Molybdenum Etch Depth Control via Thermal Oxidation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wet etching methods for molybdenum result in surface roughening and inadequate control over etch depth, which are undesirable for advanced interconnects and memory architectures in integrated circuit fabrication.
Innovation Solution
A method involving thermal oxidation to form a self-limiting molybdenum oxide layer, followed by its dissolution using a wet chemistry, allowing for controlled recessing of molybdenum features with reduced surface roughness and precise etch depth control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wet etching solutions (ozonated water or hydrogen peroxide) are used to etch molybdenum, then etching can be performed, but surface roughening occurs and etch depth control is inadequate
Solution Approach 1:
The etching process is segmented into discrete cycles, each consisting of oxidation followed by oxide removal. This allows precise control over etch depth by adjusting the number of cycles and oxidation time, while maintaining surface smoothness through controlled oxide formation and removal.
Solution Approach 2:
The patent employs periodic alternating action between oxidation and oxide removal steps. This periodic cycle enables controlled recessing of molybdenum surfaces with preserved smoothness, achieving both etch depth control and surface quality.
2Manufacturing precision
If thermal oxidation is used to form molybdenum oxide layer, then etch depth control is improved, but additional process steps are required
Solution Approach 1:
The thermal oxidation process is self-limiting, automatically stopping when the oxide layer reaches a thickness determined by temperature and time parameters. This self-regulating behavior simplifies process control and reduces the need for complex monitoring systems.
Solution Approach 2:
Etch depth is controlled by adjusting oxidation parameters (temperature, time, oxygen partial pressure) rather than requiring complex etching chemistry. This parameter-based control simplifies the overall process while maintaining high precision.
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 enables smooth etching of molybdenum surfaces with improved control over etch depth, reducing surface roughness and maintaining the smoothness of the molybdenum surface, suitable for advanced interconnects and memory architectures.
Implementation Method 1
oxidizing a thickness portion of the molybdenum feature using a thermal oxidation process to form a thermal molybdenum oxide layer
Implementation Method 2
dissolving the thermal molybdenum oxide layer using a wet chemistry
Data Source
AI summary
The disclosure relates to a method for etching a molybdenum feature, comprising the steps of: a) oxidizing a thickness portion of the molybdenum feature using a thermal oxidation process to form a thermal molybdenum oxide layer, and b) dissolving the thermal molybdenum oxide layer using a wet chemistry.