We describe a complete development process of a segmented-blade linear ion trap. An alumina substrate is characterized with an x-ray diffraction and loss-tangent measurement. The blade is laser-micromachined and polished, followed by sputtering and gold electroplating. Surface roughness is examined at each step of the fabrication via both electron and optical microscopies. On the gold-plated facet, we obtain a height deviation of tens of nanometers in the vicinity of the ion position. Trapping of laser-cooled 174Yb+ ions is demonstrated.