Embedded-Nut Showerhead Mounting to Prevent Metal Contamination
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Solution Overview
Problem
In semiconductor processing, exposed metal materials in showerheads can lead to metal contamination on substrates, causing impurities and device failures, and existing support methods using metal screws or alloyed screws do not entirely eliminate metal exposure.
Innovation Solution
A showerhead apparatus with an embedded nut system, where a body with cavities and a cover plate minimizes exposed metal by using refractory metals or metal oxides for the nut, and a gas distribution assembly with a funnel-shaped space and base ring to secure the showerhead without direct metal exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal screws are used to support the showerhead, then the showerhead can be securely clamped, but metal contamination occurs on the substrates
Solution Approach 1:
The patent extracts the metal fastening function from the visible support structure by embedding nuts within the showerhead body cavities. Bolts are positioned outboard of the processing region, separating the fastening mechanism from the contamination-prone area while maintaining secure support.
Solution Approach 2:
The patent implements nesting by placing nuts inside cavities within the showerhead body. The nuts are embedded within the showerhead structure itself, with bolts passing through the body to engage these embedded nuts, creating a nested fastening system that eliminates exposed metal fasteners in the processing region.
2Object-affected harmful factors
If alloyed screws such as Hastelloy are used outboard of the wafer, then metal exposure is reduced, but not all potential metal exposure is eliminated
Solution Approach 1:
The patent removes metal fastening components from the processing region entirely by positioning bolts outboard of the wafer and embedding nuts within the showerhead body. This extraction ensures no metal exposure occurs within the processing region, achieving complete contamination prevention.
Solution Approach 2:
The patent introduces non-metallic materials (quartz or ceramic) as intermediaries between the metal bolts and the processing environment. These materials form the showerhead body and cover plates that encapsulate the metal fastening components, preventing any metal exposure to substrates while maintaining structural integrity.
3Object-affected harmful factors
If quartz clamps are used to support the showerhead, then metal contamination is eliminated, but the clamps are very fragile and break easily
Solution Approach 1:
The patent employs composite construction with non-metallic materials (quartz or ceramic) forming the showerhead body and cover plates. This composite structure maintains the contamination-free benefits of non-metallic materials while achieving the required mechanical strength through proper material selection and structural design.
Solution Approach 2:
The patent replicates the structural support function of metal clamps using non-metallic materials. The showerhead body and cover plates serve as both structural support elements and contamination barriers, eliminating the need for separate metal clamps while maintaining durability.
Data Source
AI summary
A showerhead with an embedded nut is disclosed. The showerhead comprises an embedded nut within a cavity. The nut may be engaged by a bolt through an opening in the cavity to support the showerhead. The apparatus allows for the support of the showerhead without the potential for metal contamination.