Patent ID: 11876005
Assignee: ACM RESEARCH (SHANGHAI) INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for cleaning flip chip assemblies comprising:
loading at least one flip chip to one or more flip chip carriers held by a chuck assembly at the periphery of the chuck assembly, wherein the chuck assembly comprises a recess located in the center of the chuck assembly and one or more guide channels connecting the recess with the one or more flip chip carriers;
wherein the at least one flip chip is oriented in a horizontal configuration on the chuck assembly;
performing a cleaning process to clean the at least one flip chip, the cleaning process comprising:
supplying a cleaning solution for removing contaminants onto the recess while rotating the chuck assembly at a low rotation speed, wherein the cleaning solution spins into the one or more flip chips through the one or more guide channels due to centrifugal forces and is held in the one or more flip chips without being scattered outward under dominance of surface tension, wherein the cleaning solution has a liquid density p and a surface tension coefficient σ;
continuously supplying the cleaning solution while rotating the chuck assembly at a high rotation speed wherein a centrifugal force overcomes the surface tension and allows the cleaning solution and contaminants trapped therein to be dragged out; and
repeating the cycling of rotating the chuck assembly at the low rotation speed and rotating the chuck assembly at the high rotation speed at least once;
wherein the low rotation speed and high rotation speed is determined based upon a length B of the at least one flip chip, a width A of the at least one flip chip, a radius r of position of the one or more flip chip carriers on the chuck assembly, a space h between two chip bond pads of the at least one flip chip, a chuck spin time t during the rotating step, the liquid density of the cleaning solution, and the liquid surface tension coefficient of the cleaning solution;
said low rotation speed Nl is in a range less than, 60
    ×
    
     
      (
      
       
        
         2
         ⁢
         σ
        
        
         ρ
         ⁢
         hAr
        
       
       +
       
        
         2
         ⁢
         B
        
        
         rt
         2
        
       
      
      )
     
     
      1
      2
     
    
   
   
    2
    ⁢
    π
   
  
  ;
 

said high rotation speed Nh is in a range higher than, 60
    ×
    
     
      (
      
       
        
         2
         ⁢
         σ
        
        
         ρ
         ⁢
         hAr
        
       
       +
       
        
         2
         ⁢
         B
        
        
         rt
         2
        
       
      
      )
     
     
      1
      2
     
    
   
   
    2
    ⁢
    π
   
  
  .