Molded Heat Dissipation Plate for Thermal and Insulation Separation
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Solution Overview
Problem
The existing methods for manufacturing power modules, such as those used in hybrid electric vehicles and industrial applications, face challenges in reducing production costs while maintaining performance, particularly in achieving efficient thermal conduction and electrical insulation without compromising design considerations.
Innovation Solution
The method involves using a molded plate formed of a first mold compound interposed between the semiconductor die and the molding chamber's interior surface, surrounded by a second mold compound, allowing for a reduced thickness of mold material and enabling the use of materials with different thermal conductivity, dielectric constant, and cost characteristics, thus eliminating tradeoffs between thermally active and surrounding package body components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single mold compound is used for the entire package body, then manufacturing is simpler and cost is lower, but thermal conduction performance is compromised because the same material must balance both thermal and electrical requirements
Solution Approach 1:
The package body is segmented into two distinct regions: a first mold compound region (312) providing thermal conduction path, and a second mold compound region (314) providing electrical insulation. This segmentation allows each region to be optimized for its specific function rather than using a single compromise material throughout the entire package body.
Solution Approach 2:
Different regions of the package body are assigned different material properties: the first mold compound (region 312) is selected with high thermal conductivity for the thermal conduction path, while the second mold compound (region 314) is selected with high dielectric strength for electrical insulation. Each local region has quality optimized for its specific functional requirement.
2Temperature
If mold material thickness is reduced to improve thermal conduction, then thermal performance improves, but electrical insulation may be compromised
Solution Approach 1:
The insulation function is segmented from the thermal conduction path by creating a distinct second mold compound region (314) that is electrically connected to the first mold compound region (312) through conductive elements (306). This allows the thermal path to be thin while the insulation path maintains sufficient thickness and dielectric strength.
Solution Approach 2:
Conductive elements (306) act as intermediaries that bridge the first and second mold compound regions, allowing the thin thermal conduction path to be electrically isolated from surrounding structures while maintaining thermal contact between the semiconductor die and heat sink.
3Reliability
If different materials are used for thermal and surrounding package body components, then performance is optimized, but manufacturing complexity and cost increase
Solution Approach 1:
The molding process merges multiple functions into a single operation: the first and second mold compounds are molded simultaneously or sequentially in one process step, forming both the thermal conduction path and the electrical insulation structure in a single manufacturing operation, thereby avoiding the need for separate assembly steps.
Solution Approach 2:
The molding process is designed to be multi-functional, capable of forming different mold compound regions with different properties in a single process. The molding tool (302) and process are universal enough to handle both the thermal conduction region and the insulation region without requiring separate manufacturing operations.
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 approach results in a semiconductor package with enhanced thermal dissipation and electrical insulation, reducing production costs and allowing for optimized design considerations without compromising performance.
Implementation Method 1
The molded plate forms a direct path of the first mold compound between the rear side of the die pad and the mounting surface
Implementation Method 2
performing a molding process that fills the molding chamber with a second mold compound that encapsulates the semiconductor die
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A method of producing a semiconductor package includes providing a molded plate that is formed of a first mold compound, providing a lead frame assembly that includes a lead frame and a semiconductor die mounted on a die pad of the lead frame, arranging the lead frame assembly and the molded plate within a molding chamber of a molding tool such that the molded plate is interposed between the die pad and an interior surface of the molding chamber, and performing a molding process that fills the molding chamber with a second mold compound that encapsulates the semiconductor die.