Rotating Showerhead Flow Ring for ALD Gas Purge Control
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Solution Overview
Problem
Existing showerhead assemblies in semiconductor processing systems face challenges in achieving effective purge of the reaction chamber within a desired time period due to limited exhaust paths, which can lead to incomplete saturation/reactions and reduced efficiency during processes like atomic layer deposition.
Innovation Solution
The implementation of an annular flow ring with alternating diameter exhaust through-holes between a lid and a showerhead plate, coupled with an actuator device, allows for dynamic alignment of through-holes to optimize gas residence time during pulsing and purging steps, enhancing the efficiency of gas flow regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a common showerhead assembly with limited exhaust path is used, then the structure is simple, but the purge efficiency is insufficient and cannot achieve effective purging within desired time
Solution Approach 1:
The showerhead assembly is segmented into multiple functional components: a lid with exhaust channel, a showerhead plate with process gas holes, and an annular flow ring with alternating diameter exhaust holes. This segmentation allows each component to be optimized independently for its specific function while collectively achieving high purge efficiency.
Solution Approach 2:
The annular flow ring is made rotatable about the central axis, allowing dynamic adjustment of the exhaust hole alignment with the showerhead plate holes. The actuator device enables the flow ring to rotate between at least two positions, dynamically optimizing the exhaust path configuration based on process requirements.
2Duration of action of moving object
If the exhaust path is limited in common showerhead assemblies, then the manufacturing is simpler, but the gas residence time cannot be optimized during pulsing steps
Solution Approach 1:
The rotatable annular flow ring creates dynamic exhaust paths that can be adjusted during different process steps. During pulsing steps, the flow ring position is adjusted to optimize gas residence time by controlling the alignment between exhaust holes and showerhead plate holes, thereby regulating the exhaust path length and effectiveness.
Solution Approach 2:
The exhaust holes in the annular flow ring alternate between first and second diameters, providing variable exhaust path parameters. This parameter variation allows optimization of gas flow characteristics and residence time by selecting appropriate hole diameters for different process requirements.
3Productivity
If a static showerhead design is used, then the device complexity is lower, but the throughput is reduced due to inability to rapidly purge excess gases
Solution Approach 1:
The actuator device enables rapid rotation of the annular flow ring between different positions, allowing quick transition between pulsing and purging modes. This dynamic adjustment capability significantly reduces purge time and increases process throughput by enabling rapid removal of excess gases.
Solution Approach 2:
The system operates in periodic cycles, alternating between pulsing steps (with optimized gas residence time) and purging steps (with maximized exhaust flow). The actuator device synchronizes the flow ring position changes with these periodic process steps, achieving efficient cyclic operation that enhances overall throughput.
Data Source
AI summary
Showerhead assemblies and semiconductor processing systems including showerhead assemblies are disclosed. The showerhead assemblies disclosed include a lid, a showerhead plate, and an annular flow ring disposed between the lid and the showerhead plate. Methods for regulating gas flow to and from a reaction chamber when performing a process are disclosed. The methods disclosed include positioning an annular flow ring at first position and a second position.