Abstract: A heat spreader to be molded into an encapsulated IC package in contact with a die attach pad carrying an IC die is adapted to be placed in a substantially rectangular mold cavity and to retain its position in the cavity while encapsulation material is injected. The heat spreader has a body portion with appendages extending toward each of the four walls, and the ends of the appendages furthest from the body are formed downward such as by bending to provide a support for the spreader from the bottom surface of the mold cavity substantially at the lines where the sidewalls meet the bottom surface of the mold cavity. In a preferred embodiment there are two appendages toward each sidewall, and the heat spreader before and during the molding process is supported from the bottom surface of the mold cavity by dimples through the body, forming additional supports.

Abstract: A method for manufacturing a plastic encapsulated integrated circuit (IC) package has steps for placing a diamond substrate in a lower cavity of an encapsulation mold such that the diamond substrate in the finished package underlies the die attach pad and a portion of the leads in close proximity to each. Pins are provided in lower cavities of molds to support and/or position diamond substrates to lie close to both die attach pads and leads to facilitate efficient heat transfer from an operating IC, through the die attach pad, into and through the diamond substrate, and finally to the leads leading from the encapsulated package. Apparatus is disclosed for positioning and supporting diamond substrates, and combination heat slugs for the purpose are disclosed, having diamond substrates bonded to metal slugs.