Fin-Insulating Structure in CPODE to Prevent Contact Bridging
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Solution Overview
Problem
Existing techniques for scaling contacted poly pitch (CPP) in semiconductor manufacturing, such as the continuous poly on diffusion edge (CPODE) process, face challenges like short circuits due to bridging of adjacent source/drain contacts during etching, which degrades device performance and reliability.
Innovation Solution
A method involving a CPODE process with a fin-insulating structure formed using a dry etching process and filled with dielectric material like silicon nitride to isolate neighboring active regions, ensuring precise trench formation and refill to prevent contact bridging, allowing for continued scaling while maintaining gate control and reducing short-channel effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CPODE process is used to scale contacted poly pitch (CPP), then gate control and device density are improved, but adjacent source/drain contacts may bridge during etching causing short circuits
Solution Approach 1:
The patent segments the trench structure into two distinct portions: a first portion extending from the fin top to a first depth, and a second portion extending from the first depth to a second depth. This segmentation allows different materials and properties to be applied to different regions, preventing contact bridging while maintaining scaling benefits.
Solution Approach 2:
The patent applies different materials to different portions of the trench: a first material in the first portion and a second material in the second portion. This local differentiation provides targeted protection where needed - the first material prevents bridging at the critical fin region, while the second material provides additional isolation deeper in the substrate.
2Reliability
If continuous poly on diffusion edge (CPODE) structure is formed to isolate fin regions, then neighboring active regions are isolated, but manufacturing complexity increases
Solution Approach 1:
The trench is divided into two depth portions, each filled with different materials. This segmentation achieves reliable isolation of active regions while the systematic approach to filling (sequential deposition into defined depth regions) keeps the manufacturing process manageable and scalable.
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 approach effectively isolates neighboring active regions, preventing short circuits and enhancing device reliability and performance by maintaining gate control and reducing short-channel effects, thus enabling further scaling and increased density in multi-gate devices.
Implementation Method 1
a trench is formed in the fin using a dry etching process
Data Source
AI summary
A semiconductor device includes a silicon substrate and a fin formed above the substrate. The fin provides active regions for two devices, such as gate-all-around transistors. The semiconductor device also includes a fin-insulating structure positioned to electrically isolate the active regions for the two devices. The fin-insulating structure is formed in a trench, with a first portion adjacent the fin and a second portion below the fin and extending into the substrate. The fin-insulating structure includes an oxide liner in the second portion of the trench, but not the first portion. The fin-insulating structure is further filled with an insulating material such as silicon nitride.