Negative Photosensitive Polyimide for Low-Shrinkage Copper Wiring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polyimide resins used in semiconductor devices face issues with cure shrinkage, poor flatness, copper adhesion, and resolution, particularly in flip-chip mounting and fan-out wafer-level packaging processes, which affect the precision and reliability of wiring in high-speed semiconductor components.
Innovation Solution
A negative photosensitive resin composition containing a specific polyimide with alicyclic structures, photopolymerizable functional groups, and a solvent, along with optional additives, is developed to enhance in-plane uniformity, reduce cure shrinkage, and improve copper adhesion and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyimide resins are used, then heat resistance and electrical properties are maintained, but cure shrinkage occurs and flatness deteriorates
Solution Approach 1:
The patent modifies the molecular structure parameters of polyimide resins by introducing specific alicyclic structures (Formula 1) with controlled molecular weight (3,000-25,000) and molecular weight distribution (1.05-1.30). This structural parameter change reduces cure shrinkage while maintaining heat resistance, achieving both reliability and manufacturing precision requirements
Solution Approach 2:
The invention creates a composite photosensitive resin composition containing multiple components: modified polyimide resin (A), unmodified polyimide resin (B), photopolymerizable compound (C), and initiator (D). This composite formulation combines the heat resistance of conventional polyimide with the low shrinkage properties of the modified component, resolving the contradiction between reliability and flatness
2Productivity
If photosensitive resin composition is applied for rewiring layer, then process reduction is achieved, but poor flatness causes resolution deterioration
Solution Approach 1:
The patent optimizes molecular weight parameters (3,000-25,000) and molecular weight distribution (1.05-1.30) of the polyimide resin to achieve optimal balance between solubility for coating uniformity and structural integrity for resolution. This parameter optimization enables high-resolution patterning while maintaining the productivity benefits of photosensitive resin processing
Solution Approach 2:
The invention introduces photopolymerizable functional groups at specific locations (end groups or side chains) of the polyimide molecule, creating local reactive sites that enable photolithography functionality without compromising the overall molecular structure's heat resistance and dimensional stability, thus maintaining both resolution and process efficiency
3Reliability
If copper wiring contacts rewiring layer, then electrical connection is achieved, but photosensitive resin must be adhesive to copper
Solution Approach 1:
The patent incorporates components with specific functional groups in the composite photosensitive resin formulation that provide copper adhesion capability while maintaining the overall composite's electrical and thermal properties, ensuring both reliable electrical connection and manufacturing precision
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 in-plane uniformity, low cure shrinkage, and strong copper adhesion, resulting in improved resolution and reliability of semiconductor device wiring.
Implementation Method 1
contains a photopolymerizable functional group... (C) a photopolymerization initiator
Implementation Method 2
ring-closing treatment (imidization or benzoxazole formation) and thermal crosslinking by application, exposure, development, and curing
Data Source
AI summary
Provided is a negative photosensitive resin composition comprising: a polyimide (A) represented by formula (1) {in formula (1), A denotes a structure derived from a tetracarboxylic dianhydride, B denotes a structure derived from a diamine, and D denotes an imide structure, Z1 and Z2 may each be the same or different, and each denotes a monovalent organic group comprising a photopolymerizable functional group and at least one linking group selected from the group consisting of an ester bond, a urea bond, and an amide bond, and the photopolymerizable functional group is present at the end of Z1 and/or Z2, l and m are integers of 0 or 1 and satisfy l+m=1, n is an integer of 1-30, and p and q are each an integer of 0-2 and satisfy p+q≥1}; a solvent (B); and a photopolymerization initiator (C).