Power Module Leadframe Design for Warpage Reduction
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Solution Overview
Problem
Conventional power modules have high costs due to the need for specialized substrates and templates, and they suffer from warpage issues due to thermal expansion coefficient differences, affecting reliability and quality.
Innovation Solution
A power module design featuring a metallic plate with adhesive insulating layers and bonding wires, where the semiconductor device is mounted on the metallic plate, and the entire assembly is molded with resin, eliminating the need for substrate templates and reducing thermal expansion-related warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional substrates and templates are used for mounting semiconductor devices, then the power module can be manufactured, but the cost increases and warpage occurs due to thermal expansion coefficient differences
Solution Approach 1:
The patent removes the conventional substrate and template components from the power module structure. Instead of using separate substrates and templates for mounting semiconductor devices, the invention directly mounts devices onto the leadframe, eliminating the need for these additional components and thereby reducing manufacturing cost while avoiding warpage issues associated with thermal expansion coefficient mismatches.
Solution Approach 2:
The patent merges the functions of the substrate and template into the leadframe structure itself. The leadframe serves multiple functions: it provides mechanical support, electrical connections, and mounting surface for semiconductor devices, eliminating the need for separate substrate and template components.
2Device complexity
If conventional molding is performed without adhesive insulating layers, then manufacturing is simpler, but wiring reliability decreases
Solution Approach 1:
The patent introduces adhesive insulating layers as intermediary components between the leadframe and the molding resin. These layers serve dual functions: they provide electrical insulation to prevent short circuits and ensure reliable wiring connections, while also improving the bonding between the leadframe and molding resin. The addition of these thin layers does not significantly increase manufacturing complexity.
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 design reduces costs, stabilizes the substrate, and improves reliability by eliminating the need for substrate templates and minimizing warpage, while maintaining quality and efficiency.
Implementation Method 1
a first adhesive insulating layer and a second adhesive insulating layer respectively disposed on the metallic plate
Implementation Method 2
bonding-connecting between the semiconductor device and the metallic land for main electrode wiring via a first bonding wire; bonding-connecting between the semiconductor device and the metallic land for signal wiring via a second bonding wire
Implementation Method 3
molding the metallic plate, the first adhesive insulating layer, the second adhesive insulating layer, the metallic land for main electrode wiring, the metallic land for signal wiring, the semiconductor device, the first bonding wire, and the second bonding wire using a mold resin
Implementation Method 4
dispose a heat sink via an insulating layer on a back side surface of the leadframe in order to cool the semiconductor device
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A power module (20) includes: an insulating layer (12); a first metallic plate (3) disposed on the insulating layer (12); a first semiconductor chip (1) disposed on the first metallic plate (3); a first adhesive insulating layer (10) and a second adhesive insulating layer (11) disposed on the first metallic plate (3) ; a first metallic land (5) for main electrode wiring disposed on the first adhesive insulating layer (10); and a first metallic land (71, 72) for signal wiring disposed on the second adhesive insulating layer (11). There can be provided a power module having reduced cost, reduced warpage of the whole of a substrate, stabilized quality, and improved reliability; and a fabrication method for such a power module.