Adjustable Process Chamber Height for Uniform Semiconductor Layer Thickness
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Solution Overview
Problem
In multi-process-chamber reactors, variations in process chamber height lead to differences in layer growth rates, making it challenging to achieve identical layer thicknesses across substrates, as the growth rate is influenced not only by gas composition and concentration but also by the chamber height.
Innovation Solution
Implementing a controller and actuator system that continuously measures layer thickness in each process chamber and adjusts the chamber height to maintain consistent growth rates across all chambers, ensuring identical layer thickness by lowering or raising the susceptor based on real-time measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the process chamber height is kept fixed for all chambers, then the device structure is simple and easy to operate, but the layer thickness varies across different chambers due to gradual differences
Solution Approach 1:
The process chamber height is made dynamically adjustable during the layer growth process. Each process chamber is equipped with an actuator that can independently adjust the height of the susceptor or process chamber ceiling, allowing the system to adapt to variations in growth rates across different chambers while maintaining uniform layer thickness.
Solution Approach 2:
A feedback control system is implemented where layer thickness is continuously or periodically measured in each process chamber during growth. The measured thickness information is fed back to a controller that automatically adjusts the process chamber height via actuators to compensate for growth rate variations, ensuring uniform layer thickness across all chambers.
2Manufacturing precision
If the process chamber height is adjusted to correct layer growth differences, then layer thickness uniformity is improved, but the process complexity and control difficulty increase
Solution Approach 1:
The system performs self-correction by automatically adjusting process chamber heights based on real-time layer thickness measurements. The controller autonomously determines the required height adjustments and actuates the appropriate chambers without requiring manual intervention, making the complex control process transparent and easy to operate.
Solution Approach 2:
Manual measurement and adjustment operations are replaced by an automated control system that uses optical or other non-contact sensing methods to measure layer thickness and electronically controls actuators to adjust chamber heights, reducing operational complexity while improving precision.
3Measurement precision
If continuous layer thickness measurement is implemented in each process chamber, then layer growth monitoring precision is improved, but the device complexity and cost increase
Solution Approach 1:
Instead of continuously measuring layer thickness in all chambers simultaneously, the system uses periodic measurements at strategically selected intervals and positions. This partial measurement approach provides sufficient information for effective feedback control while reducing the complexity and cost of the measurement system compared to full continuous monitoring of all chambers.
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 approach ensures that layers with the same thickness are deposited across all substrates by dynamically adjusting the process chamber height, thereby compensating for growth rate deviations and achieving uniform layer growth.
Implementation Method 1
the layer thickness is measured continuously or, in particular, at short intervals in each process chamber on at least one substrate... by means of an optical measuring device, as known from DE 10 2004 007 984 A1, namely with a photodiode array, which is arranged on the rear wall of a chamber of a gas inlet element, so that the optical path is through a gas outlet opening on the underside of the gas inlet element
Implementation Method 2
The height of the process chamber can be influenced in order to influence the growth parameters of the layers deposited there. This is done by means of actuators which can move the susceptor and an attached heater up and down
Implementation Method 3
Below the graphite susceptor is a heater to heat the susceptor to a process temperature
Implementation Method 4
A MOCVD process takes place in the process chambers... process gases are introduced into the process chamber through a shower-head-like process gas inlet element
Data Source
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AI summary
The invention relates to a method for precipitating at least one layer, in particular a semiconductor layer, respectively on a plurality of substrates (5), wherein a plurality of in particular identically designed process chambers (2) in a coating device (1) are supplied with process gases by a common gas supply apparatus (11), each being conducted into the process chamber (2) by a gas inlet member (3), in which one or more of the substrates (5) to be coated are present on a susceptor (4), wherein the process chamber height (H), defined by the distance between a process chamber ceiling (8) and a process chamber floor (9), is variable and has an effect on the growth rate of the layer. In order to disclose measures for ensuring that the layer thicknesses of the layers thus deposited are substantially identical on all substrates, the layer thickness is measured continuously or at in particular short intervals for at least one substrate (5) in each process chamber (2) while the layer is growing. The process chamber height (H) is varied by means of a controller (12) and an actuator (6), so that layers having the same layer thickness are deposited in the process chambers. The invention further relates to a device for depositing at least one layer, in particular a semiconductor layer.