Lithography Level Sensor Concurrent Scanning for Topography Bias
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Solution Overview
Problem
Existing topography measurement methods in lithography operations lack adequate scanning speed and accuracy, particularly for advanced technology nodes, which can impact exposure performance.
Innovation Solution
An enhanced level sensor device with revised scanning approaches and arranged scanning angles and routes is introduced to concurrently scan surfaces of different fields of a workpiece, reducing topography measurement bias and improving exposure performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional topography measurement methods are used, then measurement capability is provided, but scanning speed and accuracy are insufficient for advanced technology nodes
Solution Approach 1:
The workpiece surface is divided into multiple fields that are scanned concurrently by multiple level sensors positioned at different locations. Each level sensor scans a specific field independently, allowing parallel measurement across the entire workpiece surface, thereby increasing scanning speed while maintaining measurement accuracy through the distributed sensor array
Solution Approach 2:
The patent transitions from sequential one-dimensional scanning to two-dimensional concurrent scanning by arranging level sensors across multiple fields. This spatial dimensionality change enables simultaneous measurement of multiple areas, resolving the contradiction between scanning speed and measurement precision by utilizing parallel processing in the spatial domain
2Reliability
If conventional scanning approaches are used, then topography data is collected, but measurement bias occurs affecting exposure performance
Solution Approach 1:
Different level sensors are positioned to scan different fields with optimized local scanning parameters. Each sensor measures the topography of its specific field with tailored scanning angles and routes, reducing local measurement biases that would affect overall exposure performance. This localized optimization ensures high measurement precision and reliability across the entire workpiece surface
3Productivity
If scanning speed is increased to meet production demands, then productivity improves, but measurement accuracy deteriorates
Solution Approach 1:
Multiple level sensors are merged into a coordinated measurement system that simultaneously scans multiple fields. The combined measurement data from all sensors provides comprehensive topography information at high speed, maintaining measurement precision through the collective capability of the sensor array while achieving high productivity through parallel operation
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
The solution enhances scanning speed and accuracy, leading to improved exposure performance by effectively reducing measurement bias and optimizing the scanning process for advanced technology nodes.
Implementation Method 1
an array of level sensors arranged on a support structure. Each of the level sensors includes an emitter configured to emit a sensing light to a surface of the material layer, and a detector configured to receive the sensing light reflected from the surface of the material layer
Data Source
AI summary
A method includes providing a workpiece to a semiconductor apparatus, the workpiece including a material layer, wherein the material layer includes a plurality of first strips. Each of the first strips includes a first plurality and a second plurality of exposure fields, wherein the first plurality of exposure fields and the second plurality of exposure fields are configured with different exposure parameters. The method further includes scanning each of the first strips along a first scan direction from a first side of the workpiece to a second side of the workpiece to generate first topography measurement data, scanning each of the first strips along a second scan direction from the second side to the first side to generate second topography measurement data, and generating data of depth of focus (DOF) for each of the first plurality of exposure fields and each of the second plurality of exposure fields.