The products resulting from the partnership are a silicon microphone, micro probes for analysis and two pressure sensors, one for pump controls and another for fluid power systems. By sharing equipment, premises and know-how, the participants of the project - the Micro and Nanotechnology Research Centre (MIC), the testing institute Delta, and the companies Capres, Danfoss, Grundfos and SonionMEMS - have created a fertile environment for the development of MEMS in the Øresund Region.

The project, called SUM (Collaboration on Development of Microsystems), has a total budget of approximately 4.7 million euro. It has also led to the establishment of a packaging facility called PackLab at the Technical University of Denmark (DTU). Entirely dedicated to packaging of Microsystems for industrial use, PackLab is a 10,000-class clean room with specialized workplaces of class 100 (equivalent to a clean room within the chip industry).

Pressure sensor

Before the cooperation in the SUM project, Grundfos had a sensor project on a research level and six employees. Today the company has 22 employees and a production line for manufacturing sensors in clean room facilities located in Farum, north of Copenhagen, that the company rents from Ibsen Photonics. Grundfos has already started to produce a pressure sensor that is one of the products resulted from the SUM project.

The product should meet the demand that exists for low cost differential pressure sensors for wet/wet applications with high reliability and long lifetime. Traditional pressure sensors are the size of a box of matches but the ones to be produced by Grundfos are even smaller: four times four millimetres. With its new technology, Grundfos itself will produce the silicon wafers used in the sensors.

The smallest microphone

SonionMEMS is building its own clean room facilities in Roskilde, Greater Copenhagen, for the production of the company's silicon microphone. The new 300 square-metre facilities are expected to be complete in the beginning of 2003 and the production should start in 2004.

SonionMEMS claims that it will produce not only the world's smallest microphone, with its volume below 3 cubic metres, but also a device that is competitive on most important performance parameters. The minute microphone can be a component of mobile phones, hearing instruments and headsets. Integrated circuits designed in-house will be used in the production of the microphone.

Silicon microphones are an area in which the technology is still at an early stage. In such devices, the traditional microphone diaphragm is made from a thin silicon membrane. Silicon microphones can add value to a range of applications such as high-quality headsets, voice-activated systems and eventually also particularly demanding applications within mobile terminals.

Probes and needle

Within the shared packaging laboratory of SUM, Capres has worked with prototype packaging for microscopic four-point probes. The company has developed a mounting procedure for these probes, which has led to a new probe packaging standard. The probes are designed for micro-scale electrical characterizations of materials, for quality control in the semiconductor and thin-film industries and in research activities.

Danfoss’ participation in the project was aimed at producing a needle sensor to be used in fluid power and refrigeration applications. The needle sensor should enable extreme miniaturisation for high-pressure sensing and flexible integration in fluid power systems.

During the SUM project, MIC has developed a prototyping process for fabrication of MEMS-based sensors with piezo resistive readout such as pressure sensors, accelerometers and bio-chemical microsystems.

Delta’s participation in the project was aimed researching and developing packaging and testing of MEMS, which amount to 60-80 per cent of production costs. As a result of the cooperation, Delta has developed new packaging and test services specifically for MEMS products.

Less visible results

Although the products to be mass-produced are its most visible results, the SUM project has also led to other important effects. It has been responsible, for example, for training 40 employees in the area of MEMS.

The SUM project is based on a so-called centre contract (centerkontrakt), which is an agreement among partners from universities, knowledge centres and private companies interested in developing new technologies for broad use in industry.

December 2002