Negative-Type Photosensitive Polyimide for Low-Temperature Imidization
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Solution Overview
Problem
Conventional polyimide resin curing at low temperatures results in insufficient imidization, leading to inadequate chemical resistance, and negative-type photosensitive polyimides lack rigorous in-plane uniformity and resolution.
Innovation Solution
A negative-type photosensitive resin composition with a polyimide precursor having a specific weight-average molecular weight and reactive substituents, allowing imidization at low temperatures and improving film thickness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature curing is used to achieve complete imidization and high chemical resistance, then chemical resistance is improved, but chip yields deteriorate due to temperature sensitivity
Solution Approach 1:
The patent changes the molecular weight parameter of the polyimide precursor to a specific range (3,000 ≤ Mw < 16,000) to enable complete imidization at low temperatures (200°C or below), thereby achieving high chemical resistance without exposing temperature-sensitive chips to high temperatures
Solution Approach 2:
The patent replaces thermal energy input (high temperature curing) with chemical structure optimization (controlled molecular weight polyimide precursor) to achieve the same imidization effect at lower temperatures, protecting temperature-sensitive electronic components
2Productivity
If low temperature curing is used to protect chip yields, then productivity is improved, but imidization is insufficient and chemical resistance deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of the polyimide precursor to a specific range (3,000 ≤ Mw < 16,000) to enable complete imidization reaction at low temperatures (200°C or below), achieving both high chip yields and high chemical resistance simultaneously
3Measurement precision
If positive-type photosensitive polyimide is used to achieve high resolution, then measurement precision is improved, but in-plane uniformity of film thickness deteriorates due to strict uniformity requirements
Solution Approach 1:
The patent inverts the conventional approach by using negative-type photosensitive polyimide instead of positive-type, achieving high resolution through the specific molecular weight range (3,000 ≤ Mw < 16,000) while avoiding the strict in-plane uniformity requirements that plague positive-type materials
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 achieves high chemical resistance and in-plane uniformity of the resin layer, enabling effective low-temperature curing and improved pattern precision.
Implementation Method 1
a photopolymerization initiator (B)
Implementation Method 2
thermal imidization treatment involving coating, exposure, development and curing of the compositions
Data Source
AI summary
A negative-type photosensitive resin composition that has a satisfactory imidization rate and can yield a resin layer with high chemical resistance, even under low-temperature curing conditions of 200° C. or below, the negative-type photosensitive resin composition containing a photopolymerization initiator (B) in a proportion of 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of a polyimide precursor (A), the polyimide precursor (A) being a polyamic acid ester or polyamic acid salt with a specific structure, and the weight-average molecular weight (Mw) of the polyimide precursor (A) being 3,000 or greater and less than 16,000, in terms of polystyrene, according to gel permeation chromatography (GPC).