I Took Apart A PIC18 - Page 1
Forum section: electronics / general

author: Lance
author_rank: Frequent Contributor
timestamp: September 22, 2010, 06:27:20 pm
content: Following the motto of this site, I didn't turn it on! I tried to turn it on, discovered it was burnt out, and then took it apart. The component in question is a PIC18. I just sanded the top off until I got down to the lead layer. I didn't have a proper sander available to me, so I just went at it with a sandpaper bit on a drill. A few times the drill got traction and pulled around, so some of the pins got wrecked. All things considered it came out rather well. Not a neat job by any means.Did I destroy the IC? Or can I lightly remove some more to get at it?

author: Time
author_rank: Frequent Contributor
timestamp: September 22, 2010, 06:33:21 pm
content: Why did you sand the solder mask off?

author: armandas
author_rank: Frequent Contributor
timestamp: September 22, 2010, 06:52:58 pm
content: Dude, picture cropping - use it!!Back to topic: interesting picture, thanks for sharing. I have extracted the silicon parts by torching ICs. It's not too fascinating without a microscope though.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: September 22, 2010, 07:07:26 pm
content: SparkFun has had a few recent columns on dissecting ICs. The first, a few months ago, was looking at SD cards. The second was a counterfeit ATMEL part. Lots of awesome pictures and a discussion about how the pros do it.

author: Time
author_rank: Frequent Contributor
timestamp: September 22, 2010, 07:08:07 pm
content: Oh, nevermind I see whats going on here. This is an IC, I thought it was PCB for some reason.

author: Lance
author_rank: Frequent Contributor
timestamp: September 22, 2010, 08:07:25 pm
content: Yeah I was wondering why you said that.So how do I actually get the IC out? What else needs to be taken off? Is the grey there just more plastic to remove?

author: armandas
author_rank: Frequent Contributor
timestamp: September 22, 2010, 08:43:48 pm
content: Quote from: Lance on September 22, 2010, 08:07:25 pmIf you just want to get the silicon out, burn the thing with a torch. By sanding, you're more likely to scratch the die.

author: Lance
author_rank: Frequent Contributor
timestamp: September 22, 2010, 08:55:31 pm
content: I would like to keep it in the body...perhaps turning it upside down and having a small flame would work? I'll do some research.

author: Zad
author_rank: Super Contributor
timestamp: September 22, 2010, 10:25:29 pm
content: The guy athttp://www.visual6502.org/used hot sulphuric acid to remove the encapsulation on the 6502 (woah!).

author: Unknown
author_rank: Unknown
timestamp: September 22, 2010, 11:35:24 pm
content: Yep, strong acid is the proper way. As someone who has worked with that kind of stuff (not for taking apart semiconductors), I wouldn't recommend anyone without proper training and equipment (fume hood, eye wash, that kind of stuff) to even get near it. It's far more dangerous than even mains voltage. A blow torch is much safer (as long as you don't burn yourself and it's outdoors).

author: Lance
author_rank: Frequent Contributor
timestamp: September 22, 2010, 11:55:05 pm
content: Quote from: alm on September 22, 2010, 11:35:24 pmI'm confident I could handle it properly, but I don't have a proper fumehood or emergency eye wash station. So I'd rather not use that kind of acid. Also I don't have any on hand. Quick use of a torch seems to be the best way to go about this for me.Perhaps Dave could do a blog on this.

author: Zad
author_rank: Super Contributor
timestamp: September 23, 2010, 01:10:01 am
content: I wish I had a macro lens, I have some old PIC12 and PIC16s that were UV erasable and so have a quartz window over the chip. The detail you can see just with a hand lens from a Swiss Army Knife is amazing!

author: Lance
author_rank: Frequent Contributor
timestamp: September 23, 2010, 05:24:04 am
content: Quote from: Zad on September 23, 2010, 01:10:01 amI can imagine. I'll take a look around and see if I can find something like that. I've never heard of UV light being used to erase the EEPROM, although that would explain why I have seen ICs with windows on them. How does the UV light erase the memory?

author: joelby
author_rank: Frequent Contributor
timestamp: September 23, 2010, 05:32:16 am
content: Quote from: Lance on September 23, 2010, 05:24:04 amUV light is used to erase EPROMs, not EEPROMs.QuoteThe UV light ionises the silicon oxide in the chip, which causes the charge stored in the floating gate to dissipate.

author: Zero999
author_rank: Super Contributor
timestamp: September 23, 2010, 08:04:10 am
content: It does show how tiny the die is compared to the package.Perhaps Microchip should offer a chip on board option for high volume designs: submit the PCB design and the code and they'll get it made for you.I've done this before. Where I used to work there were some old 741s in a metal case, all I did was cut the top of but unfortunately I didn't take a picture.If you have a scanner, it's probably the best way to take pictures of small flat objects.

author: joelby
author_rank: Frequent Contributor
timestamp: September 23, 2010, 08:13:05 am
content: Quote from: Hero999 on September 23, 2010, 08:04:10 amMicrochip (and Atmel) will sell you bare dies, if that's what you mean. I doubt they want to be in the business of making your PCBs for you!

author: DavidDLC
author_rank: Frequent Contributor
timestamp: September 23, 2010, 04:08:24 pm
content: Quote from: joelby on September 23, 2010, 08:13:05 amUnless they can get a very good deal, like with big companies, then they can outsource the assembly.