Multi-layer IC Package with Rigid Reinforcement for Warpage Control
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Solution Overview
Problem
Current materials for high-performance wireless radios on integrated circuit (IC) assemblies face challenges in mechanical stability and surface roughness, leading to increased conductor losses and warpage issues, especially when trying to cover broad frequency bands like 7 GHz around 60 GHz, while maintaining low loss and cost-effectiveness.
Innovation Solution
A multi-layer package assembly is introduced, featuring a structurally rigid reinforcement layer with lower surface roughness dielectric layers on either side, composed of materials like prepreg or liquid crystal polymer (LCP), which reduces warpage and conductor losses by using a core-like material with low loss dielectric properties and selective metal plating on smoother layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a thick dielectric layer is used between antenna and ground plane to cover broad frequency band, then frequency coverage is improved, but substrate thickness increases leading to mechanical instability and warpage
Solution Approach 1:
The patent uses a composite structure combining flexible low-loss dielectric material with a rigid reinforcement layer (such as LTCC or ceramic). This composite approach allows the flexible material to provide broad frequency coverage while the rigid reinforcement layer maintains mechanical stability and prevents warpage, resolving the contradiction between frequency adaptability and mechanical stability.
Solution Approach 2:
The substrate is segmented into multiple functional layers: a flexible low-loss dielectric layer for electrical performance and broad frequency coverage, and a separate rigid reinforcement layer for mechanical stability. This segmentation allows each layer to independently optimize its function without compromising the other.
2Stability of the object's composition
If more rigid materials like LTCC are used to improve mechanical stability, then warpage is reduced, but material cost increases
Solution Approach 1:
Instead of making the entire substrate from expensive rigid LTCC material, the patent applies rigid reinforcement only in specific locations where mechanical support is needed, such as beneath the antenna and ground plane. The rest of the substrate uses cheaper flexible low-loss dielectric material, achieving mechanical stability while reducing overall manufacturing cost.
3Stability of the object's composition
If structurally rigid configuration is used to reduce warpage, then mechanical stability is improved, but surface roughness increases leading to higher conductor losses
Solution Approach 1:
The patent introduces a vertical dimension to the structure by stacking multiple layers with different properties. The rigid reinforcement layer is positioned in the vertical dimension beneath the conductive elements, providing mechanical support without directly contacting the signal paths. This dimensional separation allows the conductive elements to remain on smooth surfaces while the rigid layer handles mechanical stabilization.
Data Source
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AI summary
Embodiments of the present disclosure describe a multi-layer package with antenna and associated techniques and configurations. In one embodiment, an integrated circuit (IC) package assembly includes a first layer having a first side and a second side disposed opposite to the first side a second layer coupled with the first side of the first layer, one or more antenna elements coupled with the second layer and a third layer coupled with the second side of the first layer, wherein the first layer is a reinforcement layer having a tensile modulus that is greater than a tensile modulus of the second layer and the third layer. Other embodiments may be described and/or claimed.