Sentaurus Lithography 

Lithography simulation for accelerated process development 

Sentaurus Lithography covers a wide range of applications in optical, immersion, extreme ultraviolet (EUV) and electron beam (e-beam) lithography, allowing predictive modeling and thorough analysis of fundamental effects. The simulator covers a wide range of applications in optical, immersion, extreme ultraviolet (EUV) and electron beam (e-beam) lithography, allowing predictive modeling and thorough analysis of fundamental effects. The integration of Sentaurus Lithography with Sentaurus Topography allows seamless modeling of complex technologies such as double patterning. The interfaces of Sentaurus Lithography to Synopsys applications in the area of design and mask synthesis accelerate the generation of OPC models, minimizing process variability.

 

Technology simulation plays an invaluable role in the field of advanced process development and optimization. Simulation effectively minimizes experimental engineering lots and short-loop experiments, resulting in accelerated process development, considerable cost savings, and a faster time-to-market.

Sentaurus Lithography provides all computational lithography capabilities necessary to enable engineers making precise and reliable predictions on the performance of lithography processes and strategies. Individual modules of Sentaurus Lithography address challenges in all relevant areas.

Benefits
  • Explore major technology options for manufacturability
    • Immersion lithography over arbitrary wafer topography
    • EUV lithography
    • Double patterning techniques
  • Optimize process windows analyze process variability
  • Guide experiments for efficient process development
  • Evaluate impact of restrictive design rules on resist contours

Sentaurus Lithography offers an intuitive graphical user interface as well as extensive scripting capabilities that allow users to set up and automate complex simulation scenarios, and support the integration into customized workflows.

Sentaurus Lithography is designed to benefit from state-of-the-art hardware resources. The MP option enables parallel processing on SMP hardware systems (multi-threading). Sentaurus Lithography running on high performance compute clusters provides the fastest, most scalable and cost effective computation lithography solution available today.

    Sentaurus Lithography - Optical Module
    The optical module allows state-of-the-art simulation of the optical imaging process for evaluation and optimization purposes. It supports the analysis of complex source shapes, broadband exposures, optical effects caused by projection lens aberrations and polarization, noise, as well as multiple exposure techniques for resolution enhancement - in both dry and immersion lithography. A 3D resist model provides high predictive power to all kinds of simulation tasks.

    Mask Topography (MT) Module (add-on module to the Optical Module)
    If dimensions on the mask level approach the wavelength of the exposure light, the electromagnetic field (EMF) propagating through the mask stack must be determined rigorously by solving Maxwell’s equations in all three dimensions. The MT module allows detailed studies of variances that are introduced by the mask-making process, such as corner rounding and sidewall angles.

    Wafer Topography (WT) Module (add-on module to the Optical Module)
    Upcoming process integration technologies like double patterning require accurate simulation of critical imaging layers on pre-patterned surfaces. Sentaurus Lithography models wafer topography through rigorous calculation of the electric field in the topographic stack. In combination with Sentaurus Topography, a complete double patterning flow can be realized, allowing parameter variations across the different process steps.

    The Optical module requires the TCAD Sentaurus Lithography Base module for stand-alone operation. This module supports comprehensive functionality for parametric analysis, which can be used for largely automatic process window optimization and resist model parameter calibration.

    Extreme Ultra Violet Lithography Simulation – EUV Module
    EUV lithography is considered the most viable solution for printing the critical features associated with the 22nm technology node. It becomes increasingly necessary for all potential EUV users to understand the origin of the sources of CD variations to develop appropriate compensation strategies.

    The simulation of EUV lithographic processes can be performed by the EUV module. A key component of the simulation is the accurate EMF computation in the vicinity of the multilayer mask. The reflective nature of the EUV mask requires nontelecentric illumination, which will cause pattern shift and shadowing effects on the wafer. Imaging itself is very sensitive to the scatter due to the short exposure wavelength, which results in a significant flare level. Moreover, defects in the absorber and the multilayer structure can impact imaging performance.

    Simulation offers the opportunity to separate the impact of, for example, illumination, mask topography, pattern orientation, and flare and to determine their significance for manufacturing the actual device, and therefore allows developing effective compensation strategies.

    The EUV module requires the TCAD Sentaurus Lithography Base module for stand-alone operation.

    Overview
    Sentaurus Lithography PWA (PWA) is a process window analyzer. It is a comprehensive and powerful tool for visualizing and analyzing simulation results or experimental data, for example, obtained by critical dimension (CD) metrology measurements. From input data generally obtained from a focus-exposure matrix, PWA determines key measures that characterize the performance of the lithographic process, such as process window size or exposure latitude. Multiple datasets are analyzed individually, and the overlapping (or common) process window is determined.

    PWA is a stand-alone software application designed specifically towards the analysis of CD metrology measurement data. All aspects of process window analysis functionality are also available within the Base Module of Sentaurus Lithography for standard evaluations of simulation results.

    Benefits
    • Enable fast and effective qualification of lithography process by flexible analysis of process windows and their properties
    • Support conditioning of measurement data (e.g. by smoothing or flyer elimination) to improve input data quality for subsequent data fitting in order to obtain more robust models (resist model parameter, OPC models, etc.)
    • Enable effective visualization of large and complex data sets

    Electron-Beam Lithography Simulation – E-beam Module
    Traditionally, e-beam lithography is used to define the pattern within the absorber layer on photomasks. Moreover, it can be applied to direct-write device-specific structures on the wafer level (maskless lithography), offering an alternative to EUV lithography or complex optical lithography processes such as double patterning.

    The e-beam module of Sentaurus Lithography supports the simulation of both wafer direct-write as well as mask-writing applications. Electron-scattering processes in the resist and wafer or the mask stack determine the corresponding point spread functions (PSFs); the implemented models support both low (< 10 keV) as well as high electron energies (20 – 50 keV). From the total energy deposited in the resist film, the resulting resist profiles can be determined.

    A key application for e-beam lithography simulation is the development and evaluation of proximity correction strategies, even at a very early state of the exposure tool development. This reduces the dependency on the hardware itself and improves development cycle times.

    The e-beam module requires the TCAD Sentaurus Lithography Base module for stand-alone operation.