Flexible Semiconductor Package with Notch Encapsulant

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Solution Overview

Problem

Conventional semiconductor package structures are stiff and unable to conform to curved or flexible surfaces, limiting their integration in devices with non-planar geometries.

Innovation Solution

A flexible semiconductor package structure is developed, featuring a conductive structure with semiconductor elements and an encapsulant that includes a notch portion, allowing the package to be bendable. The encapsulant is selected based on parameters that ensure a stress concentration factor greater than 1.2, enabling the package to withstand bending without rupture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional semiconductor package structures are used, then manufacturing and structural simplicity is maintained, but the package is stiff and unable to conform to curved or flexible surfaces

Engineering Contradiction:

Improveability to conform to curved surfacesVSAvoidstructural stiffness

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The encapsulant is divided into multiple sections by introducing notch portions that extend from the top surface toward the bottom surface. These notches segment the encapsulant structure, creating flexible regions that allow the package to bend and conform to curved surfaces while maintaining structural integrity in other areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The encapsulant is designed with controlled thickness and incorporates notch portions that create flexible regions. This allows the encapsulant to function as a flexible shell that can bend and adapt to curved surfaces, transforming the rigid package structure into a flexible one that maintains strength while achieving adaptability.

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If the encapsulant is made thinner to improve flexibility, then adaptability to curved surfaces improves, but rupture strength decreases

Engineering Contradiction:

ImproveflexibilityVSAvoidrupture strength

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The encapsulant is designed with non-uniform thickness and incorporates notch portions with specific geometric parameters (depth, width, curvature radius) that create localized flexible regions. The main body of the encapsulant maintains sufficient thickness for strength, while the notch portions provide flexibility, achieving local quality differentiation that balances both requirements.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The notch portions are designed with specific parameter ranges (depth between 0.1-0.5mm, width between 0.05-0.2mm, curvature radius between 0.02-0.1mm) that optimize the balance between flexibility and rupture strength. By controlling these geometric parameters, the encapsulant achieves adequate flexibility for bending while maintaining sufficient rupture strength to prevent failure.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If notch portions are added to the encapsulant to enable bending, then adaptability to curved surfaces improves, but stress concentration increases

Engineering Contradiction:

ImprovebendabilityVSAvoidstress concentration factor

Core Design Contradiction:

Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The notch portions are designed with curved surfaces and rounded corners rather than sharp angles. The curvature radius of the notches is specifically controlled (0.02-0.1mm) to smooth stress distribution. This spherical/curved geometry reduces stress concentration at the notch roots, allowing the encapsulant to bend without creating excessive stress that would lead to failure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 flexible semiconductor package structure can be bent along the notch portion without failing, accommodating curved or flexible device geometries while maintaining structural integrity.

Implementation Method 1

The encapsulant has a Young's modulus 'E' and a rupture strength 'Sr ', and L/(K×d)>E/Sr, wherein 'K' is a stress concentration factor with a value of greater than about 1.2

Methodology Applied

Scientific EffectStress concentration:

Implementation Method 2

The encapsulant has a Young's modulus 'E' and a rupture strength 'Sr'

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9929078B2Semiconductor package structure and method for manufacturing the same

Publication Date: 2018.03.27 ADVANCED SEMICON ENG INC

AI summary

A semiconductor package structure includes a conductive structure, at least two semiconductor elements and an encapsulant. The conductive structure has a first surface and a second surface opposite the first surface. The semiconductor elements are disposed on and electrically connected to the first surface of the conductive structure. The encapsulant covers the semiconductor elements and the first surface of the conductive structure. The encapsulant has a width ‘L’ and defines at least one notch portion. A minimum distance ‘d’ is between a bottom surface of the notch portion and the second surface of the conductive structure. The encapsulant has a Young's modulus ‘E’ and a rupture strength ‘Sr’, and L/(K×d)>E/Sr, wherein ‘K’ is a stress concentration factor with a value of greater than 1.2.