CEA-Leti: The Mother Ship Re-visted

Last time I visited Leti on the Minatec Campus was in October 2009.  Recently, when I was back for Leti’s Annual Research Reviews, Mark Scannell, head of the 3D integration program, took me on another tour. A lot has been going on here in the past 2 years. For one thing, the building I saw going up in its early stages has been completed.  There’s now a showroom displaying all the nifty new products made possible by Leti-developed technologies.  And the 300mm 3D cleanroom came on line in January, and sports some impressive new tools.  I have to say the best part though, was the new class 1000 clean train that transports staff and wafers from one cleanroom to another eliminating the need to dress and undress. According to Thierry Mourier, 300mm line for 3D project leader, this futuristic form of transportation saves an equivalent of 7 man years each year, allowing for increased productivity with the existing team and an improved clean-room cycle-time.

But back to the showroom; I felt like James Bond walking around as Q explains how all the different gadgets work.  Some of Leti’s sensor technologies are used by the art community, as actual mediums for performance art, as well as for security systems in galleries and museums.  Scannell explained the sensor technology used to protect valuable paintings.  I heard him say “If you touch the painting, your arms will blow off. “ WHAT????? Isn’t that a bit drastic? He repeated his statement,  “If you touch the painting, ALARMS will go off.”  OHHHHHH, I was wondering how you could blow off someone’s arms without damaging the painting itself.

On the more practical, for-everyday-use side of technology, Leti has developed an ultra-fast (>5Mbps), close proximity, contactless transmission technology that can be used, for example, as a medical ID card the size and thickness of a credit card, but with embedded components including RF communication technology and memory to store an individual’s insurance information, medical records, and even high definition X-rays. You carry this around with you and have everything the doctor might need right at your fingertips.  Talk about saving on paperwork and time!  The same technology can be used for bio-metric passports and other applications requiring a high level of security. On the perhaps more frivolous side, Leti scientists have developed fibers with OLEDS woven into them.  I can’t wait to see these appear on the next season of Project Runway, as a replacement for sequins as high-fashion sparkle.

While much of the initial work in 3D development was done in a space shared with MEMS development on 200mm wafers, Leti now sports a complete 300mm line for both More than Moore CMOS and 3D integration technologies. Part of the challenge there was maintaining a class 100 “FOUP’d” cleanroom with some processes that might produce unwanted contamination, for example grinding. Thus, precautionary dividers were installed to protect the cleanest processes from the slightly less clean ones.  Much of the tools are now in place, with several more to be delivered by early autumn.  These tools include dielectric deposition tools from Applied Materials, DRIE etch tools from SPTS, Ultratech steppers for lithography, SPTS PVD and SEMITOOL plating tools for TSV metallization and fill processes, EVG bonders for temporary bonding and debonding as well as permanent bonding processes,  a SUSS MicroTec spin coater for RDL, various inspection and metrology tools such as Rudolph, and the latest SET FC300 die bonder customized for clean processes, as part of the latest research for collective die to wafer bonding. Many of these tools are located at Leti as part of a common lab agreement. One example is the recent project with SPTS to optimize barrier and seed seed deposition and also copper pillar technologies, as well as MOCVD for high aspect ratio via’s.

Open 3D Program

One thing is certain, it’s an exciting time here at Leti as 3D processes have become a reality and the institute is ready to offer production using mature technologies as part of the recently established Open-3D program. Indeed, to finally be able to use the term “mature processes” when it comes to 3D integration must feel like an accomplishment in itself.  Scannell explained this novel concept. “Open-3D is about promoting our technologies and giving opportunities to people who don’t have the tools or equipment or integration know-how, to validate their technology. They might have designs, but need to build demonstrators and prototypes.”  He said that initially, there is no transfer of IP or knowhow in Open-3D customer demonstrators. If the customers are happy with the results, they can license the IP, either via a partner foundry or directly. In the case of working with other research organizations, there will be no IP transfer at all, as often the immediate goal is not to ‘industrialize’. One example is the need amongst the research community for enhanced high energy particle detectors. Current detectors surfaces are wire-bonded to an underneath logic circuit, but the wire bonded area leaves a blind spot on the detector surface when trying to tile the detector chips together to create a large detection surface. What is needed is a tilable solution that leaves no blind spots on a large surface area detector. Using 3D technologies that have already been developed at Leti, it is possible to construct such detectors.

Larger companies in aerospace and defense and microelectronics industries have business units that want to test their ideas, and convince the larger organizations that this is the way to go. Open 3D gives them the opportunity to accrue the data needed.  It’s also ideal for customers in need of low volume production, or those serving niche or early markets. The project was launched in April, and according Scannell, has generated more interest than expected, including signed contracts. “We have people interested from as close as to the Swiss border, all the way to Japan” he noted. “Our objective is to get Leti technology known and used and to become the ‘process of records’ leading to license agreements.   Open-3D is a very focused and precise program in terms of technology, we don’t necessarily have the overall 3D global perspective in mind – but if it achieves that in the process so much the better.”