From Cutting-Edge to Legacy to Scrap: The Life Cycle of Semiconductor Fab Equipment

once, I was attending a lecture related to CMOS fabrication, and I had a curious question in mind. What do fabs do with old factories or equipment for outdated technology nodes when they are no longer in use? In other words, if a fab facility decides that a particular technology node is no longer in service, what happens to the equipment that is used to manufacture chips with that node? Do they recycle it or dispose of it as scrap metal and plastic? ??

I did some research and asked around until I came to understand the general situation. And I hope someone with direct knowledge in this area can provide more insight into this question ??.

First, before we ask what happens to the equipment or factories that have been retired, let's consider when we can say that a factory or technology node is no longer in use. Currently, we have reached a technology node of 3 nanometers. Does that mean they've abandoned 5 nanometers, 7 nanometers, and 10 nanometers altogether? And what about legacy technologies like 180 and 130 nanometers, which have been introduced more than two decades? Could someone still be producing chips with these technologies today? This is an important question too.

Also certainly, the machines capable of producing 5 nanometer chips could also produce 10 nanometer and 180 nanometer chips relatively easily. So, does that mean they'll eventually have to dispose of the older equipment? ??

The first question is, Which technology node is considered old enough to dispense, and do any of the top foundries use these older nodes nowadays?

This infographic from counterpointresearch.com below shows the foundry revenue share by technology nodes in the second quarter of 2022 this should be the peak year of the 5nm technology node but on the other hand, many other technology nodes are taking big parts even the 65 nm which was introduced in 2005 still have 9% of the revenue share.

So, 65nm is the oldest one ???

?Wait Wait I'll share with you some good information

Impossible are technologies like 0.25 microns and above are still alive!

?The rest of the question was: do any of the top foundries use these older nodes nowadays?

Do you know which the above revenue is for which fab? ??

?It's for the biggest and the most important fab. it's for TSMC and regarding the old 0.25 microns they are still manufacturing and gaining money even in the current year 2023 the last quarter of the year Q2 tsmc presented this slide showing that 0.25um and above take 1% of the revenue and the 180nm also takes a good share of 5%. and the 3rd quarterly revenues will be presented within less than two weeks from now and you'll see that these old technologies are still there.

Ok, this is TSMC but are there any other big fabs that offer these legacy technology nodes?

?Not only TSMC but also the other famous fabs do. Here's the 1st and 2nd quarterly of the year 2023 for UMC showing they are still using older nodes.

?This one is for the 3rd and 4th quarterly of the year 2021 for SMIC (and this is the last year they announce their revenue by technology but obviously they are still offering these nodes)

?But, Why are these technology nodes still offered? and my old question Do they offer these technology nodes using the old equipment or the new ones? technically the equipment that can make 5nm and 3nm can make 180nm and 130nm.

?Before answering let me ask another question who needs advanced technology nodes like 7 nm, 5nm, and 3nm?

Actually, there is a small punch of companies who need to constantly manufacture chips on the most cutting-edge technology nodes like (Apple, MediaTek, Nvidia, Intel, AMD, Samsung, Qualcomm, etc.)

However, the other major number of companies are still OK with the older nodes as they are cheaper and abundant and the newer technology nodes won't differ so much in the performance of their products so why put more money?

Not all the companies in the world are designing high-performance CPUs and GPUs that need these modern technologies but there are many other applications that can use older technologies like power ICs, flash memory, microcontrollers, signal processing, MEMs, Sensors, so even big companies like TI, ST Microelectronics and ADI aren't in a continuous need of the cutting edge nodes. and industries like Automotive and IOT I think they are satisfied with the older ones as there is no need for N3 for my car window power or my washing machine I think if there are washing machines using 3nm chips I'll respect it more than I did with mine. ??

?So, fabs offer these technologies for their customers in different fields. For TSMC, not all the fabrication is for logic technology but there are many other Specialty Technologies like MEMS ranging from 0.5-micron (μm) to 0.11μm, Embedded Flash technology ranges from 0.5-micron (μm) to 40nm, Analog process technology from 0.5μm to 16nm for applications including smartphones, tablets, automotive electronics, computers, audio, electronic medical equipment and home appliances, and more...

