Eddy Current Sensor Integration for Real-Time Thickness Mapping

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Solution Overview

Problem

The efficiency of thickness measurement in chemical mechanical polishing (CMP) processes is hindered by the use of special-purpose measuring devices, leading to reduced production efficiency due to time-consuming measurements.

Innovation Solution

A substrate polishing apparatus equipped with a rotatably configured polishing table and head, featuring an eddy current sensor that outputs signals for thickness measurement, allowing for real-time calculation and creation of thickness maps to optimize polishing parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a special-purpose measuring device is used for thickness measurement, then measurement accuracy is improved, but measurement time increases and production efficiency decreases

Engineering Contradiction:

Improvethickness measurement accuracyVSAvoidproduction efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent combines the thickness measurement function with the existing CMP apparatus by integrating a sensor into the polishing table or polishing head. This allows the same equipment to perform both polishing and thickness measurement functions, eliminating the need for separate special-purpose measuring devices and reducing measurement time while maintaining accuracy.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The CMP apparatus is designed to perform multiple functions: polishing the substrate and simultaneously measuring its thickness. The sensor integrated into the polishing table or head enables the apparatus to acquire thickness information during the polishing process itself, making the equipment universal and improving production efficiency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If thickness measurement is performed using a separate measuring device, then measurement accuracy is improved, but measurement time increases

Engineering Contradiction:

Improvethickness measurement accuracyVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables continuous thickness measurement during the polishing process by integrating a sensor into the CMP apparatus. The sensor continuously monitors substrate thickness as the polishing occurs, eliminating the need to stop polishing for separate measurements and allowing real-time feedback for process control.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The thickness measurement is performed during the polishing process itself rather than after completion. By measuring thickness in real-time during polishing, the system can detect thickness variations early and adjust polishing parameters accordingly, preventing unnecessary polishing cycles and reducing total measurement time.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If real-time thickness monitoring is implemented, then production efficiency is improved, but device complexity increases

Engineering Contradiction:

Improveproduction efficiencyVSAvoidapparatus complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical measurement systems with a simpler sensor-based detection system. Instead of using elaborate mechanical probing or separate measuring equipment, the invention uses electrical or optical sensors integrated into the polishing table or head to detect substrate thickness, simplifying the overall device structure while enabling real-time monitoring.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 faster and more accurate thickness measurement, enhancing production efficiency by allowing for continuous monitoring and adjustment of polishing processes, thereby achieving the desired thickness profile more efficiently.

Implementation Method 1

an eddy current sensor that outputs a signal related to a thickness

Methodology Applied

Scientific EffectEddy current: Eddy Currents

Data Source

PatentUS11833636B2Substrate polishing apparatus, method of creating thickness map, and method of polishing a substrate

Publication Date: 2023.12.05 EBARA CORP

AI summary

To measure thickness in a polishing treatment more efficiently. A substrate polishing apparatus comprises a rotatably configured polishing table provided with a sensor that outputs a signal related to a thickness, a rotatably configured polishing head that faces the polishing table, a substrate being attachable to a face of the polishing head that faces the polishing table, and a controller. The controller acquires a signal from the sensor when the sensor passes over a surface to be polished of the substrate, specifies an orbit of the sensor with respect to the substrate on a basis of a profile of the signal, calculates a thickness of the substrate at each point on the orbit on a basis of the signal, and creates a thickness map on a basis of the calculated thickness at each point on a plurality of orbits of the sensor.