FinFET End-to-End Critical Dimension Control via Polymer Coating
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Solution Overview
Problem
Existing FinFET devices face challenges in controlling the end-to-end critical dimension, which becomes increasingly difficult as device sizes decrease, leading to issues in forming high-k/MG stack structures and maintaining a vertical profile.
Innovation Solution
A coating layer, specifically a fluorine-containing polymer, is used to reduce the width of trenches and control the end-to-end critical dimension by adjusting its thickness, allowing for precise formation of smaller dimensions and a larger end cap distance, facilitating the creation of a high-k/MG stack structure with a more vertical profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography and etching methods are used to form FinFET devices, then the fabrication process is relatively simple, but the end-to-end critical dimension control becomes increasingly difficult as device sizes decrease
Solution Approach 1:
A coating layer is deposited on the mandrel structure before etching to pre-establish the desired critical dimension. This preliminary coating action allows the final etched feature to achieve the target dimension with higher precision, as the coating layer compensates for etching variations and provides a controlled starting point for dimension definition.
Solution Approach 2:
A coating layer is introduced as an intermediary material between the mandrel and the etching process. This intermediate layer acts as a dimensional buffer that can be precisely controlled in thickness, allowing better control over the final critical dimension while isolating the etching process from direct dependence on mandrel dimension precision.
2Productivity
If device sizes are reduced to increase device density, then higher device density is achieved, but controlling the end-to-end critical dimension becomes increasingly difficult
Solution Approach 1:
The critical dimension is controlled by changing the parameter of coating layer thickness rather than relying solely on mandrel dimension. By adjusting the coating thickness parameter, the final critical dimension can be precisely tuned even as device sizes are reduced, enabling continued scaling while maintaining dimensional control.
Solution Approach 2:
The coating layer is applied in advance to establish the dimensional reference before the etching process. This preliminary dimensional setting allows the etching process to proceed with more tolerance, enabling smaller device features to be formed with controlled critical dimensions despite the challenges of scaling.
3Manufacturing precision
If a coating layer is used to control the end-to-end critical dimension, then manufacturing precision is improved, but the fabrication process complexity increases
Solution Approach 1:
The coating layer serves multiple functions: it defines the critical dimension, acts as an etch stop layer, and provides a controlled interface for subsequent processing steps. By combining multiple functions into a single layer, the process complexity increase is minimized while achieving precise dimensional control.
Solution Approach 2:
The thickness of the coating layer is precisely controlled through deposition parameters, allowing the critical dimension to be adjusted by changing a single process parameter (coating thickness) rather than requiring complex mask and etch parameter adjustments. This simplifies the overall process control despite adding a deposition step.
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 method effectively controls the end-to-end critical dimension, enabling the formation of FinFET devices with improved dimensions and profiles, enhancing the fabrication of high-k/MG stack structures and preventing line-end bridge problems.
Implementation Method 1
A coating layer, specifically a fluorine-containing polymer, is used to reduce the width of trenches and control the end-to-end critical dimension by adjusting its thickness
Data Source
AI summary
A method for forming a fin field effect transistor (FinFET) device structure is provided. The FinFET device structure includes a substrate and a first fin structure and a second fin structure extending above the substrate. The FinFET device structure also includes a first transistor formed on the first fin structure and a second transistor formed on the second fin structure. The FinFET device structure further includes an inter-layer dielectric (ILD) structure formed in an end-to-end gap between the first transistor and the second transistor, and the end-to-end gap has a width in a range from about 20 nm to about 40 nm.