Iodized Phenol Quencher for Lithography Resist Resolution
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Solution Overview
Problem
As feature sizes in microelectronic devices decrease, image blurs due to acid diffusion become a significant issue, affecting sensitivity, resolution, and edge roughness in resist compositions used in lithography processes.
Innovation Solution
Incorporating a sulfonium salt of an iodized phenol compound as a quencher in resist compositions to suppress acid diffusion, thereby improving sensitivity, reducing line width roughness (LWR), and enhancing critical dimension uniformity (CDU).
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 suppressed diffusion characteristics, rather than changing physical parameters like temperature and time
2Manufacturing precision
If acid diffusion is suppressed to improve resolution, then edge roughness is reduced, but sensitivity declines
Solution Approach 1:
The invention modifies the molecular structure parameters of the acid generator (using sulfonium salt with formula 1) to generate an acid with specific steric bulk that diffuses less, thereby improving resolution without sacrificing sensitivity
Solution Approach 2:
The resist composition uses a composite approach by combining the sulfonium salt acid generator with a specific base polymer and quencher system to achieve both high sensitivity and low acid diffusion
3Reliability
If fluorinated phenol compound is used as quencher to prevent pattern collapse, then pattern stability is improved, but acid diffusion suppression is insufficient leading to degraded LWR and CDU
Solution Approach 1:
The invention changes the chemical structure parameters of the quencher by introducing iodine atoms at specific positions (formula 2) to enhance acid diffusion suppression capability while maintaining pattern stability
Solution Approach 2:
The invention creates a composite quencher system combining fluorinated phenol compound with iodized phenol compound to achieve both pattern stability and superior LWR/CDU control
4Reliability
If sulfonium salt of fluorinated phenol compound is added to resist material, then pattern collapse is prevented, but sensitivity increases during storage due to pyrolysis
Solution Approach 1:
The invention changes the thermal stability parameters by introducing iodine atoms which strengthen the S-O bond and reduce pyrolysis tendency compared to fluorinated compounds alone
Solution Approach 2:
The composite quencher system with iodized phenol compound exhibits improved storage stability by reducing pyrolysis reactions while maintaining the pattern collapse prevention capability
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 use of the sulfonium salt of an iodized phenol compound effectively reduces acid diffusion, leading to improved sensitivity, reduced LWR, enhanced CDU, high resolution, and a wider process margin, while also maintaining storage stability.
Implementation Method 1
the sulfonium or iodonium salt capable of generating α-non-fluorinated sulfonic acid undergoes ion exchange with the α-fluorinated sulfonic acid. Through the ion exchange, the α-fluorinated sulfonic acid once generated upon light exposure is converted back to the sulfonium or iodonium salt
Implementation Method 2
a photoacid generator capable of generating a sulfonic acid which is substituted at α-position with fluorine
Data Source
AI summary
The resist composition comprises a sulfonium salt of an iodized phenol compound. The resist composition which comprises a sulfonium salt of an iodized phenol compound can exhibit a high sensitivity and forms a pattern with reduced LWR or improved CDU independent of whether it is of positive or negative type.