MEMS treads logic road
Across the industry, it is becoming more and more evident that the MEMS sector will follow a similar path to CMOS logic. That path is one in which integrated device manufacturers (IDMs) that do everything thing under one roof will progressively give way to those choosing one side or other of a dual fabless-foundry business model, where there are those that specialise in manufacturing in volume and those that specialise in design.
The difference between MEMS and logic, and the reason previously given for the continued supremacy of the IDM in the MEMS domain, is that in the case of MEMS the manufacturing process is fundamentally linked to the design possibilities. In contrast, over 30 years of digital CMOS development has led to a remarkable consensus on the best ways to implement ICs and a degree of separation of design from process implementation. The fabless avoid manufacturing infrastructure costs while those that incur them spend big for economies of scale and then manufacture for many customers and do not compete with them.
In CMOS logic this has led to the rise of such companies as the foundry Taiwan Semiconductor Manufacturing Co. Ltd (TSMC) and fabless chip companies such as Qualcomm, Broadcom and Mediatek. It is also notable the way a traditional IDM Advanced Micro Devices evolved to become fabless and threw off its manufacturing operations, which led to the creation of GlobalFoundries.
Meanwhile the latest MEMS status report from Yole Developpement indicates the start of similar process. It remains true that there almost as many detailed MEMS processes and packages as there are MEMS products but the volume is met by a much-reduced set for such things as inertial sensors, for pressure sensors, for microphones.
The Yole status report showed that some of the former leaders in MEMS, the likes of Texas Instruments (digital light processing) and Hewlett Packard (microfluidics for inkjets) are seeing sales decline. STMicroelectronics, the MEMS market leader in 2012, which operates a split strategy where is does MEMS manufacturing some customers and also produces under its own name, has also come under pressure. Meanwhile, Yole is tipping InvenSense and mCube as rising stars of the MEMS firmament.
Both companies have intimate knowledge of the manufacturing processes relevant to their designs but they have avoided the cost of setting up their own wafer fabs and worked with TSMC.
It is a financial formula that works. The fabless get a faster, lower-cost route to market that helps them compete against the IDMs while the foundries acquire process know how, which they may one-day be able to offer to other MEMS startups. Although the true standardisation of manufacturing processes has yet to happen in the MEMS sector, it appears the economic benefits of disaggregation into a fabless and foundry duality will not be denied.
Of course, these things are never simply black and white. In logic production IDMs have co-existed with foundries for many decades. In last few years the interdependence of design and process has increased, as have the variety of processes (planar CMOS, FinFET CMOS, FDSOI and other variants). Similarly in the MEMS domain ST's replacement at the top of the MEMS vendor ranking is Robert Bosch, which is a classical IDM with its own dedicated MEMS wafer fab.
Nonetheless, expect future MEMS startups to be predominantly fabless. They will be looking for foundries to work with them on process development and carry the cost of expensive wafer processing machines and the likes of TSMC and GlobalFoundries appear ready to step forward to do that. IDMs such as Bosch and STMicroelectronics will also be tempted to keep wafer fabs full by running third-party MEMS wafers that brings them into the part-time foundry category.
This financial slope led to the foundry business solution in digital logic and it will do the same for MEMS and it probably won't take decades to do it.
- Peter Clarke
EE Times Europe
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