METHOD FOR FORMING NARROW SHALLOW TRENCH ISOLATION BY DOUBLE NITRIDE ETCH PROCESS

摘要

PURPOSE: A method for forming a narrow shallow trench isolation(STI) by a double nitride etch process is provided to shrink a device by forming a narrow STI width generated as a design rule gradually decreases. CONSTITUTION: A thin initial oxide layer(20) and a nitride layer(30) are deposited on a silicon substrate(10). After a patterning process larger than a space as a target is performed, photoresist is stripped. A time etch process is performed to leave a predetermined thickness of the nitride layer. Another nitride layer(50) is deposited on the nitride layer. A double etch process using an etchback process is performed to form a trench(60). The space formed by a step of another nitride layer is a space of an ultimately desired target.