Interlocking RF Shield Frame for IC Package Warpage Compensation
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Solution Overview
Problem
Warpage of integrated circuit package substrates leads to open solder joints and reduced effectiveness of RF shields in preventing electromagnetic interference, due to mismatched thermal expansion coefficients and large coplanarity issues between shield and substrate materials.
Innovation Solution
A warpage-compensating RF shield frame comprising multiple interlocking sections with interdigitating interface extensions that restrict lateral motion and articulate independently to follow substrate warpage, ensuring secure attachment and maintaining electrical coupling during thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid RF shield frame is used to ensure structural stability, then the shield can effectively contain RF energy, but the shield cannot accommodate substrate warpage, leading to broken solder joints
Solution Approach 1:
The RF shield frame is divided into multiple sections that can independently move relative to each other. Each section is attached to the substrate at specific locations, allowing the frame to flex and accommodate substrate warpage while maintaining continuous electrical connection to ground metallization throughout the shield structure.
Solution Approach 2:
The shield frame transitions from a rigid structure to a dynamic one where sections can move independently to follow substrate deformation. This dynamic capability allows the shield to maintain integrity during thermal cycling and warpage while preserving RF containment effectiveness.
2Reliability
If the shield frame is made flexible to accommodate warpage, then solder joint integrity is maintained, but the shield's ability to contain RF energy may be compromised
Solution Approach 1:
By segmenting the frame into multiple sections that move independently, the shield maintains overall structural integrity and continuous electrical connection to ground, preserving RF containment while allowing local flexibility to accommodate substrate warpage.
Solution Approach 2:
The shield frame's structural parameters are optimized to provide appropriate flexibility - sections are designed with specific attachment points and geometries that allow controlled movement to follow substrate deformation while maintaining sufficient rigidity to contain RF energy effectively.
3Adaptability or versatility
If multiple interlocking sections are used to compensate for warpage, then adaptability to substrate deformation is improved, but device complexity increases
Solution Approach 1:
The frame is segmented into multiple sections that are relatively simple in individual design but collectively provide warpage compensation through their interlocking arrangement. Each section attaches to the substrate and connects to adjacent sections, creating a modular system that adapts to deformation.
Solution Approach 2:
Multiple simple frame sections are combined into an integrated shield assembly where each section performs dual functions: providing structural support and enabling relative movement to accommodate warpage. The interlocking design merges simplicity of individual components with complexity of collective adaptability.
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 mitigates warpage-induced solder joint failures, maintaining RF shield integrity and reducing electromagnetic interference, while adhering to package height and cost constraints.
Implementation Method 1
mismatched thermal expansion coefficients and large coplanarity issues between shield and substrate materials
Data Source
AI summary
An integrated circuit package shield comprising a frame comprising two or more segments, the segments to interlock with one another along a substrate and the segments comprising electrically conductive material to electrically couple to the substrate; and a lid to cover the frame, the lid comprising a conductive material to electrically couple to the substrate.