Method of making thermally enhanced substrate-base package
An array-type package encasing one or more semiconductor devices. The package includes a dielectric substrate having opposing first and second sides with a plurality of electrically conductive vias and a centrally disposed aperture extending from the first side to the second side. A heat slug has a mid portion extending through the aperture, a first portion adjacent the first side of the substrate with a cross sectional area larger than the cross sectional area of the aperture and an opposing second portion adjacent the second side of the substrate. One or more semiconductor devices are bonded to the first portion of the heat slug and electrically interconnected to the electrically conductive vias. A heat spreader having a first side and an opposing second side is spaced from the semiconductor devices and generally parallel with the heat slug, whereby the semiconductor devices are disposed between the heat spreader and the heat slug. A molding resin encapsulates the semiconductor devices and at least the first side of the substrate, the first portion of the heat slug and the first side of the heat spreader.
1. A method for the manufacture of an array-type package for encasing one or more semiconductor devices comprising the steps of:
a) providing a heat slug array containing a dielectric substrate with a plurality of apertures and a plurality of interconnected heat slugs having opposing first and second portions separated by a mid-portion that extends through one of said plurality of apertures wherein said first portion has a perimeter larger than the perimeter of said one of said plurality of apertures, multiple tie bars projecting from said perimeter wherein a tie bar from one said heat slug intersects at least one other tie bar from an adjacent heat slug at an interconnection point;
b) bonding said one or more semiconductor devices to said first portion and electrically interconnecting said one or more semiconductor devices to electrically conductive vias on a first side of said dielectric substrate, said electrically conductive vias extending through said dielectric substrate to an opposing second side thereof;
c) providing an array of heat spreaders having multiple tie bars extending from a perimeter thereof wherein a tie bar from one said heat spreader intersects at least one other tie bar from an adjacent heat spreader at an interconnection point;
d) bonding tie bars of said heat slugs to tie bars of said heat spreader such that said one or more semiconductor devices are disposed between one of said heat slugs and one of said heat spreaders;
e) encapsulating said one or more semiconductor devices and at least a portion of said heat spreaders and heat slugs in a molding resin; and
singulating the array into individual components.
2. The method of claim 1 wherein said step of singulating is between the steps of (a) providing a heat slug array and (b) bonding said one or more semiconductor devices.
3. The method of claim 1 wherein said step of singulating is after the step of (e) encapsulating.
4. The method of claim 1 wherein said tie bars of said heat slugs and said tie bars of said heat spreaders are provided with features to facilitate alignment and bonding.
5. The method of claim 4 wherein one of said heat slugs and said heat spreaders is provided with projections and the other with mating apertures.
6. The method of claim 1 including the step of attaching solder balls to said electrically conductive vias on said second side.
7. The method of claim 6 wherein said solder balls are selected to have a diameter effective for a point on said solder balls opposite said second side to be coplanar with said second portion of said heat slug.
8. The method of claim 7 including the step of bonding both said solder balls and said second portion to an external circuit.