Stacked Semiconductor Terminal Arrangement for Bonding and Heat Dissipation

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Solution Overview

Problem

Current stacked semiconductor packages face challenges in simultaneously securing bonding strength and achieving excellent heat dissipation, as existing solutions either prioritize heat transfer alleviation or bonding strength, but not both effectively.

Innovation Solution

A stacked device with a specific terminal arrangement where terminals that bond and electrically connect semiconductors have an area ratio of 40% or higher on the surface, and terminals that bond but do not electrically connect have a lower area ratio, utilizing anisotropic conductive members with conductive paths extending in the stacking direction for direct bonding, and optionally incorporating an interposer for enhanced connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat transfer material is provided over the first semiconductor element and part of the first circuit board, then heat transfer from bottom package to top package is alleviated, but bonding strength between semiconductor elements is reduced

Engineering Contradiction:

Improveheat transferVSAvoidbonding strength

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The terminal surface is segmented into two functional zones: electrically connected terminals (for signal/power transmission) and non-electrically connected terminals (for heat dissipation and bonding). This segmentation allows the heat transfer material to be applied selectively to non-electrically connected terminals, preventing heat transfer between packages while maintaining bonding strength through the electrically connected terminals.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the terminal surface are assigned different functions: electrically connected terminals maintain direct metal-to-metal contact for strong bonding and signal transmission, while non-electrically connected terminals are covered with heat transfer material to dissipate heat without compromising electrical connection. This local differentiation resolves the contradiction between heat transfer alleviation and bonding strength.

Inventive Principle:

Principle #3Local quality

2Strength

If area ratio of electrically connected terminals is increased, then bonding strength is improved, but heat dissipation capability is reduced

Engineering Contradiction:

Improvebonding strengthVSAvoidheat dissipation

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The terminal surface is divided into electrically connected terminals (area ratio < 50%) for bonding strength and non-electrically connected terminals (area ratio ≥ 50%) for heat dissipation. This segmentation ensures that heat dissipation capability is maintained or improved while bonding strength is preserved through the electrically connected terminals.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The non-electrically connected terminals serve dual functions: they provide heat dissipation surface area and contribute to overall bonding strength through mechanical adhesion, even without electrical connection. This multi-functionality allows the terminal structure to simultaneously address both bonding strength and heat dissipation requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration secures bonding strength while ensuring excellent heat dissipation, reducing the risk of semiconductor malfunction due to heat generation and improving the reliability of the stacked device.

Implementation Method 1

utilizing anisotropic conductive members with conductive paths extending in the stacking direction for direct bonding

Methodology Applied

Scientific EffectAnisotropic conduction: Anisotropy

Implementation Method 2

This configuration secures bonding strength while ensuring excellent heat dissipation, reducing the risk of semiconductor malfunction due to heat generation

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11011499B2Stacked device, stacked structure, and method of manufacturing stacked device

Publication Date: 2021.05.18 FUJIFILM CORP

AI summary

A stacked device includes a stacked structure in which a plurality of semiconductors are electrically connected to each other, the semiconductor includes a surface on which a plurality of terminals are provided, the plurality of terminals include a terminal that bonds and electrically connects the semiconductors to each other and a terminal that bonds the semiconductors to each other and does not electrically connect the semiconductors to each other, an area ratio of the plurality of terminals on the surface of the semiconductor is 40% or higher, and an area ratio of the terminals that bond and electrically connect the semiconductors to each other among the plurality of terminals is lower than 50%.