Package having dummy package substrate and method of fabricating the same

Abstract

A package may include a stack of unit chip packages, and each unit chip package may include a printed circuit board. The printed circuit board may support a semiconductor chip and a connection terminal for connecting to an adjacent unit chip package within the stack. A dummy package substrate may be disposed on the semiconductor chip of the uppermost unit chip package for protecting the semiconductor chip of the uppermost unit chip package. A method of fabricating a package may involve stacking unit chip packages so that the printed circuit board of a lower unit chip package abuts against a solder bump of an upper unit chip package, and stacking a dummy package substrate on the printed circuit board of an uppermost unit chip package.

1 . A package comprising: 
 a plurality of unit chip packages, each unit chip package having a printed circuit board with one side supporting a semiconductor chip and another side supporting a connection terminal;    wherein the plurality of unit chip packages are stacked so that the printed circuit board of a lower unit chip package is connected to the connection terminal of an upper unit chip package; and    a dummy package substrate disposed on the printed circuit board of an uppermost unit chip package of the plurality of unit chip packages.    
     
     
         2 . The package of  claim 1 , wherein the dummy package substrate is bonded to the printed circuit board of the uppermost unit chip package via a solder bump.  
     
     
         3 . The package of  claim 2 , wherein the dummy package substrate is a dummy printed circuit board.  
     
     
         4 . The package of  claim 3 , wherein a photo solder resist layer is provided on the dummy printed circuit board, and wherein the photo solder resist layer exposes a land pattern to which the solder bump is bonded.  
     
     
         5 . The package of  claim 3 , wherein a copper pattern is provided on the dummy printed circuit board to facilitate heat discharge.  
     
     
         6 . The package of  claim 5 , wherein the copper pattern is a meshed pattern.  
     
     
         7 . The package of  claim 3 , wherein a copper interconnect pattern is provided on the dummy printed circuit board, and the copper interconnect pattern is covered with a photo solder resist layer.  
     
     
         8 . The package of  claim 3 , wherein a copper foil is provided on the dummy printed circuit board, and the copper foil is covered with a nickel-plating layer.  
     
     
         9 . The package of  claim 2 , wherein the dummy package substrate is a tape.  
     
     
         10 . The package of  claim 9 , wherein the tape is fabricated from polyimide.  
     
     
         11 . The package of  claim 1 , wherein the connection terminal is a solder bump.  
     
     
         12 . The package of  claim 1 , wherein each unit chip package includes a wire that interconnects the semiconductor chip to the printed circuit board, and wherein the wire penetrates through an inner hole of the printed circuit board.  
     
     
         13 . The package of  claim 12 , wherein the wire is covered with an encapsulation layer.  
     
     
         14 . The package of  claim 13 , wherein the encapsulation layer is an adhesive hardening layer.  
     
     
         15 . A method comprising: 
 providing a plurality of unit chip packages, each unit chip package having a printed circuit board with one side supporting a semiconductor chip and another side supporting a solder bump;    stacking the unit chip packages so that the printed circuit board of a lower unit chip package abuts against the solder bump of an upper unit chip package; and    stacking a dummy package substrate on the printed circuit board of an uppermost unit chip package.    
     
     
         16 . The method of  claim 15 , wherein the stacking of the dummy package substrate comprises bonding the dummy package substrate to the uppermost unit chip package using a solder bump.  
     
     
         17 . The method of  claim 16 , wherein the stacking of the dummy package substrate comprises: 
 bonding the solder bump to the dummy package substrate;    soaking the dummy package substrate bonded with the solder bump in a flux;    positioning the dummy package substrate on the uppermost unit chip package so that the solder bump of the dummy package substrate abuts against the printed circuit board of the uppermost unit chip package; and    performing a thermal treatment for bonding the solder bump of the dummy package substrate to the printed circuit board of the uppermost unit chip package and, simultaneously, bonding the solder bumps of the stacked unit chip packages to the printed circuit boards.    
     
     
         18 . The method of  claim 17 , wherein thermal treatment is performed at a temperature ranging from 200 to 250° C. so as to reflow the solder bumps of the dummy package substrate and of the printed circuit boards.  
     
     
         19 . The method of  claim 15 , wherein the stacking of the unit chip packages comprises: 
 soaking the solder bump of the upper unit chip package in a flux; and    mounting the upper unit chip package onto the lower unit chip package to connect the solder bump of the upper unit chip package to the printed circuit board of the lower unit chip package.    
     
     
         20 . The method of  claim 16 , wherein the dummy package substrate is a dummy printed circuit board.  
     
     
         21 . The method of  claim 20 , wherein a photo solder resist layer is provided on the dummy printed circuit board, and 
 wherein the photo solder resist layer exposes a land pattern to which the solder bump is bonded.    
     
     
         23 . The method of claim  22 , wherein the copper pattern is a meshed pattern.  
     
     
         24 . The method of  claim 20 , wherein a copper interconnect pattern is provided on the dummy printed circuit board, and the copper interconnect pattern is covered with a photo soldier resist layer.  
     
     
         25 . The method of  claim 20 , wherein a copper foil is provided on the dummy printed circuit board, and the copper foil is covered with a nickel-plating layer.  
     
     
         26 . The method of  claim 16 , wherein the dummy package substrate is a tape.  
     
     
         27 . The method of  claim 26 , wherein the tape is fabricated from polyimide.  
     
     
         28 . A package manufactured in accordance with the method of  claim 15.