Wafer Misplacement Detection Using Dual-Sensor Temperature Profiles
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Solution Overview
Problem
In mainframe processing chambers, poor process uniformity and frequent wafer breakage occur due to the lack of feedback on proper wafer placement, leading to wafers being misplaced outside the substrate support regions during rotation, which is inefficient and time-consuming.
Innovation Solution
A processing chamber equipped with a support assembly and sensors to determine if a substrate is within the substrate support regions by measuring temperature profiles at different distances from the central rotational axis, using a first and second sensor positioned at varying distances, and a controller to assess the substrate's position based on these profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wafers are rotated during processing to improve uniformity, then within-wafer uniformity is improved, but processing time increases and additional hardware space is required
Solution Approach 1:
The patent implements a compromise rotation approach where wafers are rotated only partially (e.g., 90 degrees or 180 degrees) rather than completing full 360-degree rotations. This partial rotation is sufficient to improve within-wafer uniformity by exposing different regions to the processing environment, while avoiding the time penalty and space requirements of complete rotation cycles. The support assembly rotates wafers to predetermined angular positions without requiring full circular motion.
2Productivity
If multiple wafers are placed on a susceptor for batch processing, then throughput is improved, but the risk of wafer misplacement and breakage increases
Solution Approach 1:
The patent incorporates sensors (such as capacitive, inductive, or optical sensors) that provide real-time feedback on wafer placement status. These sensors detect whether wafers are correctly positioned within substrate support regions on the rotating support assembly. The controller receives this feedback signal and can immediately identify misplaced wafers, alert operators, or adjust positioning mechanisms to correct the error before processing begins, thereby preventing wafer breakage while maintaining batch processing efficiency.
3Productivity
If wafers are placed outside the substrate support region, then loading efficiency is improved, but wafer breakage occurs during rotation
Solution Approach 1:
Sensors positioned near the substrate support regions provide feedback signals that indicate whether wafers are correctly placed within the support regions or outside them. The controller processes these signals to identify misplaced wafers before the rotation cycle begins, allowing for corrective action to be taken while maintaining efficient loading procedures.
Solution Approach 2:
The system performs preliminary detection of wafer placement status before the rotation process begins. The sensors scan the positions of wafers on the support assembly and identify any that are outside the substrate support regions. This preliminary detection allows operators or automated systems to correct placement errors before rotation starts, preventing the harmful effect of wafer breakage during the processing cycle.
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 solution enhances process uniformity by accurately detecting misplaced wafers and preventing breakage, improving throughput and reducing the need for additional hardware or space, thereby ensuring more efficient and reliable wafer processing.
Implementation Method 1
measuring a first temperature profile comprising temperature at a first distance from the central rotational axis as a function of rotational angle of the support assembly using a first sensor; measuring a second temperature profile comprising temperature at a second distance from the central rotational axis as a function of rotational angle of the support assembly using a second sensor
Data Source
AI summary
Apparatus and methods to process one or more substrate are described. A processing chamber comprises a support assembly, a chamber lid, and a controller. The chamber lid has a front surface facing the support assembly, a first sensor on the front surface and a second sensor on the front surface, the first sensor positioned at a first distance from the central rotational axis, and the second sensor positioned at a second distance from the central rotational axis greater than the first distance. The controller is configured to determine if a substrate is within or outside of the substrate support region of the support assembly.