Flash Lamp Annealing Preheat Sequence for Faster Chamber Stabilization
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Solution Overview
Problem
The existing flash lamp annealing process requires multiple dummy wafers for temperature stabilization, leading to increased costs and reduced production efficiency due to the need for extensive dummy running to achieve stable chamber temperatures.
Innovation Solution
A method involving sequential transportation of dummy wafers into a chamber, where the first group is heated to a high temperature using a continuous lighting lamp and then flashed with a xenon lamp, and the second group is heated to a lower temperature using a continuous lighting lamp, followed by flashing, to efficiently stabilize the chamber temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple dummy wafers are used for temperature stabilization, then the chamber temperature becomes stable, but the production efficiency decreases and costs increase
Solution Approach 1:
The dummy wafers are divided into two groups: first dummy wafers that are heated only by continuous lighting lamps, and second dummy wafers that are heated by both continuous lighting lamps and flash lamps. This segmentation allows different heating strategies to be applied to different subsets of dummy wafers, optimizing the temperature stabilization process while reducing the total number of dummy wafers needed.
Solution Approach 2:
The continuous lighting lamps are used to preheat the first dummy wafers before the flash lamps are activated. This preliminary heating action ensures that the in-chamber structures are already warm when the second dummy wafers are processed, reducing the overall time required for temperature stabilization and minimizing the number of dummy wafers needed.
2Stability of the object's composition
If multiple dummy wafers are used for temperature stabilization, then the chamber temperature becomes stable, but the time required for stabilization increases
Solution Approach 1:
The dummy wafers are divided into two groups with different heating protocols. The first dummy wafers are heated only by continuous lighting lamps, while the second dummy wafers receive both continuous and flash lamp heating. This segmentation enables parallel processing strategies that reduce the total stabilization time while maintaining temperature stability.
Solution Approach 2:
The heating process uses periodic alternation between continuous lighting lamp operation and flash lamp operation across the two groups of dummy wafers. This periodic action pattern allows the system to accumulate heat in the in-chamber structures more efficiently, reducing the overall stabilization time while maintaining temperature stability.
3Speed
If flash lamp annealing is used to heat the substrate surface rapidly, then the heating speed increases, but the temperature uniformity across different wafers in a lot decreases
Solution Approach 1:
The dummy wafers are segmented into two groups with different heating protocols. The first group is heated only by continuous lighting lamps, while the second group receives both continuous and flash lamp heating. This segmentation creates a temperature gradient that ensures uniform temperature distribution across all wafers in the lot, preventing temperature differences between initial and latter wafers.
Solution Approach 2:
The heating parameters are changed between the two groups of dummy wafers. The first group experiences lower heating intensity (continuous lighting only), while the second group experiences higher heating intensity (continuous lighting plus flash lamps). This parameter change strategy compensates for the temperature differences that would otherwise occur due to the warming of in-chamber structures, maintaining temperature uniformity across the lot.
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 reduces the number of dummy wafers needed for stabilization, shortening the stabilization time and maintaining a uniform temperature history for all wafers in a lot, thereby enhancing production efficiency and reducing costs.
Implementation Method 1
irradiating a back surface of dummy wafers with light from a continuous lighting lamp to heat the dummy wafers to a predetermined temperature
Implementation Method 2
irradiating a front surface of the dummy wafers with a flash of light from a flash lamp to heat the dummy wafers
Data Source
AI summary
Heating treatment is performed on multiple dummy wafers to preheat in-chamber structures including a susceptor and the like prior to the treatment of a semiconductor wafer to be treated. The first few ones of the multiple dummy wafers are heated to a first heating temperature by light irradiation from halogen lamps, and are thereafter irradiated with a flash of light. The subsequent few ones of the multiple dummy wafers are heated to a second heating temperature lower than the first heating temperature by light irradiation from the halogen lamps, and are thereafter irradiated with a flash of light. This stabilizes the temperature of the in-chamber structures in a shorter time with fewer dummy wafers because the dummy wafers are heated to the high temperature and thereafter heated to the low temperature.