Focus Ring Height Estimation Using Jig-Referenced Distance Sensing
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Solution Overview
Problem
Existing methods for estimating the height of annular members in substrate processing systems, such as focus rings, are inaccurate due to unevenness in the substrate placement surface, leading to variations in measurement results.
Innovation Solution
A substrate processing system that includes a distance sensor on a substrate transport mechanism to measure distances to both a reference surface on a jig substrate and the annular member, using a control device to estimate the height of the annular member based on these measurements, accounting for surface unevenness by employing multiple distance sensors and vibration compensation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single distance sensor is used to measure the height of the annular member, then the measurement process is simple, but the measurement precision is low due to surface unevenness
Solution Approach 1:
The measurement process is segmented into two distinct steps: first measuring the reference surface to establish a baseline, then measuring the annular member surface. This segmentation allows the system to account for surface unevenness by comparing the two measurements, thereby improving height measurement precision without requiring a single complex sensor system
Solution Approach 2:
The reference surface acts as an intermediary element in the measurement process. By measuring the reference surface first and using it as a reference point, the system can compensate for surface unevenness and obtain accurate height measurements of the annular member, effectively using the reference surface as a mediator between the sensor and the target object
2Measurement precision
If multiple distance sensors are used to compensate for surface unevenness, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The measurement function is segmented temporally rather than spatially - the same sensor measures the reference surface at one time, then measures the annular member at another time. This temporal segmentation achieves the effect of multiple measurements without the complexity of multiple simultaneous sensors
Solution Approach 2:
A single distance sensor is made multi-functional by using it for two different measurement purposes: first as a reference surface measurer, then as an annular member height measurer. This universal usage of one sensor achieves the precision benefits of multiple sensors while avoiding their complexity
3Measurement precision
If vibration compensation techniques are implemented, then the measurement precision improves, but the ease of operation decreases
Solution Approach 1:
The reference surface measurement is performed as a preliminary action before the actual annular member measurement. This preliminary measurement establishes a baseline that compensates for surface unevenness and vibrations, improving precision while keeping the overall process manageable through clear sequential steps
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
Accurately estimates the height of annular members, such as focus rings, by compensating for surface unevenness and vibrations, ensuring consistent and precise plasma processing results.
Implementation Method 1
a distance sensor provided in the substrate holder and configured to measure distances from the substrate holder
Implementation Method 2
the distance sensor is further configured to measure a distance from the substrate holder positioned above the stage to the reference surface of the jig substrate and a distance from the substrate holder to the annular member
Data Source
AI summary
A substrate processing system includes: a substrate processing apparatus including a stage on which a substrate and an annular member are placed; a substrate transport mechanism including a substrate holder; a distance sensor provided in the substrate holder; and a control device, wherein the substrate transport mechanism is configured to place a jig substrate having a reference surface as a reference for a height of the annular member on the stage, wherein the distance sensor is configured to measure a distance from the substrate holder positioned above the stage to the reference surface of the jig substrate and a distance from the substrate holder to the annular member, and wherein the control device is configured to estimate the height of the annular member based on a measurement result of the distance to the reference surface and a measurement result of the distance to the annular member.