Fraunhofer IZM-ASSID (All Silicon System Integration Dresden) is a dedicated business unit of Fraunhofer IZM located in Dresden/Moritzburg, Saxony. With its 300 mm wafer-level packaging process line, its mission is to develop custom system integration technologies for industrial partners, with a special focus on 3D architectures. During research and development for such projects, access to well-established processes for prototyping and low-volume manufacturing (according to ISO 9001) can be paramount. RealIZM met with M. Jürgen Wolf, head of Fraunhofer IZM-ASSID to speak about the focus and the past and future of IZM-ASSID.
RealIZM: Please tell us about Fraunhofer IZM-ASSID and its main research topics.
M. Jürgen Wolf: ASSID is a business unit of Fraunhofer IZM. With our technological focus, we are also part and parcel of the “Wafer Level System Integration” (WLSI) department, which I am heading together with Michael Schiffer. This department is mainly concerned with new technologies and applications, related to integration technologies for wafer-level system-in-package designs.
Fraunhofer IZM-ASSID was founded in 2010 to extend IZM’s technology portfolio from the 200 mm to the 300 mm wafer size and to line up with current industrial manufacturing approaches for the implementation of new technologies, especially 3D integration, to satisfy the higher performance requirements and miniaturization needs of new generations of wafer-level packages.
RealIZM: Why did you choose Dresden as the location for this new line?
M. Jürgen Wolf: Our initial intention was to initiate a closer partnership between Fraunhofer IZM and the industry, such as the former Qimonda and AMD, in the field of 300 mm wafer-level packaging. It was also very important for us to establish a 3D integration process line, as this technology has been gaining more and more importance (and still is) and, of course, as we need it to be compatible with 300 mm foundries. The only 300 mm foundries in existence back then were the former AMD site, now GlobalFoundries, and Qimonda/Infineon, both located in Dresden, Saxony. We had a chance to take over a part of the former facilities of Qimonda and, with the funding support of the European Commission, the Free State of Saxony, and the Federal Ministry of Education and Research (BMBF), we established the first and only 3D integration process line (12”/300 mm) in Germany: This is the essence of today’s “All Silicon System Integration Dresden” (ASSID).
RealIZM: 300 mm wafers are a big issue, so what exactly is ASSID specialized in?
M. Jürgen Wolf: 3D integration technology is a very important matter when it comes to satisfying the demand for highly integrated systems in terms of performance and miniaturization. In Berlin, we started our research activities in this field in the WLSI department at an early stage, initially by working on what we call the through-silicon-via (TSV) technology. The first application we developed was a TSV silicon interposer for an industrial client. This was our first successful 3D wafer level integration project. In a next step, Fraunhofer IZM-ASSID developed this TSV technology further into to an integrated 300 mm process not only for interposers, but also for 300 mm active circuit devices. In close cooperation with industrial partners, we defined, realized, and characterized everything, from design to technology and testing.
RealIZM: What is so special about Fraunhofer IZM-ASSID’s strategic orientation?
M. Jürgen Wolf: After the decision to establish Fraunhofer IZM-ASSID in Dresden was made, we transformed the facility into a modern cleanroom complex for 3D wafer-level system integration with all required process modules under my leadership. The required investment was supported by the Free State of Saxony, the BMBF, and the Fraunhofer Society.
It was important for Fraunhofer IZM-ASSID that all technology modules needed for 3D technology were available in a closed line on site. We paid specific attention to make sure that all necessary process modules were designed for development, prototyping, and low-volume manufacturing (LVM) in an industry-compatible manner.
Fraunhofer IZM-ASSID’s technology development always needs to be compatible with industry, so that processes can be transferred and industrial processing services can be provided to our customers. This is one of the most important pillars of ASSID’s strategic and research principles. In our close partnership with the parts of our division still based in Berlin, the Technical University in Dresden, as well as other Fraunhofer institutions like the High Performance Center “Functional Integration for Micro/Nano Electronics” in Saxony, we also investigate and develop new processes and validate new materials.
RealIZM: Why is alignment with the industry so important for ASSID?
M. Jürgen Wolf: At the outset, we recognized the fast pace of development specifically in the microelectronics industry. It became very important for a research institute like Fraunhofer IZM to be able to meet and fulfill the technical requirements of industrial clients. In practice, this means that, first, we can provide immediate solutions for our industrial clients to solve potential issues and, second, our research activities also have an impact on future research requirements and strategy. This is one reason for why Fraunhofer IZM-ASSID is also involved in roadmapping activities on the international level, such as the Heterogeneous Integration Roadmap (HIR). Today’s leading semiconductor foundries worldwide are working on 300 mm wafers. In Germany, more precisely in Dresden, we have three major companies, GlobalFoundries, Infineon, and Bosch, that we are cooperating with.
