Fin-Based ESD Protection Structure for Isolated Current Paths
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Solution Overview
Problem
As integrated circuits (ICs) miniaturize, they become more susceptible to electrostatic discharge (ESD) damage due to increased functional density and decreased geometric size, necessitating effective ESD protection structures to prevent internal circuit damage from excess charge transmission.
Innovation Solution
The proposed ESD protection structure incorporates fin-based ESD diodes with P-type and N-type well regions and metal lines, where ESD current flows through P-type and N-type fins in sequence, preventing damage by isolating the current from other devices and increasing the turn-on voltage of the ESD protection network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ICs are miniaturized with increased functional density, then integration capacity and processing power are improved, but susceptibility to ESD damage increases
Solution Approach 1:
The ESD protection structure is segmented into multiple discrete components: P-type fins, N-type fins, P-type well regions, and N-type well regions arranged in alternating groups. This segmentation allows each component to perform its specific function in the ESD current path while maintaining overall protection effectiveness in miniaturized IC structures.
Solution Approach 2:
The P-type and N-type well regions act as intermediary structures between the P-type substrate and the ESD current path. These well regions provide controlled pathways for ESD current while isolating it from sensitive circuit devices, thereby mediating between the harmful ESD event and the protected IC components.
2Reliability
If ESD current is isolated from other devices, then damage to functional circuits is prevented, but the ESD protection network complexity increases
Solution Approach 1:
The ESD protection structure merges multiple protective elements (P-type fins, N-type fins, P-type well regions, N-type well regions) into a single integrated network that operates as a unified system. This merging provides comprehensive ESD protection while sharing common structural elements and fabrication processes, thereby reducing overall complexity compared to multiple separate protection structures.
Solution Approach 2:
The alternating P-type and N-type fin and well region structures serve multiple functions: they provide ESD current isolation, establish controlled current paths, increase turn-on voltage through series PN junctions, and protect multiple types of circuits simultaneously. This multi-functionality reduces the need for separate specialized protection structures for different circuits.
3Reliability
If the turn-on voltage of the ESD protection network is increased, then false triggering is reduced, but the protection response time may be delayed
Solution Approach 1:
The turn-on voltage of the ESD protection network is increased by changing the structural parameters: adding multiple PN junctions in series through alternating P-type and N-type fin and well region groups. This parameter change raises the threshold voltage to prevent false triggering while the distributed structure maintains adequate response speed by providing multiple parallel current paths.
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 configuration effectively protects ICs from ESD by isolating the ESD current and increasing the turn-on voltage, thereby preventing damage to other devices and enhancing the ESD protection network's efficiency.
Implementation Method 1
When an ESD event is present, an ESD current flows from the first metal lines to the second metal line through the P-type fins, the first P-type well region and the N-type fins in sequence
Data Source
AI summary
Electrostatic discharge (ESD) protection structures are provided. A first N-type well region is formed over a P-type semiconductor substrate. First P-type well region and second N-type well region are formed over the first N-type well region. A plurality of first device areas are formed over the first P-type well region. Each first device area includes a plurality of P-type fins extending in a first direction. The P-type fins are divided into a plurality of first groups in each of the first device areas. A second device area is formed over the first P-type well region, and includes a plurality of N-type fins extending in the first direction and surrounded by the first device areas. When an ESD event is present, an ESD current flows sequentially through the P-type fins, the first P-type well region and the N-type fins.