Optical overlay metrology trends in advanced nodes

Katz, Shlomit; Grauer, Yoav; Megged, Efi

doi:10.1117/12.2605863

Cited by 4 publications

(4 citation statements)

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“…Layer-to-layer misalignment measurements, commonly called overlay (OVL) metrology, is one of the most critical metrology steps in the modern semiconductor manufacturing process as part of on-product OVL (OPO) reduction [1]- [2]. There are multiple requirements implied in this step, but the most important requirement for OVL metrology is the accuracy of OVL reported.…”

Section: Introductionmentioning

confidence: 99%

Small pitch overlay imaging metrology targets for tight OPO control

Roy,

Housley,

Manampurathu

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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Sub-2nm On Product Overlay (OPO), scribe line width reduction, and high-order scanner correctibles are driving innovative overlay (OVL) targets. One promising new imaging-based overlay (IBO) OVL target to address such challenging trends in multiple semiconductor segments is a small pitch AIM ® (sAIM™). sAIM is in essence an IBO target with grating (previous layer) beside grating (current layer) which could be placed in a few layouts: square, rectangular, and Mosaic. In this work, we will present the sAIM operational concept and performance including Total Measurement Uncertainty (TMU), residuals, and accuracy (ADI on-target offset vs. ACI on-device or target), which is often referred to as Non-Zero Offset (NZO).

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Section: Introductionmentioning

confidence: 99%

Small pitch overlay imaging metrology targets for tight OPO control

Roy,

Housley,

Manampurathu

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

View full text Add to dashboard Cite

show abstract

“…As the dimensions of the integrated circuit elements, the OVL targets are printed simultaneously with device-like patterns to perform the optical measurements. Onproduct OVL (OPO) is reduced from node to node to support device scaling [1]- [2]. AIM targets with periodic patterns, in either vertical or parallel patterns, can be resolvable within visible microscopy.…”

Section: Introductionmentioning

confidence: 99%

NZO reduction via small pitch imaging-based overlay targets

Cheng,

Hong,

Huang

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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On-product overlay (OPO) control in the DRAM process has become a critical component from node to node to produce high device yield. To meet OPO node goals, Non-Zero Offset (NZO) and its stability across lots must be monitored and controlled. NZO is the bias between overlay (OVL) on-target measurement at After Development Inspection (ADI) vs. ondevice measurement at After Etching Inspection (AEI). In this paper, we will present Imaging-Based Overlay (IBO) metrology data at ADI of two different marks, segmented AIM ® with design rule patterns and robust AIM (rAIM ® ) with Moiré effect with a small pitch. NZO analysis will be presented for each target type including basic performance.

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“…Accurate overlay (OVL) measurement is one of the key elements of semiconductor chip production. Since on-product overlay (OPO) tolerances become smaller and smaller from node to node, the sampling (the number of marks and their spread) becomes denser and drives tighter accuracy stability and residual reduction [1]- [2]. This trend requires more and more area for the auxiliary structure (the OVL marks); thus, target size reduction, improved OVL metrology tools, and robust OVL targets become a necessity.…”

Section: Introductionmentioning

confidence: 99%

Small imaging overlay metrology targets for advance nodes

Feler

Shaphirov

Ghinovker

et al. 2023

Metrology, Inspection, and Process Control XXXVII

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Scribe line width reduction and high-order scanner correctibles are driving overlay (OVL) target size reduction. Shrinking imaging-based overlay (IBO) target size for standard target types, such as AIM® or BiB, is not possible without a performance impact. In this paper, new target layouts and supporting OVL tool setup methods will be explored to enable small OVL targets to meet performance, accuracy, and robustness requirements. Two approaches have been explored: (1) measuring smaller grating pitches utilizing oblique illumination, and (2) measuring targets not obeying 180° rotational symmetry requirement (half-targets). Each of these approaches allows shrinking conventional imaging OVL target area by a factor of two. Evaluation results are reviewed in this paper and further target size reduction is presented.

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Optical overlay metrology trends in advanced nodes

Cited by 4 publications

References 0 publications

Small pitch overlay imaging metrology targets for tight OPO control

Small pitch overlay imaging metrology targets for tight OPO control

NZO reduction via small pitch imaging-based overlay targets

Small imaging overlay metrology targets for advance nodes

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