Semiconductor device and manufacturing method thereof

A method comprising:

• receiving a gate structure comprising:
• a high-k dielectric layer;
• one or more work function metal layers;
• a silicon cap (scap) layer comprising a silicon oxide material;
• and
• a glue layer comprising titanium nitride (TiN);
• pretreating a top surface of the gate structure using oxygen (O2) gas;
• depositing fluorine free tungsten (FFW) material over the gate structure during first deposition operations, wherein a discontinuous W cap is formed over the gate structure;
• etching back the FFW material over the scap layer during first etching operations using an ozone solution (DIO3), wherein a top surface of the scap layer is exposed for further processing;
• etching the top surface of the scap layer during second etching operations using dilute hydrofluoric acid (dHF), wherein a recess is formed in the scap layer;
• depositing additional FFW material over the gate structure including the recess in the scap layer during second deposition operations, wherein a continuous FFW cap is formed;
• and
• containing lateral growth of the continuous FFW cap by removing unwanted FFW material from a surface of gate spacers using an ozone solution (DIO3) during third etching operations.

A method comprising:

• receiving a gate structure over a semiconductor substrate, the gate structure comprising:
• a high-k dielectric layer;
• one or more work function metal layers;
• a silicon cap (scap) layer comprising a silicon oxide material;
• and
• a glue layer;
• and
• forming a continuous tungsten (W) cap over the gate structure, the continuous W cap comprising:
• a first W material layer disposed over the high-k dielectric layer, the one or more work function metal layers, and the glue layer;
• and
• a second W material layer disposed over the first W material layer and a recess in a top surface of the scap layer that is not covered by W material from the first W material layer.