FinFET Fin Capping for Dimension Control and Out-Diffusion Blocking
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Solution Overview
Problem
The semiconductor industry faces challenges in controlling the critical dimensions, shapes, and sizes of semiconductor fins during the manufacturing of FinFETs, particularly in preventing material out-diffusion and ensuring precise formation of gate structures, which affects the integration density and performance of electronic components.
Innovation Solution
The method involves forming a protective semiconductor layer over the semiconductor fins, selecting varying thicknesses for different materials, and using a capping layer to control oxidation and out-diffusion, while also forming isolation regions and gate structures to maintain precise dimensions and prevent material loss during subsequent processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing processes are used for FinFETs, then production can proceed with standard methods, but control over critical dimensions, shapes, and sizes of semiconductor fins deteriorates
Solution Approach 1:
A protective semiconductor layer is formed over the semiconductor fins before subsequent processing steps. This preliminary protective action prevents material out-diffusion during later high-temperature or chemically aggressive processes, thereby maintaining precise fin dimensions and shapes without requiring complete process redesign
Solution Approach 2:
The protective semiconductor layer is selectively formed with varying thicknesses over different regions of the semiconductor fins. This local variation in layer thickness provides enhanced dimensional control in critical areas while maintaining process feasibility, resolving the contradiction between precision and complexity
2Reliability
If no protective layer is formed over semiconductor fins, then the manufacturing process remains simple, but material out-diffusion occurs during subsequent processing steps
Solution Approach 1:
The protective semiconductor layer acts as an intermediary barrier between the semiconductor fin material and the subsequent processing environment. This intermediate layer prevents direct interaction that would cause out-diffusion, while being integrated into the existing manufacturing flow to minimize added complexity
Solution Approach 2:
The protective layer is formed in advance before subsequent processing steps that could cause material out-diffusion. This preliminary protective measure ensures material stability during later processing without requiring complex in-process interventions
3Manufacturing precision
If varying thicknesses of protective layers are formed over different fins, then control over critical dimensions improves, but the manufacturing process becomes more complex
Solution Approach 1:
The protective semiconductor layer is formed with spatially varying thicknesses tailored to specific fin regions requiring enhanced dimensional control. This local quality approach provides precise control where needed while using thinner or standard thickness elsewhere, balancing manufacturing precision with ease of manufacture
Solution Approach 2:
The thickness parameter of the protective semiconductor layer is varied across different fin structures based on their specific dimensional control requirements. This parameter change enables differentiated protection levels that optimize critical dimension control while managing manufacturing complexity through controlled variation rather than complete process overhaul
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 control over fin dimensions and shapes, reduces material out-diffusion, and improves the efficiency of subsequent processing steps, such as forming gate structures, thereby increasing integration density and performance of semiconductor devices.
Implementation Method 1
using a capping layer to control oxidation and out-diffusion
Implementation Method 2
to prevent or reduce out-diffusion of materials of the semiconductor fins during subsequent processing steps
Data Source
AI summary
In an embodiment, a method includes forming a first fin and a second fin within an insulation material over a substrate, the first fin and the second fin includes different materials, the insulation material being interposed between the first fin and the second fin, the first fin having a first width and the second fin having a second width; forming a first capping layer over the first fin; and forming a second capping layer over the second fin, the first capping layer having a first thickness, the second capping layer having a second thickness different from the first thickness.