Removing silicon die ceramic ic

[ssmontecarlo]

It truly amazes me how individuals process gold and other metals. I sit and read and read and read how people process PGM's. If it be computer scrap, karat gold, and even ore. By means of nitric acid. AP, sulfuric acid stripping cell, etc. It truly amazes me. Be safe.

 

[kurtak]

you aren't losing anything. There is no gold underneath the die - just bonding glue.

As pointed out by Goran that just is not true

but other than that, the die just get tossed with the trash at the end, stuck to the package or not.

So if you are not running your ceramic ICs in AR until the silicon die falls off the ceramic chip & throwing them in the trash before the silicon die is released from the ceramic you are most certainly throwing gold away

Though not all ceramic ICs have gold braze under the die the fact is that MANY of them do have the gold braze under the die

Example ; --------

Back in 2019 six of us got together over in England at Jons place for a week - while there I ran a batch of ceramic ICs - just a little over 2 kilos which recovered 52 or 56 grams gold (don't remember exactly)

When done running the batch not all of the dies had fully released from the ceramic bodies

So - Goran went through the ceramic bodies one at a time & picked out the ones that still had the dies stuck to the ceramic (guessing plus/minus about 1/3 still had die stuck to ceramic) --- he (Goran) took those back home to Sweden & re-ran them from which he recovered another couple/few grams gold from the gold braze under the dies still stuck to the ceramic

Here are pics of that batch of ceramic ICs & the boards they came from

Kurt

 

[anachronism]

A couple of points though Kurt. These were top of the line military "no expense spared" chips. They were also from an era prior to the commercial Wintel processors. And finally - I must be getting old because I don't remember Goran taking them home haha.

Edit- it was 52.8g.

 

[g_axelsson]

A couple of points though Kurt. These were top of the line military "no expense spared" chips. They were also from an era prior to the commercial Wintel processors. And finally - I must be getting old because I don't remember Goran taking them home haha.

Edit- it was 52.8g.

Just forget that I said something...

I still have a beaker with the gold, I'll bring it with me next time I visit. 1.5g out of 52g, about 3% loss of gold from behind the dies.



Göran