Abstract: A method of reflowing a semiconductor device to increase the planarization thereof includes the steps of first forming a first insulating layer over a silicon semiconductor substrate, forming at least one electrode over the first insulating layer, and then forming a second insulating layer over the at least one electrode and the first insulating layer. A first borophospho silicate glass (BPSG) layer of low concentration is then formed over the resultant surface to a thickness of 6000 to 9000 .ANG. and containing 3-4 wt. % boron and 5-7 wt. % phosphorous. A second borophospho silicate glass (BPSG) layer of high concentration is formed over the resultant surface of the first borophospho silicate glass (BPSG) layer to a thickness of 2000 to 6000 .ANG. and containing 4-7 wt. % boron and 8-10 wt. % phosphorous.