Cap Cover Purge Gas Redirection for Furnace Opening Adhesion
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Solution Overview
Problem
In vertical type substrate processing apparatuses, the flow of purge gas towards the substrate can lead to non-uniform film formation and reduced productivity due to adhesion of by-products at the furnace opening portion, affecting the film-forming uniformity on the substrate surface.
Innovation Solution
A substrate processing apparatus design featuring a cap with a concentric cylinder shape and a cap cover that directs purge gas flow away from the substrate, preventing adhesion of by-products at the furnace opening and maintaining film-forming uniformity by circulating the purge gas through a specific flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If purge gas is supplied to protect the magnetic fluid seal, then the seal is protected from reactive gas, but the purge gas flows upward and deteriorates film-forming uniformity on the substrate surface
Solution Approach 1:
The cap cover acts as an intermediary component that intercepts the upward-flowing purge gas and redirects it through a designated flow path (spaces between shaft-cylindrical portion and upper plate-cap cover) away from the substrate, thereby mediating between the seal protection function and the film-forming quality requirement
Solution Approach 2:
The invention changes the flow direction of purge gas from the vertical dimension (upward along the shaft) to horizontal/directional flow through the cap cover's flow path, diverting it away from the substrate region and preventing interference with film formation
2Reliability
If purge gas flows upward along the shaft, then the magnetic fluid seal is protected, but by-products adhere to the furnace opening portion and productivity is reduced
Solution Approach 1:
The cap cover serves as a mediator that captures purge gas containing by-products and redirects it through a controlled flow path, preventing direct contact between the purge gas and the furnace opening portion, thus maintaining productivity while preserving seal protection
3Reliability
If a conventional cap structure is used, then the reaction vessel is sealed, but the purge gas directly contacts the substrate region causing non-uniform film formation
Solution Approach 1:
The cap structure is segmented into distinct functional zones: the cap body for sealing, the cap cover for flow control, and the defined flow path spaces for gas redirection. This segmentation allows simultaneous achievement of sealing and purge gas flow management
Solution Approach 2:
The cap cover and its associated flow path spaces act as an intermediary system between the sealed reaction vessel and the substrate region, controlling purge gas flow to protect the substrate from direct exposure while maintaining the sealing function
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 design effectively suppresses the adhesion of by-products to the furnace opening while maintaining film-forming uniformity, enhancing substrate processing productivity and efficiency.
Implementation Method 1
a sealing part such as a magnetic fluid seal
Implementation Method 2
a purge gas supplied to vicinity of the shaft from thereunder flows sequentially to a space between the shaft and the cylindrical portion
Data Source
AI summary
Described herein is a technique capable of suppressing adhesion of by-products to a furnace opening portion. A substrate processing apparatus includes: a reaction vessel having an opening at a lower end and accommodating a substrate retainer; a shaft rotatably supporting the substrate retainer; a cap including: a side surface portion having a predetermined gap with an inner surface of the reaction vessel; a cylindrical portion through which the shaft is inserted; an upper plate portion of an annular shape; and a flange connected to a lower end of the side surface portion; and a cap cover connected to the shaft above the upper end of the cylindrical portion. A purge gas from thereunder flows sequentially to a space between the shaft and the cylindrical portion, a space between the upper plate portion and the cap cover and a space between the side surface portion and the cap cover.