Plasma Showerhead Thin-Film Lining for Particle Control
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Solution Overview
Problem
Existing showerheads used in high charge and plasma density microwave plasma processes contribute to defect and particle generation due to thick coatings formed inside gas openings during plasma-enhanced ALD processes, leading to yield loss in semiconductor manufacturing.
Innovation Solution
A method involving the use of a silicon-containing precursor and reactant gas to form a thin film of silicon oxide or silicon nitride on the showerhead's faceplate and gas openings, followed by a first plasma to initiate film formation and a second plasma to densify the film, ensuring precise control over film thickness and preventing particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick coating is formed inside gas openings during plasma-enhanced ALD processes, then the showerhead provides adequate protection and coverage, but particle and defect generation increases leading to yield loss
Solution Approach 1:
The patent changes the physical and chemical parameters of the coating process by using plasma-enhanced deposition to create a thin film with controlled thickness, composition, and density. By adjusting plasma power, pressure, and gas flow rates, the process forms a coating that is thin enough to prevent particle generation but sufficient to protect the showerhead, resolving the contradiction between protection and defect prevention
Solution Approach 2:
The patent applies different coating conditions to different regions of the showerhead. The gas openings receive a controlled thin film deposition that prevents particle generation, while other areas may receive different coating thicknesses or compositions. This localized control allows the coating to provide protection without causing the harmful effects associated with thick coatings in the gas openings
2Manufacturing precision
If plasma density is increased to improve film quality and reduce processing temperature, then deposition quality improves, but coating thickness inside gas openings increases causing particle generation
Solution Approach 1:
The patent uses periodic or pulsed plasma application to control coating deposition. By applying plasma in controlled pulses rather than continuously, the process allows for precise control of coating thickness and density. This periodic action enables the formation of high-quality thin films that prevent particle generation while maintaining the benefits of high plasma density processing
Solution Approach 2:
The patent maintains continuous plasma exposure during the deposition process to ensure uniform and controlled film formation. The continuous plasma action allows for steady-state deposition conditions that produce consistent thin films with controlled thickness, preventing the formation of thick coatings that would lead to particle generation while maintaining high film quality
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 method reduces metal contamination and defects, maintaining acceptable levels of metal impurities and preventing particle generation, thereby enhancing the quality and yield of semiconductor device manufacturing.
Implementation Method 1
introducing a first plasma in the plasma processing chamber for a time sufficient to form a thin film selected from the group consisting of a silicon oxide thin film and a silicon nitride thin film on the lower surface of the faceplate and lining the gas openings
Implementation Method 2
introducing a second plasma in the plasma processing chamber after flowing the purge gas to remove the silicon-containing precursor from the process volume and the gas openings, wherein introducing the second plasma densifies the thin film
Data Source
AI summary
Methods of treating a plasma showerhead comprise placing a showerhead comprising a faceplate and a plurality of gas openings PECVD substrate processing chamber having a process volume between the substrate support and the faceplate, and then exposing the showerhead to a silicon-containing precursor and a reactant gas so that the process volume and the gas openings are filled with the silicon-containing precursor and the reactant gas. The method includes introducing a first plasma in the PECVD substrate processing chamber to form a silicon oxide thin film or a silicon nitride thin film on the lower surface of the faceplate and lining the gas openings. A precursor-removing purge gas is flowed and a second plasma is struck to densify the thin film.