Semiconductor structure and forming method thereof

The invention provides a semiconductor structure, which comprises a plurality of magnetic tunnel junction (MTJ) elements. Seen from a top view, the MTJ elements are arranged in an array, at least one second contact structure is located in the array arranged by the MTJ elements, and at least one first mask layer covers a top surface and two sidewalls of each MTJ element, when seen from a cross-sectional view, a sidewall of the first mask layer is aligned with a sidewall of a second metal layer which is disposed below the second contact structure.