Method for wafer-level semiconductor die attachment 

A wafer-level semiconductor die attachment method includes placing a semiconductor die of a plurality of semiconductor dies at an initial placement position to overlap a sub-mount pad on a sub-mount of a pre-singulated wafer. A die pad of the semiconductor die comes in contact with a solder layer deposited over the sub-mount pad. The semiconductor die and the sub-mount include a plurality of die and sub-mount mating features, respectively. The solder layer is heated locally to temporarily hold the semiconductor die at the initial placement position. The pre-singulated wafer is reflowed, when each semiconductor die is temporarily held at the corresponding initial placement position. During reflow, each semiconductor die slides from the initial placement position and a contact is established between the corresponding plurality of die and sub-mount mating features. Thereby, each semiconductor die is permanently attached to the corresponding sub-mount.