Focus Ring Detection via Stage Through Hole
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Solution Overview
Problem
Existing substrate processing technologies lack an effective method to detect the presence and absence of a focus ring on a stage, leading to potential errors and inefficiencies in substrate processing due to ambient light interference and the inability to accurately determine the focus ring's presence.
Innovation Solution
A substrate processing apparatus and method utilizing a light source, optical assembly, and controller to focus light on the lower surface of a focus ring and detect its presence or absence based on the received light, with a through hole and transmitting member to minimize ambient light interference and allow for accurate detection without increasing the apparatus' footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a light source and receiver are used to detect the focus ring, then detection capability is improved, but ambient light interference reduces measurement precision
Solution Approach 1:
The patent introduces a through hole in the stage as an intermediary optical path that allows light to pass through from below the stage to illuminate the focus ring's lower surface. This mediator enables selective illumination of the focus ring while blocking ambient light from above, resolving the contradiction between detection capability and precision by creating a controlled optical environment.
Solution Approach 2:
The patent applies local quality by focusing light specifically on the lower surface of the focus ring through the through hole, rather than illuminating the entire stage area. This localized illumination improves measurement precision by reducing ambient light interference in the detection area while maintaining effective focus ring detection.
2Measurement precision
If a through hole and transmitting member are added to the stage, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The through hole in the stage serves multiple functions: it acts as an optical channel for light transmission, provides structural support for the transmitting member, and enables the detection system to differentiate between the focus ring and ambient light. By making the stage structure multi-functional, the patent improves detection accuracy without proportionally increasing device complexity.
Solution Approach 2:
The stage structure itself provides the optical channel function through the through hole, eliminating the need for separate complex illumination structures. The transmitting member utilizes the existing stage geometry to guide light, allowing the system to achieve improved detection accuracy while minimizing additional structural complexity.
3Reliability
If light is focused on the lower surface of the focus ring, then detection reliability is improved, but the apparatus footprint increases
Solution Approach 1:
The patent changes the detection dimension by illuminating the focus ring from below through the through hole, rather than approaching from the top. This dimensional change allows the optical components to be positioned in the vertical direction, reducing the horizontal footprint while maintaining reliable focus ring detection through focused illumination of the lower surface.
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
Enables accurate detection of the focus ring's presence, reducing errors and improving processing efficiency by distinguishing between the focus ring and ambient light reflections, while maintaining a compact apparatus design.
Implementation Method 1
The optical assembly adjustably focuses light from the light source substantially on a lower surface position, which is a position of a lower surface of the focus ring placed on the second placing surface
Implementation Method 2
The light receiver receives light from the lower surface position
Data Source
AI summary
A substrate processing apparatus includes a stage, a light source, an optical assembly, a light receiver, and controller circuitry. The stage includes a first placing surface on which a substrate is to be placed, and a second placing surface that surrounds the first placing surface and on which a focus ring is to be placed. The optical assembly focuses light from the light source on a lower surface position, which is a position of a lower surface of the focus ring placed on the second placing surface. The light receiver receives light from the lower surface position. The controller circuitry detects at least one of a presence and an absence of the focus ring on the second placing surface, based on light received by the light receiver.