BOOK_CONTENT
From Microsystems Technology: Fabrication, Test & Reliability
Wolfgang Menz,
Institute for Microsystems Technology (IMTEK), Albert-Ludwigs-University Freiburg
Germany
J rgen Mohr,
Institute for Microstructure Technology (IMT), Research Center Karlsruhe,
Germany

1 Overview

The production of microstructures by the LIGA process is schematically represented in Fig. 1 and 2. The essential process steps are X-ray lithography with synchrotron radiation, the electroplating of metals and the molding of plastics. This combination of process steps have been given the name LIGA; LI for X-ray lithography, G for galvanic or electroplating and A for Abformung (German word for molding). In X-ray lithography, as a first step, a plastic layer several hundreds of micrometers thick is applied to a metallic base plate or an isolated plate with an electrically conductive cover layer used as the substrate. The X-ray sensitive plastic is either polymerized in place directly on the base plate or glued to it. Until now PMMA (polymethyl methacrylate) has been used almost exclusively as X-ray resist because of its high contrast known from electron beam lithography. To form the micro structure an absorber pattern of a mask is transferred into the thick plastic layer with the aid of extremely parallel and high intensive synchrotron radiation with a characteristic wavelength between 0.2 and 0.6 nm. The X-ray radiation which passes through the mask is absorbed in the resist and leads to a chemical modification. In the case of PMMA the chemical resistance changes because of bond breaking in the long molecular chain, so that these regions can be dissolved with a...

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Lithography Equipment
Lithography equipment transfers circuit or device patterns onto a substrate using a patterned mask and a beam of light or electrons to selectively expose a photoresist layer. Overlay metrology systems align the pattern masks or reticules.
Imaging Plates
Imaging plates, imaging films and imaging chemicals include offset printer plates, photographic or image setter film, developers, fixers and other supplies for printing, graphics, radiographic and IR imaging.
Radiation Shielding
Radiation shielding is used to block or attenuate the intensity of alpha particles (helium atoms), beta particles (electrons), X-ray radiation, and gamma radiation (energetic electromagnetic radiation).
X-ray Instruments and X-ray Systems
X-ray instruments and X-ray systems use penetrating X-rays or gamma radiation to capture images of the internal structure of a part or finished product.
Nanomaterials
Nanomaterials have features or particle sizes in the range of 1 to 100 nm.

Topics of Interest

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