this invention relates to a novel optoelectronic chip with one or more optoelectronic devices , such as photodiodes , fabricated on a front side of a semiconductor wafer and contacts on a backside of the semiconductor wafer . the backside contacts can be contact bumps , which allow the optoelectronic chip to achieve the benefits of flip chip packaging without flipping the optoelectronic chip upside down with respect to a chip carrier . in an optical communication system , a photodiode chip can be backside bumped to a chip carrier or an electronic chip , allowing front side illumination of the photodiode chip . front side illumination offers many benefits , including improved fiber alignment , reduced manufacturing time , and overall cost reduction .