Fin-type field effect transistor and manufacturing method thereof

A method of manufacturing a fin-type field effect transistor, comprising:

• sequentially forming a first mask and a second mask on a semiconductor substrate;
• patterning the second mask;
• forming a third mask on the second mask, and patterning the third mask in accordance with a fin pattern of the fin-type field effect transistor;
• etching the semiconductor substrate, the first mask, and the second mask through the third mask, wherein a first trench is formed in the semiconductor substrate;
• removing the third mask;
• etching the first mask through the second mask, and subsequently removing the second mask;
• etching the semiconductor substrate through the first mask to form a plurality of fins and a second trench disposed between adjacent fins, wherein the etching of the semiconductor substrate further deepens the first trench such that a depth of the first trench is greater than a depth of the second trench;
• and
• forming the fin-type field effect transistor on the semiconductor substrate, wherein a dielectric material is disposed in the first trench and the second trench.