Semiconductor Package EMI Shielding for Fine-Pitch Wire Stability
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Solution Overview
Problem
Conventional wire bonding in semiconductor packaging leads to bonding wire sweep during encapsulation, causing shorting due to increased density of input/output terminal pads, and existing solutions require additional process steps or specialized equipment, while also failing to effectively address electromagnetic interference (EMI) and electrostatic discharge (ESD) issues.
Innovation Solution
A semiconductor package design featuring stabilized, insulator-coated bonding wires and a package-level EMI shielding structure, which includes a metal layer and grounded second bonding wires forming a Faraday cage to shield against EMI, and an insulating material that secures the wires and prevents deformation during encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of I/O terminal pads is increased to provide higher density IC packages, then the packaging capacity is improved, but the pitch between adjacent bonding wires becomes finer which causes bonding wire sweep and shorting during encapsulation
Solution Approach 1:
The bonding wires are coated with insulating material before the encapsulation process to prevent wire sweep and shorting during molding. This preliminary protective action ensures wire stability is maintained even as I/O pad density increases
Solution Approach 2:
An insulating material is introduced as an intermediary layer between adjacent bonding wires to prevent electrical shorting while allowing the wires to remain in close proximity for high-density packaging
2Productivity
If conventional wire bonding technique is used to increase I/O terminal pads, then the packaging density is improved, but bonding wire sweep occurs during encapsulation causing shorting between adjacent wires
Solution Approach 1:
The physical and chemical properties of the bonding wires are modified by coating them with insulating material, changing their surface characteristics to prevent deformation during encapsulation while maintaining positioning accuracy
Solution Approach 2:
The bonding wire structure is transformed into a composite material system consisting of conductive wire core and insulating coating layer, combining electrical conductivity with mechanical stability and deformation resistance
3Reliability
If additional process steps or specialized equipment are used to reduce bonding wire sweep, then the wire stability is improved, but the production cost increases
Solution Approach 1:
The insulating coating application is merged with the existing encapsulation process flow, eliminating the need for separate specialized equipment or additional process steps while achieving wire stability
Solution Approach 2:
The insulating material serves multiple functions simultaneously: it prevents wire sweep, provides electrical insulation, and integrates with the encapsulation process, allowing the system to serve itself without additional manufacturing complexity
4Quantity of substance
If the pitch between bonding wires is reduced to accommodate more I/O pads, then the packaging capacity is improved, but the probability of wire shorting during encapsulation increases
Solution Approach 1:
The insulating coating acts as an intermediary barrier between adjacent bonding wires, providing electrical isolation that prevents EMI and ESD while allowing the wires to be positioned closer together for higher density packaging
Solution Approach 2:
The insulating material is applied locally to the bonding wire surfaces where electrical isolation is most critical, providing targeted protection against EMI and ESD at the wire interfaces without affecting overall package 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 solution effectively prevents wire shorting, reduces EMI and ESD risks, and maintains package quality without adding costly process steps or equipment, enhancing the reliability of semiconductor packages.
Implementation Method 1
The metal layer and the plurality of second bonding wires constitute an electromagnetic interference (EMI) shielding structure
Implementation Method 2
an insulating material encapsulating the plurality of first bonding wires
Data Source
AI summary
A semiconductor package includes a carrier substrate having a top surface; a semiconductor die mounted on the top surface; first bonding wires connecting the semiconductor die to the carrier substrate; an insulating material encapsulating the plurality of first bonding wires; a component having a metal layer mounted on the insulating material; second bonding wires connecting the metal layer of the component to the carrier substrate; and a molding compound covering the top surface of the carrier substrate and encapsulating the semiconductor die, the component, the first bonding wires, the second bonding wires, and the insulating material. The metal layer and the second bonding wires constitute an electromagnetic interference (EMI) shielding structure.