Segmented Heat Transfer Plate for Plasma Showerhead Temperature Uniformity
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Solution Overview
Problem
In semiconductor substrate fabrication, temperature variations during plasma processing lead to inconsistent substrate surface characteristics and reduced die yield due to the proportional influence of substrate temperature on plasma reactivity, necessitating improved temperature control methods.
Innovation Solution
A heat transfer plate with independently controllable gas volumes is integrated into the showerhead electrode assembly of a capacitively coupled plasma processing apparatus, allowing for precise control of temperature distribution across the plasma-exposed surface by adjusting gas pressures within these volumes, thereby compensating for thermal gradients and ensuring uniform etching results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional showerhead electrode assembly is used, then the structure is simple, but temperature uniformity across the plasma-exposed surface deteriorates
Solution Approach 1:
The heat transfer plate is divided into multiple independently controllable gas volumes (e.g., first, second, third gas volumes) that are fluidly isolated from each other. Each gas volume can have its pressure independently adjusted to control heat transfer to different regions of the showerhead electrode assembly, enabling localized temperature control and compensating for thermal gradients across the plasma-exposed surface.
Solution Approach 2:
Different regions of the showerhead electrode assembly are provided with different gas pressures in the segmented gas volumes to achieve locally optimized heat transfer. This allows each region to have tailored thermal characteristics, with higher gas pressure in regions requiring more heat transfer and lower pressure in regions requiring less heat transfer, thereby achieving overall temperature uniformity.
2Temperature
If gas pressure is increased to improve heat transfer, then temperature control improves, but gas pressure variations affect the entire electrode assembly uniformly
Solution Approach 1:
The heat transfer plate is segmented into multiple fluidly isolated gas volumes, each capable of independent pressure control. This segmentation enables each region of the electrode assembly to have its gas pressure independently adjusted, providing adaptability to control temperature in different regions without affecting other regions.
Solution Approach 2:
The gas pressures in the segmented volumes are made dynamically adjustable and independently controllable, allowing the system to adapt to different thermal requirements in different regions. This dynamic control enables real-time optimization of temperature distribution across the plasma-exposed surface.
3Manufacturing precision
If substrate temperature is not controlled, then process simplicity is maintained, but substrate surface characteristics deteriorate
Solution Approach 1:
Temperature sensors are positioned to detect temperatures at different locations on the showerhead electrode assembly, and this temperature information is fed back to a control system. The control system uses this feedback to independently adjust the gas pressures in the segmented volumes, creating a closed-loop control system that maintains substrate surface characteristics within desired specifications.
Solution Approach 2:
The system controls substrate surface characteristics by changing the gas pressure parameter in the segmented heat transfer plate. By adjusting gas pressure, the thermal conductivity of the gas is modified, which directly affects heat transfer to the substrate and thereby controls substrate temperature and resulting surface characteristics.
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 enables more uniform temperature control across the plasma-exposed surface of the showerhead electrode, enhancing the consistency of semiconductor substrate processing and improving die yield by minimizing temperature-related variations.
Implementation Method 1
the heat transfer plate comprises a plurality of independently controllable gas volumes defined to be fluidly isolated from others of the plurality of independently controllable gas volumes
Implementation Method 2
exposing a substrate to a plasma to allow the reactive constituents of the plasma to modify the surface of the substrate, e.g., remove material from unprotected areas of the substrate surface
Data Source
AI summary
A heat transfer plate useful in a showerhead electrode assembly of a capacitively coupled plasma processing apparatus. The heat transfer plate includes independently controllable gas volumes which may be pressurized to locally control thermal conductance between a heater member and a cooling member such that uniform temperatures may be established on a plasma exposed surface of the showerhead electrode assembly.