Shielding Layer Grounded via Metal Pillars in Semiconductor Substrates
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Solution Overview
Problem
Existing semiconductor devices face challenges in effectively isolating from electromagnetic interference (EMI) and radio frequency interference (RFI) due to the need for thicker substrates and additional production steps, such as plating processes, to connect shielding layers to ground planes.
Innovation Solution
A method involving the formation of metal pillars through a substrate in a peripheral region around semiconductor die to electrically connect a top shielding layer to a ground plane, simplifying the interconnect and potentially reducing substrate thickness without altering the circuit design or embedding a ground plane in the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shielding layer is connected to a ground plane using conventional methods, then EMI and RFI isolation is improved, but substrate thickness must be increased and manufacturing complexity increases due to plating processes
Solution Approach 1:
The invention extracts the ground connection function from the substrate interior by forming openings through the substrate that allow the shielding layer to contact external ground points directly. This removes the need for embedded ground planes within the substrate thickness, thereby reducing substrate thickness while maintaining EMI/RFI isolation effectiveness.
Solution Approach 2:
The invention performs preliminary actions by forming openings and applying conductive material to the shielding layer before final assembly. The openings are formed through the substrate and the shielding layer is positioned and connected to ground points in advance, simplifying the overall manufacturing process by eliminating subsequent plating steps.
2Object-affected harmful factors
If a shielding layer is connected to a ground plane using plating processes, then EMI and RFI isolation is improved, but manufacturing complexity and costs increase due to additional production steps
Solution Approach 1:
The invention extracts the complex plating process from the manufacturing sequence by using pre-formed conductive elements or simple conductive coatings applied to the shielding layer before assembly. This removes the need for post-assembly plating operations, thereby reducing manufacturing complexity and costs while maintaining effective EMI/RFI isolation.
Solution Approach 2:
The shielding layer is equipped with self-contained conductive properties through preliminary coating or material selection, allowing it to establish ground connections without requiring external plating processes. The shielding layer essentially serves itself by having the necessary conductive characteristics built-in before assembly.
3Volume of moving object
If the substrate is made thinner to reduce package size, then device density is improved, but the risk of substrate breakage increases
Solution Approach 1:
The invention extracts the ground plane function from the substrate structure, allowing the substrate to be thinner since it no longer needs to accommodate embedded ground planes. The ground connections are established through external pathways, reducing the structural demands on the substrate and thereby reducing breakage risk despite reduced thickness.
4Object-affected harmful factors
If metal pillars are formed through the substrate to connect shielding layer to ground plane, then EMI and RFI isolation is improved, but manufacturing complexity increases due to additional formation steps
Solution Approach 1:
The invention merges the formation of metal pillars with existing substrate processing steps, such as forming openings during the same manufacturing sequence that creates other interconnect structures. By combining these operations, the additional complexity is minimized and the overall manufacturing process remains efficient while achieving effective EMI/RFI isolation.
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 solution provides effective isolation from EMI and RFI while maintaining substrate integrity and reducing manufacturing complexity and costs by establishing a direct electrical connection between the shielding layer and the ground plane using metal pillars, allowing for thinner packages without additional conductive elements.
Implementation Method 1
forming a metal pillar in the opening to electrically connect the shielding layer to a ground plane in the second substrate
Data Source
AI summary
A shielded semiconductor device is made by mounting semiconductor die to a first substrate. An encapsulant is formed over the semiconductor die and first substrate. A dicing channel is formed through the encapsulant between the semiconductor die. A hole is drilled in the first substrate along the dicing channel on each side of the semiconductor die. A shielding layer is formed over the encapsulant and semiconductor die. The hole is lined with the shielding layer. The first substrate is singulated to separate the semiconductor die. The first substrate is mounted to a second substrate. A metal pillar is formed in the opening to electrically connect the shielding layer to a ground plane in the second substrate. The metal pillar includes a hook for a mechanically secure connection to the shielding layer. An interconnect structure is formed on the first substrate to electrically connect the semiconductor die to the second substrate.