Semiconductor Surface Preparation via Oxide Transformation
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Solution Overview
Problem
Existing methods for preparing semiconductor substrates, such as Direct Silicon Bonding (DSB) and strained silicon layer formation, are hindered by the presence of oxygen or oxide precipitates, leading to low bonding energies and defects due to insufficient removal of native oxide layers.
Innovation Solution
A method that transforms natural oxide into an artificial oxide, followed by its removal using treatments like HF, reducing plasma, or thermal processes, to achieve superior hydrophobic surfaces and prevent native oxide regrowth, enhancing bonding energy and crystalline quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If HF treatment is applied directly on natural oxide, then oxide removal is achieved, but bonding energy remains low and defects persist
Solution Approach 1:
The method applies preliminary oxidation treatment before the reducing treatment. By first transforming the natural oxide into an artificial oxide layer, the subsequent HF treatment becomes more effective at removing all oxide traces, resulting in superior hydrophobic surfaces and higher bonding energy compared to direct HF treatment on natural oxide.
2Object-generated harmful factors
If natural oxide is removed directly, then surface is cleaned, but native oxide regrowth occurs and bonding quality deteriorates
Solution Approach 1:
The preliminary oxidation step transforms the unstable natural oxide into a stable artificial oxide layer that can be completely removed by the subsequent reducing treatment. This two-step process ensures more complete oxide removal and creates superior hydrophobic surfaces that prevent native oxide regrowth, thereby improving bonding energy.
3Manufacturing precision
If reducing plasma treatment is used, then oxide removal is improved, but surface roughness quality needs enhancement
Solution Approach 1:
The method uses a composite plasma treatment comprising both reducing gas plasma (for oxide removal) and inert gas plasma (for surface roughness optimization). The reducing plasma component removes the artificial oxide layer effectively, while the inert gas plasma component enhances the surface roughness quality, achieving both oxide removal and surface quality improvement simultaneously.
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 results in significantly improved bonding energies and crystalline quality of semiconductor substrates, with bonding energies increased by a factor of at least 10 and reduced defects, such as 'watermarks', compared to traditional methods.
Implementation Method 1
the semiconductor substrate is placed into an oxidizing environment (8) which transforms the native oxide layer (5) into an artificial oxide layer (7)
Implementation Method 2
The reducing step leads to the chemical removal of the artificial oxide layer (7) so that, in the end, an oxide-free substrate surface is achieved
Implementation Method 3
superior hydrophobic surfaces were achieved so that the native oxide layer growth can be better suppressed
Data Source
AI summary
The invention relates to a method for preparing a surface of a semiconductor substrate by oxidizing the surface of the semiconductor substrate to thereby transform the natural oxide into an artificial oxide and then removing the artificial oxide, in particular to obtain an oxide-free substrate surface.