Computer system to control multiple step ionized metal plasma deposition process for conformal step coverage

摘要

A multiple step process sputter deposits material of uniform thickness on stepped surfaces of an integrated circuit substrate such as the surfaces of a high aspect ratio via or a narrow trench. Material is first sputter deposited at the bottom of the opening at high pressure using a high power RF source connected to a coil in the deposition chamber to couple energy into the plasma. A high power RF bias is applied to the substrate, and a low power DC bias is applied to the sputtering target. The same parameters are repeated in a second step except that the high power RF bias on the substrate support is either reduced to a low power level or reduced to zero (by the end of the second step) to deposit on the lowest quarter of the sidewall of the opening. In a third step, no RF bias is applied to the pedestal remains and the pressure is reduced to a medium pressure state, resulting in a deposition on the second quarter of the sidewall of the opening. In a fourth step, the RF power coupled to the plasma is reduced to a low level, resulting in deposition on the third quarter of sidewall of the opening. Finally, the last quarter of the sidewall of the opening is deposited upon by lowering the pressure further to a low pressure state and applying a high power DC bias to the target.