Replacement Gate Trench Gap Filling Without Seam Punch-Through
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Solution Overview
Problem
In advanced semiconductor processing, high-aspect ratio trenches in FinFET devices often result in seams or gaps in the gap-filling material, leading to a seam-induced punch-through effect during the metal gate etch-back process, which can cause over-etching and degrade device performance.
Innovation Solution
A fluorine treatment process is applied to the gap-filling material to remove seams by expanding the volume of the material, ensuring complete filling of the trenches and preventing the punch-through effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional gap-filling material deposition is used in high-aspect ratio trenches, then the trenches can be filled, but seams or gaps form in the filling material leading to punch-through effects
Solution Approach 1:
The patent applies fluorine treatment to the gap-filling material, changing its physical and chemical parameters. This treatment modifies the material's volume and surface properties, enabling it to expand and fill seams and gaps that formed during conventional deposition, thereby achieving uniform filling without punch-through effects
Solution Approach 2:
Fluorine acts as an intermediary substance that mediates the transformation of the gap-filling material. The fluorine treatment process introduces fluorine atoms into the material, which serves as a intermediate step to achieve the desired volume expansion and seam elimination, ultimately preventing punch-through without directly modifying the deposition process
2Productivity
If high-aspect ratio trenches are formed to increase integration density, then more components can be integrated, but seam-induced punch-through effects occur during metal gate etch-back
Solution Approach 1:
The fluorine treatment is applied preliminarily to the gap-filling material before the metal gate etch-back process. This preliminary action prevents the formation of seams and gaps during the filling process, ensuring that when the metal gate etch-back occurs later, there are no punch-through effects, thus maintaining filling uniformity while enabling high integration density
3Manufacturing precision
If fluorine treatment is applied to expand gap-filling material volume, then seams are eliminated, but additional process steps are required
Solution Approach 1:
The patent replaces mechanical deposition processes with a chemical treatment approach. Instead of relying solely on physical deposition methods to achieve uniform filling, the invention uses fluorine-based chemical treatment to modify the material properties and eliminate seams, substituting a chemical mechanism for a purely mechanical one, which consolidates the filling and seam-elimination functions into an integrated process
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 fluorine treatment effectively eliminates seams in the gap-filling material, preventing over-etching and improving device performance and production yields by ensuring uniform filling of the trenches, thus enhancing the reliability of the semiconductor device.
Implementation Method 1
A fluorine treatment process is applied to the gap-filling material to remove seams by expanding the volume of the material
Data Source
AI summary
A method of forming a semiconductor device includes: forming a dummy gate over a fin, where the fin protrudes above a substrate; surrounding the dummy gate with a dielectric material; and replacing the dummy gate with a replacement gate structure, where replacing the dummy gate includes: forming a gate trench in the dielectric material, where forming the gate trench includes removing the dummy gate; forming a metal-gate stack in the gate trench, where forming the metal-gate stack includes forming a gate dielectric layer, a first work function layer, and a gap-filling material sequentially in the gate trench; and enlarging a volume of the gap-filling material in the gate trench.