METHOD FOR ETCHING OXIDE LAYER IN DUAL DAMASCENE PROCESS

摘要

PURPOSE: A method for etching an oxide layer in a dual damascene process is provided to eliminate striation by eliminating a standing wave formed on the inner sidewall of photoresist in a dual damascene process and by performing an oxide layer etch process after polymer is deposited on the inner sidewall of the photoresist. CONSTITUTION: A copper layer(10), a silicon nitride layer(12) and an oxide layer(14) are sequentially stacked. The first photoresist is formed on the oxide layer except a via hole region . The standing wave on the inner sidewall of the first photoresist is eliminated and polymer is deposited on the inner sidewall of the first photoresist. A dry etch process is performed to eliminate the oxide layer except the first photoresist region by a predetermined depth. The first photoresist is eliminated. The second photoresist(18) is formed on the oxide layer except a trench region. A dry etch process is performed to eliminate the oxide layer in the trench region by a predetermined depth and remove the oxide layer in the via hole region and the silicon nitride layer.