We employ UV photolithographic and electron beam lithographic patterning of diamond seeding layer on SiO2/Si substrates for the selective growth of micrometer and sub-micrometer diamond patterns. Using bottom-up strategy, thin diamond channels (470 nm in width) are directly grown. Differences between wet chemical and plasma treatment on the patterned diamond growth are studied. We find that the density of parasitic diamond crystals (outside predefined patterns) is lowered for gas mixture CF4/O2 plasma than for rich O2 plasma. After CF4/O2 plasma treatment, the density of parasitic crystals is 106 cm-2 which is comparable to the wet chemical treatment. Introducing sandwich-like structure, i.e. photoresist-seeding layer-photoresist, and its treatment (lift-off and CF4/O2 plasma) further reduces the density of parasitic crystals down to 105 cm-2. The advantage of this novel treatment is short processing time, simplicity, and minimal damage of the substrate surface.