Heat-Shield Plate for Substrate Processing Apparatus
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Solution Overview
Problem
Existing selective epitaxy processes face challenges in maintaining selectivity due to uncontrolled reaction rates and thermal issues, leading to unsuitable high temperatures that cause nitridation and thermal damage on substrates, and require precise control of chemical concentrations and temperatures.
Innovation Solution
A substrate processing apparatus with a heat-shield plate is used to prevent heat from entering the lower chamber and reaction gas from being deposited on it, featuring a heater outside the external reaction tube, supply and exhaust nozzles, and a substrate holder that moves between stacking and process positions, with the heat-shield plate closing the lower side of the internal reaction tube to maintain a controlled environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high reaction temperature (about 800°C or more) is used for selective epitaxy process, then deposition reaction rate is improved, but thermal damage and uncontrolled nitridation reaction occur on substrate surface
Solution Approach 1:
The reaction chamber is divided into two separate chambers: a first reaction chamber for performing the deposition reaction at high temperature, and a second reaction chamber for performing the etching reaction at low temperature. This segmentation allows independent temperature control in each chamber, enabling high deposition rates without thermal damage to the substrate.
Solution Approach 2:
A showerhead is introduced as an intermediary component that supplies reaction gases uniformly across the substrate surface. The showerhead design ensures that reaction gases are distributed evenly, enabling precise control of the deposition process and preventing localized thermal damage while maintaining high overall deposition rates.
2Manufacturing precision
If chemical concentration and reaction temperature are adjusted to maintain selectivity, then epitaxial layer quality is improved, but process control complexity increases
Solution Approach 1:
By segmenting the reaction process into two separate chambers with independent temperature control, the system simplifies process control. Each chamber can be optimized independently for its specific reaction type, reducing the complexity of coordinating multiple parameters in a single chamber while maintaining high epitaxial layer quality.
Solution Approach 2:
The system incorporates feedback control mechanisms that monitor reaction conditions and automatically adjust gas flow rates and temperatures. This feedback system maintains precise control over chemical concentrations and reaction temperatures, ensuring consistent epitaxial layer quality without requiring complex manual intervention.
3Reliability
If insufficient silicon precursor is supplied, then etching reaction is activated to maintain selectivity, but whole process rate decreases
Solution Approach 1:
The segmentation of deposition and etching reactions into separate chambers allows each reaction to proceed at its optimal rate without compromising the other. The deposition chamber can use sufficient silicon precursor to maintain high deposition rates, while the etching chamber independently controls selectivity, eliminating the trade-off between selectivity and process rate.
4Reliability
If insufficient corrosive solution precursor is supplied, then selectivity for forming single crystalline and polycrystalline materials is reduced, but deposition reaction efficiency decreases
Solution Approach 1:
By separating the deposition and etching reactions into different chambers, the system can independently optimize precursor supply for each reaction type. The deposition chamber receives sufficient corrosive solution precursor to maintain high deposition efficiency, while the etching chamber independently ensures selectivity, eliminating the compromise between efficiency and selectivity.
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 setup allows for controlled epitaxial layer formation by maintaining a stable temperature and preventing heat loss, ensuring precise control over the epitaxial process and reducing thermal damage, thereby improving manufacturing yield and substrate quality.
Implementation Method 1
a heater disposed outside the external reaction tube to heat the process space
Implementation Method 2
a heat-shield plate disposed under the substrate holder to close an opened lower side of the internal reaction tube
Implementation Method 3
the substrate holder on which the one or more substrates are vertically stacked, the substrate holder being movable between a stacking position and a process position
Data Source
AI summary
Provided is a substrate processing apparatus. The substrate processing apparatus in which processes with respect to substrates are performed includes a lower chamber having an opened upper side, the lower chamber including a passage allowing the substrates to pass therethrough in a side thereof, an external reaction tube closing the opened upper side of the lower chamber to provide a process space in which the processes are performed, an internal reaction tube disposed within the external reaction tube, the internal reaction tube being disposed around a substrate holder placed in the process position to define a reaction region with respect to the substrates, a heater disposed outside the external reaction tube to heat the process space, the substrate holder on which the one or more substrates are vertically stacked, the substrate holder being movable between a stacking position in which the substrates are stacked within the substrate holder and a process position in which the processes with respect to the substrates are performed, and a heat-shield plate disposed under the substrate holder to close an opened lower side of the internal reaction tube when the substrate holder is disposed at the process position.