CMP slurry for forming aluminum film, CMP method using the slurry, and method for forming aluminum wiring using the CMP method

A method of forming an aluminum wiring, comprising:

• forming an inter metal dielectric (IMD) layer comprising silicon oxide over a semiconductor substrate;
• patterning the IMD layer to define an aluminum wiring region;
• forming a metal barrier layer on the patterned IMD layer to obtain a resultant structure;
• coating the resultant structure with an aluminum film;
• and
• forming aluminum wirings within the aluminum wiring region defined within the patterned IMD by performing a two-step chemical mechanical polishing (CMP) process,
• wherein the two-step CMP process comprises:
• performing a first CMP which removes a part of the aluminum film using a first slurry comprising a polishing agent, an oxidant, a pH control additive, and an oxide film removal retarder which reduces a removal rate of the silicon oxide film, wherein the first slurry is devoid of a defect prevention agent which inhibits at least one of scratch defects and corrosion defects at a surface of the aluminum film;
• stopping the first CMP when a predetermined thickness of the aluminum film remains on a top surface of the metal barrier layer;
• forming the aluminum wirings within the aluminum wiring region by performing a second CMP which removes another part of the aluminum film using a second slurry comprising a polishing agent, an oxidant, a pH control additive, an oxide film removal retarder which reduces a removal rate of the silicon oxide film, and a defect prevention agent which inhibits at least one of scratch defects and corrosion defects at a surface of the aluminum film.