Abstract: An atomic layer deposition apparatus includes a chamber, a vacuum pump to control a pressure in the chamber, a gas supply unit to supply a reaction gas into the chamber, a substrate holder disposed between the vacuum pump and the gas supply unit and having a heater, a mask assembly disposed between the substrate holder and the gas supply unit and having a cooling path to move coolant, and a coolant source to supply the coolant into the cooling path. The mask assembly is positioned a first distance from a substrate, and coolant is supplied into the cooling path of the mask assembly. The substrate is heated using the heater of the substrate holder, a pressure of the chamber is controlled using the vacuum pump, and reaction gasses are sequentially supplied through the gas supply unit.