SOI Oxide Stripping With Ozone to Prevent Surface Projections
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Solution Overview
Problem
Existing methods fail to effectively remove oxide from silicon-on-insulator structures without forming raised projections on the surface.
Innovation Solution
A method involving immersion in a hydrofluoric acid and surfactant bath followed by ozone treatment and subsequent cleaning with SC-1 and optionally SC-2 baths to remove oxide and defects from silicon-on-insulator structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the stripping process time is increased to remove oxide completely, then oxide removal is improved, but raised projections form on the surface
Solution Approach 1:
The patent introduces ozone as an intermediary substance between the stripping process and the silicon surface. The ozone treatment modifies the surface chemistry to prevent projection formation during oxide removal, acting as a mediator that enables complete stripping without the harmful side effect of surface deformation
Solution Approach 2:
The patent changes the chemical parameters of the stripping environment by introducing ozone and controlling the composition of the stripping solution. This parameter modification allows the stripping process to proceed completely while preventing the formation of raised projections through altered surface reaction conditions
2Ease of manufacture
If conventional cleaning methods are used after oxide stripping, then cleaning is achieved, but nano-scale defects remain that cause surface projections
Solution Approach 1:
The patent applies ozone treatment as a preliminary action before the main cleaning process. This pre-treatment step modifies the surface to prevent defect formation that would otherwise lead to projections, addressing the problem before it manifests during conventional cleaning
Solution Approach 2:
The patent uses ozone, a strong oxidant, to accelerate the oxidation and removal of surface contaminants and defects. This strong oxidative action effectively eliminates nano-scale defects that conventional cleaning methods cannot remove, preventing projection formation
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 method effectively removes oxide and reduces or eliminates nano-scale defects, preventing the formation of surface projections.
Implementation Method 1
The silicon-on-insulator structure is immersed in a stripping bath to strip the oxide film from the surface of the silicon-on-insulator structure. The stripping bath includes hydrofluoric acid and a surfactant.
Implementation Method 2
The stripped silicon-on-insulator structure is immersed in an ozone bath comprising ozone to prepare an ozone-treated silicon-on-insulator structure.
Implementation Method 3
The ozone-treated silicon-on-insulator structure is immersed in an SC-1 bath comprising ammonium hydroxide and hydrogen peroxide to prepare a SC-1 treated silicon-on-insulator structure.
Data Source
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AI summary
Methods for removing an oxide film and for cleaning silicon-on-insulator structures are disclosed. The methods may involve immersing the silicon-on-insulator structure in a stripping bath to strip an oxide film from the surface of the silicon-on-insulator structure. The stripped silicon-on-insulator structure is immersed in an ozone bath comprising ozone. The ozone-treated silicon-on-insulator structure may be immersed in an SC-1 bath comprising ammonium hydroxide and hydrogen peroxide to clean the structure.