Matthias Nienhaus

Design and realization of a penny-shaped micromotor

For many applications in rapid growing markets of microproducts, e.g. miniaturized hard disk drives in personal computers, mobile optical scanners, or for the market of consumer electronics, a novel, penny-shaped micromotor was developed at IMM. Designed to provide an output torque of more than 100 (mu) Nm, the permanent magnet motor shows a diameter of 12.8 mm and a height of 1.4mm. Besides the maximum torque and the ultra-flat shape, one further essential design parameter was a construction that allows an easy assembly and is suitable for mass-production. An important contribution to mass production philosophy is the intensive use of microfabrication technologies especially for both, the production of the permanent magnet rings by micro molding and micro compressing techniques and the micro coils by the way of photolithographic batch processes.

Automatic microassembly of radar sensors for automotive applications

For the assembly of miniaturized radar distance sensors vacuum gripers for handling touch sensitive and very small millimeter wave monolithic integrated circuits (M3ICs) have been developed. The grippers are designed modularly to allow different combinations of gripper heads, chip-specific gripper plates and gripper exchange interfaces. The manufacture of the gripper components by (mu) -EDM and the batch processing of photoetchable glass is presented. In addition, a solution for the removal of M3ICs from adhesive carriers, such as VR Gel-Paks and bluetape with vacuum support has been developed which is suitable for automatic pick & place machine routines.

Miniaturized objective lens for a photoelectron emission microscope

Photoemission electron microscopy (PEEM) has turned out to be one of the most promising methods for surface analysis in the recent years. It is a full field imaging technique based on the emission of secondary electrons by far ultraviolet light or X-rays. The emission intensity of secondary electrons is critically dependent upon the acceptance angle of the incident radiation. However, the size of the microscope restricts this angle substantially. Miniaturizing the objective lens of the microscope reduces the restriction of the acceptance angle and improves the performance of the PEEM considerably. We report on the fabrication of a miniaturized objective lens containing the extraction electrode, the electron column, the contrast aperture and the electron optical correction system for a PEEM. The extraction electrode as well as the electron column have been manufactured using precision milling techniques and electron discharge micromachining. For the fabrication of the correction system (stigmator / bending unit), a process combining aligned photolithography into a thick SU-8 resist and electroforming has been used. All electrodes were made in gold with a height of 150 (mu) m. After attaching a FOTURAN substrate to the electrode and etching under the electrodes, free standing apertures in an octupole and quadruple arrangement were obtained. The outer diameter of the electrodes is 5 mm and the inner diameter is 1 mm, respectively. Each electrode is connect individually to the external power supply which controls their operation. The overall size of the miniaturized objective lens is 23 mm, which has reduced the size of the lens by one order of magnitude when compared to commercially available instruments.