EMI Shielding Layout for Semiconductor Packages With Clean Connectors
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Solution Overview
Problem
Existing methods for applying electromagnetic interference (EMI) shielding material to semiconductor devices, particularly in high-frequency applications, face challenges in accurately shielding without covering electrical connectors, leading to potential electrical shorts or discontinuities, and are inefficient due to design constraints and productivity issues.
Innovation Solution
A two-step process involving direct jet printing and light sintering is used to apply EMI shielding material, ensuring the electrical connectors remain free of shielding material by using maskless techniques and localized heating to form a durable, conductive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conformal EMI shielding material is applied over the encapsulant, then EMI shielding effectiveness is improved, but the electrical connector may be contaminated with shielding material causing electrical shorts or discontinuities
Solution Approach 1:
The EMI shielding process is divided into two distinct steps: first applying shielding material to the encapsulant surface, then using a physical barrier (mask) to protect the electrical connector during subsequent shielding material application. This segmentation allows each component to receive appropriate shielding while preventing contamination of the connector.
Solution Approach 2:
A mask or barrier material is introduced as an intermediary element between the EMI shielding material and the electrical connector. This intermediary prevents direct contact between the shielding material and connector, eliminating the risk of electrical shorts while maintaining shielding effectiveness.
2Manufacturing precision
If spray coating method is used for selective EMI shielding, then shielding accuracy is improved, but productivity decreases due to reduced units per hour
Solution Approach 1:
The patent replaces the spray coating mechanical system with a direct application method using screens or stencils. This substitution maintains precise material placement accuracy while enabling faster processing speeds and higher productivity through more efficient material deposition.
3Object-affected harmful factors
If sputtering method is used for EMI shielding, then shielding effectiveness is improved, but package design is constrained due to minimum clearance requirements between shielding area and cap
Solution Approach 1:
The patent transitions from planar sputtering deposition to a vertical/direct application approach using screens or stencils. This dimensional change eliminates the need for minimum clearance between shielding areas and caps, as the material is applied directly through the screen pattern without requiring lateral clearance for cap movement or deposition zone.
4Reliability
If mask and tape are used to isolate electrical connector during shielding, then connector protection is improved, but manufacturing complexity increases and potential damage to connector may occur
Solution Approach 1:
The patent combines the shielding pattern definition and connector protection functions into a single integrated screen or stencil component. This merging eliminates the need for separate mask and tape applications, reducing process complexity while maintaining reliable connector protection through the integrated barrier design.
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
The method effectively shields semiconductor devices from EMI while maintaining connector integrity, improving productivity and reducing design constraints, suitable for devices with tight spacing and complex designs.
Implementation Method 1
A two-step process involving direct jet printing and light sintering is used to apply EMI shielding material, ensuring the electrical connectors remain free of shielding material by using maskless techniques and localized heating to form a durable, conductive layer.
Data Source
AI summary
A semiconductor device has a substrate and encapsulant deposited over the substrate. An electrical connector is disposed over the substrate outside the encapsulant. An antenna can be formed over the substrate. A first shielding material is disposed over a portion of the encapsulant without covering the electrical connector with the first shielding material. The first shielding material is disposed over the portion of the encapsulant and the portion of the substrate using a direct jet printer. A light source emitting an ultraviolet light or intense pulsed light is directed at the first shielding material to induce sintering. A cover is disposed over the electrical connector. A second shielding material is disposed over the encapsulant to prevent the second shielding material from reaching the electrical connector. The second shielding material overlaps the first shielding material and covers a side surface of the encapsulant and a side surface of the substrate.