Cyclone Airflow Control for Stable Wafer Rotation at Low Pressure
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Solution Overview
Problem
Low-pressure heat treatment devices face challenges in maintaining temperature uniformity and stable rotation of wafers during the annealing process due to differences in heating lamp functions, wafer-lamp parallelism, and local reactions within the chamber, which are exacerbated by the low-pressure environment.
Innovation Solution
An airflow control method for a low-pressure heat treatment device that includes arranging a pressure sensor to control the process gas pressure between 1 to 20 Torrs, controlling the cyclone gas flow rate between 0.5 to 1.5 L/min with ±0.2 L/min accuracy, and adjusting the flow to ensure the tray and semiconductor workpiece rotate synchronously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wafer rotation uses gas to suspend and drive rotation in normal pressure process, then the wafer can rotate during the process, but under low-pressure conditions (1 to 20 Torrs) the gas flotation and rotation stability deteriorates
Solution Approach 1:
The patent changes the operating pressure parameter from normal pressure to low pressure (1 to 20 Torrs) and adjusts the cyclone gas flow rate parameter to 0.5 to 1.5 L/min with ±0.2 L/min accuracy to achieve stable wafer rotation and suspension under low-pressure conditions for remote plasma oxidation and low-pressure free radical oxidation processes
2Manufacturing precision
If precise flow control of cyclone gas is implemented to maintain stable rotation, then temperature uniformity and process stability improve, but the device complexity and control precision requirements increase
Solution Approach 1:
The patent optimizes the cyclone gas flow rate parameter to a specific range (0.5 to 1.5 L/min) with controlled accuracy (±0.2 L/min), which achieves stable temperature uniformity and process stability without requiring excessively complex control systems
Solution Approach 2:
The patent implements a feedback control mechanism that monitors and adjusts the cyclone gas flow rate to maintain stable wafer rotation and temperature uniformity during the low-pressure heat treatment process
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 method stabilizes the rotation of the tray and wafer under low-pressure conditions, ensuring temperature uniformity and process stability by precisely controlling the airflow, which is critical for high-temperature annealing processes like remote plasma oxidation and low-pressure free radical oxidation.
Implementation Method 1
arranging a pressure sensor in a process chamber of the low-pressure heat treatment device, and controlling a pressure of process gas in the process chamber to be 1 to 20 Torrs
Implementation Method 2
controlling a flow rate of cyclone gas delivered toward a bottom surface of a tray of the low-pressure heat treatment device to be 0.5 to 1.5 L/min
Implementation Method 3
adjusting the flow rate of the cyclone gas so that the tray and a semiconductor workpiece placed on an upper surface of the tray rotate together
Data Source
AI summary
Provided is an airflow control method for an air flotation cyclone operation of a low-pressure heat treatment device, comprising: arranging a pressure sensor in a process chamber of the low-pressure heat treatment device, and controlling a pressure of process gas in the process chamber to be 1 to 20 Torrs; controlling a flow rate of cyclone gas delivered toward a bottom surface of a tray of the low-pressure heat treatment device to be 0.5 to 1.5 L/min by flow control, and controlling accuracy to be within ±0.2 L/min; and adjusting the flow rate of the cyclone gas so that the tray and a semiconductor workpiece placed on an upper surface of the tray rotate together.