Conformal RF Shielding Using Wire-Bonds in BGA Arrays
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Solution Overview
Problem
Conventional RF shielding methods, such as those using ball grid arrays (BGA), face challenges in miniaturized electrical circuits due to increased component density, requiring more efficient and cost-effective solutions for RF and EMI shielding.
Innovation Solution
The use of wire-bonds as an alternative to BGA balls for RF shielding, which provide improved RF signal and domain barrier isolation, are more area-efficient, and can make contact with the printed circuit board to enhance RF isolation, allowing for higher IC integration and reduced module size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional BGA shielding is used, then RF shielding is provided, but component density increases and available real estate decreases
Solution Approach 1:
The patent merges the shielding function with the existing BGA ball array structure by configuring selected solder balls as shielding elements that are electrically connected to ground, eliminating the need for separate shielding components and reducing overall component count and space requirements
Solution Approach 2:
The BGA balls serve dual functions: providing electrical connections for the integrated circuit and simultaneously providing RF shielding when configured as ground connections, thereby maximizing the utility of existing components without requiring additional real estate
2Object-affected harmful factors
If pre-tinned tabs are used for shielding, then shielding is provided, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent extracts the shielding function from separate physical components (tabs, shields) and integrates it directly into the existing BGA ball array structure, simplifying the overall device architecture by eliminating redundant shielding elements and their associated mounting hardware
Solution Approach 2:
The BGA ball array inherently provides both electrical connection and shielding functions through proper configuration, allowing the structure to serve itself without requiring additional shielding components, tabs, or complex assembly procedures
3Object-affected harmful factors
If conventional shielding techniques are used, then RF shielding is achieved, but manufacturing cost and process time increase
Solution Approach 1:
The patent combines the shielding function with the standard BGA mounting process, allowing shielding to be achieved through the existing solder ball placement and grounding procedures without requiring separate manufacturing steps, additional materials, or specialized assembly processes
Data Source
AI summary
An RF/EMI shield has a substrate, a plurality of solder balls on a first side of the substrate, and a plurality of wire-bonds on a periphery of the first side of the substrate to form a shield which can be soldered in a surface mount process directly around components needing shielding. Each of the plurality of wire-bonds has a width selected as a fraction of the wavelength of interest.