Rotatable RTP Chamber Assembly for Uniform Substrate Heating
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Solution Overview
Problem
Thermal processing chambers often heat substrates unevenly due to strong background radiation, leading to inefficient annealing processes in semiconductor processing.
Innovation Solution
A rotatable assembly within the thermal processing chamber, featuring a pedestal shaft, pedestal plate, and magnetic fluid seal, allows for the rotation of substrates during annealing, ensuring even heating and maintaining a vacuum environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a substrate is heated in a thermal processing chamber using radiation from thermal sources, then the substrate temperature is raised for annealing, but the radiation creates a strong background radiation environment that causes uneven heating of the substrate
Solution Approach 1:
The substrate is rotated during thermal processing using a rotatable assembly with a pedestal shaft and pedestal plate. This dynamic movement allows the substrate to continuously change its position relative to the thermal sources, ensuring that all areas receive relatively uniform radiation exposure over time, thereby achieving even heating throughout the annealing process
Solution Approach 2:
The rotation of the substrate follows a periodic cyclic motion, where the substrate completes full rotations at controlled speeds. This periodic action ensures that each point on the substrate surface periodically passes through different positions relative to the thermal sources, distributing the radiation exposure uniformly and eliminating hot spots or uneven heating zones
2Manufacturing precision
If a rotatable assembly is introduced to rotate the substrate during annealing, then even heating is achieved, but the complexity of the chamber increases with additional components like pedestal shaft, pedestal plate, and magnetic fluid seal
Solution Approach 1:
The magnetic fluid seal is positioned at the boundary between the rotating and stationary portions of the chamber, extracting the sealing function from the main chamber structure. This allows the rotatable assembly to be implemented with minimal impact on the overall chamber design, as the seal is localized to a specific interface rather than requiring complex sealing mechanisms throughout the chamber
Solution Approach 2:
The pedestal shaft serves multiple functions: it provides the mechanical axis for rotation, supports the substrate through the pedestal plate, and acts as a barrier for the magnetic fluid seal. By consolidating these functions into a single component, the overall device complexity is reduced despite adding rotation capability to achieve uniform heating
3Reliability
If a magnetic fluid seal is used to maintain vacuum while allowing rotation, then vacuum integrity is preserved with minimal maintenance, but the seal complexity increases compared to traditional mechanical seals
Solution Approach 1:
The magnetic fluid seal replaces traditional mechanical contact seals (such as sliding seals or labyrinth seals) with a magnetic field-based sealing mechanism. The magnetic fluid forms a seal through magnetic attraction forces without mechanical contact, eliminating wear and friction issues associated with mechanical seals. This substitution maintains vacuum integrity while reducing maintenance requirements, despite the specialized nature of the magnetic fluid system
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
The solution enables even heating of substrates with minimal maintenance and reduced particle generation, improving the reliability and efficiency of the annealing process.
Implementation Method 1
The chamber includes a magnetic fluid seal disposed between the pedestal shaft and the pedestal housing. The magnetic fluid seal is configured to maintain a vacuum inside the thermal processing chamber.
Implementation Method 2
Thermal processing chambers commonly expose a substrate to radiation from thermal sources to raise the temperature of the substrate
Data Source
AI summary
The present disclosure relates to heating a substrate in a rapid thermal processing (RTP) chamber. The chamber may contain a rotatable assembly configured to accommodate and rotate the substrate while a heat source inside the RTP chamber applies heat to the substrate. The rotatable assembly is partially disposed outside the RTP chamber. A seal may formed around the rotatable assembly and maintain a vacuum inside the RTP chamber while the rotatable assembly rotates. The rotatable assembly may configured to accommodate various-sized substrates.