Bisphenol Polyurethane Photoimageable Composition for PCB Plating Resistance

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Solution Overview

Problem

Photoimageable compositions for printed circuit boards face limitations in electroplating resistance, tensile strength, alkaline etching resistance, gold plating resistance, and nickel plating resistance, which restrict their application in printed circuit board processes.

Innovation Solution

A novel polymer with a specific structure, derived from the polymerization of a dihydric alcohol with a bisphenol group, a diisocyanate, and an acrylate alcohol compound, is used to create a negative-acting photoimageable composition that enhances the flexibility, toughness, and resistance properties of the composition, improving its performance in covering pores and withstanding various plating processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional photoimageable compositions are used, then the basic photoresist function is achieved, but the tensile strength and ductility are insufficient

Engineering Contradiction:

Improvetensile strengthVSAvoidflexibility and toughness

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent uses a composite polymer structure containing both aromatic rings (for strength) and alkoxy/lactone functional groups (for flexibility). This composite molecular structure simultaneously achieves high tensile strength and good flexibility/toughness, resolving the contradiction between strength and reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces specific functional groups at different positions within the polymer chain: aromatic rings provide local rigidity and strength, while alkoxy and lactone groups provide local flexibility. This local differentiation of material properties throughout the polymer structure achieves both high tensile strength and good toughness.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the photoimageable composition is made more flexible to improve stripping ability, then the stripping capacity is enhanced, but the tensile strength may be reduced

Engineering Contradiction:

Improvestripping abilityVSAvoidtensile strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent creates a composite polymer where rigid aromatic segments provide tensile strength while flexible alkoxy and lactone segments provide stripping ability. This composite structure allows the material to be both strong and easily stripable, resolving the contradiction between strength and ease of operation.

Inventive Principle:

Principle #40Composite materials

3Reliability

If the photoimageable composition is designed for high electroplating resistance, then the electroplating capacity is improved, but the overall processability may be limited

Engineering Contradiction:

Improveelectroplating resistanceVSAvoidprocessability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent designs a multi-functional polymer that simultaneously provides electroplating resistance, alkaline etching resistance, gold plating resistance, nickel plating resistance, and good mechanical properties. This universal polymer structure enables the photoimageable composition to perform multiple functions, resolving the contradiction between specialized performance and overall processability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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-based photoimageable composition demonstrates improved tensile strength, electroplating resistance, alkaline etching resistance, gold plating resistance, and nickel plating resistance, enabling better processability and performance in printed circuit board manufacturing.

Implementation Method 1

the polyurethane that has a bisphenol group is one of the important components which can improve the flexibility and toughness of the photoimageable composition, and will improve not only the tensile properties, but also the capacities of electroplating resistance, alkaline etching resistance, gold plating resistance, and nickel plating resistance

Methodology Applied

Scientific EffectMolecular chain interaction:

Implementation Method 2

adding an aromatic ring functional group to the polyurethane (meth)acrylate to enhance the tensile strength and ductility of the photoimageable composition due to the rigidity of the aromatic ring

Methodology Applied

Scientific EffectRigidity of aromatic ring:

Implementation Method 3

adding an alkoxy functional group and an ring-opened lactone functional group to a polyurethane (meth)acrylate to increase the chain length, and thus to enhance the flexibility of the photoimageable composition

Methodology Applied

Scientific EffectChain length extension:

Data Source

PatentUS8835522B2Polyurethane polymer having bisphenol group and photoimageable composition containing the same

Publication Date: 2014.09.16 ETERNAL MATERIALS CO LTD

AI summary

The present invention provides a polymer having the structure of formula (I)wherein n, R1, R2, R3, R4, R5, R6, a, b and c are as defined in the specification. The present invention also provides a negative-acting photoimageable composition comprising the above-mentioned polymer of formula (I), which is suitable for the fabrication of printed circuit boards.