Microwave Heating Sputtering Device for Copper Reflow

The patent replaces the thermal radiation heating system (heating lamp) with a microwave heating system. The microwave transmitter emits microwave energy that directly interacts with the wafer and deposited metal film, converting electromagnetic energy to thermal energy much more efficiently, thereby dramatically reducing the heating time and reflow process cycle time while achieving the required temperature for copper reflow.

The patent employs periodic cycling of the deposition and reflow processes multiple times. Each cycle consists of depositing a metal film followed by microwave-assisted reflow heating. Through repeated cycling, the deep trenches are progressively filled without forming hollow holes, ultimately achieving complete filling while maintaining controlled heating time in each cycle.

The patent performs preliminary deposition of a metal seed layer (such as copper, aluminum, or tungsten) on the deep trench structure before the main copper filling process. This preliminary layer serves as a foundation that modifies the subsequent deposition behavior, helping to control the growth rate and prevent excessive protrusion at the trench opening during later filling operations.

The patent utilizes microwave heating to change the thermal parameters of the deposited metal film during the reflow process. By controlling the temperature profile through microwave energy, the metal atoms gain enhanced surface mobility and can diffuse more uniformly into the deep trenches, transforming the deposition dynamics to achieve better filling uniformity and reduce protrusion formation.