Multi-strand substrate for ball-grid array assemblies and method
AssigneeFreescale Semiconductor, Inc.
InventorNorman Lee Owen
Life of this patent
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Abstract
A multi-strand printed circuit board substrate for ball-grid array (BGA) assemblies includes a printed wiring board (11) having a plurality of BGA substrates (12) arranged in N rows (14) and M columns (16) to form an N by M array. N and M are greater than or equal to 2 and the size of the N by M array is selected such that each of the plurality of BGA substrates (12) maintains a planarity variation less than approximately 0.15 mm (approximately 6 mils). The printed wiring board (11) has a thickness (26) sufficient to minimize planarity variation and to allow a manufacturer to use automated assembly equipment without having to use support pallets or trays.
Claims22
A method for assembling ball-grid array (BGA) packages, comprising the steps of:
- providing a plurality of BGA substrates arranged in an N by M array within a printed circuit board having a thickness, wherein N and M are greater than or equal to 2, each BGA substrate having a plurality of bond posts and a plurality of contact pads;
- attaching a semiconductor die to each of the plurality of BGA substrates, wherein each BGA substrate corresponds to an attached semiconductor die, each semiconductor die having a plurality of bond pads;
- encapsulating the semiconductor die with an encapsulant;
- curing the encapsulant;
- and
- dividing the N by M array into separate BGA packages, wherein the size of the N by M array and the thickness of the printed circuit board are such that each of the plurality of BGA substrates maintains a planarity variation less than approximately 0.15 mm after assembly.
Dependencies are inferred from the claim text.