Bumped Solder Pad Structure for Adhesion Strength
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Solution Overview
Problem
Conventional solder pads face challenges in achieving strong adhesion with solder balls due to limited contact surface area, which affects electrical, mechanical, and thermal connections, and can be compromised by oxidation, leading to reduced reliability and performance.
Innovation Solution
The introduction of bumps on the solder pad, made from conductive materials like nickel-gold alloy, increases the contact surface area and provides a protective surface finish to prevent oxidation, enhancing adhesion and connectivity between the solder pad and solder ball.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional solder pad structure is used, then manufacturing process is simple, but adhesion strength between solder ball and solder pad is insufficient
Solution Approach 1:
The solder pad surface is segmented into multiple protruding bumps instead of a flat surface. Each bump acts as an independent adhesion point, collectively providing significantly stronger bonding area and mechanical interlocking with the solder ball, thereby resolving the adhesion strength issue while maintaining reasonable structural complexity.
Solution Approach 2:
The solder pad structure transitions from a two-dimensional flat surface to a three-dimensional protruding bump structure. This dimensional change increases the effective surface area and provides mechanical interlocking capability, significantly enhancing adhesion strength without excessive complexity increase.
2Area of stationary object
If conventional solder pad structure is used, then manufacturing process is simple, but contact surface area is limited
Solution Approach 1:
The contact surface is divided into multiple discrete bumps rather than a continuous flat surface. This segmentation multiplies the effective contact area through the cumulative surface area of all bumps, providing better electrical, mechanical, and thermal contact while keeping the manufacturing process relatively simple.
Solution Approach 2:
By transitioning from a 2D flat surface to a 3D bump structure, the contact surface area is significantly increased. The protruding nature of bumps adds vertical dimension to the contact interface, enabling greater surface area within the same planar footprint.
3Reliability
If conventional solder pad structure is used, then structure is simple, but protection against oxidation is insufficient
Solution Approach 1:
The bumps provide localized protection zones where solder material accumulates and forms protective joints. These localized structures create micro-environments that are more resistant to oxidation by establishing stronger metallurgical bonds faster, improving reliability without requiring complex overall structural changes.
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
The bumps significantly improve the adhesion strength and connectivity by increasing the contact surface area and protecting the solder pad from oxidation, thereby enhancing the reliability and performance of electrical, mechanical, and thermal connections.
Implementation Method 1
The introduction of bumps on the solder pad, made from conductive materials like nickel-gold alloy, increases the contact surface area
Implementation Method 2
provides a protective surface finish to prevent oxidation, enhancing adhesion and connectivity between the solder pad and solder ball
Implementation Method 3
made from conductive materials like nickel-gold alloy, increases the contact surface area and provides a protective surface finish
Implementation Method 4
enhancing the reliability and performance of electrical, mechanical, and thermal connections
Data Source
AI summary
A bumped solder pad and methods for adding bumps to a solder pad are provided. A substrate is provided having metal layer formed thereon and a solder pad formed from a portion of the metal layer. A surface treatment is applied to the solder pad. The surface treatment is patterned. The surface treatment is etched to produce at least one bump on the solder pad.