Photosensitive Resin Composition for Void-Free Substrate Joining

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In the fields of MEMS and semiconductor packages, the high storage modulus of resin compositions at joining temperatures leads to void generation when a glass or silicon substrate is joined, resulting in poor joining quality and reliability issues.

Innovation Solution

An alkali-developing type photosensitive resin composition is developed, comprising a polycarboxylic acid resin obtained by reacting a bifunctional bisphenol epoxy resin with a monocarboxylic acid compound and a polybasic acid anhydride, combined with an epoxy resin and a photoacid generating agent, with specific addition ratios to achieve low storage modulus and excellent joining properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If resin composition is used for sealing and joining in MEMS and semiconductor packages, then production cost is reduced and dimensional accuracy is improved, but storage modulus at high temperatures becomes high causing void generation during substrate joining

Engineering Contradiction:
Improveproduction costVSAvoidjoining quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the resin by incorporating specific ratios of polycarboxylic acid resin (30-70 parts), epoxy resin (30-70 parts), and silane coupling agent (1-10 parts). This parameter optimization reduces the storage modulus at high temperatures, preventing void generation during substrate joining while maintaining the cost and dimensional accuracy advantages of resin sealing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite resin composition by combining multiple resin components (polycarboxylic acid resin, epoxy resin, and silane coupling agent) in specific proportions. This composite approach achieves a balanced performance profile with reduced storage modulus, improved joining quality, and maintained cost-effectiveness.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If resin composition has high storage modulus at joining temperature, then structural stability is maintained, but voids are generated in substrate interior and periphery during joining

Engineering Contradiction:
Improvestructural stabilityVSAvoidjoining precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent adjusts the rheological parameters of the resin composition by controlling the molecular weight distribution and crosslinking density through specific resin selections and ratios. This parameter change reduces storage modulus at joining temperatures, allowing the resin to flow and fill substrate unevenness without compromising overall structural stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces silane coupling agent (1-10 parts) that provides localized chemical bonding at the substrate-resin interface. This local quality enhancement improves joining precision by creating strong adhesion at the interface while the bulk resin maintains appropriate flexibility to prevent void generation.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If alkali-developing type photoresist is used to satisfy high aspect ratio requirements, then development capability is improved, but storage modulus remains high causing void generation during joining

Engineering Contradiction:
Improvedevelopment capabilityVSAvoidjoining reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent develops a composite photoresist system combining polycarboxylic acid resin (providing alkali developability), epoxy resin (providing structural integrity), and silane coupling agent (providing adhesion). This composite formulation achieves high aspect ratio capability through improved development characteristics while simultaneously reducing storage modulus to prevent void generation during joining, thereby enhancing joining reliability.

Inventive Principle:
Principle #40Composite 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 resin composition exhibits high sensitivity, resolution, thermal stability, and chemical resistance, preventing void formation during substrate joining and enhancing the reliability of MEMS and semiconductor packages.

Implementation Method 1

a photoacid generating agent (C)

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS9223212B2Photosensitive resin composition and cured product thereof
Publication Date: 2015.12.29 NIPPON KAYAKU CO LTD

AI summary

An alkali-developing-type photosensitive resin composition comprising: a polycarboxylic acid resin (A) obtained by reacting a polybasic anhydride (c) with a reactant (ab) between a difunctional bisphenol epoxy resin (a) having an epoxy group at both terminals and an epoxy equivalent of 600-1300 g/eq., and a monocarboxylic acid compound (b) having an alcoholic hydroxyl group; an epoxy resin (B) having two or more epoxy groups in a molecule; and a photoacid generator (C), wherein the addition ratio the monocarboxylic acid compound (b) with respect to 1 equivalent of the epoxy group of the epoxy resin (a) is 80 equivalent % or more, and the addition ratio the polybasic anhydride with respect to one equivalent of the primary hydroxyl group of the reactant (ab) is 80 equivalent % or more.