Resist Composition Acid Diffusion Control
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Solution Overview
Problem
Current resist compositions face challenges in achieving high resolution and low defect rates during photolithography, particularly with the use of high energy beams, due to issues with acid diffusion and solubility, leading to problems like line edge roughness and pattern instability.
Innovation Solution
A resist composition incorporating a sulfonium salt with a specific partial structure and a polymer compound containing specific repeating units, which regulates acid diffusion and improves solubility, is developed. This composition includes a sulfonium salt with a cation and anion pair and a polymer with acid-decomposable units, enhancing lithography performance and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional resist compositions are used for high energy beam lithography, then exposure and development can be performed, but acid diffusion causes line edge roughness and pattern instability
Solution Approach 1:
A glass transition type regulator comprising a cyclic carbonate structure is introduced as an intermediary substance. This regulator mediates between the acid generator and the resin, controlling acid diffusion while maintaining pattern stability. The cyclic carbonate structure specifically regulates the movement of acid during the baking process, preventing both excessive diffusion (which causes LER) and insufficient diffusion (which causes pattern instability).
Solution Approach 2:
The glass transition temperature (Tg) of the resist composition is adjusted by adding the cyclic carbonate regulator. This parameter change optimizes the acid diffusion characteristics during baking. By controlling Tg, the composition achieves balanced acid diffusion that simultaneously reduces line edge roughness and maintains pattern stability throughout the exposure and development process.
2Stability of the object's composition
If acid diffusion is increased to improve development uniformity, then pattern stability improves, but line edge roughness increases
Solution Approach 1:
The glass transition temperature is optimized to a specific range through the addition of cyclic carbonate regulator. This Tg optimization creates an ideal balance where acid diffusion is sufficient for pattern stability but limited enough to maintain sharp line edges. The regulator enables this precise parameter control that cannot be achieved with conventional resist compositions.
Solution Approach 2:
The resist composition is formulated as a composite system combining the cyclic carbonate regulator with specific resins and acid generators. This composite structure allows the regulator to perform its dual function of controlling acid diffusion for both pattern stability and line edge quality, achieving what single-component systems cannot accomplish.
3Reliability
If conventional polymers are used for chemically amplified resist, then solubility and etching resistance can be achieved, but acid diffusion control is insufficient leading to LER and LWR
Solution Approach 1:
The cyclic carbonate regulator acts as an intermediary that modifies the interaction between acid and polymer chains. It controls the diffusion pathway of acid through the resin matrix, preventing the random diffusion that causes LER and LWR while still allowing sufficient acid reach for complete deprotection and development uniformity.
Solution Approach 2:
The addition of cyclic carbonate regulator changes the thermal and diffusion parameters of the resist system. By adjusting the glass transition temperature and acid mobility, the composition achieves optimal balance between etching resistance (maintained by polymer structure) and line width control (improved by regulated acid diffusion).
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 achieves improved lithography performance with reduced line edge roughness, line width roughness, and critical dimension uniformity, while minimizing defects and pattern instability, making it suitable for high-resolution microprocessing technologies.
Implementation Method 1
a sulfonium salt having a specific partial structure... which uses an acid as a catalyst... high energy beams such as ultraviolet ray, deep ultraviolet ray, and electron beam (EB) are used as an exposure light source
Implementation Method 2
regulation of the acid diffusion, which significantly affects resolution of the chemically amplified resist film... This time-dependent change is mostly caused by diffusion of an acid generated by exposure
Implementation Method 3
a chemically amplified resist composition, which uses an acid as a catalyst... an acid-labile protective group that masks an acidic functional group... This protective group deprotects by an acid catalyst generated from a photo acid generator
Data Source
AI summary
The present invention provides a resist composition, including: (A) a sulfonium salt containing an anion and a cation, the cation including a partial structure shown by the following general formula (A1); and (B) a polymer compound containing a repeating unit shown by the following general formula (B1). The present invention provides a resist composition that causes few defects and is excellent in lithography performance, having regulated acid diffusion, in photolithography using a high energy beam as a light source, and a resist patterning process using this resist composition.