Hi,
I was wanting to re-shoot some chips I had shot years back and am finding that some of them have this crackle appearance.
Is this "normal" - e.g. that just happens, or is there some better way to store these things to keep them from degrading? In most instances these are CPUs where you can pop / peel the lid off, so no chemicals were used to decap. Here is a representative example. This has been exposed to air for 5 years or so.
Do chips degrade or oxidize over time?
Moderators: rjlittlefield, ChrisR, Chris S., Pau
-
- Posts: 200
- Joined: Sat Dec 06, 2014 6:46 am
- Location: Allentown, PA, USA, Earth, etc.
- Contact:
Re: Do chips degrade or oxidize over time?
Don't know the answer to your question, but have a few data points . . .
.. chips decades old can still function -- some not hermetically sealed
.. semiconductor wafers in my possession now decades old and continuously exposed to (West Coast, CA) air don't show that crackle-like degradation - they do show dirt and scratches from handling
.. some forms of air pollution are pretty corrosive (e.g. burning sulfur-bearing coal for power generation)
.. thermal cycling and fatigue of the surface might also be a cause?
.. chips decades old can still function -- some not hermetically sealed
.. semiconductor wafers in my possession now decades old and continuously exposed to (West Coast, CA) air don't show that crackle-like degradation - they do show dirt and scratches from handling
.. some forms of air pollution are pretty corrosive (e.g. burning sulfur-bearing coal for power generation)
.. thermal cycling and fatigue of the surface might also be a cause?
-
- Posts: 3432
- Joined: Sat Nov 20, 2010 10:40 am
- Location: Santa Clara, CA, USA
- Contact:
Re: Do chips degrade or oxidize over time?
Those look like metallic crystal boundaries that would have been visible before. Only other possibility is the passivation coating has cracked, but most passivations don't usually crack like that.
-
- Posts: 200
- Joined: Sat Dec 06, 2014 6:46 am
- Location: Allentown, PA, USA, Earth, etc.
- Contact:
Re: Do chips degrade or oxidize over time?
With some psychedelic enhancements, it seems to impact the whole surface. Not just the traces. Weird. Perhaps it is a polyamid. I guess I could try dissolving some off with the ice melt cocktail.ray_parkhurst wrote: ↑Tue Aug 31, 2021 11:28 amThose look like metallic crystal boundaries that would have been visible before. Only other possibility is the passivation coating has cracked, but most passivations don't usually crack like that.
-- Bob