Wiring substrate and semiconductor device

Abstract

A wiring substrate 11 includes a wiring substrate main body 31 having a semiconductor element mounting area A, a wiring pattern 33 provided on an upper surface 31 A of the wiring substrate main body 31 at a portion corresponding to the semiconductor element mounting area A, a solder resist 35 provided on the upper surface 31 A of the wiring substrate main body 31 and having an opening portion 43 whose size is substantially equal to the semiconductor element mounting area A when viewed from a top, and a dam 37 provided on the solder resist 35 to block an underfill resin 13 provided in a clearance between the semiconductor element 12 and the wiring substrate main body 31. A distance between an inner wall of the opening portion 43 of the solder resist 35 and an inner wall of the dam 37 is partially varied.

1 . A wiring substrate, comprising:
 a wiring substrate main body having a semiconductor element mounting area in which a semiconductor element is mounted;   a wiring pattern provided on a first surface of the wiring substrate main body at a portion corresponding to the semiconductor element mounting area, and having connection portions to which the semiconductor element is flip-chip bonded;   a solder resist provided on the first surface of the wiring substrate main body, and having an opening portion whose size is substantially equal to the semiconductor element mounting area, when viewed from a top; and   a dam provided on an upper surface of the solder resist so as to surround the semiconductor element mounting area, for blocking an underfill resin provided in a clearance between the semiconductor element and the wiring substrate main body,   wherein a distance between an inner wall of the opening portion of the solder resist and an inner wall of the dam is partially varied.   
     
     
         2 . The wiring substrate according to  claim 1 , wherein
 an underfill resin feeding area, from which the underfill resin is fed, is defined at a portion of a clearance between the semiconductor element and the wiring substrate main body,   a first distance is defined between the inner wall of the opening portion of the solder resist and the inner wall of the dam in the underfill resin feeding area,   a second distance is defined between the inner wall of the opening portion of the solder resist and the inner wall of the dam in are area other than the underfill resin feeding area,   the first distance is larger than the second distance.   
     
     
         3 . The wiring substrate according to  claim 2 , wherein the second distance is decreased stepwisely or continuously. 
     
     
         4 . The wiring substrate according to  claim 1 , further comprising:
 a pad to which another wiring substrate is mounted and which is provided on the wiring substrate main body at a position outside the dam.   
     
     
         5 . The wiring substrate according to  claim 4 , further comprising:
 an external connection pad which is electrically connected to the wiring pattern and is provided on a second surface of the wiring substrate main body, wherein   the second surface is positioned on an opposite side to the first surface.   
     
     
         6 . A semiconductor device, comprising: a wiring substrate, comprising:
 a wiring substrate main body having a semiconductor element mounting area in which a semiconductor element is mounted;   a wiring pattern provided on a first surface of the wiring substrate main body at a portion corresponding to the semiconductor element mounting area, and having connection portions to which the semiconductor element is flip-chip bonded;   a solder resist provided on the first surface of the wiring substrate main body and having an opening portion whose size is substantially equal to the semiconductor element mounting area, when viewed from a top; and   a dam provided on an upper surface of the solder resist so as to surround the semiconductor element mounting area, for blocking an underfill resin provided in a clearance between the semiconductor element and the wiring substrate main body,   wherein a distance between an inner wall of the opening portion of the solder resist and an inner wall of the dam is partially varied;   
       the semiconductor element flip-chip bonded to the connection portions; and 
       the underfill resin provided in a clearance between the semiconductor element and the wiring substrate. 
     
     
         7 . The wiring substrate according to  claim 6 , wherein
 an underfill resin feeding area, from which the underfill resin is fed, is defined at a portion of a clearance between the semiconductor element and the wiring substrate main body,   a first distance is defined between the inner wall of the opening portion of the solder resist and the inner wall of the dam in the underfill resin feeding area,   a second distance is defined between the inner wall of the opening portion of the solder resist and the inner wall of the dam in are area other than the underfill resin feeding area,   the first distance is larger than the second distance.   
     
     
         8 . The wiring substrate according to  claim 7 , wherein the second distance is decreased stepwisely or continuously. 
     
     
         9 . The wiring substrate according to  claim 6 , further comprising:
 a pad to which another wiring substrate is mounted and which is provided on the wiring substrate main body at a position outside the dam.   
     
     
         10 . The wiring substrate according to  claim 9 , further comprising:
 an external connection pad which is electrically connected to the wiring pattern and is provided on a second surface of the wiring substrate main body, wherein   the second surface is positioned on an opposite side to the first surface.