Strain-induced recrystallization behavior in single-crystal copper processing wires: The role of trace Y on mechanical property evolution at room temperature

Single-crystal copper processing wire as a critical conductive material for transmission wires in integrated circuits, plays an essential role in ultra-fine processing due to its superior plastic deformation capability. This study investigates the evolution of plastic deformation and microstructural changes in single-crystal copper processing wire under high strain conditions with the addition of the rare earth element Y. Furthermore, the influence of the rare earth element Y on the mechanical properties, microstructure development, and texture composition of single-crystal copper processing wire is systematically examined. The study employed scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), three-dimensional atom probe tomography (3D-APT), and transmission electron microscopy (TEM) for material analysis and characterization. A Y-O atomic mutual attraction model was developed to analyze the nanoscale precipitated phases. The results indicate that a “Y-O″ phase forms at ε ≥ 3.68, accompanied by a “self-annealing” phenomenon. Specifically, during room temperature plastic deformation, the tensile strength of Cu-0.03Y processing wire (291.73 MPa) decreases by 35.4 %, while its elongation(5.75 %) increases by 751 % compared to that of single-crystal copper processing wire (0.675 %). The presence of multi-scale precipitates, including nanoscale Y₂O₃ and micron-scale Cu₅Y precipitates, in micro-alloyed single-crystal copper processing wires induces significant lattice distortion and enhances the cumulative dislocation density. The high dislocation density facilitates dislocation reorganization, subgrain rotation, and the transition from LAGBs to HAGBs, thereby increasing the volume fraction of <100> and <110> fiber textures and promoting recrystallization.