FIGS. 2A-3G are the perspective views and cross-sectional views showing the FinFET at various stages of the manufacturing method for forming a FinFET according to some embodiments of the present disclosure.

FIGS. 4A-4E are cross-sectional views showing FinFETs fabricated with different etching processes according to some embodiments of the present disclosure.

The following disclosure provides many different embodiments or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.