Negative Photosensitive Composition for High-Resolution Patterning
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Solution Overview
Problem
Non-antimony-based cationic polymerization initiators used in negative photosensitive compositions are highly sensitive, making it difficult to optimize their addition for high-resolution patterning, and they generate strong acids, which lowers the cross-linking rate and patterning performance.
Innovation Solution
A negative photosensitive composition containing an epoxy group-containing resin and a cationic polymerization initiator with specific chemical formulas, where the initiator generates acids with a pKa of -3 or more, allowing for adjusted sensitivity and improved cross-linking rates for high-resolution pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If non-antimony-based cationic polymerization initiators are used to eliminate environmental concerns, then environmental safety is improved, but the high sensitivity makes it difficult to optimize addition amount for high-resolution patterning
Solution Approach 1:
The patent changes the chemical structure parameters of the cationic polymerization initiator by selecting specific onium salts (sulfonium, phosphonium, or iodonium salts) with particular counterions (BF4-, PF6-, CF3SO3-, B(C6F5)4-). This structural parameter change adjusts the sensitivity and acid generation characteristics to achieve both environmental safety and high-resolution patterning capability.
2Productivity
If non-antimony-based cationic polymerization initiators generate strong acids to ensure reactivity, then polymerization efficiency is improved, but the cross-linking rate decreases and patterning performance deteriorates
Solution Approach 1:
The patent optimizes the acid strength parameter by selecting onium salts with specific counterions that have pKa values within the range of -10 to 0. This parameter change balances the reactivity needed for polymerization efficiency with the cross-linking rate required for good patterning performance, avoiding excessively strong acids that would harm pattern formation.
Solution Approach 2:
The patent uses composite onium salt structures combining different cationic parts (sulfonium, phosphonium, or iodonium) with specific anionic parts (BF4-, PF6-, CF3SO3-, B(C6F5)4-). This composite approach creates initiators with balanced properties that simultaneously achieve good polymerization efficiency and patterning performance.
3Adaptability or versatility
If epoxy group-containing resin is used as base material to enable cationic polymerization, then negative photoresist functionality is achieved, but the sensitivity optimization becomes difficult with non-antimony initiators
Solution Approach 1:
The patent changes the operational parameters by establishing specific addition amount ranges (0.01-10 wt% of the onium salt relative to epoxy resin) and optimizing exposure conditions. This makes the system easier to operate with predictable sensitivity characteristics, eliminating the optimization difficulties associated with non-antimony initiators.
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 composition enables the formation of high-resolution patterns with excellent shape retention and reduced roughness, achieving appropriate sensitivity and cross-linking rates.
Implementation Method 1
a cationic polymerization initiator (B) and wherein the film is subjected to selective exposure with radiation such as light or electron beams, and developing treatment is performed
Data Source
AI summary
A negative photosensitive composition includes an epoxy group-containing resin (A); and a cationic polymerization initiator (B), in which the cationic polymerization initiator (B) has one or more types of cationic polymerization initiator (B0) selected from the group consisting of a compound represented by formula (b0-1) and a compound represented by formula (b0-2), and a cationic polymerization initiator (B1) which generates an acid having a pKa of -3 or more. In the formulae, Rb01 to Rb04 are each independently a fluorine atom or an aryl group which may have a substituent, Rb05 is a fluorine atom or a fluorinated alkyl group which may have a substituent, a plurality of Rb05's may be the same as or different from each other, q is an integer of 1 or more, and Qq+'s are each independently a q-valent organic cation.