Foundry for MEMS technology incorporating thin-film piezoelectric elements

August 28, 2014 // By Graham Prophet
Rohm Semiconductor has established a process for MEMS (Micro Electro Mechanical Systems) using thin-film piezoelectric elements, and implemented the first foundry business that integrates product design and manufacturing processes, from wafer pulling to mounting; the operation will supply sensors and actuators with, “breakthrough energy savings and miniaturisation”.

Piezoelectric elements are incorporated into a wide variety of electronic devices, from conventional inkjet printheads to autofocus systems in infrared and standard cameras. Combining these elements with MEMS technology, which is commonly used in accelerometers and gyroscopes, makes it possible to simplify design and reduce the size of processing controllers, contributing to increased performance, lower costs, and greater end-product miniaturisation. In addition, the energy-saving characteristics of the piezoelectric element itself, which requires very little power during standby, are garnering increased attention – particularly in the sensor market where explosive growth is expected.

Rohm has begun conducting joint development of piezoelectric MEMS products and is gradually expanding production lines to accommodate growth markets, such as industrial inkjet printers, sensors, and wearable devices.

In the process of building piezoelectric MEMS, Rohm says, deposition of the thin-films that possess high piezoelectric properties, and precision fabrication and moulding of micro-piezoelectric elements, are difficult to realize. High-precision processing is required for the MEMS drive block, and additional knowledge and expertise – along with the cultivation of new technologies – are needed in order to support next-generation applications and emerging markets.

In response to these challenges, Rohm is actively engaged in the research into thin-film piezoelectric elements. Based on the findings of Professor Isaku Kanno of the Graduate School of Engineering at Kobe University on evaluation measurement methods for thin-film piezoelectric elements, and by taking drawing on the Rohm Group, which includes Rohm's ferroelectric technology developed for long-term memory, Lapis Semiconductor's high-sensitivity MEMS/mounting technology, and Kionix's MEMS miniaturisation technology, the company has established a manufacturing process at Lapis Semiconductor Miyazaki that can build piezoelectric MEMS optimised for a variety of markets and applications.

Rohm's MEMS processes using thin-film piezo elements makes use of several differentiators:

1. An integrated production system, from wafer pulling to mounting, enables complete control of product manufacturing for unsurpassed quality and flexibility

2. 1500 m2 clean room built for specifically for IC