Organic Stiffener EMI Shield for RF Integration
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Solution Overview
Problem
The challenges of substrate cracking and warpage, as well as electromagnetic interference (EMI), are significant in semiconductor packaging, particularly with the integration of RF and high-powered logic dies, due to the increasing density and fragility of silicon dies and substrates, which affects manufacturability and device reliability.
Innovation Solution
An organic stiffener with integrated EMI shielding is used, comprising a substrate layer with electrical traces and a ground plane, interconnected with heat pipes and copper pillars forming a metallic cage around the CPU die to provide structural support and EMI shielding, mitigating substrate warpage and EMI interference, while allowing for the integration of RF and CPU dies in the same package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the substrate is made thinner to reduce package size, then the form factor requirement is met, but substrate warpage and cracking increase
Solution Approach 1:
The substrate is divided into multiple layers including a first substrate layer, a second substrate layer, and an organic stiffener layer positioned between them. This segmentation allows each layer to have specific functions: the organic stiffener provides mechanical support to prevent warpage and cracking, while the thin overall structure meets form factor requirements.
Solution Approach 2:
The patent uses a composite structure combining different materials: the organic stiffener is formed from a plastic molded compound with a coefficient of thermal expansion (CTE) matched to the silicon die, while the substrate layers provide electrical and mechanical functions. This composite approach allows the thin substrate to maintain reliability.
2Productivity
If RF die and CPU die are placed close together to increase integration density, then circuit density increases, but electromagnetic interference between the dies increases
Solution Approach 1:
The organic stiffener layer acts as an intermediary between the RF die and CPU die. It provides EMI shielding through its conductive properties while maintaining physical separation between the two dies, allowing high integration density without excessive electromagnetic interference.
Solution Approach 2:
The organic stiffener is positioned specifically between the RF die and CPU die to provide localized EMI shielding where it is most needed. The stiffener has a CTE matched to the silicon die, providing thermal and mechanical compatibility in the critical interface region between the two high-density components.
3Reliability
If traditional EMI shielding and stiffening are implemented separately, then EMI protection and structural support are provided, but device complexity and manufacturing cost increase
Solution Approach 1:
The organic stiffener combines multiple functions into a single component: it provides mechanical stiffening to prevent substrate warpage, acts as an EMI shield between the RF die and CPU die, and serves as a thermal management layer with matched CTE. This merging reduces the number of separate components needed.
Solution Approach 2:
The organic stiffener layer performs multiple functions simultaneously: structural support, EMI shielding, and thermal management. This multi-functional component reduces overall device complexity and manufacturing cost compared to using separate components for each function.
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 organic stiffener effectively prevents substrate warpage and cracking, reduces EMI interference between semiconductor dies, enabling the integration of high-powered CPU and RF dies in the same package, improving manufacturability and device reliability, and providing a cost-effective solution by using less expensive materials.
Implementation Method 1
a heat pipe thermally interfaced to a top surface of the functional semiconductor die
Implementation Method 2
a plurality of copper pillars embodied within the sides of the substrate layer between the ground plane of the substrate layer and the heatpipe, each of the plurality of copper pillars being electrically interfaced to both the heatpipe and the ground plane of the substrate; wherein the plurality of copper pillars form the electromagnetic shield to electrically shield the functional semiconductor die
Data Source
AI summary
In accordance with disclosed embodiments, there are provided methods, systems, and apparatuses for implementing an organic stiffener with an EMI shield for RF integration. For instance, in accordance with one embodiment, there is an apparatus having therein: a substrate layer having electrical traces and a ground plane therein; a functional semiconductor die electrically interfaced to the electrical traces of the substrate layer; a heat pipe thermally interfaced to a top surface of the functional semiconductor die; one or more interposers of an organic dielectric material electrically connected to the ground plane of the substrate layer and electrically connected to the heat pipe; in which the one or more interposers form the electromagnetic shield to electrically shield the functional semiconductor die; and further in which the one or more interposers form the organic stiffener are to mechanically retain the substrate layer in a planer form. Other related embodiments are disclosed.