Low-K Dielectric Spacer for FinFET Gate Cut
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gate cut patterning and etching processes in FinFET fabrication cause fin damage and yield reduction, especially for critical gate cuts of small dimensions, due to limited process margin and incomplete dummy gate removal.
Innovation Solution
A method involving the formation of a dielectric spacer using a low-k dielectric material between semiconductor fins, which eliminates the need for critical gate cuts by allowing non-critical mask usage, reducing fin damage and improving yield through controlled spacer thickness and etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional gate cut patterning and etching processes are used, then the dummy gate can be divided into segments, but fin damage occurs and yield is reduced
Solution Approach 1:
A dielectric spacer is introduced as an intermediary structure between adjacent fins. This spacer serves as a protective barrier during the gate cut process, preventing etching damage to the fins while allowing the dummy gate to be segmented. The spacer is formed by depositing dielectric material conformally over the substrate and then performing anisotropic etching to create vertical sidewalls that protect the fin regions during subsequent processing steps.
Solution Approach 2:
The dielectric spacer is formed in advance before the gate cut process is performed. This preliminary formation of the protective spacer structure ensures that the fins are protected during the subsequent dummy gate segmentation process, eliminating the need for critical dimension control in the gate cut itself and preventing fin damage that would otherwise occur during etching.
2Manufacturing precision
If critical gate cuts of small dimensions are performed, then the dummy gate segmentation is achieved, but process margin is limited and incomplete pull occurs
Solution Approach 1:
The dielectric spacer acts as a non-critical intermediary structure that defines the segmentation locations without requiring precise small-dimension patterning. The spacer thickness can be controlled with standard deposition processes, and its presence as a physical barrier enables reliable dummy gate pull during subsequent processing, eliminating the yield losses associated with incomplete removal in critical gate cut processes.
3Reliability
If the dielectric spacer is formed with low-k dielectric material, then fin damage is reduced and process margin is enhanced, but additional manufacturing steps are required
Solution Approach 1:
The use of low-k dielectric material changes the physical parameters of the spacer structure, providing better protection to the fins during processing. The low-k material has different mechanical and chemical properties that reduce damage to adjacent fin structures. Although this adds a material selection parameter, the deposition and etching processes remain standard semiconductor manufacturing techniques.
Data Source
AI summary
Structures including one or more field-effect transistors and methods for forming a structure that includes one or more field-effect transistors. A first semiconductor fin and a second semiconductor fin are formed in which the second semiconductor fin is spaced from the first semiconductor fin. A semiconductor layer is formed that covers the first semiconductor fin and the second semiconductor fin. An opening is formed in the semiconductor layer that exposes the first semiconductor fin. A dielectric spacer is formed on at least one sidewall of the semiconductor layer bordering the opening.