Low-Profile Optical Gap Measurement in Plasma Processing Chambers
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Solution Overview
Problem
Existing systems face challenges in accurately measuring the gap between a workpiece and a nearby object in constrained environments, such as a plasma processing chamber, without interfering with robot operations or plasma distribution, particularly in semiconductor manufacturing where precision is crucial.
Innovation Solution
A contactless measurement system using low-profile assemblies that project electromagnetic beams to determine the gap between a workpiece and a nearby object, employing image processing to calculate the gap even when the workpiece surface is close to the nearby object's top surface, with a central control unit and imaging sensors to ensure precise measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contactless measurement system is introduced to measure the gap between workpiece and nearby object, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical contact-based measurement systems with a contactless optical measurement system. The system uses a light source to project light along a measurement axis and detects the position of the nearby object through light reflection or transmission, eliminating the need for physical contact probes and reducing mechanical complexity while achieving high measurement precision.
Solution Approach 2:
The patent introduces light as an intermediary medium to transfer measurement information between the measurement system and the nearby object. The light source projects light along the measurement axis, and the light interaction with the object (reflection, transmission, or scattering) provides measurement data without direct contact, enabling non-invasive precision measurement.
2Adaptability or versatility
If the measurement system operates in a constrained environment like a plasma processing chamber, then measurement capability is improved, but ease of operation deteriorates due to interference with robot operations and plasma distribution
Solution Approach 1:
The patent positions the light source and detector at specific locations on the workpiece holder, utilizing the local space between the workpiece and the nearby object (such as a focus ring) for measurement. This localized measurement approach does not interfere with overall plasma distribution or robot operations in the chamber, as the measurement components are confined to a small region.
Solution Approach 2:
The patent measures the gap dimension (distance between workpiece and nearby object) by projecting light along a measurement axis that is perpendicular to the workpiece surface. This dimensional approach allows measurement in the vertical gap space without occupying horizontal space needed for robot operations, effectively utilizing a different spatial dimension for measurement.
3Manufacturing precision
If the workpiece surface is positioned close to the top surface of the nearby object, then manufacturing precision is improved, but measurement precision deteriorates due to difficulty in detecting the gap
Solution Approach 1:
The patent replaces mechanical contact probes with optical detection methods to measure the gap. The light source projects light along the measurement axis toward the nearby object, and the detection system measures light intensity variations or position changes to determine the gap distance, achieving high precision measurement even when the gap is very small.
Solution Approach 2:
The patent changes the measurement parameter from mechanical displacement to optical intensity or position. By detecting changes in light intensity or light position as the workpiece moves relative to the nearby object, the system achieves high sensitivity in measuring small gap variations, improving measurement precision for closely positioned surfaces.
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 and precise gap measurement in constrained environments, allowing for improved plasma processing uniformity and monitoring of object degradation, thereby enhancing semiconductor manufacturing quality and reducing yield loss.
Implementation Method 1
an assembly comprising a main axis directed to a first direction and approximately parallel to the surface of the workpiece to intersect the inner surface of a nearby object. The assembly includes at least one projector for projecting an electromagnetic beam onto the inner surface of the nearby object
Data Source
AI summary
Provided are system and method for contactless precision measurement of the position of the system relative to a nearby object and for monitoring a degradation of the nearby object edge. The system comprises a workpiece, at least one assembly, and a central control unit. The assembly comprises a main axis directed to a first direction and approximately parallel to the surface of the workpiece to intersect the inner surface of the object. The assembly further comprises at least one projector for projecting an electromagnetic beam onto the object for the measurement. Both the assembly and the central control unit are attached on the surface of the workpiece at desired locations. The entire system is configured to have a low profile, with all beam paths constrained within the system's overall height, and the system can be operated stand alone in an enclosed and dimensional constrained operation environment.