Flash Lamp Annealing Wafer Jump Detection via Temperature Profiling
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Solution Overview
Problem
The existing flash lamp annealing process for semiconductor wafers causes thermal expansion and deformation, leading to wafer vibration and potential cracking or misalignment, which complicates transport and increases costs due to the need for costly imaging mechanisms for behavior monitoring.
Innovation Solution
A method and apparatus that irradiate the semiconductor wafer with a flash of light, measure the temperature profile, and analyze the behavior based on the temperature data to prevent transport issues by stopping the wafer transport when a predetermined jump distance threshold is exceeded, eliminating the need for costly imaging mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flash lamp annealing is used to rapidly heat the semiconductor wafer surface, then impurity activation is achieved without deep diffusion, but thermal expansion causes wafer deformation and vibration
Solution Approach 1:
The patent changes the physical parameters of the heating process by using flash lamp annealing with extremely short duration (microseconds to milliseconds) and high intensity, achieving rapid surface heating that activates impurities without allowing time for deep thermal diffusion, thus controlling junction depth while minimizing overall thermal expansion
Solution Approach 2:
The patent employs periodic flash lamp irradiation to heat the wafer surface in extremely short pulses, creating rapid temperature cycles that achieve impurity activation before significant thermal diffusion can occur, thereby controlling the heating process to balance between activation and deformation
2Manufacturing precision
If flash lamp annealing is used to rapidly heat the semiconductor wafer surface, then impurity activation is achieved without deep diffusion, but wafer vibration and cracking occur
Solution Approach 1:
The patent introduces a support structure with multiple support points that are positioned in advance to provide mechanical support to the wafer during flash lamp annealing, preventing excessive vibration and cracking caused by rapid thermal expansion while allowing the flash heating process to proceed for impurity activation
Solution Approach 2:
The patent employs a support structure that acts as a cushioning mechanism, absorbing and distributing the mechanical stress from rapid thermal expansion before it can cause wafer cracking or excessive vibration, thereby protecting wafer integrity during the flash lamp annealing process
3Measurement precision
If costly imaging mechanisms are used to monitor wafer behavior, then wafer vibration and jumping can be detected, but device complexity and cost increase
Solution Approach 1:
The patent makes the wafer itself serve as the monitoring element by incorporating temperature sensors directly into the wafer or wafer support structure, allowing the wafer to provide its own behavioral data during flash lamp annealing, thereby eliminating the need for separate costly imaging mechanisms
Solution Approach 2:
The patent replaces complex mechanical imaging systems with simpler optical or electrical sensing methods, such as using temperature sensors or optical interferometry to detect wafer behavior, thereby reducing device complexity and cost while maintaining measurement precision
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 allows for simplified monitoring of the semiconductor wafer's behavior during flash irradiation, preventing transport troubles and reducing costs by using temperature profiling to assess and manage the wafer's movement effectively.
Implementation Method 1
irradiating a front surface of a substrate supported by a susceptor in a chamber with a flash of light from a flash lamp
Implementation Method 2
The xenon flash lamps have a spectral distribution of radiation ranging from ultraviolet to near-infrared regions
Implementation Method 3
measuring a temperature of the front surface of the substrate at least after the irradiation with the flash of light
Implementation Method 4
This causes abrupt thermal expansion only near the front surface of the semiconductor wafer, so that the semiconductor wafer becomes deformed abruptly
Data Source
AI summary
A front surface of a semiconductor wafer is momentarily heated by irradiation with a flash of light from flash lamps. An upper radiation thermometer and a high-speed radiation thermometer unit measure a temperature of the front surface of the semiconductor wafer after the irradiation with the flash of light. The temperature data are sequentially accumulated, so that a temperature profile is acquired. An analyzer determines the highest measurement temperature of the semiconductor wafer subjected to the flash irradiation from the temperature profile to calculate a jump distance of the semiconductor wafer from a susceptor, based on the highest measurement temperature. If the calculated jump distance is greater than a predetermined threshold value, there is a high probability that the semiconductor wafer is significantly out of position, so that the transport of the semiconductor wafer to the outside is stopped.