Material for metal line, metal line in semiconductor device and method for forming metal line in semiconductor device

A metal line in a semiconductor device, comprising:

• an oxide layer and a lower metal layer buried in the oxide layer;
• a barrier layer on a part of a surface of the oxide layer, which includes the lower metal layer;
• an alloy on the barrier layer;
• a reflectance reducing layer on the alloy;
• and
• a passivation layer surrounding the barrier layer, the alloy, and the reflectance reducing layer,
• wherein the alloy includes aluminum of 99% by weight to 99.8% by weight, copper of 0.1% by weight to 0.5% by weight, and scandium of 0.1% by weight to 0.5% by weight.

A method for forming a metal line in a semiconductor device, comprising:

• forming an oxide layer and a lower metal layer buried in the oxide layer on a semiconductor substrate;
• forming a barrier layer on an entire surface of the oxide layer, which includes the lower metal layer;
• forming an alloy on the barrier layer;
• forming a reflectance reducing layer on the alloy;
• patterning the alloy, along with the reflectance reducing layer, to form the metal line by performing a photo and etching process;
• passivating the metal line, the patterned reflectance reducing layer, and the barrier layer with an insulator;
• and
• performing a heat treatment,
• wherein the alloy includes aluminum of 99% by weight to 99.8% by weight, copper of 0.1% by weight to 0.5% by weight, and scandium of 0.1% by weight to 0.5% by weight.