Onium Salt Quencher for Acid Diffusion and Resist Pattern Stability
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Solution Overview
Problem
Existing chemically amplified resist compositions face challenges in achieving high sensitivity, resolution, and control of acid diffusion while minimizing pattern collapse and swelling during development, particularly for microelectronic devices at the 5-nm node and beyond.
Innovation Solution
Incorporation of an onium salt with an aromatic carboxylic acid anion having a protected hydroxy group and a pentafluorosulfanyl group attached to adjacent carbon atoms, functioning as a quencher to control acid diffusion and enhance lithography properties such as LWR, CDU, and DOF, while preventing pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed to improve resolution, then manufacturing precision is improved, but sensitivity deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the quencher by introducing a pentafluorosulfanyl group and protecting hydroxy group into the aromatic carboxylic acid structure. This molecular modification enables the quencher to achieve both high acid diffusion control capability and high sensitivity, resolving the traditional trade-off between resolution and sensitivity in chemically amplified resist compositions.
2Manufacturing precision
If temperature and time of post exposure bake are reduced to minimize acid diffusion, then manufacturing precision is improved, but sensitivity and contrast deteriorate
Solution Approach 1:
The invention changes the chemical structure parameters of the quencher molecule by incorporating specific functional groups (pentafluorosulfanyl group and protected hydroxy group). This structural modification enables effective acid diffusion control at reduced PEB temperature and time while maintaining high sensitivity and contrast, thus resolving the contradiction between manufacturing precision and productivity.
3Manufacturing precision
If conventional quenchers are used to control acid diffusion, then manufacturing precision is improved, but pattern collapse and swelling occur during development
Solution Approach 1:
The invention creates a composite functional structure within the quencher molecule by combining multiple functional groups (aromatic carboxylic acid core, pentafluorosulfanyl group, and protected hydroxy group) into a single integrated molecule. This composite structure provides both acid diffusion control capability and pattern stability during development, preventing pattern collapse and swelling while maintaining manufacturing precision.
Solution Approach 2:
The invention modifies the chemical parameters of the quencher by introducing the pentafluorosulfanyl group and protected hydroxy group into the aromatic carboxylic acid structure. These parameter changes enhance both the acid diffusion control capability and the pattern stability during development, resolving the contradiction between manufacturing precision and reliability.
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 improves sensitivity, resolution, and lithography properties, reducing swelling and pattern collapse, enabling precise fine processing with high-resolution and rectangular pattern profiles.
Implementation Method 1
the sulfonium salt or the iodonium salt capable of generating a sulfonic acid which is substituted at α-position with a fluorine atom undergoes ion exchange with the sulfonic acid which is substituted at α-position with a fluorine atom. Through the ion exchange, the sulfonic acid which is substituted at α-position with a fluorine atom once generated upon light exposure is converted back to the sulfonium salt or the iodonium salt.
Implementation Method 2
An acid labile group used in a (meth)acrylate polymer for an ArF resist composition undergoes a deprotection reaction when a photoacid generator capable of generating a sulfonic acid which is substituted at α-position with a fluorine atom is used
Implementation Method 3
when a photoacid generator capable of generating a sulfonic acid which is substituted at α-position with a fluorine atom is used
Data Source
AI summary
The onium salt can be used for a chemically amplified resist composition. The resist composition exhibits a high sensitivity, high resolution, having improved lithography properties such as LWR of line patterns, CDU of hole patterns, exposure latitude (EL), and depth of focus (DOF), and capable of suppressing collapse of resist patterns in photolithography using high-energy radiation such as a far ultraviolet ray, EUV, or an electron beam (EB) independent of whether it is of positive or negative tone, and to provide a pattern forming process. The onium salt having the formula (1).