Necessity of chemical edge bead removal in modern-day lithographic processing

Jekauc, Igor; Watt, Michael; Hornsmith, Trip; Tiffany, Jason E.

doi:10.1117/12.535268

Cited by 7 publications

(3 citation statements)

References 1 publication

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“…Consequently, special techniques have been developed for removing the edge-bead. 1 In the early days of semiconductor lithography, the edge-bead was large. During investigations into the impact of the shape of the wafer edge on edge-bead it was found that beveled wafer edges resulted in smaller edge-bead.…”

Section: The Practical Eramentioning

confidence: 99%

Evolution in the concentration of activities in lithography

Levinson

2016

SPIE Proceedings

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From a perusal of the proceedings of the SPIE Advanced Lithography Symposium, the progression of new concepts in lithographic technology can be seen. A new idea first appears in a few papers, and over time, there is an increase in the number of papers on the same topic. Eventually the method becomes commonplace, and the number of papers on the topic declines, as the idea becomes part of our industry's working knowledge. For example, one or two papers on resolution enhancement techniques (RETs) appeared in the proceedings of the Optical Microlithography Conference in 1989 and 1990. By 1994, the total number of papers had increased to 35. Early lithographers focused on practical issues, such as adhesion promotion and resist edge bead. The introduction of simulation software brought on the next era of lithography. This was followed by a period of time in which RETs were developed and brought to maturity. The introduction of optical proximity corrections (OPC) initiated the next major era of lithography. The traditional path for scaling by using shorter wavelengths, decreasing k 1 and increasing numerical aperture has given way to the current era of optical multiple patterning and lithography-design co-optimization. There has been sufficient activity in EUV lithography R&D to justify a separate EUV Lithography Conference as part of the annual Advanced Lithography Symposium. Each era builds on the cumulative knowledge gained previously. Over time, there have been parallel developments in optics, exposure tools, resist, metrology and mask technology, many of which were associated with changes in the wavelength of light used for leading-edge lithography.

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Section: The Practical Eramentioning

confidence: 99%

Evolution in the concentration of activities in lithography

Levinson

2016

SPIE Proceedings

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“…The alignment problem of wafer center is a significant and critical topic in semiconductor manufacturing processing because it affects coating performance, chemical edge bead removal (EBR), and the backside rinse steps for lithographic applications [ 1 ]. Its effect increases when the semiconductor process enters the era of deep submicron meter (below 20 nm), e.g., EUV process.…”

Section: Introductionmentioning

confidence: 99%

Wafer Center Alignment System of Transfer Robot Based on Reduced Number of Sensors

Kim¹

2022

Sensors

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This brief presents a wafer alignment algorithm with reduced sensor number that obtains the relative distance of the wafer center and the robot hand. By `reduced number’, in spite of smaller number of sensors than the conventional method, we mean an improved method which achieves the similar results to pre-existing algorithms. Indeed, it can be designed with only three sensor data, less than four sensors of the conventional algorithm. Thus, some advantages of the proposed alignment algorithm include that it can be designed with low cost and less computing power. The proposed alignment algorithm is applied to a transfer robot for coater/developer system in semiconductor processing for verifying the performance of the method. The performance of the proposed method is validated by both simulation and experimental results.

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“…Edge beads tend to be relatively thin (<1 µm) and narrow (<1 mm) for low-viscosity (~1 mPa s) photoresists spin-coated at the routine rotation speeds (~3000-5000 rpm) employed to achieve film thicknesses in the 0.1-10 µm range. In this case, it is a relatively simple task to remove such edge beads using higher spin speed [12], appropriate solvents [29], and other methods [30] making use of modern commercial spin coaters. However, for thicker liquid films, obtained at low spin speeds and/or using high viscosity products, matters are different.…”

Section: Introductionmentioning

confidence: 99%

The limits of edge bead planarization and surface levelling in spin-coated liquid films

Arscott

2020

J. Micromech. Microeng.

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A model is presented here to predict fluid reflow in a viscous liquid film having time-dependent physical properties. The model is applied to the practical example of the reflow planarization (surface levelling) of 'edge bead' features resulting from the spin coating process. During the reflow planarization of edge beads, the physical properties (surface tension, density and viscosity) of the spin-coated liquid can change over time for several reasons e.g. temperature change, solvent loss, and chemical reaction. The model is compared to experimental findings obtained using two spin-coated viscous liquid films: a drying photoresist (SU-8) and a curing elastomer (polydimethylsiloxane/PDMS). The former reveals the competition between reflow planarization and solvent loss-the latter reveals competition between reflow planarization and polymerization. It is demonstrated that the changing physical properties of the spincoated viscous liquid, especially the viscosity which can change by orders of magnitudes during these processes, impose limitations on the ultimate achievable practical planarization of the film.

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Necessity of chemical edge bead removal in modern-day lithographic processing

Cited by 7 publications

References 1 publication

Evolution in the concentration of activities in lithography

Evolution in the concentration of activities in lithography

Wafer Center Alignment System of Transfer Robot Based on Reduced Number of Sensors

The limits of edge bead planarization and surface levelling in spin-coated liquid films

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