Custom IC - Page 1
Forum section: electronics / general

author: frog
author_rank: Contributor
timestamp: October 20, 2017, 08:54:57 am
content: Hi All,I have a (discrete component) analogue design for a high-volume product and I want to investigate getting a custom IC made. Can anyone suggest where to start?Thanks,Frog

author: Berni
author_rank: Super Contributor
timestamp: October 20, 2017, 09:13:36 am
content: You start by picking up a few million dollars out of your bank account to pay for it.

author: capt bullshot
author_rank: Super Contributor
timestamp: October 20, 2017, 09:18:32 am
content: You should look for a company that offers such designs as a service to you. Maybe a well known semiconductor manufacturer, or a rather small design house, both ways exist. Don't expect your analog circuit to be literally transferred, the usual way is to start from scratch with functional and non-functional requirements.

author: grifftech
author_rank: Frequent Contributor
timestamp: October 20, 2017, 02:45:49 pm
content: DO NOT MAKE A CUSTOM IC if the company you ordered them from goes out of business...

author: Jeroen3
author_rank: Super Contributor
timestamp: October 20, 2017, 05:27:32 pm
content: Define high volume? Does this also include low cost?

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2017, 05:45:03 pm
content: Quote from: Berni on October 20, 2017, 09:13:36 amYou are making assumptions. If the device has a low complexity, and doesn't prove hard to model, and is economical in a coarse geometry he might only need a few hundred thousand dollars.

author: AndyC_772
author_rank: Super Contributor
timestamp: October 20, 2017, 06:03:48 pm
content: What benefit are you looking for in the custom IC?Just price per unit? Or is there a technical performance metric that you're looking to try and improve at the same time?I've always assumed that custom ICs are inevitably silly money, but I have no first hand experience with them.

author: frog
author_rank: Contributor
timestamp: October 20, 2017, 08:41:00 pm
content: Volume is likely to be up to 100k per year over a 5-10 year lifespan

author: frog
author_rank: Contributor
timestamp: October 20, 2017, 08:42:13 pm
content: Quote from: AndyC_772 on October 20, 2017, 06:03:48 pmBenefits could be cost reduction, simplified BOM, improved MTBF and preservation of IP.

author: frog
author_rank: Contributor
timestamp: October 20, 2017, 08:43:58 pm
content: Quote from: capt bullshot on October 20, 2017, 09:18:32 amThat's more or less what I had in mind. Does anyone here have any experience in doing this, and could they suggest who to contact as a starting point?

author: wraper
author_rank: Unknown
timestamp: October 20, 2017, 08:53:44 pm
content: If you want 100k per year, I don't think how it would reduce the cost. It would be exactly opposite, unless your current BOM is very expensive and custom circuit could do that all while not being complex by itself.

author: frog
author_rank: Contributor
timestamp: October 20, 2017, 09:07:37 pm
content: Quote from: wraper on October 20, 2017, 08:53:44 pmIt's not very complex, perhaps 40 semiconductor junctions.

author: wraper
author_rank: Unknown
timestamp: October 20, 2017, 09:14:06 pm
content: What sort of analog circuit it should replace? What current BOM cost do you intend to replace with this IC?

author: chris_leyson
author_rank: Super Contributor
timestamp: October 20, 2017, 09:19:41 pm
content: I think most of the stuff from IC-HAUS in Germany is custom bipolar, might be worth asking them.

author: coppice
author_rank: Super Contributor
timestamp: October 21, 2017, 12:24:06 am
content: Quote from: frog on October 20, 2017, 08:41:00 pmIts very unlikely a custom device is going to work out well for you with such a low volume. You'll also have all the risks associated with custom development, and the hassles of achieving good prediction of your needs to ensure timely wafer starts. Off the shelf parts greatly simplify your BOM.

author: jmelson
author_rank: Super Contributor
timestamp: October 21, 2017, 10:40:58 pm
content: MOSIS at USC has a service where they combine designs from many groups onto one wafer and get it fabricated in a variety of processes. We have had some pretty complicated designs done through them. A medium-size chip on the ON Semi C5 process runs us about $25000for 40 chips. Adding more chips costs a couple thousand $ for 40 more. Once you have the design 100% perfected, you can have them do full wafers of just your design at a much better price.One trick is to just order 40, and then get all the rest of the parts off the wafer and possibly additional (safety) wafers that were run. These chips will be available very cheaply, but cannot be counted on to have made it through the process.Watch out, the packaging fees can also be expensive.Jon

author: jmelson
author_rank: Super Contributor
timestamp: October 21, 2017, 10:47:37 pm
content: Quote from: AndyC_772 on October 20, 2017, 06:03:48 pmWe have made several custom chips for signal processing in nuclear science experiments. There are reasons the system needs to be made small. We have several thousand channels of signals coming in. Some conventional off the shelf electronics would have cost several millions of $. We got 256 channels into a shoebox sized housing using the custom chips. Total cost was probably over $100K, and we can put all the gear in a big plastic box and send it via FedEx to the accelerator site.But, it was a big hassle to work through the quirks on each chip. All of the versions functioned to some extent, but always needed some kind of outside trickery to work around some issue in the chip design or performance. Once you spend $40K to have a couple hundred custom ICs fabricated, you don't want to trash them, so you have to come up with external hacks to get around the errors.Jon

author: coppice
author_rank: Super Contributor
timestamp: October 21, 2017, 10:54:16 pm
content: Quote from: jmelson on October 21, 2017, 10:40:58 pmThat's fine if you want something for which the On Semi C5 process is suitable. Designs don't migrate across processes, though. Change processes and you need to start your analogue design from scratch. The HDL for your digital stuff will carry over, but timing will be so different there will be a lot of work there too.

