Heated Showerhead Assembly for Plasma Etching Uniformity
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Solution Overview
Problem
The conventional plasma etch process in integrated circuit manufacturing faces non-uniformity issues due to uneven gas distribution across the substrate, caused by the vacuum pump drawing etching gas towards the exhaust port, leading to performance and cost challenges.
Innovation Solution
A heated showerhead assembly is introduced, divided into two zones with independently controllable gas introduction and temperature control, where the inner zone corresponds to the substrate's perimeter and the outer zone to its center, ensuring uniform gas distribution and plasma uniformity by compensating for uneven vacuum draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional plasma etch process is used with a single gas distribution system, then the structure is simple, but the etch rate uniformity across the substrate deteriorates due to vacuum pump drawing gas toward the exhaust port
Solution Approach 1:
The gas distribution system is divided into two separate zones: a first gas distribution system for the first substrate region and a second gas distribution system for the second substrate region. Each zone has independent gas flow control, allowing separate optimization of etch rate uniformity in different areas without affecting the other zone
Solution Approach 2:
Each substrate region receives gas through dedicated distribution channels tailored to its specific requirements. The first region has first distribution channels with specific flow characteristics, while the second region has second distribution channels with different flow characteristics, allowing local optimization of gas flow to compensate for position-dependent vacuum effects
2Productivity
If the vacuum pump draws etching gas toward the exhaust port, then gas evacuation efficiency is improved, but gas distribution uniformity across the substrate deteriorates
Solution Approach 1:
The patent implements different gas distribution characteristics for different substrate regions. Regions closer to the exhaust port receive gas through channels designed to compensate for the stronger vacuum draw, while regions farther away have different channel configurations, ensuring uniform gas distribution across the entire substrate despite varying vacuum forces
Solution Approach 2:
The gas flow parameters (flow rate, pressure, channel dimensions) are varied across different zones of the substrate to compensate for the non-uniform vacuum field. By adjusting these parameters locally, the system maintains consistent gas delivery to all regions while preserving the vacuum pump's evacuation efficiency
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 enhances etching uniformity across the substrate, improving the yield and reducing fabrication costs by maintaining consistent plasma distribution and gas flow, even at the substrate's center and perimeter.
Implementation Method 1
a heating element coupled with a heating source... the heating element may be disposed within the first zone and within the second zone
Data Source
AI summary
The present disclosure generally comprises a heated showerhead assembly that may be used to supply processing gases into a processing chamber. The processing chamber may be an etching chamber. When processing gas is evacuated from the processing chamber, the uniform processing of the substrate may be difficult. As the processing gas is pulled away from the substrate and towards the vacuum pump, the plasma, in the case of etching, may not be uniform across the substrate. Uneven plasma may lead to uneven etching. To prevent uneven etching, the showerhead assembly may be separated into two zones each having independently controllable gas introduction and temperature control. The first zone corresponds to the perimeter of the substrate while the second zone corresponds to the center of the substrate. By independently controlling the temperature and the gas flow through the showerhead zones, etching uniformity of the substrate may be increased.