KEYWORDS: Directed self assembly, Connectors, Global Positioning System, Curium, Model-based design, Detection and tracking algorithms, Calibration, Monte Carlo methods, Data modeling, Failure analysis
Directed self-assembly (DSA) has emerged as one of the most compelling next-generation patterning techniques for sub 7 nm via or contact layers. A key issue in enabling DSA as a mainstream patterning technique is the generation of grapho-epitaxy-based guiding pattern (GP) shapes to assemble the contact patterns on target with high fidelity and resolution. Current GP generation is mostly empirical, and limited to a very small number of via configurations. We propose the first model-based GP synthesis algorithm and methodology for on-target and robust DSA, on general via pattern configurations. The final postoptical proximity correction-printed GPs derived from our original synthesized GPs are resilient to process variations and continue to maintain the same DSA fidelity in terms of placement error and target shape.
In this paper, we present a design technology co-optimization (DTCO) flow to pattern self-aligned via (SAV) using two
masks with grapho-epitaxy of lamella BCP and 193i for sub-7nm design. We show that it is necessary to consider both
metal and via layers at the same time in creating design rules with process variations. Due to lamella DSA’s own
characteristics, it can be easily applied in dense memory or SRAM applications for SAV patterning using traditional
single-material metal hard mask. However, to achieve two-mask SAV solution for logic applications, we need to apply
alternating hard mask in metal to cut lamella DSA patterns without compromising the technology scaling.
Directed Self Assembly (DSA) has emerged as one of the most compelling next generation patterning techniques for sub-7nm via or contact layers. A key issue in enabling DSA as a mainstream patterning technique is the generation of grapho-epitaxy based guiding pattern (GP) shapes to assemble the contact patterns on target with high fidelity and resolution. Current GP generation is mostly empirical, and limited to a very small number of via configurations. In this paper, we propose the first model-based GP synthesis algorithm and methodology for on-target and robust DSA, on general via pattern configurations. The final post-RET printed GPs derived from our original synthesized GPs are resilient to process variations and continue to maintain the same DSA fidelity in terms of placement error and target shape.
Directed Self Assembly (DSA) has emerged as one of the most compelling next generation patterning techniques for sub-7nm via or contact layers. A key issue in enabling DSA as a mainstream patterning technique is the generation of grapho-epitaxy based guiding pattern (GP) shapes to assemble the contact patterns on target with high fidelity and resolution. Current GP generation is mostly empirical, and limited to a very small number of via configurations. In this paper, we propose the first model-based GP synthesis algorithm and methodology for on-target and robust DSA, on general via pattern configurations. The final post-RET printed GPs derived from our original synthesized GPs are resilient to process variations and continue to maintain the same DSA fidelity in terms of placement error and target shape.
Directed Self-Assembly is the method by which a self-assembly polymer is forced to follow a desired geometry defined or influenced by a guiding pattern. Such guiding pattern uses surface potentials, confinement or both to achieve polymer configurations that result in circuit-relevant topologies, which can be patterned onto a substrate.
Chemo, and grapho epitaxy of lines and space structures are now routinely inspected at full wafer level to understand the defectivity limits of the materials and their maximum resolution. In the same manner, there is a deeper understanding about the formation of cylinders using grapho-epitaxy processes. Academia has also contributed by developing methods that help reduce the number of masks in advanced nodes by “combining” DSA-compatible groups, thus reducing the total cost of the process.
From the point of view of EDA, new tools are required when a technology is adopted, and most technologies are adopted when they show a clear cost-benefit over alternative techniques. In addition, years of EDA development have led to the creation of very flexible toolkits that permit rapid prototyping and evaluation of new process alternatives. With the development of high-chi materials, and by moving away of the well characterized PS-PMMA systems, as well as novel integrations in the substrates that work in tandem with diblock copolymer systems, it is necessary to assess any new requirements that may or may not need custom tools to support such processes.
Hybrid DSA processes (which contain both chemo and grapho elements), are currently being investigated as possible contenders for sub-5nm process techniques. Because such processes permit the re-distribution of discontinuities in the regular arrays between the substrate and a cut operation, they have the potential to extend the number of applications for DSA.
This paper illustrates the reason as to why some DSA processes can be supported by existing rules and technology, while other processes require the development of highly customized correction tools and models. It also illustrates how developing DSA cannot be done in isolation, and it requires the full collaboration of EDA, Material’s suppliers, Manufacturing equipment, Metrology, and electronic manufacturers.
We present a directed self-assembly (DSA) compliant flow for contact/via layers with immersion lithography assuming the graphoepitaxy process for the cylinders’ formation. We demonstrate that the DSA technology enablement needs co-optimization among material, design, and lithography. We show that the number of DSA grouping constructs is countable for the gridded-design architecture. We use template error enhancement factor to choose DSA material, determine grouping design rules, and select the optimum guiding patterns. Our post-pxOPC imaging data show that it is promising to achieve two-mask solution with DSA for the contact/via layer using 193i at 5 nm node.
In this paper, we present a DSA compliant flow for contact/via layers with immersion lithography assuming the grapho-epitaxy process for cylinders’ formation. We demonstrate that the DSA technology enablement needs co-optimization among material, design, and lithography. We show that the number of DSA grouping constructs is countable for the gridded-design architecture. We use Template Error Enhancement Factor (TEEF) to choose DSA material, determine grouping design rules, and select the optimum guiding patterns. Our post-pxOPC imaging data shows that it is promising to achieve 2-mask solution with DSA for the contact/via layer using 193i at 5nm node.
Multi-patterning (MP) is the process of record for many sub-10nm process technologies. The drive to higher densities has required the use of double and triple patterning for several layers; but this increases the cost of the new processes especially for low volume products in which the mask set is a large percentage of the total cost. For that reason there has been a strong incentive to develop technologies like Directed Self Assembly (DSA), EUV or E-beam direct write to reduce the total number of masks needed in a new technology node. Because of the nature of the technology, DSA cylinder graphoepitaxy only allows single-size holes in a single patterning approach. However, by integrating DSA and MP into a hybrid DSA-MP process, it is possible to come up with decomposition approaches that increase the design flexibility, allowing different size holes or bar structures by independently changing the process for every patterning step. A simple approach to integrate multi-patterning with DSA is to perform DSA grouping and MP decomposition in sequence whether it is: grouping-then-decomposition or decomposition-then-grouping; and each of the two sequences has its pros and cons. However, this paper describes why these intuitive approaches do not produce results of acceptable quality from the point of view of design compliance and we highlight the need for custom DSA-aware MP algorithms.
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