Embedded Connection Pad Structure for Fine-Pitch Wire Bonding

Solution Overview

Problem

The challenge in the semiconductor package fabrication process is to achieve a fine pitch pattern for wire bonding while ensuring a wide enough bonding pad to reduce defects and accommodate the downsizing of electronic devices.

Innovation Solution

A circuit board design featuring an insulating layer with a first connection pad having different widths at its exposed and embedded portions, allowing for a wide bonding pad surface while maintaining a fine pitch pattern, and a method for fabricating this circuit board using an embedded trace substrate approach.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the bonding pad size is reduced to accommodate down-sizing of electronic devices, then the size of semiconductor packages becomes smaller, but the bonding defect rate increases

Engineering Contradiction:

Improvepackage sizeVSAvoidbonding defect rate

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The bonding pad structure implements local quality by having different widths at different depths: the upper surface width is larger to provide sufficient bonding area and reduce defect rate, while the lower embedded width is smaller to achieve fine pitch and compact package size. This non-uniform cross-sectional structure allows each region to serve its specific function optimally.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bonding pad extends into the third dimension by being embedded in the insulating layer with different widths at different depths. This vertical dimensionality allows the pad to have a larger surface area for reliable bonding while maintaining a smaller footprint for fine pitch, effectively resolving the contradiction between package size and bonding reliability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the bonding pad width is expanded to reduce bonding defect rate, then reliability improves, but the pitch between bond fingers increases

Engineering Contradiction:

Improvebonding defect rateVSAvoidpitch between bond fingers

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The bonding pad structure implements local quality by having different widths at different depths: the upper surface width is larger to provide sufficient bonding area and reduce defect rate, while the lower embedded width is smaller to achieve fine pitch and compact package size. This non-uniform cross-sectional structure allows each region to serve its specific function optimally.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bonding pad extends into the third dimension by being embedded in the insulating layer with different widths at different depths. This vertical dimensionality allows the pad to have a larger surface area for reliable bonding while maintaining a smaller footprint for fine pitch, effectively resolving the contradiction between package size and bonding reliability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS20250192020A1Circuit board and method of fabricating circuit board

Publication Date: 2025.06.12 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

A circuit board includes: an insulating layer having a first surface and a second surface opposing each other; and a first connection pad having a first portion embedded in the insulating layer and at least partly exposed from the insulating layer on the first surface and a second portion closer to the second surface than the first portion. A first width of the first portion in a direction parallel to the first surface is different from a second width of the second portion in the direction parallel to the first surface.