A wide range energy focused ion beam system with post objective lens retarding and accelerating field optics has been developed. This system employs two objective lens elements in tandem. The first objective lens element (OL1) is a conventional einzel lens, the second one (OL2) is a retarding and accelerating mode immersion lens. The post objective lens retarding optics is very effective to obtain a low energy fine focused beam. While the post objective lens acceleration optics is not optically attractive, it has other merits. A very high energy ion beam, mon than 100 keV, can be obtained by relatively small apparatus. It is also possible to change the landing energy without adjustments of ion beam alignment. The optimized deflector system has been designed for the above mentioned optics. Stitching accuracies of the system were evaluated, and the measured stitching errors are 0.115 mu m (2 delta) on the X axis and 0.088 mu m (2 delta) on the Y axis.