Turntable Locking Mechanism for ALD Wafer Stability
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Solution Overview
Problem
Current film deposition techniques using Atomic Layer Deposition (ALD) methods face challenges in achieving high throughput due to long process times and maintenance requirements, particularly when using a rotatable susceptor, as they struggle to maintain reaction gas concentration and prevent wafer floating during high-speed rotation, leading to reduced film uniformity and increased contamination.
Innovation Solution
A film deposition apparatus with a turntable that includes separate reaction gas supplying portions, a separation area between them, and a locking mechanism to prevent wafer floating, along with an inert gas supply and evacuation system to maintain pressure differences and secure the wafer, allowing for efficient alternation of reaction gases and improved film uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the turntable rotates at high speed to increase throughput, then productivity is improved, but the wafer floats and vibrates causing reduced manufacturing precision and increased contamination
Solution Approach 1:
The patent applies counterbalancing forces to offset the harmful effects of high-speed rotation. Specifically, the locking mechanism provides a counteracting force to prevent wafer floating caused by centrifugal force, while the separation gas flow creates a counter-pressure to stabilize the wafer position, thereby maintaining film uniformity during high-speed operation
Solution Approach 2:
The patent introduces a separation gas as an intermediary substance between the reaction gases and the wafer. This separation gas forms a protective layer that stabilizes the wafer during high-speed rotation, preventing direct contact with reaction gases and reducing vibration-induced contamination while maintaining deposition quality
2Productivity
If the turntable rotates at high speed to increase throughput, then productivity is improved, but contamination increases due to wafer floating and vibration
Solution Approach 1:
The separation gas acts as an intermediary barrier between the wafer and the reaction gases during high-speed rotation. This intermediary gas layer prevents direct contamination from reaction gases while the locking mechanism prevents physical contamination from wafer movement, enabling high-speed operation without increased contamination
Solution Approach 2:
The patent converts the harmful centrifugal force generated by high-speed rotation into a beneficial stabilizing effect. By carefully controlling the separation gas flow rate, the gas pressure differential created by rotation is used to press the wafer firmly against the turntable surface through the locking mechanism, transforming the floating tendency into a stabilizing force
3Reliability
If the reaction chamber is fully evacuated to prevent gas intermixture, then reliability is improved, but the process time increases significantly
Solution Approach 1:
The patent segments the reaction chamber into multiple independent process areas separated by physical partitions and sealed by the separation gas layer. This segmentation allows different reaction gases to be supplied simultaneously to different areas without intermixture, eliminating the need for repeated evacuation cycles and significantly reducing process time while maintaining gas separation reliability
Solution Approach 2:
The separation gas serves as an intermediary barrier that prevents direct intermixture between reaction gases in adjacent process areas. This intermediary layer allows simultaneous gas supply to multiple areas without requiring full chamber evacuation, thereby maintaining reliable gas separation while dramatically reducing the time lost to evacuation cycles
4Manufacturing precision
If a locking mechanism is added to prevent wafer floating, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is designed to be self-activating through the centrifugal force generated by turntable rotation. As the turntable rotates, the centrifugal force automatically engages the locking mechanism to secure the wafer, eliminating the need for external actuators or complex control systems while maintaining precise wafer positioning during high-speed operation
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 apparatus effectively prevents wafer floating and vibration, reduces contamination, and enhances film deposition uniformity, thereby increasing production yield and throughput while minimizing maintenance needs.
Implementation Method 1
a turntable (2) provided in the vacuum chamber (1)
Implementation Method 2
a center area (C) that is located at substantially a center of the vacuum chamber (1) and has an ejection hole through which a separation gas is ejected to the surface where the substrate receiving portion (24) is provided in the turntable (2), thereby separating the atmospheres of the first process area (P1) and the second process area (P2)
Implementation Method 3
by performing a cycle of alternately supplying at least two kinds of reaction gases that react with each other on the substrate to produce a layer of a reaction product
Implementation Method 4
a first reaction gas is adsorbed on a surface of a semiconductor wafer (referred to as a wafer hereinafter) under vacuum and then a second reaction gas is adsorbed on the surface of the wafer in order to form one or more atomic or molecular layers through reaction of the first and the second reaction gases on the surface of the wafer
Implementation Method 5
a locking member (18) that locks a part of an upper surface of the substrate (W) in order to keep the substrate (W) in the substrate receiving portion (24) of the turntable (2)
Implementation Method 6
an elevation mechanism that moves the locking member (18) and the substrate (W) upward and downward from the turntable (2)
Implementation Method 7
in a vacuum chamber (1)
Data Source
AI summary
A film deposition apparatus for depositing a film on a substrate by performing a cycle of alternately supplying at least two kinds of reaction gases that react with each other on the substrate to produce a layer of a reaction product in a vacuum chamber is disclosed. The film deposition apparatus includes a ring-shaped locking member that may be provided in or around a wafer receiving portion of a turntable in which the substrate is placed, in order to keep the substrate in the substrate receiving portion.