Vacuum Anneal Reflector Control for Wafer Temperature Uniformity
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Solution Overview
Problem
In semiconductor processing, maintaining temperature uniformity of a workpiece during thermal processing is challenging, especially in vacuum environments where rotation is difficult, and traditional stationary sensors struggle to obtain accurate temperature profiles without rotating the workpiece.
Innovation Solution
A workpiece processing apparatus with controllable reflectors that adjust the position of radiation to compensate for the lack of rotation, using a control system that directs radiation in a grid-like pattern and adjusts based on temperature profiles to ensure uniform heating, allowing for temperature uniformity maintenance without rotating the workpiece, even in vacuum conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the workpiece is rotated to achieve uniform temperature distribution, then temperature uniformity is improved, but device complexity increases and operation becomes more difficult in vacuum environments
Solution Approach 1:
Instead of rotating the workpiece to achieve uniform heating, the patent inverts the approach by keeping the workpiece stationary and rotating the radiation sources and reflectors. This maintains the relative motion needed for uniform temperature distribution while avoiding the complexity of rotating the workpiece itself in the vacuum chamber.
Solution Approach 2:
The patent replaces the mechanical rotation of the workpiece with a controlled radiation distribution system using movable radiation sources and reflectors. This substitution eliminates the need for mechanical rotation mechanisms on the workpiece while achieving the same thermal uniformity through optical/thermal field control.
2Device complexity
If stationary sensors are used to measure temperature, then device complexity is reduced, but measurement precision deteriorates because accurate temperature profiles cannot be obtained without rotating the workpiece
Solution Approach 1:
The patent introduces movable radiation sources and reflectors as intermediaries between the stationary sensors and the workpiece. These intermediaries enable the system to obtain comprehensive temperature profile data by moving the radiation elements relative to the stationary sensors, maintaining measurement precision without requiring workpiece rotation.
Solution Approach 2:
The system creates multiple virtual measurement points by moving the radiation sources and reflectors around the stationary workpiece. This allows stationary sensors to effectively capture temperature information from multiple locations on the workpiece surface without the sensors or workpiece needing to rotate.
3Temperature
If the workpiece is rotated to apply radiation uniformly, then temperature uniformity is improved, but ease of operation deteriorates in vacuum conditions where rotation is difficult
Solution Approach 1:
The patent inverts the traditional approach by keeping the workpiece stationary and rotating the radiation delivery system instead. This inversion makes operation easier in vacuum conditions since the radiation sources and reflectors can be rotated outside or at the boundary of the vacuum chamber, avoiding the difficulties of rotating components within the vacuum environment.
4Manufacturing precision
If radiation sources are moved to control temperature distribution, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the radiation control system into separate functional modules: radiation sources, movable reflectors, and positioning mechanisms. This segmentation allows each component to be optimized independently and simplifies the overall control system, achieving precise temperature distribution control without excessive complexity.
Solution Approach 2:
The system uses dynamic positioning of radiation sources and reflectors to adaptively control temperature distribution across the workpiece surface. This dynamic approach allows real-time adjustment of radiation patterns based on measured temperature profiles, achieving high manufacturing precision through flexible, programmable control rather than complex fixed mechanisms.
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 solution improves thermal uniformity, reducing defects and non-uniformities by simulating rotation and enabling precise temperature control within the processing chamber, even when rotation is not feasible, thereby enhancing the quality of semiconductor wafers.
Implementation Method 1
one or more radiative heating sources configured to emit radiation onto a back side of the workpiece
Implementation Method 2
a plurality of reflectors configured to direct radiation emitted from the radiative heating sources toward the workpiece
Data Source
AI summary
A workpiece processing apparatus is provided. The workpiece processing apparatus can include a processing chamber and a workpiece disposed on a workpiece support within the processing chamber. The workpiece processing apparatus can include a gas delivery system and one or more exhaust ports for removing gas from the processing chamber such that a vacuum pressure can be maintained. The workpiece processing apparatus can include radiative heating sources configured to heat the workpiece. The workpiece processing apparatus can further include a plurality of reflectors. The workpiece processing apparatus can include a control system configured to control one or more positions of the reflectors.