Immersion Lithography Quencher Neutralization
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Solution Overview
Problem
Immersion lithography in semiconductor manufacturing faces challenges with residual droplets of exposure fluids causing defects and damage, particularly due to quenchers diffusing into the resist and affecting pattern formation, which existing drying processes may not adequately address in a timely manner.
Innovation Solution
A method involving a quencher-neutralizing solution and a surface reduction mechanism, such as a solvent rinse, is applied to the semiconductor wafer after immersion lithography to neutralize and remove diffused quenchers, followed by a post-exposure bake and developing process to minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If immersion lithography is used to improve resolution, then manufacturing precision is improved, but harmful factors increase due to residual droplets affecting patterning
Solution Approach 1:
The patent applies a quencher-neutralizing solution to the wafer surface before the post-exposure bake step. This preliminary action neutralizes quenchers that have diffused into the resist during immersion lithography, preventing them from interfering with the subsequent bake and developing processes. By addressing the quencher issue in advance, the patent eliminates a major source of patterning defects while maintaining the resolution benefits of immersion lithography.
Solution Approach 2:
The patent introduces a quencher-neutralizing solution as an intermediary substance between the immersion fluid and the resist layer. This solution acts as a mediator that selectively neutralizes quenchers without damaging the resist or the desired pattern. The neutralizing solution contains basic compounds that react with acidic quenchers, converting them into non-interfering substances that can be easily removed, thereby eliminating droplet-related defects.
2Object-affected harmful factors
If a drying process is applied quickly to remove droplets, then harmful factors are reduced, but reliability decreases due to potential damage from rushed processing
Solution Approach 1:
The patent converts the harmful effect of quenchers diffusing into the resist into a beneficial neutralization reaction. By applying a basic quencher-neutralizing solution, the quenchers that caused damage are transformed into harmless or beneficial substances. This approach eliminates the need for aggressive drying processes, as the neutralized quenchers no longer cause patterning defects, thereby maintaining process reliability while removing harmful factors.
Solution Approach 2:
The quencher-neutralizing solution serves as a gentle intermediary that removes harmful quenchers without requiring forceful or rushed drying. The solution penetrates the resist surface and neutralizes quenchers through chemical reaction, a process that occurs naturally without mechanical stress. This intermediary approach eliminates droplet damage while preserving the integrity of the resist and pattern, avoiding the reliability issues associated with rapid drying.
3Manufacturing precision
If quenchers diffuse into the resist during exposure, then manufacturing precision deteriorates due to affected pattern formation, but removing quenchers requires additional processing steps
Solution Approach 1:
The patent merges the quencher removal function with the existing post-exposure bake process. The quencher-neutralizing solution is applied immediately before the bake, and the neutralization occurs during the same thermal processing step. This integration eliminates the need for a separate quencher removal step, maintaining manufacturing precision while avoiding additional processing complexity. The bake serves dual purposes: completing the photoresist chemistry and removing neutralized quenchers.
Solution Approach 2:
The post-exposure bake process is given multi-functionality: it simultaneously completes the photoresist crosslinking or dissolution chemistry and removes neutralized quenchers from the resist. By making the bake serve multiple functions, the patent eliminates the need for dedicated quencher removal equipment or steps, thereby improving pattern formation without increasing device complexity.
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 effectively reduces defects by neutralizing and removing quenchers, ensuring improved pattern formation and reducing the risk of damage from residual fluid, allowing for more precise and reliable semiconductor feature creation.
Implementation Method 1
quenchers that have diffused into the resist
Implementation Method 2
post-exposure bake
Data Source
AI summary
Provided is a method of performing a lithography process. The method includes: exposing, through an immersion lithography process, a photo-sensitive material on a substrate, the immersion lithography process using a fluid for the exposing; thereafter treating the photo-sensitive material with a solution to neutralize quenchers that have diffused into the photo-sensitive material through the liquid, wherein the solution contains a substance that diffuses into the photo-sensitive material at a first rate that is dependent on a second at which the quenchers diffuse into the photo-sensitive material; thereafter removing a portion of the photo-sensitive material; thereafter performing a post-exposure bake to the photo-sensitive material; and developing the photo-sensitive material.