How is old CMOS logic manufactured today?

Thread Starter

RichardO

Joined May 4, 2013
2,271
Old fab lines are being shut down because they can't do the latest small feature processes.

This makes me wonder how the old parts are made. The main one that comes to mind is the 4000
line of CMOS. Others are the really old bipolar processes such as the uA741 and the like.

So, how and where are these dusty old parts made. Did the semi companies retool to make the parts economical using more recent technologies?
 

shteii01

Joined Feb 19, 2010
4,644
Interesting question.

I assume that those shiploads of 741 are coming out of China. Did the Western manufacturers shipped their fabs to China when they setup there back in late 80s and early to mid 90s? In that scenario Chinese are using old "original" fabs that were originally setup back in 60s or so.

Or did Chinese and their Western partners buy new equipment when they setup the Chinese fabs? In that case the equipment is only 20 or so years old.
 

Thread Starter

RichardO

Joined May 4, 2013
2,271
Maybe the parts are no longer being manufactured and we are just working through the EOL inventory buildup.
I have often wondered that as well. Especially all those 741's needed by engineering students. ;)

I doubt this is the case for what 4000 series CMOS is still available. But considering the decreasing availability...
 

nsaspook

Joined Aug 27, 2009
7,482
I don't think we need to worry, Russia is still making tubes that people want and buy. Parts that are still in demand (or under contract) will be redesigned for modern processes and re-qualified to the original specifications if not better for batch runs. Specialty/low demand products are a different story. I know of several fabs that closed to last year after final batch runs were completed. I would expect to see news of EOL parts from several consolidations this year.
 

jgessling

Joined Jul 31, 2009
82
I do know that complete fabs have been dissasembled and shipped out east. This from my experience at AMD. But I don't think they can produce forever unless there is a specific market. Will my 7400 stash become worth a million soon?
 

DickCappels

Joined Aug 21, 2008
6,535
I do know that complete fabs have been dissasembled and shipped out east. This from my experience at AMD. But I don't think they can produce forever unless there is a specific market. Will my 7400 stash become worth a million soon?
Yes, probably at the same time my RTL assortment becomes valuable again.
 

shortbus

Joined Sep 30, 2009
7,853
Why wouldn't the same "die" for a SMT chip be used? Just need to adjust the length of the internal "leads" out to the DIP package.
 

nsaspook

Joined Aug 27, 2009
7,482
Why wouldn't the same "die" for a SMT chip be used? Just need to adjust the length of the internal "leads" out to the DIP package.
That's just packaging usually. The manufacture of the "die" is a separate matter. There are still places that specialize in 'obsolete' parts or supplying parts the OEM has EOL'd from their own production lines.
http://www.lansdale.com/
https://www.rocelec.com/
 

Kermit2

Joined Feb 5, 2010
4,162
I saw the thread title and thought if it is manufactured today it is less than 1 day old, but the real question is how long will the surplus of obsolete chips last?
 
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