Rotating Susceptor Thermal Equalization Using Pulsed Control Gas
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Solution Overview
Problem
Existing thermal treatment devices face challenges in achieving a homogeneous temperature profile on the susceptor due to non-uniform electrical conductivity, leading to local temperature differences that affect substrate processing quality.
Innovation Solution
The implementation of a system that periodically alters heat supply or removal to the susceptor through synchronized thermal influence zones, using gases with varying thermal conductivities to compensate for local conductivity variations, synchronized with the susceptor's rotation, and adjusting the thermal conductivity of the medium between the susceptor and a temperature control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pulsed laser beam is used to supply locally limited heat to a rotating susceptor, then heat can be applied with high precision and control, but the system complexity increases and the process becomes more difficult to scale
Solution Approach 1:
The patent replaces complex mechanical positioning systems with a rotating susceptor approach. Instead of moving heat application components precisely, the susceptor rotates to bring different zones past fixed heating regions, simplifying the overall system while maintaining heat application precision through rotational synchronization.
Solution Approach 2:
The patent employs periodic pulsed heating synchronized with the susceptor rotation. Heating elements are activated in periodic pulses that correspond to the rotational period, creating controlled thermal zones that move with the rotation. This periodic action allows precise heat application without requiring complex continuous positioning mechanisms.
2Ease of manufacture
If the susceptor material has non-uniform electrical conductivity, then manufacturing is simpler and more cost-effective, but local temperature differences arise that degrade processing quality
Solution Approach 1:
The patent applies local quality by providing different thermal influence zones at different radial positions of the susceptor. The heating and cooling are selectively applied to specific zones rather than uniformly across the entire susceptor surface. This allows compensation for local conductivity variations by tailoring the thermal treatment to each specific zone's characteristics.
Solution Approach 2:
The patent changes thermal parameters (heating/cooling rates, pulse duration, gas flow rates) dynamically based on the susceptor's rotational position and the local thermal conditions. By adjusting these parameters in real-time during rotation, the system compensates for non-uniform conductivity while maintaining overall temperature uniformity across the susceptor surface.
3Device complexity
If thermal influence zones are fixed in location with respect to the housing, then the control system is simplified, but the heat distribution becomes less adaptable to varying susceptor conditions
Solution Approach 1:
The patent creates a dynamic system where fixed thermal influence zones in the housing are synchronized with the rotating susceptor. Although the zones are fixed relative to the housing, their effect on the susceptor is dynamic due to rotation. The control system adjusts heating/cooling pulse timing based on rotational position, making the fixed zones effectively adaptive to varying susceptor conditions without increasing structural complexity.
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 compensates for local temperature differences on the susceptor, ensuring a more uniform temperature profile and improved substrate processing quality by targeted heat management.
Implementation Method 1
The induction coil generates a high-frequency alternating field, which generates eddy currents within the susceptor, so that the susceptor can heat up to a process temperature
Implementation Method 2
The induction coil generates a high-frequency alternating field, which generates eddy currents within the susceptor
Implementation Method 3
a gas mixture of a highly thermally conductive gas and a poorly thermally conductive gas can be fed into a gap between a heater and the lower face of a susceptor
Implementation Method 4
The temperature of the lower face of the susceptor is measured by a first pyrometer. The temperature of the substrates lying on the substrate holder is measured by a second pyrometer
Data Source
AI summary
In the thermal treatment of substrates, a susceptor is used to hold at least one substrate. The susceptor can be heated with a heater and driven in rotation about a rotation axis by a rotary drive. Means are provided to influence the heat transfer to or from the susceptor in a locally limited manner, synchronized with the rotary movement of the susceptor, to equalize local temperature differences on the rotating susceptor. In particular, a temperature control gas with changing heat conduction properties is periodically fed in a pulsed manner through a feed opening into a gap between the susceptor and a cooling unit.