Segmented Nozzle for Thermal Expansion in Heat Treatment
Solution Overview
Problem
In vertically installed heat treatment apparatuses, forming a nozzle with high accuracy using SiC is challenging, leading to potential interference and damage due to thermal expansion when attached to a quartz adaptor.
Innovation Solution
A nozzle with two portions, one made of quartz and the other of silicon carbide, is connected to the adaptor, where the quartz portion has a lower coefficient of thermal expansion, reducing the likelihood of damage and improving accuracy by using a socket-and-spigot configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the nozzle is formed of SiC to enable high-temperature treatment, then the nozzle can withstand temperatures higher than 1200°C, but the nozzle becomes damaged due to thermal expansion and cannot be attached directly to the quartz adaptor
Solution Approach 1:
The nozzle is divided into two distinct portions: a first portion made of quartz that connects to the adaptor, and a second portion made of SiC that withstands high temperatures. This segmentation allows each material to perform its optimal function while avoiding the thermal expansion compatibility issue between SiC and quartz adaptor.
Solution Approach 2:
The nozzle is constructed as a composite structure combining quartz and SiC materials. The quartz portion provides thermal expansion compatibility with the quartz adaptor, while the SiC portion provides high-temperature resistance, creating a composite nozzle that overcomes the limitations of using either material alone.
2Manufacturing precision
If the nozzle is formed of SiC with high accuracy, then the nozzle precision is improved, but it is difficult to form the nozzle at a high degree of accuracy and the nozzle may interfere with the boat or substrate
Solution Approach 1:
The nozzle is segmented into a quartz first portion and a SiC second portion. The quartz portion can be manufactured with high precision using conventional techniques, while the SiC portion can be formed by CVD with controlled geometry. This segmentation makes high-precision manufacturing feasible by combining materials that are each easier to precision-manufacture than a monolithic SiC nozzle.
3Ease of operation
If the clearance between the nozzle and boat is made large to prevent interference, then the interference is avoided, but the nozzle cannot be formed of SiC attached directly to the quartz adaptor
Solution Approach 1:
The segmented nozzle structure with quartz first portion and SiC second portion allows for proper clearance design between the nozzle and boat while maintaining reliable attachment to the quartz adaptor. The quartz-to-quartz interface ensures thermal expansion compatibility, eliminating the reliability issue even when clearances are optimized for operational safety.
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 enhances the nozzle's stability and accuracy, preventing interference and damage from thermal expansion, while allowing for efficient gas flow and uniform temperature distribution during high-temperature treatments.
Implementation Method 1
the first portion is formed of a material having the equal coefficient of thermal expansion as the adapter
Implementation Method 2
a heater provided outside the reaction tube for heating the interior of the reaction tube, so that the heater heats up the interior of the reaction tube to a high temperature
Implementation Method 3
the first portion of the nozzle is adapted to allow gas to flow in a direction different from the vertical direction, and the second portion of the nozzle is adapted to allow gas to flow in the vertical direction
Data Source
AI summary
A heat treatment apparatus wherein a nozzle is accurately provided on an adaptor to prevent the nozzle from interfering with other part items and a possibility of breakage due to heat expansion of the nozzle can be reduced. The heat treatment apparatus (10) is provided with a reaction tube (42) for treating a substrate (54), a quartz adaptor (44) for supporting the reaction tube (42), a nozzle (66) connected to the adaptor (44) for supplying a treatment gas into the reaction tube (42), and a heater (46) provided outside the reaction tube (42) for heating inside the reaction tube (42). The nozzle (66) is connected to an upper plane of the adaptor (44) in the reaction tube (42) at least a part which is of the nozzle (66) and is connected with the adaptor (44) is made of quartz and other nozzle parts are made of silicon carbide.