semi-cure state; and    (c) pressing the first substrate and the second substrate so as to plastic-deform a head portion of the conductive pillar and bond the conductive pillar and the second via land.    
     
     
         32 . The fabrication method as set forth in  claim 31 , further comprising the step of: 
 (d) reforming the second surface of the second substrate so as to improve the bonding strength between the second surface of the second substrate and the first surface of the first substrate, wherein the step (d) is followed by the step (b).    
     
     
         33 . The fabrication method as set forth in  claim 32 , wherein the step (d) is performed by washing the second surface of the second substrate by an alkali solution.  
     
     
         34 . The fabrication method as set forth in  claim 32 , wherein the step (d) is performed by plasma-ashing the second surface of the second substrate.  
     
     
         35 . The fabrication method as set forth in  claim 31 , wherein the first insulation layer is made of at least one polymer selected from the group consisting of polyimide type resin, bismaleimide type polyimide resin, polyphenylene ether type resin, and glass epoxy type resin.  
     
     
         36 . The fabrication method as set forth in  claim 31 , wherein the second insulation layer is made of at least one polymer selected from the group consisting of polyimide type resin, polyester type resin, and polytetrafluoroethylene type resin.  
     
     
         37 . The fabrication method as set forth in  claim 31 , wherein the third insulation layer is made of epoxy denatured polyimide type resin.  
     
     
         38 . A fabrication method of a hybrid wiring board, comprising the steps of: 
 (a) disposing a conductive pillar that is in an almost conical shape on a first via land of a first surface of a first substrate that is a rigid substrate;    (b) disposing the first substrate and a second substrate that is a flexible substrate and that has a second via land on a second surface of the second substrate so that the first via land faces the second via land through an insulation resin layer that is in a semi-cure state; and    (c) pressing the first substrate and the second substrate so as to plastic-deform a head portion of the conductive pillar and bond the conductive pillar and the second via land.    
     
     
         39 . A fabrication method of a hybrid wiring board, comprising the steps of: 
 (a) disposing a conductive pillar that is in an almost conical shape to a first via land of a first surface of a first substrate that is a rigid substrate;    (b) disposing an insulation resin layer that is in a semi-cure state on the first surface of the first substrate so that the conductive pillar is pierced through the insulation resin layer and a head portion of the conductive pillar is exposed;    (c) pressing the exposed head portion of the conductive pillar in the axial direction of the conductive pillar so as to plastic-deform the conductive pillar;    (d) disposing the first substrate and a second substrate that is a flexible substrate and that has a second via land on a second surface of the second substrate so that the head portion of the conductive pillar faces the second via land; and    (e) pressing the first substrate and the second substrate so as to plastic-deform the head portion of the conductive pillar and bond the conductive pillar and the second via land.    
     
     
         40 . A fabrication method of a hybrid wiring board, comprising the steps of: 
 (a) disposing a first conductive pillar that is in an almost conical shape on a first via land of a first surface of a first substrate;    (b) disposing a second conductive pillar that is in an almost conical shape on a second via land of a second surface of a second substrate that is a flexible substrate;    (c) disposing the first surface of the first substrate and the second surface of the second substrate so that the first via land faces the second via land through an insulation resin layer that is in a semi-cure state; and    (d) pressing the first substrate and the second substrate so as to plastic-deform and connect the first conductive pillar and the second conductive pillar.