Patent ID: 7531460

Claim:
A dry etching method for forming trenches having different trench widths in a single crystalline silicon substrate through a mask layer, the method comprising, obtaining data sets which indicate variations of taper angles of trenches for obtaining the data sets as a function of varying parameters; selecting values of parameters based on the data sets for the trenches having the different widths to have substantially identical taper angles; employing an etching apparatus in which the substrate is loaded on either one of a pair of electrodes disposed in an etching chamber and facing each other and high frequency powers are supplied to both of the electrodes to thereby execute plasma etching; wherein the selected values of the parameters include a total flow rate of an etching gas and a high frequency power, introducing the etching gas of the selected total flow rate into the etching chamber; and then etching the substrate by applying the selected high frequency power to an electrode on which the substrate is mounted to thereby controlling the trenches having the different trench widths to have substantially identical taper angles.