A resist process has been defined, characterized and optimized using Shipley UVN2 chemically amplified negative resist for the fabrication of x-ray membrane masks using electron-beam lithography. Advanced masks require precise control of 150 nm critical dimensions with test features of 100 and 125 nm. UVN2, a chemically amplified negative resist designed for DUV processes, also functions as an electron- beam resist wit sensitivities of 10 to 20 (mu) C/cm2 depending upon the bake parameters. This paper discusses the process and demonstrates the capability of the resist on membrane masks. Post-apply bake (PAB) and post-expose (PEB) affect the resist sensitivity and process latitude of UVN2. The resists process was defined by using a statistically designed experiment to optimize the PAB and PEB conditions. The figures of merit included resist sensitivity, dose latitude, resist thinning and resolution. Once the patterning process was defined, the etch processes and optimized, features as small as 100 nm have been successfully transferred from the UVN2 resist into the tantalum-silicon membrane with critical-dimension uniformity of less than 15nm 3(sigma) within a mask. The process latitude, resolution, and excellent CD uniformity result obtained for UVN2 resist are consistent with the manufacturing requirements for the fabrication of x-ray membrane masks.