RFIC Crackstop with Embedded Passive Filtering for RF Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radio frequency integrated circuit (RFIC) chips face interference issues due to the propagation of RF noise signals through metallic barriers known as crackstops, which also pose a risk of moisture ingress, compromising the integrity and performance of the ICs during dicing and packaging.
Innovation Solution
Incorporating embedded noise suppressors, specifically passive filters like low pass, high pass, band pass, and band stop filters, into the crackstop structure to inhibit the propagation of RF noise signals within a specific frequency range, while maintaining the barrier's functionality to prevent moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic barrier (crackstop) is used to protect the IC area, then mechanical protection and moisture ingress prevention are improved, but RF noise signal propagation increases
Solution Approach 1:
The crackstop structure is designed with non-uniform characteristics by introducing gaps or discontinuities at specific locations along the metallic barrier. These localized modifications create frequency-selective filtering properties that allow the crackstop to block RF noise signals within specific frequency ranges while maintaining mechanical integrity and moisture protection throughout the entire structure.
Solution Approach 2:
The crackstop employs a composite structure combining metallic barrier material with dielectric or conductive gap regions. This composite design enables the structure to simultaneously provide mechanical strength, moisture blocking, and RF noise filtering by leveraging the different electromagnetic properties of the constituent materials and their spatial arrangement.
2Object-affected harmful factors
If a continuous metallic barrier is used, then moisture ingress prevention is improved, but RF noise blocking capability worsens
Solution Approach 1:
The continuous metallic barrier is segmented into discrete sections separated by gaps or discontinuities. This segmentation disrupts the propagation path of RF noise signals while the gaps are designed and positioned to maintain the barrier's continuity for moisture prevention, effectively decoupling the mechanical protection function from the electromagnetic shielding function.
3Object-generated harmful factors
If the crackstop is modified to reduce RF noise propagation, then RF noise blocking is improved, but manufacturing complexity increases
Solution Approach 1:
The crackstop design modifies geometric parameters such as gap width, gap spacing, and metallic barrier thickness to achieve frequency-selective noise filtering. By carefully selecting these parameters, the structure achieves effective RF noise blocking without requiring complex multi-layer configurations or additional components, maintaining manufacturing simplicity while achieving the desired electromagnetic filtering performance.
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 the operational integrity of RFIC chips by selectively filtering out noise signals and maintaining the protective barrier around the IC area.
Implementation Method 1
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)
Implementation Method 2
The passive filter can be configured to inhibit propagation, through the crackstop, of noise signals within a specific RF range
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.