Radiation-Sensitive Resin Composition for Low LWR Lithography
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Solution Overview
Problem
Current radiation-sensitive resin compositions for microfabrication by lithography face challenges in achieving high sensitivity, low Line Width Roughness (LWR) performance, and a broad process window, especially with the further miniaturization of resist patterns.
Innovation Solution
A radiation-sensitive resin composition is developed, comprising a polymer with a first structural unit capable of altering solubility in a developer solution upon acid action, a radiation-sensitive acid generating agent, and an acid diffusion control agent with a monovalent radiation-sensitive onium cation and a monovalent organic acid anion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional radiation-sensitive resin compositions are used, then manufacturing process is simple, but sensitivity and LWR performance are insufficient for further miniaturization
Solution Approach 1:
The patent uses a composite polymer system comprising a first polymer containing acid-labile groups and a second polymer containing basic groups. This composite structure enables simultaneous achievement of high sensitivity (through acid generation and solubility change) and low LWR (through basic group-mediated smoothing of resist profile), resolving the contradiction between manufacturing precision and composition complexity.
Solution Approach 2:
The patent introduces functional units with specific local properties: acid-labile groups at exposed regions for solubility enhancement, and basic groups distributed throughout for LWR control. This local differentiation of chemical properties within the polymer structure enables precise control over both sensitivity and line width roughness independently.
2Manufacturing precision
If polymer molecular weight is increased to improve LWR performance, then sensitivity decreases due to reduced acid diffusion
Solution Approach 1:
The patent changes the chemical parameter of the polymer by incorporating basic functional groups (such as amine groups) that can neutralize excess acid and control acid diffusion. This parameter change enables the use of higher molecular weight polymers for LWR control without sacrificing sensitivity, as the basic groups compensate for reduced acid mobility by providing localized acid neutralization.
3Reliability
If acid diffusion is increased to improve sensitivity, then LWR performance deteriorates due to broader acid distribution
Solution Approach 1:
The patent introduces basic functional groups as intermediary elements that mediate acid diffusion. These basic groups act as acid traps that selectively intercept diffusing acid, creating a buffering effect that limits acid spread while maintaining sufficient acid concentration at exposed regions for high sensitivity. This intermediary mechanism decouples the trade-off between sensitivity and LWR.
4Manufacturing precision
If process conditions are optimized for high precision, then process window narrows due to increased sensitivity to fluctuations
Solution Approach 1:
The patent incorporates basic functional groups that act as a cushion against process variations. These groups provide a buffering capacity that absorbs fluctuations in exposure dose and development conditions, maintaining stable resist pattern formation across a broader process window while preserving high precision at optimal conditions.
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 exhibits superior sensitivity and LWR performance, along with a broad process window, making it suitable for advanced semiconductor device manufacturing processes.
Implementation Method 1
generates an acid at light-exposed regions upon an irradiation with a radioactive ray, e.g., an electromagnetic wave such as a far ultraviolet ray such as an ArF excimer laser beam (wavelength of 193 nm), a KrF excimer laser beam (wavelength of 248 nm), etc. or an extreme ultraviolet ray (EUV) (wavelength of 13.5 nm), or a charged particle ray such as an electron beam
Implementation Method 2
A chemical reaction in which the acid serves as a catalyst causes a difference between the light-exposed regions and light-unexposed regions in rates of dissolution in a developer solution
Data Source
AI summary
A radiation-sensitive resin composition includes a polymer, solubility of which in a developer solution is capable of being altered by an action of an acid, and which has a first structural unit represented by the following formula (1); a radiation-sensitive acid generating agent; and an acid diffusion control agent having a monovalent radiation-sensitive onium cation and a monovalent organic acid anion.