Flash Annealing Wafer Temperature Verification Before Irradiation
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Solution Overview
Problem
Existing flash lamp annealing processes face issues where the semiconductor wafer temperature does not reach the target temperature due to factors like warpage or hardware abnormalities, leading to yield reductions and device property abnormalities that are only detected later, causing time inefficiencies.
Innovation Solution
A method and apparatus that utilize a continuous lighting lamp for preheating, followed by flash lamp irradiation, with temperature monitoring and comparison to a target temperature, stopping the flash irradiation if the temperature is outside the allowable range, and adjusting the process to prevent issues from non-target temperature treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If flash irradiation is performed without verifying target temperature is reached, then processing time is reduced, but device properties become abnormal and yield decreases
Solution Approach 1:
The patent applies preliminary action by measuring the substrate temperature before flash irradiation and comparing it to the target temperature. This preliminary verification ensures the substrate is properly preheated, preventing abnormal device properties while maintaining efficient processing. The temperature check is performed as a prerequisite step before the main flash irradiation process.
2Reliability
If temperature monitoring and verification steps are added, then device property reliability improves, but process time increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring the substrate temperature during preheating, comparing the measured temperature to the target temperature, and using this information to determine when to proceed with flash irradiation. This feedback mechanism ensures reliable device properties while minimizing process time by automatically proceeding when temperature criteria are met.
3Productivity
If flash irradiation is performed on substrate at non-target temperature, then productivity is maintained, but thermal history variability increases causing yield reduction
Solution Approach 1:
The patent ensures thermal history consistency by performing preliminary temperature verification before flash irradiation. The substrate temperature is measured and confirmed to match the target temperature, ensuring consistent thermal conditions for all substrates undergoing flash irradiation, thereby maintaining both productivity and manufacturing 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
Prevents problems from flash irradiation on substrates that haven't reached the target temperature, ensuring consistent treatment outcomes and reducing thermal history variability.
Implementation Method 1
irradiating a substrate received in a chamber with light from a continuous lighting lamp to preheat the substrate
Implementation Method 2
irradiating a front surface of the substrate with a flash of light from a flash lamp to increase the temperature of the front surface of the substrate
Implementation Method 3
a measured temperature of the substrate which is measured by a radiation thermometer
Data Source
AI summary
A semiconductor wafer transported into a chamber is preheated by halogen lamps. A comparison is made between a target temperature for the preheating and a measured temperature of the semiconductor wafer which is measured by a radiation thermometer immediately before flash irradiation and in the final stage of the preheating using the halogen lamps. Then, when the measured temperature of the semiconductor wafer is outside an allowable range for the preset target temperature, an alarm is issued, and the treatment of the semiconductor wafer being treated is stopped without the flash irradiation. On the other hand, when the measured temperature of the semiconductor wafer is within the allowable range, the flash irradiation process is performed on the semiconductor wafer.