Conductive Block with Convex Portion for Semiconductor Thermal Stress Relief
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Solution Overview
Problem
The bonding reliability between the front surface electrode of a semiconductor element and a plate-shaped lead electrode is deteriorated due to large stress caused by differences in thermal expansion coefficients, leading to reliability issues in high-power semiconductor devices.
Innovation Solution
A semiconductor device configuration that includes a conductive block with a convex portion bonded to the insulating substrate, which moderates temperature changes and alleviates stress at bonding interfaces, using a conductive plate with a higher thermal expansion coefficient than the semiconductor element but lower than the conductive block to enhance heat dissipation and reduce distortion, and employing a sintered copper bonding layer for reliable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a plate-shaped lead electrode is used to bond the front surface electrode of the semiconductor element, then the wiring pattern area on the insulating substrate can be reduced, but large stress is applied due to difference in thermal expansion coefficient, deteriorating bonding reliability
Solution Approach 1:
A plate-shaped conductive block is introduced as an intermediary component between the semiconductor element and the lead electrode. This conductive block serves as a stress-absorbing intermediate layer that reduces the thermal expansion stress transmitted to the bonding interface, thereby improving bonding reliability while maintaining compact wiring pattern design
Solution Approach 2:
The invention changes the physical parameters of the bonding structure by using a conductive block with specific thermal expansion properties that differ from both the semiconductor element and the lead electrode. This parameter optimization allows the intermediate block to absorb thermal stress, preventing bonding deterioration
2Power
If current density of the semiconductor device is increased to handle higher power, then power conversion capability is improved, but heat generation increases, causing bonding layer deterioration due to thermal expansion and contraction
Solution Approach 1:
The plate-shaped conductive block acts as a mediator between the heat-generating semiconductor element and the external environment. It provides a thermal buffer that reduces the impact of thermal expansion and contraction on the bonding layers, enabling high current density operation without bonding deterioration
Solution Approach 2:
The conductive block is positioned beforehand to cushion against thermal stresses before they can damage the bonding layers. This preventive structure absorbs thermal expansion forces during high-power operation, protecting the bonding interfaces from deterioration
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 configuration improves the reliability of power semiconductor devices by reducing thermal stress and enhancing heat dissipation, resulting in a more reliable bonding interface and increased durability.
Implementation Method 1
a plate-shaped conductive block electrically connected to a front surface electrode of the semiconductor element through a conductive plate
Implementation Method 2
there is a problem in that, the region of the wiring pattern on the insulating substrate is not sufficient... large stress is applied due to a difference in thermal expansion coefficient
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(i)
AI summary
Provided is a semiconductor device with high reliability. In order to solve the above problems, according to the present invention, the semiconductor device includes a heat dissipating substrate, an insulating substrate arranged on the heat dissipating substrate and having a wiring layer, a plurality of semiconductor elements arranged on the insulating substrate, a conductive block electrically connected to a front surface electrode of the semiconductor element, and a terminal electrode, in which the conductive block has a convex portion, and the convex portion is bonded to the insulating substrate.