Power Module Resin Flow Guide Reduces Substrate Displacement
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Solution Overview
Problem
Existing power modules face issues with displacement defects in the heat dissipation substrate due to the impact force of resin during packaging, which affects electrical safety and stability.
Innovation Solution
The power module design includes a packaging body with a recessed first step portion and a mold cavity wall step to reduce the impact force of resin on the heat dissipation substrate during transfer molding, ensuring smooth resin flow and minimizing displacement defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If resin is injected during transfer molding to package power chips and control chips, then the power module achieves high integration level and convenient use, but the heat dissipation substrate experiences displacement defects due to resin impact force
Solution Approach 1:
The patent applies preliminary action by designing a flow guide portion and cavity wall step in advance before resin injection. These structural features are pre-configured in the mold cavity to guide resin flow and reduce impact force on the heat dissipation substrate, preventing displacement defects before they occur during the packaging process
Solution Approach 2:
The flow guide portion acts as an intermediary structure between the resin injection point and the heat dissipation substrate. It mediates the resin flow by providing a controlled path that reduces the direct impact force on the heat dissipation substrate, allowing successful packaging while preventing displacement defects
2Reliability
If resin injection is performed to achieve complete packaging of power chips, then packaging completeness is improved, but impact force on heat dissipation substrate increases causing displacement and potential electrical safety issues
Solution Approach 1:
The patent converts the harmful impact force of resin into a beneficial controlled flow pattern. By designing the flow guide portion and cavity wall step, the resin's kinetic energy is redirected to follow a controlled path that ensures complete packaging while minimizing harmful impact on the heat dissipation substrate, effectively transforming the harmful effect into a beneficial controlled process
3Manufacturing precision
If the resin injection opening is positioned to ensure complete packaging, then packaging quality is improved, but the distance from injection opening to heat dissipation substrate is reduced increasing impact force
Solution Approach 1:
The patent addresses the distance and impact force issue by introducing a spatial dimension solution through the flow guide portion and cavity wall step. Instead of simply increasing the linear distance from the injection opening, these structures create a three-dimensional flow path that extends the resin flow trajectory, allowing complete packaging while reducing impact force through extended flow path in multiple dimensions
Data Source
Figure 1A~2A
Figure 2B~2D
Figure 2E~4
AI summary
A power module, comprising: a packaging body; a power chip, a control chip, and a heat dissipation substrate which are arranged in the packaging body; and a power pin and a control pin respectively led out from a first side surface and a second side surface of the packaging body. The power chip is arranged on the heat dissipation substrate. The bottom surface of the heat dissipation substrate is flush with the bottom surface of the packaging body and is exposed outside the packaging body. The packaging body comprises a resin injection portion and a first step portion. The first step portion is located on a side of the part of the power pin extending out of the packaging body, wherein the side is close to the bottom surface of the packaging body. In the width direction of the packaging body, the side surface of the first step portion is closer to the heat dissipation substrate than the first side surface; and in the thickness direction of the packaging body, the step surface of the first step portion is closer, than the bottom surface of the packaging body, to the part of the power pin extending out of the packaging body, and the distance from the step surface of the first step portion to the bottom surface of the packaging body is less than the distance from the resin injection portion to the bottom surface of the packaging body.