In recent years, directed self-assembly (DSA) has demonstrated tremendous potential to reduce cost for multiple patterning with fewer masks, especially for via patterning. DSA is considered as one of the next generation lithography candidates or complementary lithography techniques to extend 193i lithography further for the sub- 7 nm nodes. In this work, we focus on the simultaneous DSA guiding template assignment and decomposition with DSA and double patterning (DSA-DP) hybrid lithography for 7nm technology node. We first analyze the placement error of DSA patterns with different shapes and sizes. We then propose a graph-based approach to reduce the problem size and solve the problem more efficiently without affecting the optimality of the results. The experimental results demonstrate that we can achieve a 50% reduction in both the number of variables and constraints compared to previous work, which leads to a 50X speed up in runtime.
Standard cell pin access has become one of the most challenging issues for the back-end physical design in sub-14nm technology nodes due to increased pin density, limited number of routing tracks, and complex DFM rules/constraints from multiple patterning lithography. The standard cell I/O pin access problem is very difficult also because the access points of each pin are limited and they interfere with each other. There have been several studies across various standard cell and physical design stages, including standard cell pin access optimization, placement mitigation and routing planning, to achieve overall pin access optimization. In this paper, we will introduce a holistic approach across different design stages to deal with the pin access issue while accommodating the complex DFM constraints in advanced lithography.
For robust standard cell design, designers need to improve the intercell compatibility for all combinations of cells and cell placements. Multiple patterning lithography colorability check breaks the locality of traditional rule check, and N-wise checks are strongly needed to verify the colorability for layout interactions across cell boundaries. A systematic framework is proposed to evaluate the library-level robustness over multiple patterning lithography from two perspectives, including complete checks on two-row combinations of cells and long-range interactions. With complete checks on two-row combinations of cells, the vertical and horizontal boundary checks are explored to predict illegal cell combinations. For long-range interactions, random benchmarks are generated by cell shifting and tested to evaluate the placement-level efforts needed to reduce the manufacturing complexity from quadruple patterning lithography to triple patterning lithography for the middle-of-line (MOL) layers. Our framework is tested on the MOL layers but can be easily adapted to other critical layers with multiple patterning lithography constraints.
Multiple patterning (triple and quadruple patterning) is being considered for use on the Middle-Of-Line (MOL) layers at the 10<i>nm</i> technology node and beyond.<sup>1</sup> For robust standard cell design, designers need to improve the inter-cell compatibility for all combinations of cells and cell placements. Multiple patterning colorability checks break the locality of traditional rule checking and N-wise checks are strongly needed to verify the multiple patterning colorability for layout interaction across cell boundaries. In this work, a systematic framework is proposed to evaluate the library-level robustness over multiple patterning from two perpectives, including illegal cell combinations and full chip interactions. With efficient N-wise checks, the vertical and horizontal boundary checks are explored to predict illegal cell combinations. For full chip interactions, random benchmarks are generated by cell shifting and tested to evaluate the placement-level efforts needed to reduce the quadruple patterning to triple patterning for the MOL layer.
This paper reviews the escalation in design constraints imposed on 2<sup>nd</sup> level wiring by multiple patterning exposure techniques in the 10NM technology node (i.e. ~45nm wiring pitch) relative to the 14NM technology node (i.e. 64nm wiring pitch). Specifically, new challenges facing place-and-route tooling are outlined, solutions to overcome these challenges are reviewed, and a manufacturing ready implementation is demonstrated.