Plasma Processing Apparatus Reflector for Wafer Heating Efficiency
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Solution Overview
Problem
Conventional plasma processing technologies require both heating and cooling functions, leading to inefficiencies in wafer heating due to the need for separate cooling and heating methods, which can result in uneven temperature distribution and reduced heating capability when using Inductivity Coupled Plasma (ICP) sources with quartz vessels, as light radiation is compromised by power loss through the sidewall.
Innovation Solution
A plasma processing apparatus with a dielectric material sidewall and an ICP coil outside the quartz chamber, where an IR lamp is positioned above the coil and a reflector is used to redirect leaked IR light back into the chamber, enhancing wafer heating efficiency while maintaining a strong electric field for plasma formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a quartz vessel is used with ICP source, then plasma formation is maintained, but light radiation for heating is compromised due to power loss through the sidewall
Solution Approach 1:
A reflective layer is introduced as an intermediary between the quartz vessel sidewall and the external environment. This reflective layer intercepts light radiation that would otherwise be lost through the quartz sidewall and redirects it back into the processing chamber, thereby recovering energy that would have been wasted and improving wafer heating efficiency without compromising plasma formation
Solution Approach 2:
The transparent nature of the quartz vessel, which causes light loss through the sidewall, is converted into a benefit by adding a reflective layer. The reflective layer transforms the harmful light loss into useful heating by reflecting the light back into the chamber, turning the transparency disadvantage into a heating advantage
2Temperature
If separate cooling and heating functions are implemented, then wafer temperature control is achieved, but device complexity and heating uniformity are reduced
Solution Approach 1:
The ICP source is designed to serve multiple functions: it generates plasma for processing and simultaneously provides heating through light radiation. By making the plasma source multi-functional, the need for a separate heating system is reduced, simplifying the overall device structure while maintaining temperature control capability when combined with the cooling function
3Power
If ICP source is used with quartz vessel, then plasma is formed effectively, but heating capability becomes uneven due to light radiation loss
Solution Approach 1:
The reflective layer acts as a mediator that redistributes the light radiation within the processing chamber. By reflecting light that would escape through the quartz sidewall back into the chamber, it creates a more uniform radiation distribution pattern, thereby improving temperature distribution uniformity while preserving the strong plasma electric field
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 configuration minimizes temperature unevenness and improves wafer processing efficiency by effectively radiating light for heating while maintaining a robust plasma electric field, allowing for precise control of etching processes.
Implementation Method 1
a coil disposed on an outer side of the sidewall therearound, the coil being supplied with radio-frequency power for forming plasma above the stage in the processing chamber
Implementation Method 2
a lamp disposed above the coil outside the vacuum vessel, the lamp radiating light onto the wafer from an upper portion of the processing chamber
Implementation Method 3
a reflector disposed on an outer side of the coil therearound, the reflector reflecting light to irradiate an inside of the processing chamber
Data Source
AI summary
A plasma processing apparatus includes a processing chamber to be depressurized in a vacuum vessel with a sidewall made of a transparent or translucent dielectric material, a stage in the processing chamber to mount a wafer thereon, a coil disposed around an outer side of the sidewall and supplied with radio-frequency power for forming plasma above the stage in the processing chamber, a lamp disposed above the coil outside the vacuum vessel which radiates light onto the wafer, and a reflector disposed the coil and reflecting light to irradiate an inside of the processing chamber.