Abstract: The present invention provides a method of forming an undoped silicate glass layer on a semiconductor wafer by performing a high density plasma chemical vapor deposition process. The semiconductor wafer being positioned in a deposition chamber. The method comprises forming the undoped silicate glass layer by performing the high density plasma chemical vapor deposition process in the deposition chamber under the following conditions: an argon (Ar) flow rate of 40 to 70 sccm (standard cubic centimeter per minute); an oxygen (O.sub.2) flow rate of 90 to 120 sccm; a silane flow rate of 70 to 100 sccm; a gas pressure of 3 to 10 mtorr; a temperature of 300 to 400.degree. C.; and a low frequency power of 2500 to 3500 watts. Wherein the ratio of Ar to O.sub.2 is 0.53, and O.sub.2 to silane is 1.23.