Dielectric Fin Gate Stack Layout for Isolation and Leakage Control
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, leading to issues with processing and manufacturing complexity.
Innovation Solution
The use of FinFET structures and gate-all-around (GAA) transistor structures, patterned using photolithography and self-aligned double-patterning or multi-patterning processes, which allow for the creation of smaller pitches and more complex patterns, along with the formation of dielectric fins and metal gate stacks to improve device performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are decreased to increase functional density, then production efficiency and cost are improved, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple discrete stages including forming first and second recesses at different depths, selective epitaxial growth in specific regions, and staged doping processes. This segmentation allows complex device formation to be broken down into manageable steps that can be executed with existing manufacturing capabilities while achieving advanced device geometries
Solution Approach 2:
The patent introduces vertical depth differentiation by forming first recesses extending to a first depth and second recesses extending to a second depth greater than the first depth. This multi-level recess structure enables complex device architectures to be created by utilizing the vertical dimension, thereby achieving high functional density without proportionally increasing lateral feature size reduction complexity
2Productivity
If feature sizes are decreased to increase functional density, then more interconnected devices per chip area are achieved, but manufacturing reliability decreases
Solution Approach 1:
Different regions of the substrate receive different treatments: first recesses are formed in first regions with specific epitaxial growth and doping, while second recesses in second regions receive different depth processing and doping concentrations. This local differentiation allows optimization of device performance and reliability in specific regions without compromising overall functional density
Solution Approach 2:
The patent implements staged doping processes where dopants are introduced at different stages of recess formation and epitaxial growth. This progressive doping approach ensures proper dopant distribution and activation before final device operation, thereby maintaining reliability even as device dimensions are reduced to increase functional density
3Manufacturing precision
If photolithography and self-aligned processes are used to pattern fins, then smaller and more complex circuits can be formed, but process steps and manufacturing complexity increase
Solution Approach 1:
Mask elements are formed beforehand to define the patterns of first and second recesses before any etching or growth operations. This preliminary patterning establishes a self-aligned framework that guides subsequent processing steps, enabling precise fin formation without requiring complex real-time alignment procedures
Solution Approach 2:
Epitaxial structures are grown as intermediary layers that fill the patterned recesses and provide a foundation for subsequent doping and device formation. These intermediary structures translate the patterned recess geometry into well-defined fin structures, simplifying the overall patterning process while achieving high manufacturing precision
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 enhances the performance and reliability of semiconductor devices by facilitating the formation of smaller, more complex structures, improving isolation and reducing leakage current, thus addressing the challenges of scaling down in semiconductor manufacturing.
Implementation Method 1
fins patterned using photolithography and self-aligned processes
Data Source
AI summary
A semiconductor device structure and a formation method are provided. The method includes forming a first dielectric fin and a second dielectric fin over a substrate, and the second dielectric fin is taller than the first dielectric fin. The method also includes forming a gate stack over the substrate, and the gate stack extends across the first dielectric fin and the second dielectric fin. The method further includes partially removing the gate stack such that an opening exposing the second dielectric fin is formed and forming an isolation structure in the opening.