저널

In this work, handling of sapphire substrate for LED by using an electrostatic chuck was studied. The electrostatic chuck consisted of alumina dielectric, which was doped with 1.2 wt% $TiO_2$. As the volume resistivity of alumina dielectric was decreased, the electrostatic force was increased by Johnsen-Rahbek effect. The narrower width and gap size of electrode led to the stronger electrostatic force. When alumina dielectric with $3.20{ imes}10^{11}{Omega}{cdot}cm$ resistivity and 3 mm width/1.5 mm gap sized electrode was used, the strongest electrostatic force in this work was obtained, which value reached to ~14.46 gf/$cm^2$ at 2.5 kV for 4-inch sapphire substrate. This results show that alumina electrostatic chuck with low resistivity and fine electrode pattern is suitable for handling of sapphire substrate for LED.

Electrostatic chuck;Electrostatic force;Dielectric;Sapphire substrate;Volume resistivity;Electrode pattern;