CMP Apparatus Film Thickness Sensor Mapping
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) technologies face challenges in achieving accurate film thickness distribution and uniformity across the wafer surface due to variations in initial film thickness and polishing, leading to suboptimal results in semiconductor manufacturing.
Innovation Solution
A polishing apparatus equipped with multiple film thickness sensors embedded in the polishing table, a controller for analyzing and visualizing film thickness distribution, and a pressing force controller to adjust polishing pressure based on real-time film thickness data, allowing for precise control of the polishing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single film thickness sensor is used to measure wafer thickness, then the device complexity is low, but the measurement precision and film thickness distribution accuracy are insufficient
Solution Approach 1:
The polishing table is divided into multiple regions with film thickness sensors arranged at different radial positions (inner region, middle region, outer region). Each sensor measures film thickness at its specific location, enabling comprehensive mapping of the wafer's film thickness distribution without requiring a single complex sensor system.
2Measurement precision
If film thickness sensors are arranged only at the outer edge to detect notch position, then the device complexity is low, but the film thickness distribution information across the entire wafer surface is insufficient
Solution Approach 1:
The measurement system transitions from one-dimensional edge detection to two-dimensional surface mapping by arranging sensors at multiple radial positions (inner, middle, outer regions) and angular positions. This dimensional expansion enables comprehensive acquisition of film thickness distribution across the entire wafer surface, not just at the edge.
Solution Approach 2:
The notch position is detected in advance using the outer region sensor before full film thickness measurement begins. This preliminary detection allows the system to establish a reference point for subsequent measurements, enabling accurate correlation of film thickness data with specific wafer positions during rotation.
3Manufacturing precision
If uniform polishing pressure is applied across the wafer surface, then the device complexity is low, but the manufacturing precision of film thickness uniformity deteriorates due to variations in initial film thickness
Solution Approach 1:
The polishing head applies different pressures to different regions of the wafer based on real-time film thickness measurements from sensors at inner, middle, and outer regions. Areas with thicker initial film receive higher polishing pressure, while areas with thinner film receive lower pressure, enabling localized control of material removal to achieve uniform final film thickness across the wafer surface.
Solution Approach 2:
The system continuously monitors film thickness at multiple positions during polishing and uses this feedback information to dynamically adjust the polishing pressure distribution. The measured film thickness data from different radial regions is fed back to the pressure control system, which modifies the pressure applied to each region to compensate for variations in initial film thickness and achieve uniform polishing results.
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 enables accurate acquisition and visualization of film thickness distribution, improving the uniformity of the wafer surface by actively adjusting polishing pressure, thereby enhancing the yield and quality of semiconductor manufacturing.
Implementation Method 1
a signal corresponding to a film thickness of the substrate is obtained from a film thickness sensor
Data Source
AI summary
A polishing apparatus capable of acquiring accurate film thickness distribution information is disclosed. The polishing apparatus includes a polishing table, a plurality of film thickness sensors, and a controller. The controller analyzes film thickness distribution information of a substrate while identifying a notch position of the substrate based on the measured film thickness information, and outputs visualization information of the film thickness distribution with the notch position as a reference position.