Analisys of 3 chips with I(Vdda) syndrome

1
Analisys of 3 chips with I(Vdda) syndrome
3 chips suffering the I(Vdda) syndrome have been
stripped from 2 AMS modules and have been
observed with the thermocamera, under microscope
and under micro x-ray. The informations gathered
are compared with the bare module probing
previously done in Milano.
G. Gariano,C. Gemme, P. Netchaeva, L. Rossi, A.
Rovani, F. Vernocchi INFN- Genova
2
Module 20210210142301, chip 6 thermographic
image from Inframetrics 760
Raw 56
Colum 9,10
Hot spot localized and 5C above normal
3
Module 20210210142301, chip 6 microscope images
Hard metal, not Indium, deeply connected to chip
surface. Impossible to take it off with W-needles.
Raw 56
Colum 9,10
4
Module 20210210142301, chip 6 x-ray images
Nothing visible where I did operate with
W-needles
5
Module 20210210142301, chip 6, scan with all
column pairs enabled
Digital inj
Analog inj (both int. and ext.)
6
Module 20210220011701, chip F thermographic image
Hot spot localized and 10C above normal
Col 17
7
Module 20210220011701, chip F, microscope image
Col 17
Hard metal, not Indium, deeply connected to chip
surface. Impossible to take it off with W-needles.
8
Module 20210220011701, chip F x-ray image
Nothing visible in insert
9
Module 20210220011701, chip F, scan with all
column pairs enabled
Digital inj
Analog inj (both int. and ext.)
10
Module 20210210142301, chip 8 thermographic image
Hot spot localized and 10C above normal and hot
column bus
Raw 73
Col 9,10
11
Module 20210210142301, chip 8 microscope image
Raw 73
Hard metal, not Indium, deeply connected to chip
surface. Impossible to take it off with W-needles.
Col 9,10
12
Module 20210210142301, chip 8 x-ray image
Nothing visible in raw 72
13
Module 20210210142301, chip 8, scan with all
column pairs enabled
Digital inj
Analog inj (both int. and ext.)
14
Tentative conclusions

• In all 3 cases we observe
• a hot spot in correspondence of where the
  electronics problem appears
• a deposit of hard material (debris from
  cutting?) in correspondence with the hot spot
• the hard material has low-Z (like silicon) as it
  is invisible at x-ray imaging
• It would be interesting to have comments from
  electronics and module experts.
• We probably have be more careful in the cleaning
  process debris can more easily be trapped by the
  (sticky?) In bumps.