Selective Molding of Electronic Modules via Laser-Trenched Tape

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Solution Overview

Problem

Conventional partial molding techniques for electronic modules often result in air bubbles or voids due to fluid adhesion, leading to low yield rates and increased costs due to complex mold designs and redesigns for different configurations, especially when encapsulating components like CMOS image sensors or LEDs.

Innovation Solution

A method involving a circuit substrate with a predetermined area and ground pads, where a tape is applied and laser-trenched to create a molding member that forms an angle close to 90 degrees with the substrate, allowing for selective molding without complex molds, and an EMI shielding layer is formed to connect with the ground pads, enabling the placement of optoelectronics without encapsulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional partial molding is achieved by mold chase, then electronic components can be protected, but air bubbles or voids form due to fluid adhesion leading to low yield rate

Engineering Contradiction:

Improveprotection of electronic componentsVSAvoidyield rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent removes the mold chase entirely from the process. Instead of using a traditional mold chase that requires draft angles and complex removal procedures, the invention applies molding material directly to the circuit board in a simplified process, eliminating the source of air bubbles and voids associated with mold chase methodology

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical mold chase system with a direct application method where molding material is applied and cured in place. This substitution eliminates the mechanical complexity of mold chase insertion and removal, thereby preventing air bubble formation during the molding process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If mold chase is used for partial molding, then electronic components can be protected, but complex mold designs and redesigns are required for different configurations increasing cost

Engineering Contradiction:

Improveprotection of electronic componentsVSAvoidmold design complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal molding process that can accommodate different electronic component configurations without requiring redesign of mold chases. The method allows the same basic process to be applied to various layouts and shapes, making the system adaptable and eliminating the need for custom mold designs for each configuration

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of designing complex mold chases to fit specific component configurations, the patent inverts the approach by applying molding material directly to match the desired configuration. This reverse methodology simplifies the process by adapting the material application to the components rather than forcing components into pre-designed mold geometries

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If mold chase is used for partial molding, then electronic components can be protected, but draft angle must be preserved reducing overall usage of the printed circuit board

Engineering Contradiction:

Improveprotection of electronic componentsVSAvoidusage of printed circuit board

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent removes the mold chase entirely, eliminating the requirement for draft angles. This allows the molding material to be applied directly over the entire required area of the circuit board without needing to reserve space for mold chase removal, thereby maximizing the usable area of the printed circuit board

Inventive Principle:

Principle #2Taking out (Extraction)

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 method enables efficient selective molding with reduced air bubbles, increased yield rates, and cost-effective production by avoiding complex mold designs, while providing effective EMI shielding for optoelectronics.

Implementation Method 1

laser is used to trench the tape above the ground pad

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

UV light may be used to shine on the tape and removed thereby

Methodology Applied

Scientific EffectPhoto-oxidation: Photo-oxidation

Implementation Method 3

heating may be used to facilitate the process

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9881875B2Electronic module and method of making the same

Publication Date: 2018.01.30 UNIVERSAL SCIENTIFIC INDUSTRIAL (SHANGHAI) CO LTD

AI summary

A method of manufacturing electronic module is provided. The method can perform selective partial molding by forming the tapes in a predetermined area on the circuit substrate, setting electronic components out the predetermined area on the circuit substrate, forming the molding member encapsulating the whole circuit substrate and removing the tapes along of the molding member thereon. Following, forming an EMI shielding layer on the molding member and setting optoelectronics in the predetermined area on the circuit substrate could protect the electronic components from electromagnetic disturbance and avoid the optoelectronics being encapsulated.