Methods and apparatus for filling features on a substrate are provided herein. In some embodiments, a method of filling features on a substrate includes: depositing a first metallic material on the substrate and within a feature disposed in the substrate in a first process chamber via a chemical vapor deposition (CVD) process at a first temperature; depositing a second metallic material on the first metallic material in a second process chamber at a second temperature and at a first bias power to form a seed layer of the second metallic material; etching the seed layer in the second process chamber at a second bias power greater than the first bias power to form an intermix layer within the feature comprising the first metallic material and the second metallic material; and heating the substrate to a third temperature greater than the second temperature, causing a reflow of the second metallic material.