Patent References 3562058 Method for densifying leadframe conductor spacing Method of assembling tab bonded semiconductor chip package Lead frame for integrated circuits or the like and method of manufacture Patent #: 5176255 InventorAssigneeApplicationNo. 977523 filed on 11/17/1992US Classes:53/432, Vacuum or gas treating29/827, Beam lead frame or beam lead device53/471, With separate closure attaching (e.g., cap or plug)53/477, By heat sealing257/E21.499, Assembling semiconductor devices, e.g., packaging , including mounting, encapsulating, or treatment of packaged semiconductor (EPO)257/E23.128Encapsulation having cavity (EPO)ExaminersPrimary: Coan, James F.Attorney, Agent or FirmInternational ClassesB65B 031/00H01L 021/88 AbstractA semiconductor package includes a lead frame with a die or chip mounted on a die pad, a base made of a thermoplastic material and having a cavity, and a lid made of thermoplastic material ultrasonically welded to the base to cover the cavity and protect the electronic device in the package. The package may include a substrate with conductive traces.A method of attaching a lid to a semiconductor package base includes the steps of providing a semiconductor package base having an open cavity, providing a thermoplastic lid that covers the open cavity, placing the lid on the semiconductor package base so that the lid covers the open cavity, applying pressure to hold the lid and body together, and attaching the lid to the base by ultrasonically welding them together. | |