According to the actual process spec, there needs to be pad oxide and
a layer of nitride as CMP end stop below the thick LTO.

Updated the graphics accordingly

Added wet station J cleaning step after semi-clean CMP step
according to Michael

According to Michael, the wafers need to be put into RCA after CMPing
in wetstation B3

According to the input from some fellow process engineers
I've now removed the serious issue of irreversible crystal damage
during CMPing without nitride CMP end stop