Chemically Amplified Resist Composition for Low LWR and High Sensitivity
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Solution Overview
Problem
Current negative resist compositions face challenges in achieving high sensitivity and reduced line width roughness (LWR) and critical dimension uniformity (CDU) while minimizing top loss and acid diffusion, especially when used in alkaline development processes for microelectronic device manufacturing.
Innovation Solution
A chemically amplified negative resist composition incorporating an onium salt with a specific partial structure as an acid generator, combined with a base polymer having specific recurring units, enhances sensitivity and dissolution contrast, leading to improved LWR and CDU with minimal top loss during alkaline development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the acid diffusion distance is reduced to improve LWR or CDU, then sensitivity becomes lower
Solution Approach 1:
The patent introduces a base polymer with dual functionality: units (B1) that provide alkaline solubility in unexposed regions and units (B2) that become insoluble when exposed to acid. This local differentiation allows the resist to maintain high dissolution contrast while controlling acid diffusion, resolving the contradiction between LWR/CDU improvement and sensitivity maintenance.
Solution Approach 2:
The patent uses a composite base polymer structure combining two types of recurring units with different chemical properties. Unit (B1) contains hydroxyl groups for alkaline solubility, while unit (B2) contains acid-labile groups that crosslink or precipitate upon acid exposure. This composite structure enables simultaneous achievement of low LWR/CDU and high sensitivity.
2Manufacturing precision
If the PEB temperature becomes lower to improve LWR or CDU, then sensitivity becomes lower
Solution Approach 1:
The patent changes the chemical parameter of the base polymer by introducing specific recurring units with hydroxyl groups and acid-labile groups. This chemical modification allows the system to achieve low LWR/CDU at lower PEB temperatures without sacrificing sensitivity, as the acid-generated insolubilization mechanism works efficiently at lower temperatures.
3Manufacturing precision
If the amount of quencher added is increased to improve LWR or CDU, then sensitivity becomes lower
Solution Approach 1:
The patent extracts the dissolution control function from the quencher and assigns it to the base polymer itself. By incorporating units (B1) that provide inherent alkaline solubility and units (B2) that provide acid-induced insolubility, the system achieves LWR/CDU control without relying on external quenchers, thereby maintaining high sensitivity.
4Reliability
If a negative resist composition is used wherein exposed regions are insolubilized to avoid mask degradation, then the exposed region dissolves during alkaline development causing pattern top loss
Solution Approach 1:
The patent creates local quality differentiation within the base polymer: units (B1) remain soluble in alkaline developer while units (B2) become insoluble upon acid exposure. This allows the exposed region to be retained (forming negative patterns) while preventing top loss, as the crosslinked/precipitated structure resists alkaline dissolution.
Solution Approach 2:
Instead of making the entire exposed region insoluble (which causes top loss), the patent inverts the approach by making only specific functional units (B2) insoluble while keeping other units (B1) soluble. This selective insolubilization maintains pattern integrity while preventing top loss during alkaline development.
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 high sensitivity and improved pattern profiles with reduced LWR and CDU, along with controlled acid diffusion, resulting in better pattern formation and reduced top loss during alkaline development.
Implementation Method 1
an onium salt having a partial structure represented by formula (A) The chemically amplified negative resist composition comprises the photoacid generator
Data Source
AI summary
An onium salt having a partial structure of formula (A) is provided wherein Ra1 and Ra2 are hydrogen or a C1-C10 hydrocarbyl group in which hydrogen may be substituted by halogen and —CH2— may be replaced by —O— or —C(═O)—, both Ra1 and Ra2 are not hydrogen at the same time, Ra1 and Ra2 may bond together to form an aliphatic ring. A chemically amplified negative resist composition comprising the onium salt as acid generator forms a pattern of good profile having a high sensitivity, improved dissolution contrast, reduced LWR and improved CDU.