Rotating Substrate Laser Anneal Thermal Processing
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Solution Overview
Problem
Current rapid thermal processing (RTP) chambers using lamp heat sources have a time constant that is too large, leading to inefficient annealing and significant dopant diffusion, making it challenging to align dopants within the crystal matrix of semiconductor substrates without overheating or over-exposing the target zone, especially as device sizes decrease.
Innovation Solution
The apparatus incorporates a combination of a radiant heat source and a laser source with a reflector plate having apertures to modulate laser radiation, allowing for flash on spike annealing processes, which enables precise temperature control and rapid heat dissipation, thereby reducing thermal diffusion and achieving uniform annealing across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If lamp heat sources are used in RTP chambers, then the substrate can be heated to required temperatures, but the time constant is too large causing significant dopant diffusion and inefficient annealing
Solution Approach 1:
The patent changes the heating mechanism from conventional lamp-based thermal radiation to direct laser irradiation, fundamentally altering the heating parameters. The laser source provides rapid, localized heating with a much shorter time constant, enabling the substrate to reach required temperatures quickly while minimizing dopant diffusion during the annealing process.
Solution Approach 2:
The patent replaces the mechanical lamp heating system with a laser-based optical system. This substitution eliminates the thermal inertia inherent in lamp-based systems, providing faster response time and more precise temperature control during annealing, thereby reducing the time constant and preventing dopant diffusion.
2Manufacturing precision
If more heat is applied or heat is applied for longer time to align dopants in the crystal matrix, then annealing effectiveness improves, but dopant atoms move beyond the desired zone of occupation
Solution Approach 1:
The patent employs periodic or pulsed laser action to deliver heat in controlled bursts rather than continuous exposure. This periodic heating allows the substrate to reach necessary temperatures for dopant alignment while providing brief, controlled exposure times that prevent excessive thermal diffusion of dopant atoms beyond the target zone.
Solution Approach 2:
The laser source provides localized heating precisely where needed on the substrate surface, concentrating thermal energy in the specific regions requiring annealing. This local quality approach ensures that dopant alignment occurs in the target zone without subjecting the entire substrate to prolonged heating, thereby minimizing unwanted dopant diffusion to adjacent areas.
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 enables rapid and uniform thermal processing, allowing for precise control of dopant alignment and temperature management, reducing unwanted diffusion and improving the effectiveness of annealing processes, even at higher temperatures and smaller target zones.
Implementation Method 1
nanosecond anneals utilizing megawatt lasers
Implementation Method 2
radiant heat source 106 disposed in an inside diameter of the substrate support 104
Implementation Method 3
A rotatable support may be disposed within the interior volume adjacent the radiant heat source
Implementation Method 4
The window 114 made from a material transparent to heat and light of various wavelengths may be used to shield the radiant heat source 106 from the processing environment while allowing the radiant heat source 106 to heat the substrate 140
Data Source
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AI summary
Embodiments of the present disclosure relate to thermal processing of substrates. More specifically, embodiments described herein relate to flash on spike annealing processes and apparatus suitable for performing such processes. In one embodiment, a thermal processing apparatus may include a lamp radiation source, a laser source, and a reflector plate disposed between the lamp radiation source and the laser source. One or more apertures may be formed in the reflector plate and the laser source may be positioned adjacent to the reflector plate such that a laser beam emitted from the laser source propagates through the one or more apertures. In one embodiment, the reflector plate may be substantially circular and the one or more apertures may approximate a sector of the reflector plate.