A method for manufacturing a thin semiconductor package includes providing a lead frame with a removable substrate that has an attaching surface attached to a first surface of the lead frame. The lead frame is formed from an electrically conductive sheet and has leads that extend inwardly from a lead frame boundary towards a central region of the lead frame. A semiconductor die is mounted on the removable substrate at the central region. The semiconductor die has a connection pad surface with die pads on it, and the connection pad surface is attached to the attaching surface of the removable substrate. The lead frame and die are encapsulated with a first encapsulant so that the lead frame is sandwiched between the first encapsulant and the removable substrate. The removable substrate is removed from the lead frame to expose the first surface of the lead frame and then the die pads are electrically connected to respective ones of the leads. The die and lead frame then are encapsulated with a second encapsulant so that the lead frame and die are sandwiched between the first and second encapsulants. Part of the first encapsulant is then removed to reduce the thickness of the package and expose the leads.