Methods of forming oxide-filled trenches in substrates using multiple-temperature oxide deposition techniques

Abstract

Methods of forming integrated circuit substrates include forming first and second trenches having unequal widths in a semiconductor substrate and then depositing a first oxide layer at a first temperature into the first and second trenches. The first oxide layer has a thickness sufficient to completely fill the first trench but only partially fill the second trench, which is wider than the first trench. A step is also performed to selectively remove a portion of the first oxide layer from a bottom of the second trench. A second oxide layer is then deposited at a second temperature onto the bottom of the second trench. The second temperature is greater than the first temperature. For example, the first temperature may be in a range from about 300° C. to about 460° C. and the second temperature may be in a range from about 500° C. to about 600° C.