76401s

Page 1

The impact of resist model on mask 3D simulation accuracy beyond 40nm node memory patterns Kao-Tun Chena, Shin-Shing Yeha, Ya-Hsuan Hsieha, Jun-Cheng Nelson Lai a, Stewart A. Robertsonb, John J. Biafore b, Sanjay Kapasi b , Arthur Lin b a

b

Powerchip Semiconductor Corp., No. 12 Li-Hsin RD, Hsinchu, Taiwan KLA-Tencor Corp., 8834 N. Capitol of Texas Highway, Austin, TX 78759, USA ABSTRACT

Beyond 40nm lithography node, mask topograpy is important in litho process. The rigorous EMF simulation should be applied but cost huge time. In this work, we compared experiment data with aerial images of thin and thick mask models to find patterns which are sensitive to mask topological effects and need rigorous EMF simulations. Furthur more, full physical and simplified lumped (LPM) resist models were calibrated for both 2D and 3D mask models. The accuracy of CD prediction and run-time are listed to gauge the most efficient simulation. Although a full physical resist model mimics the behavior of a resist material with rigor, the required iterative calculations can result in an excessive execution time penalty, even when simulating a simple pattern. Simplified resist models provide a compromise between computational speed and accuracy. The most efficient simulation approach (i.e. accurate prediction of wafer results with minimum execution time) will have an important position in mask 3D simulation. Keywords: EMF, 3D mask, Mask topography, Lumped parameter resist model, Full physical calibrated resist model

1. INTRODUCTION In ArF immersion process where mask pattern pitch (3X and 2X nodes) is many times smaller than exposure wavelength where strong RET and high NA are required. The light diffraction can not be correctly predicted by the Kirchhoff approximation mask model (or thin mask model) – as most frequently used in many imaging simulations today. Precise and accurate forecasting of the wafer pattern requires rigorous electromagnetic field analysis (EMF or 3D mask mode) which fully considered mask topography effects [1]. Many studies have indicated significant differences in patterning prediction between Kirchhoff approximations and 3D mask models[2][3][4]. Besides the difference of aerial image, ArF resist kinetics also play an important role which impacts the real image

Optical Microlithography XXIII, edited by Mircea V. Dusa, Will Conley, Proc. of SPIE Vol. 7640, 76401S · © 2010 SPIE · CCC code: 0277-786X/10/$18 · doi: 10.1117/12.846010

Proc. of SPIE Vol. 7640 76401S-1 Downloaded from SPIE Digital Library on 04 Mar 2010 to 192.146.1.254. Terms of Use: http://spiedl.org/terms


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.