Positive Resist Composition for High-Resolution Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current positive resist compositions face challenges in achieving high resolution, minimal edge roughness, and improved etch resistance, particularly with the increasing complexity of microelectronic device manufacturing at smaller node sizes, where sensitivity and acid diffusion control are critical.
Innovation Solution
A chemically amplified positive resist composition is developed using a polymer with recurring units containing fluorinated indane or tetrahydronaphthalene-containing tertiary ester acid labile groups, which enhances deprotection reaction control, suppresses acid diffusion, and improves etch resistance, thereby achieving high resolution and minimal edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the accelerating voltage is increased to improve resolution and dimensional control, then the contrast of electron image writing energy is improved, but the sensitivity of resist film is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the resist film by incorporating specific polymers with carboxyl groups and acid-labile groups that have optimized proton mobility and deprotection characteristics. This allows the resist to maintain high sensitivity even when exposed to high accelerating voltages (50-100 keV) that improve resolution, thereby resolving the contradiction between sensitivity and dimensional control.
Solution Approach 2:
The patent uses composite polymer structures combining carboxyl-containing polymers with acid-labile groups in specific ratios. This composite approach creates a resist system where the carboxyl groups provide sensitivity through efficient proton generation and transfer, while the acid-labile groups enable precise deprotection patterns for high-resolution imaging, thus achieving both high sensitivity and excellent dimensional control.
2Manufacturing precision
If the resist film thickness is reduced to improve resolution and prevent pattern collapse, then the aspect ratio is improved, but the dry etch resistance is reduced
Solution Approach 1:
The patent modifies the chemical parameters of the resist film by incorporating polymers with specific acid-labile groups that provide enhanced etch resistance through crosslinking reactions. These groups undergo acid-catalyzed deprotection to form crosslinked structures that maintain film integrity during dry etching, allowing thin film profiles (reducing aspect ratio) to achieve both high resolution and sufficient etch resistance.
Solution Approach 2:
The patent applies preliminary chemical modification to the resist film through acid-labile groups that crosslink during or before the etching process. This preliminary crosslinking action strengthens the thin resist film structure, providing the necessary dry etch resistance while maintaining the thin profile required for high-resolution patterning and collapse prevention.
3Productivity
If chemically amplified resist compositions are used to improve sensitivity, then the throughput is improved, but the acid diffusion control becomes more difficult
Solution Approach 1:
The patent optimizes the chemical parameters of the acid-labile groups and their spatial distribution within the polymer structure. By controlling the density and positioning of these groups, the patent limits acid diffusion distance and range while maintaining the chemically amplified sensitivity mechanism. This allows high throughput via chemical amplification while preserving sharp pattern edges through controlled acid diffusion.
Solution Approach 2:
The patent creates local variations in the resist composition by strategically placing acid-labile groups in specific micro-environments within the polymer matrix. This local quality control ensures that acid diffusion is confined to localized regions around exposed areas, preventing excessive spread while maintaining the sensitivity benefits of chemical amplification for high-throughput manufacturing.
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 resist composition exhibits high alkaline dissolution contrast, improved etch resistance, and minimal edge roughness, making it suitable for fine pattern formation in VLSIs and photomasks, while maintaining process adaptability and exposure latitude.
Implementation Method 1
a polymer having carboxyl groups whose hydrogen is substituted by an acid labile group... enhances deprotection reaction control
Implementation Method 2
suppresses acid diffusion... making it suitable for fine pattern formation
Implementation Method 3
For EB writing which is not affected by absorption... chemically amplified resist compositions are contemplated
Data Source
AI summary
A positive resist composition comprising a polymer having carboxyl groups substituted with an acid labile group having formula (1) exhibits a high contrast of alkaline dissolution rate before and after exposure, a high resolution, a reduced acid diffusion rate, and forms a pattern with good profile, minimal edge roughness, and etch resistance. In formula (1), R1 is methylene or ethylene, R2 is alkyl, aryl, or alkenyl, which may contain oxygen or sulfur, R3 is fluorine or trifluoromethyl, and m is an integer of 1 to 4.