Steps in Physical Design: From Netlist Generation to Layout Post Processing

Abstract

Due to its complexity, the physical design process is divided into several primary steps. Having introduced in Chap. 4 the flow, constraints and methodologies of today’s physical design process, we now investigate the various steps required to generate its output: a layout. These steps, which transform a netlist into optimized mask data, are dealt with one by one in this chapter. A layout is generated from a netlist. We first describe how a netlist is created, that is, either by using hardware description languages (HDLs) in digital design (Sect. 5.1), or by deriving it from a schematic, as is common in analog design (Sect. 5.2). Then the physical design steps, comprising partitioning, floorplanning, placement, and routing, are presented in detail (Sect. 5.3). All of these steps are supported by highly sophisticated EDA tools in the case of digital designs, which is our focus here. We also discuss in this section the key aspects of symbolic compaction, standard-cell design and PCB design. When the physical design phase is completed, the resulting layout must be verified. This verification step confirms both functional correctness and design manufacturability. Methodologies and tools for comprehensive design verification, with a focus on physical verification, are covered in Sect. 5.4. Finally, we briefly touch on layout post-processing methodologies, such as resolution enhancement techniques (RET), that might impact physical design (Sect. 5.5).