Reticle heating feed-forward control (RHC2) on NXT:1980Di immersion scanner for enhanced on-product overlay

Kim, Young Ha; Jang, Jaesung; Lee, Byeong Soo; Hwang, Hyunwoo; Nam, Youngsun; Kong, Jeong-Heung; Kang, Yongjoon; Jang, Seyeon; Paarhuis, Bart; Wielen, Jeroen van der; Moest, Barry; Jongen, Joris; Weichselbaum, Stefan; Verbeek, Niek; Stavenga, Marco; Graaf, Roelof de; Droste, Richard

doi:10.1117/12.2259792

Cited by 1 publication

(2 citation statements)

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“…As shown in Figure 2-1, two wafer stages work in parallel on the Twinscan platform. One stage is on the measure side, performing the wafer alignment by using the alignment sensor to measure the alignment marks on the wafer, while the other stage is on the exposure side, performing lens correction and reticle alignment before exposing each wafer [4]. Besides the controlling system in a scanner, additional process correction could be applied on a lot-basis to further fine-tune the exposure grid through the factory automation system.…”

Section: How To Control the Overlay Through Scannersmentioning

confidence: 99%

“…From steps [2] and step [4], we can calculate the new subsequent layer`s overlay based on the new grids of upper-layer OVL marks and under-layer OVL marks with the equation: New OVL = POR OVL + (∆AL Modeled) -∆TC. Depending on the different process trees between the subsequent layer and the current layer, the cross-layer overlay simulation method needs an adjustment.…”

Section: ∆𝐴𝐿 𝑚𝑜𝑑𝑒𝑙𝑒𝑑 𝑔𝑟𝑖𝑑 = ( 𝑁𝑒𝑤 𝐴𝐿 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑚𝑒𝑛𝑡 𝑔𝑟𝑖𝑑 𝑁𝑒𝑤 𝐴𝐿 𝑚𝑜𝑑𝑒𝑙 ) ...mentioning

confidence: 99%

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Advanced cross-layer overlay simulation with exposure grid re-calculation

Lu,

Tsou,

Demirer

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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In today's advanced semiconductor industry with the multitude of new products and device requirements, lithography process changes are inevitable and expected due to tighter overlay specifications and the increasing influence of process effects. To minimize the overlay impact from the wafer-to-wafer and lot-to-lot variation, lithography engineers often need to adjust wafer alignment and overlay strategies to optimize product yield. Overlay simulation methods are often used to estimate if new alignment and/or overlay strategies can help achieve better overlay performance. By removing the old corrections from the original alignment and overlay data, and then applying new corrections, the overlay performance can be readily predicted, saving significant time. However, available software suites only simulate the current layer overlay. Overlay risks would therefore remain on subsequent layers without an effective simulation method to predict the impact resulting from changes to the alignment and/or overlay strategies on the current layer.In our study, we demonstrate a new method to simulate the overlay performance on the subsequent layers by re-calculating the current layer exposure grid. Our dataset has 3 layers: L0, L1, and L2. On L1 (current layer), we apply a new alignment model and overlay control strategy with a feedforward solution. Then, we re-calculate the exposure grid to generate a new (virtual) alignment and overlay dataset for L2 (following layer). Finally, we estimate the overlay impact on L2 with the new alignment and overlay dataset and summarize the benefits of this new cross-layer overlay simulation method.

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Section: How To Control the Overlay Through Scannersmentioning

confidence: 99%