Spring Biased Lid for Semiconductor Chip Package Thermal Management
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Solution Overview
Problem
Conventional semiconductor chip packages experience thermal interface material degradation due to repeated thermal cycling, leading to increased thermal resistance and reduced heat transfer efficiency, which is often mitigated by reducing chip performance rather than addressing the root cause.
Innovation Solution
Incorporating a spring biasing mechanism that allows the lid to translate and apply compressive force on the thermal interface material, reducing the likelihood of defect formation and closing existing cracks or voids, thereby maintaining effective heat transfer without compromising chip performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid adhesive connection is used to secure the lid to the substrate, then the lid is firmly fixed and provides structural stability, but the thermal interface material degrades over time due to thermal cycling, leading to increased thermal resistance
Solution Approach 1:
The patent transitions from a static rigid adhesive connection to a dynamic spring-based connection that allows controlled movement. The spring mechanism enables the lid to move relative to the substrate in response to thermal expansion and contraction, maintaining continuous contact pressure on the thermal interface material while accommodating dimensional changes during thermal cycling, thereby preventing degradation and maintaining thermal reliability.
Solution Approach 2:
The patent changes the mechanical parameter of the connection from fixed/rigid to compliant/elastic. By introducing springs with specific force constants, the system can dynamically adjust the contact force between the lid and thermal interface material, ensuring optimal thermal contact pressure is maintained across varying temperature conditions without causing stress damage to the thermal interface material.
2Ease of manufacture
If the lid is rigidly fixed to the substrate, then manufacturing is simple, but thermal resistance increases due to thermal interface material degradation from thermal cycling
Solution Approach 1:
The spring-based lid connection provides a dynamically adaptive assembly process. The springs are positioned and oriented to naturally accommodate thermal expansion patterns, allowing the lid to self-adjust during operation. This maintains effective thermal contact without requiring complex adjustment mechanisms or precision alignment procedures, keeping manufacturing relatively simple while dramatically improving heat transfer efficiency by preventing thermal interface material degradation.
3Stability of the object's composition
If no compressive force is applied to the thermal interface material, then the lid and substrate can expand freely during thermal cycling, but thermal resistance increases due to defect formation and voids in the thermal interface material
Solution Approach 1:
The spring mechanism applies preliminary compressive force to the thermal interface material before thermal cycling begins and maintains this force throughout operation. This pre-compression counteracts the tendency of the thermal interface material to develop defects and voids during thermal expansion and contraction, preventing degradation before it occurs and ensuring reliable heat transfer throughout the device lifecycle.
Solution Approach 2:
The springs act as mechanical cushioning elements that absorb and compensate for thermal expansion stresses. By positioning the springs to apply continuous compressive force, the system cushions the thermal interface material against the harmful effects of repeated thermal cycling, preventing crack formation and void development that would otherwise increase thermal resistance and reduce heat transfer reliability.
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 spring biasing mechanism effectively compresses the thermal interface material, reducing thermal resistance and preventing void formation, thus enhancing heat transfer efficiency while maintaining chip performance.
Implementation Method 1
a spring biasing mechanism operable to bias the lid away from the package substrate so that the lid, when subjected to a compressive force, can translate toward the package substrate and impart a compressive force on the thermal interface material
Data Source
AI summary
Various semiconductor chip packages are disclosed. In one aspect, a semiconductor chip package is provided that includes a package substrate that has a first edge and a second edge opposite to the first edge. A semiconductor chip is mounted on the package substrate. A thermal interface material is positioned on the semiconductor chip. A lid is positioned over the thermal interface material. A spring biasing mechanism is included that is operable to bias the lid away from the package substrate so that the lid, when subjected to a compressive force, can translate toward the package substrate and impart a compressive force on the thermal interface material.