Apparently, fast annealing at high temperature (400 degrees C) is detrimental to the wafer quality (wafer 80).

Four 6 in. wafers have been annealed at 150 degrees C for 2 weeks (one wafer at LBNL and three at Honeywell). The following is the combined summary of changes in die classification for these wafers:

good -> fair :  0 die
good -> bad :  5
fair -> good :  3
fair -> bad :    5
bad -> good :  3
bad -> fair :    4
No change :    522

The changes in the classification do not seem to be directly related to the problem of bad vias. For example, from 5 chips which went from good to bad, 2 failed analog logic tests (bad cell IDs), 2 got several bad channels, and 1 exhibited too large DVDD curent.

Annealing at 150 degrees C for 2 weeks didn't change anything on the 4 in. wafer used as a control (wafer 148).