Manufacturing method of semiconductor device

Abstract

A breakdown voltage of a capacitive element is improved by re-crystallizing a tungsten silicide film under a dielectric film. In forming the capacitive element which uses a polycrystalline silicon film and the tungsten silicide film as a lower electrode, the tungsten silicide film is re-crystallized by heating using an RTA (Rapid Thermal Annealing) system before forming a silicon oxide film used as the dielectric film. By doing so, an interface between the silicon oxide film and the tungsten silicide film is prevented from becoming uneven and a breakdown voltage of the dielectric film is improved drastically. Thus an amount of electric charge stored in the capacitive element is increased as well as it is made possible that the capacitive element is applied to a semiconductor device operating at higher voltage.

Description

technical field [0001] The present invention relates to a technique useful for improving the characteristics of a capacitive film in a method of manufacturing a semiconductor device having a capacitive element. Background technique [0002] In order to form a capacitive element in a semiconductor device, there is a method in which a lower electrode has the same structure as a gate electrode, and a capacitive element is formed by forming a capacitive film and an upper electrode thereon. In this manufacturing method, the structure of the lower electrode is often made into a polyside structure in which a polysilicon film and a tungsten silicide film are stacked. [0003] A capacitive film made of an insulating material is formed on the lower electrode, and an upper electrode made of a polysilicon film is formed on the capacitive film. In this method, since the structure of the lower electrode is the same as that of the gate electrode, there is an advantage that the lower elect...

AI Technical Summary

Problems solved by technology

However, in the heat treatment performed after the capacitor element is formed, treatment conditions higher than the film formation temperature of the capacitor film are sometimes used, and the recrystallization of the tungsten silicide film is caused by such heat treatment.

As a result, the contact state between the capacitive film and the tungsten silicide film becomes uneven, resulting in a decrease in the withstand voltage of the capacitive film.

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