Rotating Gas Showerhead for Wafer Processing
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Solution Overview
Problem
Conventional gas showerheads for semiconductor wafers face challenges in maintaining a controlled atmosphere and efficiently utilizing process gas, particularly when used with magnetic rotor chucks that lack conventional gas seals.
Innovation Solution
A rotating gas showerhead with a domed outlet plate and inclined discharge openings is integrated with a spin chuck, featuring a gas distribution chamber and a blocking gas feed to confine process gas, ensuring efficient delivery and preventing gas escape through the gap between the rotor and chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional gas showerhead is used with a magnetic rotor chuck, then the wafer can be processed, but the process gas cannot be efficiently confined and escapes through the gap between the rotor and chamber
Solution Approach 1:
The gas showerhead is made rotatable to match the dynamic operation of the magnetic rotor chuck, allowing the gas distribution chamber to rotate with the rotor and maintain effective gas confinement throughout the wafer processing cycle
Solution Approach 2:
The gas distribution chamber is nested within the rotating gas showerhead structure, with the chamber positioned to contain process gas close to the wafer surface while the showerhead rotates around the rotor-chamber assembly
2Quantity of substance
If the gas distribution chamber is made larger to improve gas distribution, then gas coverage increases, but gas loss through the rotor-chamber gap increases
Solution Approach 1:
The gas distribution chamber is designed with localized gas delivery features including multiple gas distribution holes positioned at specific locations to target gas delivery precisely where needed on the wafer surface, rather than using a uniform large-volume chamber
Solution Approach 2:
The gas distribution holes are arranged in multiple layers at different heights within the chamber, creating a three-dimensional gas distribution pattern that improves coverage while maintaining compact chamber dimensions
3Productivity
If the outlet plate is positioned closer to the wafer to improve gas contact, then process efficiency increases, but liquid accumulation in the chamber increases
Solution Approach 1:
The outlet plate is designed with a domed curved surface rather than a flat plate, which prevents liquid accumulation by allowing liquids to drain away from the gas distribution holes while maintaining close proximity to the wafer for effective gas contact
Solution Approach 2:
The domed outlet plate creates an asymmetric geometry where the curved surface orientation promotes liquid drainage in specific directions away from the gas distribution holes, preventing liquid buildup that would otherwise occur with a symmetric flat plate
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 effectively maintains a controlled atmosphere and enhances process gas efficiency by confining gas within the distribution chamber, ensuring it contacts the wafer surface while diverting liquids and reducing gas loss.
Implementation Method 1
A process gas feed is provided so as to supply process gas to a gas distribution chamber. The gas distribution chamber is in fluid communication with a plurality of openings formed in the shower head.
Implementation Method 2
a spin chuck for holding a wafer-shaped article in a predetermined orientation
Implementation Method 3
the spin chuck is a magnetic rotor, and the apparatus further comprises a magnetic stator surrounding the magnetic rotor.
Data Source
AI summary
An apparatus for processing wafer-shaped articles comprises a spin chuck for holding a wafer-shaped article in a predetermined orientation, and a rotating shower head for supplying process gas to a surface of a wafer-shaped article when held by the spin chuck. The rotating shower head comprises an outlet plate having plural openings formed in each of a central and a peripheral region thereof. A process gas feed is provided so as to supply process gas to a gas distribution chamber. The gas distribution chamber is in fluid communication with a plurality of openings formed in the shower head.