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Autorouting Module

Creating connections between components takes a large part of the layout implementation time for any integrated circuit. This is also becoming more important for PIC designs, as the number of components being deployed in PICs is increasing and both optical as well as electrical connections must be made. The routing rules for PICs are significantly different than in digital CMOS ICs. Photonic connections are made using waveguides that are curvilinear in nature to reduce light loss, reflections and dispersion. Waveguides are typically single-layer, but crossings with other waveguides are sometimes allowed (at a cost).

The OptoDesigner Autorouting module provides the capability to perform both optical and electrical multi-net autorouting on a chip. The Autorouting module is rules and cost-based, giving layout engineers the ability to adjust both rules and costs for different routing layers and types. As an example, you can combine 45-degree waveguide routing with two- or four-layer metal Manhattan-style routing in the same chip, each avoiding their own obstacles.

Benefits

Routing is error prone and time consuming. The Autorouting module removes the tedium of manual routing, freeing up the layout engineer to explore more options for creating optimal placement and circuit design. The autorouting module seamlessly integrates with validated building blocks of multiple PDKs, allowing engineers to simulate the impact of the routing with other simulation tools, such as OptSim Circuit.

Applications

The metal autorouting is mostly meant for DC and lower-speed RF routing. It can be applied to all technologies ranging from Silicon photonics through III-IVs to PLCs.

Waveguide autorouting is most suitable for silicon photonics or other technologies with small bending radii, since the routing grid needs to be finer than the radius used. For technologies with a higher refractive index contrast material system, we recommend our Advanced Connectors Module. This module does not use a grid, but creates optically correct freeform connections such as a sine bend between components in the PIC layout.

Features

Metal Routing

• Single-layer or multi-layer metal routing
• 90-degree or 45-degree routing
• Adjustable costs for VIAs

Optical Waveguide Routing

• Single-layer photonic routing
• 90-degree or 45-degree routing
• You can select PCells for bends, straights and crossings; each can be any (user or PDK-defined) PCell
• You or the PDK can specify relative costs for bends and crossings
• Iterative maze routing aims to minimize global cost
• Prevent routing from overlapping with specific mask layers