Citraconimide Underfill Composition for Low-Loss Chip Mounting

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Solution Overview

Problem

Current underfill materials for semiconductor chip mounting, such as epoxy resins, exhibit high relative permittivity and dielectric tangent, leading to increased transmission loss and material warpage, and lack suitable adhesiveness and infiltration properties for high-frequency applications.

Innovation Solution

An underfill composition comprising a citraconimide compound, epoxy resin, epoxy resin curing agent, curing accelerator, and inorganic filler, specifically designed to achieve low relative permittivity, low dielectric tangent, and enhanced adhesiveness, with the citraconimide compound being a key component that improves compatibility and dielectric properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If epoxy resin is used as underfill material, then good adhesiveness and structural strength are achieved, but high relative permittivity and dielectric tangent cause increased transmission loss and material warpage

Engineering Contradiction:

ImproveadhesivenessVSAvoidtransmission loss

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite resin system combining epoxy resin with citraconimide compound and polyphenylene ether. This composite approach allows the material to achieve low dielectric properties (relative permittivity 3.0 or less, dielectric tangent 0.01 or less) while maintaining good adhesiveness and structural strength, resolving the contradiction between adhesiveness and transmission loss.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If heat-curable resins or thermoplastic resins are used to achieve low relative permittivity and dielectric tangent, then dielectric properties are improved, but high melt viscosity and hard/brittle cured products make them unsuitable for semiconductor encapsulation

Engineering Contradiction:

Improvedielectric propertiesVSAvoidinfiltration property

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent modifies the resin composition by incorporating citraconimide compound with specific molecular weight (200-10,000) and controlling the ratio of resin components. This parameter optimization achieves low dielectric properties while maintaining low melt viscosity and good infiltration properties, making the material suitable for semiconductor encapsulation applications.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional underfill materials are used, then manufacturing process is simple, but high relative permittivity causes material warpage and reduced manufacturing yield

Engineering Contradiction:

Improveprocess simplicityVSAvoidsubstrate manufacturing yield

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent develops a composite underfill material combining epoxy resin, citraconimide compound, and polyphenylene ether that achieves low relative permittivity (3.0 or less) and low dielectric tangent (0.01 or less). This composite formulation reduces material warpage and improves substrate manufacturing yield while maintaining ease of manufacture through conventional processing methods.

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 composition demonstrates superior infiltration properties and excellent dielectric properties with low relative permittivity and dielectric tangent, along with improved adhesiveness, making it suitable for high-frequency applications and reducing material warpage.

Implementation Method 1

there is a demand for underfill materials possessing low-dielectric properties such as low relative permittivity and low dielectric tangent, which enable minimization of transmission loss during signal propagation

Methodology Applied

Scientific EffectDielectric permittivity: Dielectric Permittivity

Implementation Method 2

an underfill material with a low Coefficient of Linear Thermal Expansion (CTE) is highly regarded for mitigating material warpage and improving substrate manufacturing yield

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

an epoxy resin curing agent reactive with the epoxy groups

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS20240425718A1Underfill composition

Publication Date: 2024.12.26 SHIN ETSU CHEMICAL CO LTD

AI summary

Provided is an underfill composition having a low relative permittivity and a low dielectric tangent. The underfill composition contains the components of: (A) a citraconimide compound; (B) an epoxy resin; (C) an epoxy resin curing agent; (D) a curing accelerator, and (E) an inorganic filler, wherein the citraconimide compound (A) is a biscitraconimide compound represented by the following formula (1):wherein A in the formula (1) represents a divalent organic group.