Method of profile control in metal etching

A method of profile control for etching a metal layer positioned on a dielectric layer, wherein the metal layer comprises at least:

• an aluminum-alloy layer on the dielectric layer;
• an anti-reflection layer on the aluminum-alloy layer, and wherein the method of profile control for etching a metal layer comprises the steps of:
• performing a breakthrough step of a first etch recipe to remove the anti-reflection layer and a certain thickness of the aluminum-alloy layer until a predetermined depth is reached, wherein the first etch recipe provides a first source power, a first bias power, and a nitrogen gas as a reactive gas, and wherein the ratio between the first source power and the first bias power is about 1/3;
• and
• performing a main etch step of a second etch recipe having a higher etch rate than the first etch recipe to remove the remaining residue of the aluminum-alloy layer, wherein the second etch recipe provides a second source power, a second bias power, and a nitrogen gas as a reactive gas, and wherein the ratio between the second source power and the second bias power is about 10/3, wherein the choices of the reactive gases for the first etch recipe further include chlorine gas and BCl3.

A method of profile control for etching a metal layer positioned on a dielectric layer, wherein the metal layer comprises at least:

• an aluminum-alloy layer on the dielectric;
• an anti-reflection layer on the aluminum-alloy layer;
• and wherein the method of profile control for etching a metal layer comprises the steps of:
• performing a breakthrough step of a first etch recipe to remove the anti-reflection layer and a certain thickness of the aluminum-alloy layer until a predetermined depth is reached;
• and
• performing a main etch step of second etch recipe having a higher etch rate that the first etch recipe to remove the remaining residue of the aluminum-alloy, wherein the choices of reactive gases for both the first etch recipe and the second etch recipe include nitrogen gas, chlorine gas, and BCl3 gas.