Laser dicing apparatus for a gallium arsenide wafer and method thereof

Abstract

The present invention discloses a laser dicing apparatus for a gallium arsenide wafer and a method thereof, wherein firstly, a gallium arsenide wafer is stuck onto a holding film; next, the gallium arsenide wafer together with the holding film is disposed on a working table; the gallium arsenide wafer has multiple chips or dice with a scribed line drawn between every two chips; a control device and an object lens are used to position the working table and a laser, and two video devices are used to observe whether the laser has been precisely aimed at one of the scribed lines; after parameters have been input into the control device, the laser is used to cut the gallium arsenide wafer, and the gallium arsenide wafer is then separated into multiple discrete chips or dice. The present invention can precisely cut gallium arsenide wafers, reduce the cost and accelerate the fabrication process.

1 . A laser dicing method for a gallium arsenide wafer, comprising the following steps: providing a gallium arsenide wafer, which has multiple chips or dice with a scribed line drawn between every two chips; disposing said gallium arsenide wafer on a working table; positioning a laser and said working table to enable said laser to be precisely aimed at one said scribed line on said gallium arsenide wafer, which is to be cut; inputting into a control device the length of one said scribed line to be cut and the spacing between one said scribed line to be cut and another said scribed line to be cut next; sequentially cutting said scribed lines to separate said gallium arsenide wafer into multiple discrete said chips.  
     
     
         2 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein said gallium arsenide wafer is stuck onto a holding film beforehand, and then, said gallium arsenide wafer together with said holding film is disposed on said working table.  
     
     
         3 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein said gallium arsenide wafer is disposed on said working table under a vacuum environment.  
     
     
         4 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein said working table utilizes a vacuum device to fix said gallium arsenide wafer.  
     
     
         5 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein said control device is used to adjust the X and Y coordinates of said laser and said working table in order to enable said laser to be precisely aimed at one said scribed line on said gallium arsenide wafer, which is to be cut.  
     
     
         6 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein a focal-length-adjust element is used to adjust the Z coordinates of said laser and said working table in order to adjust the focal length by which said laser is to be aimed at said scribed lines.  
     
     
         7 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein during said step of “positioning a laser and said working table to enable said laser to be precisely aimed at one said scribed line”, at least one video device is used to observe whether said laser has been precisely aimed at said scribed line.  
     
     
         8 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein said laser cuts said scribed lines into a depth larger than one tenth of the thickness of said gallium arsenide wafer.  
     
     
         9 . The laser dicing method for a gallium arsenide wafer according to  claim 8 , wherein during said step of “sequentially cutting said scribed lines”, a waste gas discharge device is used to discharge the dust and the waste gas generated by said cutting.  
     
     
         10 . The laser dicing method for a gallium arsenide wafer according to  claim 1 , wherein once said step of “sequentially cutting said scribed lines” is completed, said laser stops operating automatically.  
     
     
         11 . The laser dicing method for a gallium arsenide wafer according to  claim 10 , wherein after said step of “said laser stops operating automatically”, a vacuum device of said working table is shut, and said gallium arsenide wafer, which has been cut well, is taken out.