Semiconductor Package Interlock Structure for Delamination Resistance
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Solution Overview
Problem
Existing power semiconductor packages face delamination issues due to thermomechanical stress caused by temperature and power cycling, exacerbated by screw elements that increase stress and lead to cracking between the epoxy and baseplate, as well as between the substrate and epoxy.
Innovation Solution
The introduction of a baseplate with through holes and an insulating body featuring locking structures with chamfered shapes that extend through the baseplate, which are filled with epoxy to securely attach the insulating body to the baseplate, reducing delamination by distributing stress and preventing movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If screw elements are used to couple the baseplate to the heatsink and busbar assembly, then mechanical connection is achieved, but inner stress and delamination increase
Solution Approach 1:
The baseplate is segmented with multiple through-holes distributed across its surface, dividing the mechanical connection function into multiple localized attachment points rather than relying on concentrated screw elements. This segmentation distributes the mechanical stress and reduces delamination risk.
Solution Approach 2:
An insulating body with locking structures acts as an intermediary element between the baseplate and the semiconductor devices. These locking structures extend through the through-holes and mechanically interlock with the insulating body, providing a secure connection without requiring traditional screw elements that would increase stress.
2Reliability
If traditional epoxy encapsulation is used, then semiconductor devices are protected and mechanically supported, but delamination occurs under thermomechanical stress
Solution Approach 1:
The locking structures are pre-formed as integral parts of the insulating body before the encapsulation process. This preliminary formation ensures that the bonding interfaces are established in advance, preventing delamination under subsequent thermomechanical stress during operation.
Solution Approach 2:
The insulating body is formed as a composite structure combining epoxy material with integrally formed locking structures. This composite design integrates multiple functions (insulation, mechanical support, and stress distribution) into a single unified component that resists delamination.
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 effectively reduces delamination and stress-induced cracking by maintaining a secure attachment between the insulating body and baseplate, enhancing the structural integrity and reliability of the semiconductor package.
Implementation Method 1
an insulating body, affixed to a top side of the baseplate
Implementation Method 2
forming the insulating body as a monolithic moldable material, wherein the monolithic moldable material flows into the plurality of lock holes
Implementation Method 3
a plurality of locking structures, the plurality of locking structures disposed along a lower periphery of the main portion, and integrally formed within the insulating body, wherein the plurality of locking structures extend through the base plate
Data Source
Figure 1~2
Figure 3~4B
Figure 5A~6
AI summary
A power semiconductor device package. The package may include a baseplate that has a plurality of through holes. The package may also include an insulating body, affixed to a top side of the baseplate The insulating body may include a main portion, to enclose a set of semiconductor devices therein, and a plurality of locking structures, the plurality of locking structures disposed along a lower periphery of the main portion, and integrally formed within the insulating body, wherein the plurality of locking structures extend through the baseplate.