Circuit film with bump, film package using the same, and related fabrication methods

Abstract

A circuit film having film bumps is provided for a film package. An IC chip is mechanically joined and electrically coupled to the circuit film through the film bumps instead of conventional chip bumps. In a fabrication method, a base film is partially etched by a laser to create an etched area that defines raised portion relatively raised from the etched area. Then a circuit pattern is selectively formed on the base film, partly running over the raised portions. The raised portion and the overlying circuit pattern constitute the film bumps having a height not greater than the height of the circuit film.

1 . A method of fabricating a circuit film, the method comprising: 
 etching a base film to create at least one raised portion; and    selectively forming a circuit pattern on the base film, the circuit pattern partly on the raised portion, wherein the raised portion and the circuit pattern constitute at least one film bump.    
     
     
         2 . The method of  claim 1 , wherein etching the base film is performed by a laser.  
     
     
         3 . The method of  claim 2 , wherein the laser removes the base film to a specific depth per one shot.  
     
     
         4 . The method of  claim 3 , wherein the laser is an eximer laser having energy of about 1000 mJ/cm2 and frequency of about 300 Hz.  
     
     
         5 . The method of  claim 1 , wherein selectively forming the circuit pattern includes forming a metal coating layer on the circuit pattern.  
     
     
         6 . The method of  claim 1 , wherein selectively forming the circuit pattern is performed by electroplating.  
     
     
         7 . The method of  claim 5 , wherein forming the metal coating layer is performed by electroless plating.  
     
     
         8 . A method of fabricating a film package, the method comprising: 
 fabricating a circuit film having film bumps, including partially etching a base film to create at least one raised portion raised from the etched area, and forming a circuit pattern on the base film, the circuit pattern partly on the raised portion, the raised portion and the overlying circuit pattern comprising the film bumps;    placing a sealing resin on the circuit film; and    attaching an integrated circuit (IC) chip to the circuit film such that input/output (I/O) pads of the IC chip are mechanically joined and electrically coupled to the film bumps.    
     
     
         9 . The method of  claim 8 , wherein partially etching the base film is performed by a laser.  
     
     
         10 . The method of  claim 8 , wherein selectively forming the circuit pattern includes forming a metal coating layer on the circuit pattern.  
     
     
         11 . The method of  claim 8 , wherein attaching the IC chip to the circuit film includes placing the I/O pads on the film bumps, and curing the sealing resin to support the I/O pads and the film bumps.  
     
     
         12 . The method of  claim 8 , wherein attaching the IC chip to the circuit film is performed by a number of conductive particles in the sealing resin.