Wiring Substrate Pad Structure for Shear-Resistant Bump Bonding
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Solution Overview
Problem
Existing wiring substrates face challenges in achieving a strong and reliable connection between bumps and conductor pads due to stress exerted from external forces, leading to potential defects like peeling, especially when the connecting surface is a gentle curved surface.
Innovation Solution
A wiring substrate design featuring a conductor pad with a concave part and a convex part on its surface, where the bump is formed in a through hole penetrating the insulating layer, providing a wider connection area and improved mechanical coupling strength through an anchor effect, thereby enhancing the connection reliability and resistance to shear stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connecting surface is a gentle curved surface, then the manufacturing process is simple, but the connection strength and reliability deteriorate under external forces
Solution Approach 1:
The invention introduces a convex part with asymmetric geometry into the concave part of the conductor pad. The convex part has a width that is smaller than the width of the concave part, creating an asymmetric structure that provides both manufacturing simplicity and enhanced connection reliability through mechanical interlocking with the bump.
Solution Approach 2:
The invention uses a concave part with a curved surface to form the connecting surface. This curved geometry allows for simple manufacturing processes while the convex part within the concave part provides the necessary mechanical strength and reliability under external forces.
2Strength
If the connecting surface area is increased, then the connection strength improves, but the device complexity increases
Solution Approach 1:
The invention segments the connecting surface into a concave part and a convex part within it. This segmentation allows the connection area to be effectively increased through the concave geometry while maintaining relatively simple device complexity by using a single integrated structure rather than multiple separate components.
Solution Approach 2:
The invention transitions from a flat two-dimensional connecting surface to a three-dimensional structure with a concave part containing a convex part. This dimensional change increases the effective connection area and strength without proportionally increasing device complexity, as the additional area is achieved through vertical depth rather than horizontal expansion.
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 design ensures a strong and reliable connection between bumps and conductor pads, suppressing defects like peeling and improving mechanical coupling strength, ensuring high connection reliability even under external forces.
Implementation Method 1
providing a wider connection area and improved mechanical coupling strength through an anchor effect
Data Source
AI summary
A wiring substrate includes a conductor pad, an insulating layer formed on the conductor pad such that the insulating layer is covering the conductor pad and has a through hole, a bump formed on the conductor pad such that the bump is formed in the through hole penetrating through the insulating layer. The conductor pad is formed such that the conductor pad has a connecting surface connected to the bump, a concave part formed on the connecting surface of the conductor pad to the bump, and a convex part formed in the concave part.