Inner-Layer SMD Mounting in Multi-Layer Substrates for Low Profile
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Solution Overview
Problem
The challenge of manufacturing low-profile integrated circuit devices is exacerbated by surface mount devices with profiles that are too tall, leading to yield loss and device failure due to exposure beyond specified limits, which affects manufacturability and device reliability.
Innovation Solution
A multi-layer substrate design with open areas exposing bond pads at inner layers, allowing surface mount devices to be partially or fully positioned within cavities, reducing their install height and improving manufacturability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface mount devices with standard profiles are used, then device functionality is achieved, but install height exceeds specified limits causing yield loss and device failure
Solution Approach 1:
The patent transitions from mounting surface mount devices on the outer surface of the substrate to mounting them on an inner layer through an open area. This dimensional change allows the device to be positioned within the substrate depth rather than extending above the surface, thereby reducing install height while maintaining electrical connectivity through the inner layer bond pads.
Solution Approach 2:
The surface mount device is nested within the substrate structure by positioning it in an open area that exposes the inner layer. The device becomes partially embedded in the substrate, with portions of the substrate layers surrounding the device, effectively hiding the device within the overall package and reducing its profile height.
2Ease of manufacture
If surface mount devices are reduced in profile to meet height specifications, then manufacturability improves, but device functionality and reliability may be compromised
Solution Approach 1:
Instead of reducing the device profile horizontally, the patent moves the mounting location to a different dimension (inner layer vs. outer surface). This allows standard-profile devices to be used while achieving low overall package height, maintaining both manufacturability with standard devices and reliability through proper electrical connections to the inner layer.
3Productivity
If standard substrate design is used, then manufacturing process is simple, but surface mount devices extend beyond specified limits causing yield loss
Solution Approach 1:
The substrate is segmented into multiple layers with an open area that exposes the inner layer. This segmentation creates a dedicated mounting zone within the substrate structure, allowing surface mount devices to be positioned at a specific depth rather than on the outer surface, thereby controlling the exposed height while maintaining manufacturing efficiency.
Solution Approach 2:
The patent creates a new mounting dimension by exposing the inner layer through the open area. This allows devices to be mounted at a lower vertical position within the substrate stack, reducing the height of exposed components above the substrate surface while maintaining standard manufacturing processes.
Data Source
AI summary
An apparatus includes a primary layer of a substrate. The apparatus includes a secondary layer of the substrate having a first open area that extends through the secondary layer to an inner layer of the substrate. The apparatus includes the inner layer of the substrate that is positioned between the primary layer and the secondary layer. The inner layer includes first component bond pads that are disposed on the inner layer and that are exposed via the first open area of the secondary layer.