Both cost considerations and environmental concerns have prompted the search for alternative methods to electroless copper deposition on the walls of vias (holes used for interconnecting different levels of circuitry in printed wiring boards). One attractive possibility is sputter deposition (a dry metallization process) of copper onto hole walls. This requires a knowledge of deposit thickness as a function of depth into the hole. Experimental results are presented for the variation with depth in the thickness of copper deposited onto the walls of circular holes by sputtering. For large distances into holes oriented perpendicularly to the sputter source, the thickness of the deposit decreases with depth as (D/L)3, where D is the hole diameter, L is the distance into the hole, and L/D>2. The experimental results agree with the calculated values obtained by using Lambert’s law, where the emitted flux is integrated over the magnetron area from which the sputtered copper can travel to a particular region on the hole wall. The data are used to predict the deposit thickness as a function of depth into through holes which have been subjected to sputtered copper from both sides. For a deposit thickness on the outer planar surface of 25 000 Å, and holes with aspect ratios A of 1, 2, 3, 5, and 10, the predicted deposit thickness on the hole walls at the midplane are 13 600, 8400, 4400, 1200, and 160 Å, respectively.