Solder Ball Pad Locking Features Prevent Dielectric Delamination

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional solder ball pads in semiconductor devices experience delamination of the overlying dielectric layer due to thermal cycling and mechanical forces, leading to cracking and potential device failure.

Innovation Solution

The solder ball pads are designed with features such as outwardly extending protrusions and through-holes to enhance adhesion and prevent delamination, including a tapered end, central pad portion, and recessed portions to lock the dielectric layer in place, thereby inhibiting edge-induced and surface-induced delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional flat solder ball pad design is used, then the manufacturing process is simple, but the dielectric layer delaminates under thermal cycling and mechanical forces

Engineering Contradiction:

Improveadhesion of dielectric layerVSAvoidsolder ball pad structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The solder ball pad is segmented into multiple functional regions including a central pad portion, recessed portions, and outwardly extending protrusions. This segmentation creates a complex geometry that enhances mechanical interlocking with the dielectric layer, preventing delamination while maintaining manufacturing feasibility through standard photolithography and plating processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the solder ball pad are designed with distinct geometric properties: the central pad portion provides a large bonding area, the recessed portions create mechanical interlocking features, and the outwardly extending protrusions enhance edge adhesion. This local differentiation of structural qualities optimizes adhesion in specific areas where delamination is most likely to occur.

Inventive Principle:

Principle #3Local quality

2Reliability

If the solder ball pad structure is enhanced with protrusions and through-holes to prevent delamination, then adhesion improves, but manufacturing complexity increases

Engineering Contradiction:

Improveresistance to delaminationVSAvoidsolder ball pad fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The complex geometric features of the solder ball pad, including recessed portions and outwardly extending protrusions, are formed during the metallization layer fabrication process before dielectric layer deposition. This preliminary formation of adhesion-enhancing structures ensures that the dielectric layer is deposited onto a pre-optimized surface geometry, eliminating the need for additional post-processing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The solder ball pad design utilizes controlled variations in geometric parameters such as protrusion height, recessed portion depth, and pad area distribution. These parameter changes are achieved through standard photolithography patterning and electroplating thickness control, allowing complex geometries to be manufactured using existing process capabilities without requiring new equipment or techniques.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9548280B2Solder pad for semiconductor device package

Publication Date: 2017.01.17 NXP USA INC

AI summary

A solder ball pad for mounting a solder ball of a semiconductor device for preventing delamination of an overlying dielectric layer, and particularly devices and methods providing improved solder ball pad structures in a device such as a semiconductor device package.