Semiconductor Package Potting Structure for Thermal Expansion Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor packages face mechanical stresses and potential damage due to volume changes in potting compounds caused by environmental factors like temperature changes, leading to detachment and loss of insulation properties.
Innovation Solution
Incorporation of expansion structures such as thinned sections, cavities, and movable foils within the potting compound to absorb and manage volume changes, allowing for controlled expansion and shrinkage without damaging the semiconductor package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the potting compound is used to encapsulate the semiconductor die and carrier, then the insulation and protection are improved, but the mechanical stresses from volume changes cause detachment and cracks
Solution Approach 1:
The patent divides the potting compound into multiple layers with different properties. The first layer (closer to the semiconductor die) has lower modulus of elasticity to accommodate volume changes, while the second layer (outer layer) has higher modulus to provide structural support and insulation. This segmentation allows each layer to perform its specific function, resolving the contradiction between maintaining insulation integrity and withstanding mechanical stresses.
Solution Approach 2:
The patent applies different material properties to different regions of the potting compound. The inner layer near the semiconductor components uses a softer material (lower modulus) to locally absorb thermal expansion stresses, while the outer layer uses a harder material (higher modulus) to provide overall structural stability and insulation. This local differentiation of material quality allows the system to simultaneously achieve stress accommodation and structural integrity.
2Strength
If the potting compound is made rigid to maintain structural integrity, then the housing strength is improved, but the detachment and cracks occur due to inability to withstand volume changes
Solution Approach 1:
The housing is segmented into two functional layers: an inner layer with lower modulus of elasticity that flexes with volume changes to prevent detachment, and an outer layer with higher modulus that maintains housing strength and structural integrity. This segmentation resolves the contradiction by assigning different mechanical roles to different parts of the housing structure.
Solution Approach 2:
The patent uses a composite structure with two layers of potting compound having different modulus of elasticity values. The composite design combines the flexibility of the softer inner layer with the rigidity of the harder outer layer, achieving both attachment integrity and housing strength simultaneously.
3Reliability
If the housing is made completely sealed to prevent humidity ingress, then the insulation property is improved, but the expansion and shrinkage cause delaminations and spaces
Solution Approach 1:
The sealed housing is segmented into two layers with different mechanical compliances. The inner softer layer accommodates volume changes through elastic deformation, preventing delamination and space formation, while the outer harder layer maintains the sealed structure's integrity and insulation properties. This segmentation allows the housing to remain both sealed and structurally stable during thermal cycling.
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
Enhances the lifespan of semiconductor packages by mitigating mechanical stresses and maintaining insulation integrity during temperature-induced volume changes.
Implementation Method 1
Expansion and shrinkage of the potting compound of a power electronic frame module, caused for example by the effect of a changing temperature
Data Source
AI summary
A semiconductor package including a die carrier, at least one semiconductor die disposed on the die carrier, a potting compound at least partially covering the die carrier and the semiconductor die, and at least one structure that is configured to withstand a change of the volume of the potting compound occurring under changed external conditions in a targeted manner.