Low CTE Dielectric Filled Plated Through-Hole Structure

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Solution Overview

Problem

Existing plated through-hole structures face challenges with dielectric materials that fail to adhere sufficiently to metal substrates, leading to issues with drilling and plating, which can result in short circuits and voids.

Innovation Solution

A method involving filling a through-hole in a substrate with a composition having a coefficient of thermal expansion (CTE) of less than 50 ppm/°C, followed by forming a second through-hole and plating the interior surface to create a reliable plated through-hole structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dielectric materials are used to fill through-holes in metal substrates, then the through-holes can be filled and plated, but the dielectric material fails to adhere sufficiently to the metal substrate, leading to drilling issues, plating defects, short circuits, and voids

Engineering Contradiction:

Improveadhesion of dielectric material to metal substrateVSAvoidshort circuits and voids

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by selecting a dielectric material with a specific coefficient of thermal expansion (CTE) parameter - specifically, a CTE of less than 50 ppm/°C. This parameter change resolves the adhesion problem by matching the thermal expansion characteristics of the dielectric material to those of the metal substrate, preventing delamination and ensuring reliable bonding during thermal processing and operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by using a dielectric material that combines low CTE properties with appropriate mechanical and electrical characteristics. This composite approach allows the dielectric to simultaneously achieve strong adhesion to metal substrates, prevent void formation, and maintain electrical insulation properties, thereby resolving multiple conflicting requirements.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the dielectric material has poor adhesion to the metal substrate, then the plating process can proceed, but drilling through the dielectric material becomes difficult and plating defects occur

Engineering Contradiction:

Improvedrilling and plating processabilityVSAvoidplating quality and void prevention

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

By changing the CTE parameter of the dielectric material to be less than 50 ppm/°C, the material achieves compatible thermal expansion behavior with metal substrates. This parameter optimization ensures that the dielectric material maintains dimensional stability during drilling and plating operations, enabling easy manufacturing while producing high-quality results without voids or delamination.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If existing dielectric materials are used, then the through-hole structure can be formed, but the electrical connection reliability is compromised due to short circuits and voids

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidthrough-hole structure integrity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent resolves electrical connection reliability issues by changing the thermal expansion parameter of the dielectric material. The low CTE (<50 ppm/°C) ensures that the dielectric material maintains stable dimensional characteristics during thermal cycling and manufacturing, preventing void formation and short circuits, thereby achieving reliable electrical connections through properly formed plated through-holes.

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

This approach ensures good adhesion of the dielectric material to the metal substrate, prevents voids, and provides a reliable electrical connection, overcoming the limitations of existing technologies.

Implementation Method 1

filling a first through-hole in a substrate with a composition having a coefficient of thermal expansion of less than 50 ppm/°C

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

plating the interior surface of the second through-hole to provide the plated through-hole structure

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS20250113446A1Plated through-hole structures and method for the manufacture thereof

Publication Date: 2025.04.03 ROGERS CORP

AI summary

A method for forming a plated through-hole structure includes filling a first through-hole in a substrate with a composition having a coefficient of thermal expansion of less than 50 ppm/° C. The composition is disposed on the interior surface of the first through-hole from the first opening to the second opening. The method further includes forming a second through-hole in the first through-hole filled with the composition. The second through-hole has a diameter less than a diameter of the first through-hole. The method further includes plating the interior surface of the second through-hole to provide the plated through-hole structure. The method can provide plated through-hole structures exhibiting good adhesion to metal and providing a reliable electrical connection.