Photosensitive Polyimide Composition for Thick Relief Pattern Adhesion

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Solution Overview

Problem

Photosensitive polyimide resins used in ELK protective layers exhibit weak adhesiveness to semiconductor electrodes, leading to delamination and insufficient light absorption, making it difficult to form thick films with satisfactory patterns and mechanical properties.

Innovation Solution

A photosensitive resin composition comprising a polyimide precursor with specific chemical structures in side chains, combined with a photoradical initiator, to enhance adhesiveness and form thick film patterns with improved mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If photosensitive polyimide resin with linear structure backbone is used to form thick film, then film thickness is increased, but light absorption at i-line becomes high and crosslinking efficiency at film bottom layer becomes insufficient

Engineering Contradiction:

Improvefilm thicknessVSAvoidpattern shape quality

Core Design Contradiction:

Length of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies local quality by modifying only the side chain structures of the polyimide resin while maintaining the linear backbone. Specific side chains with particular chemical groups are introduced to reduce light absorption at the i-line wavelength, enabling sufficient light penetration to the bottom layer of thick films (9 μm or greater) while preserving the mechanical properties provided by the linear backbone structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the chemical parameters of the polyimide resin by selecting specific side chain compositions and structures. The side chains are designed with specific chemical groups that have low absorption coefficients at the i-line wavelength, thereby changing the optical parameters of the resin to enable deep light penetration and uniform crosslinking throughout thick film sections.

Inventive Principle:

Principle #35Parameter changes

2Strength

If photosensitive polyimide resin is used for ELK protective layer, then heat resistance and mechanical properties are improved, but adhesiveness to aluminum electrodes becomes weak

Engineering Contradiction:

Improvemechanical propertiesVSAvoidadhesiveness

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent creates a composite structure within the polyimide resin by combining the linear backbone (providing mechanical strength and heat resistance) with specifically designed side chains (providing adhesion). The side chains contain functional groups that interact with aluminum electrodes, creating a composite material that simultaneously achieves both mechanical properties and adhesiveness.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent segments the polyimide resin structure into distinct functional components: the linear backbone segment provides mechanical strength and heat resistance, while the side chain segment provides adhesiveness to aluminum electrodes. This segmentation allows each part to independently fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

3Stress or pressure

If polyimide resin with polymerizable groups on side chains is used, then low stress cured film is formed, but adhesiveness to substrate deteriorates

Engineering Contradiction:

Improveinternal stressVSAvoidadhesiveness

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

The patent applies local quality by placing polymerizable groups at specific locations within the side chains rather than throughout the entire molecule. The side chains are designed with particular chemical groups at specific positions that enable low stress curing while maintaining substrate adhesion, resolving the contradiction between stress reduction and adhesiveness.

Inventive Principle:

Principle #3Local quality

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 excellent adhesiveness with substrates, allowing the formation of thick film patterns with enhanced mechanical properties and reliability in semiconductor devices.

Implementation Method 1

a photosensitive resin composition comprising: (A) a polyimide precursor having a repeating structure represented by following formula (1)... and (B) a photoradical initiator

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS20260036904A1Photosensitive resin composition, method for producing cured relief pattern, and semiconductor device

Publication Date: 2026.02.05 ASAHI KASEI KOGYO KABUSHIKI KAISHA

AI summary

The present invention provides a photosensitive resin composition which contains (A) a polyimide precursor that has a repeating structure represented by formula (1), and (B) a photoradical initiator. (In formula (1), X1 represents a tetravalent organic group; Y1 represents a divalent organic group; m represents an integer of 1 or more; R1 and R2 each represent a hydrogen atom, a radically polymerizable group or an organic group represented by formula (2). In formula (2), R3, R4 and Rz each independently represent a monovalent organic group having 2 to 20 carbon atoms and not containing a fluorine atom, or alternatively, in cases where one of the R3, R4 and Rz moieties is a hydrogen atom, the other moieties are each a monovalent organic group having 2 to 20 carbon atoms and not containing a fluorine atom, and at least one of the other moieties has a branched chain or a cyclic structure.)