PCB Connection Terminal Thermal Management via Insulated Opening

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Solution Overview

Problem

In printed circuit boards, especially those used in hard disk drives, the high heat dissipation at connection terminals leads to premature solidification of solder, reducing connection reliability due to inadequate heat management.

Innovation Solution

A printed circuit board design featuring a support substrate with an insulating layer and a wiring trace, where an opening is formed around the connection terminal to partially or entirely surround the overlap region, keeping the insulating layer exposed and reducing heat dissipation, thereby preventing solder from solidifying prematurely.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the support substrate is made of conductive material with good thermal conductivity, then heat dissipation is improved, but the connection terminal temperature drops causing solder to solidify before spreading

Engineering Contradiction:

Improveheat dissipationVSAvoidconnection reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The support substrate is designed with non-uniform thermal conductivity: the region under the connection terminal has lower thermal conductivity (insulating layer present) to maintain temperature, while other regions have higher thermal conductivity for heat dissipation. This local differentiation resolves the contradiction between heat dissipation and connection temperature maintenance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The support substrate is segmented into different functional zones: a first region under the connection terminal with reduced thermal conductivity (due to insulating layer) and a second region with normal thermal conductivity. This segmentation allows simultaneous heat dissipation in the second region while maintaining temperature in the first region.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the insulating layer is removed in the overlap region to expose copper foil, then electrical connection is improved, but heat dissipation increases causing solder solidification

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidconnection terminal temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The insulating layer is selectively removed only in the opening region (not in the overlap region), creating local differentiation: the overlap region retains the insulating layer for thermal insulation, while the opening region provides electrical connection access. This resolves the contradiction between electrical connection and temperature maintenance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The connection terminal region is segmented into an overlap region (with insulating layer for thermal insulation) and an opening region (without insulating layer for electrical connection). This segmentation allows simultaneous achievement of thermal insulation and electrical connection.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the opening is made larger to surround the overlap region, then heat dissipation suppression is improved, but the structural strength is reduced

Engineering Contradiction:

Improveheat dissipation suppressionVSAvoidstructural strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The opening surrounds the overlap region but does not extend to the outer periphery of the support substrate, leaving a margin (not less than 5 μm) that provides structural strength. This partial action achieves sufficient heat dissipation suppression while maintaining structural integrity.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The distance between the opening and the outer periphery is optimized to a specific parameter range (not less than 5 μm) to balance thermal insulation performance and structural strength. This parameter optimization resolves the contradiction between heat dissipation suppression and structural strength.

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 design enhances connection reliability by maintaining the temperature of the connection terminal and reducing heat dissipation, ensuring the solder spreads evenly and solidifies correctly, improving bonding quality.

Implementation Method 1

the insulating layer that overlaps with the connection terminal remains without being removed, the temperature of the connection terminal is kept by the insulating layer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

an amount of heat spreading from a portion of the insulating layer that overlaps with the connection terminal to the entire support substrate is reduced

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9029712B2Printed circuit board and method of manufacturing the same

Publication Date: 2015.05.12 NITTO DENKO CORP

AI summary

Read wiring traces and write wiring traces are formed on an insulating layer that is formed on a support substrate. Connection terminals that are electrically connectable to external circuits are formed at parts of the read wiring traces and write wiring traces on the insulating layer, respectively. Openings are formed in the support substrate so as to partially or entirely surround overlap regions that overlap with the connection terminals and have the same plane shape as the connection terminals. Parts of the insulating layer are exposed in the openings.