Off-Centered Turntable Mounting for Wafer Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional substrate processing apparatuses face issues with throughput reduction and in-plane temperature variations, leading to particle adhesion and non-uniform film deposition due to wafer warping and uneven heating during the deposition process.
Innovation Solution
A substrate processing apparatus with a turntable featuring a circular concave portion larger than the substrate and an off-centered mounting table, which prevents direct contact between the wafer's outer edge and the turntable, reducing particle generation and ensuring uniform gas distribution for consistent film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the wafer mounting surface is positioned to prevent rubbing between the wafer and turntable, then particle adhesion is reduced, but throughput is lowered due to delayed rotation of warped wafers
Solution Approach 1:
The mounting table is positioned off-center relative to the turntable rotation axis, creating an asymmetric configuration. This allows the outer peripheral end of the mounting table to extend closer to the outer edge of the wafer on one side, preventing direct contact between the wafer and turntable during rotation, thereby reducing particle generation while maintaining throughput.
2Manufacturing precision
If the wafer mounting surface contacts the turntable to ensure stability, then positioning accuracy is improved, but in-plane temperature uniformity deteriorates due to warping
Solution Approach 1:
The mounting table serves as an intermediary structure between the turntable and the wafer. It provides a stable mounting surface for positioning the wafer accurately while elevating the wafer slightly above the turntable surface, preventing direct contact. This intermediary structure maintains positioning accuracy while allowing warped wafers to be rotated without causing temperature non-uniformity through friction or uneven heating.
3Object-generated harmful factors
If the outer peripheral end of the mounting table extends beyond the wafer edge, then particle generation is prevented, but device complexity increases
Solution Approach 1:
The mounting table is designed with local quality variation, where the outer peripheral end extends beyond the wafer edge in the radial direction to prevent particle generation, while the central region maintains a configuration suitable for wafer mounting. This localized extension only where needed minimizes the overall structural complexity while achieving the particle prevention goal.
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 throughput by allowing immediate rotation of warped wafers, reduces particle adhesion, and maintains in-plane process uniformity, even when wafers are initially at room temperature or have undergone prior heat treatments.
Implementation Method 1
when the substrate is moved by centrifugal force, the peripheral edge portion of the substrate protruding from the mounting table along the circumferential direction of the substrate
Data Source
AI summary
A substrate processing apparatus includes a vacuum chamber; a turntable rotatably provided in the vacuum chamber, on which a circular substrate is to be mounted, and provided with a circular concave portion at a front surface having a larger diameter than that of the substrate, and a circular substrate mounting portion provided in the concave portion having a diameter smaller than that of the concave portion and the substrate at a position higher than a bottom portion of the concave portion, the center of the substrate mounting portion being off center with respect to the center of the concave portion toward an outer peripheral portion side of the turntable; a process gas supplying unit which supplies a process gas to the substrate; and a vacuum evacuation mechanism which evacuates the vacuum chamber.