Wafer Scratches

Problem description:

Process equipment scratches the back side of the wafers.  Vast engineering efforts were made without finding the root cause.

InnerSense Solution:

Using SmartWafer  a Wafer Handling Analyzer the customer found that the equipment robot arm touches the wafer every time it goes in. The upper chart shows a peak each time that the arm touches the wafer. The lower chart shows normal behaviour of a robot arm. Finding the root cuase of the wafer breakage caused the customer to adopt the methodology of High Precision Maintenance (HPM)                                                         

Bad Test results

 Robot  arm touches wafer

Good Test results (Finger Print)