Positive Resist Composition for 193nm Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional positive resist compositions face challenges in reducing line width roughness (LWR) and preventing footing when used on substrates with inorganic antireflection films, particularly in advanced lithography processes requiring high resolution and pattern miniaturization.
Innovation Solution
A positive resist composition incorporating a resin component with a structural unit derived from acrylate esters containing tertiary alkyl ester-type acid dissociable groups and an acid generator with a specific cation moiety, enhancing alkali solubility and acid generation for improved pattern formation and reduced LWR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PHS-based resins are used as base resin component, then high transparency to KrF excimer laser (248 nm) is achieved, but transparency is inadequate for light with wavelengths shorter than 248 nm such as 193 nm
Solution Approach 1:
The patent changes the chemical structure parameters of the base resin from PHS-based (aromatic rings) to acrylic resins with aliphatic polycyclic groups, which fundamentally alters the transparency characteristics at different wavelengths while maintaining the required lithography performance at 193 nm
Solution Approach 2:
The patent uses composite resin structures combining acrylic resins with specific aliphatic polycyclic groups and tertiary alkyl ester-type acid dissociable groups, creating a material that achieves both high transparency at 193 nm and appropriate solubility characteristics for pattern formation
2Manufacturing precision
If conventional positive resist composition is used, then basic pattern formation is achieved, but line width roughness (LWR) cannot be reduced and footing occurs on substrates with inorganic antireflection films
Solution Approach 1:
The patent introduces specific local chemical groups (aliphatic polycyclic groups and tertiary alkyl ester-type acid dissociable groups) into the resin structure at specific positions, which locally modify the material properties to reduce LWR and prevent footing while maintaining overall pattern formation capability
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating acrylic resins with specific functional groups that change the solubility and etching resistance characteristics, thereby improving reliability in terms of LWR reduction and footing suppression
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 solution effectively reduces LWR and suppresses footing on substrates with inorganic antireflection films, ensuring high-resolution pattern fidelity and excellent post-exposure bake margin.
Implementation Method 1
an acid generator component (B) which generates acid upon exposure
Implementation Method 2
the resist film is subjected to selective exposure of radial rays such as light or electron beam through a mask having a predetermined pattern
Data Source
AI summary
A positive resist composition including a resin component (A) which exhibits increased alkali solubility under action of acid and an acid-generator component (B) which generates acid upon exposure, the resin component (A) including a structural unit (a1) derived from an acrylate ester having a tertiary alkyl ester-type acid dissociable, dissolution inhibiting group containing an aliphatic monocyclic group and/or an aliphatic branched, tertiary alkyl ester-type acid dissociable, dissolution inhibiting group, and the acid-generator component (B) including an acid generator (B1) having a cation moiety represented by general formula (b′-1) shown below:wherein each of R1 and R2 independently represents a naphthyl group which may have a substituent; and R3 represents an alkyl group or an aryl group exclusive of a naphthyl group.