Die extraction and reuse

[blueskull]

I have a particularly interesting question...

How possible it is to extract a die from its molded package? Say, an 8P DFN.

Essentially, 2 things must be guaranteed:

1. No die surface damage
2. No bonding pad (Al) dissolving

Since the bond wire is copper, I'm sure it will be dissolved as part of the leadframe dissolving process, so I'm pretty sure I don't have to yank it manually.

I'm open to specialty solvents (Dynaloy 711/Decap/etc.), acid (hot H2SO4, warm HNO3, mix), milling and a mix of them. Cost is not a concern as long as in a small batch run, the cost per die is less than $10.

I can just buy the die I'm interested, but the price from Micross is not what I would like to pay ($50+ per 1.0mm*1.2mm opamp die).

FWIW, the post process after decapping is bumping with a gold ball bonder, then reflow with a gold friendly solder.

[NiHaoMike]

I take that you're really desperate at cutting every last cubic millimeter?

[amyk]

https://www.bunniestudios.com/blog/?page_id=40

Careful etching can reveal the die in a functional state, but getting it out may be a bit more tricky...

[Amper]

From my experience you will first have to cut away as much as you are comfortable doing. Dissloving large ammounts of plastic for a total extraction will have chunks floating around in your acid damaging the surface of the chip if you are not really careful. I would try to first open it up mechanically from the back and adhesive mount the die from the backside to some jig to hold it in place while dissolving the plastic and frame around it.

[David Chamberlain]

Something nefarious going on if you can't just ring the manufacture and ask to purchase bare dies?

[T3sl4co1l]

Something nefarious going on if you can't just ring the manufacture and ask to purchase bare dies?

I expect this relates to his ongoing audiophile DAC project, which is going to be a hybrid module I think??  Hence the need for bare dies.

As a hobby project, it's not going to be cost effective to:
- Buy a wholesale crate of (diced) wafers
- Buy single dies at a time (at "we don't want to sell you these quantities" markups)
And it is going to be effective to:
- Discount ones' free time to zero labor (maybe)
- Buy packaged parts and strip them (if possible)
- Figure out some way to use packaged parts anyway (maybe not possible)

At least that's what I'm guessing.

FWIW, the post process after decapping is bumping with a gold ball bonder, then reflow with a gold friendly solder.

So, a flip-chip approach?  And, if not hybrid, then fine pitch PCB just as well.  Interesting...

Tim

[Wimberleytech]

I have a particularly interesting question...

How possible it is to extract a die from its molded package? Say, an 8P DFN.

Essentially, 2 things must be guaranteed:

1. No die surface damage
2. No bonding pad (Al) dissolving

Since the bond wire is copper, I'm sure it will be dissolved as part of the leadframe dissolving process, so I'm pretty sure I don't have to yank it manually.

I'm open to specialty solvents (Dynaloy 711/Decap/etc.), acid (hot H2SO4, warm HNO3, mix), milling and a mix of them. Cost is not a concern as long as in a small batch run, the cost per die is less than $10.

I can just buy the die I'm interested, but the price from Micross is not what I would like to pay ($50+ per 1.0mm*1.2mm opamp die).

FWIW, the post process after decapping is bumping with a gold ball bonder, then reflow with a gold friendly solder.

You are nuts, but go for it:

[Amper]

Decapping will not be enough for him if he wants pure dies! Just getting to the die for playing with it is one thing, getting rid of everything else is a different story in terms of being careful not to damage it. you need to somehow grab onto the bare die to not have it fall in the bath when the case is gone.