Carbon-Based Redistribution Layers for Thinner Semiconductor Packages

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Solution Overview

Problem

Existing semiconductor device packages face challenges in achieving high electrical conductivity while maintaining a small form factor, particularly in stacked semiconductor dice configurations, due to the thickness and resistivity of traditional metal-based redistribution layers.

Innovation Solution

The use of carbon-based conductive elements, such as graphene, in redistribution layers with low electrical resistivity, allowing for thinner layers that maintain effective signal transmission and insulation, even at reduced vertical heights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional metal materials (aluminum or copper) are used for redistribution layers, then electrical conductivity can be achieved, but the layer thickness must be several micrometers which increases package height

Engineering Contradiction:

Improveelectrical conductivityVSAvoidpackage height

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent changes the material parameter from traditional metals (aluminum or copper) to carbon-based materials, which fundamentally alters the resistivity characteristic. This material substitution enables the redistribution layer to achieve effective electrical conductivity at dramatically reduced thicknesses, directly resolving the contradiction between maintaining conductivity and reducing package height

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs carbon-based composite materials (such as graphene, carbon nanotubes, or amorphous carbon) that combine exceptional electrical conductivity with atomic-scale thickness. These composite materials provide the dual benefit of high conductivity and minimal thickness, simultaneously addressing both the conductivity requirement and the height reduction goal

Inventive Principle:

Principle #40Composite materials

2Reliability

If metal materials are used with several micrometers thickness to compensate for resistivity, then effective electrical conductivity is achieved, but the form factor increases

Engineering Contradiction:

Improveelectrical conductivityVSAvoidform factor

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent fundamentally changes the material parameter from metals to carbon-based materials, transforming the resistivity-thickness relationship. Carbon-based materials exhibit such low resistivity that effective conductivity can be achieved at thicknesses orders of magnitude thinner than metal layers, thereby dramatically reducing the vertical volume occupied by the redistribution layer and overall package form factor

Inventive Principle:

Principle #35Parameter changes

3Length of stationary object

If the redistribution layer thickness is reduced to decrease package height, then form factor is improved, but electrical conductivity deteriorates with traditional metal materials

Engineering Contradiction:

Improvepackage heightVSAvoidelectrical conductivity

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The patent changes the material parameter to carbon-based materials which possess inherently lower resistivity than traditional metals. This parameter change inverts the conventional relationship where thicker layers are needed for conductivity; instead, the carbon-based material maintains superior conductivity even at ultrathin dimensions, enabling height reduction without sacrificing electrical performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the conventional metal-based conduction mechanism with a carbon-based conduction mechanism. Carbon materials such as graphene and carbon nanotubes provide electron transport pathways with dramatically lower scattering and resistance, enabling effective conductivity at thicknesses that would be electrically inadequate for metal materials

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables semiconductor device packages with significantly reduced height form factors, facilitating improved scaling in three-dimensional stacks and maintaining efficient electrical connections.

Implementation Method 1

carbon-based conductive elements, such as graphene, in redistribution layers with low electrical resistivity, allowing for thinner layers that maintain effective signal transmission

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20250279368A1Redistribution layers with carbon-based conductive elements, and related microelectronic device pacakages and methods of fabrication

Publication Date: 2025.09.04 LODESTAR LICENSING GROUP LLC

AI summary

Semiconductor device packages include a redistribution layer (RDL) with carbon-based conductive elements. The carbon-based material of the RDL may have low electrical resistivity and may be thin (eg., less than about 0.2 μm). Adjacent passivation material may also be thin (eg., less than about 0.2 μm). Methods for forming the semiconductor device packages include forming the carbon-based material (eg., at high temperatures (e.g., at least about 550° C.)) on an initial support wafer with a sacrificial substrate. Later or separately, components of a device region of the package may be formed and then joined to the initial support wafer before the sacrificial substrate is removed to leave the carbon-based material joined to the device region.