The present invention provides an alignment mark, the alignment mark includes at least one dummy mark pattern in a first layer comprises a plurality of dummy mark units arranged along a first direction, and at least one first mark pattern located in a second layer disposed above the first layer, the first mark pattern comprises a plurality of first mark units, each of the first mark units being arranged in a first direction. When viewed in a top view, the first mark pattern completely covers the dummy mark pattern, and the size of each dummy mark unit is smaller than each first mark unit. In addition, each dummy mark unit of the dummy mark pattern has a first width, each first mark unit of the first mark pattern has a second width, and the first width is smaller than half of the second width.