NSFET STI Protection Structure for Selective Etch Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices continue to integrate more components into a given area with reduced feature sizes, challenges arise in protecting shallow trench isolation (STI) regions during the etching process for forming nanostructure field-effect transistors (NSFETs), leading to potential damage and loss of these regions.
Innovation Solution
A shallow trench isolation protection structure is formed with a liner layer and a hard mask layer, manipulated through various processing steps to achieve different profiles, and enhanced using plasma processes to improve resistance to etching, thereby protecting the STI regions during the disposal of a disposable oxide interposer process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching processes are used for forming NSFETs, then manufacturing simplicity is maintained, but STI regions suffer damage and loss during etching
Solution Approach 1:
The STI protection structure is formed in advance before the etching process that removes the disposable oxide interposer. This preliminary formation ensures that the STI regions are protected during subsequent etching operations, preventing damage and loss while maintaining manufacturing simplicity
Solution Approach 2:
The STI protection structure acts as an intermediary layer between the etching process and the STI regions. It provides a protective barrier that mediates the interaction between the harsh etching environment and the vulnerable STI regions, preventing direct damage
2Productivity
If feature sizes are reduced to increase integration density, then more components can be integrated, but STI regions become more vulnerable to damage during etching
Solution Approach 1:
The STI protection structure provides localized protection specifically at the STI regions where it is most needed. The structure can be formed with varying thicknesses and material compositions tailored to the specific vulnerability of each STI region, allowing precise protection without affecting other device areas
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
The solution allows for precise control of the STI protection structure's profile, preventing damage during etching and ensuring the integrity of the STI regions, which is crucial for maintaining the functionality and reliability of NSFET devices.
Implementation Method 1
enhanced using plasma processes to improve resistance to etching
Data Source
AI summary
Various examples related to a shallow trench isolation (STI) protection structure formed on the STI regions of a nanostructure field-effect transistor (NSFET) device are disclosed. The STI protection structure protects the STI regions (e.g., portions directly under dummy gate structures) during a subsequent selective etching process. The STI protection structures includes a liner layer and a hard mask layer(s) formed on the liner layer. In a first set of examples, the hard mask layer(s) on the liner layer are manipulated by various processing steps to achieve different profiles (e.g., concave, convex, or flat) for the upper surfaces of the STI protection structure. A second set of examples are disclosed for enhancing the quality of the liner layer of the STI protection structure through different plasma processes, such that the liner layer is more resistant to the subsequent etching process.