Laser-Welded Metal Joint Structure to Prevent Surface Damage
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Solution Overview
Problem
Ultrasonic welding of metal members in semiconductor devices leads to surface damage due to rubbing, resulting in performance degradation.
Innovation Solution
A joint structure is created by overlapping and laser-welding metal members, forming a welded portion with an annular outer edge and curved linear marks, which suppresses surface damage by avoiding direct contact and friction during the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ultrasonic welding is used to join two metal members, then the metal members can be joined together, but surface damage occurs due to rubbing and wear
Solution Approach 1:
The patent replaces the mechanical ultrasonic vibration system with a laser-based thermal system. Instead of using ultrasonic vibrations to generate friction and heat for welding, the invention uses laser beams to directly heat and melt the metal members, eliminating the rubbing action that causes surface damage while achieving strong joints
Solution Approach 2:
The patent changes the fundamental welding parameter from mechanical vibration frequency to laser power and heating rate. By controlling laser irradiation conditions (power, duration, focal point) rather than mechanical vibration parameters, the welding process achieves strong bonding without the harmful friction-induced surface damage characteristic of ultrasonic welding
2Reliability
If direct joining of metal members is implemented, then lower resistance is achieved, but surface damage degrades device performance
Solution Approach 1:
The patent replaces mechanical contact-based joining with laser-based non-contact joining. The laser beam heats the metal members through radiation without physical contact, enabling direct joining for low resistance while eliminating the rubbing-induced surface damage that degrades device performance
Solution Approach 2:
The patent introduces laser radiation as an intermediary energy carrier between the power source and the metal members. This intermediary enables energy transfer and bonding without direct mechanical contact, achieving low-resistance joints while avoiding surface damage from friction
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 method effectively reduces surface damage and performance degradation by ensuring the metal members do not rub against each other, thereby enhancing the reliability and longevity of semiconductor devices.
Implementation Method 1
a laser beam is irradiated onto a first metal member 91 and a second metal member 92 that overlap with each other in a plan view, thereby the first metal member 91 and the second metal member 92 are joined to each other
Implementation Method 2
a welded portion 93 in which a part of the first metal member 91 and a part of the second metal member 92 are fused to each other
Implementation Method 3
two metal members are joined together by applying ultrasonic vibrations while pressing one of the metal members against the other
Implementation Method 4
two metal members rub against each other, and the metal members may wear as the result
Data Source
AI summary
A joint structure includes a first and a second metal member overlapping with each other as viewed in a first direction. The first metal member and the second metal member are joined together. The joint structure includes a welded portion at which the first metal member and the second metal member, overlapping with each other, are partly fused to each other. The welded portion has an outer circumferential edge and a plurality of linear marks. The outer circumferential edge is annular as viewed in the first direction. The plurality of linear marks each extend from an inside of the welded portion toward the outer circumferential edge as viewed in the first direction. Each of the plurality of linear marks is curved to bulge to one sense of an annular direction along the outer circumferential edge.