High-Temperature Showerhead Structure to Prevent Aluminum Creep
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Solution Overview
Problem
Conventional semiconductor processing chamber showerheads made from aluminum alloys lose strength and deform when exposed to high temperatures, limiting their suitability for high-temperature processing operations and resulting in residue buildup and defects on wafers.
Innovation Solution
The development of showerheads with an inner core region made from a high-thermal-conductivity aluminum alloy, an outer core region with a lower thermal conductivity annular liner, and an intermediate material to manage thermal expansion, combined with rapid cooling techniques to form solid aluminum alloy particles, which are then compacted and coated to enhance strength and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional aluminum alloy showerheads are used, then they provide good thermal conductivity and electrical properties, but they lose strength and deform at high temperatures
Solution Approach 1:
The showerhead is divided into multiple regions with different materials: an inner core region made from high-thermal-conductivity aluminum alloy for thermal and electrical performance, and an outer core region with an annular liner made from high-temperature-strength material to provide structural integrity at elevated temperatures. This segmentation allows each region to optimize for its specific function.
Solution Approach 2:
The showerhead employs a composite structure combining aluminum alloy (for thermal conductivity and electrical properties) with high-temperature-strength material (for structural stability). This composite approach enables the showerhead to simultaneously achieve good thermal conductivity, electrical properties, and resistance to high-temperature deformation.
2Reliability
If aluminum alloy showerheads are used at high temperatures, then they provide good electrical conductivity, but they experience creep and deformation
Solution Approach 1:
The showerhead is segmented into an inner core region containing the aluminum alloy for electrical conductivity and an outer core region with high-temperature-strength material for structural stability. This segmentation isolates the aluminum alloy from direct high-temperature exposure while maintaining its electrical function.
Solution Approach 2:
Different regions of the showerhead are assigned different material properties: the inner core region uses aluminum alloy optimized for electrical conductivity and thermal management, while the outer core region uses material optimized for high-temperature structural stability. Each region's material is locally optimized for its specific functional requirements.
3Strength
If rapid cooling is used to form solid aluminum alloy particles, then they achieve fine microstructure and high strength, but the manufacturing process becomes more complex
Solution Approach 1:
The manufacturing process utilizes extreme parameter changes, specifically rapid cooling rates (at least 10³ K/sec) during solidification of the aluminum alloy. This rapid cooling transforms the microstructure to achieve fine-grained, high-strength material properties. The process complexity is managed through specialized equipment capable of controlled rapid solidification.
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 solution enables showerheads to withstand higher processing temperatures without deformation or creep, reducing residue buildup and defects, and allowing for quicker cleaning and higher deposition rates.
Implementation Method 1
cooling the melted aluminum alloy composition at a rate of at least 10³ K/sec to form solid aluminum alloy particles
Implementation Method 2
The annular liner may have a lower thermal conductivity than the aluminum alloy
Implementation Method 3
The intermediate material may have a coefficient of thermal expansion that is between a coefficient of thermal expansion of the aluminum alloy and a coefficient of thermal expansion of the annular liner
Implementation Method 4
coating the showerhead with one of aluminum or aluminum oxide. Coating the showerhead may include electroplating aluminum onto the showerhead
Implementation Method 5
Coating the showerhead may include applying aluminum oxide onto the showerhead via atomic layer deposition
Data Source
AI summary
Methods of manufacturing a semiconductor processing chamber showerheads may include forming a melted aluminum alloy composition, cooling the melted aluminum alloy composition at a rate of at least 103 K/sec to form solid aluminum alloy particles, and forming a core region of a showerhead from the solid aluminum alloy particles. The core region of the showerhead may include an inner core region and an outer core region that may be coupled together. The inner core region may define a plurality of apertures. The outer core region may define a channel that receives a heating element. The methods may include coating the core region with one of aluminum or aluminum oxide and joining a peripheral edge of the outer core region with an inner edge of a metallic annular liner. The metallic annular liner may have a lower thermal conductivity than the core region of the showerhead.