Filling of Sub-μm Through-holes by Self-sputter Deposition

Filling of sub-µ m holes with a high aspect ratio by self-sputter deposition of copper is investigated. Good bottom coverages of 100% by means of thinner thin-film deposition and 50% by thicker thin-film deposition are attained. It is found that the bottom coverage decreases sharply when the ratio of the distance between the target and the substrate, D st, to the diameter of the erosion center ring is less than 1, and although the bottom coverage by the self-sputter deposition at lower pressures saturates at longer D st, that by the conventional sputter deposition at higher pressures decreases with D st. The bottom coverage also decreases with increases of the pressure, the thin film thickness deposited, and the radial distance of the substrate position from the target center toward the erosion center.