Interconnect Shielding Layer With Cavities for Crosstalk Isolation
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Solution Overview
Problem
Tightly coupled first level interconnects in semiconductor devices experience signal integrity degradation due to electromagnetic interference and crosstalk, limiting input/output data-rate and silicon area performance scaling.
Innovation Solution
A conductive layer with cavities and a dielectric layer is introduced to isolate electromagnetic coupling between interconnects, providing improved signal integrity by acting as a shield and reducing crosstalk, particularly at pitches of 110 μm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If first level interconnects are tightly coupled to increase I/O density, then silicon area performance is improved, but signal integrity degradation due to crosstalk increases
Solution Approach 1:
A conductive shielding layer is introduced as an intermediary element between adjacent interconnects. This shielding layer acts as a mediator that blocks electromagnetic fields and crosstalk while allowing the interconnects to remain tightly coupled, thus maintaining high I/O density without sacrificing signal integrity
Solution Approach 2:
The solution moves from a two-dimensional planar arrangement of interconnects to a three-dimensional structure by adding a conductive shielding layer in the vertical dimension. This allows tight horizontal coupling for high density while providing vertical shielding for signal integrity protection
2Area of stationary object
If space between interconnects is reduced to increase I/O density, then silicon footprint is reduced, but electromagnetic interference and crosstalk increase
Solution Approach 1:
The conductive shielding layer serves as a protective intermediary positioned between interconnects with reduced spacing. It blocks electromagnetic interference and crosstalk that would otherwise affect the tightly spaced interconnects, enabling high I/O density without compromising signal quality
Solution Approach 2:
A thin conductive shielding film is applied between interconnects to provide electromagnetic protection. This thin film structure allows maintaining small interconnect spacing while effectively blocking harmful electromagnetic interference and crosstalk
3Reliability
If conductive shielding layer is added to reduce crosstalk, then signal integrity is improved, but device complexity increases
Solution Approach 1:
The conductive shielding layer performs multiple functions simultaneously: it shields against crosstalk, provides a reference plane for signal routing, and can serve as an additional signal layer. This multi-functionality reduces the need for separate shielding structures, thereby limiting the increase in device complexity
4Object-affected harmful factors
If conductive layer with cavities is used to isolate electromagnetic coupling, then crosstalk is reduced, but manufacturing complexity increases
Solution Approach 1:
The conductive shielding layer is segmented into regions with cavities or openings positioned over signal vias. This segmentation allows electromagnetic isolation between adjacent interconnects while maintaining manufacturing feasibility through standard PCB fabrication processes that can create such patterned conductive layers
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 enhances electrical performance by mitigating signal degradation, improving data bandwidth, and reducing package warpage, while allowing for smaller silicon footprints and increased I/O density.
Implementation Method 1
A conductive layer with cavities and a dielectric layer is introduced to isolate electromagnetic coupling between interconnects, providing improved signal integrity by acting as a shield and reducing crosstalk
Implementation Method 2
A conductive layer with cavities and a dielectric layer is introduced to isolate electromagnetic coupling between interconnects
Data Source
AI summary
The technique described herein includes a device to address the electrical performance (e.g. signal integrity) degradation ascribed to electromagnetic interference and/or crosstalk coupling occur at tightly coupled (e.g. about 110 μm pitch or less) interconnects, including the first level (e.g. the interconnection between a die and a package substrate). In some embodiments, this invention provides a conductive layer with a plurality of cavities to isolate electromagnetic coupling and/or interference between adjacent interconnects for electronic device performance scaling. In some embodiments, at least one interconnect joint is coupled to the conductive layer, and at least one interconnect joint is isolated from the conductive layer by a dielectric lining at least one of the cavities, the conductive layer being associated to a ground reference voltage by the interconnect joint coupled to the conductive layer.