An improved mold, for use in the formation of a perpendicular magnetic write head, is described, together with a process for its manufacture. Conventional alumina is replaced by tantalum in the yoke portion of the mold. When both the tantalum and the alumina areas are simultaneously subjected to reactive ion etching, sloping sidewalls are obtained in the alumina area (write pole tip portion) whereas the sidewalls are almost vertical in the tantalum (yoke) area, resulting in a uniform neck height.