Method for forming metal line of image sensor
Disclosed is a method for forming a metal line. The method includes preparing a semiconductor substrate having a first metal line, performing an oxidation process with respect to the first metal line, performing an oxide removal process to remove an oxide generated in the oxidation process, forming an etch stop layer on the metal line, forming an interlayer dielectric layer on the first metal line, and forming a damascene pattern on the interlayer dielectric layer, and forming a second metal line, which is connected with the first metal line, in the damascene pattern. The oxidation process for the first metal line can include a hydrogen peroxide treatment process using a solution including oxygen. The oxide removal process can be performed by using an oxalic acid (HOOC—COOH) solution.
1. A method for forming a metal line, comprising:
preparing a semiconductor substrate having a first metal line;
performing an oxidation process with respect to the first metal line;
performing an oxide removal process to remove an oxide of the first metal line generated in the oxidation process;
forming an etch stop layer on the first metal line only on an area where the oxide of the first metal line has been removed;
forming an interlayer dielectric layer on the first metal line including the etch stop layer, and forming a damascene pattern on the interlayer dielectric layer; and
forming a second metal line, which is connected with the first metal line, in the damascene pattern.
2. The method of claim 1 , wherein performing the oxidation process with respect to the first metal line comprises using a solution including oxygen.
3. The method of claim 2 , wherein using the solution including oxygen comprises using a hydrogen peroxide (H 2 O 2 ) solution.
4. The method of claim 1 , wherein performing the oxide removal process comprises using a solution that forms a chelate complex with copper oxide.
5. The method of claim 4 , wherein the solution is an oxalic acid (HOOC—COOH) solution.