A semiconductor package is provided. The semiconductor package includes an organic substrate, a stiffness layer, and a chip subassembly. The stiffness layer is formed on the organic substrate. The chip subassembly is disposed on the stiffness layer. The chip subassembly includes at least a first chip, a second chip, and a third chip. The second chip is disposed between the first chip and the third chip in a stacked orientation. The first chip, the second chip, and the third chip have the function of proximity communication.