| abstract |
The high density plasma metal etch rate of a conductive material within a dense array of conductive lines is increased to no less than the etch rate of the conductive material in a bordering open field by injecting a sufficient amount of nitrogen into the total gas flow of the plasma. The injection of nitrogen in amounts of about 15% and 50% by volume of the total gas flow effectively reduces the etch rate differential between the dense array and open field, thereby reducing overetching, resist loss, and oxide loss in the open field, and facilitating planarization. |