Plasma Substrate Cleaning via Oxygen Layer Cycling
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Solution Overview
Problem
Conventional methods for cleaning semiconductor substrates, such as wet cleaning and plasma cleaning, face challenges like wafer-to-wafer variation and contamination issues, which affect the quality of the epitaxial silicon layer formation.
Innovation Solution
A method involving a cleaning chamber that uses a plasma process with an oxygen-containing gas to form and remove oxidized layers on the substrate surface, employing a gettering material to trap contaminants and minimize damage, and adjusting RF power to create a low-energy plasma for effective cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wet cleaning processes are used, then cleaning effectiveness is improved, but wafer-to-wafer variation increases due to queue time issues
Solution Approach 1:
The patent replaces conventional wet cleaning processes with a plasma-based cleaning system. The plasma cleaning chamber uses ionized gas to clean substrate surfaces without the mechanical handling and queue time variations inherent in wet cleaning processes, thereby improving wafer-to-wafer consistency while maintaining cleaning effectiveness.
Solution Approach 2:
The patent employs controlled plasma parameters including RF power levels, gas composition (oxygen-containing gas), and pressure conditions to optimize cleaning effectiveness. By precisely controlling these parameters, the system achieves consistent cleaning results across multiple wafers, eliminating the variability associated with conventional wet cleaning queue times.
2Manufacturing precision
If conventional plasma cleaning processes are used, then cleaning action is improved, but contamination of chamber and substrates increases due to unwanted species formation
Solution Approach 1:
The patent applies local quality by creating a controlled plasma environment with specific gas compositions and energy levels tailored to the cleaning task. The plasma is generated in a confined chamber with controlled atmosphere, allowing effective cleaning action while preventing unwanted species from contaminating the chamber and substrates. The oxygen-containing gas is specifically selected to produce desirable cleaning species while minimizing harmful byproducts.
Solution Approach 2:
The patent uses an oxygen-containing gas atmosphere in the plasma cleaning chamber that creates a controlled environment for cleaning. This controlled atmospheric composition allows effective oxidation-based cleaning while preventing the formation of unwanted contaminating species that would occur in conventional plasma environments, thus reducing chamber and substrate contamination.
3Manufacturing precision
If high energy plasma is used for cleaning, then cleaning effectiveness is improved, but substrate damage increases
Solution Approach 1:
The patent optimizes plasma parameters including RF power levels, gas pressure, and composition to achieve effective cleaning at reduced energy levels. By carefully controlling these parameters, the system maintains sufficient cleaning effectiveness while minimizing substrate damage that would result from high energy plasma bombardment.
Solution Approach 2:
The patent employs a controlled plasma process that applies just sufficient energy to achieve effective cleaning without excessive energy input that would cause substrate damage. The oxygen-containing plasma is tuned to provide adequate cleaning action while maintaining energy levels below the threshold for significant substrate damage.
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 ensures a clean and damage-free substrate surface, reducing defects and stress in the epitaxial layer, thereby improving the consistency and quality of semiconductor processing.
Implementation Method 1
exposing a surface of the substrate disposed in the processing chamber to an oxygen containing gas to form a first oxygen containing layer on the surface
Implementation Method 2
A method involving a cleaning chamber that uses a plasma process with an oxygen-containing gas to form and remove oxidized layers on the substrate surface
Implementation Method 3
employing a gettering material to trap contaminants and minimize damage
Data Source
AI summary
Embodiments described herein provide methods for processing a substrate. One embodiment comprises positioning a substrate in a processing region of a processing chamber, exposing a surface of the substrate disposed in the processing chamber to an oxygen containing gas to form a first oxygen containing layer on the surface, removing at least a portion of the first oxygen containing layer to expose at least a portion of the surface of the substrate, and exposing the surface of the substrate to an oxygen containing gas to form a second oxygen containing layer on the surface.