Bidirectional Electrostatic Chuck Coolant Flow
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Solution Overview
Problem
Existing electrostatic chuck systems for semiconductor manufacturing face challenges in achieving uniform temperature distribution across wafers due to one-directional coolant flow, leading to uneven cooling and potential damage from non-uniform plasma treatment.
Innovation Solution
An electrostatic chuck assembly with a bidirectional coolant flow system, featuring a channel with openings at the center and edge of the substrate, and a valve box controlling coolant flow direction, allowing coolant to flow either centrifugally towards the edge or centripetally towards the center, ensuring uniform cooling by reversing flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one-directional coolant flow is used in the electrostatic chuck, then the cooling system is simple, but the temperature distribution across the substrate becomes non-uniform
Solution Approach 1:
The patent implements a bidirectional coolant flow system where the flow direction can be dynamically switched between centrifugal (center to edge) and centripetal (edge to center) directions. This dynamic flow reversal enables uniform temperature distribution across the substrate by alternating between different cooling patterns, resolving the contradiction between system simplicity and temperature uniformity.
Solution Approach 2:
The cooling system employs periodic reversal of coolant flow direction through controlled switching between first and second coolant supply channels. This periodic action alternates between centrifugal and centripetal flow patterns, ensuring that different regions of the substrate receive alternating cooling emphasis, thereby achieving overall temperature uniformity without requiring a complex multi-channel permanent system.
2Temperature
If bidirectional coolant flow is implemented, then temperature uniformity across the substrate is improved, but the valve box complexity increases
Solution Approach 1:
The valve box is segmented into distinct functional modules: first and second coolant supply channels with their respective supply valves, first and second return channels with their respective return valves, and a control unit. This segmentation allows independent control of each flow path, simplifying the overall control logic while achieving bidirectional flow capability. Each segment can be activated or deactivated based on the desired flow direction, reducing the complexity burden.
Solution Approach 2:
The valve box structure serves multiple functions: it houses the bidirectional flow control valves, provides thermal management for the electrostatic chuck, and integrates the control unit for automated operation. By consolidating these functions into a single multi-functional component, the patent reduces the need for separate dedicated components, thereby managing overall system complexity while achieving temperature uniformity.
3Temperature
If coolant flow direction is reversed periodically, then uniform cooling is achieved, but the control system complexity increases
Solution Approach 1:
The control unit operates autonomously to manage the bidirectional coolant flow by automatically switching between the first and second coolant supply channels based on predetermined cooling cycles. This self-service control eliminates the need for external manual intervention or complex external control systems, achieving uniform cooling through automated periodic reversal while keeping the control system relatively simple.
Solution Approach 2:
The control unit incorporates feedback mechanisms to monitor the cooling process and adjust the flow direction switching timing accordingly. By using feedback from temperature sensors or process parameters, the system optimizes the reversal frequency and duration to achieve uniform cooling, preventing overheating in specific regions while maintaining simple control logic through rule-based decision making.
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 bidirectional coolant flow system enhances temperature uniformity across the substrate, reducing the risk of damage from uneven cooling and improving the uniformity of plasma treatment processes.
Implementation Method 1
a bidirectional coolant flow system, featuring a channel with openings at the center and edge of the substrate, and a valve box controlling coolant flow direction, allowing coolant to flow either centrifugally towards the edge or centripetally towards the center
Implementation Method 2
the coolant to flow into the channel through the first opening, and the open state of the first return valve may allow the coolant to discharge from the channel through the second opening
Implementation Method 3
Electrostatic chucks may provide uniform heat treatment without producing particles by using an electrostatic force
Data Source
AI summary
An electrostatic chuck assembly, including an electrostatic chuck on which a substrate is loaded; a channel that provides a flow passage for coolant in the electrostatic chuck, the channel having a first opening at a first end corresponding to a center of the substrate and a second opening at a second end corresponding to an edge of the substrate; and a valve box to control a flow direction of the coolant in the channel, the valve box including a first supply valve to control an introduction of the coolant into the first opening; a first return valve to control a drainage of the coolant from the second opening; a second supply valve to control an introduction of the coolant into the second opening; and a second return valve to control a drainage of the coolant from the first opening.