Double Adhesive Layer Circuit Connecting Material for Semiconductor Bonding

Solution Overview

Problem

Conventional underfill films in semiconductor chip mounting methods fail to provide good bonding with opposing electrodes due to solder wet spreading to solder-adhered electrode sides, preventing effective bonding.

Innovation Solution

A circuit connecting material with a double adhesive layer structure, where a first adhesive layer with a lower melting viscosity is used on the semiconductor chip side and a second adhesive layer with a higher melting viscosity is used on the circuit board side, allowing for controlled solder wetting and bonding at specific temperature and thickness conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional underfill film is used, then the mounting process can be simplified, but solder wet spreads to the solder-adhered electrode side and precludes good bonding with the opposing electrode

Engineering Contradiction:

Improvemounting process simplicityVSAvoidbonding quality with opposing electrode

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The underfill film is divided into two distinct adhesive layers: a first adhesive layer with lower melting viscosity and a second adhesive layer with higher melting viscosity. This segmentation allows each layer to perform different functions - the first layer prevents solder wet spread while the second layer enables proper bonding with the opposing electrode, thereby resolving the contradiction between ease of manufacture and bonding reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the underfill structure are given different properties - the first adhesive layer has lower melting viscosity to control solder wetting locally at the solder-adhered electrode interface, while the second adhesive layer has higher melting viscosity to ensure proper bonding at the opposing electrode interface. This local differentiation of material properties solves the bonding reliability issue while maintaining process simplicity.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If the first adhesive layer thickness is too thin, then solder wet spread is prevented, but bonding with the opposing electrode is insufficient

Engineering Contradiction:

Improvesolder wet spread preventionVSAvoidbonding strength with opposing electrode

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The underfill film is divided into two distinct adhesive layers: a first adhesive layer with lower melting viscosity and a second adhesive layer with higher melting viscosity. This segmentation allows each layer to perform different functions - the first layer prevents solder wet spread while the second layer enables proper bonding with the opposing electrode, thereby resolving the contradiction between ease of manufacture and bonding reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent specifies precise thickness parameters for the first adhesive layer (0.5×He1≦Hb1≦He1+0.75×Hs) and uses parameter changes in melting viscosity between the two layers to control solder wetting behavior. By carefully controlling the thickness and viscosity parameters, the invention prevents solder wet spread while ensuring adequate bonding strength with the opposing electrode.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single adhesive layer is used, then the structure is simple, but it cannot simultaneously prevent solder wet spread and ensure good bonding with opposing electrode

Engineering Contradiction:

Improveadhesive layer structureVSAvoidbonding performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The underfill film is divided into two distinct adhesive layers: a first adhesive layer with lower melting viscosity and a second adhesive layer with higher melting viscosity. This segmentation allows each layer to perform different functions - the first layer prevents solder wet spread while the second layer enables proper bonding with the opposing electrode, thereby resolving the contradiction between ease of manufacture and bonding reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure consisting of two different adhesive materials with distinct melting viscosity characteristics. The first adhesive material has lower melting viscosity to control solder wetting, while the second adhesive material has higher melting viscosity to ensure proper bonding. This composite approach achieves both solder protection and bonding reliability without excessive complexity.

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

This approach prevents solder wet spreading to the solder-adhered electrode side while ensuring good bonding with the opposing electrode, enhancing the bonding state and reducing void formation during thermo compression bonding.

Implementation Method 1

a first adhesive layer to be adhered to the semiconductor chip side, and a second adhesive layer having a lowest melting viscosity attainment temperature higher than that of the first adhesive layer

Methodology Applied

Scientific EffectViscosity control:

Implementation Method 2

a first adhesive layer to be adhered to the semiconductor chip side

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

a solder-adhered electrode is formed

Methodology Applied

Scientific EffectWetting: Wetting

Data Source

PatentUS9202755B2Circuit connecting material and semiconductor device manufacturing method using same

Publication Date: 2015.12.01 DEXERIALS CORP

AI summary

Provided are a circuit connecting material able to provide good bonding with an opposing electrode, and a semiconductor device manufacturing method using the same. The present invention uses a circuit connecting material, in which a first adhesive layer to be adhered to the semiconductor chip side, and a second adhesive layer having a lowest melting viscosity attainment temperature higher than that of the first adhesive layer are laminated. When the semiconductor chip on which the circuit connecting material is stuck is mounted on a circuit board, a thickness of the first adhesive layer is within a range satisfying formula (1), thereby providing good bonding with the opposing electrode.