Method of fabricating semiconductor device with void-free conductive feature

A method of manufacturing a semiconductor device, comprising:

• forming a transistor in a substrate;
• depositing an insulative layer on the substrate;
• forming a first trench penetrating through the insulative layer to expose a portion of a first impurity region of the transistor;
• performing a first cyclic process comprising a first sequence of a first deposition step and a first removal step to deposit a conductive material in the first trench until a height of the conductive material in the first trench is greater than a predetermined height;
• filling the first trench with the conductive material after the first cyclic process to thus form a first conductive feature;
• forming a storage capacitor contacting the first conductive feature;
• depositing an isolation layer to cover the insulative layer and the storage capacitor;
• forming a second trench penetrating through the isolation layer and the insulative layer to expose a portion of a second impurity region of the transistor;
• performing a second cyclic process comprising a second sequence of a second deposition step and a second removal step to deposit the conductive material in the second trench until a number of times of the second deposition step has been performed is equal to a third preset number of times and a number of times of the second removal step has been performed is equal to a fourth preset number of times;
• filling the second trench with the conductive material after the second cyclic process to thus form a second conductive feature;
• and
• forming a bit line connected to the second conductive feature.