The eight-inch advantage: MEMS development at SVTC
Q: What’s new at SVTC?
with Scott Marquardt
Our story is all about 8-inch. We’ve had a number of people come and do development of MEMS products; they’ve learned a lot, and we’ve learned a few things. We think there are some core lessons about 8-inch. There’s a lot of speculation and a lot of talk, but the reality is very few people actually know how.
There were advances between the era of 6-inch tools and 8-inch tools, so many processes don’t actually translate directly. It’s not like you can just port the recipes from one tool to the other. There are some unique challenges from a process transfer standpoint, but also other factors such as how larger wafers bow more easily and the higher stresses involved. To produce successfully on 8-inch, you have to rethink certain things.
For people doing development, we can certainly assist in those things, but every product and every project has its own unique characteristics and putting those up against 8-inch tools, there are things to learn. You can’t just take what you’re doing in 6-inch and send a diagram off to TSMC and say, ‘Please make me 10 million of these.’ (Laughter).
Q: Why would people want to work on 8-inch processes compared to 6- or 4-inch?
There are a number of reasons, but the one that is most compelling we’ve seen is where the MEMS devices have a high level of integration with transistors or other logic. The example I like to give is with micromachined mirrors and the mirror arrays. The mirror arrays have a very high bandwidth because you have to have something flipping each mirror array, and to conceive that in an interconnect is unimaginable. So all of these are built up on top of the base CMOS. To be able to run MEMS processes on a 0.18µm or better CMOS process, either on top of or along side or underneath, is probably one of the most compelling reasons to process on 8-inch.
We are also finding there are people who have need for greater precision. Even though the MEMS geometries are typically well within the range of 6-inch tools, the precision needed for multiple layers may require more advanced processing.
There are general economic advantages as well, such as higher volume and lower cost of production. Another advantage is the large infrastructure for 8-inch fabs. The disciplines of that supply chain, such as multiple sourcing, will ultimately benefit MEMS producers.
Also, there are new things in 8-inch that don’t exist in 6-inch. The one we mention most frequently is atomic layer deposition (ALD). Although ALD came into being more for high-k and metal gate in CMOS, the variety of metals and materials that can be deposited in very thin layers have other applications, for example in reducing stiction and controlling stress.
Q: You recently added capabilities with other tools as well, such as etch and bonding?
Right. There are some new techniques in tools???some of which are in the general semiconductor CMOS equipment portfolio at 8-inch that did not exist at 6-inch???that offer greater capability, including ALD and higher precision. The new bonders can operate at higher pressures.
Q: If someone has an idea for a MEMS device, how do they work with you?
100% of the people that come here have developed the technology to some extent in a lab setting, many from either Berkeley or Stanford but projects have come here from further afield as well. These are usually technologies that have been developed in a smaller format lab environment, as small as 2-inch or 4-inch wafer sizes on lab type tools. Then they come here.
Commercializing these on 8-inch production tools takes time and many cycles of learning. What is happening is not so much groundbreaking research but actually getting everything to work together properly, so that eventually you can hand the formula to a foundry and run within the tolerances of their production tools.
SVTC Technologies is an independent semiconductor development foundry that enables the development and commercialization of innovative semiconductor-based technologies and products in an accelerated, cost-effective and IP-secure way. The company recently expanded its capabilities to enable customers to move toward the next generation of MEMS processing, adding new equipment from Lam Research Corp. and SUSS MicroTec to extend its deep silicon etch, wafer bonding, proximity alignment, and additional microlithography capabilities. Small Times caught up with SVTC’s Scott Marquardt, VP of sales, marketing, and strategic business development, who has helped drive more than a half-dozen start-ups and turnarounds in the US, Europe, and Asia???most recently as SVP of sales and marketing for Asia Pacific with NXP