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FiP

FiP

Active member
Joined
Jun 15, 2015
Messages
37
Hello to all,

I've been prepping an ATI graphics card for sorting.
After i exposed what looked like a chip under the heatsink, i made the following finding: under the cap is a board. This board has some gold plating exposed. However under the solder mask is a nice layer of gold plating which makes it nice a candidate for a solder removing bath (elsewhere on the forum).
I don't have many of these so it'll be hard to give yield results.

If some of you bothered dismanteling these i have a question:

Under the cap was a foil of silvery shiny metal. The amount is such that it's tiny to be tested. Has any of you knowledge of what it is? Al, Pt, Pd?

My bests to all
 
Hello Patnor, thanks for the interest.
Here is the picture:
In A the cap
In C the board it's attached to
And in E the resin it was alla sandwiched in.
The metal i'm asking about is the shiny one in B, it was attached to the board where there is still a bit stuck to it in D.
It could be Al but it could be something else so if anyone knows, thanks for helping!

My best to all!
 

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I think that is the heat sink interface material. Usually a paste, but with a lamented chip could be a foil of some type. Doubt it would be a PM.
 
The bright silvery bits come from the shattered IC silica glass wafer, the glass has been doped with metals that merely look to have value.

Will do no harm to allow all of it to follow through to Aqua Regia recovery.
 
That is a ball grid array with an integral heat spreader (the metal cap) in the resin. The board looks nice, but the real gem is hidden under the heat spreader. All connections to the chip is made with bond wires of pure gold. A kilo of mixed BGA chips will give you about 5g gold and almost all of that is in the black resin. That includes the two pieces marked E.

First I get rid of the green board, then I incinerate, crush, pan, clean with nitric acid, dissolve, precipitate and melt. Done right it will get you a nice button.

Göran
 
sokon said:
In the green bottom part of BGA chips is 0.7g Au / kg (Umicore analysis)
Click to expand...

Now this is a nice piece of information. I think I will have a look on these the next weeks. Thanks
 
Hello to all!

Thanks for all this input!
I indeed saved all the resin for future incinerating and the green bottom is to be stripped from solder mask for getting the gold plating.

Judging by what could be a heat conductive material and by your comments i though of adding the glassy shiny bit to a MMC pot for Pd Pt Ag processing. Does anyone think it would ruin the reactions or could be worth a try? Or just to the trash can?

Thank you to all

My best to all
 
I believe the the metal inside the chip is aluminum but it has something else in very tiny quantities I can't remember the name of.
 
Judging by what could be a heat conductive material and by your comments i though of adding the glassy shiny bit to a MMC pot for Pd Pt Ag processing. Does anyone think it would ruin the reactions or could be worth a try? Or just to the trash can?

"A" at the picture is nickle plated copper or aluminium, there is no reason to use a expensive material in the heat spreader.
The solder under the green part is possibility Sn and silver, and in the black resin is the gold. No palladium or platin in a BGA.

Solar, how will you process the green part? My guess is the solder is the best part of the green bottom. Patnor have sold a lot of this material very cheap i remember.
Henrik
 
The green base "C" in the picture above, has gold plating on all connection points and the square silver looking spot in the center contains, silver.
 
canedane said:
Judging by what could be a heat conductive material and by your comments i though of adding the glassy shiny bit to a MMC pot for Pd Pt Ag processing. Does anyone think it would ruin the reactions or could be worth a try? Or just to the trash can?

"A" at the picture is nickle plated copper or aluminium, there is no reason to use a expensive material in the heat spreader.
The solder under the green part is possibility Sn and silver, and in the black resin is the gold. No palladium or platin in a BGA.

Solar, how will you process the green part? My guess is the solder is the best part of the green bottom. Patnor have sold a lot of this material very cheap i remember.
Henrik
Click to expand...

Hello,

You are right indeed, the cap in A is Al, no point in processing this (by the way once you take the heatsink off it is coverding in a white conductive paste).
To process the green board, i'd' suggest hot NaOH.
 
Geo said:
The green base "C" in the picture above, has gold plating on all connection points and the square silver looking spot in the center contains, silver.
Click to expand...

Thank you Geo for this bit of information.
Do you think the stuff in B that was sitting above the silver plating on the base in D would hold any PMs?
 
"B" is the actual silicon die (chip) and contains no PM value. The bonding wires attach to the sides of the chip along the thin edge. When you do process a batch, you will find that the silicon die and the resin is much harder to separate in bulk. Separating the bonding wires from the chips is the real trick.
 
canedane said:
Judging by what could be a heat conductive material and by your comments i though of adding the glassy shiny bit to a MMC pot for Pd Pt Ag processing. Does anyone think it would ruin the reactions or could be worth a try? Or just to the trash can?

"A" at the picture is nickle plated copper or aluminium, there is no reason to use a expensive material in the heat spreader.
The solder under the green part is possibility Sn and silver, and in the black resin is the gold. No palladium or platin in a BGA.

Solar, how will you process the green part? My guess is the solder is the best part of the green bottom. Patnor have sold a lot of this material very cheap i remember.
Henrik
Click to expand...

I have scraped off most of the solder. I will clean the green parts with HCl, solid powders to stock pot, then I would process the green parts together with other AP stuff. Not tried yet, but I can't see any problems.

I think it is best to collect the solder as is, melted and when enough, sold to a refiner that pays both for tin and pm's.
 
There is XRF analysis of that solder balls in my big thread.
2% Ag and 0.22% Au quite bit of a lead and of course tin
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=11827&start=510#p211524
 
patnor1011 said:
There is XRF analysis of that solder balls in my big thread.
2% Ag and 0.22% Au quite bit of a lead and of course tin
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=11827&start=510#p211524
Click to expand...

Hello Patnor,

Thanks a million, that's spot on!
It makes sense they have a small amount of Ag (Even from what they sit on (Geo's post)).

That'll help me greatly for my sorting and processing.

All the best!

My thanks to all too for all the very useful posts.

My bests to all!
 
Hello to all,

I though you would like to see how it came out after hot NaOH bath.
It came really clean and unveiled gold plated tracks on both sides.
The small bit of solder ball that was stuck to it dissolved completely and fast.

Here are the pictures of both sides after hot NaOH. Hope it will help someone.

My bests to all!
 

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What you see there is gold plated copper wire. It will completely dissolve in nitric, amount of plating is negligible. That plating will not cover cost of NaOH not to mention cost of nitric. I see a lot of them when I process BGA, after incinerating, crushing and sieving they tend to accumulate in lumps however they are gone after Nitric cleaning of concentrate. Gold bonding wires are usually just about 1mm long. When they accumulate difference can be easily spotted.
 

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