In several of our projects, we have handled and processed 300 mm wafers from leading international foundries. This is why we placed such great emphasis on making our process line as compatible as humanly possible with foundries like GlobalFoundries, Bosch, Infineon, or other back-end-of-line (BEOL) partners.
With GlobalFoundries in particular, we have achieved compatibility of around 95% for BEOL. This is a good prerequisite for realizing technology developments and transfer processes with industrial partners and for progressing with our research and development work.
RealIZM: How long does the typical development process take for industrial partners?
M. Jürgen Wolf: This depends of course on the complexity of the project, but the philosophy of Fraunhofer IZM-ASSID is to satisfy our customer’s requirements in terms of time and quality and to provide test samples within one year.
RealIZM: How can such a rapid development be achieved?
M. Jürgen Wolf: The most important point is process compatibility. A second important point is that Fraunhofer IZM-ASSID is also offering prototyping and low-volume manufacturing on site. For example, we provide customer services for TSV integration, TSV post processing, or interposers, including bumping and pre-assembly, based on our process of record (POR).
There are also defined technological work packages that Fraunhofer IZM-ASSID offers with qualified service according to the ISO 9001 standards: We have design guidelines in place that describe the technological framework conditions. Based on these, we decide whether we can truly meet the project requirements. We either implement the customer’s requirements in the process, or we adapt our own processes and develop new approaches. That is how Fraunhofer IZM-ASSID has established itself as an R&D service provider, including for prototyping and low-volume manufacturing.
RealIZM: The Wafer-Level System Integration department at Fraunhofer IZM, which includes ASSID, has an ISO-certified management system. How did that come about?
M. Jürgen Wolf: It is because of our relationships with industrial clients that include R&D, prototyping, and LVM. You need ISO 9001 certification for these. Fraunhofer IZM-ASSID was, so to speak, the first division within the Institute to apply for this certification. The original reason was a request from a big industrial customer for whom we had developed a specific TSV technology. At the time, no company in Germany was able to provide this technology. Really, not one. And for this customer, we created and established a qualified processing for devices that are integrated into a new product generation of medical applications. When we carry out something like that, things have to be properly qualified, and that is how the certification came about. A few years later, our Berlin-based counterparts followed successfully in our footsteps.
We have customers for whom we provide process services in long-term contracts, and now more and more customers come and request our services. We keep measuring our knowledge and expertise against international benchmarks. Nothing else counts. Of course, I expect the same from myself as I do from my team at Fraunhofer IZM-ASSID: Measure yourself against the leaders on the international level.
RealIZM: What are your synergies with Fraunhofer IZM in Berlin?
M. Jürgen Wolf: ASSID is an important part of the Fraunhofer IZM. All technologies used at ASSID were developed here, and Berlin takes care of new process developments – this includes close partnerships with material and equipment suppliers. There is a certain synergy in the WLSI department, of course. These processes are geared to be applicable for customers. Our current projects are also touching on topics of other departments at Fraunhofer IZM, such as R3S, SIIT, and ERE. In cases like these, the whole of Fraunhofer IZM’s competences are in play. In my opinion, the synergy with the other IZM departments is very important and could become even stronger in future.
RealIZM: You mentioned synergies in the WLSI department. What kind of opportunities do they offer?
M. Jürgen Wolf: Thematically, there are of course certain synergies. Fraunhofer IZM-ASSID is part of the WLSI department and is working on public and industry projects with the different groups of WLSI. It should be mentioned that the WLSI department brings in the highest industry revenue at IZM, which is an important key parameter for Fraunhofer.
In the recent past, the USeP project was a good example of a successful cooperation. In this project, the cooperation between the IZM colleagues based in Berlin and IZM-ASSID was excellent. There were certain processes in the project that were not compatible with ASSID’s technology line, and these were taken over by colleagues at Fraunhofer IZM in Berlin. Of course, this can also lead to a certain healthy competition, which is also due to our colleagues themselves, who naturally want to get ahead and emphasize their unique selling point.
But we also hand over projects. If, for example, it becomes clear with a customer that the topic matches the portfolio of Fraunhofer IZM in Berlin better, then we naturally pass this on to our colleagues there. There are also certain topics that Fraunhofer IZM-ASSID cannot cover, such as design and simulation, simply because we are more technologically focused. In such cases, we are looking for partnerships inside Fraunhofer.
