Effect of Non-Uniform Temperature Field on Sintering Performance of Conductive Silver Paste in Laser Sintering.

Abstract

The non-uniform temperature field in laser sintering critically affects conductive silver paste performance, yet its quantitative relationship with sintering mechanisms remains unclear. This study addresses this issue by proposing effective sintering temperature (T_a) and effective sintering time (S_a) as metrics to link laser parameters and sintering temperature field with sintering performance. Through full-factorial experiments, finite element simulation, and in situ thermal monitoring, it was revealed that (1) Increasing laser power and reducing laser scanning speed effectively reduce resistivity. For example, at 10 W and 0.1 mm/s, the resistivity reached 6.81 μΩ·cm, which was 88.9% lower than the value of 61.11 μΩ·cm at 2 W and 0.5 mm/s. (2) The resistivity exhibits a threshold effect in its reduction across low-power (<3 W), medium-power (3~4 W), and high-power (>5 W) ranges. (3) The action of laser sintering parameters on sintering performance through T_a and S_a. The resistivity decreases are correlated with T_a, exceeding the exothermic peaks (T₁ = 196 °C and T₂ = 232 °C). Unlike prior qualitative analyses, this work quantifies how non-uniform temperature fields govern sintering through T_a and S_a, offering a quantitative method to analyze the temperature field's effect on sintering performance.