Wire Ball Surface Modification for Stronger Bonding
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Solution Overview
Problem
Existing wire bonding techniques for electronic devices face challenges when the wire material hardness is greater than the surface material hardness, leading to damage and insufficient bonding performance.
Innovation Solution
A process involving forming a modified surface on the wire ball by deforming it into an anvil with a higher hardness than the wire, increasing the surface area contact with the bond pad, and using ultrasonic bonding to enhance bonding strength and maintain sufficient bond pad material thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wire material hardness is greater than surface material hardness, then wire bonding can be performed, but damage to electronic components occurs
Solution Approach 1:
The patent applies preliminary action by forming a modified surface on the wire ball before bonding occurs. This modified surface, created through deformation or coating processes, is prepared in advance to reduce hardness mismatch and prevent damage during the bonding operation, thereby resolving the contradiction between achieving strong bonds and avoiding component damage.
2Strength
If conventional bonding is used with hard wire, then bonding can be achieved, but bond pad material thinning occurs
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of the wire ball through deformation or coating processes. This changes the hardness and surface area parameters of the bonding interface, allowing bonds to be formed without excessive pressure that would cause bond pad material thinning, thus resolving the contradiction between achieving bonding and preserving bond pad thickness.
3Strength
If wire ball surface area contact with bond pad is increased, then bonding strength improves, but loading forces must be distributed more uniformly
Solution Approach 1:
The patent applies preliminary action by pre-deforming the wire ball into an anvil to create a modified surface with increased area before bonding. This preliminary shaping ensures that when bonding occurs, the loading forces are already distributed more uniformly across the enlarged surface area, resolving the contradiction between achieving high bond strength and maintaining manufacturing precision in force distribution.
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 approach improves bond strength, reduces bond pad material thinning, and minimizes damage to electronic components by uniformly distributing loading forces and maintaining at least 20% of the original bond pad material thickness, thereby ensuring reliable electrical connectivity.
Implementation Method 1
operating on the first ball to modify a surface of the first ball to form a modified surface
Implementation Method 2
using ultrasonic bonding to enhance bonding strength
Data Source
AI summary
A process of forming an electronic device includes providing a wire comprising a first ball at an end thereof, operating on the first ball to modify a surface of the first ball to form a modified surface, moving the first ball to a first location on a die, and bonding the first ball along the modified surface to the first location of the die. In an embodiment, the process further includes moving a bonding tool including the wire away from the die while the wire remains bonded to the die.