The increasing complexity and miniaturization of microelectronic devices require accurate and computationally efficient tools to predict thermomechanical residual stresses within interconnection stacks of integrated circuits. We introduce a computational strategy that couples domain decomposition (DD) techniques with a reduced-order modeling (ROM) framework tailored for complex 3D geometries. By partitioning the design layout into subdomains, this approach enables localized model order reduction, accelerating simulation runtime. Our method represents the detailed geometry of a layer of metal interconnects in a ceramic matrix and accounts for linear elastic deformations induced during fabrication process. For each subdomain, we construct reduced bases via proper orthogonal decomposition of high-fidelity finite element method (FEM) solutions, called snapshots, computed under physically motivated boundary conditions. In the initial phase, we focus on purely mechanical effects, applying the approach to a representative subdomain with over one million degrees of freedom. Assuming small perturbations, the primary quantity of interest is the displacement field. The dimensionality is reduced from over one million degrees of freedom to approximately 30–50 modes per subdomain. The ROM demonstrates excellent agreement with the FEM solution of the concerned subdomain, achieving a global relative error below 0.6%. Highest local relative errors per node and degree of freedom remain under 3%. In terms of performance, the ROM provides more than a tenfold acceleration in computational time compared to the FEM model. These results confirm the method’s reliability for industrial-scale applications. This DD-based ROM framework enables efficient estimation of residual stresses in complex 3D microelectronic structures and aims to support early-stage design optimization of integrated circuits. Further results, including the integration of coupled thermo-mechanical effects under homogeneous temperature field and the reconstruction of full-domain solutions through DD, will be presented.