GAA IC Structure With Backside Via Routing Through Gate Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in fabricating gate-all-around (GAA) transistors due to limitations in patterning and etching processes, which affect the formation of multi-gate devices with precise control over nanoscale dimensions and materials, leading to inefficiencies in device performance and density.
Innovation Solution
A method for fabricating integrated circuit structures involving the formation of nanosheet channels using epitaxial layers, with selective etching and replacement of dummy gate structures with high-k/metal gate structures, and the use of conductive vias for efficient signal routing, allowing for precise control over channel dimensions and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional patterning and etching processes are used, then manufacturing simplicity is maintained, but manufacturing precision deteriorates
Solution Approach 1:
The fabrication process is divided into multiple sequential patterning steps (e.g., self-aligned double patterning, self-aligned triple patterning) where each step creates a portion of the final pattern. This segmentation allows achieving sub-10nm precision that cannot be obtained through single-step conventional lithography, directly resolving the contradiction between manufacturing precision and process complexity.
Solution Approach 2:
Mandrel structures and spacer layers are formed in advance before the final active pattern is created. These preliminary structures serve as templates that guide subsequent etching steps, enabling precise nanoscale feature definition while maintaining process control. The preliminary action principle is evident in forming sacrificial mandrels that define the eventual gate and channel dimensions.
2Reliability
If gate-all-around structures are implemented, then device performance is improved, but ease of manufacture deteriorates
Solution Approach 1:
The gate structure completely surrounds the channel region in three dimensions, with gate material wrapped around the channel from top, bottom, and sidewalls. This nested configuration provides all-around control of the channel potential, achieving superior device performance through fuller depletion while the patent provides specific fabrication methods to make this complex structure manufacturable.
Solution Approach 2:
The gate structure transitions from planar two-dimensional control to three-dimensional all-around control, wrapping around the channel in the vertical dimension and lateral dimensions. This dimensional transition enables complete electrostatic control of the channel, improving device performance while requiring advanced fabrication techniques described in the patent.
3Productivity
If multi-gate devices with precise nanoscale control are fabricated, then device density is improved, but productivity deteriorates
Solution Approach 1:
The fabrication process uses universal mandrel and spacer formation techniques that can define multiple adjacent nanoscale features simultaneously through self-aligned processes. This multi-functionality allows creating arrays of high-density multi-gate devices using the same patterning sequence, improving productivity while maintaining precise nanoscale control across all features.
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 enables the creation of GAA FETs with improved performance by achieving fuller depletion in the channel region, reducing short-channel effects, and providing a direct frontside-to-backside connection for signal routing with lower resistance and capacitance, thus enhancing device density and efficiency.
Implementation Method 1
forming a gate structure over a semiconductor substrate; forming a source/drain epitaxial structure adjacent a side of the gate structure
Data Source
AI summary
A method for fabricating an integrated circuit structure is provided. The method includes forming a gate structure over a semiconductor substrate; forming a source/drain epitaxial structure adjacent a side of the gate structure; forming a first isolation structure in the gate structure, wherein the first isolation structure spaces apart a first portion of the gate structure from a second portion of the gate structure; forming a front-side metallization layer over a frontside of the semiconductor substrate, wherein the front-side metallization layer comprises a front-side metal feature overlapping the first isolation structure; depositing a dielectric layer over a backside of the semiconductor substrate; forming a conductive via in the dielectric layer and the first isolation structure, wherein the conductive via is in contact with a backside of the front-side metal feature.