Memory Card Land Grid Array Structure Eliminates Contamination
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Solution Overview
Problem
Traditional memory cards with leadframe structures face issues such as increased manufacturing costs, contamination risks, and limitations in routability due to exposed tie bars and the need for separate caps, which also compromise the form factor and reliability.
Innovation Solution
A memory card fabricated using a land grid array (LGA) structure and a two-stage molding process, eliminating exposed tie bars and the need for a separate cap, while providing signal routing capabilities similar to laminate substrates and the cost benefits of leadframe-based cards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a leadframe structure is used in memory cards, then manufacturing costs are reduced, but exposed tie bars create contamination risks and reliability issues
Solution Approach 1:
The patent extracts and removes the problematic exposed tie bars from the leadframe structure by implementing a planarization layer that covers and encapsulates them. This extraction eliminates the contamination source while retaining the cost benefits of the leadframe approach.
Solution Approach 2:
The patent nests multiple protective structures within each other: the planarization layer is embedded within the molded encapsulant, which itself is nested within the overall memory card housing. This nested arrangement provides multiple barriers against contamination while maintaining structural integrity.
2Reliability
If a separate cap is added to cover components on the substrate, then component protection is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the protective cap function with the molded encapsulant structure. The molded encapsulant simultaneously serves as both the protective covering and the structural housing, eliminating the need for a separate cap component and its associated assembly steps.
Solution Approach 2:
The molded encapsulant is designed to perform multiple functions simultaneously: it protects internal components, provides structural support, houses the leadframe assembly, and creates the final memory card form factor. This multi-functionality eliminates the need for separate protective components.
3Reliability
If a separate cap is mechanically coupled to the substrate, then component coverage is achieved, but manufacturing yield decreases and contamination susceptibility increases
Solution Approach 1:
The patent combines the protective coverage function with the primary molded encapsulant structure, eliminating the need for separate mechanical coupling operations. The encapsulant is molded directly over the components in a single integrated process, ensuring complete coverage without additional assembly steps that could introduce contamination or reduce yield.
4Ease of manufacture
If leadframe based memory cards are used, then cost benefits are achieved, but routability between components is limited
Solution Approach 1:
The patent transitions from the traditional two-dimensional leadframe trace routing to a three-dimensional routing architecture. Conductive vias penetrate through the planarization layer and molded encapsulant, enabling vertical and multi-layer routing paths that dramatically increase routing capacity while maintaining leadframe cost benefits.
Data Source
AI summary
A memory card comprising a substrate which has a plurality of contacts, at least one die pad, and a plurality of traces. The contacts, the die pad and the traces are disposed in spaced relation to each other and each define opposed first and second surfaces. Mounted to the first surface of the die pad is at least one electronic component which is electrically connected to at least one of the contacts either directly or via one or more of the traces. A first encapsulation part covers the second surfaces of the die pad and the traces, with the second surfaces of the contacts being exposed in the first encapsulation part. A second encapsulation part covers the electronic component and the first surfaces of the die pad, the contacts, and the traces. The first and second encapsulation parts collectively define a body of the memory card which includes a bottom surface having the second surfaces of the contacts exposed therein.