DUT Wafer Probe Test Boards

[turtle]

I'm new to this group and have been scrapping for PMs as a hobby for about 4 years with minimal success. I came across this site three weeks ago and have been reading Hoke and this site ever since.

I have acquired some discarded wafer probe test boards. These boards are 5.5" by 6" of surface area BY 1/4" thick. They were covered with solder mask that I removed with Steve's method of using warm lye. By that way, that was a slick method, I added them to a crock pot and added enough solution to covert the boards. After 5 minutes the mask just slipped right off in a 5 gallon rinse pale of hot water. Under the solder mask these board are covered with gold. See photos.

1. Has anyone ever done recovery on these?
2. I wonder if the material is a gold foil or a plated surface?
3. How would you remove the gold?

Thanks,
Turtle

 

[Barren Realms 007]

Nice looking board.

Either put them in AP or use nitric.

I would snip off about a sq inch of the board and mixe a little bit of AP and see how long it takes to deplate.

The gold could come off as a sheet or in small flakes depending on how thick the plating is will determine how much it will break up.

 

[beachbum1975]

Turtle, curious - how many of these boards do you have? (Those are gorgeous! I'd love you try and remove the gold!)

 

[turtle]

Barren, thanks for the suggestion. I think I'll try a small sample batch in AP and let you all know how it goes.

I cut one and the cross section reveals a gold surface sandwiched in the center of the board too.

I wonder if a sulfur cell will work to deplate the top and bottom surface, might try that too.

Beachbum, I have about 30 or 40 of them. (locked up and I may or may not have a gun) - just kidding -


I'm also thinking about a wet process with acid to remove the surface mounted material - any suggestions or ideas for that? I tried a heat gun and that worked well but I want to find a batch process that I can just let a batch of them sit in for a while and not use much energy or personal time on.


Thanks,
Turtle

 

[Palladium]

Can you post a pic of the gold center that is sandwiched in the middle ?

 

[Barren Realms 007]

I don't think I would run them in a cell, too many small areas that might not deplate and you could still end up running it in AP to get the balance.

 

[turtle]

View attachment 1

 

[beachbum1975]

Beachbum, I have about 30 or 40 of them. (locked up and I may or may not have a gun) - just kidding -

Turtle, that's great (the number of boards, not the gun part )! My guess is they provide you with about 7 -10 grams after a quick look... Keep us posted!

Cheers,

beachbum1975

 

[turtle]

I started a batch of AP tonight with a small sample of these boards. This is my first AP batch. I found an AP outline on this forum based on Steve's teachings, I will follow it to a T and keep you all posted on my progress and results.

Turtle

 

[Barren Realms 007]

I started a batch of AP tonight with a small sample of these boards. This is my first AP batch. I found an AP outline on this forum based on Steve's teachings, I will follow it to a T and keep you all posted on my progress and results.

Turtle

Go easy on the peroxide so you don't disolve your gold.

 

[turtle]

over 24 hours and so far so good.

Stared with 5 boards, 2 liters HCL, 1 liter H2O2 (3%) and placed boards in strainer bucket inside larger bucket filled with AP solution.

observed solution reacting on boards as heat was given off and bubbles formed.

stirred several times over ~ 12 hour period.

observed foil floating in black colored solution and stirred/agitated again.

observed after ~ 4 additional hours and solution color had not changed and reaction seemed to have slowed or stopped.

added 300ml of H2O2, stirred/agitated and observed same reaction again.

~ 10 hours later observed that solution had slowed again, however more foil floating in black solution with more of the base of the boards being exposed.

scrubbed the board surface and swirled in black solution to release as much foil as possible.

still more stubborn foil on boards.

added 200ml of H2O2 and agitated mix.

killed a $hit load of dam mosquitoes.

took some photos to post with update.






Some a doing better





Sample of the solution



Just concerned that I may be overdoing the H2O2 - What do you all think?

