Showerhead Temperature Control via Segmented Cooling and Heating
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Solution Overview
Problem
In high-temperature semiconductor processing, the showerhead faceplate experiences uneven heating due to the narrow gap between the pedestal and the showerhead, leading to a large temperature gradient that can damage the faceplate.
Innovation Solution
A showerhead design featuring a first cooling plate with higher thermal conductivity than the backplate, positioned between the backplate and the faceplate, along with independently controlled heaters around the peripheral region of the faceplate, helps to achieve uniform temperature distribution across the faceplate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the showerhead faceplate is used in high-temperature processing, then the processing temperature is improved, but the temperature gradient across the faceplate increases causing damage
Solution Approach 1:
The showerhead is divided into multiple temperature control zones with independently controllable heaters positioned at different locations (center and periphery). This segmentation allows different regions to be heated independently, reducing temperature gradients across the faceplate while maintaining high processing temperatures.
Solution Approach 2:
Different regions of the showerhead are equipped with specialized temperature control mechanisms. The center region has a cooling plate with heater, while the periphery has separate heaters, creating locally optimized temperature profiles that prevent excessive gradients and damage to the faceplate.
2Reliability
If cooling plate with higher thermal conductivity is used, then temperature uniformity is improved, but device complexity increases
Solution Approach 1:
The showerhead employs a composite structure combining materials with different thermal conductivities. A cooling plate made of high-thermal-conductivity material is positioned at the center, while the backplate uses material with lower thermal conductivity. This composite approach achieves temperature uniformity while managing thermal management complexity.
Solution Approach 2:
A cooling plate acts as an intermediary thermal management component between the heat source and the faceplate. This intermediate element distributes heat more uniformly, reducing temperature gradients without requiring complete redesign of the entire showerhead structure.
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 described configuration effectively reduces temperature gradients across the faceplate, preventing damage and ensuring consistent performance during high-temperature processes.
Implementation Method 1
a first cooling plate arranged between the backplate and a center region of the faceplate... the first cooling plate comprises a material having a higher thermal conductivity than the metallic material of the backplate
Implementation Method 2
a plurality of heaters arranged between the backplate and a peripheral region of the faceplate... each heater of the plurality of heaters is controlled independently
Implementation Method 3
a layer of a thermally resistive material disposed between the plurality of heaters and the backplate. The thermally resistive material has a lower thermal conductivity than the backplate
Data Source
AI summary
A showerhead for a substrate processing system includes a backplate made of a metallic material and a faceplate made of a ceramic material. The showerhead further comprises a first cooling plate arranged between the backplate and a center region of the faceplate and a plurality of heaters arranged between the backplate and a peripheral region of the faceplate.