Organic Laminate Stack Ups Embedding Discrete Devices for RF Parasitic Reduction
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Solution Overview
Problem
Current printed circuit board assembly processes, particularly surface mount assembly, face challenges in microminiaturization, reliability, and performance due to increased system speeds and frequencies, which result in parasitic issues and reduced system performance.
Innovation Solution
The development of multi-layer organic stack-ups that embed active and passive discrete devices within organic layers and cavities, utilizing materials like liquid crystalline polymers and prepreg layers to reduce layer counts and increase component density, along with novel fabrication techniques such as photolithographic circuitization and encapsulation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If surface mount assembly is used to reduce size, then system size is reduced, but parasitics increase and performance deteriorates at high frequencies
Solution Approach 1:
The patent transitions from two-dimensional surface mounting to three-dimensional embedding within organic laminate layers. Discrete devices are positioned within cavities formed in internal organic layers, allowing vertical integration and reducing horizontal interconnect lengths that cause parasitics at high frequencies.
Solution Approach 2:
Discrete devices are nested within cavities formed in organic laminate layers. The devices are enclosed by prepreg layers and positioned between conductive layers, creating a nested structure that reduces overall footprint while minimizing interconnect path lengths.
2Quantity of substance
If component density is increased, then system size is reduced, but manufacturing complexity increases
Solution Approach 1:
Cavities are formed in organic layers before device attachment. Conductive layers are patterned and positioned in advance, and prepreg layers are prepared with adhesive properties. This preliminary structuring simplifies the subsequent device embedding process while achieving high density.
Solution Approach 2:
The patent uses composite organic laminate structures combining different organic layers with embedded discrete devices. The heterogeneous stack-up integrates conductive layers, dielectric organic layers, and device-containing cavities into a unified manufactured assembly, managing complexity through material differentiation.
3Reliability
If interconnect lengths are reduced to minimize parasitics, then performance improves, but device embedding complexity increases
Solution Approach 1:
The patent merges the formation of cavities, conductive layers, and device attachment into an integrated embedding process. Multiple functions are combined in a single manufacturing sequence, reducing the need for separate operations while achieving short interconnect lengths for high-frequency performance.
Data Source
AI summary
Organic laminate stack ups are disclosed for a variety of applications, including high frequency RF applications. One or more inner core layers may be disposed between outer layers along with bondply or prepreg layers as needed. Discrete devices, including surface mount components and flip chips, may be embedded within the organic laminate stack up structures. The embedding of the discrete devices, which may be active or passive devices, may be in the form of a layer of bondply or prepreg encapsulating the discrete devices. In addition or in the alternative, cavities may be formed in at least the outer layers for housing discrete devices, which include surface mount components, flip chips, and wire bonded integrated circuits. A variety of caps may be utilized to seal the cavities. Further, shielding may be provided for the organic laminate stack up structure, including through a wall of vias or a plated trench cut along at least one side of the stack up structure. Each stack up structure may be packaged in a variety of ways, including as a surface mount component, ball grid array, or land grid array.