Adhesive Film Viscosity and Weight Loss for Semiconductor Reliability

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Solution Overview

Problem

Semiconductor packages face challenges with reflow cracks and void generation due to high temperature exposure during manufacturing, which affects the reliability and mechanical properties of multilayered semiconductor devices.

Innovation Solution

A semiconductor device with an adhesive film that satisfies specific viscosity and weight loss ratio criteria, ensuring heat resistance and impact resistance while preventing void formation, achieved by balancing flowability and internal pressure through a precise composition of thermoplastic resin, epoxy resin, phenol resin, and inorganic filler.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the adhesive layer is exposed to high temperature conditions for a long period of time during package manufacturing, then the curing process is completed, but voids are generated inside the adhesive layer or between the first chip and the adhesive layer

Engineering Contradiction:
Improvecuring completenessVSAvoidvoid generation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by carefully controlling the weight loss ratio (a) of the adhesive to be 0.1% or less through material composition optimization. This parameter control ensures that volatile components are minimized, preventing void formation while maintaining complete curing under high temperature conditions during package manufacturing.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the entire semiconductor package is heated to 200°C or higher during mounting, then the mounting process is completed, but moisture vaporizes and causes package cracking or reflow cracking

Engineering Contradiction:
Improvemounting processVSAvoidcrack resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies preliminary action by pre-controlling the moisture content and volatile component ratio (a ≤ 0.1%) in the adhesive before the mounting process. This preliminary control prevents explosive vaporization during subsequent high-temperature mounting, eliminating the root cause of reflow cracking while maintaining ease of manufacture.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent provides beforehand cushioning by optimizing the adhesive composition to have minimal volatile content (weight loss ratio a ≤ 0.1%). This creates a buffer against thermal stress during mounting, preventing crack initiation and propagation even when exposed to 200°C or higher temperatures.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Force

If the adhesive contains a large amount of moisture, then the adhesive force is sufficient, but moisture vaporization breaks the dicing die bonding film or delaminates the film causing reflow cracks

Engineering Contradiction:
Improveadhesive forceVSAvoidreflow crack prevention
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the weight loss ratio (a) to 0.1% or less through optimized material composition. This parameter adjustment maintains sufficient adhesive force while eliminating excess moisture that would cause vaporization and delamination during reflow processes.

Inventive Principle:
Principle #35Parameter changes

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 solution provides a stable multilayered semiconductor package structure with improved mechanical properties, preventing reflow cracks and voids, enhancing signal transmission efficiency and maintaining structural stability under high temperature conditions.

Implementation Method 1

a is a weight loss ratio (%) measured by thermogravimetric analysis (TGA) after exposure of the adhesive film at 125° C. for 1 hour

Methodology Applied
Scientific EffectThermal decomposition:

Implementation Method 2

moisture present in the semiconductor package explosively vaporizes

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

MV is a melt viscosity of the adhesive film measured at 125° C. by applying a shear rate of 5 rad/s

Methodology Applied
Scientific EffectViscosity:

Implementation Method 4

Moisture resistance of adhesive films for semiconductors

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 5

MV is a melt viscosity of the adhesive film measured at 125° C.

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentUS10920109B2Semiconductor device
Publication Date: 2021.02.16 LG CHEM LTD

AI summary

The present invention relates to a semiconductor device including: a first semiconductor element formed on an adherend; and an adhesive film for embedding the first semiconductor element, wherein the adhesive film satisfies a predetermined ratio between a melt viscosity and a weight loss ratio at a high temperature.