Wafer Placement Table Cooling Path for Uniform Wafer Temperature
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Solution Overview
Problem
Existing wafer placement tables with refrigerant flow paths that gradually decrease in cross-sectional area from the inlet to the outlet fail to sufficiently improve temperature uniformity of wafers.
Innovation Solution
A wafer placement table design featuring a refrigerant flow path with variable sections that adjust cross-sectional area and velocity to minimize differences in heat extraction performance, including first and second variable sections with expanding and contracting areas to maintain uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cross-sectional area of the refrigerant flow path gradually decreases from inlet to outlet, then the refrigerant velocity increases and heat exchange efficiency improves, but the temperature uniformity of the wafer is not sufficiently improved
Solution Approach 1:
The refrigerant flow path is divided into multiple sections (first variable section, first expansion section, second variable section, second expansion section) with different cross-sectional area characteristics. Each section performs a specific function: variable sections increase velocity and heat exchange efficiency, while expansion sections reduce pressure loss and prevent excessive velocity increase. This segmentation allows the system to achieve better temperature uniformity without excessive complexity.
Solution Approach 2:
Different sections of the flow path are given different local characteristics. The variable sections have decreasing cross-sectional area to increase velocity where heat exchange is needed, while expansion sections have increasing cross-sectional area to reduce pressure loss. This local differentiation optimizes heat extraction performance at different locations, improving overall temperature uniformity.
2Use of energy by moving object
If the cross-sectional area of the refrigerant flow path is continuously decreased to increase velocity, then heat exchange efficiency improves, but pressure loss increases excessively
Solution Approach 1:
The flow path alternates between variable sections (for heat exchange) and expansion sections (for pressure recovery). This segmentation allows the system to periodically reduce pressure loss while maintaining heat exchange efficiency, preventing excessive cumulative pressure loss.
Solution Approach 2:
Expansion sections are positioned before variable sections to preemptively reduce pressure loss before the refrigerant enters the next velocity-increasing section. This preliminary action prevents excessive pressure loss from accumulating, ensuring sufficient refrigerant pressure reaches each heat exchange zone.
3Speed
If the refrigerant velocity increases throughout the flow path, then heat extraction performance improves, but temperature distribution becomes non-uniform
Solution Approach 1:
The flow path is segmented into velocity-increasing variable sections and pressure-recovery expansion sections. This creates a rhythmic pattern of velocity changes that prevents continuous high velocity, allowing more uniform heat extraction across different radial positions and improving temperature distribution uniformity.
Solution Approach 2:
The cross-sectional area parameter is dynamically changed along the flow path through alternating expansion and contraction sections. This parameter modulation creates optimal velocity profiles at different locations, ensuring uniform heat extraction and temperature distribution across the wafer surface.
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 design achieves significantly improved temperature uniformity of wafers by reducing differences in heat extraction performance across the flow path, resulting in a more uniform temperature distribution.
Implementation Method 1
a cooling plate disposed on a lower surface of the ceramic plate; and a refrigerant flow path extending in the cooling plate
Implementation Method 2
The temperature of the refrigerant increases from the inlet to the outlet of the refrigerant flow path, and the velocity of the refrigerant increases from the inlet to the outlet of the refrigerant flow path
Data Source
AI summary
A wafer placement table includes a ceramic plate, a cooling plate and a refrigerant flow path. The refrigerant flow path has a first variable section and a second variable section. The first variable section is provided such that the cross-sectional area of the refrigerant flow path gradually decreases as it proceeds in the direction of refrigerant flow from a starting point of the first variable section. The second variable section is provided such that, after the cross-sectional area of the refrigerant flow path is once expanded from the cross-sectional area of the refrigerant flow path at an end point of the first variable section in a first expansion section right before a starting point of the second variable section, the cross-sectional area of the refrigerant flow path gradually decreases as it proceeds in the direction of refrigerant flow from the starting point of the second variable section.