A semiconductor structure includes a stacked structure. The stacked structure includes a first semiconductor die and a second semiconductor die. The first semiconductor die includes a first semiconductor substrate having a first active surface and a first back surface opposite to the first active surface. The second semiconductor die is over the first semiconductor die, and includes a second semiconductor substrate having a second active surface and a second back surface opposite to the second active surface. The second semiconductor die is bonded to the first semiconductor die through joining the second active surface to the first back surface at a first hybrid bonding interface along a vertical direction. Along a lateral direction, a first dimension of the first semiconductor die is greater than a second dimension of the second semiconductor die.