Circuit Board Solder Resist Layer Design for Void Suppression

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Solution Overview

Problem

The existing surface mount technology faces challenges in securing physical and electrical reliability due to mold void phenomena during the molding process, especially under surface-mounted components, which can lead to packaging defects and interference effects.

Innovation Solution

A circuit board design that includes an insulating layer with distinct areas for component mounting and connection pads, along with a solder resist layer that extends from adjacent areas to the mounting area, creating a thicker first portion over the mounting area and a thinner second portion in adjacent areas, thereby supporting the electronic component and improving cleaning power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solder resist layer completely covers the mounting area, then electrical insulation is improved, but cleaning power under the component deteriorates

Engineering Contradiction:

Improveelectrical insulationVSAvoidflux residue accumulation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The solder resist layer is designed with different thicknesses in different regions: a first thickness in the mounting area and a second thickness in adjacent areas, creating local quality variations that simultaneously provide insulation and enable cleaning access

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solder resist layer is segmented into multiple thickness regions, with the first portion having a first thickness and the second portion having a second thickness, allowing different functional requirements to be met in different zones

Inventive Principle:

Principle #1Segmentation

2Volume of moving object

If the circuit board and mounted component are placed close together, then device size is reduced, but mold void defects increase

Engineering Contradiction:

Improvepackage sizeVSAvoidmold void defects

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The solder resist layer exhibits local quality variations with different thicknesses in different areas, providing enhanced separation and cleaning access in the mounting area while maintaining compact overall dimensions

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If the solder resist layer is made uniformly thick, then manufacturing precision is improved, but cleaning power under component deteriorates

Engineering Contradiction:

Improvelayer thickness consistencyVSAvoidflux residue

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The solder resist layer is deliberately designed with non-uniform thickness, having a first thickness in the mounting area and a second thickness in adjacent areas, where each region's thickness is optimized for its specific functional requirements

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250126717A1Circuit board and electronic component package

Publication Date: 2025.04.17 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

An embodiment of the present disclosure provides a circuit board including: an insulating layer including a first area on one surface on which an electronic component is mounted and a second area adjacent to the first area; a connection pad disposed in the first area; and a solder resist layer covering the one surface of the insulating layer and being opened to expose the connection pad. At least a portion of the solder resist layer extends from the second area to the first area, and a portion of the insulating layer is exposed from the solder resist layer in the first area.