RealIZM: What would you consider the greatest successes of Fraunhofer IZM-ASSID?
M. Jürgen Wolf: First of all, our general success: We never take on a project with an industry partner that we cannot see through. Our philosophy is that we achieve what we promise to deliver. This has always been the case, and I hope that it will remain this way. Keeping our promises to our partners has become our trademark. Fraunhofer IZM-ASSID with its 40 scientists is known around the world. We can proudly say that important achievements for a world-leading industrial client in Germany were realized at Fraunhofer IZM-ASSID, with qualified sampling according ISO 9001 and with an industrial quality management system. We established very close cooperation with material and equipment suppliers as well as electronic system manufacturers. Some of our current projects are subject to strict confidentiality, so I cannot tell you more about them.
RealIZM: What kind of challenges has Fraunhofer IZM-ASSID faced during the last eleven years, and could you please tell us more about other successes from the past?
M. Jürgen Wolf: The first point was the question whether it is possible to build up a process line with the budget we had. Installing the tools at Fraunhofer IZM-ASSID was a challenge. Putting the new equipment into an existing infrastructure was challenging, but the whole ASSID team worked together very well, from facility management to tool owners.
The second challenge was whether ASSID could work according to the Fraunhofer business model. We underwent a special evaluation, because we are a separate business unit. But by now we can say: we got it. We are working very successfully according to the model. And more than 60% of our budget comes from industrial projects – that is also a success.
Another success is that we have built up a worldwide cooperation network with major companies, equipment suppliers, and scientific institutions and academia in general. We discuss and share up-to-date goals and come up with new innovations and new topics, whether it be quantum computing, high-performance computing, sensor integration, wafer scale integration, or others. I do not like to be excluded from anything. We are keen on projects that look ambitious and are challenging. So, what I want to get across is that Fraunhofer IZM-ASSID has been successful in its technological, scientific, and economic mission for more than eleven years now.
One challenge coming up is that we are at the limit in terms of our existing infrastructure, cleanroom capacity, and office space. There is an increasingly pressing need to expand ASSID’s capabilities. In our conversations with the directors of Fraunhofer IZM and other institutions, we are currently discussing different opportunities to identify potential solutions. One of them is an option to use an expanded cleanroom facility close to Fraunhofer IZM-ASSID and to cooperate with Fraunhofer IPMS/CNT. That also demonstrates that we are constantly looking for potential synergies. But of course, ASSID will remain part of Fraunhofer IZM.
RealIZM: What does the future hold for Fraunhofer IZM-ASSID in the next five to ten years?
M. Jürgen Wolf: We are well-equipped, but we also need more innovations, because technology changes, and there are new demands and requests defined by different applications, such as artificial intelligence, high-performance computing, photonics, or quantum computing. That means it is important to develop a new suitable concept for tool replacements on the one hand, but also new process equipment. We are well-placed to do this within the framework of the European initiative and because of our network. Various funding models are currently under discussion, and a new European venture will start in the next few weeks. We are prepared for it, and we are certain that we will be successful.
There are also other considerations regarding Fraunhofer IZM-ASSID’s future direction, and we are in a discussion with the Fraunhofer HQ and the Ministry of the Free State of Saxony concerning the medium to long-term options with regard to Fraunhofer in Saxony. This might also give ASSID new prospects and opportunities.
In the future, we should also think about how we can use our existing process line in the best and most economical way possible and how we can continue to satisfy our customers’ needs. We are currently working in single shifts, and some processes are automated. That means that we do not shut down our cleanroom after 8 hours; processes run over night, too. But we still have to think about how to meet the demand for flexible working times for processes that normally have to be realized in shift work. Because that’s what our competitors elsewhere in the world are doing.
RealIZM: Do you have any other wishes for the future?
M. Jürgen Wolf: I want to emphasize that it was a good decision of Fraunhofer IZM to establish ASSID in Moritzburg, Saxony, eleven years ago. We fulfilled the requirements of the Fraunhofer business model, and we have established an excellent industrial network worldwide and good connections to academia as well. Furthermore, our customers request our R&D services, and we are an important part in the business chain. Today’s and the future technology in microelectronics demands fast interactions between system design, technology, and characterization, including modeling and simulation. That needs a very good link between scientific staff in different fields and, of course, an excellent alignment and management of complex projects. I believe that Fraunhofer has excellent know-how and the prerequisites to handle this, but it needs a good alignment and more “outside-the-box” thinking. Fraunhofer IZM-ASSID is able to contribute with its technology to exciting achievements in microelectronics today and in the future, and it will make impossible things possible.
Edited by Jacqueline Kamp
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