Wire Bond Shielding Structure for Low-Profile Package EMI Control
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Solution Overview
Problem
Conventional electromagnetic interference (EMI) shielding technologies are cumbersome, expensive, and unsuitable for low-profile or stacked die applications, particularly in mobile devices and 3D ICs, where they fail to effectively suppress EMI emissions and enhance electromagnetic compatibility (EMC).
Innovation Solution
The use of wire bond wires with specific pitches and shapes to form interference shielding cages, coupled with a conductive layer for electrical conductivity, creates a fence-like perimeter that effectively suppresses EMI by spacing wire bond wires closer than electromagnetic wavelengths, thereby reducing EMI emissions and enhancing EMC in microelectronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional EMI shielding materials and structures are used, then EMI suppression is achieved, but device weight increases and profile height increases
Solution Approach 1:
The patent uses wire bond wires arranged in specific patterns to form a lightweight shielding structure that functions as a thin film or cage, replacing conventional heavy EMI shielding materials while maintaining EMI suppression effectiveness
Solution Approach 2:
The shielding structure is segmented into multiple wire bond wires arranged in patterns (such as picket fence, meander, or spiral patterns) rather than using a solid shielding material, reducing weight while maintaining EMI suppression through the distributed wire configuration
2Object-affected harmful factors
If conventional EMI shielding structures are used, then EMI suppression is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The wire bond wires serve dual functions: providing electrical interconnections between die and package and simultaneously forming EMI shielding structures, eliminating the need for separate shielding components and reducing manufacturing complexity
Solution Approach 2:
The EMI shielding function is merged with the existing wire bond interconnect structure, combining two functions (electrical connection and EMI shielding) into a single integrated system that reduces overall device complexity
3Object-affected harmful factors
If conventional EMI shielding is used in stacked die applications, then EMI suppression is attempted, but the shielding is too large for low-profile applications
Solution Approach 1:
The wire bond wires are arranged in three-dimensional patterns (such as vertical walls, spirals, or meander patterns) that provide EMI shielding in multiple dimensions with minimal volume, enabling effective shielding in compact stacked die configurations
4Object-affected harmful factors
If wire bond wires are spaced closer to reduce EMI emissions, then EMI suppression improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes wire bond wire pitch parameters within standard manufacturing capabilities, selecting specific pitch values and patterns that achieve effective EMI suppression while remaining compatible with existing wire bonding process precision
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 approach achieves significant EMI suppression, with up to 33 dB of EMI reduction at specific frequencies, and can enhance EMC in devices like mobile phones and Internet of Things devices, making it suitable for compact and high-frequency applications.
Implementation Method 1
The wire bond wires are spaced apart from one another to provide a fence-like perimeter with spacings between each pair of adjacent wire bond wires being smaller than electrical wavelengths, thereby reducing EMI emissions
Data Source
AI summary
Apparatuses relating generally to a microelectronic package having protection from electromagnetic interference are disclosed. In an apparatus thereof, a platform has an upper surface and a lower surface opposite the upper surface and has a ground plane. A microelectronic device is coupled to the upper surface of the platform. Wire bond wires are coupled to the ground plane with a pitch. The wire bond wires extend away from the upper surface of the platform with upper ends of the wire bond wires extending above an upper surface of the microelectronic device. The wire bond wires are spaced apart from one another to provide a fence-like perimeter to provide an interference shielding cage. A conductive layer is coupled to at least a subset of the upper ends of the wire bond wires for electrical conductivity to provide a conductive shielding layer to cover the interference shielding cage.