Semiconductor structure and manufacturing method thereof

A method for forming a semiconductor structure, at least comprising the following steps:

• providing a substrate, having a dielectric layer disposed thereon, a first device region and a second device region defined thereon;
• forming at least one first trench in the dielectric layer within the first device region, at least one second trench and at least one third trench in the substrate within the second device region;
• forming a first work function layer in the first trench, the second trench and the third trench;
• forming a plurality of first material layers in the first trench, the second trench and the third trench, wherein the first material layer covers parts of the first work function layer disposed in the first trench and disposed on the sidewall of the second trench, and entirely covers the first work function layer disposed on the sidewall of the third trench;
• forming a second material layer to fill the first trench and the second trench after the first material layer is formed;
• removing the first material layer and the second material layer in the first trench;
• removing the second material layer in the second trench;
• and
• removing the first work function layer in the first trench entirely, and removing a partial first work function layer disposed in the second trench.