Level Contact Structure for Low-Capacitance Semiconductor Gates
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Solution Overview
Problem
The challenge in the semiconductor industry is to form reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes continue to decrease, affecting production efficiency and costs.
Innovation Solution
The formation of semiconductor device structures using FinFETs and nanostructure transistors with advanced patterning techniques such as double-patterning or multi-patterning processes, including the use of sacrificial layers, spacers, and epitaxial structures, along with gate stacks and source/drain structures, to achieve smaller pitches and improve device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency improves and costs lower, but fabrication process difficulty increases and reliability decreases
Solution Approach 1:
The fabrication process is divided into multiple patterning steps (e.g., self-aligned double patterning, self-aligned quadruple patterning) where each step creates a portion of the final pattern. This segmentation allows achievement of smaller feature sizes while maintaining control and reliability through staged processing rather than attempting to create all features in a single step.
Solution Approach 2:
Sacrificial layers are formed in advance before the final pattern is created. These preliminary structures guide subsequent self-aligned etching processes, ensuring precise feature formation at small dimensions while maintaining process control and device reliability.
2Quantity of substance
If feature sizes decrease to increase functional density, then more devices fit per chip area, but fabrication process complexity increases
Solution Approach 1:
Multiple patterning steps are merged through self-alignment mechanisms where each subsequent pattern is automatically aligned to previous features without requiring additional alignment operations. This merging of alignment functions into the self-aligned process reduces overall process complexity despite multiple patterning steps.
Solution Approach 2:
The self-aligned etching process uses the previously formed structures themselves as the alignment reference for subsequent patterning steps. The process serves its own alignment function without requiring external alignment systems, simplifying the overall fabrication complexity while achieving high device density.
3Manufacturing precision
If advanced patterning techniques are used to achieve smaller pitches, then device performance improves, but process difficulty increases
Solution Approach 1:
Sacrificial layers serve as intermediary structures that facilitate the creation of small-pitch features. These temporary structures enable precise pattern transfer through self-aligned etching, achieving high manufacturing precision while the intermediary nature of the sacrificial layers simplifies the overall process by providing a controlled mechanism for feature formation.
Data Source
AI summary
A method for forming a semiconductor device structure is provided. The method includes forming a gate stack and a source/drain structure over a substrate. The method includes removing the gate dielectric layer over the first sidewall of the gate electrode. The method includes forming a dielectric layer over the source/drain structure and the substrate. The gate stack is embedded in the dielectric layer. The method includes forming a contact structure in the dielectric layer and over the source/drain structure, wherein a first top surface of the contact structure is substantially level with a second top surface of the gate electrode.