Predictive formulae for OPC with applications to lithography-friendly routing

Abstract

Due to the sub-wavelength lithography, manufacturing sub-90 nm feature sizes require intensive use of resolution-enhancement techniques, among which optical proximity correction (OPC) is the most popular technique in industry. Considering the OPC effects during routing can significantly alleviate the cost of post-layout OPC operations. In this paper, we present an efficient, accurate, and economical analytical formula for intensity computation and develop the first modeling of post-layout OPC based on a quasiinverse lithography technique. Extensive simulations with SPLAT, the golden lithography simulator in academia and industry, show that our intensity formula has high fidelity. Incorporating the OPC costs computed by the quasi-inverse lithography technique for our post-layout OPC modeling into a router, the router can be guided to maximize the effects of the correction. Compared with a rulebased OPC method, the experimental results show that our approach can achieve 14% and 16% reductions in the maximum and average layout distortions, respectively.

EPIC: Efficient prediction of IC manufacturing hotspots with a unified meta-classification formulation

“…(4) and that outp approximates certain target yp. The models shown here are customized with single hidden layer of neurons, with transfer functions denoted as f hid .…”

“…Meanwhile in recent years, CAD methodologies have evolved to incorporate RET models into early design stages (e.g., detailed routing) to avoid lithography-unfriendly patterns in a correct-by-construction manner [2][3][4][5][6]. Consequently, fast and accurate lithography hotspot detection becomes a common and critical issue for a wide range of applications in both design and manufacturing.…”

Lithography friendly routing: From construct-by-correction to correct-by-construction

“…Then, the lithocost is evaluated from the table based on the interaction between the patterns within the lithography window. Chen et al [27] develop a predictive modeling based on an inverse-like lithographic technique to numerically quantify the OPC cost as a routing guidance. However, these metrics do not show correlation with the post-OPC silicon image fidelity.…”

“…Considering the already heavy burden of routing tools, the optimization strategy should be efficient and provide good trade-off between printability and other traditional objectives. In [27], litho-cost minimization for each net are performed individually without considering the balance between different nets, which may lead to local optimality. Huang at al.…”

“…However, one has to be very conscious about the runtime as the lithography simulators could take prohibitive CPU [4]. In terms of which routing stage to apply lithography correction, there are two main paradigms, i.e., construct-by-correction [4], [5], [25] and correct-by-construction [1], [3], [26], [27]. In the construct-by-correction paradigm, the design is first routed as usual, then the litho-hotspots are detected (e.g., by some rules of thumbs or lithography simulations/models) and fixed as a post-routing optimization.…”