Innovative metrology for wafer edge defectivity in immersion lithography

Pollentier, Ivan; Iwamoto, Fumio; Kocsis, Michael; Somanchi, A.; Burkeen, F.; Vedula, S.

doi:10.1117/12.713347

Cited by 3 publications

(3 citation statements)

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“…Defectivity performance in immersion lithography is a key factor to obtain a high yield and it is strongly affected by wafer edge conditions [1][2][3][4][5]. We have shown the defectivity results with wafer edge shape variation [5].…”

Section: Introductionmentioning

confidence: 94%

Defectivity improvement by modified wafer edge treatment in immersion lithography

et al. 2009

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ArF immersion lithography has reached mass production stage for 55-40 nm node devices. Especially, defectivity performance at wafer edge in immersion lithography has been recently discussed in detail, because its controllability is a key factor to obtain high yield. We have already reported that defectivity was strongly affected by the wafer edge shape and long edge wafer showed better defectivity performance than short one. We also found remaining flakes or particles at wafer edge after coating were easy to be peeled off on short edge wafer during exposure and these peeled flakes or particles were most suspected candidate which induces bridging defects. Therefore it is important to prevent generating such peeled flakes or particles for good defectivity in immersion lithography. In this paper, we will show the defectivity results of various kinds of wafers which have different wafer edge shapes (long,short and full-round) and diameters to investigate the effect of wafer edge geometry on defectivity performance in detail. Furthermore, we investigated the relation of an edge removal method and the defectivity with referring bevel inspection results at each coating step. We confirmed that the modified edge removal method well improved the defectivity performance. We will discuss them based on the latest data and propose the most suitable technique to remove the wafer edge particles before immersion exposure.

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Section: Introductionmentioning

confidence: 94%

Defectivity improvement by modified wafer edge treatment in immersion lithography

et al. 2009

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“…During immersion litho the lens moves rapidly over the wafer surface with a fluid filling the gap between the lens and the surface. The fluid can undergo turbulent flow with capillary forces on the trailing edge of the meniscus peeling off particles from the edge of the wafer (14) (15). Edge flakes (residues of surface films on the edge) may be transported by the turbulent flow of the immersion fluid from the edge inwards.…”

Section: Semiconductor Wafer Challengesmentioning

confidence: 99%

Challenges in Wafering Processes for Semiconductor and Solar Wafers

Erk

2009

ECS Trans.

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The transition from 50 to 32nm silicon technologies will place strict requirements on semiconductor wafer flatness and nanotopography. Site flatness and shape capability at the edge must improve, as well as the edge characteristics (finish and shape) and quality. As diameter increases from 300 to 450mm, thickness does not scale with wafer diameter leading to a relatively less rigid wafer. This adds additional burden to the task of capability improvement.To be competitive with alternative energy technologies solar wafer manufacture is focused on cost reduction and capability improvement to enable cell-processing optimization.The challenge is to cut thinner wafers with reduced depth of damage, lower TTV and with no micro-cracks. Slicing kerf reduction and abrasive / silicon recovery are options to further reduce cost.

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“…Especially defectivity performance at wafer edge in immersion lithography has been recently discussed in detail [1,2], because its controllability is a key factor to obtain high yield. Besides the effective edge bead removal (EBR) method, wafer edge geometry itself, for example edge roll-off (ERO), also gives strong effects on basic performance of immersion scanner.…”

Section: Introductionmentioning

confidence: 99%

Focus, dynamics, and defectivity performance at wafer edge in immersion lithography

Tamura

Onoda

Fujita

et al. 2008

Optical Microlithography XXI

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We evaluate several types of wafers and investigate the effect of wafer edge geometry on focus, dynamics and defectivity performance in ArF immersion lithography. Wafer edge geometry includes both edge shape (e.g. short, long, full round etc.) and edge roll-off (ERO) here. We found that focus accuracy at wafer edge depends on ERO, especially on ZDD (Z double derivative) and if we use the specified wafer which has low ZDD value, it keeps same good focus accuracy at the edge area as the one at the wafer center area. Dynamics (stage synchronization accuracy) was independent of wafer diameter, thickness and edge geometry. We also found that defectivity was strongly dependent on the edge shape. More bridging defects were found on the short edge wafer than the long edge wafer. This is related with wafer edge conditions after coating and during exposure.

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Innovative metrology for wafer edge defectivity in immersion lithography

Cited by 3 publications

References 0 publications

Defectivity improvement by modified wafer edge treatment in immersion lithography

Defectivity improvement by modified wafer edge treatment in immersion lithography

Challenges in Wafering Processes for Semiconductor and Solar Wafers

Focus, dynamics, and defectivity performance at wafer edge in immersion lithography

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