Positive Resist Composition with Nitrobenzene-Substituted Polymer
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Solution Overview
Problem
Existing positive resist compositions face challenges in achieving high sensitivity, resolution, and dissolution contrast while minimizing acid diffusion, leading to issues with edge roughness and size variation in microelectronic device patterning.
Innovation Solution
Incorporating a base polymer with repeat units having a carboxy group substituted by a nitrobenzene ring-containing tertiary hydrocarbyl group, along with other acid labile groups, to enhance dissolution contrast and minimize acid diffusion, resulting in a positive resist composition with improved resolution and reduced edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed to improve resolution, then edge roughness is reduced, but sensitivity and dissolution contrast decrease
Solution Approach 1:
The patent changes the chemical parameters of the acid generator by using a polymer-bound acid generator with specific molecular weight and structure. This modifies the acid diffusion characteristics while maintaining sufficient sensitivity, resolving the contradiction between resolution and sensitivity
Solution Approach 2:
The patent uses a composite resist composition containing the polymer-bound acid generator combined with specific base polymers and additives. This composite approach enables simultaneous achievement of high sensitivity, resolution, and edge roughness control
2Manufacturing precision
If acid diffusion is suppressed to improve resolution, then edge roughness is reduced, but dissolution contrast decreases
Solution Approach 1:
The patent modifies the chemical parameters of the resist system by introducing polymer-bound acid generators with controlled molecular weights and structures, which alter the acid diffusion profile while preserving dissolution contrast through optimized chemical composition
Solution Approach 2:
The polymer-bound acid generator acts as an intermediary that mediates between the need for acid diffusion (for sensitivity) and the need to suppress acid diffusion (for resolution). The polymer structure controls the release and diffusion of acid, balancing both requirements
3Manufacturing precision
If post-exposure bake temperature and time are reduced to minimize acid diffusion, then resolution is improved, but sensitivity and contrast are drastically reduced
Solution Approach 1:
The patent changes the PEB parameters (temperature and time) in combination with the polymer-bound acid generator to achieve a new operating point that maintains both high sensitivity and high resolution, rather than simply reducing PEB conditions
Solution Approach 2:
The patent replaces the conventional approach of controlling resolution through physical parameters (PEB temperature and time) with a chemical approach using polymer-bound acid generators that inherently control acid diffusion through their molecular structure
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 composition achieves high sensitivity, resolution, and reduced edge roughness, forming patterns with improved critical dimension uniformity and line width roughness, suitable for micropatterning in VLSIs and photomasks.
Implementation Method 1
an acid generator capable of generating a bulky acid
Implementation Method 2
image blurs due to acid diffusion become a problem
Data Source
AI summary
A positive resist composition is provided comprising a base polymer comprising repeat units having a carboxy group whose hydrogen is substituted by a nitrobenzene ring-containing tertiary hydrocarbyl group. The resist composition has a high sensitivity and resolution and forms a pattern of good profile with reduced edge roughness and size variation after exposure.