Substrate Support Temperature Control via Multi-Reservoir Fluid Recirculation
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Solution Overview
Problem
Existing plasma processing systems face challenges in rapidly changing substrate temperatures while maintaining stability, which affects throughput and thermal uniformity, particularly due to the large thermal capacitance of fluid reservoirs and the need for compatibility with radio-frequency energy.
Innovation Solution
A recirculation system that uses temperature-controlled liquids to rapidly change substrate temperatures by circulating fluids at different temperatures through a substrate support, eliminating the need for electrical heaters and optimizing heat transfer with a controller managing valve operations to achieve quick temperature adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fluid reservoir is used for temperature control, then the system structure is simple, but the temperature change rate is slow due to large thermal capacitance
Solution Approach 1:
The single fluid reservoir is segmented into multiple separate reservoirs (first fluid reservoir and second fluid reservoir) maintained at different temperatures. This allows the system to switch between temperature sources rapidly without being limited by the thermal capacitance of a single large reservoir, thereby increasing the temperature change rate while keeping the overall system structure relatively simple.
Solution Approach 2:
The multiple fluid reservoirs are pre-cooled or pre-heated to different target temperatures before the temperature change is needed. When a temperature change is required, the system simply switches fluid flow to the reservoir that is already at the desired temperature, eliminating the delay associated with heating or cooling a large thermal mass during the transition.
2Power
If electrical heaters are used for temperature control, then the heating capability is strong, but compatibility issues arise with radio frequency energy requiring custom filtering
Solution Approach 1:
The electrical heating system is replaced with a fluid-based thermal management system. Instead of using electrical heaters that generate heat through resistive heating and require filtering to protect power and control systems from radio frequency interference, the patent uses pre-cooled or pre-heated fluids circulated through the substrate support to achieve temperature control without electrical heating elements in the RF environment.
3Productivity
If substrate temperature is changed rapidly, then the throughput is improved, but temperature stability within a process step deteriorates
Solution Approach 1:
The system dynamically switches between different fluid reservoirs based on the required temperature for the current process step. By having multiple reservoirs at different temperatures and能够快速 switching between them, the system can rapidly change substrate temperature between steps while maintaining stable temperature within each step, as each reservoir provides a consistent temperature source.
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 reduces time constants for temperature changes, enhancing throughput by allowing faster stabilization of substrate temperatures without significant overshooting, thereby improving the efficiency of plasma processing systems.
Implementation Method 1
circulating liquid at a first temperature T1 through a substrate support on which a semiconductor substrate is positioned
Implementation Method 2
A recirculation system which can rapidly change substrate temperature in a plasma processing system by circulating a temperature controlled liquid
Data Source
AI summary
A recirculation system of a substrate support on which a semiconductor substrate is subjected to a multistep process in a vacuum chamber, the system comprising a substrate support having at least one liquid flow passage in a base plate thereof, an inlet and an outlet in fluid communication with the flow passage, a supply line in fluid communication with the inlet, and a return line in fluid communication with the outlet; a first recirculator providing liquid at temperature T1 in fluid communication with the supply line and the return line; a second recirculator providing liquid at temperature T2 in fluid communication with the supply line and the return line, temperature T2 being at least 10° C. above temperature T1; a pre-cooling unit providing liquid at temperature Tpc connected to the inlet and the outlet, temperature Tpc being at least 10° C. below T1; a pre-heating unit providing liquid at temperature Tph connected to the inlet and the outlet, temperature Tph being at least 10° C. above T2; a controller operable to selectively operate valves of the recirculation system to recirculate liquid between the flow passage and the first recirculator, the second recirculator, the pre-cooling unit or the pre-heating unit.