Conductive Adhesive Film for Heat-Resistant Semiconductor Die Bonding

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Solution Overview

Problem

Current lead-free bonding materials for semiconductor devices face challenges in achieving both high heat resistance and mounting reliability due to poor wettability and stress relaxation properties, and existing fluxes are prone to moisture absorption and bleed-out, affecting reflow resistance and electrical conductivity.

Innovation Solution

An electrically conductive adhesive agent composition combining specific metal particles, such as copper, nickel, or tin, with an organophosphorus compound, along with a thermosetting resin, which forms a high-melting intermetallic compound after sintering, enhancing heat resistance and mounting reliability while minimizing moisture absorption and bleed-out.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If lead-free bonding materials with high melting points are used to improve heat resistance, then heat resistance is improved, but wettability deteriorates and mounting reliability decreases

Engineering Contradiction:
Improveheat resistanceVSAvoidmounting reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the bonding material by incorporating specific organometallic compounds with controlled carbon chain lengths and functional groups, enabling the material to exhibit both high-temperature stability and good wettability properties that were previously mutually exclusive

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite bonding material system combining traditional flux components with specially designed organometallic compounds, achieving synergistic effects where the composite material provides both the heat resistance of high-melting materials and the wettability of lower-melting materials

Inventive Principle:
Principle #40Composite materials

2Reliability

If diffusion sintering-type solders are used to reduce melting point and improve wettability, then mounting reliability is improved, but stress relaxation properties deteriorate due to hardness and brittleness

Engineering Contradiction:
Improvemounting reliabilityVSAvoidstress relaxation properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention modifies the physical and chemical parameters of the sintered material by controlling particle size distribution, sintering temperature, and organic additive composition, transforming the material from a hard and brittle state to a more ductile state with improved stress relaxation capabilities

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces organic compounds as intermediary substances that act as binders and stress-distributing agents within the sintered structure, mediating between the rigid metal particles and the external mechanical stresses, thereby improving overall stress relaxation properties

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional fluxes are used to improve wettability, then mounting reliability is improved, but moisture absorption and bleed-out increase, affecting reflow resistance

Engineering Contradiction:
Improvemounting reliabilityVSAvoidmoisture absorption and bleed-out
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention replaces conventional fluxes with organometallic compounds that perform the flux function temporarily during bonding but do not require removal, effectively making the flux function disposable and eliminating the harmful effects of moisture absorption and bleed-out that characterize traditional fluxes

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention extracts and eliminates the harmful moisture-absorbing and bleeding properties from the bonding material system while retaining the essential wettability-enhancing function, creating a material that performs flux duties without the associated drawbacks

Inventive Principle:
Principle #2Taking out (Extraction)

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 heat resistance and mounting reliability, with improved moisture absorption resistance and reflow resistance, preventing delamination and maintaining electrical conductivity, even after thermal cycles.

Implementation Method 1

an organophosphorus compound which has a function of removing an oxide film formed on a metal

Methodology Applied
Scientific EffectChemical reduction: Reduction

Implementation Method 2

studies on diffusion sintering-type solders such as Cu-based and Sn-based solders have been pursued

Methodology Applied
Scientific EffectDiffusion sintering: Sintering

Implementation Method 3

a low melting point in a state before sintering and the mounting temperature can therefore be reduced, and since diffusion sintering-type solders will irreversibly have a high melting point in a state after the diffusion sintering reaction

Methodology Applied
Scientific EffectIntermetallic compound formation: Chemical Bonding

Implementation Method 4

at least a portion of the resin (M) is a thermosetting resin (M1)

Methodology Applied
Scientific EffectThermosetting polymerization: Photopolymerisation

Data Source

PatentEP3415583B1Electrically conductive adhesive agent composition, and electrically conductive adhesive film and dicing-die bonding film using the same
Publication Date: 2024.06.05 FURUKAWA ELECTRIC CO LTD
  • EP3415583B1 patent drawingFigure 1~4
  • EP3415583B1 patent drawingFigure 5~6
  • EP3415583B1 patent drawing

AI summary

There is provided an electrically conductive adhesive agent composition which can be suitably used as an electrically conductive bonding material for bonding a semiconductor chip (particularly a power device) onto an element-supporting part of a lead frame or onto a circuit electrode part of an insulating substrate, for example, and which is capable of forming, between the semiconductor chip and the element-supporting part of a lead frame or the circuit electrode part of an insulating substrate, a bonding layer that particularly excels both in heat resistance after bonding and sintering and in mounting reliability while being lead-free, and an electrically conductive adhesive film and a dicing/die-bonding film using the same. The electrically conductive adhesive agent composition of the present invention comprises a metal particle (Q) and a prescribed organophosphorus compound (A), and the metal particle (Q) comprises a first metal particle (Q1) made of a single metal selected from the group of copper, nickel, aluminum and tin or an alloy comprising two or more metals selected from said group.