Resist Patterning via Segmented Exposure for Sensitivity and Roughness
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Solution Overview
Problem
Conventional resist patterning methods face a trade-off between sensitivity, resolution, and line width roughness (LWR), with increasing sensitivity leading to decreased resolution and increased LWR, and no effective solution for reducing photon shot noise-induced roughness.
Innovation Solution
A resist patterning method involving a resist layer with a base resin, sensitizer precursor, strong acid generator, and base, where patterned and flood exposures are used to produce sensitizer and acid, allowing for improved sensitivity and reduced roughness through controlled acid and radical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sensitivity of resist materials is increased to reduce exposure time, then the throughput is improved, but the resolution decreases and line width roughness increases
Solution Approach 1:
The patent segments the photochemical reaction process into two distinct stages: patterned exposure that forms the initial latent image, and flood exposure that uniformly generates acid throughout the resist layer. This segmentation allows each stage to be optimized independently - patterned exposure maintains resolution while flood exposure enhances sensitivity and reduces roughness by providing uniform acid distribution
Solution Approach 2:
The patent performs preliminary patterned exposure to form a latent image distribution of sensitizer before conducting flood exposure. This preliminary action creates a spatial template that guides subsequent uniform acid generation, ensuring that high sensitivity and low roughness are achieved while maintaining the resolved pattern structure
2Productivity
If the sensitivity of resist materials is increased to reduce exposure time, then the throughput is improved, but the line width roughness increases
Solution Approach 1:
The patent separates the exposure process into patterned and flood exposure stages, where flood exposure uniformly generates acid throughout the resist layer. This uniform acid distribution prevents localized variations in reaction intensity, thereby reducing line width roughness while enabling higher sensitivity and throughput
Solution Approach 2:
The patent changes the exposure parameters by introducing a second flood exposure stage with different illumination conditions compared to the initial patterned exposure. This parameter change enables uniform acid generation that reduces roughness while maintaining high sensitivity for improved throughput
3Productivity
If conventional single exposure methods are used, then the process is simple, but the sensitivity cannot be sufficiently increased without compromising resolution and roughness
Solution Approach 1:
The patent divides the exposure process into two sequential steps: patterned exposure for latent image formation and flood exposure for uniform acid generation. This segmentation enables high sensitivity achievement while maintaining resolution and roughness control, overcoming the limitations of conventional single exposure methods
Solution Approach 2:
The patent implements continuous useful action by performing flood exposure immediately after patterned exposure while the latent image is still present. This continuous process ensures that the sensitizer distribution created in the first step is fully utilized in the second step, maximizing sensitivity without requiring additional complex 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
The method enhances resist sensitivity while maintaining resolution and reducing line width roughness, improving throughput and reducing photon shot noise-induced roughness, thus addressing the trade-off limitations of conventional techniques.
Implementation Method 1
a step of producing a strong acid from the strong acid generator; a step of producing the sensitizer through a reaction between the strong acid and the sensitizer precursor
Implementation Method 2
a flood exposure step of performing flood exposure on the resist layer in which the sensitizer has been produced to produce an acid from the strong acid generator after the patterned exposure step
Implementation Method 3
producing the sensitizer through a reaction between the weak acid and the sensitizer precursor
Data Source
AI summary
A resist patterning method includes a resist layer forming step, a patterned exposure step, a flood exposure step, and a developing step. In the resist layer forming step, a resist layer is formed on a substrate. In the patterned exposure step, a sensitizer is produced from a sensitizer precursor in the resist layer. In the flood exposure step, flood exposure is performed on the resist layer in which the sensitizer has been produced to produce an acid from a strong acid generator. In the developing step, the resist layer is developed. The patterned exposure step includes: producing a strong acid from the strong acid generator; producing the sensitizer through a reaction between the strong acid and the sensitizer precursor; producing a weak acid through a reaction between the strong acid and a base; and producing the sensitizer through a reaction between the weak acid and the sensitizer precursor.