Method of fabricating a packaging substrate

Abstract

A method of fabricating a packaging substrate is provided, including: providing a carrier having two carrying portions, each of the carrying portions having a first side and a second side opposite to the first side and the carrying portions are bonded through the second sides thereof; forming a circuit layer on the first side of each of the carrying portions; and separating the two carrying portions from each other to form two packaging substrates. The carrying portions facilitate the thinning of the circuit layers and provide sufficient strength for the packaging substrates to undergo subsequent packaging processes. The carrying portions can be removed after the packaging processes to reduce the thickness of packages and thereby meet the miniaturization requirement.

1 . A method of fabricating a packaging substrate, comprising:
 providing a carrier having two carrying portions, each of the two carrying portions having a first side and a second side opposite to the first side, and the two carrying portions being bonded together through the second sides thereof, so that the two carrying portions are stacked on each other;   forming a single circuit layer on the first side of each of the two carrying portions; and   separating the two carrying portions from each other to form two packaging substrates.   
     
     
         2 . The method of  claim 1 , wherein an adhesive layer is formed between the second sides of the carrying portions. 
     
     
         3 . The method of  claim 2 , further comprising removing the adhesive layer to separate the carrying portions from each other. 
     
     
         4 . The method of  claim 2 , wherein the adhesive layer is formed in a non-circuit area positioned at edges of the second sides of the carrying portions. 
     
     
         5 . The method of  claim 4 , further comprising cutting along an inner side of the adhesive layer to separate the carrying portions from each other. 
     
     
         6 . The method of  claim 1 , further comprising disposing a strengthening member between the second sides of the carrying portions. 
     
     
         7 . The method of  claim 1 , further comprising forming a surface treatment layer on the circuit layers. 
     
     
         8 . The method of  claim 1 , wherein each of the carrying portions further has an insulating layer, a dielectric layer formed on the insulating layer, a metal carrying layer formed on the dielectric layer, and a metal layer formed on the metal carrying layer. 
     
     
         9 . The method of  claim 1 , wherein a metal layer is formed on the first side of each of the carrying portions and the step of forming the circuit layer further comprises:
 forming a resist layer on the metal layer and a plurality of openings in the resist layer for exposing a portion of the metal layer;   forming the circuit layer on the exposed portion of the metal layer; and   removing the resist layer.   
     
     
         10 . The method of  claim 1 , wherein a metal layer is formed on the first side of each of the carrying portions and the circuit layer is formed by etching the metal layer. 
     
     
         11 . The method of  claim 1 , wherein each of the carrying portions further has a first metal layer formed on the first side and a second metal layer formed on the second side, and the carrying portions are bonded through the second metal layers. 
     
     
         12 . The method of  claim 11 , wherein the first metal layer and the second metal layer are made of copper foil. 
     
     
         13 . The method of  claim 11 , wherein the second metal layers of the carrying portions are bonded by vacuum lamination. 
     
     
         14 . The method of  claim 11 , wherein the step of forming the circuit layer further comprises:
 forming a preliminary metal layer on the first metal layer;   forming a resist layer on the preliminary metal layer, and then forming a plurality of openings in the resist layer for exposing a portion of the preliminary metal layer;   removing the exposed portion of the preliminary metal layer; and   removing the resist layer.   
     
     
         15 . The method of  claim 14 , wherein the preliminary metal layer is laminated on the first metal layer. 
     
     
         16 . The method of  claim 1 , further comprising forming a solder mask on the first side of each of the carrying portions.