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ABSTRACT

The International Technology Roadmap for Semiconductors' history details the growing complexity of device design and the latest device-manufacturer's techniques for tuning their process for each new design generation. In spite of the current desire to incorporate techniques termed 'Design for Manufacture' (DFM) into manufacturing, simulations and the design cycle, they do little more than optimize feature quality for ideal exposure conditions while testing for shorts, opens and overlay problems over process variations.
 The manufacturing linkage method in DFM simulation is performed by the adaptation of a technique unchanged in the last 30 years - 'process window analysis'. With this methodology, recent successes seen in chip-design have not taken their share of the burden of technology advancement. The lack of adequate manufacturing awareness in designs, coupled with materials design problems for extreme ultraviolet (EUV) lithography technology, recently redirected industry's path into critical layer splitting, a technique termed 'double patterning'.
Design Optimization by simulation focuses on feature layout optimization for resolution. Design solutions that take advantage of the full potential spectrum of mask-feature alternatives to increase the functional process space and to simplify setup in manufacturing do not exist since there is no method of feedback. A mechanism is needed that can quantify design performance robustness, with mask-contributions, to variations in the user's specific manufacturing process.
 In this study, a Process Behaviour Model methodology is presented for the analysis of feature profiles and films to derive the relative robustness of response to process variations for alternative optical proximity correction (OPC) designs. Analysis is performed without regard to the specific mechanics of the design itself. The design alternatives of each OPC feature are shown to be strong contributors not only to resolution and depth-of-focus but also to the stability of final image response; that is, the ability of the feature profile to remain at optimum under varying conditions of process exposure excursion.
A method of extracting the systematic component of each feature's design-iteration is derived, providing the ability to quantify the specific OPC response sensitivity to changes in the exposure and process films as well as drift intoduced by the tools of the exposure set.