Semiconductor Wafer Thermal Control with Temporary Fluid Buffering
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Solution Overview
Problem
Existing semiconductor device processing tools face challenges in maintaining desired temperature tolerances and time frames, especially when large temperature changes are required, leading to thermal load imbalances and inefficient temperature control.
Innovation Solution
A heating and cooling apparatus with a hot tank and cold tank system, including a temporary storage tank, is used to manage thermal transfer fluids, allowing for rapid and precise temperature changes of up to 300°C without excessive heating or cooling times by directing thermal transfer fluid surges to a temporary tank for temperature equalization before returning it to the main tanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the temperature of the etch tool is changed by a temperature greater than about 50°C, then the cleaning effectiveness is improved, but the thermal load on the chiller becomes too large to adequately control the temperature within a desired time
Solution Approach 1:
The thermal management system is segmented into multiple independent tanks (first tank, second tank, third tank) that can be selectively activated. This allows the system to divide the thermal load management into separate stages, preventing any single chiller from being overwhelmed by excessive thermal loads while enabling effective temperature transitions for cleaning.
Solution Approach 2:
A third tank is introduced as an intermediary thermal management component between the process chamber and the chillers. This third tank absorbs or provides thermal energy during temperature transitions, acting as a buffer that reduces the immediate thermal load on the chillers while enabling rapid temperature changes for effective cleaning.
2Device complexity
If a single chiller is used to control temperature, then the system complexity is reduced, but the system cannot adequately handle large temperature changes within desired time frames
Solution Approach 1:
The thermal management system is divided into multiple tanks (first, second, and third tanks) that can be independently controlled. This segmentation allows parallel thermal management operations, enabling rapid temperature transitions without requiring an overly complex single-system solution, thus maintaining manageable complexity while improving productivity.
Solution Approach 2:
The system pre-cools or pre-heats thermal transfer fluid in the third tank before it is needed for temperature transitions. This preliminary action prepares the thermal management system in advance, enabling rapid temperature changes in the process chamber without waiting for thermal equilibrium, thus improving temperature transition speed while keeping the system design straightforward.
3Speed
If thermal transfer fluid is rapidly circulated to change temperature, then the temperature control speed is improved, but thermal load imbalances occur in the tanks
Solution Approach 1:
The third tank serves as a thermal intermediary that balances loads between the first and second tanks. When rapid temperature changes are needed, the third tank can absorb excess thermal energy or provide pre-conditioned fluid, preventing thermal load imbalances in the main tanks while maintaining fast temperature control speed through coordinated operation of all three tanks.
Solution Approach 2:
The system dynamically changes operational parameters by selectively activating different tank combinations based on the required temperature transition. This allows the system to optimize between speed and thermal load balance by adjusting which tanks are active and how thermal transfer fluid is circulated, maintaining stability while achieving rapid temperature changes when needed.
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 enables rapid and precise temperature control of semiconductor wafers, reducing temperature deviation in the hot and cold tanks and improving processing efficiency by maintaining desired temperatures within short time frames, even during extreme temperature changes.
Implementation Method 1
A heating and cooling apparatus with a hot tank and cold tank system, including a temporary storage tank, is used to manage thermal transfer fluids
Implementation Method 2
directing thermal transfer fluid surges to a temporary tank for temperature equalization before returning it to the main tanks
Implementation Method 3
The platform may comprise an electrostatic chuck configured to thermally couple a semiconductor wafer to the platform
Data Source
AI summary
A system for fabricating a semiconductor device structure includes a tool comprising a chamber and a platform within the chamber configured to receive a semiconductor device structure thereon. The tool further includes a heating and cooling system in operable communication with the platform and configured to control a temperature of the platform. The heating and cooling system comprises a cooling system including a cold tank for containing a cold thermal transfer fluid, the cold tank configured to be in fluid communication with the platform, thermal transfer fluid supply piping, and thermal transfer fluid return piping, a heating system including a hot tank for containing a hot thermal transfer fluid having a higher temperature than the cold thermal transfer fluid, the hot tank configured to be in fluid communication with the platform, the thermal transfer fluid supply piping, and the thermal transfer fluid return piping, and at least one temporary storage tank configured to receive at least some of the cold thermal transfer fluid or the hot thermal transfer fluid from at least the thermal transfer fluid return piping after switching a thermal load from the platform from one of the cooling system or the heating system to the other of the cooling system or the heating system. Related methods and tools are disclosed.