General > General Technical Chat
PCB black blob of glue ICs during the 70's-90's
RoGeorge:
I'm curious if those chip were of a particular technology, or if they were whatever size/technology was available back then, just that it was glued on a PCB instead of heaving their on case with pins and datasheets and everything else a standalone chip use to have.
Might be a personal bias, but I think those COB (Chip On PCB) were very low power compared even with today tech (batteries in such devices used to last for 5-10+ years).
What technology/size was that? Was it CMOS or something else?
Ranayna:
I think those CoB could have been just about anything. They were used because in mass production the price of an IC package was relevant, and CoB was cheaper, and repair/rework was absolutely irrelevant.
I do not remember where i read it, but supposedly labor costs in china were so cheap at some point, that the bonding and blobbing of such a chip was done by hand. And it was still cheaper than using a packaged IC.
tom66:
CoB is still common in cheap consumer electronics manufactured in ridiculous volumes. For instance my 1yr old Casio FX-83GTX calculator, which retails for about £15, has a CoB chip. The process is probably no different to a standard microcontroller (100 - 200nm range)
tooki:
--- Quote from: Ranayna on November 02, 2022, 02:20:06 pm ---I do not remember where i read it, but supposedly labor costs in china were so cheap at some point, that the bonding and blobbing of such a chip was done by hand. And it was still cheaper than using a packaged IC.
--- End quote ---
There are videos on YouTube showing how it’s done. A human places the die on the PCB and loads it into the wire bonding machine, which uses machine vision to identify the bond pads and then bonds them.
RoGeorge:
I suspect those chips were less advanced, something like um rather than nm tech. I wonder how far fetched would be to do that in a DIY manner, without ordering the dies from a chip fab.
It's been about 50 years since the blob chips started to be a thing, should be achievable with today DIY tech, isn't it?
Those chips were very low power, and for small automation there is no need for high integration scale. um would be enough. I'm still waiting for DIY chips similar with the nowadays 3D printing tech but for ICs, don't you? How far is that?
Navigation
[0] Message Index
[#] Next page
Go to full version