Load-Lock Chamber Gas Flow Control for Wafer Contamination
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Solution Overview
Problem
Load-lock type CVD apparatuses face issues with foreign contaminants and particles entering the processing chamber, leading to reduced production yield due to inadequate placement of vacuum exhaust and purge gas supply ports, causing contamination and particle floatation during pressure changes.
Innovation Solution
The apparatus includes a substrate treating system with a processing chamber, a preliminary chamber, a substrate holding jig mechanism, an inert gas supply port, a first exhaust port positioned higher than the gas supply port, and a second vacuum exhaust port, with a controller managing the gas flow to prevent contamination by directing inert gas flow upwards and maintaining specified pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the vacuum exhaust port and purge gas supply port are placed in the standby chamber without considering their positions, then the apparatus structure is simple, but foreign contaminants and particles enter the processing chamber causing contamination
Solution Approach 1:
The patent applies local quality by positioning the inert gas supply port at a lower location and the exhaust port at an upper location within the standby chamber. This creates a localized upward gas flow pattern specifically in the region where contaminants and particles may accumulate, ensuring that the gas flow direction is optimized for contaminant removal without requiring complex overall system redesign.
Solution Approach 2:
The patent inverts the conventional approach by supplying inert gas from the lower position and exhausting from the upper position, creating an upward flow pattern. This inverted configuration ensures that gas flow moves from the region where contaminants accumulate (lower area) toward the exhaust port (upper area), effectively preventing contaminant migration to the processing chamber.
2Object-affected harmful factors
If the inert gas supply port is positioned at a higher location, then the exhaust structure is simpler, but particles sunk at the bottom of the standby chamber float upwards and enter the processing chamber
Solution Approach 1:
The patent creates a localized upward gas flow in the lower region of the standby chamber by positioning the inert gas supply port below the substrate holding area. This localized flow pattern specifically addresses the particle floatation problem at the bottom without creating unwanted flow patterns in other regions, maintaining simplicity while solving the contamination issue.
3Productivity
If the exhaust port is positioned to allow easy exhaust flow, then the exhaust efficiency is improved, but foreign contaminants from the boat elevator enter the processing chamber
Solution Approach 1:
The patent positions the exhaust port at an upper location within the standby chamber, creating a localized exhaust zone that efficiently captures and removes contaminants and particles. This positioning ensures that the exhaust flow path is optimized for contaminant removal while the inert gas supply from below maintains a protective upward flow that prevents contaminant migration to the processing chamber.
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 effectively exhausts foreign contaminants and prevents particle floatation, maintaining the cleanliness of wafers and the processing chamber, thereby improving the production yield of the film-forming process in IC manufacturing.
Implementation Method 1
inert gas supplied from the inert gas supply port flows from below the substrate holding area to higher than the substrate holding area
Implementation Method 2
a first exhaust port for exhausting the inert gas and provided in the preliminary chamber at a position higher than the substrate holding area
Implementation Method 3
a second exhaust port for drawing a vacuum in the preliminary chamber
Implementation Method 4
inert gas supplied from the inert gas supply port flows from below the substrate holding area to higher than the substrate holding area, and is exhausted from the first exhaust port... Foreign contaminants emitted from the mechanism can therefore be exhausted from the vent exhaust port
Data Source
AI summary
A gas flow in a load-lock type preliminary chamber is improved. A load-lock type substrate treating apparatus contains a processing chamber (34) for storing and processing a substrate (1); a preliminary chamber (23) continuously arranged to the processing chamber (31); a substrate holding jig mechanism (40) for carrying in and carrying out a substrate holding jig (50) holding multiple substrates (1), to and from the processing chamber (31); an inert gas supply port (61) for supplying inert gas to the preliminary chamber (23); a first exhaust port (71) provided above the inert gas supply port (61) in the preliminary chamber (23) to exhaust the inert gas: a second exhaust port (81) to draw a vacuum in the preliminary chamber (23); and a controller (100) for performing control so that the inert gas supplied from the inert gas supply port (61) is exhausted only from the first exhaust port (71), while maintaining the preliminary chamber (23) drawn a vacuum from the second exhaust port (81) at a specified pressure after raising the pressure.