Semiconductor Photo Gallery

   

 

Cratering

         

Figure 1. Cratering - Silicon Damage Under the Bond Pad 

          

Figure 1 shows a SEM photo of cratering, or the failure mechanism wherein the silicon under the bond pad has been mechanically damaged.  Gross cases of cratering results in a chunk of the underlying silicon being chipped off and dislodged from its place, forming a 'hole' or 'crater' on the silicon substrate (hence the term 'cratering'). 

      

Cratering can be due to several causes, but the most common reason for cratering is over-bonding, or the situation wherein the bonding tool has transmitted excessive stresses to the bond pad during wirebonding. Cratering can result in lifted bonds, so an engineer analyzing a bond lifting issue must look at the bond pad closely during investigation to ensure that the appropriate corrective action will be taken.

  

See Also:  Wirebonding; Bonding Failures

      

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