Selective Oxidation of Silicon Using In-Situ Steam Generation
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Solution Overview
Problem
Conventional oxidation processes in semiconductor manufacturing often degrade gate oxide layers by oxidizing both desired and undesired layers, particularly metals and barrier layers, due to the lack of selective oxidation methods that efficiently oxidize silicon-containing materials without damaging other components.
Innovation Solution
A method involving a hydrogen-rich gas mixture with an oxygen containing gas, pressurized to between 250 and 800 torr, and heated to temperatures between 700°C and 1000°C, is used to selectively oxidize silicon-containing materials within a semiconductor device, utilizing in-situ steam generation to avoid oxidizing metal or barrier layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional oxygen rich oxidation processes are used, then oxidation of silicon containing materials occurs, but undesired oxidation of metal and barrier layers also occurs degrading device properties
Solution Approach 1:
The patent changes the chemical composition parameters of the oxidizing atmosphere by using a hydrogen-rich gas mixture (greater than 65% hydrogen) instead of conventional oxygen-rich mixtures. This parameter change enables selective oxidation of silicon-containing materials while preventing oxidation of metal and barrier layers, achieving up to 99.6% selectivity
Solution Approach 2:
The patent creates a controlled hydrogen-rich atmosphere that acts as a selective chemical environment. The hydrogen-rich mixture with controlled oxygen content creates conditions where silicon oxidizes preferentially while metals and barrier layers remain protected, effectively creating a selective chemical environment
2Productivity
If wet oxidation or steam oxidation processes are used to increase oxidation rate, then oxide growth speed improves, but selectivity against metal and barrier layers deteriorates
Solution Approach 1:
The patent simultaneously optimizes multiple parameters: using a hydrogen-rich gas mixture (greater than 65% hydrogen), controlling chamber pressure (250-800 torr), and setting temperature (700°C-1000°C). This combination achieves both high oxidation rates and high selectivity (up to 99.6%), resolving the trade-off between productivity and manufacturing precision
3Manufacturing precision
If high pressure and long soak times are used in hydrogen combustion chamber, then selective oxidation efficiency improves, but hydrogen gas attacks barrier and hard mask layers forming unwanted metal silicide layers
Solution Approach 1:
The patent optimizes the pressure parameter to a specific range (250-800 torr) and uses a hydrogen-rich mixture (greater than 65% hydrogen) with controlled oxygen content. This parameter optimization achieves high selective oxidation efficiency while preventing hydrogen attack on barrier and hard mask layers, avoiding formation of unwanted metal silicide layers
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 allows for the selective oxidation of silicon-containing layers with high selectivity, up to 99.6% relative to tungsten metal, while maintaining the integrity of metal and barrier layers, thereby improving the electrical characteristics of semiconductor devices.
Implementation Method 1
heating the chamber to a predetermined temperature for a predetermined time to cause the hydrogen containing gas and the oxygen contain gas to react inside the chamber
Implementation Method 2
selectively oxidizing the silicon containing materials of the composite substrate
Implementation Method 3
selectively oxidizing the silicon containing materials of the composite substrate... selectively oxidizing silicon containing materials without oxidizing metals or barrier layers
Data Source
Figure 1A~1C
Figure 2
Figure 3A
AI summary
A method for selective oxidation of silicon containing materials in a semiconductor device is disclosed and claimed. In one aspect, a rapid thermal processing apparatus (200) is used to selectively oxidize a substrate (214) by in-situ steam generation at high pressure in a hydrogen rich atmosphere. Other materials, such as metals and barrier layers, in the substrate (214) are not oxidized.