Non-Chemical Au bonding wires

[Woodworker1997]

Hi forum.

Has anybody had success quickly removing and collecting bonding wires such as the exposed ones on CCD's or other exposed dies?
I was thinking that maybe one of those "as seen on tv" lint rollers that are sticky until wet might work to collect the wires. Any thoughts?

Derek.

 

[bswartzwelder]

This has been covered on the forum many times. Use the search function.

Many people have had success with the gold wires inside of the chips. A lint roller is definitely NOT the way to go. The wires are smaller than a human hair and very short. A lint roller will not get the entire length of the wire. YOU WILL LOSE VALUES if you try this. Also, you will then be stuck with a lint roller covered with tiny wires and other stuff. How do you get the gold from the roller? You don't say how many chips you have, but it will take quite a few before the amount of gold recovered would even be measurable.

I believe some people have used chemical means to dissolve the chips, but the most popular method is to pyrolyze the chips then incinerate them. Pyrolyzing them is a process whereby you roast the chips WITHOUT oxygen. The chips will emit a lot of highly toxic fumes which should be either run through a scrubber or run through some form of afterburner. This will render the fumes almost harmless. Then you need to incinerate them. This involves reheating them in the presence of oxygen until they become a grayish/white ash. From there is is a relatively simple process to treat the ashes with chemicals to recover the gold. ALL of this needs to be done under a fume hood or outdoors. I cannot stress the importance of safety enough when doing this.

Please forgive any misspelled words. I am using a keyboard which I am not familiar with and am "fat fingering" the keys. I will look it over before posting it, but I may miss a word or two.

 

[Woodworker1997]

Thanks for the reply.

I'm not talking about black chips.
Some CCD focal planes have visible gold wire bonds you can get to without fire or crushing. I was thinking of using a small piece of the sticky when dry lint roller to strategically remove manually loosened bonding wires.

Derek

 

[Geo]

getting to them with acids is already pretty labor intensive. the amount of gold per chip is so small is so small, you would soon burn your self out. i have my own saying about such things "its like skinning a bee for his wax".

 

[Woodworker1997]

Geo,
your saying maybe my new favorite.

Derek.

 

[PlainsScrapper]

You could try using a small screwdriver or box cutters to remove them, just slide the blade or screwdriver across the contact pads to remove them, then repeat on the die itself. Then, tap it into a container for later processing, possibly with AR, but I am not too sure. Hope it helps.

 

[goldsilverpro]

Once you collect from 2 to 4 miles (depending on the diameter) of the gold wires, you'll have an ounce.