Vertical Substrate Processing Apparatus Gas Flow Uniformity
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Solution Overview
Problem
In vertical type substrate processing apparatuses, the non-uniform velocity distribution of process gas among wafers leads to varying degrees of gas decomposition and film thickness differences between upper and lower wafers due to significant pressure loss on the exhaust side.
Innovation Solution
A substrate processing apparatus with a reaction tube and cylindrical portion configuration that includes a gas supply part, first and second gas exhaust ports, and a nozzle arrangement chamber to minimize pressure loss and ensure uniform gas velocity distribution across wafers, featuring a closed upper end reaction tube, concentric cylindrical portion, and strategically placed gas supply and exhaust ports to manage gas flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vertical type apparatus with multiple wafers is used, then productivity is improved by batch processing multiple substrates, but manufacturing precision deteriorates due to non-uniform gas velocity distribution and pressure loss causing film thickness variations
Solution Approach 1:
The reaction tube is divided into multiple independent processing zones, each with its own gas supply and exhaust ports. This segmentation allows each zone to maintain uniform pressure and gas velocity distribution independently, eliminating the cumulative pressure loss effect that causes film thickness variations across multiple wafers while preserving batch processing capability
Solution Approach 2:
Different regions of the reaction tube are equipped with locally optimized gas supply and exhaust ports positioned at specific heights and angles. This local quality approach ensures that each wafer processing zone receives gas with appropriate velocity and pressure characteristics, maintaining film thickness uniformity across all wafers processed simultaneously
2Device complexity
If gas is supplied from the bottom of the reaction tube, then device complexity is reduced by simplifying the gas supply structure, but manufacturing precision deteriorates due to non-uniform gas velocity distribution among wafers
Solution Approach 1:
The gas supply system is segmented into multiple independent supply ports distributed at different heights and positions within the reaction tube. Each port serves a specific wafer zone, ensuring uniform gas velocity distribution without requiring complex centralized control mechanisms
Solution Approach 2:
The gas supply approach transitions from a single bottom-up vertical flow to a multi-dimensional distribution pattern with ports positioned at various heights and radial locations. This dimensional expansion creates uniform gas velocity fields across different wafer planes while maintaining relatively simple port structures
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 configuration minimizes pressure loss, enhances gas flow velocity uniformity, and mitigates film thickness variations between wafers, improving processing efficiency and consistency.
Implementation Method 1
a gas supply part provided in an annular gap between the reaction tube and the cylindrical portion along an extending direction of the gap, and configured to supply a process gas into the process chamber
Implementation Method 2
a pressure loss on an exhaust side (downstream side of the plurality of the wafers) in the reaction tube may be large
Implementation Method 3
decomposition of the process gas may be accelerated to different degrees among the plurality of the wafers
Implementation Method 4
decomposition of the process gas may be accelerated to different degrees among the plurality of the wafers. Therefore, due to a difference in the decomposition degree of the process gas while passing through the plurality of the wafers, a difference in film thickness formed on the plurality of the wafers may occur
Data Source
AI summary
According to one aspect of the technique of the present disclosure, there is provided a substrate processing apparatus including: a reaction tube; a substrate retainer; a cylindrical portion provided inside the reaction tube and concentric with the reaction tube and comprising a process chamber; a gas supply part in an annular gap between the reaction tube and the cylindrical portion; a gas supply port through which the gas supply part communicates with the process chamber; a first gas exhaust port provided at the cylindrical portion, through which the gap communicates with the process chamber; an outlet connected to the reaction tube at a location lower than the first gas exhaust port and opposite to the gas supply port; and a second gas exhaust port provided at the cylindrical portion at a location lower than the first gas exhaust port and aligned with a same orientation as the outlet.