Onium Salt Resist Composition for EUV Pattern Collapse Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing chemically amplified resist compositions face challenges in suppressing acid diffusion, leading to degraded lithography properties such as contrast, exposure latitude, line width roughness, critical dimension uniformity, and depth of focus, while also experiencing pattern collapse during development.
Innovation Solution
Incorporation of an onium salt with a sulfonium cation containing a nitro group and an aromatic carboxylic acid anion with iodine atoms into a chemically amplified resist composition, which acts as a quencher, enhances sensitivity, resolution, and prevents pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed by reducing temperature and/or time of post exposure bake, then resolution is improved, but sensitivity and contrast are drastically reduced
Solution Approach 1:
The invention changes the chemical parameters of the acid generator by using a sulfonium salt with specific structural features (formula 1) that generates a bulky acid with controlled diffusion characteristics, allowing resolution improvement without sacrificing sensitivity and contrast
Solution Approach 2:
The invention creates a composite resist system combining a specific polymer (formula 2) with a specially designed sulfonium salt (formula 1) and acid labile groups, where the synergistic interaction between components achieves both high resolution and maintained sensitivity/contrast
2Manufacturing precision
If acid diffusion distance is reduced to improve resolution, then manufacturing precision is improved, but sensitivity and contrast are reduced
Solution Approach 1:
The invention applies local quality control by designing the acid generator to produce a bulky acid that diffuses locally with controlled distance, while the polymer matrix provides localized environments that maintain sensitivity and contrast in specific regions of the resist
3Manufacturing precision
If conventional sulfonium or iodonium salts are used, then deprotection reaction occurs, but α-non-fluorinated sulfonic acid or carboxylic acid functions as quencher causing acid diffusion
Solution Approach 1:
The invention converts the harmful acid diffusion effect into a beneficial controlled process by using a sulfonium salt that generates a bulky acid with limited diffusion, where the acid still performs necessary deprotection reactions but its diffusion is controlled to improve resolution rather than degrade it
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 onium salt composition achieves high sensitivity, improved lithography properties including exposure latitude, line width roughness, critical dimension uniformity, and depth of focus, while preventing pattern collapse during the formation of small-size patterns.
Implementation Method 1
an acid generator capable of generating a bulky acid
Implementation Method 2
the sulfonium or iodonium salt capable of generating α-non-fluorinated sulfonic acid undergoes ion exchange with the α-fluorinated sulfonic acid
Data Source
AI summary
The onium salt consists of a cation having the formula (1A) and an anion having the formula (1B). The chemically amplified resist composition comprises the onium salt. The resist composition exhibits a high sensitivity, high resolution, improved lithography properties including EL, LWR, CDU and DOF, and collapse resistance, when processed by lithography using high-energy radiation such as deep UV, EB, or EUV.