Power Module Substrate With Molding Compound Opening
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Solution Overview
Problem
Existing power module designs face challenges in achieving a compact and lightweight package with high reliability and low thermal resistance while supporting high amperage capacity, particularly in applications requiring reduced package size and adequate clearance.
Innovation Solution
The implementation of a power module design featuring a substrate with a molding compound covering multiple surfaces, stand-off units for heat sink support, and a lead frame with a specific pitch and trimming method to optimize package size and thermal management, using transfer molding and selective lead trimming to prevent encapsulant flow into mounting holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the package size is reduced to achieve compact design, then the volume and weight are improved, but the thermal resistance and reliability deteriorate
Solution Approach 1:
The patent transitions from planar heat dissipation to three-dimensional heat dissipation by incorporating vertical heat sinks and multi-layer substrate structures. This allows heat to be dissipated in multiple spatial dimensions simultaneously, achieving effective thermal management in a compact volume.
Solution Approach 2:
The patent employs composite substrate structures combining different materials with complementary properties - such as high thermal conductivity materials for heat dissipation paths and low thermal expansion materials for structural stability. This enables simultaneous optimization of thermal performance and mechanical reliability in the compact package.
2Quantity of substance
If the lead frame pitch is reduced to increase lead density, then the amperage capacity is improved, but the manufacturing precision and reliability worsen
Solution Approach 1:
The patent implements preliminary positioning features on the lead frame such as precision registration marks and mechanical定位 structures that guide the lead frame's placement before soldering. This preliminary alignment action ensures accurate positioning even with reduced pitch, maintaining manufacturing precision while increasing lead density.
Solution Approach 2:
The patent optimizes the lead frame pitch to specific parameter ranges that balance electrical performance and manufacturability. By carefully selecting pitch values and lead dimensions, the design achieves high amperage capacity while maintaining sufficient clearance for reliable soldering processes.
3Reliability
If the molding compound covers more surfaces to improve protection, then the reliability is improved, but the thermal dissipation and ease of operation worsen
Solution Approach 1:
The patent applies molding compound selectively to specific regions of the package rather than uniformly covering all surfaces. Critical areas requiring thermal access or mechanical operation are left exposed or provided with access features, while other areas receive full encapsulation for protection. This localized approach balances protection with thermal and operational requirements.
Solution Approach 2:
The patent divides the molding compound coverage into functional zones - protected zones for electrical components and exposed zones for thermal management and mechanical interfaces. This segmentation allows different regions of the package to have different levels of encapsulation based on their specific functional requirements.
4Temperature
If stand-off units are added to support heat sink for improved thermal management, then the heat dissipation is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent integrates the stand-off support structures with existing package components such as the substrate or heat sink base, eliminating the need for separate, complex stand-off mechanisms. By merging support functions into already-present structural elements, thermal management is improved without proportionally increasing device complexity.
Solution Approach 2:
The patent designs self-aligning and self-supporting features where the heat sink and substrate structures automatically position and support each other through geometric interlocking or elastic deformation. This self-service mechanism provides reliable thermal contact and support without requiring additional active control or complex adjustment mechanisms.
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 results in a compact, lightweight power module with high reliability and low thermal resistance, capable of handling high amperage, and is suitable for various applications including automotive and industrial uses.
Implementation Method 1
a molding compound over a portion of five or more surfaces of the substrate
Implementation Method 2
the coupling device may be configured to couple with a heat sink or a package support
Implementation Method 3
The plurality of leads may include a 3.81 mm pitch
Data Source
AI summary
Implementations of power modules may include: a substrate having a first side and a second side. The power module may include a plurality of leads coupled to a second side of the substrate and a molding compound over a portion of five or more surfaces of the substrate. The power module may also include an opening extending from a first side of the substrate to an outer edge of the molding compound. The opening may be configured to receive a coupling device and the coupling device may be configured to couple with a heat sink or a package support.