pRSM: models for model-based litho-hotspot repairs

Abstract

Computing repair hints for litho hotspots is made more effective with a model of how Process Window contour bands changes as a function of design layout changes. We have developed a modeling methodology called pRSM (Partition Response Surface Model). In our approach, we create a family of models along with error bound estimate models. We first classify design layout configurations into a small number of partition categories and then build a RSM model and error bound model for each partition category. In this paper we describe our pRSM methodology and present results illustrating the advantages of our methodology over that of traditional RSM approaches.

Model-based hints for litho-hotspots repair

“…Our model takes an input the drawn layout geometries and produces an estimate of the contour locations relative to the design edges. The process of generating pRSM models is covered in a companion paper [1] . Then, for each litho-hotspot, a collection of candidate repair hints are evaluated to generate hints that may be taken by physical implementation tools, based on the pRSM models.…”

“…The principle of this selection process are better described in a companion paper [1] , the details will be discussed later in this paper.…”

“…In order to predict the impact of a candidate repair on the printed contour without going through expensive lithosimulation, we adopt the pRSM methodology, which is described in detail in a companion paper [1] . To utilize the pRSM methodology, the partition which the layout around litho-hotspots belongs to needs to be identified first, so that a feature model may be picked.…”

“…A companion paper [1] presents a methodology which allows fairly accurate estimates how design layout changes will impact the printed contours based on Partition Response Surface Methodology (pRSM). The term partition arises since our pRSM methodology can be thought of as a collection of RSM models which are valid only within its layout partition category.…”

Model based hint for litho hotspot fixing beyond 20nm node

“…Modifying the layout edges in order to fix the hotspot is complicated, as the mapping from a design layout to a printed contours involves a sequence of complex non-linear steps such as RET step which alters the original layout shapes and optical effects which takes into account the effect of the layout features context [3].…”