System, apparatus and method of selective laser repair for metal bumps of semiconductor device stack

Abstract

Exemplary embodiments of the selective laser repair apparatus and method may allow the repair of metal bumps in a semiconductor device stack by applying a laser beam to a damaged and/or defective bump. Metal bumps may be repaired and individual chips and/or packages forming a device stack need not be separated. The operation of a control unit and a driving unit may position a laser unit such that a laser beam may be irradiated at the damaged and/or defective metal bump. An X-ray inspection unit may obtain information about the damaged and/or defective metal bump.

1 . An apparatus for selectively repairing metal bumps of a semiconductor device stack having a plurality of chips or packages connected by the metal bumps, the apparatus comprising: 
 a stage unit, on which the semiconductor device stack is loaded;    a laser unit adapted to generate a laser beam and selectively irradiate the laser beam at a metal bump of the semiconductor device stack;    a driving unit connected to the laser unit and adapted to supply a force to the laser unit; and    a control unit connected to the laser unit and the driving unit and adapted to control the laser unit and the driving unit,    wherein the laser unit is located at a position suitable for irradiating the laser beam at a metal bump, and wherein the laser beam is irradiated at the metal bump while the laser beam is focused on the metal bump.    
   
   
       2 . The apparatus of  claim 1 , wherein the laser unit includes a laser beam source adapted to generate the laser beam and an optical system adapted to control a path of the laser beam and convert the laser beam into a focused beam.  
   
   
       3 . The apparatus of  claim 2 , wherein the optical system includes at least one mirror reflecting the laser beam and regulating the path of the laser beam.  
   
   
       4 . The apparatus of  claim 2 , wherein the optical system includes at least one condensing lens converting the laser beam into the focused beam and reducing a spot diameter of the focused beam.  
   
   
       5 . The apparatus of  claim 2 , wherein the optical system includes a wavemeter receiving the laser beam and measuring the wavelength of the laser beam to determine the depth of a focus of the laser beam.  
   
   
       6 . The apparatus of  claim 4 , wherein the spot diameter of the focused beam is in the range of 20 μm to 150 μm.  
   
   
       7 . The apparatus of  claim 1 , further comprising an X-ray inspection unit connected to the control unit and adapted to send information about the metal bumps to the control unit.  
   
   
       8 . A method for selectively repairing metal bumps of a semiconductor device stack having a plurality of chips or packages connected by the metal bumps, the method comprising: 
 inspecting the semiconductor device stack;    identifying a damaged metal bump; and    repairing the damaged metal bump by selectively irradiating a laser beam at the damaged metal bump.    
   
   
       9 . The method of  claim 8 , wherein the inspecting of the semiconductor device stack includes, 
 applying X-rays to the device stack, and    detecting the diffraction angle of the X-rays;    obtaining information in connection with the damaged metal bump.    
   
   
       10 . The method of  claim 8 , wherein the laser beam is a carbon dioxide (CO 2 ) laser beam or a neodymium: yttrium aluminum garnet (Nd: YAG) laser beam.  
   
   
       11 . The method of  claim 8 , wherein the laser beam has near-infrared wavelengths.  
   
   
       12 . The method of  claim 8 , wherein the laser beam has a power in the range of 20 W to 70 W.  
   
   
       13 . The method of  claim 11 , wherein the wavelength of the laser beam is in the range of 0.7 μm to 1.2 μm.