Fiber Laser Substrate Processing with Pulse Control
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Solution Overview
Problem
Current rapid thermal processing systems in the semiconductor industry face limitations in rapidly heating substrates due to constraints on the rate of high-intensity light source activation and termination, which restrict processing times to above 50 nsec to 100 μs, necessitating a system and method for independent control of light pulse duration, shape, and repetition rate.
Innovation Solution
The use of fiber lasers to generate optical pulses with selectable durations between 100 ns and 100 μs, repetition rates less than 1 MHz, and adjustable intensity, combined with an optical pyrometry assembly for monitoring, allows for precise control and efficient heating of semiconductor substrates, enabling processes like film formation, dopant activation, and annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional high intensity lamps are used for rapid thermal processing, then substrate heating can be achieved, but the rate of light source activation and termination is limited, restricting processing time to above 50 nsec to 100 μs
Solution Approach 1:
The patent transitions from traditional lamp-based heating to laser-based heating, fundamentally changing the energy source parameter. Lasers provide much faster activation and termination rates compared to lamps, enabling processing times between 50 nsec and 100 μs while achieving the required substrate heating rates.
Solution Approach 2:
The patent replaces the mechanical/electrical lamp heating system with an optical laser system. This substitution enables precise control of pulse duration and intensity, achieving faster response times and better control over the heating process without the limitations of traditional lamp activation and termination rates.
2Adaptability or versatility
If traditional lamps are used, then substrate heating is possible, but independent control of light pulse duration, shape, and repetition rate is restricted
Solution Approach 1:
The patent implements dynamic control of laser parameters including pulse duration, shape, and repetition rate. The laser system can be rapidly tuned to provide different pulse configurations independently, allowing adaptation to various processing requirements without being constrained by fixed lamp characteristics.
Solution Approach 2:
The laser-based system provides multiple functions through a single light source, including precise pulse duration control, variable pulse shapes, and adjustable repetition rates. This universal control capability replaces the need for multiple specialized lamp systems, achieving versatility without proportionally increasing overall system complexity.
3Productivity
If shorter pulse durations are used to meet processing time targets, then processing speed improves, but control of initiation and termination as well as duration and repetition rate becomes more difficult
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor laser pulse characteristics and adjust parameters in real-time. This feedback system ensures precise control of pulse initiation, termination, duration, and repetition rate even at the short 50 nsec to 100 μs timescales required for high productivity.
Solution Approach 2:
The laser system is pre-configured with programmable control capabilities that allow precise timing and pulse parameter settings to be established before processing begins. This preliminary programming enables automatic, repeatable control of short pulses without requiring complex real-time manual adjustment during operation.
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 precise substrate processing, allowing for efficient heating and chemical reactions on a semiconductor substrate, overcoming the limitations of traditional systems by providing flexible pulse control and improved processing times.
Implementation Method 1
one or more fiber lasers that generate optical pulses to heat a portion of a surface of the semiconductor substrate
Implementation Method 2
The optical pulses can promote chemical reactions which result in the formation of a film on a surface of the semiconductor substrate
Implementation Method 3
Alternatively, the optical pulses can activate dopants in the semiconductor substrate
Implementation Method 4
Alternatively, the optical pulses can anneal the semiconductor substrate
Implementation Method 5
The optical pulses can be used to modify the semiconductor substrate by heating the semiconductor substrate or diffusing atoms in the semiconductor substrate
Implementation Method 6
an optical pyrometry assembly to monitor radiation from the portion of the surface near a wavelength different from the one or more wavelengths of the one or more fiber lasers
Data Source
AI summary
Embodiments of the present invention pertain to substrate processing equipment and methods incorporating light sources which provide independent control of light pulse duration, shape and repetition rate. Embodiments further provide rapid increases and decreases in intensity of illumination.