Multi-Beam Pattern Generator Dose Control for Photoresist Thickness
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Solution Overview
Problem
Microlithography techniques face challenges in achieving uniform photoresist thickness on large, non-circular substrates, leading to variations in feature sizes, which negatively impact the performance of electronic devices.
Innovation Solution
A multi-beam pattern generator employing processors to adjust the delivery dose of writing beams based on photoresist thickness, using actuator dwell times, pulse duration, pulse frequency, and pulse intensity to ensure precise control over pattern features on substrates with variable photoresist thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If spin coating is used to apply photoresist on large rectangular substrates, then substrate size can be increased, but photoresist thickness uniformity deteriorates
Solution Approach 1:
The patent applies local quality by varying the writing beam dose according to the local photoresist thickness at different substrate locations. The system measures thickness variations across the substrate and adjusts the exposure dose locally to compensate for non-uniform thickness, ensuring uniform pattern dimensions despite thickness variations.
Solution Approach 2:
The patent changes the writing beam dose parameter based on measured photoresist thickness. By dynamically adjusting the exposure dose parameter in response to thickness variations, the system maintains consistent pattern dimensions across the entire substrate area.
2Area of stationary object
If photoresist thickness is not uniform across the substrate, then larger substrate area can be processed, but feature size variation increases
Solution Approach 1:
The patent implements feedback by measuring the actual photoresist thickness at each location on the substrate and using this information to adjust the writing beam dose. This closed-loop control ensures that feature sizes remain uniform across the entire substrate area despite variations in photoresist thickness.
Solution Approach 2:
The system changes the exposure dose parameter based on measured thickness variations, allowing uniform feature sizes to be achieved across large substrate areas where photoresist thickness is non-uniform.
3Productivity
If conventional microlithography is used on large substrates, then processing capacity increases, but pattern uniformity deteriorates
Solution Approach 1:
The patent segments the substrate into multiple measurement and exposure zones, allowing independent dose adjustment for each region. This segmentation enables uniform patterning across the entire large substrate while maintaining high processing capacity through efficient zone-based processing.
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 approach provides additional dimensional control and more predictable performance characteristics for electronic devices by compensating for photoresist thickness variations, resulting in more uniform pattern features.
Implementation Method 1
a radiation-sensitive photoresist is applied to form a layer on a substrate surface
Data Source
AI summary
Multi-beam pattern generators employing processors to vary delivered dose of writing beams according to photoresist thicknesses, and associated methods are disclosed. A pattern generator may write a pattern upon a substrate having a photoresist which is sensitive to the writing beams. The pattern may be written in respective writing cycles when the writing beams write at least a portion of the pattern at writing pixel locations. A beam actuator of the pattern generator may independently direct the writing beams to the writing pixels to deliver respective pixel doses during each writing cycle. Pixel doses delivered may be adjusted according to a thickness of the photoresist at various writing pixel locations according to one or more approaches, using one or more of: actuator dwell times, emitted pulse duration, emitted pulse frequency, and emitted pulse intensity. In this manner, additional dimensional control is provided for substrates having variable photoresist thicknesses.