Semiconductor Dielectric Layer Annealing for Leakage Reduction
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Solution Overview
Problem
Conventional semiconductor devices face issues with poly-silicon gates due to boron penetration and depletion, leading to inferior performance and increased gate dielectric layer thickness, which necessitates the use of work function metals and requires effective dielectric layer formation to improve electrical performance and processing efficiency.
Innovation Solution
A semiconductor process involving two in-situ annealing processes with different imported gases and temperatures is performed on a dielectric layer, reducing circuit leakage density and improving material properties, while minimizing substrate damage and pollution by concentrating nitrogen atoms near the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate annealing processes are performed in different processing chambers, then the dielectric layer can be treated with different gases and temperatures, but the processing time increases and the dielectric layer may be polluted during chamber transfers
Solution Approach 1:
The patent combines two separate annealing processes into a single integrated process performed in one processing chamber. The chamber can switch between different gas environments (oxygen-containing and nitrogen-containing) and temperature conditions sequentially, eliminating the need for chamber transfers and reducing processing time while maintaining dielectric layer quality through controlled in-situ treatment.
Solution Approach 2:
The annealing process employs periodic alternation between different gas environments and temperature conditions within the same chamber. The system cycles through oxygen-containing atmosphere at elevated temperatures followed by nitrogen-containing atmosphere at different temperatures, achieving multiple treatment objectives through time-periodic parameter variation without physical chamber changes.
2Reliability
If nitrogen atoms are introduced into the dielectric layer, then the electrical performance is improved, but nitrogen concentration near the substrate may cause pollution and damage
Solution Approach 1:
The patent applies local quality control by introducing nitrogen atoms preferentially into specific regions of the dielectric layer while maintaining low nitrogen concentration near the substrate interface. The annealing process creates a nitrogen concentration gradient where the upper portions of the dielectric layer benefit from nitrogen incorporation for improved electrical properties, while the substrate region remains protected from nitrogen-induced pollution and damage.
Solution Approach 2:
The process performs preliminary nitrogen introduction into the dielectric layer through controlled annealing before potential subsequent processing steps. By establishing the desired nitrogen distribution profile early in the process through in-situ annealing, the dielectric layer is prepared with optimal electrical properties while preventing nitrogen migration to the substrate in later processing stages.
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 process enhances the reliability and electrical performance of semiconductor structures by reducing circuit leakage and substrate damage, and shortens processing time by eliminating the need for multiple pre-heating steps and chamber transfers.
Implementation Method 1
Two annealing processes are performed in-situly on the dielectric layer, wherein the two annealing processes have different imported gases and different annealing temperatures
Implementation Method 2
two annealing processes have different imported gases and different annealing temperatures
Implementation Method 3
pollution and damages of the substrate caused by plasma or dopants can be reduced
Data Source
AI summary
A semiconductor structure includes a dielectric layer located on a substrate, wherein the dielectric layer includes nitrogen atoms, and the concentration of the nitrogen atoms in the dielectric layer is lower than 5% at a location wherein the distance between this location in the dielectric layer to the substrate is less than 20% of the thickness of the dielectric layer. Moreover, the present invention provides a semiconductor process including the following steps: a dielectric layer is formed on a substrate. Two annealing processes are performed in-situly on the dielectric layer, wherein the two annealing processes have different imported gases and different annealing temperatures.