MEMS Background

Due to the explosive growth of the semiconductor industry, various processing techniques for working with silicon (Si) as a substrate material have been developed and successfully established by the semiconductor industries.

Now Si is being used for producing small-scale mechanical components of the size of only a few microns (10-6m) or even less. The processing techniques are being adopted from the semiconductor processes and further developed for the means of achieving small and reliable structures. The possible applications for such micromechanical devices are countless, and are already being used by the aerospace and automotive industries for pressure sensors and accelerometers. With improvements in processes that allow cheaper mass production of the structures, micromachined components will get more and more important, possibly resulting in a technical revolution when formerly impossible structures can come possible.

Figure 1: Example for a micromachined gear for the conversion of rotational motion to linear motion15

With the means of microengineering the following aims can be achieved:

A new approach in this field consists in combining highly integrated electronic and mechanical parts together, resulting in so called "Microelectromechanical Systems" (MEMS). This is the next logical step in this process of development and offers a variety of new products.

The most cost-effective way for producing MEMS structures would be to do the processing for the semiconductor (active) part and the micromechanical part on the very same wafer without the need of later assembling of different parts produced separately. Not many experiments in this sector have been made so far and it is to prove whether the IC process and the one used for the mechanical parts are compatible to each other in each case. This report's aim is to provide detailed information on the steps of the production of mechanical structures used for the assembly of high frequency circuits that can possibly be combined with active parts on the same wafer.