Conductive Dummy Gate Layer for Replacement Metal Gate Process
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Solution Overview
Problem
Aggressive etching techniques in semiconductor device manufacturing lead to imprecise devices, damaged surfaces, and residual layer issues, particularly in forming gate dielectric devices, which can interfere with device performance.
Innovation Solution
A method involving the formation of a conductive dummy gate layer, such as silicon germanium or titanium nitride, directly connected to the substrate, using a replacement metal gate process that avoids aggressive etching by removing the thick oxide layer at the high-performance transistor area early in the process, allowing for precise gate conductor formation without residual layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aggressive etching techniques are used to remove dummy gate layers, then gate dielectric devices can be formed, but manufacturing precision deteriorates resulting in imprecise devices and damaged surfaces
Solution Approach 1:
The thick gate oxide layer is removed in advance, before the dummy gate layer is formed. This preliminary removal of the thick oxide eliminates the need for aggressive etching later in the process, as the dummy gate layer can be directly patterned and etched without the interfering thick oxide residue that would require harsh etching conditions
Solution Approach 2:
The conventional sequence is inverted: instead of forming the dummy gate layer first and then using aggressive etching to remove it along with thick oxide, the patent removes the thick oxide first and then forms the dummy gate layer. This reversal eliminates the need for aggressive etching while achieving the same gate dielectric device formation
2Ease of manufacture
If aggressive etching is used to remove thick gate dielectric, then gate regions can be defined, but device reliability deteriorates due to damaged surfaces and unintentional layer residue
Solution Approach 1:
The thick gate dielectric is removed preliminarily before dummy gate formation, eliminating the need for subsequent aggressive etching that would damage surfaces and leave residue. This early removal ensures clean surfaces and complete etching without compromising device reliability
Solution Approach 2:
The patent converts the potential harm of thick oxide interference into a benefit by removing it early, which then allows for gentle, precise etching of the dummy gate layer without the need for aggressive conditions that would cause surface damage and residue
3Object-affected harmful factors
If etching is stopped early to avoid damage, then device damage is reduced, but manufacturing precision deteriorates due to residual oxide layers
Solution Approach 1:
The thick oxide removal is performed preliminarily with gentle etching, separating this step from the dummy gate etching. This allows the dummy gate etching to be performed with high precision using mild conditions, while the thick oxide is already gone and won't interfere or require aggressive etching
Data Source
AI summary
A method of manufacturing a semiconductor device including a replacement metal gate process incorporating a conductive dummy gate layer (e.g., silicon germanium (SiGe), titanium nitride, etc.) and a related are disclosed. The method includes forming an oxide layer on a substrate; removing a gate portion of the oxide layer from the substrate in a first region of the semiconductor device; forming a conductive dummy gate layer on the semiconductor device in the first region; and forming a gate on the semiconductor device, the gate including a gate conductor disposed in the first region and directly connected to the substrate.