Multi-tone Lithography Exposure via Iterative Dosage Control
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Solution Overview
Problem
Conventional lithography systems require multiple passes to expose full tone and grey tone patterns in photoresists, leading to decreased throughput and overlay issues during the manufacturing of semiconductor and display devices.
Innovation Solution
A system and method that iteratively exposes a photoresist using a lithography system with image projection systems and a controller, moving the stage between exposures to achieve different dosage amounts in a single pass, allowing for the formation of full tone features in a photoresist by generating multiple processing address grids and frame layers associated with varying dosage amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple passes are used to expose full tone and grey tone patterns, then the lithography system can achieve the required dosage amounts, but the throughput decreases and overlay problems occur
Solution Approach 1:
The patent segments the photoresist exposure area into multiple distinct regions (full tone region, grey tone region, and clear region) that can be exposed simultaneously in a single pass. Each region receives the appropriate dosage amount through dedicated beam paths and control mechanisms, eliminating the need for multiple sequential passes while maintaining precise dosage control for each tone type.
2Manufacturing precision
If multiple passes are used to expose full tone and grey tone patterns, then the required dosage amounts can be achieved, but overlay problems occur due to multiple substrate loadings and alignments
Solution Approach 1:
The patent merges the exposure of full tone patterns and grey tone patterns into a single simultaneous operation. By combining multiple exposure functions into one unified process step, the system eliminates the need for separate substrate loadings and alignments, thereby preventing overlay errors while maintaining precise dosage delivery to each pattern type.
3Productivity
If a single pass is used to expose multiple tones, then the throughput is improved, but the system complexity increases
Solution Approach 1:
The patent implements a multi-functional lithography system where a single exposure apparatus can simultaneously perform multiple exposure functions (full tone exposure, grey tone exposure, and clear region exposure) through programmable beam control and configurable optical paths. This universal capability allows the system to handle different tone requirements without adding separate dedicated equipment, thereby managing complexity while enabling single-pass multi-tone exposure.
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
Enables the creation of complex three-dimensional structures in a photoresist in a single pass, reducing the need for multiple substrate loadings and alignments, thus improving throughput and avoiding overlay errors.
Implementation Method 1
Each of the exposures includes using one or more write beams projected from the image projection systems. Each of the exposures is at a respective one of different dosage amounts.
Data Source
AI summary
Examples described herein provide a system, a software application, and a method of a lithography process to write multiple tones in a single pass. A system includes a stage and a lithography system. The lithography system includes image projection systems, a controller, and memory. The controller is coupled to the memory, which stores instruction code. Execution of the instruction code by the controller causes the controller to control the stage and the image projection systems to iteratively expose a photoresist supported by the stage and to move the stage relative to the image projection systems a step distance between sequential pairs of the exposures. Each exposure includes using write beam(s) projected from the image projection systems. Each exposure is at a respective one of different dosage amounts. An accumulation of the different dosage amounts is a full tone dosage amount for the photoresist.