Finger Assembly Drift Correction for Lithography Slit 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, yield rates, and increase costs.
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 reduce correction precision
Solution Approach 1:
The system measures shape changes of finger assemblies by detecting changes in their physical parameters (position, orientation) using a radiation detector. The processor compares measured parameters against reference parameters to quantify shape changes caused by thermal drift, enabling dynamic compensation
Solution Approach 2:
The system establishes a feedback loop where the radiation detector continuously monitors finger assembly shapes, the processor analyzes the measurements to determine shape changes, and the motion control system adjusts finger positions based on this feedback to maintain correction precision despite thermal drift
2Measurement precision
If additional sensors are added to measure finger assembly shape changes, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The radiation detector serves multiple functions: it detects the shape of finger assemblies for uniformity correction, measures shape changes caused by thermal drift, and provides data for both real-time correction and diagnostic purposes. This multi-functionality eliminates the need for separate dedicated sensors
Solution Approach 2:
The existing radiation detector in the illumination system is utilized to perform the additional measurement function of monitoring finger assembly shapes. The system uses its own existing detection capability to self-monitor and self-correct, avoiding the need for external or additional sensing components
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 machine performance.
Implementation Method 1
a radiation detector configured to receive at least a portion of the transmitted radiation
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.