As trade tensions continue to flare between China and the United States, China is ramping up investment in its own semiconductor infrastructure to become a self-sufficient player in leading-edge technology. One key area of interest is in MEMS manufacturing, as these devices become more pervasive and critical to emerging application spaces such as 5G, artificial intelligence and automotive electronics—all industries in which China would like to establish leadership.
The global MEMS industry is fast-paced and is highly innovative. While China is investing heavily in building a local MEMS supply chain as part of its Made in China 2025 initiative, it is facing the same manufacturing and equipment challenges that the U.S. and Europe faced decades ago, and it is going to be difficult to catch up, as Europe and the U.S. continue advancing development. In this blog, we examine some of these challenges and offer suggestions for overcoming these hurdles.
Understand the Difference Between CMOS and MEMS
While CMOS and MEMS manufacturing processes are related, there are differences between them that impacts the industries infrastructure. First of all, MEMS and CMOS features are fundamentally different: MEMS are three-dimensional devices with moving parts, and CMOS are two-dimensional.
CMOS devices are built layer by layer, on top of silicon. While etch and deposition are standard processes, they primarily use lithography and plasma etching to create patterns on the die. MEMS, on the other hand, are built either into the silicon or onto the silicon, i.e. bulk or surface micro-machined MEMS. Deep reactive ion etching of bulk MEMS—also known as the Bosch process, because it was developed by Bosch in the 1990s—is one of the oldest process solutions designed specifically for MEMS.
Therefore, while many etch and deposition processes are similar, certain ones are unique to MEMS, as are their failure mechanisms. For example, because CMOS devices have no moving parts, there is no need for what is known as the release process. This is the process of releasing the device from its anchor to create a fully free-standing 3D moving device. Because of that, stiction—when the moving part ’sticks’ to the surface, causing device failure—isn’t a CMOS concern.
Additionally, MEMS are application specific, and this impacts the volumes of each device. So MEMS devices are unlikely to reach the same volumes as CMOS devices. One device is not enough to make a MEMS manufacturing line profitable, because they won’t require 50K wafer starts. Even MEMS microphones, an application that has hit high volumes, are spread out between multiple players.
Learn from the US and Europe
MEMS foundries exist and are successful because they manufacture many different MEMS products for many different companies. For example, Bosch, in Germany, manufactures not only Bosch-designed MEMS, but has also created an internal market to supply to its subsidiary companies. ST Microelectronics has also succeeded in using a foundry model.
Even though Europe and the U.S. have been driving MEMS innovation for years, up until recently, nobody built a fab dedicated to MEMS. While some companies had a MEMS process line, they were not necessarily state-of-the-art. Rather, it was a way to repurpose older semiconductor fabs, and breathe new life into them. Converting spare capacity in older CMOS semiconductor manufacturing facilities to MEMS production lines has proven to be a successful approach.
Choose the Right Path
To succeed as a Chinese MEMS company, the decision to outsource or build a fab depends on your business model. MEMS integrated device manufacturers don’t really exist. In the US and Europe, MEMS design companies generally outsource manufacturing to either dedicated MEMS foundries that have multiple MEMS offerings, and are able to handle different wafer sizes, as well as a variety of materials and processes. Alternatively, several top-tier semiconductor fabs also offer MEMS manufacturing services.
In reality, unless you are going to be a foundry serving multiple MEMS companies, it doesn’t make sense to build your own fab. An alternative to outsourcing offshore for the internal Chinese MEMS market would be a collaborative model, where several MEMS companies share a fab. Ultimately, the choice is whatever gives the best return on investment.
Collaborate with memsstar
At memsstar, we focus on technology, manufacturability and yield. By achieving these goals, we ensure that our customers are capable of manufacturing the most advanced MEMS devices at the lowest cost, now and in the future.
If you choose to invest in a shared fab, we can provide a full range of equipment that provides a true path from R&D to production. Our MEMS offering combines a blend of next-generation proprietary release etch and coatings technologies, and proprietary as well as repurposed semiconductor equipment. This range of offerings ensures we can offer a full suite of etch and deposition solutions to enable MEMS development and production-ready manufacturing. Contact us to learn more.
