Dependence of mask topography effects on pattern variation under hyper-NA lithography

Akiko Mimotogi; Masamitsu Itoh; Shoji Mimotogi; Kazuya Sato; Takashi Sato; Satoshi Tanaka; Soichi Inoue

doi:10.1117/12.793127

19 May 2008 Dependence of mask topography effects on pattern variation under hyper-NA lithography

Akiko Mimotogi, Masamitsu Itoh, Shoji Mimotogi, Kazuya Sato, Takashi Sato, Satoshi Tanaka, Soichi Inoue

Proceedings Volume 7028, Photomask and Next-Generation Lithography Mask Technology XV; 70283K (2008) https://doi.org/10.1117/12.793127
Event: Photomask and NGL Mask Technology XV, 2008, Yokohama, Japan

Abstract

The purpose of this work was to identify the specific effects of mask topography by analyzing in the Fourier domain. Our focus patterns extend from a simple contact hole (CH) with a fixed pitch and bias to ones that have a variety of different pitches and hole sizes. We also attempt to predict phases and amplitudes of diffraction on the pupil plane without a rigorous mask topography approximated model. Intensities of CH patterns are simulated using three mask models. We had determined that there are serious differences among the three mask models concerning the contrast of the intensity and the qualitative interpretation of the trend of contrast varies according to pitch and hole sizes. The mask topography effects can be classified into waveguide and shadowing effects simply by using the diffraction decomposition diagram. We clarify how much and when the mask topography influences imaging under hyper-NA lithography by the diagram. From 1D near-field phase distribution, it is clarified that phase distribution has also been decided by the MoSi width between holes so that waveguide effects are not only from hole but also from MoSi area. It has been determined that the influence of the real 3D structures of the mask under the hyper-NA condition cannot be disregarded. However, use of the rigorous EMF calculation costs much more and requires more time than using a non-EMF calculation. We have also clarified the mechanism of 3D mask effects based on the amplitude and the phase of the diffraction light in the Fourier-domain diagram and examined whether the 3D mask effects can be predicted by thin mask approximation (TMA) and found that once we have values of amplitude and phase of the 0th and the 1st diffraction in TMA, it will be possible to predict the values of the other pitch and the other hole size.

Citation Download Citation

Akiko Mimotogi, Masamitsu Itoh, Shoji Mimotogi, Kazuya Sato, Takashi Sato, Satoshi Tanaka, and Soichi Inoue "Dependence of mask topography effects on pattern variation under hyper-NA lithography", Proc. SPIE 7028, Photomask and Next-Generation Lithography Mask Technology XV, 70283K (19 May 2008); https://doi.org/10.1117/12.793127

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available