Positive Resist Composition Acid Diffusion Control
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Solution Overview
Problem
Current positive resist compositions face challenges in achieving high resolution, minimal edge roughness, and improved etch resistance, particularly in the context of microelectronic device manufacturing where pattern feature sizes are reduced, leading to issues with acid diffusion and sensitivity.
Innovation Solution
A chemically amplified positive resist composition is developed, utilizing a polymer with recurring units containing ester groups from carbinol derivatives like indane, tetrahydronaphthalene, acenaphthylene, or fluorene, which suppress acid diffusion and enhance dissolution contrast and etch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the accelerating voltage is increased to reduce pattern feature size, then resolution is improved, but sensitivity of resist film is lowered
Solution Approach 1:
The patent changes the chemical composition parameters of the resist film by incorporating specific polymers with acid-labile groups ( formulas (1)-(3) ) and controlling the content of specific recurring units (formula (4)) to optimize the balance between sensitivity and resolution at high accelerating voltages
Solution Approach 2:
The patent uses a composite resist composition containing multiple polymer components including the specific polymer of formula (4), polymers with recurring units of formulas (5) and (6), and optional third and fourth polymers, creating a multi-component system that achieves both high sensitivity and high resolution
2Measurement precision
If the resist film is thinned to reduce pattern feature size and prevent collapse, then resolution is improved, but dry etch resistance is reduced
Solution Approach 1:
The patent modifies the chemical structure parameters of the resist film by incorporating polymers with specific acid-labile groups and controlling the composition ratios to achieve both thin film capability and sufficient etch resistance
Solution Approach 2:
The patent creates different functional zones within the resist film by incorporating polymers with different properties: some providing etch resistance (formulas (5) and (6)) and others providing acid diffusion control (formula (4)), allowing the film to exhibit both thin-film resolution and etch resistance locally
3Reliability
If chemically amplified resist compositions are used to increase sensitivity, then sensitivity is improved, but acid diffusion increases leading to reduced resolution
Solution Approach 1:
The patent introduces specific polymer molecules with acid-labile groups as intermediaries that capture and localize acid diffusion, preventing excessive acid spread while maintaining the sensitivity enhancement from chemical amplification
Solution Approach 2:
The patent optimizes the concentration and structural parameters of the acid-labile groups in the polymer to control acid diffusion distance, achieving a balance where enough acid diffusion occurs for sensitivity but not so much that resolution is compromised
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 resolution, minimal edge roughness, and improved etch resistance, making it suitable for fabricating VLSIs and photomasks with fine patterns, while maintaining sensitivity and process adaptability.
Implementation Method 1
a polymer having carboxyl groups whose hydrogen is substituted by an acid labile group having a specific structure which has a strong tendency to suppress an acid diffusion rate
Implementation Method 2
chemically amplified positive resist composition
Data Source
AI summary
A positive resist composition comprising a polymer having carboxyl groups substituted with an acid labile group having formula (1), (2) or (3) 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, R2, R5, R6, R8, and R9 are alkyl, aryl, or alkenyl, R3, R4, R7, R10, and R11 are hydrogen, alkyl, alkoxy, acyloxy, halogen, cyano, nitro, hydroxyl or trifluoromethyl, M is methylene or ethylene, R is a single bond or linking group.