Equidistance routing in high-speed VLSI layout design

• Published in: Integration (Amsterdam) Vol. 38; no. 3; pp. 439 - 449
• Main Authors: Kubo, Yukiko, Miyashita, Hiroshi, Kajitani, Yoji, Tateishi, Kazuyuki
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2005; Elsevier Science
• Subjects: Applied sciences; Channel routing; Circuit properties; Design. Technologies. Operation analysis. Testing; Dynamic programming; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Equidistance routing; Exact sciences and technology; Integrated circuits; Minimization of total length; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Switch-box routing; Switching, multiplexing, switched capacity circuits; Symmetric-slant grid; Switch-box routing; Channel routing; Dynamic programming; Equidistance routing; Symmetric-slant grid; Minimization of total length; VLSI circuit; Circuit design; Integrated circuit design; Algorithm; Integrated circuit layout; Signal delay; Interconnection; Integrated circuit; Delay time; Selector switch
• DOI: 10.1016/j.vlsi.2004.07.008
• ISSN: 0167-9260

In VLSI layout design, certain nets in a given net set are required to propagate their signals within a tolerable skew of delays. Though the delay of the signal on a wire is determined by a complex environment, it is hard to satisfy this requirement unless all the concerned nets are routed within a certain skew of length. In this paper, we propose L-equidistance routing, which routes the concerned nets with a prescribed length L. After a basic technique of L-equidistance routing of a single 1-sink net, an algorithm is presented for the channel routing of plural multi-sink nets. The key idea is in the symmetric-slant grid interconnect scheme by which the problem is reduced to a grid routing problem. In L-equidistance routing of a channel, the total length of a n-sink net is not unique for n⩾3. An algorithm based on dynamic programming to solve this minimization problem is presented. Then, L-equidistance switch-box routing is discussed based on the L-equidistance channel routing. Algorithms are explained on the Euclidean space. But it is shown that a straightforward transformation of the routes to those on the Manhattan grid is possible keeping the property of equidistance. The proposing channel routing algorithm was implemented and applied to random data to demonstrate their ability.