This article originally appeared on SemiMD.com and was featured in the March 2017 issue of Solid State Technology.

By Ed Korczynski, Sr. Technical Editor

As detailed in Part 1 of this article published last month by SemiMD, the inaugural Critical Materials Council (CMC) Conference happened May 5-6 in Hillsboro, Oregon. Held just after the yearly private CMC meeting, the public CMC Conference provides a forum for the pre-competitive exchange of information to control the supply-chain of critical materials needed to run high-volume manufacturing (HVM) in IC fabs. The next CMC Conference will happen May 11-12 in Dallas, Texas.

At the end of the 2016 conference, a panel discussion moderated by Ed Korczynski was recorded and transcribed. The following is Part 2 of the conversation between the following industry experts:

• Jean-Marc Girard, CTO and Director of R&D, Air Liquide Advanced Materials,
• Jeff Hemphill, Staff Materials R&D Engineer, Intel Corporation,
• Jonas Sundqvist, Sr. Scientist, Fraunhofer IKTS; and co-chair of ALD Conference, and
• John Smythe, Distinguished Member of Technical Staff, Micron Technology.

KORCZYNSKI:  We heard from David Thompson [EDITOR’S NOTE:  Director of Process Chemistry, Applied Materials presented on “Agony in New Material Introductions –  Minimizing and Correlating Variabilities”] today on what we must control, and he gave an example of a so-called trace-contaminant that was essential for the process performance of a precursor, where the trace compound helped prevent particles from flaking off chamber walls. Do we need to specify our contaminants?

GIRARD:  Yes. To David’s point this morning, every molecule is different. Some are very tolerant due to the molecular process associated with it, and some are not. I’ll give you an example of a cobalt material that’s been talked about, where it can be run in production at perhaps 95% in terms of assay, provided that one specific contaminant is less than a couple of parts-per-million. So it’s a combination of both, it’s not assay OR a specification of impurities. It’s a matter of specifying the trace components that really matter when you reach the point that the data you gather gives you that understanding, and obviously an assay within control limits.

HEMPHILL:  Talking about whether we’re over-specifying or not, the emphasis is not about putting the right number on known parameters like assay that are obvious to measure, the emphasis is on identifying and understanding what makes up the rest of it and in a sense trying over-specify that. You identify through mass-spectrometry and other techniques that some fraction of a percent is primarily say five different species, it’s finding out how to individually monitor and track and control those as separate parameters. So from a specification point of view what we want is not necessarily the lowest possible numbers, but it’s expanding how many things we’re looking at so that we’re capturing everything that’s there.

KORCZYNSKI:  Is that something that you’re starting to push out to your suppliers?

HEMPHILL:  Yes. It depends on the application we’re talking about, but we go into it with the assumption that just assay will not be enough. Whether a single molecule or a blend of things is supposed to be there, we know that just having those be controlled by specification will not be sufficient. We go under the assumption that we are going to identify what makes up the remaining part of the profile, and those components are going to need to be controlled as well.

KORCZYNSKI:  Is that something that has changed by node? Back when things were simpler say at 45nm and larger, were these aspects of processing that we could safely ignore as ‘noise’ but are now important ‘signals’?

HEMPHILL:  Yes, we certainly didn’t pay as close attention just a couple of generations ago.

KORCZYNSKI:  That seems to lead us to questions about single-sources versus dual-sourcing. There are many good reasons to do both, but not simultaneously. However, it seems that because of all of the challenges we’re heard about over the last day-and-a-half of this conference it creates greater burden on the suppliers, and for critical materials the fabs are moving toward more single-sourcing over time.

SMYTHE:  I think that it comes down to more of a concern over geographic risk. I’ll buy from one entity if that entity has more than one geographic location for the supply, so that I’m not exposed to a single ‘Act of God’ or a ‘random statistical occurrence of global warming.’ So for example I  need to ask if a supplier has a place in the US and a place in France that makes the same thing, so that if something bad happens in one location it can still be sourced? Or do you have an alternate-supply agreement that if you can’t supply it you have an agreement with Company-X to supply it so that you still have control? You can’t come to a Micron and say we want to make sure that we get at minimum 25% no matter what, because what typically happens with second-sourcing is Company-A gets 75% of the business while Company-B gets 25%. There are a lot of reasons that that doesn’t work so well, so people may have an impression that there’s a movement toward single-source but it’s ‘single flexible-source.’

HEMPHILL:  There are a lot of benefits of dual- or multiple-sourcing. The commercial benefits of competition can be positive and we’re for it when it works. The risk is that as things are progressing and we’re getting more sensitive to differences in materials it’s getting harder to maintain that. We have seen situations where historically we were successful with dual-sourcing a raw material coming from two different suppliers or even a single supplier using two different manufacturing lines and everything was fine and qualified and we could alternate sources invisibly. However, as our sensitivity has grown over time we can start to detect differences.

So the concept of being ‘copy-exactly’ that we use in our factories, we really need production lines to do that, and if we’re talking about two different companies producing the same material then we’re not going to get them to be copy-exactly. When that results in enough of a variation in the material that we can detect it in the factory then we cannot rely upon two sources. Our preference would be one company that maintains multiple production sites that are designed to be exactly the same, then we have a high degree of confidence that they will be able to produce the same material.

GIRARD:  I can give you a supplier perspective on that. We are seeing very different policies from different customers, to the point that we’re seeing an increase in the number of customers doing single-sourcing with us, provided we can show the ability to maintain business continuity in case of a problem. I think that the industry became mature after the tragic earthquake and tsunami in Japan in 2011 with greater understanding of what business continuity means. We have the same discussions with our own suppliers, who may say that they have a dedicated reactor for a certain product with another backup reactor with a certain capacity on the same site, and we ask what happens if the plant goes on strike or there’s a fire there?

A situation where you might think the supply was stable involved silane in the United States. There are two large silane plants in the United States that are very far apart from each other and many Asian manufacturers dependent upon them. When the U.S. harbors went on strike for a long time there was no way that material could ship out of the U.S. customers. So, yes there were two plants but in such an event you wouldn’t have global supply. So there is no one way to manage our supply lines and we need to have conversations with our customers to discuss the risks. How much time would it take to rebuild a supply-chain source with someone else? If you can get that sort of constructive discussion going then customers are usually open to single-sourcing. One regional aspect is that Asian customers tend to favor dual-sourcing more, but that can lead to IP problems.

[DISCLOSURE:  Ed Korczynski is co-chair of the CMC Conference, and Marketing Director of TECHCET CA the advisory services firm that administers the Critical Materials Council (CMC).]

—E.K.