Dummy Wafer Wear Tracking for Flash Lamp Annealing
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Solution Overview
Problem
The existing methods for managing dummy wafers in flash lamp annealing processes are inadequate, leading to deterioration, cracking, and warpage, which results in contamination and transport issues due to insufficient monitoring of their condition.
Innovation Solution
A method that calculates a wear-and-tear value by measuring temperature, electric power, discharge voltages, or surface temperature of dummy wafers during heating and issues an alarm when the value exceeds a predetermined threshold, allowing for timely replacement and preventing erroneous treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If dummy wafers are repeatedly subjected to heating treatment for dummy running, then the temperature of in-chamber structures reaches stable temperature, but deterioration of dummy wafers progresses causing cracking and warpage
Solution Approach 1:
The system performs preliminary heating treatment on dummy wafers before actual wafer processing to preheat in-chamber structures. This preliminary action stabilizes the thermal environment for subsequent processing while managing dummy wafer exposure through tracking and alarm mechanisms.
Solution Approach 2:
The system tracks the cumulative heating exposure of dummy wafers by calculating wear-and-tear values based on temperature and time data. When the wear-and-tear value reaches a threshold, an alarm is triggered to prevent further deterioration, creating a feedback loop that manages dummy wafer reliability.
2Ease of operation
If operator manually tracks dummy wafer treatment history, then replacement can be scheduled, but accurate grasping of deterioration condition is insufficient leading to accidental treatment of deteriorated wafers
Solution Approach 1:
The system replaces manual mechanical tracking with an automated computer-based system that calculates wear-and-tear values using temperature and time data. This substitution eliminates human error in monitoring while maintaining operational simplicity through automated alerts.
Solution Approach 2:
The system introduces a computer-based intermediary that processes temperature and time data to calculate wear-and-tear values. This intermediary provides precise measurement and objective assessment of dummy wafer deterioration conditions, replacing subjective manual tracking.
3Productivity
If flash heating treatment is performed on dummy wafers to stabilize in-chamber structure temperature, then processing conditions are optimized, but contamination and transport troubles occur due to dummy wafer deterioration
Solution Approach 1:
The system performs preliminary heating treatment on dummy wafers to stabilize in-chamber structures before actual wafer processing. This preliminary action optimizes processing conditions while the wear-and-tear tracking system prevents excessive dummy wafer deterioration that would cause contamination.
Solution Approach 2:
The system monitors dummy wafer deterioration through wear-and-tear value calculation and triggers replacement when thresholds are exceeded. This ensures that deteriorated dummy wafers are discarded before they cause contamination, while functional dummy wafers are recovered and reused for continued dummy running.
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 effectively manages dummy wafer deterioration, ensuring reliable identification of advanced deterioration and preventing accidents during the heat treatment process.
Implementation Method 1
measuring a temperature of the dummy wafer when the dummy wafer is heated by irradiation with light from a continuous lighting lamp
Implementation Method 2
flash heating treatment is performed on dummy wafers... irradiation of a surface of a semiconductor wafer implanted with impurities by an ion implantation process with a flash of light emitted from flash lamps
Implementation Method 3
measuring a temperature of the dummy wafer... measuring a front surface temperature of the dummy wafer
Data Source
AI summary
Dummy running is carried out which performs preheating treatment using halogen lamps and flash heating treatment using flash lamps on a dummy wafer to control the temperature of in-chamber structures including a susceptor and the like. In this process, a wear-and-tear value is calculated by adding up the amounts of electric power inputted to the halogen lamps or the like each time the preheating treatment or the flash heating treatment is performed. The wear-and-tear value is an indicator indicating the degree of deterioration of the dummy wafer. If the wear-and-tear value of the dummy wafer is not less than a predetermined threshold value, an alarm is issued. This allows an operator of a heat treatment apparatus to recognize that the deterioration of the dummy wafer reaches a limit value and to reliably grasp the dummy wafer suffering advanced deterioration.