Lithography Patterning Device Scribe Line Sensing Mark Placement
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Solution Overview
Problem
Current lithographic apparatuses face limitations in design flexibility and throughput due to the placement and size of sensing marks, which can overlap with neighboring fields and require complex reticle masking, especially at higher numerical apertures like 0.55, leading to increased processing time and costs.
Innovation Solution
A patterning device with an imaging area and sensing marks positioned such that the marks fit within a scribe line on the substrate, allowing for reduced or eliminated reticle masking requirements, and the imaging area can be shifted closer to the edge of the patterning device while maintaining sub-nm thickness accuracy, using high-resolution reflectivity measurements for corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensing marks are placed adjacent to the imaging area, then alignment and measurement functions are enabled, but the marks overlap with neighboring fields and require complex reticle masking
Solution Approach 1:
The sensing mark is positioned to fit within the scribe line region, utilizing the vertical space between imaging fields rather than placing marks that would extend into neighboring field areas. This dimensional repositioning eliminates the need for complex Y-blade masking while preserving measurement functionality.
Solution Approach 2:
The sensing mark function is extracted from the traditional placement adjacent to imaging area boundaries and relocated to the scribe line region. This separation removes the conflict with neighboring fields and eliminates the requirement for reticle masking blades to cover the marks.
2Measurement precision
If sensing marks are placed adjacent to the imaging area, then alignment functions are provided, but throughput is reduced due to increased processing time
Solution Approach 1:
The sensing mark is extracted from the imaging area boundary region and relocated to the scribe line region. This removes the need for reticle masking operations that slow down throughput, while alignment and measurement functions are preserved through the strategic positioning within the scribe line.
Solution Approach 2:
The sensing mark utilizes the scribe line region (vertical dimension between fields) rather than placing marks that would require horizontal masking operations. This dimensional change eliminates the throughput bottleneck caused by Y-blade masking while maintaining alignment capability.
3Adaptability or versatility
If the imaging area is extended to utilize full patterning device area, then design flexibility is improved, but sensing marks cannot be properly positioned without overlapping fields
Solution Approach 1:
The sensing mark is positioned in the scribe line region (vertical dimension) rather than adjacent to imaging area edges (horizontal dimension). This allows the imaging area to extend to the full patterning device boundaries while sensing marks remain in the non-overlapping scribe line region, maintaining both design flexibility and measurement precision.
4Object-affected harmful factors
If reticle masking Y-blade is used to cover sensing marks, then mark overlap with neighboring fields is prevented, but the blade becomes a bottleneck for throughput
Solution Approach 1:
The sensing mark is extracted from the region requiring Y-blade coverage and relocated to the scribe line region. This eliminates the need for the Y-blade masking mechanism entirely, removing the throughput bottleneck while still preventing overlap with neighboring fields through proper positioning within the scribe line boundaries.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances throughput, reduces costs, and improves reflectivity uniformity, enabling full-field imaging at higher numerical apertures while maintaining precision and reducing the effective wafer area loss.
Implementation Method 1
A lithographic apparatus may, for example, project a pattern at a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate
Implementation Method 2
The sensing mark may be considered to be a (passive) reflective structure on the patterning device which is projected onto the substrate to be measurable by a sensor
Data Source
AI summary
A patterning device for a lithographic apparatus arranged to project a pattern from the patterning device onto a substrate, the patterning device comprising: an imaging area having opposing first sides extending parallel to a scanning direction of the lithographic apparatus and opposing second sides extending perpendicularly to the scanning direction, and at least one sensing mark located adjacent to at least one second side of the imaging area; wherein the at least one sensing mark is located a predetermined distance in the scanning direction away from the at least one second side of the imaging area and extends a width in the scanning direction such that the at least one sensing mark, when projected onto the substrate, fits within a scribe line on the substrate.