Methods for dry etching at low substrate temperatures using gas chemistry including a fluorocarbon gas and a gas including oxygen

A method for fabricating a semiconductor device, the method comprising:

• forming a gate electrode on a semiconductor substrate;
• forming diffusion layers in source/drain regions of the semiconductor substrate;
• forming a metal silicide film on the gate electrode and the diffusion layers of source/drain regions;
• forming a silicon oxide film on the metal silicide film;
• and
• dry-etching the silicon oxide film to form in the silicon oxide film a first contact hole located over the gate electrode, and second contact holes located over the diffusing layers in the source/drain regions,
• wherein etching gas used for the dry-etching is gas including a single fluorocarbon gas and at least one of O2 gas and O3 gas,
• the dry-etching is conducted in a single step etching process, and
• the temperature of the semiconductor substrate is 30° C. or lower when the dry-etching is conducted.

A method for fabricating a semiconductor device, the method comprising:

• forming a dielectric film on a base comprising at least one material selected from the group of a metal silicide and Si;
• and
• dry-etching the dielectric film to form in the dielectric film first and second contact holes that expose surfaces of the base;
• wherein a depth of etching to form the first contact hole is less than a depth of etching to form the second contact hole;
• wherein the etching gas used for the dry-etching is gas including a single fluorocarbon gas, an inert gas, and a gas containing oxygen;
• wherein the dry-etching is conducted using a single step in which a flow rate of the single fluorocarbon gas, a flow rate of the inert gas, and a flow rate of the gas containing oxygen are not changed during the dry-etching, and
• wherein the temperature of the base is 30° C. or lower when the dry-etching is conducted.