PCell Development and Validation & Automation of FQA LVS Test Suite Development Using SKILL Scripting

Abstract

Process Design Kit is that part of VLSI industry which deals with the process technology, i.e. masking procedures of different layers present or used particularly in that technology. Design kit means, an environment or a platform that is created for the users who uses these PDK’s for developing their own designs. So, these design kits do not have any particular functionality. Rather the users which are designers of various fields use these PDK to test their design’s functionality. Also this is important because this is the last step before the chip goes for manufacturing. Hence, it should be error free before it is being given for fabrication, else the chip will fail due to which the industries have to face huge loses. Hence PDK’s are extremely important for the industry point of view. Now, designing of these PDK’s are also done in frontend as well as in backend. In frontend the models are made and then these models are simulated using different simulators and finally they are cross checked and if discrepancies are found then they are fixed and again procedure repeats until all the discrepancies are resolved. Similarly, in backend, layouts are made for the various devices along with their test cases for the different DRC rules. These rules are validated and checked and if discrepancies are found then they are fixed and same procedure repeat itself. There are many other parameters which are to be taken care of like the LVS, DFM etc.A design kit is a unified set of data which provides, in a single environment, everything that is necessary to design and verify a cell/microcell/circuitry in a given CAD platform. PDKs are the logical equivalent of molecular DNA for the entire semiconductor industry: they are the basic building blocks underlying integrated circuit design. They necessarily include both physical and electrical parameters, constraints, rules, and models - things digested by design tools. PDKs fuel the engines that evaluate these parameters, rules, and models; they tend to be EDA vendor-specific. Because PDKs are integral to fabs, they tend to be foundry-specific as well. Hence, the PDK should be robust so that robust designs can be built on the platform. In a world of increasingly complex circuit designs and shorter time to market, first-pass silicon success is paramount to circuit designers. A well-made process design kit (PDK) can assist an integrated circuit (IC) designer to reach that goal by maximizing design productivity and providing a portal to the foundry where the IC will be fabricated. The EDA community develops PDKs that consist of multiple components including technology files, parameterized cells (PCells), and physical verification decks; the “process” in PDK refers to the specific semiconductor process technology for which the design kit has been built. The devices and parameters in a PDK are developed within foundry specifications to reduce human error and to enhance the likelihood that a design will function as intended. A simplified view of the IC design flow includes key PDK components, where different parts of the PDK are used for different activities within the design. Technology and display files are used throughout the design process-symbols and simulation components are used in schematic design, while layout design utilizes the layout view and physical verification decks.A technology file contains information, For the EDA tools such as layer definitions, layer colors, and GDSII stream translation rules for a given process technology. Depending on the particular EDA vendor tool, the technology file may also contain process rules and associated information, as well as symbolic devices.