Semiconductor Guard Ring Segmentation for Noise Isolation
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Solution Overview
Problem
Noise transmission through a guard ring in semiconductor devices, such as a seal ring, can cause malfunctions in adjacent device regions, particularly between logic and analog circuit units.
Innovation Solution
A nonconducting part is formed in the guard ring forming region to block electric conduction between device regions, using insulating regions or pn junction planes to increase impedance and prevent noise transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous guard ring is formed to protect the circuit-forming region from moisture and cracks, then the protective function is improved, but noise transmission between device regions occurs causing malfunctions
Solution Approach 1:
The continuous guard ring is divided into multiple discrete guard ring portions by introducing nonconducting parts (insulating regions or pn junction planes) at specific locations. This segmentation maintains the protective function against moisture and cracks while blocking noise transmission paths between logic and analog circuit units, as the discontinuous structure interrupts electrical conduction between device regions.
Solution Approach 2:
Different regions of the guard ring structure are given different electrical properties: most portions remain conductive for protection, while specific localized portions are made nonconducting (through insulating regions or pn junctions) to block noise. This local differentiation allows the guard ring to simultaneously provide protective coverage and noise isolation where needed.
2Reliability
If a seal ring is formed using conductive materials to protect against external atmosphere, then the sealing function is improved, but electric conduction between device regions causes noise interference
Solution Approach 1:
The seal ring structure is segmented into multiple conductive portions separated by nonconducting parts. This allows the seal ring to maintain its protective sealing function while the nonconducting portions interrupt electrical conduction paths, preventing noise interference between adjacent device regions such as logic and analog circuits.
Solution Approach 2:
Nonconducting parts (insulating regions or pn junction planes) are introduced as intermediary elements within the seal ring structure. These intermediaries physically connect or support the conductive portions while electrically isolating them, enabling the seal ring to provide both mechanical protection and electrical isolation functions simultaneously.
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 prevents noise transmission between device regions, ensuring reliable operation of semiconductor devices with both digital and analog circuits by increasing impedance and reducing capacity in the conduction path.
Implementation Method 1
A nonconducting part blocking electric conduction in a path from the first device region, through the guard ring to the second device region is formed in a guard ring forming region
Data Source
AI summary
A semiconductor chip 100 includes a logic unit and an analog unit 153. Furthermore, the semiconductor chip 100 includes a silicon substrate 101; a first insulating film 123 to a sixth insulating film 143 formed on the silicon substrate 101; and an annular seal ring 105 consisting of a first conductive ring 125 to a sixth conductive ring 145 buried in the first insulating film 123 to the sixth insulating film 143, which surrounds the periphery of the logic unit and the analog unit 153. In the seal ring region 106, there is formed a pn junction acting as a nonconducting part 104, which blocks conduction in a path from the logic unit, through the seal ring 105 to the analog unit 153.