Photoacid Salt Structure for Uniform Resist Pattern Dimensions
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Solution Overview
Problem
Existing resist compositions fail to achieve satisfactory CD uniformity in resist patterns.
Innovation Solution
A novel salt represented by formula (I) is used in a resist composition, which includes a specific acid generator and a resin with acid-labile groups, combined with a method involving application, drying, exposure, and heating to form a resist pattern with improved CD uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional salts are used in resist compositions, then the resist pattern can be formed, but the CD uniformity is insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the salt component in the resist composition. Specifically, it uses salts with furan or thiophene rings substituted with electron-withdrawing groups (such as fluorine, chlorine, bromine, iodine, or cyano groups) at specific positions. This structural parameter change optimizes the acid generation efficiency and improves CD uniformity while maintaining reliable pattern formation.
Solution Approach 2:
The patent employs composite materials by combining specific salt components with resin components having acid-labile groups. The resist composition is formulated as a composite system where the novel salt (with furan/thiophene structure and electron-withdrawing groups) works synergistically with the resin to achieve both satisfactory pattern formation and improved CD uniformity.
2Manufacturing precision
If existing acid generators are used, then the resist composition can be prepared, but satisfactory CD uniformity cannot be achieved
Solution Approach 1:
The patent changes the chemical parameters of the acid generator by using salts with specific structural features: furan or thiophene rings with electron-withdrawing groups at designated positions. This structural modification enhances the acid generation performance and CD uniformity while maintaining ease of manufacture through standard resist composition preparation methods.
3Manufacturing precision
If conventional resist compositions are used, then the basic patterning function is achieved, but CD uniformity remains insufficient
Solution Approach 1:
The patent optimizes the chemical parameters of the salt component by introducing furan/thiophene rings with electron-withdrawing groups at specific positions. This targeted parameter change improves CD uniformity while maintaining relatively simple composition structure and standard preparation procedures.
Solution Approach 2:
The patent applies local quality by placing electron-withdrawing groups (such as fluorine, chlorine, bromine, iodine, or cyano groups) at specific positions (R1-R8) on the furan or thiophene ring structure. This localized structural modification at key positions enhances acid generation efficiency and CD uniformity without requiring complex overall composition changes.
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 pattern produced exhibits enhanced CD uniformity, addressing the limitations of previous compositions.
Implementation Method 1
a salt... wherein... AI− represents an organic anion... An acid generator comprising the salt... a resist composition comprising the acid generator and a resin having an acid-labile group
Implementation Method 2
(4) a step of heating the exposed composition layer
Data Source
AI summary
A salt capable of producing a resist pattern with satisfactory CD uniformity (CDU) represented by formula (I), an acid generator and a resist composition including the same:wherein R4, R5, R7 and R8 each represent a halogen atom, a haloalkyl group, etc., A1 and A2 each represent a hydrocarbon group, the group may have a substituent, —CH2— in the group may be replaced by —O—, —CO—, —S—, —SO2—, etc., X3 and X4 each represent —O— or —S—, m1 present an integer of 1 to 5, m2 and m8 represent an integer of 0 to 5, m4 and m5 represent an integer of 0 to 3, m7 represent an integer of 0 to 4, 1≤m1+m7≤5, 0≤m2+m8≤5, and AI− represents an organic anion.