Target debonded

Last week , a tool in our production line ran into problem , failing some parameters constantly.

So we decided to open the chamber and perform the inspection.

Found out the target (tantalum) had been debonded. From surface it looks like uneven surface. Looks like patch by patch over the target.

Back of the target hardly see any abnormaliy.

Possible root cause maybe the shaft area, further investigation still on-going though.