Precleaning Apparatus for Semiconductor Substrates
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Solution Overview
Problem
The miniaturization of semiconductor devices and the use of low-dielectric materials have made precleaning processes more complex, leading to incomplete removal of residues such as oxides and impurities, which can cause defects in epitaxial growth, especially due to the presence of carbon and other undesired elements.
Innovation Solution
A precleaning apparatus and method that includes a hydrogen baking process under a hydrogen atmosphere at 800° C or lower, followed by plasma etching and the use of halogen-based gases to remove oxides and semiconductor surface layers, effectively diffusing and removing impurities like carbon, thereby preparing the substrate for epitaxial regrowth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional precleaning processes are used, then the process is simple, but residues such as oxides and impurities are not properly removed
Solution Approach 1:
The precleaning process is divided into multiple distinct steps: hydrogen baking to remove organic contaminants, plasma etching to remove oxides, and halogen-based gas treatment to remove remaining impurities. Each step targets specific types of residues, ensuring thorough cleaning while maintaining process control and manageability.
Solution Approach 2:
The process utilizes changes in temperature (heating to 800°C or lower for hydrogen baking), gas phase transitions (plasma generation), and chemical composition (introducing halogen-based gases) to effectively remove different types of residues. These parameter changes enable comprehensive cleaning that addresses both oxides and organic impurities.
2Manufacturing precision
If miniaturization is pursued, then device performance is improved, but residue removal becomes more difficult
Solution Approach 1:
The precleaning process is performed before epitaxial regrowth to prevent contamination of the new epitaxial layer. By removing residues in advance through hydrogen baking, plasma etching, and halogen gas treatment, the process ensures that no contaminants are introduced during the critical epitaxial growth phase, maintaining high growth quality despite device miniaturization.
Solution Approach 2:
The process employs a composite cleaning approach combining thermal treatment (hydrogen baking), plasma chemistry, and halogen-based chemical etching. This multi-method approach addresses the complex contamination issues arising from miniaturization and low-dielectric material usage, effectively removing both organic and inorganic residues.
3Manufacturing precision
If heating is applied to remove residues, then cleaning effectiveness is improved, but substrate damage may occur
Solution Approach 1:
The heating temperature is controlled to be 800°C or lower during hydrogen baking, which is sufficient to remove organic contaminants and facilitate hydrogen diffusion into the substrate without causing thermal damage. This parameter optimization balances cleaning effectiveness with substrate protection.
Solution Approach 2:
Hydrogen atmosphere is used during the heating process to provide a reducing environment that prevents oxidation of the substrate surface while removing organic contaminants. The inert hydrogen environment protects the substrate from thermal oxidation damage that would occur in air or oxygen-containing atmospheres at high temperatures.
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 thorough removal of residues and impurities, enhancing the quality of epitaxial growth by addressing the structural changes and contamination issues in miniaturized semiconductor devices, allowing for efficient epitaxial regrowth and improved device performance.
Implementation Method 1
a heating unit configured to heat the substrate on the substrate support
Implementation Method 2
heat-treating a substrate having a contaminated or damaged portion under a hydrogen atmosphere at a temperature of 800° C. or lower
Implementation Method 3
removing an oxide from the contaminated or damaged portion of the substrate using plasma etching
Implementation Method 4
supply gas to the internal space of the chamber to remove an oxide from the contaminated or damaged portion of the substrate
Implementation Method 5
removing a surface layer of the contaminated or damaged portion using a halogen-based gas
Data Source
AI summary
A precleaning apparatus includes a chamber having an internal space in which a substrate is cleaned, a substrate support disposed in the chamber and configured to support the substrate, a plasma generation unit disposed in the chamber and configured to generate plasma gas, a heating unit configured to heat the substrate on the substrate support, a cleaning gas supply unit configured to supply gas for oxide etching to the internal space of the chamber, and a hydrogen gas supply unit configured to supply hydrogen gas to the internal space of the chamber.