Minimum separation for single-layer channel routing

Computers & Mathematics with Applications

Shih

1996

This paper considers the optimal offset, feasible offset, and optimal placement problems for a more general form of single-layer VLSI channel routing than has usually been considered in the past. Most prior works require that every net has exactly one terminal on each side of the channel. As long as only one side of the channel contains multiple terminals of the same net, we provide linear-time solutions to all three problems. Such results are implausible if the placement of terminals is entirely unrestricted; in fact, the size of the output for the feasible offset problem may be Ω(n 2). The linear-time results also hold with a ragged boundary on the side of the channel with multiple connections to the same net.

Section: Introductionmentioning

confidence: 99%

Single-layer channel routing and placement with single-sided nets

Computers & Mathematics with Applications

Shih

1996

“…Multiterminal nets can be handled by a transformation described in [7] (and known previously). Then a single-sided net has its two terminals on the same side of the channel, whereas a two-sided net is the type of net allowed in river routing.…”

Section: Introductionmentioning

confidence: 99%

Parallel algorithms for single-layer channel routing

Algorithms and Computation

Hung

Shih

1993

Self Cite

We provide efficient parallel algorithms for the minimum separation, offset range, and optimal offset problems for single-layer channel routing. We consider all the variations of these problems that are known to have lineartime sequential solutions rather than limiting attention to the "river-routing" context, where single-sided connections are disallowed. N ) 2 ) on the CRCW PRAM in the river routing context. In addition, wherever our results allow a channel boundary to contain single-sided nets, the results also apply when that boundary is ragged and N incorporates the number of bendpoints.

“…As mentioned earlier, it is actually possible to determine minimum required channel width for a single-layer problem in a more efficient fashion than performing the complete routing. In fact, linear time suffices to determine minimum channel width [12,11]. Thus, it becomes feasible to determine the true minimum width of B layers each time that a net assignment is considered, instead of relying on the density estimate until the end of net assignment.…”

Section: Resultsmentioning

confidence: 99%

MulCh: a multi-layer channel router using one, two, and three layer partitions

[1988] IEEE International Conference on Computer-Aided Design (ICCAD-89) Digest of Technical Papers

Ishii

Sangiovanni‐Vincentelli

Multilayer routing is an important problem in the physical design of integrated circuits as technology evolves towards several layers of metallization. MulCh is a channel router accepting specification of an arbitrary number of routing layers. Though several other channel routers for three layers of interconnect have been proposed, the only previously reported practical implementation for an arbitrary number of layers was that of Chameleon [4]. Chameleon is based on a strategy of decomposing the multilayer problem into two and three layer problems in which one of the layers is reserved primarily for vertical wire runs and the other layer(s) for horizontal runs. In some situations, however, it is advantageous to consider also layers that allow the routing of entire nets, using both horizontal and vertical wires. Hence, MulCh incorporates layers permitting this more general type of wiring. MulCh can route channels with any number of layers and automatically chooses a good assignment of wiring strategies to the different layers. The algorithms have been devised so that MulCh is expected to always perform at least as well as Chameleon in terms of area occupied by the routing. In test cases, MulCh shows significant improvement over Chameleon in terms of channel width, net length, and number of vias.