Film Deposition Turntable Cleaning via Vacuum Port Switching
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Solution Overview
Problem
In film deposition processes, the introduction of a separation gas to prevent mixing of reaction gases can dilute the source gas, reducing across-the-wafer uniformity and increasing costs, while the cleaning process is hindered by the layout of gas nozzles, leading to reduced cleaning efficiency and potential damage to the apparatus.
Innovation Solution
A film deposition apparatus with a cleaning gas supplying portion positioned to terminate evacuation from the first vacuum evacuation port and perform evacuation from the second vacuum evacuation port, allowing for effective cleaning of the turntable by directing the cleaning gas flow, while maintaining the separation of reaction gases and preventing damage to the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separation gas is introduced into a source gas supplying area to prevent mixing of reaction gases, then the separation of reaction gases is improved, but the source gas is diluted reducing across-the-wafer uniformity and increasing cost
Solution Approach 1:
The gas supplying area is divided into multiple independent nozzles (first source gas nozzle, second source gas nozzle, separation gas nozzle) with distinct gas supply ports. Each nozzle can supply gas independently, allowing precise control of gas distribution patterns to maintain separation while avoiding dilution in critical areas.
Solution Approach 2:
Different regions of the gas supplying area provide different gas types through specifically positioned nozzles. The separation gas is supplied locally at boundaries between reaction gas zones, while source gas is supplied centrally, creating non-uniform but optimized gas distribution that prevents mixing without diluting the source gas in deposition areas.
2Manufacturing precision
If a flow regulating plate is provided on a gas nozzle to suppress introduction of separation gas into source gas supplying area, then the dilution of source gas is reduced, but the cleaning gas flow is also blocked reducing cleaning efficiency
Solution Approach 1:
The system dynamically switches between deposition mode and cleaning mode operations. During deposition, the flow regulating plate is in position to control gas flow and prevent dilution. During cleaning, the plate is repositioned to allow cleaning gas to reach the turntable effectively, thus adapting the flow control mechanism to different operational requirements.
Solution Approach 2:
The flow regulating plate periodically changes its position between deposition and cleaning cycles. It blocks the gas path during deposition to maintain source gas concentration, then opens the path during cleaning to allow cleaning gas flow, creating a periodic action that satisfies both contradictory requirements at different times.
3Reliability
If the cleaning gas supplying portion is positioned apart from the passing area to prevent damage to the monitor, then the reliability of the monitor is improved, but the cleaning gas flow to the turntable is reduced increasing cleaning time
Solution Approach 1:
The cleaning gas nozzle is positioned at a different spatial location (apart from the passing area) but utilizes the turntable rotation to deliver cleaning gas to all surfaces. By changing the dimensional approach from direct overhead positioning to peripheral positioning with rotational distribution, the monitor is protected while complete cleaning coverage is achieved.
Solution Approach 2:
The cleaning gas supply system serves multiple functions: it protects the monitor from damage by positioning away from the passing area, and it effectively cleans the entire turntable surface by utilizing turntable rotation to distribute the cleaning gas, thus achieving both monitor protection and efficient cleaning.
4Productivity
If the evacuation from the first vacuum evacuation port is terminated during cleaning to direct cleaning gas flow, then the cleaning efficiency is improved, but the vacuum maintenance is compromised
Solution Approach 1:
The vacuum evacuation system operates periodically, switching between the first and second vacuum evacuation ports. During cleaning operations, evacuation from the first port is terminated while the second port continues operation, creating a periodic pattern that optimizes cleaning gas flow while maintaining vacuum through the second port.
Solution Approach 2:
The vacuum evacuation function is segmented into two independent ports with different roles. The first port is dedicated to maintaining vacuum during deposition, while the second port handles evacuation during cleaning operations, allowing each port to be optimized for its specific function without compromising overall system performance.
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 configuration enhances the cleaning process efficiency, reduces the cleaning time, and minimizes the cost of cleaning gas usage, thereby improving the productivity and reducing operational costs of the film deposition apparatus.
Implementation Method 1
a plurality of wafers mounted on a turntable are rotated by the turntable to alternately pass through a plurality of reaction gas supplying areas
Implementation Method 2
separation areas, to which a separation gas which is an inert gas such as nitrogen gas or the like is provided, are provided between the plurality of the reaction gas supplying areas in a rotation direction of the turntable for preventing mixing of the plurality of reaction gasses
Implementation Method 3
vacuum evacuation ports are provided on a downstream side of the reaction gas supplying areas in the rotation direction of the turntable to evacuate the reaction gasses together with the separation gas
Implementation Method 4
a source gas that is adsorbed on a surface of the wafer
Implementation Method 5
a gas that oxidizes or nitrizes the source gas
Implementation Method 6
a reaction product is deposited by alternately supplying a plurality of kinds of reaction gasses capable of reacting with each other on a surface of a semiconductor wafer
Implementation Method 7
it is necessary to periodically remove the thin film formed on the turntable by a cleaning gas
Data Source
AI summary
A method of operating a film deposition apparatus including a turntable provided in a vacuum chamber and configured to rotate a substrate mounted thereon, a first reaction gas supplying portion, a second reaction gas supplying portion, a separation area, a first vacuum evacuation port for mainly evacuating the first reaction gas, a second vacuum evacuation port for mainly evacuating the second reaction gas, and a cleaning gas supplying portion for supplying a cleaning gas to clean the turntable, the method includes a cleaning step of supplying the cleaning gas from the cleaning gas supplying portion into the vacuum chamber while terminating the evacuation from the first vacuum evacuation port and performing the evacuation from the second vacuum evacuation port.