Two-dimensional low pass filter model for die-level topography variation resulting from chemical mechanical polishing of ILD films

Tat Kwan Yu, Sejal Chheda, Judy Ko, Mark Roberton, Aykut Dengi, Ed Travis

Research output: Contribution to journalConference article

11 Scopus citations

Abstract

This paper presents a new two-dimensional (2-D) low pass filter model for the prediction of post- chemical-mechanical polishing (CMP) die level wafer topography variation caused by the interconnect metal density of a circuit layout. It is demonstrated that the local smoothing and planarization effects of an ILD polishing process can be characterized accurately (in the frequency domain) by a polynomial equation with a small number of fitted parameters. In this method, the design specific metal density patterns with millions of shapes are first captured in the frequency domain using a 2-D Fast Fourier Transform (FFT). A fitted low pass filter CMP model is then applied to filter/remove short range pattern variation. (Die level topography variations are not removed by CMP effectively). Finally, the post-CMP smoothed topography in the spatial domain is computed from inverse FFT. Model predictions and experimental data are compared in three examples a) a test structure, b) a die with shallow trench isolation c) cumulative topography of a die after ILD1, ILD2 and ILD3 polishing.

Original languageEnglish (US)
Pages (from-to)909-912
Number of pages4
JournalTechnical Digest - International Electron Devices Meeting
StatePublished - Dec 1 1999
Event1999 IEEE International Devices Meeting (IEDM) - Washington, DC, USA
Duration: Dec 5 1999Dec 8 1999

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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