Papers by Shayak Banerjee
Frontiers in medicine, Mar 1, 2024
Proceedings of SPIE, Mar 17, 2011
Double exposure techniques are an economically viable method for extending the life of the curren... more Double exposure techniques are an economically viable method for extending the life of the current 193nm wavelength immersion lithography techniques into future generations of semiconductor scaling. One popular example of double exposure is the use of double dipole illumination, where the X and Y dipoles are separately optimized for vertical and horizontal features respectively. The primary challenge in such double
Proceedings of SPIE, Mar 17, 2011
Conventional resolution enhancement techniques (RET) are becoming increasingly inadequate at addr... more Conventional resolution enhancement techniques (RET) are becoming increasingly inadequate at addressing the challenges of subwavelength lithography. In particular, features show high sensitivity to process variation in low-k1 lithography. Process variation aware RETs such as process-window OPC are becoming increasingly important to guarantee high lithographic yield, but such techniques suffer from high runtime impact. An alternative to PWOPC is to perform
In this paper we describe the motivation, challenges, and design methods of miniaturizing UV Inde... more In this paper we describe the motivation, challenges, and design methods of miniaturizing UV Index radiometry into a wearable form factor. The UV Index is the standard metric to measure instantaneous UV exposure in a way that is relevant to the human skin. However, unlike FDA regulated sensors like the glucose sensor, there is a currently an absence of specifications for the performance of wearable UV Index radiometers. In this paper, we develop performance metrics based on accuracy and sensitivity, and further evaluate the performance of several commercially available UV Index wearable radiometers on the basis of these metrics. Comparisons to laboratory-grade equipment show that the Shade radiometer is the most accurate and the most sensitive commercially available wearable UV radiometer. Ethics statement: This paper does not describe research involving human or animal subjects and is therefore not subject to review by IRB or IACUC.
Acta dermato-venereologica, 2021
The use of sunscreens is considered to be protective against skin cancer. These products should b... more The use of sunscreens is considered to be protective against skin cancer. These products should be used appropriately and manufactured with a ultraviolet A:ultraviolet B ratio of 1:3 in order to be protective, or else, as shown in this study, sunscreen might increase the risk of melanoma. The use of sunscreens is recommended to limit the impact of sun exposure on the skin. The objective of this study was to examine the relationship between sunscreen sales and melanoma in 4 different countries with diverse sunscreen regulations. Data from publicly avail able databases were examined for Sweden, England, Australia, and the USA from 1999 to 2018. The association between incidence of melanoma and sunscreen sales was estimated using a generalized estimating equation, and modelling was used to predict melanoma cases. Incidence of melanoma was positively associated with sunscreen sales in England, Australia, and the USA, and negatively associated with sunscreen sales in Sweden. Growth rates in melanoma cases of 0.42%, 16.7%, 19.1% and 12.2% were predicted for Sweden, England, Australia, and the USA, respectively. The differences observed between England, Australia, and the USA, on the one hand, and Sweden, on the other hand, are consistent with the adoption of strong regulations requiring the use of ultraviolet A blocking agents in sunscreens.
Sixteenth ACM Conference on Recommender Systems, Sep 18, 2022
International Conference on Computer Aided Design, Nov 10, 2008
Conventional optical proximity correction (OPC) tools aim to minimize edge placement errors (EPE)... more Conventional optical proximity correction (OPC) tools aim to minimize edge placement errors (EPE) due to the optical and resist process by moving mask edges. However, in low-k1 lithography, especially at 45nm and beyond, printing perfect polygons is practically impossible to achieve. In addition, prohibitively high mask complexity is incurred, leading to high mask cost. Given the impossibility of perfect printing, we argue that aiming to reduce the error of electrical discrepancy between the ideal and the printed contours is a more reasonable strategy. In fact, we show that contours with non-minimal EPE may result in closer match to the desired electrical performance. Towards achieving this objective, we developed a new electrically driven OPC (ED-OPC) algorithm. The tool combines lithography simulation with accurate electrical modeling of resist contours to predict the on/off current through a transistor gate. The computation of mask edge movements is cast as a linear program based on optical and electrical sensitivities. The objective is to minimize the error in saturation current between printed and target shapes. This optimization is then solved with fast runtime. The results on industrial 45nm SOI layouts using high-NA immersion lithography models show up to a 5% improvement in accuracy of timing over conventional OPC. This is achieved at less than 26% runtime overheads, while also lowering mask complexity by up to 43%. The results confirm that better timing accuracy can be achieved despite larger edge placement error.
International Conference on Computer Aided Design, Nov 3, 2014
As nanometer technology advances, conventional OPC (Optical Proximity Correction) that minimizes ... more As nanometer technology advances, conventional OPC (Optical Proximity Correction) that minimizes the EPE (Edge Placement Error) at the nominal corner alone often leads to poor process window. To improve the mask printability across various process corners, process-window OPC optimizes EPE for multiple process corners, but often suffers long runtime, due to repeated lithographic simulations. This paper presents an efficient process-variation-aware mask optimization framework, namely PVOPC (Process-Variation OPC), to simultaneously minimize EPE and PV (Process-Variation) band with fast convergence. The PVOPC framework includes EPE-sensitivity-driven dynamic fragmentation, process-variation-aware EPE modeling, and post correction with three new EPE-converging techniques and a systematic sub-resolution assisted feature insertion algorithm. Experimental results show that our approach efficiently achieves high-quality EPE and PV band results.
