FinFET Gate Taper Profile Using Oblique-Angle Ion Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor fabrication processes face challenges in achieving precise control over deposition and etching processes, particularly in forming desired device profiles, leading to incomplete patterning and uneven processing of semiconductor devices.
Innovation Solution
A directional deposition and etching process using oblique-angle ion beams and a movable wafer stage to selectively deposit materials and etch regions, ensuring uniform ion distribution and targeted processing of semiconductor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition and etching processes are used, then basic device operation and physical dimensions are achieved, but manufacturing precision and uniformity of device profiles deteriorate
Solution Approach 1:
The fabrication process is divided into multiple sequential deposition and etching steps, each forming a specific layer or structure (e.g., first dielectric layer, first conductive layer, second dielectric layer). This segmentation allows precise control over each individual layer's properties while maintaining overall process manageability, directly addressing the need for manufacturing precision without overwhelming complexity.
Solution Approach 2:
Different materials and process parameters are used for different layers and regions of the device. For example, alternating between dielectric materials (silicon oxide, silicon nitride) and conductive materials (tungsten, copper), and adjusting deposition/etching parameters for each specific layer to achieve optimal local properties, thereby improving overall device profile precision.
2Reliability
If deposition and etching processes are controlled to enhance device characteristics, then device performance and yield improve, but process complexity and difficulty of control increase
Solution Approach 1:
Dielectric layers are deposited and patterned in advance to form mandrels, spacers, and isolation structures before conducting etching operations. For example, the first dielectric layer is formed with patterned regions that guide subsequent etching steps, ensuring precise feature formation and improving device yield by preventing errors in later stages.
Solution Approach 2:
Dielectric layers serve as intermediary structures that facilitate the formation of conductive features. The patterned dielectric layers act as masks and spacers that mediate the etching process, enabling precise control over conductive feature geometry and position, thereby improving device yield while managing process complexity.
3Manufacturing precision
If ion beams are used for directional deposition and etching, then manufacturing precision and uniformity improve, but equipment complexity and energy consumption increase
Solution Approach 1:
The ion beam is applied at oblique angles (e.g., 45 degrees) rather than perpendicular to the substrate. This partial action approach provides directional control for improved manufacturing precision and uniformity in specific regions, while avoiding the excessive energy consumption that would result from normal incidence ion beam processing across the entire wafer surface.
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 precise control over semiconductor device fabrication, improving the uniformity and accuracy of device profiles by ensuring even ion distribution and targeted processing, thereby enhancing device performance and yield.
Implementation Method 1
a directional deposition process is performed using oblique-angle ion beams to deposit a protective layer on selected regions of the wafer
Implementation Method 2
a directional etching process is performed using oblique-angle ion beams to etch exposed regions of the wafer
Data Source
AI summary
A semiconductor device includes a substrate having a semiconductor fin. A gate structure is over the semiconductor fin, in which the gate structure has a tapered profile and comprises a gate dielectric. A work function metal layer is over the gate dielectric, and a filling metal is over the work function metal layer. A gate spacer is along a sidewall of the gate structure, in which the work function metal layer is in contact with the gate dielectric and a top portion of the gate spacer. An epitaxy structure is over the semiconductor fin.