Stress Relief Substrate for Clip-Lead Semiconductor Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor device packages are susceptible to thermomechanical stress, which can lead to significant and potentially permanent damage, especially due to the differential thermal expansion between clip leads and die substrates, causing failures in the semiconductor dies and integrated components.
Innovation Solution
Incorporating a stress relief substrate with a thermal expansion coefficient closer to that of the semiconductor die, which bridges the thermal expansion difference between the clip lead and the die substrate, distributing mechanical forces and reducing stress on the semiconductor die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clip lead is fixedly attached to the die terminal, then electrical connection is achieved, but thermomechanical stress damages the semiconductor die due to differential thermal expansion
Solution Approach 1:
A stress relief substrate is introduced as an intermediary component between the clip lead and the die terminal. This substrate has a coefficient of thermal expansion that bridges the gap between the clip lead material (e.g., copper) and the die substrate material (e.g., silicon), thereby mediating the thermal expansion differential and reducing thermomechanical stress on the semiconductor die while maintaining electrical connection reliability.
Solution Approach 2:
The stress relief substrate is made from a composite material or a material with specifically engineered properties that provide a intermediate coefficient of thermal expansion. This allows the substrate to accommodate the differential expansion between the metal clip lead and the semiconductor die substrate, distributing and reducing mechanical stress on the die.
2Reliability
If the clip lead is made from metal with high electrical conductivity, then electrical connection is improved, but the coefficient of thermal expansion difference increases causing greater thermomechanical stress
Solution Approach 1:
The stress relief substrate serves as a mediator that decouples the thermal expansion properties from the electrical connection requirements. The clip lead can be made from highly conductive metal (e.g., copper) for optimal electrical performance, while the substrate provides the intermediate thermal expansion properties, thus resolving the conflict between electrical conductivity and thermal expansion compatibility.
3Device complexity
If the die terminal is directly connected to the clip lead, then device complexity is reduced, but stress concentration occurs leading to cracking in passivation layers
Solution Approach 1:
The stress relief substrate is introduced as an intermediary layer between the die terminal and clip lead. While this adds one additional component, it significantly reduces the risk of cracking in passivation layers by distributing thermomechanical stress, thereby improving the overall strength and reliability of the connection structure.
Solution Approach 2:
The stress relief substrate increases the contact surface area between the clip lead assembly and the die terminal. This dimensional expansion distributes the mechanical load over a larger area, reducing stress concentration that would otherwise lead to cracking in the passivation layers and intermetallic dielectric layers.
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
The stress relief substrate mitigates thermomechanical stress, reducing the risk of damage to the semiconductor die and its layers, thereby enhancing the robustness and reliability of the package.
Implementation Method 1
The substrate is configured to bridge a difference between a coefficient of thermal expansion of the clip lead and a coefficient of thermal expansion of a die substrate of the semiconductor die
Implementation Method 2
The clip lead may be electrically connected to the die terminal through said plurality of conductive vias
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Aspects of the present disclosure relate to a semiconductor device package and a method for manufacturing the same. The semiconductor device package according to the present disclosure comprises a semiconductor die having an electronic component integrated thereon and having a die terminal that is electrically connected to the electronic component, a stress relief substrate fixedly and electrically connected to the die terminal, and a clip lead. The substrate is configured to provide an electrical short between the clip lead and the die terminal. The stress relief substrate may form an interface between the clip lead and the semiconductor die and can thereby reduce stress exerted on the semiconductor die by said clip lead.