Annales de Dermatologie et de Vénéréologie - FMC, 2021
Acta Dermato Venereologica, 2021
The use of sunscreens is considered to be protective against skin cancer. These products should b... more The use of sunscreens is considered to be protective against skin cancer. These products should be used appropriately and manufactured with a ultraviolet A:ultraviolet B ratio of 1:3 in order to be protective, or else, as shown in this study, sunscreen might increase the risk of melanoma. The use of sunscreens is recommended to limit the impact of sun exposure on the skin. The objective of this study was to examine the relationship between sunscreen sales and melanoma in 4 different countries with diverse sunscreen regulations. Data from publicly avail able databases were examined for Sweden, England, Australia, and the USA from 1999 to 2018. The association between incidence of melanoma and sunscreen sales was estimated using a generalized estimating equation, and modelling was used to predict melanoma cases. Incidence of melanoma was positively associated with sunscreen sales in England, Australia, and the USA, and negatively associated with sunscreen sales in Sweden. Growth rates in melanoma cases of 0.42%, 16.7%, 19.1% and 12.2% were predicted for Sweden, England, Australia, and the USA, respectively. The differences observed between England, Australia, and the USA, on the one hand, and Sweden, on the other hand, are consistent with the adoption of strong regulations requiring the use of ultraviolet A blocking agents in sunscreens.
2017 IEEE Life Sciences Conference (LSC), 2017
In this paper we describe the motivation, challenges, and design methods of miniaturizing UV Inde... more In this paper we describe the motivation, challenges, and design methods of miniaturizing UV Index radiometry into a wearable form factor. The UV Index is the standard metric to measure instantaneous UV exposure in a way that is relevant to the human skin. However, unlike FDA regulated sensors like the glucose sensor, there is a currently an absence of specifications for the performance of wearable UV Index radiometers. In this paper, we develop performance metrics based on accuracy and sensitivity, and further evaluate the performance of several commercially available UV Index wearable radiometers on the basis of these metrics. Comparisons to laboratory-grade equipment show that the Shade radiometer is the most accurate and the most sensitive commercially available wearable UV radiometer. Ethics statement: This paper does not describe research involving human or animal subjects and is therefore not subject to review by IRB or IACUC.
Semiconductor scaling has been largely driven by advancements in lithographic technologies. Howev... more Semiconductor scaling has been largely driven by advancements in lithographic technologies. However, the lack of a viable next generation lithography solution since the 180nm node has driven the industry to printing sub-wavelength features. This has led to rising manufacturing costs and diminishing chip yield. In traditional methodologies, manufacturing and design are relatively insulated, with a layout being the only means of communicating design intent to the foundry. In this dissertation, we describe several techniques which utilize electrical information to improve properties of manufactured structures. We aim to show that a bi-directional flow of information between design and manufacturing is key to increasing chip yield. In particular, we target the mask data preparation flow of lithography. We develop an electrically-driven optical proximity correction (ED-OPC) tool that performs electrical matching as opposed to geometric matching in order to achieve lower post-lithography delay error. We then demonstrate how to harness ED-OPC to compensate electrical variability arising from non-lithographic sources as well. We then describe a technique to manufacture circuits with less timing violations across the process window by using design-aware shape tolerances generated from timing information. Finally, we observe that local wiring has low impact on design properties and use this information to modify target wire shapes themselves in order to improve their manufacturability in the presence of process variations.
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2016
As nanometer technology advances, conventional optical proximity correction (OPC) that minimizes ... more As nanometer technology advances, conventional optical proximity correction (OPC) that minimizes the edge placement error (EPE) at the nominal process condition alone often leads to poor process windows. To improve the mask printability across various process corners, process-window OPC optimizes EPE for multiple process corners, but often suffers long runtime, due to repeated lithographic simulations. This paper presents an efficient process variation (PV)-aware mask optimization framework, namely PVOPC, to simultaneously minimize EPE and PV band with fast convergence. The PVOPC framework includes EPE-sensitivity-driven dynamic fragmentation, PV-aware EPE modeling, and correction with three new EPE-converging techniques and a systematic subresolution-assisted feature insertion algorithm. Experimental results show that our approach efficiently achieves high-quality EPE and PV band results.
International Symposium on Quality Electronic Design (ISQED), 2013
ABSTRACT Current technology scaling trends are changing the character of wire delay variability. ... more ABSTRACT Current technology scaling trends are changing the character of wire delay variability. The distribution of wire delay is asymmetric, with a long positive tail which can be as much as 2X longer than the negative tail. This is due to the geometry of these wires, where the aspect ratio is biased towards tall thin wire cross-sections, as well as manufacturing induced variations particularly from lithography. These trends are important for timing closure, whether done via corner-based or statistical analysis. In this paper, we explore these trends, demonstrate their impact in a modern 32nm CMOS design, and suggest ways in which this trend can be managed and reduced. Particularly, through physical synthesis optimization on industrial designs, we show how these trends/observations can be utilized to produce more reliable designs. As the interconnect scaling lags behind the device scaling, the importance of wire variability will grow further in the future technology nodes.
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Papers by Shayak Banerjee