Nested Pad Structure for Circuit Carrier Layout Density

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Solution Overview

Problem

The increasing density of contacts in electronic products requires narrower line widths and closer spacing of pads, leading to space limitations that degrade electrical performance due to signal reflection, crosstalk, and coupling, while traditional pad structures lack flexibility in layout design.

Innovation Solution

A pad structure comprising an inner pad, a conductive via, and an outer pad, where the outer diameter of the outer pad is greater than the inner pad, allowing for reduced inner pad diameter to enhance layout flexibility and electrical performance, utilizing laser ablation for precise positioning and potentially incorporating multiple conductive vias and varied inner pad shapes to optimize layout density and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the outer diameter of the pad is reduced to increase contact density, then the layout density is improved, but the electrical performance degrades due to signal reflection, crosstalk and coupling

Engineering Contradiction:

Improvelayout densityVSAvoidelectrical performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pad structure is segmented into two distinct parts: an inner pad with a first outer diameter and an outer pad with a second outer diameter. The inner pad is positioned within the outer pad, creating a nested configuration. This segmentation allows the inner pad to have a smaller diameter for improved layout density while the outer pad provides a larger bonding area for maintaining electrical performance and reducing signal interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the pad structure are assigned different functions and dimensions. The inner pad region is optimized for layout density with a smaller diameter, while the outer pad region is optimized for electrical performance with a larger diameter. This local differentiation allows each region to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #3Local quality

2Productivity

If the line width and line interval are reduced to increase contact density, then the layout density is improved, but the electrical performance degrades due to signal reflection, crosstalk and coupling

Engineering Contradiction:

Improvecontact densityVSAvoidelectrical performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pad structure transitions from a single-dimensional concern (pad diameter) to a two-dimensional nested configuration (inner pad within outer pad). This dimensional change allows the inner pad to be smaller for density while the outer pad compensates for electrical performance, effectively resolving the contradiction by operating in an expanded design space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the outer diameter of the pad is reduced to increase contact density, then the layout flexibility is improved, but the bonding area is reduced

Engineering Contradiction:

Improvelayout flexibilityVSAvoidbonding area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The bonding function is segmented between the inner pad and outer pad. The inner pad provides the connection point for trace lines with improved layout flexibility, while the outer pad provides the enlarged bonding area for reliable electrical connection. This segmentation allows both layout flexibility and bonding area to be optimized simultaneously.

Inventive Principle:

Principle #1Segmentation

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 increases layout density and electrical performance by reducing the inner pad diameter, allowing for more flexible layout and improved mechanical strength, while maintaining effective bonding and reducing signal interference.

Implementation Method 1

The conductive via connects the inner pad

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

utilizing laser ablation for precise positioning

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS8736079B2Pad structure, circuit carrier and integrated circuit chip

Publication Date: 2014.05.27 VIA TECH INC

AI summary

A pad structure is suitable for a circuit carrier or an integrated circuit chip. The pad structure includes an inner pad, a conductive via and an outer pad. The conductive via connects the inner pad. The outer pad connects the conductive via and further connects a conductive ball or a conductive bump. The outer diameter of the outer pad is greater than the outer diameter of the inner pad.