Method of fabricating void-free conductive feature of semiconductor device

A method of fabricating a conductive feature, comprising:

• depositing an insulative layer on a substrate, wherein substrate has an impurity region;
• forming a trench in the insulative layer to expose the impurity region, wherein the trench has an upper corner defined at a top opening end of the trench;
• performing a cyclic process comprising a sequence of a deposition step and a removal step to deposit a conductive material in the trench to cover the impurity region until a number of times of the deposition step has been performed is equal to a first preset number of times and a number of times of the removal step has been performed is equal to a second preset number of times;
• and
• filling the trench with the conductive material after the cyclic process;
• wherein a first sequence of the deposition step of the cyclic process comprises:
• depositing the conductive material into the trench through the top opening thereof, wherein the conductive material is omni-directionally deposited on the insulative layer in direct contact with a top surface of the insulative layer, a sidewall of the trench, and the impurity region, wherein an excessive overhang of the conductive material is formed at the upper corner of the trench;
• and
• monitoring a thickness of the excessive overhang before the top opening of the trench is closed by the excessive overhang;
• wherein a first sequence of the removal step of the cyclic process comprises:
• trimming the excessive overhang to reduce the thickness thereof;
• and
• trimming a portion of the conductive material within the trench, such that the conductive material coated on the sidewall of the trench has a uniform thickness;
• wherein a second sequence of the deposition step of the cyclic process comprises:
• depositing the conductive material into the trench and on the conductive material deposited during the first sequence of the deposition step;
• and
• monitoring a thickness of the excessive overhang before the top opening of the trench is closed by the excessive overhang;
• wherein a second sequence of the removal step of the cyclic process comprises:
• trimming the excessive overhang to reduce the thickness thereof;
• and
• trimming a portion of the conductive material within the trench, such that the conductive material coated on the sidewall of the trench has a uniform thickness;
• wherein the uniform thickness of the conductive material after the first sequence of the removal step is equal to the uniform thickness of the conductive material after the second sequence of the removal step;
• wherein a first height of the conductive material within the trench after the first sequence of the deposition step is greater than a second height of the conductive material within the trench after the second sequence of the deposition step.