Temperature Controlled CVD Showerhead for Uniform Film Deposition
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Solution Overview
Problem
Chemical Vapor Deposition (CVD) showerheads experience temperature fluctuations due to variations in process parameters, leading to non-uniform film deposition and reduced operating life, with high temperatures causing particle contamination and film property variations.
Innovation Solution
A temperature-controlled CVD showerhead with enhanced heat transfer features, utilizing a heat conductive stem, back plate, and face plate made of high thermal conductivity materials, coupled with a heating element and heat exchanger, allows for precise temperature control and efficient heat dissipation, maintaining the face plate at lower temperatures despite heat flux from the pedestal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the showerhead is operated at high temperatures to maintain process stability, then the deposition uniformity improves, but the showerhead operating life shortens and particle contamination increases
Solution Approach 1:
The showerhead is divided into distinct functional zones with different temperature control capabilities. The face plate is separated from the stem and back plate, allowing independent temperature management of the gas distribution surface versus the structural support elements.
Solution Approach 2:
The patent implements active temperature control by changing the thermal parameters of the showerhead through heating elements and cooling mechanisms. This allows the showerhead to operate at optimized temperatures that balance deposition uniformity with component longevity, rather than relying on passive high-temperature operation.
2Manufacturing precision
If the showerhead temperature is increased to stabilize the deposition process, then the film quality improves, but aluminum fluoride formation and particle contamination increase
Solution Approach 1:
The patent actively controls and optimizes the temperature parameter of the showerhead face plate to maintain film quality while avoiding the threshold temperatures that cause aluminum fluoride formation. This prevents the harmful chemical reactions that lead to particle contamination.
Solution Approach 2:
The temperature control system uses feedback from temperature sensors to adjust heating and cooling mechanisms, maintaining the showerhead face plate at precise temperature levels that prevent contaminant formation while ensuring stable deposition.
3Productivity
If the showerhead is heated by radiation from the substrate and plasma to maintain process temperature, then the deposition continues, but temperature fluctuations increase and uniformity deteriorates
Solution Approach 1:
The showerhead structure separates the face plate (exposed to plasma and substrate radiation) from the thermally massive stem and back plate. This segmentation allows the face plate to respond to process conditions while the bulk structure provides thermal stability, reducing temperature fluctuations.
Solution Approach 2:
The patent implements active temperature control mechanisms that counteract the heating effects of plasma and substrate radiation. Heating elements and cooling systems adjust thermal parameters in real-time to maintain uniform temperature despite continuous deposition processes.
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 solution achieves stable and uniform film deposition, extends the showerhead's operating life, reduces particle contamination, and improves substrate-to-substrate uniformity by maintaining the face plate temperature between 100° C and 300° C, while the substrate support operates at higher temperatures.
Implementation Method 1
A temperature controlled CVD showerhead with enhanced heat transfer features, using a heat conductive stem, back plate, and face plate made of high thermal conductivity materials
Implementation Method 2
coupled with a heating element and heat exchanger, allows for precise temperature control and efficient heat dissipation, maintaining the face plate at lower temperatures despite heat flux from the pedestal
Implementation Method 3
coupled with a heating element and heat exchanger, allows for precise temperature control and efficient heat dissipation
Implementation Method 4
In certain embodiments, heat dissipation is also a result of providing high emissivity external surfaces on the back plate and the stem
Data Source
AI summary
A temperature controlled showerhead assembly for chemical vapor deposition (CVD) chambers enhances heat dissipation to provide accurate temperature control of the showerhead face plate and maintain temperatures substantially lower than surrounding components. Heat dissipates by conduction through a showerhead stem and removed by the heat exchanger mounted outside of the vacuum environment. Heat is supplied by a heating element inserted into the steam of the showerhead. Temperature is controlled using feedback supplied by a temperature sensor installed in the stem and in thermal contact with the face plate.