This paper reports the development of the first, within our knowledge, all-electric pneumatic-less miniature vacuum mechanical roughing pump that operates in atmosphere and creates a sub-atmospheric absolute pressure down to a few 100's torr. The developed vacuum pump achieves high force and large deflection actuation that is critically needed for efficient vacuum generation, by utilizing large-force electromagnetic actuation and hydraulic micro-spot focusing, as well as a large-deflection latex polymer as a membrane material. The fabricated vacuum pump sequentially actuated multiple pump membranes in an actuation force of >616mN over a distance of >2mm; and achieved an absolute pressure of 424 torr (212 torr differential pressure from atmosphere) by evacuating a chamber volume of 1ml in 7 minutes. It operated at a frequency of 1Hz, consumed 3.6W of power, and its packaged dimension was 18×27×5.5mm3.