DEEP TRENCH CAPACITOR AND MEHTOD OF REACTIVE ION ETCHING

摘要

PURPOSE: A method of forming trench capacitor in a DRAM is provided to increase the capacitance of DRAM cell. CONSTITUTION: In the method of forming trench capacitor, reactive ion etching is executed with the process gas one of which provide reactive ion suitable for etching and the other of which improve the state of deposition on the trench wall. In the process of etching the condition varies and the width or diameter of trench also varies. The change of condition is made by the change of temperature of wafer, gas composition ratio used in the etching process, gas pressure of process chamber, the temperature can be controlled by the stream of cooling water. The trench has one or more waist by the change of process condition.