A new x-ray microlithography exposure system has been designed and built at the Center for Advanced Microstructures and Devices (CAMD) to meet the specific demands of synchrotron radiation assisted processing for microfabrication and high aspect ratio micromachining. The system consists of a broadband transmission (1.2-6.5 Angstrom) beamline and a multichamber x-ray exposure station which can simultaneously provide x-ray exposure and activation, plasma, or reactive ion etching (RIE). The beamline is operational at the CAMD 1.3-1.5 GeV synchrotron storage ring. The x-ray exposure station includes filter and exposure chambers. A filter chamber is incorporated into the exposure system to optimize the radiation spectra for thick resist (in excess of 1 mm) exposures and to protect the Be window from reactive gases during exposure. Two assisting agents, x-ray irradiation and rf (13.53 MHz) induced plasma for RIE, can be used separately or in combination. Samples of similar to 500-mu m-thick PMMA resist have been exposed in neutral and reactive atmospheres and successfully developed. The preliminary results indicate that He gas acts as a "catalyst" for PMMA losses during exposure.