Lead Electrode Through-Hole Bonding for Lower Heat in Semiconductors
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Solution Overview
Problem
Conventional semiconductor devices face issues with unstable bonding between lead electrodes and semiconductor elements, leading to increased current density and reduced lifespan due to heat generation during high current conduction, and difficulty in inspecting bonding quality using ultrasonic flaw detection on curved surfaces.
Innovation Solution
A semiconductor device design featuring a metal part with one end bonded to the semiconductor element and inserted into a through hole of the lead electrode, increasing the bonding area and creating a planar bonding surface for easier inspection, which reduces current density and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lead electrode is bonded to a semiconductor element, then the bonding process is simple, but the bonding area is reduced and current density increases causing heat generation and shortened device life
Solution Approach 1:
The patent transitions from a conventional planar bonding interface to a three-dimensional configuration by inserting the metal part into the through hole of the lead electrode. This vertical insertion creates additional bonding surfaces along the inner wall of the through hole, effectively increasing the bonding area in the thickness direction while maintaining a compact footprint.
Solution Approach 2:
The metal part is nested within the through hole of the lead electrode, with the bonding material filling the space between them. This nested configuration maximizes the bonding interface area within the available volume, allowing the bonding material to contact both the metal part and the inner surface of the lead electrode simultaneously.
2Area of stationary object
If a cylindrical energized block is used to increase bonding area, then the bonding area increases, but the bonding surface becomes curved making ultrasonic flaw detection difficult
Solution Approach 1:
Instead of making the lead electrode surface curved to increase bonding area (as in the prior art), this patent inverts the approach by creating a planar bonding surface at the bottom of the through hole. The metal part is inserted vertically into the hole, and the bonding material creates a flat bonding interface that is perpendicular to the original curved surface, enabling effective ultrasonic inspection.
3Ease of manufacture
If the lead electrode shape varies or deforms during heating, then the bonding process is simple, but the distance between lead electrode and semiconductor element becomes unstable
Solution Approach 1:
The patent changes the geometric parameters of the bonding interface by creating a through hole with specific dimensions that accommodate the metal part. This structural modification provides mechanical constraints that prevent deformation and maintain stable positioning during the heating and bonding process, ensuring consistent bonding distance despite thermal effects.
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 enhances bonding quality inspection and reduces heat generation, thereby extending the lifespan of semiconductor devices and improving manufacturing efficiency by simplifying the inspection process.
Implementation Method 1
a bonding material to a principal surface of the semiconductor element
Implementation Method 2
When a lead electrode is bonded to a semiconductor element... while being heated
Implementation Method 3
The metal part connects the semiconductor element to the lead electrode
Implementation Method 4
a bonding area between the semiconductor element and the lead electrode can be increased. This reduces the current density between the lead electrode and the semiconductor elements
Implementation Method 5
One of the methods for inspecting the bonding quality of the second connection circuit and the surface electrode is ultrasonic flaw detection
Data Source
AI summary
An object is to provide a semiconductor device in which heat generated in a lead electrode when conducting a large current can be reduced and the bonding quality between the lead electrode and a semiconductor element can be inspected easily. A semiconductor device includes: a base portion; a semiconductor element mounted on the base portion; a metal part erect with respect to the semiconductor element and having one end bonded, with a bonding material, to a principal surface of the semiconductor element opposite to another principal surface of the semiconductor element mounted on the base portion; and a lead electrode connected to the semiconductor element through the metal part. The lead electrode includes a through hole extending in a thickness direction. The metal part connects the semiconductor element to the lead electrode, while inserted into the through hole of the lead electrode together with a part of the bonding material.