Semiconductor Isolation Structure for FinFET Patterning Precision
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, affecting production efficiency and cost.
Innovation Solution
The process involves forming fin structures and gate all-around transistor structures using double-patterning or multi-patterning techniques, with sacrificial layers and epitaxial growth, to create semiconductor device structures that enable efficient patterning and etching, allowing for the formation of reliable devices at smaller scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs lower, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple discrete stages including forming isolation structures before fin structures, selective epitaxial growth in different regions, and multi-step patterning. Each stage is independently optimized to reduce overall process complexity while enabling smaller feature sizes and higher functional density.
Solution Approach 2:
Isolation structures are formed in advance before fin structures and transistor components. Sacrificial layers are deposited and patterned beforehand to guide subsequent self-aligned processes. This preliminary structuring simplifies later fabrication steps by pre-establishing geometric constraints and material regions.
2Productivity
If feature sizes decrease to increase functional density, then more devices fit per chip area, but manufacturing reliability becomes more difficult to achieve
Solution Approach 1:
Different regions of the semiconductor device are assigned different material compositions and structural properties. Isolation structures use specific dielectric materials with tailored mechanical and electrical properties. Fin structures and channel regions have differentiated doping profiles and crystal orientations. This local optimization ensures each region performs reliably at reduced dimensions.
Solution Approach 2:
Material parameters such as epitaxial growth rates, doping concentrations, and layer thicknesses are precisely controlled and adjusted for different device regions. These parameter changes enable maintenance of electrical performance and manufacturing yield despite reduced feature sizes, ensuring reliability while increasing functional density.
3Manufacturing precision
If double-patterning or multi-patterning techniques are used to form fin structures and gate all-around transistor structures, then patterning precision improves, but process complexity increases
Solution Approach 1:
Multiple patterning layers are nested within each other through self-aligned processes. First patterning defines isolation structures, then fin structures are formed aligned to those isolations, followed by gate structures aligned to fins. Each patterning step nests within the geometric framework established by previous steps, achieving high precision while managing complexity through self-alignment.
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 ability to form reliable semiconductor devices by improving patterning precision and etching selectivity, reducing complexity, and maintaining production efficiency while lowering costs.
Implementation Method 1
an epitaxial structure formed over the fin structure and underlying substrate
Data Source
AI summary
A semiconductor device structure and a method for forming a semiconductor device structure are provided. The semiconductor device structure includes a semiconductor fin over a substrate and multiple semiconductor nanostructures suspended over the semiconductor fin. The semiconductor device structure also includes a gate stack extending across the semiconductor fin, and the gate stack wraps around each of the semiconductor nanostructures. The semiconductor device structure further includes a first epitaxial structure and a second epitaxial structure sandwiching the semiconductor nanostructures. Each of the first epitaxial structure and the second epitaxial structure extends exceeding a top surface of the semiconductor fin. In addition, the semiconductor device structure includes an isolation structure between the semiconductor fin and the gate stack. The isolation structure further extends exceeding opposite sidewalls of the first epitaxial structure.