Wiring Board Dummy Pattern Moisture Escape

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Solution Overview

Problem

The challenge in semiconductor apparatuses is the expansion of moisture due to heat, leading to defects such as shape changes and disconnection of wiring, particularly in thin wiring boards, which hinders the miniaturization of electronics and increases production costs.

Innovation Solution

A wiring board with a dummy wiring pattern in the semiconductor-chip mount area, where all wiring lines have free ends, preventing the formation of closed areas and allowing moisture to escape, thus avoiding accumulation and expansion issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the wiring board is made thinner to enable miniaturization of electronics devices, then the size of the semiconductor apparatus is reduced, but moisture accumulation and expansion defects increase

Engineering Contradiction:

Improvesize of semiconductor apparatusVSAvoiddefect rate due to moisture expansion

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The wiring board is divided into a moisture release area with through-holes that segment the board structure, allowing moisture to escape and preventing accumulation that would cause expansion defects in thin wiring boards

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Through-holes act as intermediary structures that provide moisture escape paths, mediating between the conflicting requirements of thin board design and moisture management to prevent reliability issues

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If vents are added to the wiring board to release moisture, then moisture expansion defects are reduced, but the structure becomes more complex and production cost increases

Engineering Contradiction:

Improvedefect rate due to moisture expansionVSAvoidstructure complexity of wiring board

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The through-holes serve multiple functions: they provide moisture escape paths, act as electrical connection points via plating, and can be integrated with existing wiring patterns, reducing the need for separate moisture management structures

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The moisture release function is merged with the electrical wiring function by forming conductive plugs in the through-holes, combining two features into a single integrated structure that reduces overall complexity

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If more external terminals are added to support high-speed and highly-functional signal processing, then the functionality of the semiconductor apparatus is improved, but the area occupied increases

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidarea of wiring board

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

External terminals are arranged in a two-dimensional grid pattern on the bottom surface of the wiring board, utilizing the vertical dimension and bottom surface area to increase terminal count without proportionally increasing the overall board footprint

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS7876572B2Wiring board and semiconductor apparatus

Publication Date: 2011.01.25 SHARP KK

AI summary

A wiring board of the present invention includes a dummy wiring in a semiconductor-chip mount area on which a semiconductor chip is to be mounted. The dummy wiring is arranged in a manner such that all wiring-lines included in the dummy wiring each have a free end within the semiconductor-chip mount area. This prevents a defect due to vaporization and expansion of moisture inside a semiconductor apparatus, with a simple structure and without raising costs.