Method of manufacturing a semiconductor device, and semiconductor device manufactured thereby

Abstract

There is described prevention of an increase in the thickness of an oxide film of a silicon wafer, which would otherwise be caused by eruption of gas from a CVD oxide film of another wafer during the course of a high-temperature annealing operation. A semiconductor device, which has a silicon substrate and trench isolation structures for isolating a plurality of active regions from one another, is manufactured by the steps as follows. A first and a second dielectric films are formed on the silicon substrate of one of the conductivity types. The dielectric films are removed from the areas of the silicon substrate where the trench structures are to be formed. The trench structures are formed in the uncovered areas of the silicon substrate to a predetermined depth. An oxide film is deposited into the respective trench structures by means of CVD after the oxide film has been deposited on the interior surface of the respective trench structure. The surface of the deposited oxide film is smoothed by means of removing the deposited oxide film from the silicon substrate through use of chemical-and-mechanical polishing. The second dielectric film is removed and the first dielectric film remains on the areas of the silicon substrate which are to become active regions. Then, the wafer is annealed in inactive gas at a temperature of 900° C. or less.