Semiconductor Device Protruding Metal Layer Thermal Stress
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Solution Overview
Problem
The semiconductor device faces increased thermal stress due to the difference in linear expansion coefficients between the insulating and metal layers, which can lead to damage as the substrate size increases, necessitating a reduction in substrate size to mitigate this stress while maintaining electrical connectivity.
Innovation Solution
The semiconductor device incorporates a configuration with a first metal layer having a main portion and a protruding portion on the insulating substrate, where the semiconductor element is placed on the main portion and the external connection terminal is bonded to the protruding portion, allowing for a smaller insulating layer area and maintaining insulation through a longer creepage distance, thereby reducing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating substrate size is increased to accommodate both semiconductor element and external connection terminal on the same metal layer, then electrical connectivity is maintained, but thermal stress increases due to larger area
Solution Approach 1:
The metal layer extends in the vertical dimension by creating a protruding portion that rises from the insulating layer surface. This allows the external connection terminal to bond to the metal layer at a location that projects beyond the insulating layer boundary, effectively utilizing three-dimensional space rather than being constrained to the two-dimensional plane of the insulating substrate. This dimensional transition enables electrical connectivity without requiring increased insulating substrate area, thereby reducing thermal stress.
2Stress or pressure
If the insulating substrate size is reduced to decrease thermal stress, then thermal stress is reduced, but the area available for metal layer becomes insufficient for both semiconductor element and external connection terminal
Solution Approach 1:
By forming the metal layer with a protruding portion that extends vertically from the insulating layer, the effective bonding area for the external connection terminal is increased without increasing the footprint area of the insulating substrate. This allows sufficient metal layer area for both semiconductor element mounting and external terminal bonding while maintaining a compact insulating substrate size, thus reducing thermal stress.
3Reliability
If the metal layer area is increased to accommodate both semiconductor element and external connection terminal, then electrical connectivity is ensured, but the insulating layer area must also increase leading to higher thermal stress
Solution Approach 1:
The metal layer is configured with a protruding portion that extends beyond the insulating layer boundary in the vertical direction. This allows the external connection terminal to bond to the metal layer at a location that does not require additional insulating layer area. Consequently, electrical connectivity is ensured while the insulating layer area remains minimized, reducing thermal stress on the insulating substrate.
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 effectively reduces thermal stress on the insulating substrate while maintaining electrical connectivity and improving heat dissipation performance, allowing for more flexible semiconductor element arrangement and reduced risk of substrate damage.
Implementation Method 1
an insulating layer 34, an inner metal layer 56 and an outer metal layer 58. The inner metal layer 56 and the outer metal layer 58 are electrically insulated from each other by the insulating layer 34
Implementation Method 2
since the linear expansion coefficients of the insulating layer and the metal layer are different, thermal stress tends to occur with a temperature change
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A semiconductor device includes: an insulating substrate including an insulating layer (34; 54) of which a first metal layer and a second metal layer are provided on both surfaces; a semiconductor element provided on the first metal layer; and an external connection terminal (14; 16) bonded to the first metal layer, the external connection terminal being electrically insulated from the second metal layer, wherein: the first metal layer includes a main portion (36a; 56a) being in contact with the insulating layer, the semiconductor element being provided in the main portion, and a protruding portion (36b; 56b) protruding from the main portion, the external connection terminal being bonded to the protruding portion; and at least a part of the protruding portion is provided to protrude from an outer peripheral edge (34e; 54e) of the insulating layer in a plan view of the insulating substrate.