Transfer Molding for Irregular Memory Card Encapsulation
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Solution Overview
Problem
Conventional memory card fabrication methods are costly, complex, and inefficient, particularly when producing irregular shapes like Micro-SD, MMC-Micro, and M2, as they require high-cost tools like water jets and lasers, which lead to unstable cutting paths, environmental pollution, and increased risk of chip-out or cracking.
Innovation Solution
A method involving a circuit board with predefined shape units, a thin film, and transfer molding to form encapsulants, followed by cutting away connecting portions to create memory cards without the need for shape cutting processes, simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water jet or laser cutting is used to cut packages of irregular shape, then cutting ability is improved, but manufacturing cost increases and environmental pollution occurs
Solution Approach 1:
The patent extracts the shape definition function from the cutting process itself and transfers it to the mold cavity design. The mold cavities are pre-designed with the exact irregular shapes needed, so the encapsulant is formed directly in the desired shape without requiring complex cutting operations. This eliminates the need for expensive water jet or laser cutting equipment while achieving the same manufacturing capability.
Solution Approach 2:
Instead of cutting the encapsulant to shape after formation (subtractive approach), the patent inverts the approach by forming the encapsulant directly in the desired shape through mold cavities (additive approach). This reversal eliminates the need for complex cutting tools and reduces manufacturing costs significantly.
2Manufacturing precision
If water jet with abrasive material is used for cutting, then cutting precision is improved, but environmental pollution and process instability increase
Solution Approach 1:
The patent converts the harmful abrasive material from a necessary component into an unnecessary element by eliminating the cutting process entirely. The mold cavities provide the shape definition without requiring abrasive materials, thus converting the harmful cutting process into a benign molding process that produces no pollution.
3Manufacturing precision
If water jet or laser cutting is used to cut irregular shapes, then shape accuracy is improved, but chip-out or cracking risk increases
Solution Approach 1:
The patent performs the shape definition action in advance during mold cavity design and encapsulant formation, rather than attempting to cut the shape after the encapsulant is formed. The mold cavities are pre-configured with the exact irregular shapes needed, so the encapsulant emerges already shaped with no risk of chip-out or cracking from subsequent cutting operations.
4Strength
If conventional high frequency welding is used to bond sheets, then bonding strength is improved, but structure complexity and fabrication cost increase
Solution Approach 1:
The patent merges the bonding function into the encapsulant structure itself. The encapsulant material is applied to bond the circuit board units together and to the housing in a single operation, eliminating the need for separate high frequency welding processes. This integration simplifies the fabrication process while maintaining structural integrity.
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
This approach eliminates the need for expensive cutting tools, stabilizes the cutting process, improves yield, and reduces fabrication costs while avoiding chip-out or cracking, enabling efficient production of irregularly shaped memory cards.
Implementation Method 1
a pressing step of pressing the encapsulant material with a pressing force of 50 to 100 tons under a heated state at a temperature of 80 to 100° C. for 10 to 30 seconds
Data Source
AI summary
A memory card and method for fabricating the same are disclosed, which includes mounting and electrically connecting at least a chip to a circuit board unit having a predefined shape of a memory card; attaching a thin film to the surface of the circuit board unit opposed to the surface with the chip mounted thereon; covering the circuit board unit and the thin film by a mold so as to form a mold cavity having same shape as the circuit board unit but bigger size; filling a packaging material in the mold cavity so as to form an encapsulant encapsulating the chip and outer sides of the circuit board unit, thus integrally forming a memory card having the predefined shape. The present invention eliminates the need to perform a shape cutting process by using water jet or laser as in the prior art, thus reducing the fabricating cost and improving the fabricating yield.