Finfet stack gate memory and method of forming thereof

A method of forming a FinFET stack gate memory includes a nitride film forming step, a nitride film is formed on a memory cell area with a shallow trench isolation (STI) structure; a stripping step, a portion of the nitride film is stripped, the other portion of the nitride film is remained at the STI structure, and a STI oxide is disposed in the STI structure; a floating gate (FG) structure forming step, a tunnel oxide is disposed, and a first polysilicon is disposed to form a FG structure; an oxide-nitride-oxide (ONO) layer disposing step, a portion of the STI oxide is stripped, and an ONO layer is disposed; a removing step, a portion of the ONO layer is removed; a control gate (CG) structure forming step, a portion of the FG structure is removed, and a second polysilicon is disposed to form a CG structure.