Sintered Metallic Layer for Thermal Stress Management in Semiconductor Packages
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Solution Overview
Problem
Semiconductor die integration into packages often results in thermal stresses that can lead to cracking or performance alterations, particularly in high-power devices, where existing solutions fail to adequately address the mechanical and thermal challenges.
Innovation Solution
A semiconductor die is attached to a thermally conductive substrate using a sintered metallic layer and a thermally conductive flow layer, which includes a solder material with a suitable melting point, to enhance heat dissipation and mechanical stability, thereby reducing stress and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semiconductor die is attached directly to a thermally conductive substrate using conventional methods, then the attachment process is simple, but thermal stresses cause cracking or performance alterations
Solution Approach 1:
A sintered metallic layer is introduced as an intermediary between the semiconductor die and the thermally conductive substrate. This intermediate layer acts as a stress buffer that accommodates differential thermal expansion, preventing cracking while maintaining thermal conduction pathways. The sintered metal layer absorbs thermal stresses that would otherwise transfer directly to the die, thereby improving reliability without excessive complexity.
Solution Approach 2:
The attachment structure employs composite materials comprising a sintered metallic layer with specific thermal and mechanical properties. This composite structure combines the thermal conductivity needed for heat dissipation with the mechanical flexibility required to manage thermal stresses, resolving the contradiction between reliability and complexity.
2Power
If high-power semiconductor devices are used to increase power output, then the power dissipation capability is improved, but thermal stresses increase leading to cracking
Solution Approach 1:
The sintered metallic layer serves as a stress-absorbing intermediary that decouples the high-power die from the rigid substrate. This intermediate structure allows the device to handle higher power dissipation by preventing stress transfer, thereby enabling increased power output without proportionally increasing thermal stress damage.
Solution Approach 2:
The sintered metallic layer changes the mechanical and thermal parameters of the attachment interface. By adjusting the sintering process and material composition, the layer achieves optimal balance between thermal conductivity and stress absorption capacity, allowing high-power operation with reduced harmful thermal stresses.
3Productivity
If conventional attachment methods are used to simplify the manufacturing process, then the manufacturing complexity is reduced, but production yield decreases due to cracking
Solution Approach 1:
The sintered metallic layer is applied to the die surface before final assembly, performing preliminary stress management. This preliminary action prevents cracking during subsequent packaging and operation, thereby improving production yield without requiring complex post-assembly interventions.
Solution Approach 2:
The sintering process transforms the metallic layer's physical parameters to achieve optimal attachment properties. By controlling sintering temperature, time, and atmosphere, the process achieves reliable attachment with reduced cracking, improving yield while maintaining reasonable manufacturing simplicity.
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 increases the reliability and production yield of high-power semiconductor devices by effectively managing thermal and mechanical stresses, allowing for reliable attachment of gallium nitride and silicon die to copper flanges or lead frames, even with differing coefficients of thermal expansion.
Implementation Method 1
a sintered metallic layer disposed between the lower surface of the semiconductor die and the thermally conductive substrate
Implementation Method 2
a thermally conductive flow layer disposed between the sintered metallic layer and coupling the sintered metallic layer and semiconductor die to the thermally conductive substrate
Implementation Method 3
which includes a solder material with a suitable melting point
Data Source
AI summary
An electronic device includes a semiconductor die having a lower surface, a sintered metallic layer underlying the lower surface of the semiconductor die, a thermally conductive flow layer underlying the sintered metallic layer, and a thermally conductive substrate underlying the thermally conductive flow layer.