The chip packaging structure is commonly considered to be composed of different material layers stacked together. Due to the inconsistent thermal expansion coefficients of materials, the structure is prone to thermal warping deformation when subjected to significant changes in ambient temperature. At present, thermal warping is a typical failure mode in the field of microelectronic packaging. With the development of ultra-thin packaging components, thermal warping will become more pronounced. However, excessive warping deformation can lead to problems such as chip cracking, interface delamination, and solder joint failure. First, this paper considers the actual size differences between bare chips and substrates, and establishes a heterogeneous stepped double-layer plate model. Second, a thermal warpage experiment platform was constructed using a VIC-3D non-contact full-field strain gauge based on 3D digital image correlation, an infrared thermal imager, and a high-temperature heating stage. Then, the thermal warping deformation of the double-layer plate structure was observed during the heating process, and an equivalent finite element model was established to verify the experimental results. Subsequently, the thermal warpage control of the stepped double-layer board was achieved by attaching a frame sub-structure to the edge of the bottom plate, with its effectiveness verified through both simulations and experiments. Finally, the effects of the geometric and material parameters of the frame sub-structure on the thermal warpage control of the stepped double-layer plate structure are also discussed in detail. It is found that the thermal warping deformation obtained through experimental methods is in good agreement with the simulation results. Moreover, the warping control method using the frame sub-structure can significantly reduce the thermal warping deformation of the heterogeneous stepped double-layer plate structure. The width of the frame structure is the primary factor, and increasing the width can reduce thermal warping deformation effectively. The coefficient of thermal expansion and thickness also have a significant impact on the thermal warping control. As the coefficient of thermal expansion and thickness increase, the thermal warping deformation decreases. The research findings of this paper can provide theoretical guidance for solving thermal warping issues in multi-material laminated structures in microelectronic packaging.