Atomic Layer Deposition Surface Pretreatment for Semiconductor Substrates
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Solution Overview
Problem
Conventional atomic layer deposition techniques face challenges with contamination issues, leading to device failure and reliability problems, especially when dealing with smaller feature sizes and complex circuit designs, where good step coverage is essential but often lacking in chemical vapor deposition methods.
Innovation Solution
A method involving a precursor treatment process that includes treating a semiconductor substrate with an oxidizing species to remove carbon-bearing species and native oxide layers, followed by a reducing species to create a clean surface, allowing for effective atomic layer deposition in a vacuum environment, thereby ensuring clean surfaces for improved film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical vapor deposition (CVD) techniques are used to form films, then film formation is achieved, but step coverage for smaller features (less than 0.2 μm) is poor
Solution Approach 1:
The patent transitions from CVD to atomic layer deposition (ALD) technique, changing the deposition parameter from continuous film growth to sequential monolayer formation. This parameter change enables excellent step coverage on high aspect ratio structures (aspect ratio about 10) while supporting continued device scaling to smaller geometries
Solution Approach 2:
The patent replaces the chemical vapor deposition mechanism with atomic layer deposition mechanism. ALD uses sequential surface reactions with precursors that self-limit the deposition process, providing conformal coverage on complex three-dimensional structures that CVD cannot achieve
2Manufacturing precision
If atomic layer deposition (ALD) techniques are used to achieve good step coverage, then film deposition quality improves, but contamination problems arise leading to device failure
Solution Approach 1:
The patent introduces a preliminary surface treatment process using ozone or oxygen plasma before ALD deposition. This pretreatment removes organic contaminants and carbon-bearing species from the substrate surface, creating a clean surface that prevents contamination-related device failures while maintaining the excellent step coverage benefits of ALD
Solution Approach 2:
The patent uses ozone or oxygen plasma as strong oxidizing environments to remove carbon-containing contaminants from the substrate surface. The oxidizing species react with and remove organic residues, leaving a clean surface for subsequent ALD processes and improving device reliability
3Productivity
If device geometry is reduced to increase circuit density, then more devices per wafer are achieved, but process limitations prevent further scaling
Solution Approach 1:
The patent employs atomic layer deposition with its unique parameter characteristics - sequential precursor introduction, self-limiting surface reactions, and low deposition temperatures. These parameter changes enable precise control of film thickness and composition on sub-0.2 μm features, allowing continued device scaling without compromising film quality or process control
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 enhances device yields by providing better step coverage and compatibility with conventional processes, enabling the integration of design rules for smaller feature sizes without substantial equipment modifications, resulting in higher quality films with reduced contamination.
Implementation Method 1
introducing an oxidizing species (e.g., ozone, oxygen bearing plasma) into the chamber. The method includes treating the upper surface of the semiconductor substrate with the oxidizing species to remove the one or more carbon bearing species
Implementation Method 2
A reducing species is introduced into the chamber to strip the particle film of silicon dioxide to create a substantially clean surface treated with hydrogen bearing species
Implementation Method 3
A reducing species is introduced into the chamber to strip the particle film of silicon dioxide to create a substantially clean surface treated with hydrogen bearing species
Data Source
AI summary
A method for forming atomic layer deposition. The method includes placing a semiconductor substrate (e.g., wafer, LCD panel) including an upper surface in a chamber. The upper surface includes one or more carbon bearing species and a native oxide layer. The method includes introducing an oxidizing species into the chamber. The method includes treating the upper surface of the semiconductor substrate to remove the one or more carbon bearing species and form a particle film of silicon dioxide overlying the upper surface. The method includes introducing an inert gas into the chamber to purge the chamber of the oxidizing species and other species associated with the one or more carbon bearing species. A reducing species is introduced into the chamber to strip the particle film of silicon dioxide to create a substantially clean surface treated with hydrogen bearing species. The method includes performing another process (e.g., atomic layer deposition) on the substantially clean surface while the substrate is maintained in a vacuum environment. The substantially clean surface is substantially free from native oxide and carbon bearing particles.