Abstract: The present invention includes the steps of providing a substrate having a main surface; depositing a dual-metal layer such as Mo/AlNd, MoW/AlNd, MoW/Al onto the main surface of the substrate; defining gate and word line patter using a layer of photoresist; and using the photoresist as an etching mask, a first metal dry etching process is carried out to etch the dual-metal layer at an etching selectivity that is significantly higher than prior art. The first metal dry etching process uses oxygen/fluorine containing etching gas mixture and oxygen/chlorine containing etching gas mixture to form the dual-metal gate and word line pattern having slightly oblique sidewalls. End point detection mode detected at 704 nm is used in the first metal dry etching process.

Abstract: A method for cleaning a plasma chamber after metal etching. First, a substrate having a metal layer thereon is placed in a plasma chamber. Next, the metal layer is etched. Finally, the substrate is removed from the plasma chamber to perform a dry cleaning which includes the following steps. First, the inner wall of the plasma chamber is cleaned by plasma etching using oxygen as a process gas. Next, the top and bottom electrode plates in the plasma chamber are cleaned by plasma etching using chlorine and boron chloride as process gases. Next, the inner wall of the plasma chamber is cleaned again by plasma etching using sulfur hexafluoride and oxygen as process gases. Finally, oxygen and helium used as purging gases are injected into the plasma chamber and exhausted from therein.

Abstract: The present invention includes the steps of providing a substrate having a main surface; depositing a dual-metal layer such as Mo/AlNd, MoW/AlNd, MoW/Al onto the main surface of the substrate; defining gate and word line patter using a layer of photoresist; and using the photoresist as an etching mask, a first metal dry etching process is carried out to etch the dual-metal layer at an etching selectivity that is significantly higher than prior art. The first metal dry etching process uses oxygen/fluorine containing etching gas mixture and oxygen/chlorine containing etching gas mixture to form the dual-metal gate and word line pattern having slightly oblique sidewalls. End point detection mode detected at 704 nm is used in the first metal dry etching process.

Abstract: A method for cleaning a plasma chamber after metal etching. First, a substrate having a metal layer thereon is placed in a plasma chamber. Next, the metal layer is etched. Finally, the substrate is removed from the plasma chamber to perform a dry cleaning which includes the following steps. First, the inner wall of the plasma chamber is cleaned by plasma etching using oxygen as a process gas. Next, the top and bottom electrode plates in the plasma chamber are cleaned by plasma etching using chlorine and boron chloride as process gases. Next, the inner wall of the plasma chamber is cleaned again by plasma etching using sulfur hexafluoride and oxygen as process gases. Finally, oxygen and helium used as purging gases are injected into the plasma chamber and exhausted from therein.