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Record W2482900148 · doi:10.1117/3.601520.ch10

The Limits of Optical Lithography

2009· book-chapter· en· W2482900148 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueSPIE eBooks · 2009
Typebook-chapter
Languageen
FieldEngineering
TopicAdvancements in Photolithography Techniques
Canadian institutionsAdvanced Micro Devices (Canada)
Fundersnot available
KeywordsLithographyComputational lithographyStepperExtreme ultraviolet lithographyNext-generation lithographyOpticsFocus (optics)Resolution (logic)PhotolithographyX-ray lithographyImmersion lithographyPhysicsResistElectron-beam lithographyComputer scienceNanotechnologyMaterials scienceArtificial intelligence

Abstract

fetched live from OpenAlex

In 1979, Electronics magazine reported that stepper lithography would be a passing fancy superseded by direct-write electron beam lithography by the year 1985. It was admitted in a follow-up article, written for that same magazine in 1985, that the demise of optical lithography had been predicted prematurely and that it would take until 1994 for shipments of optical wafer steppers to be of lower volume than those of x-ray step-and-repeat systems. It was expected that optical lithography, once it reached its resolution limit of 0.5 μm, would need to be replaced. Both pronouncements were based upon accepted expert opinion. This book has been written in the year 2005, and optical lithography is still going strong, but there are a number of programs dedicated to developing alternative lithography techniques. It is worth reviewing earlier arguments as to why optical lithography was nearing its end of life, and what arguments are being presented today to justify billions of dollars of investment in new lithography techniques. 10.1 The diffraction limit The argument that optical lithography has limited resolution is based upon Rayleigh's scaling laws of resolution and depth-of-focus. From Chapter 2, resolution is given by Resolution=k 1 λ NA , where the prefactors of Eqs. (2.4) and (2.7) are replaced by a general factor k 1 . Similarly, the expression for depth-of-focus can be written as Depth-of-focus=±k 2 λ NA 2 . It has long been recognized that Rayleigh's and equivalent expressions are inexact predictors of resolution, but do correctly capture the trends associated with wavelengths and numerical apertures. Other factors, such as the resist process, are captured by the coefficients k 1 and k 2 . In 1979, the state-of-the-art lens had a resolution of 1.25 μm, a ± 0.75-μm depth-of-focus, a numerical aperture of 0.28, and imaged at the mercury g-line. This produced values of 0.80 and 0.13 for k 1 and k 2 , respectively. With these values for the coefficients in Eqs. (10.1) and (10.2), the numerical aperture of a g-line lens capable of producing 0.8-μm features would be 0.44, with a ± 0.3-μm depth-of-focus.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Other · Consensus signal: Other
Teacher disagreement score0.796
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.016
GPT teacher head0.247
Teacher spread0.231 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it