RFIC Crackstop With Embedded Passive Filters for RF Noise Isolation
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Solution Overview
Problem
Radio frequency integrated circuit (RFIC) chips face interference from metallic barriers used as crackstops, which propagate RF noise signals and also allow moisture ingress, compromising device operation and reliability.
Innovation Solution
Incorporating embedded noise suppressors, such as passive filters (low pass, high pass, band pass, and band stop filters) within the metallic barriers of the crackstop to inhibit RF noise signal propagation while maintaining moisture protection, using electromagnetic devices like resistors, inductors, and capacitors strategically placed to isolate specific RF ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic barrier (crackstop) is used to protect the IC area, then mechanical strength and moisture protection are improved, but RF noise signal propagation increases
Solution Approach 1:
The crackstop structure is modified by introducing localized non-conductive material regions (gaps) at specific positions where via bars intersect. This creates different electrical properties at different locations of the metallic barrier, allowing RF noise blocking at critical points while maintaining overall structural integrity and moisture protection.
Solution Approach 2:
The crackstop transitions from a purely metallic continuous structure to a composite structure combining conductive via bars with non-conductive gap regions. This composite approach enables the structure to simultaneously provide mechanical support, moisture barrier functions, and RF noise suppression at specific frequencies.
2Reliability
If the metallic barrier is made continuous to improve moisture protection, then reliability against moisture ingress is improved, but RF noise coupling between devices increases
Solution Approach 1:
Instead of making the entire metallic barrier discontinuous, the invention introduces localized non-conductive gaps only at specific via bar intersections. This maintains continuous moisture protection through the metallic structure while creating localized RF noise blocking points where needed.
Solution Approach 2:
Non-conductive material regions are introduced as intermediary elements between the conductive via bars. These intermediary regions act as RF noise barriers while allowing the metallic barrier to remain continuous for moisture protection, effectively mediating between the two conflicting requirements.
3Object-generated harmful factors
If gaps are introduced in the metallic barrier to block RF noise, then RF noise propagation is reduced, but moisture protection capability deteriorates
Solution Approach 1:
The non-conductive gaps are introduced only at specific localized positions (via bar intersections) rather than throughout the entire metallic barrier. This provides RF noise blocking at critical points while maintaining continuous moisture protection through the rest of the metallic structure.
Solution Approach 2:
Instead of making the entire metallic barrier discontinuous to block RF noise, the invention applies partial action by introducing gaps only where via bars intersect. This partial discontinuity is sufficient to block RF noise propagation while maintaining overall moisture barrier integrity.
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
Effectively minimizes local signal interference and prevents moisture ingress, ensuring reliable operation of RFIC chips by isolating specific RF noise signals and maintaining the integrity of the crackstop's moisture barrier.
Implementation Method 1
One or more noise suppressors and, particularly, one or more passive filters (e.g., low pass filter(s), high pass filter(s), band pass filter(s), and/or band stop filter(s)) can be integrated into and, if applicable, between the structure of the metallic barrier(s) in order to inhibit propagation, through the crackstop, of noise signals within a specific RF range.
Implementation Method 2
The electromagnetic device(s) can be embedded in the metallic barrier.
Implementation Method 3
at least one integrated passive filter (e.g., low pass filter(s), high pass filter(s), band pass filter(s) and/or band stop filter(s)) that includes at least one electromagnetic device (e.g., a resistor, an inductor, a capacitor, and/or a stub)
Data Source
AI summary
Disclosed is a radio frequency integrated circuit (RFIC) chip that includes an integrated circuit (IC) area and a crackstop laterally surrounding the IC area. The crackstop includes a metallic barrier (or, alternatively, concentric metallic barriers) electrically isolated from the IC area. One or more noise suppressors and, particularly, one or more passive filters (e.g., low pass filter(s), high pass filter(s), band pass filter(s), and/or band stop filter(s)) are integrated into the structure of the metallic barrier(s) to inhibit propagation, through the crackstop, of noise signals within a specific RF range. The specific RF range can be a customer-specified operating parameter. By embedding customized noise suppressor(s) into the crackstop, local signal interference unique to the customer-specified operating parameters can be minimized while also avoiding or at least minimizing the risk of moisture ingress to the IC area. Also disclosed is a method of forming the chip.