Ceramic Gas Nozzle Roughness Gradient for Low-Particle Plasma Flow
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Solution Overview
Problem
Existing gas nozzles in semiconductor manufacturing suffer from increased gas flow resistance and particle generation due to abrasive particles adhering to the inner surface and the elongated supply hole design, which can damage fine memory wiring lines when using corrosive gases in plasma treatment processes.
Innovation Solution
A gas nozzle with a tubular supply hole and connecting injection hole made from ceramics or single crystals, featuring a rare earth element or yttrium aluminum composite oxide as the primary component, and an arithmetic mean roughness of the inner surface that decreases from the inflow to the outflow side to reduce gas flow resistance and particle generation, manufactured through pressing, molding, machining, and polishing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blasting processing is employed to roughen the outer surface of the gas nozzle, then corrosion resistance is improved, but abrasive particles adhere to the inner surface and generate fine particles in the plasma space
Solution Approach 1:
The patent applies different surface roughness characteristics to different locations within the supply hole. The inner circumferential surface has a controlled roughness profile with smaller arithmetic mean roughness Ra on the outflow side compared to the inflow side. This local differentiation allows the surface to maintain corrosion resistance while reducing particle generation in the critical outflow region where particles could enter the plasma space.
2Ease of operation
If the supply hole is made elongated to guide gas flow, then gas distribution is improved, but gas flow resistance increases and particles are generated from the inner circumferential surface
Solution Approach 1:
The patent changes the surface roughness parameter along the length of the supply hole to optimize gas flow. By making the arithmetic mean roughness Ra smaller on the outflow side compared to the inflow side, the surface characteristics are adjusted to reduce flow resistance in the critical region while maintaining adequate gas distribution throughout the elongated hole structure.
3Object-generated harmful factors
If the inner surface roughness is increased to reduce particle adhesion, then particle generation is reduced, but gas flow resistance increases
Solution Approach 1:
Rather than uniformly increasing roughness throughout the supply hole, the patent applies a gradient approach where the arithmetic mean roughness Ra is smaller on the outflow side compared to the inflow side. This local quality differentiation reduces particle generation in the outflow region while minimizing the negative impact on gas flow resistance.
Data Source
AI summary
A gas nozzle according to the present disclosure includes a supply hole having a tubular shape and configured to guide a gas and an injection hole connecting to the supply hole. The gas nozzle configured to inject the gas from the injection hole is made from ceramics or single crystal including an oxide, a fluoride, or an oxyfluoride of a rare earth element or an yttrium aluminum composite oxide as a primary component. An arithmetic mean roughness Ra of an inner circumferential surface forming the supply hole is smaller on an outflow side than on an inflow side of the gas.