Method for providing whisker-free aluminum metal lines or aluminum alloy lines in integrated circuits
View Patent ↗A method for providing whisker-free aluminum metal lines or aluminum alloy lines in integrated circuits includes the following steps: providing a substrate; providing a whisker-containing layer made of aluminum metal or an aluminum alloy on the substrate; back-etching and/or resputtering the whisker-containing layer such that the whiskers are essentially removed; and structuring the whisker-free layer into the lines.
1. A method for providing whisker-free aluminum metal lines or aluminum alloy lines in integrated circuits, which comprises:
providing a substrate;
forming a whisker-containing layer of aluminum metal or an aluminum alloy on the substrate;
substantially removing the whiskers by etching back the whisker-containing layer to form a substantially whisker-free layer; and
structuring the whisker-free layer to form the lines.
2. The method according to claim 1 , which comprises etching back in a DSP (Dilute Sulphuric acid hydrogen Peroxide) step using H202 and H 2 SO 4 as primary etchants.
3. The method according to claim 1 , which comprises, prior to the removing step, forming a liner layer on the whisker-containing layer and, following the removing step, performing an oxidation step for oxidizing an exposed part of the whisker-free layer.
4. The method according to claim 3 , wherein the oxidation step is an O 3 plasma step.
5. The method according to claim 1 , wherein the step of forming the whisker-containing layer of aluminum metal or aluminum alloy is a sputtering step, and the removing step is performed in situ with the sputtering step.
6. The method according to claim 1 , wherein the whisker-containing layer is formed of AlCu.
7. The method according to claim 3 , wherein the liner layer is a layer formed of at least one material selected from the group consisting of Ti and TiN.