Abstract: Bottom chassis for a tablet-type mobile display having a thickness of 0.2 mm, light weight and high strength by controlling the alloy composition and process condition. A method for manufacturing the bottom chassis comprises: (a) homogenizing a slab material by heating, the slab material having at most 0.3 wt % silicone, at most 0.4 wt % iron, at most 0.1 wt % copper, 0.15˜0.2 wt % manganese, 2.5˜3.5 wt % magnesium, 0.15˜0.35 wt % chromium, and at most 0.1 wt % zinc, the balance being impurities and aluminum; (b) subjecting the homogenized material to hot-rolling to thickness of 7.5±0.5 mm followed by cooling; (c) subjecting the hot-rolled and cooled material to a 1st cold-rolling to thickness of 2.5±0.5 mm followed by annealing; (d) subjecting the cold-rolled and annealed material to a finishing cold-rolling to thickness of 0.2±0.05 mm; (e) tempering the finishing cold-rolled material; and (f) processing the tempered material to the final shape.