A semiconductor structure includes providing a substrate including a first surface and a second surface opposite to the first surface. The first surface is a functional surface. The method also includes forming a plastic seal layer on the first surface of the substrate, and performing a thinning-down process on the second surface of the substrate after forming the plastic seal layer. The plastic seal layer provides support for the substrate during the thinning-down process, and thus warping or cracking of the plastic seal layer 240 may be avoided. In addition, the plastic seal layer can also be used as a material for packaging the substrate. Therefore, after the thinning-down process, the plastic seal layer does not need to be removed. As such, the fabrication process is simplified, and the production cost is reduced.