Adjustable Lithography Source Bandwidth Optimization
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Solution Overview
Problem
Current lithographic processes face challenges in achieving precise imaging of design layouts onto substrates with features smaller than the classical resolution limit, particularly due to the limitations of deep-ultraviolet illumination sources and the need for sophisticated fine-tuning of lithographic projection apparatuses and design layouts.
Innovation Solution
A method is introduced that computes a multi-variable cost function related to the bandwidth of a radiation source and adjusts design variables to optimize the lithographic process, allowing the bandwidth to change, thereby improving image quality and increasing the process window without altering geometrical characteristics of the patterning device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bandwidth of the illumination source is fixed at a narrow value to maintain imaging precision, then the resolution limit can be approached, but the process window and latitude of design variables are reduced
Solution Approach 1:
The patent applies dynamics by making the illumination source bandwidth adjustable rather than fixed. The system can dynamically change the bandwidth from narrow to wider values depending on the specific patterning requirements, allowing optimization of both imaging precision and process window for different design layouts and patterning devices.
Solution Approach 2:
The patent changes the physical parameter of the illumination source by allowing the bandwidth to vary. This parameter change enables the system to adapt to different critical dimension requirements and process conditions, resolving the contradiction between maintaining narrow bandwidth for precision and widening it for larger process window.
2Manufacturing precision
If sophisticated fine-tuning of lithographic projection apparatus is applied to achieve features smaller than classical resolution limit, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
Instead of increasing apparatus complexity through sophisticated fine-tuning mechanisms, the patent achieves improved manufacturing precision by changing the illumination source bandwidth parameter. This approach reaches sub-100nm features with a relatively simple system configuration, avoiding the need for complex additional tuning mechanisms.
3Adaptability or versatility
If the bandwidth of the illumination source is widened to increase process window, then adaptability improves, but imaging precision deteriorates
Solution Approach 1:
The system dynamically adjusts the illumination source bandwidth based on the specific requirements of the design layout and patterning device. For applications requiring high imaging precision, the bandwidth is narrowed; for applications requiring larger process window, the bandwidth is widened. This dynamic adaptation resolves the contradiction between the two opposing requirements.
Data Source
AI summary
A method to improve a lithographic process of imaging a portion of a design layout onto a substrate using a lithographic apparatus, the method including: computing a multi-variable cost function, the multi-variable cost function being a function a plurality of design variables that represent characteristics of the lithographic process; and reconfiguring one or more of the characteristics of the lithographic process by adjusting one or more of the design variables until a certain termination condition is satisfied; wherein a bandwidth of a radiation source of the lithographic apparatus is allowed to change during the reconfiguration.