Dr. Jesper Sallander Profile

Dr. Jesper Sallander

at Mycronic AB

SPIE Involvement:

Author

Publications (2)

Proceedings Article | 20 October 2006 Paper

Improved photomask accuracy with a high-productivity DUV laser pattern generator

Thomas Öström, Jonas Måhlén, Andrzej Karawajczyk, Mats Rosling, Per Carlqvist, Per Askebjer, Tord Karlin, Jesper Sallander, Anders Österberg

Proceedings Volume 6349, 63490Y (2006) https://doi.org/10.1117/12.686196

KEYWORDS: Photomasks, Spatial light modulators, Neodymium, Calibration, Deep ultraviolet, Image enhancement, Electron beam lithography, Raster graphics, Control systems, Optical lithography

Read Abstract +

A strategy for sub-100 nm technology nodes is to maximize the use of high-speed deep-UV laser pattern generators, reserving e-beam tools for the most critical photomask layers. With a 248 nm excimer laser and 0.82 NA projection optics, the Sigma7500 increases the application space of laser pattern generators. A programmable spatial light modulator (SLM) is imaged with partially coherent optics to compose the photomask pattern. Image profiles are enhanced with phase shifting in the pattern generator, and features below 200 nm are reliably printed. The Sigma7500 extends the SLM-based architecture with improvements to CD uniformity and placement accuracy, resulting from an error budget-based methodology. Among these improvements is a stiffer focus stage design with digital servos, resulting in improved focus stability. Tighter climate controls and improved dose control reduce drift during mask patterning. As a result, global composite CD uniformity below 5 nm (3σ) has been demonstrated, with placement accuracy below 10 nm (3σ) across the mask. Self-calibration methods are used to optimize and monitor system performance, reducing the need to print test plates. The SLM calibration camera views programmed test patterns, making it possible to evaluate image metrics such as CD uniformity and line edge roughness. The camera is also used to characterize image placement over the optical field. A feature called ProcessEqualizer^TM has been developed to correct long-range CD errors arising from process effects on production photomasks. Mask data is sized in real time to compensate for pattern-dependent errors related to local pattern density, as well as for systematic pattern-independent errors such as radial CD signatures. Corrections are made in the pixel domain in the advanced adjustments processor, which also performs global biasing, stamp distortion compensation, and corner enhancement. In the Sigma7500, the mask pattern is imaged with full edge addressability in each writing pass, providing the means of additionally improving write time by reducing the number of exposure passes. Photomask write time is generally under two hours in the 2-pass mode, compared to three hours with 4-pass writing. With a through-the-lens alignment system and both grid matching and pattern matching capabilities, the tool is also suitable for 2^nd layer patterning in advanced PSM applications. Improvements in alignment algorithms and writing accuracy have resulted in first-to-second level overlay below 15 nm (mean+3σ).

Proceedings Article | 11 March 2002 Paper

Pattern generation with SLM imaging

Torbjoern Sandstrom, Per Askebjer, Jesper Sallander, Raoul Zerne, Andrzej Karawajczyk

Proceedings Volume 4562, (2002) https://doi.org/10.1117/12.458312

KEYWORDS: Spatial light modulators, Mirrors, Calibration, Photomasks, Micromirrors, Imaging systems, Analog electronics, Optics manufacturing, Control systems, Image acquisition

Read Abstract +

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years