Patent ID: 11953538
Assignee: WUHAN UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 4:
5. The method according to claim 4, wherein step S4 further comprises:
S4.2: screening IGBT circuits that fail due to the solder layer, establishing a lifetime prediction model of the solder layer according to temperature conditions and numbers of cycles through, N
    1
   
   =
   
    
     
      A
      ⁢
      Δ
      ⁢
      T
     
     j
     α
    
    ⁢
    
     e
     
      
       E
       a
      
      
       
        k
        B
       
       (
       
        
         T
         jm
        
        +
        
         2
         ⁢
         7
         ⁢
         3
        
       
       )
      
     
    
   
  
  ,, predicting and obtaining, by the lifetime prediction model of the solder layer, the lifetime N1 of the solder layer, wherein A and a are constants to be fitted, Ea is activation energy, and kB is a Boltzmann constant; and
S4.3: screening IGBT circuits that fail due to the bonding wire, establishing a lifetime prediction model of the bonding wire according to the temperature conditions and the numbers of cycles through, N
    2
   
   =
   
    
     
      A
      ⁢
      Δ
      ⁢
      T
     
     j
     α
    
    ⁢
    
     e
     
      
       E
       a
      
      
       
        k
        B
       
       (
       
        
         T
         jm
        
        +
        
         2
         ⁢
         7
         ⁢
         3
        
       
       )
      
     
    
   
  
  ,, predicting and obtaining, by the lifetime prediction model of the bonding wire, the lifetime N2 of the bonding wire.