A Novel Structure with Modified Surface Characteristic for an AIN Substrate

摘要

A pseudoternary system 20 wt.% AIN - 75 wt.% Al_2O_3 - Y_2O_3 was used as raw powders. In order to decrease the dielectric constant and weight, 0, 5, 10, and 15 wt.% microspheres were respectively added into the system as sacrificial hollows. The mixture has been horizontal ball milled and employed to tape casting. Considering the would-be dramatic decrease in thermal conductivity and mechanical strength due to the introduction of porosity, the idea of novel sandwich structure was put forward, which was to apply 0 wt.%-microsphere-added tape (denoted as solid tape) as the surface and bottom layers and in between employed the 5,10, and 15 wt.% microsphere added tapes respectively. As comparison, non-sandwich structure was stacked. After sintering the debonded tapes in nitrogen at 1680℃ for 12 hours, a significant percentage of AIN was achieved. Relative density and dielectric constant were measured, indicating that with the increasing addition of the microspheres, both properties decreased. CTE was measured showing that the porosity has no influence on the value.