Abstract: Various techniques for the fabrication of highly accurate master molds with precisely defined microstructures for use in plastic replication using injection molding, hot embossing, or casting techniques are disclosed herein. Three different fabrication processes used for master mold fabrication are disclosed wherein one of the processes is a combination of the other two processes. In an embodiment of the first process, a two-step electroplating approach is used wherein one of the metals forms the microstructures and the second metal is used as a sacrificial support layer. Following electroplating, the exact height of the microstructures is defined using a chemical mechanical polishing process. In an embodiment of the second process, a modified electroforming process is used for master mold fabrication.