author: jmelson
author_rank: Super Contributor
timestamp: October 21, 2017, 10:55:44 pm
content: Quote from: frog on October 20, 2017, 09:07:37 pmHmmm, are you sure you can't do this with a few op amps and discrete transistors in SMT format? The costs for an IC are all in the mask generation, and this doesn't change much depending on size. So, while MOSIS charges mostly by the square mm for the combined runs, when you go to dedicated wafer runs, you pay for the entire mask set yourself, at somewhere in the range of $250K to 500K (might even be more today!) So, for 100K parts, you spend 2.5 - 5 Dollars per custom chip, at least the first year. Having your SMT board made in China in bulk could probably be way less than that, and you could have your parts arriving within a couple months. With a custom IC, you would likely wait 6 months or more to have the first batch of completed boards. But, that's only if your first IC was perfect the first time.Jon

author: jmelson
author_rank: Super Contributor
timestamp: October 21, 2017, 10:59:49 pm
content: Quote from: coppice on October 21, 2017, 10:54:16 pmMOSIS offers something like 40 different processes from about 8 different fabs. Most of these are trending toward ultra high-density digital processes, but they have a couple that are good for mixed signal, too. Yes, it is best to stay with one process for the lifetime of a project.MOSIS has ON Semi, IBM, Austria and TSMC among others.Jon

author: coppice
author_rank: Super Contributor
timestamp: October 21, 2017, 11:03:45 pm
content: Quote from: jmelson on October 21, 2017, 10:55:44 pmSub-micron digital masks cost a lot, but most simple analogue designs use much coarser processes. They just can't benefit from smaller devices. The mask set might only be a few 10s of k.

author: frog
author_rank: Contributor
timestamp: October 22, 2017, 12:22:28 am
content: Quote from: jmelson on October 21, 2017, 10:55:44 pmThat's what I'm hoping. I think I have a few leads to go on - thanks everyone for your input.

author: coppice
author_rank: Super Contributor
timestamp: October 22, 2017, 01:35:34 am
content: Quote from: frog on October 22, 2017, 12:22:28 amThe mask set might be a few 10s of k, but you are still going to need a big pot of money for everything else. I questioned jmelson's mask costs, but overall he's right. For your modest volumes a solution using off the shelf parts is almost certainly cheaper.

author: coppice
author_rank: Super Contributor
timestamp: October 22, 2017, 02:37:38 am
content: Quote from: blueskull on October 22, 2017, 02:25:09 amThe OP seems to need pure analogue. For pure analogue above micron is alive and well, especially when you need bipolar transistors. There is just no upside in fine geometries for some part.

author: frog
author_rank: Contributor
timestamp: October 22, 2017, 03:02:17 am
content: Yes that's right, pure analogue. Since people seem to be able to make high-voltage transistors there must be a process that can accommodate it.

author: jmelson
author_rank: Super Contributor
timestamp: October 22, 2017, 04:00:12 am
content: Quote from: coppice on October 21, 2017, 11:03:45 pmNo way! Nobody can get even a simple mask set for under $100K. And, I doubt you can find any fab that will do 1 um or larger process, there just isn't any demand. The various services that can do these combined runs have specific processes and design rules they will accept.Jon

author: mairo
author_rank: Unknown
timestamp: October 22, 2017, 04:00:55 am
content: As blueskull have pointed out companies like Diode Inc, ON and ST offer such services.Some other useful links:http://www.towerjazz.com/https://www.globalfoundries.com/http://kokomogmch.com/https://www.xfab.com/home/http://www.semefab.com/http://isipkg.com/

author: coppice
author_rank: Super Contributor
timestamp: October 22, 2017, 09:58:53 am
content: Quote from: jmelson on October 22, 2017, 04:00:12 amYou seem to be thinking in digital terms. Think analogue, especially analogue with fairly high voltage transistors. Its a different world, with different players. Most companies dropped their coarse analogue processes years ago, but the niche players who focus on true analogue (as opposed to the people saying they are big in analogue, while their parts are really mixed signal) are still there.

author: jmelson
author_rank: Super Contributor
timestamp: October 23, 2017, 07:59:03 pm
content: Quote from: jmelson on October 22, 2017, 04:00:12 amOK, maybe I should expand on this. We use the ON Semi C5 process (used to be AMI semiconductor). It is a fairly advanced mixed-signal process, perfect for the stuff we are doing. It does have quite a few more layers than plain CMOS, so high resistance and high capacitance layers can be fabricated. This does drive up the cost of the mask set. But, it sounds like this is the kind of process that the OP might need, anyway. The C5 process is NOT designed for bipolar, the only bipolar function we have is a band gap reference. People have fabricated other bipolar parts on it, but those parts are not in a library we have access to.The chips we are doing have very roughly 100K transistors, so quite a bit larger than the OP's project.Jon