Iodized Lactone Resist Polymer for Resolution and Sensitivity Tradeoff
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Solution Overview
Problem
Current chemically amplified positive resist compositions face challenges in achieving high sensitivity, resolution, and minimal edge roughness for microelectronic device manufacturing, particularly at the 45-nm node and beyond, due to acid diffusion issues and tradeoffs between sensitivity and edge roughness.
Innovation Solution
A positive resist composition incorporating a polymer with recurring units derived from (meth)acrylate having an iodized lactone ring, combined with carboxyl or phenolic hydroxyl groups substituted by acid labile groups, enhances sensitivity, resolution, and acid diffusion control, forming a polymer with improved properties for micropatterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed to achieve resolution improvement, then manufacturing precision is improved, but sensitivity is reduced
Solution Approach 1:
The patent changes the chemical parameters of the acid generator by using onium salts with polymerizable unsaturated bonds (sulfonium or iodonium salts) that generate bulky acids with smaller diffusion coefficients, thereby suppressing acid diffusion while maintaining sensitivity through the unique chemical properties of these salts
Solution Approach 2:
The patent creates a composite material system by incorporating onium salts with polymerizable unsaturated bonds into the polymer structure, combining the acid-generating capability with the diffusion-suppressing effect of the polymer backbone, achieving both high resolution and maintained sensitivity
2Quantity of substance
If exposure dose is increased to reduce shot noise and improve sensitivity, then sensitivity is improved, but edge roughness increases
Solution Approach 1:
The patent changes the chemical parameters by introducing onium salts with polymerizable unsaturated bonds that generate bulky acids, which have smaller diffusion coefficients and reduce edge roughness while maintaining the sensitivity enhancement from acid diffusion
3Manufacturing precision
If quencher amount is increased to reduce roughness, then edge roughness is reduced, but sensitivity is reduced
Solution Approach 1:
The patent changes the fundamental parameter of acid generation by using onium salts with polymerizable unsaturated bonds that generate bulky acids with smaller diffusion coefficients, reducing edge roughness without requiring additional quencher that would reduce sensitivity
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 sensitivity, resolution, and minimal edge roughness, suitable for micropatterning in VLSI and photomask fabrication, with enhanced acid diffusion suppression and pattern profile quality.
Implementation Method 1
a pattern forming method comprising: coating a positive resist composition comprising a polymer having recurring units (a) having the formula (a), and recurring units (b1) having a carboxyl group whose hydrogen is substituted by an acid labile group and/or recurring units (b2) having a phenolic hydroxyl group whose hydrogen is substituted by an acid labile group, and an acid generator, on a substrate to form a resist film
Implementation Method 2
exposing the resist film to radiation to form a latent image
Implementation Method 3
control of acid diffusion is also important as reported in Non-Patent Document 1. Since chemically amplified resist compositions are designed such that sensitivity and contrast are enhanced by acid diffusion, an attempt to minimize acid diffusion by reducing the temperature and/or time of post-exposure bake (PEB) fails
Implementation Method 4
recurring units (b1) having a carboxyl group whose hydrogen is substituted by an acid labile group and/or recurring units (b2) having a phenolic hydroxyl group whose hydrogen is substituted by an acid labile group
Data Source
AI summary
A positive resist composition based on a polymer comprising recurring units (a) of (meth)acrylate having an iodized lactone ring, and recurring units (b1) having a carboxyl group substituted with an acid labile group and/or recurring units (b2) having a phenolic hydroxyl group substituted with an acid labile group has a high sensitivity and resolution, and forms a pattern of good profile and minimal edge roughness after exposure.