Selective EMI Shielding With UV-Curable Ink for Connector Isolation

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Solution Overview

Problem

Conformal application of electromagnetic interference (EMI) shielding material in semiconductor devices with freestanding electrical connectors is challenging, often leading to electrical shorts or discontinuities due to the difficulty in isolating and protecting the connectors during shielding material deposition.

Innovation Solution

Utilizing ultraviolet (UV) curable ink material to form selective shielding that blocks the progression of shielding material away from electrical connectors, ensuring precise control and avoiding contact through rapid curing and controlled deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conformal application of EMI shielding material is used, then EMI shielding effectiveness is improved, but electrical connector reliability deteriorates due to potential shorts or discontinuities

Engineering Contradiction:

ImproveEMI shielding effectivenessVSAvoidelectrical connector reliability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

A mask is applied to the electrical connector before the conformal coating process to protect it from shielding material deposition. This preliminary protective action prevents the connector from being exposed to harmful shielding material while allowing the rest of the device to receive full EMI shielding coverage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The device is segmented into two zones: a shielded zone for the semiconductor die and encapsulant, and an unshielded zone for the electrical connector. This spatial segmentation allows differential treatment of shielding application, ensuring the connector remains free of shielding material while other components receive comprehensive EMI protection.

Inventive Principle:

Principle #1Segmentation

2Reliability

If mask or tape is used to isolate electrical connector, then connector protection is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveelectrical connector protectionVSAvoidmasking process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The mask material is selected to be substantially opaque to UV light, creating a clear visual distinction between masked and unmasked areas. This optical property allows the mask to serve dual purposes: physical protection during coating and UV light blocking during curing, simplifying the overall process.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The mask automatically performs multiple functions simultaneously: it protects the connector from shielding material deposition and blocks UV light during the curing process. This self-service capability eliminates the need for separate protective measures and reduces manufacturing complexity.

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If mask is used for tight component spacing, then connector isolation is improved, but risk of connector damage increases

Engineering Contradiction:

Improveconnector isolation precisionVSAvoidelectrical connector structural integrity

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

A thin film mask is used that can conform to tight component spacing without requiring significant clearance. The flexible nature of the thin film allows it to be applied in confined spaces while maintaining effective isolation, reducing the risk of damage compared to rigid masking materials.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The mask is applied in advance to create a protective barrier that prevents both shielding material accumulation and potential mechanical damage during the coating process. This preliminary protective action eliminates the need for forceful removal operations that could damage the connector.

Inventive Principle:

Principle #9Preliminary anti-action

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

Prevents electrical shorts and ensures reliable shielding without disrupting the functionality of freestanding connectors, maintaining the integrity of semiconductor device performance.

Implementation Method 1

An electromagnetic shielding material is commonly conformally applied over the encapsulant. The electromagnetic shielding layer reduces or inhibits EMI, RFI, and other inter-device interference

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

Methodology Applied

Scientific EffectUV curing: Photopolymerisation

Data Source

PatentUS20250218985A1Semiconductor Device and Method of Forming Selective Shielding Using UV Curable Ink

Publication Date: 2025.07.03 STATS CHIPPAC LTD

AI summary

A semiconductor device has a substrate and an electrical component disposed over a surface of the substrate. An antenna can be formed within the substrate. An encapsulant is deposited over the surface of the substrate. An ink material is deposited over the surface of the substrate. The ink material can be a curable epoxy. The ink material is formed as a straight wall, curved wall, stepped wall, stepped convex wall, and such. The ink material can be stacked with a first ink material deposited on the surface of the substrate and a second ink material deposited over the first ink material. A shielding material is disposed over the encapsulant with the ink material blocking progression of the shielding material. An electrical connector is disposed over the surface of the substrate outside the ink material to avoid contact with the shielding material.