Conductive Cap Layer for Semiconductor Package Charge Equalization

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Solution Overview

Problem

Semiconductor devices face challenges in packaging due to unequal potential distribution during the packaging process, which can lead to electrical overstress (EOS) and damage from electro-static discharge (ESD), especially as integration density increases and components become smaller, requiring more efficient charge equalization methods.

Innovation Solution

A conductive cap layer is disposed over integrated circuit dies and a molding material, providing a substantially equal potential across the packaged semiconductor device, comprising a material with lower resistance than the dies and molding material, to equalize charge and prevent damage from EOS and ESD.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If integration density is increased and components are made smaller, then more components can be integrated into a given area, but the risk of EOS and ESD damage increases due to unequal potential distribution

Engineering Contradiction:

Improveintegration densityVSAvoidrisk of EOS and ESD damage

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A conductive cap layer is disposed over the semiconductor devices to create an equipotential surface that equalizes charge distribution across all integrated circuit dies. This prevents potential differences that could lead to EOS and ESD damage, while allowing higher integration density through advanced packaging techniques like chip-on-wafer.

Inventive Principle:

Principle #12Equipotentiality

2Device complexity

If conventional packaging methods are used without a conductive cap layer, then the packaging process is simpler, but unequal potential distribution causes EOS and ESD damage to the semiconductor devices

Engineering Contradiction:

Improvepackaging process complexityVSAvoidprotection from EOS and ESD

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The conductive cap layer is formed as a continuous layer over the semiconductor devices to establish equipotential conditions. This simple structural addition equalizes charge distribution and protects against EOS and ESD without requiring complex packaging process changes.

Inventive Principle:

Principle #12Equipotentiality

Solution Approach 2:

The conductive cap layer acts as an intermediary element between the semiconductor devices and the external environment. It provides a controlled path for charge equalization and protects the sensitive integrated circuit dies from electrostatic discharge and electrical overstress.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a conductive cap layer is added to equalize charge and prevent EOS and ESD, then reliability is improved, but device complexity and manufacturing steps increase

Engineering Contradiction:

Improveprotection from EOS and ESDVSAvoidpackaging structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The conductive cap layer serves multiple functions simultaneously: it equalizes charge distribution across devices, provides ESD protection, establishes equipotential conditions, and can serve as an electrical connection layer. This multi-functionality reduces the need for additional separate protective structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The conductive cap layer changes the electrical parameters of the packaging structure by introducing a low-resistance path for charge equalization. This parameter change (adding conductivity) fundamentally improves protection against EOS and ESD without requiring complex structural modifications.

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 conductive cap layer effectively reduces the risk of EOS and ESD damage by ensuring equal potential across integrated circuit dies, enhancing packaging efficiency and yield, and providing a uniform surface for reduced cross-contamination and improved heat dissipation.

Implementation Method 1

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentUS9806062B2Methods of packaging semiconductor devices and packaged semiconductor devices

Publication Date: 2017.10.31 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Packaged semiconductor devices are disclosed. In some embodiments, a packaged semiconductor device includes a substrate and a plurality of integrated circuit dies coupled to the substrate. The device also includes a molding material disposed over the substrate between adjacent ones of the plurality of integrated circuit dies. A cap layer is disposed over the molding material and the plurality of integrated circuit dies, wherein the cap layer comprises an electrically conductive material that directly contacts the molding material and each of the plurality of integrated circuit dies.