By Rachel Robinson
WaferNews Associate Editor
In recent months a trend has hit the semiconductor industry – and it has nothing to do with the economy or the downturn. While a few companies have earned money testing MicroElectroMechanical Systems (MEMS), it is a fairly new niche that is beginning to play host to companies throughout the chip industry.
MEMS have become a hot topic recently due to the growing potential market for them, according to Leif Madsen, manager of the MicroTest project for DELTA Danish Electronics, Light & Acoustics, Copenhagen, Denmark.
Claus Dietrich, international product manager of probe systems at Karl Suss, Munich, Germany, agreed, adding, “During the last few years, MEMS has seen a lot of development of new devices, and it is now in the phase of becoming a mass production product, driving the medical, automotive, and telecom industries.”
Recently, two collaborations have been announced in as many weeks, both designed to test MEMS at the wafer level. Karl Suss will work with DELTA to develop new methods and equipment for testing MEMS at the wafer level with non-electrical stimuli and detection, and Peabody, MA-based Etec Inc. and Umech Technologies, Watertown, MA, have announced a joint product agreement to develop next-generation MEMS test systems.
In the past, many MEMS companies tested their own products in-house, Art Holzknecht, VP of sales and marketing at Etec, told WaferNews. Recently, that has changed. “If you look at the semiconductor industry, you don’t see people making their own test equipment. The same thing has begun to happen with MEMS,” noted Holzknecht.
Dietrich agreed with Holzknecht’s assessment. “It’s expensive and time consuming to develop your own test equipment.”
Testing MEMS is tricky because it is not measuring currents and voltage, Dietrich told WaferNews. For MEMS, Dietrich said, you have to apply non-electrical signals, such as air pressure, acceleration, mechanical force, gas, light, and sound. “It is feeding the sensors with non-electrical signals that is the problem,” he said.
Testing MEMS on the wafer level is imperative, Holzknecht said. MEMS are an expensive technology – mostly due to packaging and testing, which encompass 60 to 80% of the device cost. “The last thing you want to do is package a bad die,” Holzknecht said.
“The new idea, or philosophy, is to provide a test service on the wafer level, on an unpackaged, not-finished device,” Dietrich said. In the development of new technology, he said, you need feedback as soon as possible. Additionally, many of these components will become a part of a more complex device. “You want to make sure that the marriage doesn’t fail,” he explained.
While MEMS devices are starting to come to the forefront of the industry, uses are still fairly limited. In the medical industry, MEMS are used in microphones for hearing aids, disposable blood pressure devices, etc. In the automotive industry, some uses include airbag sensors, and tire pressure sensors (WaferNews 8.32, 12 August 01). MEMS are also used in photonics as well.
“The MEMS industry is looking for critical mass. The photonics market has helped that tremendously,” said Holzknecht. “For other than pressure MEMS, wide-scale implantation of MEMS has been limited. Here is a technology that is looking for applications.”