Spatial Light Modulators

Fraunhofer Institute for Photonic Microsystems

One-Dimensional Spatial Light Modulators on Wafer

Spatial light modulators in the shape of mirror arrays contain a high number of single micro mirrors on a semiconductor chip. The device structure is based on a highly integrated customized electronic circuit (ASIC) which permits an individual analog deflection of any of the micro mirrors.

The Fraunhofer IPMS is engaged in mirror arrays of various mirror quantities and sizes. Depending on the demands of different applications, each mirror can be tilted or lowered individually resulting in a two-dimensional pattern used e. g. in optical projection of predefined structures. High resolution tilt mirror arrays displaying over a million individual 16 × 16 µm² mirrors are applied by our customers in the semiconductor industry as dynamic programmable masks for deep ultraviolet (DUV) optical microlithography. By tilting the mirrors at a frame rate of up to 2 kHz the spatial information is assigned to the photoresist featuring structural dimensions below 130 nm. Further possible applications are the fabrication of printed circuit boards (PCB) as well as semiconductor measurement and inspection. Piston mirror arrays based on 240 × 200 individual mirrors (40 × 40 µm²) permitting mirror deflections of currently up to 530 nm are used for wavefront control in adaptive optical systems. These systems are able to correct e. g. wavefront aberrations in wide spectral ranges in order to improve the image reproduction quality. Furthermore, the device functionalities are particularly sought after in the fields of ophthalmology, astronomy and microscopy as well as spatial and temporal laser beam and pulse shaping.

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