Peripheral Gate Structure With U-Shaped Dielectric for Simpler Fabrication
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Solution Overview
Problem
Challenges arise during the scaling-down process of semiconductor devices in achieving improved quality, yield, performance, and reliability while reducing complexity, particularly in forming peripheral and array gate structures.
Innovation Solution
A semiconductor device design featuring a peripheral gate structure with a U-shaped cross-sectional profile, including a peripheral gate dielectric layer, a peripheral gate conductor, and a peripheral gate capping layer, which are formed using a dummy filler layer to simplify fabrication, reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional fabrication methods are used for both peripheral and array gate structures, then manufacturing precision may be maintained, but device complexity and fabrication cost increase
Solution Approach 1:
The patent merges the fabrication processes for peripheral and array gate structures into a unified flow. The peripheral gate structure is formed using the same trench formation, filler deposition, and patterning steps as the array gate structures, eliminating separate processing sequences and reducing overall fabrication complexity while maintaining precision through consistent process application
Solution Approach 2:
The invention creates a universal fabrication approach where the peripheral gate structure serves multiple functions: it provides device isolation, defines peripheral circuit regions, and integrates with array gate structures through common process steps. The dummy filler layer and gate capping layer serve both structural and process alignment functions across different device regions
2Ease of manufacture
If separate fabrication processes are used for peripheral and array gate structures, then manufacturing precision may be maintained, but fabrication cost increases
Solution Approach 1:
The patent combines peripheral and array gate fabrication into a single integrated process flow, using common steps for trench formation, filler material deposition, and gate conductor patterning. This merging eliminates redundant processing and material usage, directly reducing fabrication cost while maintaining precision through consistent process parameters applied across all gate structures
Solution Approach 2:
The invention employs preliminary actions by forming a dummy filler layer in peripheral trenches before array gate processing, and using a gate capping layer that is deposited early to establish a common reference plane. These preliminary structures enable subsequent precise patterning and alignment of both peripheral and array gates using the same lithography and etching steps
Data Source
AI summary
The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a substrate including an array area and a peripheral area; and a peripheral gate structure including: a peripheral gate dielectric layer inwardly positioned in the peripheral area of the substrate and including a U-shaped cross-sectional profile; a peripheral gate conductor including a bottom portion positioned on the peripheral gate dielectric layer and a neck portion positioned on the bottom portion; and a peripheral gate capping layer positioned on the peripheral gate dielectric layer and the bottom portion, and surrounding the neck portion. A top surface of the peripheral gate capping layer and a top surface of the neck portion are substantially coplanar.