Semiconductor Wafer Temperature Control Using Temporary Tank 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 a cold tank, along with 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 surge volumes of thermal transfer fluid to temporary tanks for temperature equilibration before returning them to the main tanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
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 handle different thermal loads in different time periods, preventing any single chiller from being overwhelmed by excessive thermal load during large temperature transitions.
Solution Approach 2:
The system pre-cools or pre-heats thermal transfer fluid in separate tanks before it contacts the substrate holder. By preparing the thermal transfer fluid in advance in dedicated tanks, the system can rapidly switch between temperature states without overloading the chillers during the actual temperature transition.
2Device complexity
If a single chiller is used to control temperature during large temperature changes, then the system complexity is reduced, but the temperature control precision deteriorates
Solution Approach 1:
The thermal management system divides the single chiller function into multiple independent chillers, each responsible for a specific tank. This segmentation allows each chiller to operate within optimal thermal load ranges, maintaining temperature control precision while distributing system complexity across multiple manageable units.
Solution Approach 2:
Thermal transfer fluid acts as an intermediary between the chillers and the substrate holder. The fluid is pre-cooled or pre-heated in separate tanks before contacting the substrate holder, allowing temperature transitions without directly overloading the chillers, thus maintaining precision.
3Speed
If thermal transfer fluid is directly circulated between the chiller and substrate holder during temperature switching, then the response time is reduced, but temperature deviation in the tanks increases
Solution Approach 1:
The system performs preliminary cooling or heating of thermal transfer fluid in dedicated tanks before the fluid contacts the substrate holder. This pre-conditioning maintains temperature stability in the tanks while enabling rapid temperature response when the fluid is circulated to the substrate holder.
Solution Approach 2:
The thermal transfer fluid serves as an intermediary that can be independently conditioned in separate tanks. By decoupling the tank temperature stability from the substrate holder temperature response speed, the system achieves both goals through the mediator fluid that can be prepared in advance and then rapidly deployed.
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 tanks and improving processing efficiency by minimizing thermal load imbalances and maintaining desired temperatures within short time frames.
Implementation Method 1
A heating and cooling apparatus with a hot tank and a cold tank, along with a temporary storage tank, is used to manage thermal transfer fluids
Implementation Method 2
directing surge volumes of thermal transfer fluid to temporary tanks for temperature equilibration before returning them to the main tanks
Implementation Method 3
directing surge volumes of thermal transfer fluid to temporary tanks for temperature equilibration before returning them to the main tanks
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.