Abstract: Mold pieces (105 and 110) for molding a layer of mold compound on the interconnect side of a bumped semiconductor wafer (118) include a primary cavity (117) and secondary cavities (120) into which excess mold compound from the primary cavity (117) flows. The secondary cavities (120) include a plunger (130) that asserts a predetermined backpressure that is equal to a desired mold compound pressure on the mold compound during molding. As most of the excess mold compound in the primary cavity (117) is forced to flow into the secondary cavities (120), this advantageously leaves a relatively thin layer of mold compound on the semiconductor wafer (118), which can then be removed, for example by grinding, in a relatively short time. Mold piece (105) further comprises a movable cavity bar (115) that can be moved away from mold piece (105) after molding and be cooled to detach the molded substrate that adheres to the cavity bar.

Abstract: Mold pieces (105 and 110) for molding a layer of mold compound on the interconnect side of a bumped semiconductor wafer (118) include a primary cavity (117) and secondary cavities (120) into which excess mold compound from the primary cavity (117) flows. The secondary cavities (120) include a plunger (130) that asserts a predetermined backpressure that is equal to a desired mold compound pressure on the mold compound during molding. As most of the excess mold compound in the primary cavity (117) is forced to flow into the secondary cavities (120), this advantageously leaves a relatively thin layer of mold compound on the semiconductor wafer (118), which can then be removed, for example by grinding, in a relatively short time. Mold piece (105) further comprises a movable cavity bar (115) that can be moved away from mold piece (105) after molding and be cooled to detach the molded substrate that adheres to the cavity bar.