Lens aberration control for fine patterning with PSM

Kudo, Takehito; Hirukawa, Shigeru; Nakashima, Toshiharu; Matsumoto, Koichí

doi:10.1117/12.435769

Cited by 2 publications

(2 citation statements)

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“…This type of analysis has been reported and discussed in detail in several previous papers 6,7,8,9 , and is most typically referred to as the Zernike Sensitivity Method (ZSM). The purpose of such an analysis in the early stages of an optimization project is to shed light on which aberrations show the largest impact upon the CD/Focus (and analogously the Image Shift/Focus) behavior.…”

Section: Aberration Sensitivitymentioning

confidence: 97%

Application of in-situ aberration measurements to pattern-specific imaging optimization

Slonaker

Chung²

2003

SPIE Proceedings

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With the advent of in-situ aberration measurement, users may now gather a 'snapshot' of a given lens' aberration fingerprint following installation of the exposure tool in their fab. This paper will detail how this information may be used as input data into an optimization routine whose final output is a set of lens adjustments that will yield improved imaging performance. It will be shown that a lens with many reliable degrees of adjustment freedom can offer a wide range of optimization options.For example, for some process levels, a fixed focus latitude requirement is well defined, and it often is desirable to optimize the CD distribution over that available focus range. For other levels, there may be a strict 'image shift' requirement over a specified focus range. In general, such optimization should include some combination of imaging performance targets.Within some limits, the user may specify the imaging performance priorities, and an optimization routine can be executed. The optimization routine may in principle allow manipulation of all available lens adjustment degrees of freedom, ending with a lens adjustment prescription that delivers the optimum result in terms of the user-specified priorities.Examples of such optimization, showing the expected improvement in the imaging performance, will be presented through image simulation results.

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Section: Aberration Sensitivitymentioning

confidence: 97%

Application of in-situ aberration measurements to pattern-specific imaging optimization

Slonaker

Chung²

2003

SPIE Proceedings

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“…This CD error will increase significantly when feature size continues to shrink and will dramatically affect across slit CD uniformity, OPC performance and toolto-tool matching capability. More importantly, spherical aberration is becoming one of the most critical lens aberrations for next node technology where small feature sizes and illumination sigmas are dominant, such as alt-PSM applications in 90nm and 65 nm nodes [3,4,5]. Spherical aberration has been studied by using a variety of methods such as Litel Insitu Interferometer (ISI) [6], Pinhole aperture method [7] and phase measurement interferometer (PMI) [8,15].…”

Section: I Introductionmentioning

confidence: 99%

Evaluating scanner lens spherical aberration using scatterometer

et al. 2003

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Lens spherical error is an important lens aberration used to characterize lens quality and also has a significant contribution to across chip line width variation (ACLV). It also impacts tool-to-tool matching efforts especially when the optical lithography approaches sub-half wavelength geometry. Traditionally, spherical error is measured by using CD SEM with known drawbacks of poor accuracy and long cycle time. At Texas Instruments, an in-house scatterometer-based lens fingerprinting technique(ScatterLith) performs this tedious job accurately and quickly. This paper presents across slit spherical aberration signatures for ArF scanners collected using this method. The technique can successfully correlate these signatures with Litel lens aberration data and Nikon OCD data for spherical aberration errors as small as 10 mλ . ACLV contributions from such small spherical errors can be quantified using this method. This provides the lithographer with an important tool to evaluate, qualify and match advanced scanners to improve across chip line width variation control.

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Lens aberration control for fine patterning with PSM

Cited by 2 publications

References 0 publications

Application of in-situ aberration measurements to pattern-specific imaging optimization

Application of in-situ aberration measurements to pattern-specific imaging optimization

Evaluating scanner lens spherical aberration using scatterometer

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