Shielding Layer in TSV Interposer for EMI Isolation
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Solution Overview
Problem
Semiconductor devices face challenges in isolating themselves from electromagnetic interference (EMI) and radio frequency interference (RFI), which can interfere with their operation, especially in high-frequency applications where multiple integrated passive devices are used.
Innovation Solution
A method of forming a shielding layer over a semiconductor die and extending it through a trench in the encapsulant and substrate, providing effective coverage to reduce EMI and RFI by routing interfering signals to a low impedance ground point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shielding layer is formed over the semiconductor die, then EMI and RFI protection is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The shielding layer is integrated with the encapsulant structure by forming the shielding layer within a trench that is filled with encapsulant material. This merging of the shielding function with the existing encapsulation structure provides EMI/RFI protection without requiring a completely separate shielding structure, thus improving reliability while limiting the increase in device complexity.
Solution Approach 2:
The encapsulant material acts as an intermediary between the shielding layer and the semiconductor die. The shielding layer is formed in the trench and then encapsulant is disposed over it, creating a layered structure where the encapsulant mediates the interaction between the shielding layer and the die, providing both mechanical support and electromagnetic shielding.
2Reliability
If a trench is formed through the encapsulant and substrate, then shielding effectiveness is improved, but manufacturing complexity increases
Solution Approach 1:
The trench is formed through the encapsulant and substrate before the shielding layer is deposited. This preliminary action of creating the trench structure in advance allows the shielding material to be precisely positioned where it is most effective, improving shielding effectiveness while enabling a systematic manufacturing approach where subsequent steps follow a established pattern.
3Reliability
If the shielding layer extends through the trench into the substrate, then EMI and RFI isolation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The shielding layer is positioned locally within the trench structure, extending specifically into the substrate only where the trench provides a pathway. This localized positioning concentrates the shielding effect at the critical interface between encapsulant and substrate, improving EMI and RFI isolation while allowing manufacturing processes to focus precision on the trench formation rather than the entire shielding layer.
Data Source
AI summary
A semiconductor device has a plurality of conductive vias formed partially through a substrate. A conductive layer is formed over the substrate and electrically connected to the conductive vias. A semiconductor die is mounted over the substrate. An encapsulant is deposited over the semiconductor die and substrate. A trench is formed through the encapsulant around the semiconductor die. A shielding layer is formed over the encapsulant. The trench is formed partially through the substrate and the shielding layer is formed in the trench partially through the substrate. An insulating layer can be formed in the trench prior to forming the shielding layer. A portion of the substrate is removed to expose the conductive vias. An interconnect structure is formed over the substrate opposite the semiconductor die. The interconnect structure is electrically connected to the conductive vias. The shielding layer is electrically connected to the interconnect structure.