Double-Side Polishing Apparatus Real-Time Condition Adjustment

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Solution Overview

Problem

Conventional double-side polishing methods for semiconductor wafers are limited in adjusting polishing conditions in response to changes in the polishing environment during the process, leading to variations in polishing quality and defects in processed wafers.

Innovation Solution

A method that uses multiple regression analysis to determine a criterion function based on shape indices and apparatus log data, allowing for real-time adjustments of polishing conditions such as rotation speed and load to match changing environmental conditions during polishing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional double-side polishing methods are used with predetermined polishing conditions, then the polishing process can be completed, but the polishing quality varies due to changes in the polishing environment during the process

Engineering Contradiction:

Improvepolishing qualityVSAvoidconsistency of polishing quality

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the actual polishing environment parameters (slurry temperature, polishing pad wear degree, local slurry supply amount) are measured during the polishing process, and these measurements are used to adjust the polishing conditions in real-time. This closed-loop control system compensates for environmental changes and maintains consistent polishing quality throughout the process.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent transforms the static predetermined polishing conditions into dynamic adjustable parameters. The polishing conditions (such as rotation speed, load, slurry flow rate) are no longer fixed but are continuously adjusted based on real-time measurements of the polishing environment, allowing the system to adapt to changing conditions during the polishing process.

Inventive Principle:

Principle #15Dynamics

2Reliability

If polishing conditions are adjusted in response to changing environment during polishing, then polishing quality consistency improves, but the system complexity increases

Engineering Contradiction:

Improveconsistency of polishing qualityVSAvoidpolishing control system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces intermediary sensing devices and control elements that mediate between the polishing environment and the polishing parameters. These intermediaries (sensors for measuring temperature, wear, and slurry supply; actuators for adjusting rotation speed and load) enable automatic real-time adjustments without requiring complex direct control mechanisms, thereby managing system complexity while maintaining reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If multiple measurement and adjustment steps are added during polishing, then polishing quality control improves, but the polishing time increases

Engineering Contradiction:

Improvepolishing quality controlVSAvoidpolishing cycle time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs measurements and adjustments continuously during the polishing process rather than interrupting the polishing to perform discrete measurement and adjustment cycles. The sensing and control operations are integrated into the continuous polishing flow, allowing quality control without significant time loss and maintaining the continuity of the useful polishing action.

Inventive Principle:

Principle #20Continuity of useful action

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 approach significantly reduces variation in polishing quality by dynamically adjusting polishing parameters, improving the yield of semiconductor wafers to meet target shapes and reducing defects.

Implementation Method 1

chemical mechanical polishing by applying pressure using the polishing pads 60a and 60b

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

chemical mechanical polishing by applying pressure using the polishing pads 60a and 60b and applying slurry

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 3

chemical mechanical polishing by applying pressure using the polishing pads 60a and 60b and applying slurry

Methodology Applied

Scientific EffectChemical mechanical polishing:

Data Source

PatentUS11731234B2Method of double-side polishing semiconductor wafer

Publication Date: 2023.08.22 SUMCO CORP

AI summary

Provided is a method of double-side polishing a semiconductor wafer, which can suppress variation in the polishing quality by providing for changes in the polishing environment during polishing. The method of double-side polishing of a semiconductor wafer includes: a step of predetermining a criterion function for determining polishing tendencies of double-side polishing; a first step of starting double-side polishing of the semiconductor wafer under initial polishing conditions; a second step of while performing double-side polishing on the semiconductor wafer under the initial polishing conditions, calculating a value of the criterion function using the apparatus log data in a predetermined period of polishing in the first step, and setting on the double-side polishing apparatus polishing conditions obtained by adjusting the initial polishing conditions based on the value of the criterion function; and a third step of performing double-side polishing of the semiconductor wafer under the adjusted polishing conditions.