EMI Shielding Process for Semiconductor Connectors Without Contamination
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Solution Overview
Problem
The challenge in semiconductor devices is the difficulty in applying electromagnetic interference (EMI) shielding material without contaminating electrical connectors, particularly in partially molded devices with freestanding connectors, which can lead to electrical shorts or discontinuities.
Innovation Solution
A two-step process is employed to apply EMI shielding material, where a maskless method is used to ensure the electrical connector remains free of shielding material, involving direct jet printing and a cover mask to protect the connector during the application of the shielding layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conformal application of EMI shielding material is used, then electromagnetic interference reduction is improved, but electrical connector contamination increases
Solution Approach 1:
The shielding material application is divided into two distinct steps: first applying material to the encapsulant surface, then applying a second layer that extends onto the substrate while avoiding the connector. This segmentation allows each step to be optimized independently, preventing connector contamination while maintaining EMI shielding effectiveness.
Solution Approach 2:
The first step of applying shielding material to the encapsulant is performed before the connector area is vulnerable to contamination. By establishing the initial shielding layer in advance, the subsequent second step can focus on extending coverage without risking connector contamination, as the critical connector area is avoided during material application.
2Reliability
If mask or tape is used to protect electrical connector, then connector contamination is reduced, but device complexity and potential damage risk increase
Solution Approach 1:
The electrical connector is excluded from the shielding material application area through careful process design. The second step of shielding material application is specifically controlled to extend onto the substrate while deliberately avoiding the connector region, effectively extracting the connector from the contamination risk zone without requiring physical masks or tapes.
Solution Approach 2:
The substrate serves as an intermediary region that allows the shielding material to extend from the encapsulant while naturally terminating before reaching the connector. The material application process uses the substrate geometry and application control as a mediator to prevent direct contact between shielding material and the connector, eliminating the need for additional masking components.
3Area of stationary object
If tight component spacing is used, then device size is reduced, but shielding material application difficulty increases
Solution Approach 1:
The shielding application is segmented into two steps with different coverage areas. The first step covers the encapsulant, and the second step extends onto the substrate while avoiding the connector. This segmentation allows precise control over material placement in tight spaces, as each step can be optimized for its specific region without requiring the entire process to achieve maximum precision simultaneously.
Solution Approach 2:
The shielding material application uses partial action by applying material only to the regions that need shielding (encapsulant and substrate areas), deliberately excluding the connector region. This partial application approach reduces the precision requirements compared to attempting to apply material uniformly across the entire device surface, making the process more manageable in tight component spacing scenarios.
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 two-step process effectively prevents the contamination of electrical connectors by EMI shielding material, ensuring reliable electrical connectivity and preventing shorts or discontinuities, suitable for devices with tight design rules or those incompatible with conventional masking methods.
Implementation Method 1
a maskless method is used to ensure the electrical connector remains free of shielding material, involving direct jet printing
Implementation Method 2
involving direct jet printing and a cover mask to protect the connector during the application of the shielding 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 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. The cover is removed to expose the electrical connector free of shielding material.