M-Press Systems (M) Sdn. Bhd.
Industrial Microwave-, Plasma-, RF- and Control-Systems

Mems Production

MEMS (MicroElectroMechanicalSystems) are sub-millimeter devices made from components with a size ranging from 1 micrometer (0.001 millimeter) to 100 micrometer (0.1 millimeter). Because devices of this size could not be manufactured by means of conventional machining processes, they were first manufactured in a process similar to the manufacturing of semiconductor devices, i.e. by means of material deposition, photo-lithography and finally etching. While at the beginning MEMS were mainly made from silicon, nowadays other materials are also used, e.g. ceramics, metals and polymers, using additional processes which can differ from those used by the semiconductor industry.

Nowadays MEMS can be found in a broad range of products and applications, some typical examples are:

MEMS production via LIGA process

The LIGA process ("Lithographie, Galvanoformung, Abformung", German for Lithography, Electroplating, and Moulding) enables the fast, reliable and cost-efficient manufacturing of MEMS structures or components made from metals. It permits the production of parts with a final thickness ranging from approximately 1 micrometer to several millimetres, while maintaining aspect ratios of 100:1 and side flank angles of up to 89.95 e when X-ray exposure is used. When omitting the optional replication step, manufacturing parts with the LIGA process takes place in 4 steps:

Exposure

An electrically conductive substrate is coated with an even layer of a photoresist, usually SU-8, KMPR or PMMA, and covered with a mask, which determines the final shape of the product. The whole stack is now exposed to high energy photons to transfer the shape from the mask into the photoresist. Depending on the thickness of the photoresist layer, allowable aspect ratio etc. either a simple UV lamp or a highly collimated X-Ray source is used.

Development

Afterwards the substrate together with the photoresist is flushed with a suitable developer solution, which dissolves the unexposed photoresist and leaves the cavities for the next production step.

Electroplating

After cleaning the substrate and remaining photoresist, the cavities left in the photoresist layer are filled with metal by means of a electroplating process.

Stripping

After the metal is deposited the remaining photoresist needs to be stripped. Formerly this was either done by flood-exposure and developing of the remaining photoresist or via chemical stripping with solvents. However, because both of these alternatives are very time consuming, stripping via reactive ion etching is preferred nowadays, please see below.

Photoresist stripping via reactive ion etching

Because the final stripping process using flood-exposure or chemical stripping adds considerable time to the complete manufacturing process, stripping via reactive ion etching is now the preferred way of stripping as it offers the following advantages:

We are supplying separate reactive ion sources as well as complete reactive ion applicators, if you have any requirements please contact us.