Radiation-Guided Finger Assembly Correction for Lithography Uniformity
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Solution Overview
Problem
Lithographic apparatuses face challenges in maintaining illumination uniformity, leading to non-uniform intensity profiles and image quality issues, which affect manufacturing efficiency and yield rates.
Innovation Solution
A system is introduced that includes a radiation source, detector, and processor to measure and adjust the shape of finger assemblies in the illumination system, using reference marks and a motion control system to correct for thermal drift caused by EUV or DUV radiation, thereby maintaining slit uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If finger assemblies are used to correct illumination non-uniformities, then illumination uniformity is improved, but thermal drift causes shape changes that degrade correction accuracy
Solution Approach 1:
The system uses a radiation detector to measure the actual shape of finger assemblies and feeds this information back to a controller, which then adjusts finger positions to compensate for thermal drift, maintaining correction accuracy despite temperature changes
Solution Approach 2:
The system dynamically changes the position parameters of finger assemblies based on measured thermal drift, adjusting their shapes and positions to maintain optimal illumination uniformity correction under varying thermal conditions
2Measurement precision
If additional sensors are added to measure finger assembly shape, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The radiation detector serves multiple functions: it measures the shape of finger assemblies for thermal drift detection, monitors illumination uniformity, and provides data for control adjustments, eliminating the need for separate dedicated sensors
Solution Approach 2:
The system uses the existing radiation detector and control infrastructure to perform shape measurements and corrections, making the measurement system self-sufficient without requiring additional external sensors or measurement devices
3Ease of operation
If finger assembly shape is allowed to change due to thermal drift, then ease of operation is improved, but illumination uniformity deteriorates
Solution Approach 1:
The system accepts and measures dynamic shape changes in finger assemblies due to thermal drift, then dynamically adjusts finger positions in real-time to maintain optimal illumination uniformity, transforming a static correction system into an adaptive one
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 system effectively reduces critical dimension (CD) drift and CDU impact, improving manufacturing throughput and reducing defects by minimizing uncorrected thermal drift without requiring additional sensors, thus enhancing overall performance.
Implementation Method 1
a radiation detector configured to: receive at least a portion of the transmitted radiation
Implementation Method 2
a processor configured to: determine a change in a shape of the finger assembly based on the received radiation
Implementation Method 3
generate a control signal configured to modify a position of the finger assembly based on the determined change in the shape of the finger assembly
Data Source
AI summary
Systems, apparatuses, and methods are provided for adjusting illumination slit uniformity in a lithographic apparatus. An example method can include irradiating, by a radiation source, a portion of a finger assembly with radiation. The example method can further include receiving, by a radiation detector, at least a portion of the radiation in response to the irradiating of the portion of the finger assembly. The example method can further include determining, by a processor, a change in a shape of the finger assembly based on the received radiation. The example method can further include generating, by the processor, a control signal configured to modify a position of the finger assembly based on the determined change in the shape of the finger assembly. Subsequently, the example method can include transmitting, by the processor, the control signal to a motion control system coupled to the finger assembly.