Photosensitive Polyimide Resin for Fine Patterning Without Fluoroalkyls
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Solution Overview
Problem
Existing photosensitive polyimide-based materials face challenges in achieving high solvent solubility and resolution for fine pattern formation without using fluoroalkyl groups, which are environmentally hazardous and subject to regulatory restrictions.
Innovation Solution
A polyimide-based polymer with structural units represented by general formulas (1) and (2) that are soluble in aqueous alkaline solutions, used in positive and negative photosensitive resin compositions, enhancing solvent solubility and enabling high-resolution pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fluoroalkyl groups are incorporated into the polymer structure to improve solvent solubility, then solvent solubility is improved, but environmental safety deteriorates due to health hazards and regulatory restrictions
Solution Approach 1:
The invention changes the chemical structure parameters by replacing fluoroalkyl groups with sulfone groups (–SO2–) and fluorine-substituted phenolic hydroxy groups. This structural parameter change maintains solvent solubility through the sulfone group's polar aprotic nature while eliminating the environmental hazards associated with perfluoroalkyl compounds.
Solution Approach 2:
The invention uses alternative chemical groups (sulfone and fluorine-substituted phenolic hydroxy) that serve the same functional purpose as fluoroalkyl groups but without the environmental persistence and toxicity issues, effectively replacing harmful substances with safer alternatives.
2Reliability
If high temperature imidization exceeding 300°C is performed to obtain polyimide film, then polyimide film quality is improved, but substrate damage occurs due to high temperature constraints and copper wiring oxidation
Solution Approach 1:
The invention introduces photoacid generator and photosensitive groups into the polyimide structure beforehand, enabling the material to undergo chemical changes upon light exposure. This preliminary action allows subsequent low-temperature curing to achieve the desired film properties without requiring high-temperature imidization that would damage the substrate.
Solution Approach 2:
The invention replaces the thermal energy-based imidization process with a photochemical process. By incorporating photosensitive groups that generate acid upon light exposure, the curing mechanism shifts from thermal to photochemical, enabling low-temperature processing that protects temperature-sensitive substrates and copper wiring.
3Productivity
If finer patterning is implemented for densification and integration, then integration density is improved, but manufacturing precision requirements increase due to resolution demands
Solution Approach 1:
The invention changes the chemical parameters by introducing specific photosensitive groups (diazo compounds, triarylsulfonium salts, iodonium salts) with different sensitivities and resolution characteristics. This allows optimization of the photosensitive resin composition to achieve high resolution patterning suitable for finer integration densities.
Solution Approach 2:
The invention creates a composite photosensitive resin composition containing polyimide base resin, photoacid generator, and photosensitive groups in specific ratios. This composite material combines the heat resistance and mechanical properties of polyimide with the high-resolution patterning capabilities of the photosensitive components, enabling both fine patterning and substrate protection.
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 polymer allows for fine pattern formation with high resolution and excellent mechanical properties, adhesiveness, and heat resistance, suitable for interlayer insulating and surface protective films in semiconductor elements.
Implementation Method 1
The polymer has favorable solvent solubility and is soluble in an aqueous alkaline solution
Data Source
AI summary
A polymer in the present invention contains a structural unit represented by the following general formula (1), where X1 is a tetravalent organic group, Z1 is a divalent organic group, and “k” is an integer of 1 to 3. Thus, the present invention provides: a positive photosensitive resin composition and a negative photosensitive resin composition which exhibit favorable solvent solubility and are capable of forming a fine pattern with high resolution as a result of solubility in an aqueous alkaline solution; a polyimide-based polymer usable as a base resin for these compositions; and a patterning method and a method for forming a cured film which use the compositions.