Predicting mask distortion, clogging and pattern transfer for stencil lithography

One of the ultimate tasks for stencil lithography is the ability to fabricate arrays of structures with controlled dimensions on the nanometer scale precisely positioned on a suitable surface. The race to shrink feature sizes requires the limits of conventional lithography to be extended to high-throughput, low cost, reliable and well-controlled processes of which stencilling is a promising candidate for nanoscale applications. Identifying, predicting and overcoming issues accompanying nanostencil lithography is critical to the successful and timely development of this technique for a wide range of potential applications. This paper addresses phenomena associated with stencil nanopatterning and presents the results of modelling and simulation studies for predicting the deleterious effects of mask distortion and clogging during pattern transfer. It is shown that degrading effects of stress-induced deformation of stencils can be dealt with via optimal design of corrugation structures which in turn reduce stencil deformation and significantly improves pattern definition. Modelling results are validated by comparison to experiment. The corrugation structures can be used to define practical design rules for fabrication of stable large area (''full scale'') purpose-designed stencil membranes. The accurate modelling of the clogging phenomenon combined with gradually evolving stencil deformation, also presented in the paper, can be used for prediction of pattern distortion, to calculate maximum thickness of a deposited layer and/or for prediction of the stencil lifetime.

[1]  Roxann L. Engelstad,et al.  Equivalent modeling techniques for predicting pattern transfer in EPL masks , 2001 .

[2]  Klavs F. Jensen,et al.  Modeling of metal thin film growth: Linking angstrom-scale molecular dynamics results to micron-scale film topographies , 2000 .

[3]  Roxann L. Engelstad,et al.  Mask distortion issues for next-generation lithography , 2003 .

[4]  J. Sader,et al.  Method for the calibration of atomic force microscope cantilevers , 1995 .

[5]  Xin Zhang,et al.  Intrinsic stress generation and relaxation of plasma-enhanced chemical vapor deposited oxide during deposition and subsequent thermal cycling , 2003 .

[6]  R. Glang,et al.  Handbook of Thin Film Technology , 1970 .

[7]  D. W. Hoffman,et al.  Stress-related effects in thin films , 1989 .

[8]  Jürgen Brugger,et al.  Simulation Study on Mechanical Stabilization of MEMS Stencils for Nanolithography , 2005 .

[9]  Ann Witvrouw,et al.  Determination of stress profile and optimization of stress gradient in PECVD poly-SiGe films , 2005 .

[10]  Scheffler,et al.  Ab initio calculations of energies and self-diffusion on flat and stepped surfaces of Al and their implications on crystal growth. , 1996, Physical review. B, Condensed matter.

[11]  Jurriaan Huskens,et al.  Shadow-mask evaporation through monolayer-modified nanostencils , 2002 .

[12]  Jurriaan Huskens,et al.  Self‐Assembled Monolayer Coatings on Nanostencils for the Reduction of Materials Adhesion , 2003 .

[13]  Kazumichi Suzuki,et al.  Mean Atomic Velocities of Uranium, Titanium and Copper during Electron Beam Evaporation , 1992 .

[14]  M. A. Angadi,et al.  DESIGN NOTE: Young's modulus of thin films using a simplified vibrating reed method , 1990 .

[15]  Jürgen Brugger,et al.  Deep-ultraviolet–microelectromechanical systems stencils for high-throughput resistless patterning of mesoscopic structures , 2004 .

[16]  Roxann L. Engelstad,et al.  Evaluation of intrinsic film stress distributions from induced substrate deformation , 2005 .

[17]  Marc A. F. van den Boogaart,et al.  Corrugated membranes for improved pattern definition with micro/nanostencil lithography , 2006 .

[18]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[19]  Jaroslav Mackerle,et al.  Nanomaterials, nanomechanics and finite elements: a bibliography (1994–2004) , 2004 .

[20]  Dae-Joon Kang,et al.  Dynamic shadow mask technique: a universal tool for nanoscience. , 2005, Nano letters.

[21]  Alfred Ludwig,et al.  MEMS tools for combinatorial materials processing and high-throughput characterization , 2004 .

[22]  M. Ohring.  The Materials Science of Thin Films , 1991 .

[23]  Roxann L. Engelstad,et al.  Stress relief structures for ion-beam projection lithography masks , 1999 .

[24]  Daniel C. Ralph,et al.  Nanofabrication using a stencil mask , 1999 .

[25]  Wei Zhao,et al.  Nanofabrication using nanotranslated stencil masks and lift off , 2004 .

[26]  Roxann L. Engelstad,et al.  Modeling pattern transfer in ion-beam lithography masks , 2000 .

[27]  W. Fang,et al.  Comments on measuring thin-film stresses using bi-layer micromachined beams , 1995 .

[28]  H. Hillmer,et al.  Stress investigation of PECVD dielectric layers for advanced optical MEMS , 2004 .

[29]  Peter Williams,et al.  Quantitative surface stress measurements using a microcantilever , 2001 .

[30]  J. Groves.  Directed vapor deposition , 1998 .