Al2O3-improved CaZr4(PO4)6 composite ceramics for matched to the thermal expansion of silicon wafers

During silicon wafer testing, a mismatch between the thermal expansion characteristics of the wafer probe card and the silicon wafer is likely to result in the probe not being able to maintain precise alignment with the various contact points on the wafer. To address this challenge, CaZr₄(PO₄)₆ + x wt% Al₂O₃ composite ceramics (CZPA, x = 0–25) are prepared by the solid-phase reaction method. when x = 5, the bulk density achieves the maximum value (3.17 g/cm³). Young's modulus reaches a maximum (58 GPa) at x = 5. The x- and y-axis shrinkages are in the range of 5.67%–8.67% and the z-axis shrinkage is in the range of 7.11%–9.91%. The coefficients of thermal expansion (CTE) gradually increase with the increase of Al₂O₃ doping and achieve a near-Si thermal expansion coefficient at x = 15, which means that it matches the thermal expansion of silicon wafers. This ceramic developed in this work is expected to be applied to multilayer-matched substrates matched to silicon.