Routing of Monotonic Parallel and Orthogonal Netlists for Single-Layer Ball Grid Array Packages


IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E89-A   No.12   pp.3551-3559
Publication Date: 2006/12/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e89-a.12.3551
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Physical Design
ball grid array,  monotonic,  single-layer,  package,  routing,  

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Ball Grid Array packages in which I/O pins are arranged in a grid array pattern realize a number of connections between chips and PCB, but it takes much time in manual routing. So the demand for automation of package routing is increasing. In this paper, we give the necessary and sufficient condition that all nets can be connected by monotonic routes when a net consists of a finger and a ball and fingers are on the two parallel boundaries of the Ball Grid Array package, and propose a monotonic routing method based on this condition. Moreover, we give a necessary condition and a sufficient condition when fingers are on the two orthogonal boundaries, and propose a monotonic routing method based on the necessary condition.