Microwave Window Coolant Channel for Plasma Reactor Thermal Management
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Solution Overview
Problem
Microwave-based semiconductor wafer processing faces challenges in achieving uniform plasma distribution and high power delivery without damaging the microwave window, leading to non-uniform deposition rates and prolonged processing times.
Innovation Solution
A reactor design that includes a rotatable microwave antenna and a coolant channel through the microwave window to maintain uniform power distribution and high power levels, utilizing a microwave radiator with a cylindrical housing and a coolant circulator to manage heat and prevent window damage, along with a combination of microwave and inductively coupled RF power for controlled ion energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high microwave power is delivered to the chamber, then processing speed and plasma density are improved, but the microwave window is damaged
Solution Approach 1:
A coolant channel is introduced as an intermediary component between the microwave window and the chamber interior. This channel allows coolant to flow through and absorb heat from the window, acting as a thermal mediator that protects the window from direct thermal damage while enabling high microwave power operation
Solution Approach 2:
A liquid coolant system is implemented using hydraulic principles. The coolant flows through the coolant channel in the microwave window, absorbing thermal energy through convection and conduction, then is circulated back through a cooling system. This hydraulic cooling mechanism enables the window to withstand high microwave power levels that would otherwise cause damage
2Productivity
If microwave power is used to generate high plasma density, then deposition time is reduced, but uniformity of power distribution deteriorates
Solution Approach 1:
The microwave antenna is made rotatable rather than fixed, transforming it from a static to a dynamic component. By rotating the antenna during the deposition process, the periodic power deposition pattern is averaged out over time, resulting in uniform plasma distribution and uniform deposition rates across the substrate while maintaining high overall deposition speed
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 design achieves uniform plasma distribution and significantly reduces processing time by allowing high microwave power delivery, enabling efficient DLC film deposition with minimal lattice defects and improved material quality.
Implementation Method 1
a coolant channel extending along a radial plane through the microwave transmissive window
Implementation Method 2
a coolant circulator coupled to the coolant channel
Implementation Method 3
a microwave radiator overlying the microwave transmissive window
Implementation Method 4
The power may be employed, for example, to generate a plasma
Data Source
AI summary
A plasma reactor has a microwave source including a microwave window with a channel extending through the window and a coolant source for flowing a coolant through the channel. The coolant is a liquid that does not absorb microwave power.