Apertured Package Lid Structure for Semiconductor Heat Extraction
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Solution Overview
Problem
Conventional semiconductor package solutions face a trade-off between mechanical rigidity and thermal dissipation, with stiffener rings providing high thermal performance but inadequate mechanical support, and lidded solutions offering mechanical strength at the cost of thermal efficiency. Additionally, conventional lidded solutions are not suitable for BGA implementations and have reliability issues with molded chip modules.
Innovation Solution
A semiconductor package design featuring a package lid structure with one or more apertures aligned with the semiconductor die component, allowing direct thermal coupling to the die via a thermally conductive plate or thermal exchange structure, thereby optimizing both mechanical and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional lidded package structure is used to provide mechanical rigidity, then mechanical strength is improved, but thermal dissipation performance deteriorates due to the solid lid blocking thermal pathways
Solution Approach 1:
The package lid is segmented by introducing apertures (openings) through it, transforming the solid lid into a structure with thermal pathways. This segmentation allows thermal energy to pass through the lid while the remaining lid material continues to provide mechanical support and rigidity to the package
Solution Approach 2:
Different regions of the package lid serve different functions: the solid portions provide mechanical strength and structural support, while the aperture regions provide thermal conduction pathways. This local differentiation of properties resolves the contradiction between mechanical strength and thermal dissipation
2Temperature
If a stiffener ring is used instead of a package lid, then thermal dissipation performance is improved through direct thermal coupling, but mechanical rigidity deteriorates due to lack of structural support
Solution Approach 1:
The invention merges the functions of both the stiffener ring and package lid by creating a lid with apertures. The lid structure combines the mechanical support function of a stiffener ring with the thermal pathways of an open structure, while adding the protective enclosure function of a lid, thereby achieving both thermal performance and mechanical rigidity
3Temperature
If a metal-based thermal interface material is used in a conventional lidded package, then thermal dissipation is improved, but reliability deteriorates because the metal TIM cannot withstand solder reflow temperatures in BGA implementations
Solution Approach 1:
The aperture structure enables a two-stage TIM application approach: first, an organic/polymeric TIM with low melting point is applied and withstands the solder reflow process; second, a metal-based TIM with high thermal conductivity is applied in the aperture region after reflow, providing superior thermal dissipation without being exposed to reflow temperatures that would damage it
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 package lid structure with apertures enables efficient thermal dissipation through a single TIM layer while maintaining mechanical integrity, and allows the use of metal-based TIMs even in BGA implementations, enhancing overall thermal and mechanical performance.
Implementation Method 1
a thermally conductive plate disposed in the aperture of the package lid structure and having a seventh surface thermally coupled to the fourth surface of the semiconductor chip component
Implementation Method 2
the seventh surface is thermally coupled to the eighth surface using one of a metal-based thermal interface material or a polymeric thermal interface material
Data Source
AI summary
A semiconductor package includes a substrate having opposing first and second surfaces as well as a semiconductor chip component disposed at the second surface and having third and fourth opposing surfaces. A package lid structure is affixed to the second surface of the substrate and the fourth surface of the semiconductor chip component, and has a planar component overlying the semiconductor chip component and having a fifth surface facing the fourth surface and an opposing sixth surface. The planar component includes an aperture extending between the fifth surface and the sixth surface so as to expose at least a portion of the fourth surface of the semiconductor chip component. A thermal exchange structure can be mounted on the package lid structure to form a thermal extraction pathway with the semiconductor die component via the aperture, either directly or via an interposing thermally conductive plate.