Thanks,
Turtle

 

[Barren Realms 007]

Looks like you are on the right track, I see a couple of small sheets of gold in that 2nd picture. You should be ok on the amount of peroxide you are adding. I try to add enough for a color change back to green if the solution is not to saturated with copper, comes with playing around and learning. Let the saturated solution stand for a day or two after you finish and if you dissolved any of your gold it will settle to the bottom as small black specks. Siphon your solution off when you get finished and then you will be ready for your next step.

 

[lazersteve]

Adding an air bubbler will keep your solution active longer. You can avoid dissolving any gold by doing this and adding only HCl when things darken or you see white/gray/off-white powder (copper I chloride).

Have you read the Copper Chloride document on my website?

Steve

 

[turtle]

Thanks Steve.

I have been reading the copper chloride sheet from your site, thanks for providing so much helpful info and advice.

I placed an old fish tank bubbler in the AP (I hope the rubber tube will hold up).

Do you sell pure tin?

Thanks,
Turtle

 

[patnor1011]

If I will do that I will not add any additional H2O2. I think that you put way too much in there. I have very good results by adding about half of recommended amount and leaving solution working longer. That way I avoid too much of gold going into solution. You get your gold from solution later when this become saturated with copper as dark powder settling on bottom. You can get some if you leave solution stand as Barren said but if you want to get all dissolved gold your solution must be saturated with copper to push gold out.

 

[lazersteve]

Do you sell pure tin?

Turtle

Yes,

Check out my pricing page.

Steve

 

[turtle]

After all I was able to get 2 grams out of those five boards. Thanks for the assistance everyone.

Beachbum1975, no need to worry about the gun, I never really had full possession of that many. The place I work for never had a full recycle program / method for this type of stuff at our small site and for the most part some went in the trash or got stored in a room. Knowing what I know from my scrapping experience I recovered the five from the original photos from the dumpster one day and believed I could get more. We just learned they actually do have a recycle/recovery vendor but our site had been ignored for years. I guess it's better this way. Now I hope I don't get nailed for the 5 I found.

 

[beachbum1975]

Beachbum1975, ... The place I work for never had a full recycle program / method for this type of stuff at our small site and for the most part some went in the trash or got stored in a room. Knowing what I know from my scrapping experience I recovered the five from the original photos from the dumpster one day and believed I could get more. We just learned they actually do have a recycle/recovery vendor but our site had been ignored for years. I guess it's better this way. Now I hope I don't get nailed for the 5 I found.

Turtle, it's a darn shame your company has a recycling company that takes ALL your e-scrap (wink) !!! 2 grams of gold yielded from 5 boards amazes me! If I were you, I'd become the new "Dumpster Diver" more often (wink) ! The case holds true that one man's garbage is another man's treasure!

Personally, I've been working in IT for about the past 12 years in the greater Cincinnati area... I've never "burned any bridges" when I move onto the next company, so I've called several companies I used to work for to become their recycling company for the most part. I ask for the workstation/server/PC ONLY (they can continue to use their other recycling company to pick up their monitors, keyboards and other peripherals). The company I deal with is happy because I can be there with one day's notice and it cuts down on their overall costs to pay for ALL their e-scrap removal.

In fact, in the next few weeks, I plan to take my wife's mini-van downtown to pickup about 100 x P1, P2 and P3 workstations (CAN'T WAIT!!!). I've created a little harvesting/recovery shop in my basement where I process all the workstations. I keep what I call all the "green colored stuff" (motherboards, video cards, NICs, modems, memory CPUs, heatsinks, power supplies) and I have several large boxes labeled "aluminum", "steel", "dirty copper" and "clean copper" and "power supplies". I simply break down the workstation, sort into various boxes and take all but my "green colored stuff" to a local refinery for scrap!

I know there's recovery methods for all the other stuff (CRT monitors, keyboards, etc.) but I am just focusing on what I know, for now.

I hope this helps and good luck in your future e-scrapping endeavors!

Cheers,

beachbum1975