Backside Contact Layout for Uniform Substrate Voltage in ESD Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices face challenges in ensuring simultaneous triggering of all fingers during electrostatic discharge events, leading to non-uniform voltage distribution and potential damage due to uneven current distribution.
Innovation Solution
The implementation of backside contacts in semiconductor devices to control substrate voltage, ensuring uniform potential across all fingers, facilitating simultaneous triggering and even current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional substrate voltage control is used, then device structure is simple, but voltage distribution is non-uniform leading to unreliable ESD protection
Solution Approach 1:
The substrate voltage control is segmented into multiple independent backside contacts (first backside contact, second backside contact, third backside contact) that can be independently controlled. Each contact connects to different well regions (first N-type well, second N-type well, P-type well) allowing localized voltage control across different fingers, ensuring uniform voltage distribution and simultaneous triggering for reliable ESD protection.
Solution Approach 2:
The invention implements equipotentiality by connecting multiple substrate regions to a common reference potential through the backside contacts and metal line structure. The first and second backside contacts connect to N-type wells while the third connects to the P-type well, all referenced to ground or bias potential, ensuring uniform substrate potential across all fingers during ESD events for synchronized operation.
2Manufacturing precision
If backside contacts are added to control substrate voltage, then voltage distribution becomes uniform, but device structure becomes more complex
Solution Approach 1:
Multiple backside contacts (first, second, and third backside contacts) are merged into a unified voltage control system through metal lines that connect them to respective well regions and the interlayer dielectric structure. This combining approach achieves uniform substrate potential across all fingers while managing structural complexity through integrated metallization and insulation layers.
Solution Approach 2:
The interlayer dielectric and metal line structure serve as intermediaries between the backside contacts and the well regions. These intermediary layers enable precise voltage control and uniform potential distribution across the substrate without requiring direct complex connections, simplifying the overall structure while achieving manufacturing precision.
3Reliability
If multiple backside contacts are used, then simultaneous triggering is achieved, but fabrication process becomes more difficult
Solution Approach 1:
The backside contact structure serves multiple functions simultaneously: it provides voltage control, electrical connection to wells, and substrate potential reference. The metal lines and interlayer dielectric structure also serve dual purposes of electrical interconnection and mechanical support, reducing the need for separate structures and simplifying the overall fabrication process despite the multiple contacts required for synchronous triggering.
Data Source
AI summary
A semiconductor device includes a passive device includes a plurality of emitters, a plurality of collectors, a plurality of bases, a plurality of backside contacts connecting the plurality of bases to a backside of the semiconductor device. The plurality of bases are connected to each other via the plurality of backside contacts and a metal line on a backside of the semiconductor device.