Polishing Pad Shape Modification via Automated Optical Measurement

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Solution Overview

Problem

Conventional chemical mechanical polishing (CMP) methods face challenges in achieving stable and accurate planarization of wafers due to polishing pad surface flatness deterioration and variations caused by apparatus differences, leading to inefficient manual measurement and adjustment processes.

Innovation Solution

A method for modifying the polishing pad shape using a polishing pad shape measuring apparatus and selective dressing tools to achieve a target shape, determining the most suitable dressing tool and conditions such as dressing time and pressing force to ensure a desired wafer surface shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual measurement and adjustment of polishing pad flatness is performed, then the polishing pad can be dressed, but it requires a great amount of time and is inefficient

Engineering Contradiction:

Improvedressing efficiencyVSAvoidmeasuring operation time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical measurement operations with an automated optical measurement system. A laser displacement meter and sensor automatically measure the polishing pad surface shape, eliminating the need for manual measurement tools and operations, thereby dramatically reducing measurement time and increasing dressing efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-service by automatically measuring the polishing pad surface shape and calculating the optimal dressing amount without human intervention. The measurement and calculation processes are performed autonomously by the measurement unit and control unit, freeing operators from time-consuming manual measurement tasks.

Inventive Principle:

Principle #25Self-service

2Manufacturing precision

If the polishing pad is dressed to improve flatness, then the surface shape changes, but the flatness deteriorates due to cumulative polishing

Engineering Contradiction:

Improvewafer planarization accuracyVSAvoidpolishing pad flatness stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback control system where the polishing pad surface shape is continuously measured before and after dressing operations. The measurement data is used to calculate the optimal dressing amount, and the process is repeated until the target surface shape is achieved, ensuring stable and accurate wafer planarization despite cumulative polishing effects.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary measurement of the polishing pad surface shape before dressing to determine the optimal dressing amount. This preliminary action allows the system to compensate for future flatness deterioration by adjusting the dressing parameters in advance, maintaining stable flatness over time.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If a polishing pad is used for multiple wafers, then productivity increases, but the polishing amount decreases due to surface clogging

Engineering Contradiction:

Improvewafer polishing throughputVSAvoidpolishing amount consistency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements continuous monitoring of the polishing pad surface shape during use. By continuously measuring the pad profile and comparing it against target values, the system maintains the polishing pad in an optimal state throughout its service life, ensuring consistent polishing performance across multiple wafers without premature replacement.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system replaces manual inspection and judgment of polishing pad condition with automated optical measurement. The laser displacement meter continuously and objectively measures the pad surface shape, providing reliable data on polishing performance degradation and enabling precise determination of when dressing or replacement is needed, maintaining reliability throughout extended use.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2345505B1Method for dressing a polishing pad

Publication Date: 2018.03.21 SUMCO CORP

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AI summary

A polishing pad (14) shape measured by a polishing pad shape measuring apparatus (14) is modified into a target shape of a polishing pad (14) by using a dressing tool so that a wafer has a desired surface shape. The invention is a method for shape modification of a polishing pad (14) for polishing a workpiece into a desired surface shape, comprising: a measurement step (S9) of measuring a polishing pad (14) shape in a state of being attached to a plate (12) by using a polishing pad shape measuring apparatus (10); a condition determination step (S10) of selecting a dressing recipe capable of polishing the polishing pad (14) into a desired surface shape from a plurality of pre-provided dressing recipes based on the measurement result in the measurement step (S9); and a shape modification step (S11) of dressing the polishing pad (14) by using the dressing recipe determined in the condition determination step (S10).