Qualification of small alignment mark by on-product overlay performance

Ma, Jigang; Bijnen, F.G.C.; Hulsebos, Edo; Macht, L.; Tsiachris, Sotirios; Dai, Jin; Meulen, R. van der; Yu, Miao; Böcker, Paul; Kim, Junghwan; Kim, Hyun; Kim, Gwang-Gon; Lee, Joonseuk; Oh, Eungryong; Yeon, Hongbok; Kim, Young-Deuk; Jeong, Seung-Uk; Lee, Sang-Ho; Park, Chanha

doi:10.1117/12.2584618

Cited by 2 publications

(3 citation statements)

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“…The RBF alignment model is one of the functions in Overlay Optimizer 1 (OVO1) that can be applied in ASML Twinscan immersion systems. With the radial base function model and new anchor points distribution method for CPE6 re-modeling, the RBF alignment model could have a quite different overlay performance to the traditional HOWA3 model [5]. The RBF model was originally designed for better edge-fitting performance and to prevent over-correction, which easily occurred in the traditional HOWA3 model.…”

Section: Topic 2 (New Alignment Strategy On Layer 1)mentioning

confidence: 99%

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: Topic 2 (New Alignment Strategy On Layer 1)mentioning

confidence: 99%

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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“…On ASML scanners, Wafer Quality 15,16,17 (WQ), Alignment Position Deviation (APD) and Residual Overlay Performance Indicator (ROPI) 17 are typical figures of merit for alignment performance. The WQ is a metric for the amount of signal detected during an alignment mark scan.…”

Section: Experimental Conditionsmentioning

confidence: 99%

“…The WQ is a metric for the amount of signal detected during an alignment mark scan. while ROPI (Residual Overlay Performance Indicator) is the remaining residual of APD, after applying the corresponding alignment model 17 .…”

Section: Experimental Conditionsmentioning

confidence: 99%

Alignment and overlay through opaque metal layers

Carballo

Canga

Jehoul

et al. 2023

Metrology, Inspection, and Process Control XXXVII

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In this paper we have evaluated alignment and overlay for a Ruthenium Direct Metal Etch process. Depending on the integration strategy, line resistance and lithography requirements, a process with no remaining topography may be preferred from a lithography point of view, but due to the Ruthenium light absorption alignment and overlay through a thick Ruthenium layer will be challenging. In this paper we have studied the maximum thickness of Ruthenium for which the alignment sensor can still detect the alignment marks below and quantify the quality of diffraction-based overlay on an ASML YieldStar overlay metrology tool.

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Qualification of small alignment mark by on-product overlay performance

Cited by 2 publications

References 0 publications

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

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

Alignment and overlay through opaque metal layers

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