System in package manufacturing method using wafer-to-wafer bonding

Embodiments of the present disclosure are related to manufacturing system-in-packages at wafer-level. In particular, various embodiments are directed to adhering a first wafer to a second wafer and adhering solder balls to contact pads of the first wafer. In one embodiment, a first wafer having first and second surfaces is provided. The first wafer includes bond pads located on the first surface that are coupled to a respective semiconductor device located in the first wafer. A second wafer having an electrical component located therein is provided. A conductive adhesive is provided on at least one of the first wafer and the second wafer. Conductive balls are provided on the bond pads on the first surface of the first wafer. The conductive balls and the conductive adhesive are heated to cause the conductive balls to adhere to the bond pad and the conductive adhesive to adhere the first wafer to the second wafer.