?The majority of wafers in high-performance computing (HPC) applications apply cutting-edge technology nodes and have customers like Apple, Intel, AMD, Nvidia, Marvell, Broadcom, etc.

Do they offer these technology nodes using the old equipment or the new ones? technically the equipment that can make 5nm and 3nm can make 180nm and 130nm.

?Technically the equipment can probably do this mission but the yield of the mature processes is very good compared with the new ones also money is important if they make it using the new equipment it'll cost more and I think there aren't such a big number of new equipment to make the cutting edge nodes and the legacy nodes and this will result to a hard bottleneck as all of the capacity for old nodes that will ever be built has been built – and they won't be building anymore and new companies are opened so the bottleneck will come definitely and they can't make some of the chips using the older processes and some other using the newer ones as this will result in different prices for the same technology. so, the solution is to convince the world to move from the old technologies to newer ones and this already happened for example, TSMC has recently begun strongly encouraging its customers on its oldest (and least dense) nodes to migrate some of their mature designs to its 28 nm-class process technologies. (from AnandTech)

?So, for now, older technology nodes are still in the match but what about the oldest which already took the red card, and what do we predict to these older ones as many modern applications have upgraded to newer technology nodes of course one day they'll stop them.

?This may have many scenarios and every fab typically has its own procedures for handling old machines and equipment these procedures may differ somewhat from one fab to another, but they generally follow some common practices:

-->Decommissioning: After the decision to retire the machine it should go through the decommissioning process which involves shutting down, disconnecting from the fab's infrastructure (such as power and gas lines), and ensuring it is safe for removal.

-->Evaluation and Testing: Before deciding on the fate of the equipment, fabs often evaluate its condition and functionality. If it can be refurbished or repurposed, the fab may choose to do so. Otherwise, it may be deemed obsolete and ready for disposal.

?Here the fab should decide what will happen to the machine and the decision will be from one of the below options:

-->Refurbishment and Repurposing: Fabs can be upgraded to serve a newer technology node which is known as "Technology Migration" and this is done by investing in refurbishing, upgrading, or totally reconfiguring the equipment.

-->Cannibalization for Spare Parts: it's another way of repurposing, fabs may keep some old machines as a source of spare parts to maintain their existing equipment. This can be cost-effective in the long run.

-->Resale: Resale! yes, resale is an option I also was amazed and this was my first question can someone buy the old machine? Fabs may choose to sell their old equipment on the secondary market. Other semiconductor fabs, research institutions, or smaller manufacturing facilities might be interested in purchasing older machinery at a reduced cost. The fab may not appear with its own name but it can work with equipment brokers to facilitate resale.

There are even websites for this mission:

-->R&D and Training: Older fab can be kept for research and development or for training new employees. and these fabs can be a valuable environment for testing and experimentation without the pressure of high-volume production.

-->Donations or Grants: fabs may be such a kind and donate old equipment to research facilities or educational institutions to support scientific and academic endeavors. and some people consider this should be done as a part of a corporate social responsibility effort and also this fosters collaboration with academia.

-->Recycling: For equipment that cannot be resold or repurposed or invalid for R&D or donation (not cool enough ??) disassembling and recycling may be an option. And of course, these big companies are conscious of environmental regulations (I think so) and aim to responsibly dispose of or recycle materials and components to minimize the environmental impact of semiconductor manufacturing.

?Finally you should know whatever option the fab chooses there is something very important to consider which is Data Security, fabs take this seriously, in the semiconductor industry protecting the details of the fabrication process, intellectual property, and customer designs is very important. so before any of the above options, fabs take steps to ensure that any sensitive data stored on the machines is securely wiped or destroyed to prevent data breaches. (And I think this makes the fabs put restrictions on the resale process in some parts of the world)

?OK, That's all I have for today, my friend. If you are opening your fab don't forget to invite me to the opening to have a look ??