Method for fabricating a semiconductor device using a BPSG layer containing high concentrations of phosphorus and boron

Claim 1

A method for forming a smooth borophospholisilicate glass film on a semiconductor substrate, the method comprising the steps of: (a) providing a semiconductor substrate having at least one stepped portion thereon; (b) forming on one side of the substrate a borophosphosilicate glass layer having a boron content of about 2 to 5 wt % and a phosphorus content of about from 5 to 8 wt % provided that the total content of the boron and phosphorus is in the range of from 7 to 10 wt %; and (c) subjecting the layer to thermal treatment under conditions of a temperature of not lower than 940° C. and a time of not shorter than 15 minutes in an atmospheric gas supplied at flow rate of not lower than 19 liters/minute whereby the silicate glass layer is smoothed on the surface thereof without formation of undesirable grains on the surface.

Claim 2

A method for forming a smooth borophospholisilicate glass film on a semiconductor substrate, the method comprising the steps of: (a) providing a semiconductor substrate having at least one stepped portion thereon; (b) forming on one side of the substrate a borophosphosilicate glass layer having a boron content of about 2 to 5 wt % and a phosphorus content of about from 5 to 8 wt % provided that the total content of the boron and phosphorus is in the range of from 7 to 10 wt %; and (c) subjecting the layer to thermal treatment under conditions of a temperature of not lower than 940° C. and a time of not shorter than 15 minutes in an atmospheric gas supplied at flow rate of not lower than 19 liters/minute whereby the silicate glass layer is smoothed on the surface thereof without formation of undesirable grains on the surface.

Claim 7

A method for fabricating a semiconductor device including an insulating borophosphosilicate glass layer, the method comprising the steps of: (a) providing a semiconductor substrate having an element region and a separation region thereon by formation of a thermally oxidized SiO 2 film; (b) forming a gate insulating film on the element region; (c) forming a first conductive layer over the construction obtained in the above step; (d) removing the first conductive layer and the gate insulating layer selectively to expose part of the substrate; (e) forming a diffusion layer on the exposed portions of the semiconductor substrate; (f) forming, over the entire surface of the substrate obtained the above step, a borophosphosilicate glass layer which contains about 2 to 5 wt % of boron and about 5 to 8 wt % of phosphorus provided that the total content is in the range of from 7 to 10 wt %; (g) subjecting the substrate to thermal treatment at a temperature of not lower than 940° C. format least 15 minutes in an atmospheric gas supplied at a flow rate of not lower than 19 liters/minute so that the borophosphosilicate glass layer becomes smooth on the surface thereof without formation of undesirable grains on the surface; (h) forming an opening in the smooth borophosphosilicate layer; and (i) forming a second conductive layer on a region including the opening.

Claim 8

A method for fabricating a semiconductor device including an insulating borophosphosilicate glass layer, the method comprising the steps of: (a) providing a semiconductor substrate having an element region and a separation region thereon by formation of a thermally oxidized SiO 2 film; (b) forming a gate insulating film on the element region; (c) forming a first conductive layer over the construction obtained in the above step; (d) removing the first conductive layer and the gate insulating layer selectively to expose part of the substrate; (e) forming a diffusion layer on the exposed portions of the semiconductor substrate; (f) forming, over the entire surface of the substrate obtained the above step, a borophosphosilicate glass layer which contains about 2 to 5 wt % of boron and about 5 to 8 wt % of phosphorus provided that the total content is in the range of from 7 to 10 wt %; (g) subjecting the substrate to thermal treatment at a temperature of not lower than 940° C. format least 15 minutes in an atmospheric gas supplied at a flow rate of not lower than 19 liters/minute so that the borophosphosilicate glass layer becomes smooth on the surface thereof without formation of undesirable grains on the surface; (h) forming an opening in the smooth borophosphosilicate layer; and (i) forming a second conductive layer on a region including the opening.