Decapping, imaging, and reverse engineering all the 54xx/74xx chips

[robertbaruch]

Well, as many as I can get my hands on. It's fun. Yes, it's going to be a lot of work and I will likely not get to every number and variant, but I plan to do a lot. I'm putting all the info on project5474.org. Why? Why do we do anything? ¯\_(?)_/¯

[Vgkid]

I look forward to your updates.

[ebclr]

Will be interesting to see different manufacturers for same part  imaging, to check what they do diferently

[bitwelder]

It would be interesting also to read about the process and the equipment used.

[MK14]

That sounds like an interesting and fun project.

I hope you manage to get around to the 74181 (74182 is probably fairly rare), 4 bit arithmetic logic unit, and its partner, the 74182 is a high speed carry look ahead generator.

I'm also interested in the differences, between the original 7400 series, and the S (Schottky) and LS types.

[SingedFingers]

74LS469 is rumoured to be an interesting one. Apparently it's actually a PAL, not custom silicon.

[free_electron]

I hace somwhere a 74 series 16x16 multiplier in 64 pin humonguous package ...

[pyroesp]

Favorited the website for future read.

Do you have a list of ICs you currently have/don't have ?

I hope you manage to get around to the 74181 (74182 is probably fairly rare), 4 bit arithmetic logic unit, and its partner, the 74182 is a high speed carry look ahead generator.

From my IC list I've made quite a while back, I've got four 74181 and three 74182. Don't know what type (S, LS).

I'm also interested in the differences, between the original 7400 series, and the S (Schottky) and LS types.

Above mentioned list, it seems I have thirty 7400, I'm guessing I should have all sorts.

If OP wants to and is willing to pay for shipping cost, I'll send a few of those I have in surplus to him.

[robertbaruch]

I have a list of ICs.

Also I have a Patreon.

[robertbaruch]

I do eventually plan to put the full processes I use on the wiki -- I currently only have "Heat", "Delayering", and "Annotation", still working on "Imaging" and "Hot Sulfuric Acid". But a lot of the information is on my (separate) blog if you're interested.

If you do have chips that aren't on the spreadsheet, please let me know!

[RoGeorge]

Does anybody know what/why are those "bubbles like" dots, and why are those present only on the white traces, please?

[robertbaruch]

From what I've seen, they seem to be on every top metal layer. Maybe it's just that the process used for depositing metal leaves a lot of gaps. So then they would run the depositing stage for longer to ensure a solid connection. Just a very rough surface.

In one decap session, I removed the top glass layer by etching it for a very long time. I got under-etch underneath some of the metal connections, which caused the connections to lift off the surface. There were still those bubbles on the surface of the metal, so I'm pretty sure it's not on the glass.

[amyk]

The '181 has already been done: http://www.righto.com/2017/01/die-photos-and-reverse-engineering.html

[MK14]

The '181 has already been done: http://www.righto.com/2017/01/die-photos-and-reverse-engineering.html

Thanks!
That is a really great investigation and report into what is inside a 74181. Their detailed explanation of how the transistors work, to make the overall circuit, is just brilliant!
Anyway, nice find.

If decapping TTL chips. The 74181's would still be the (top) one to go for, on the basis that it is one of the biggest and most complicated (of the "older" TTL chip parts). It has a lot of the functionality of a microprocessor, and yet was released before them and used in many historically important computers, of the time.
I.e. It is so big and functional, that it makes it very interesting.
Simple gates, e.g. 7400 Quad Nand, are still interesting. But the very complicated ones (like the 74181), add a lot to how interesting it is (at least for me).

I'm not sure if the OP is going to only do TTL chips which have not yet been publicly decapped, or if they are doing them all, regardless. I get the impression they (OP) are doing this independently of any other works, available on the internet.

[robertbaruch]

I know the guy who did the '181, he also gave me a '182. I think his work on the 181 is good enough to put on project5474, but basically I'm shooting for doing independent work, on whatever I can find. Not necessarily sticking with the older ones, though. They are still making new 74-series chips all the time, and there are still lots above the 74700 range.

[robertbaruch]

LOL, I just realized: I don't turn on TTL chips, I take 'em apart.

[MK14]

LOL, I just realized: I don't turn on TTL chips, I take 'em apart.

You're turning them into ALZ chips.
Where A.L.Z. = Always Logic Zero = Permanently Disassembled (a.k.a. Broken).

TTL = Transistor Transistor Logic
Where Transistor in this case = Acid Dissolved Case = ADC = Always Digital Clear = Logic Zero