Silicon Crystal F/G Ratio Control via Automated Feedback

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Solution Overview

Problem

Existing manufacturing systems for silicon single crystals face challenges in consistently achieving desired crystal quality and high yield, particularly in maintaining the N region across the entire length of the crystal, due to variations in pulling rate and temperature gradient, which are influenced by changes in pulling apparatus constituents and manufacturing processes.

Innovation Solution

A system that automates the design of manufacturing conditions by predicting and calculating correction factors for the pulling rate and temperature gradient based on previous batch results, incorporating changes in pulling apparatus constituents and manufacturing processes, to ensure the F/G ratio falls within a predetermined range, thereby ensuring consistent crystal quality and high yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual design of manufacturing conditions is used based on previous batch results, then operational flexibility is maintained, but manufacturing precision and consistency of crystal quality deteriorate due to human error and inability to account for all variable changes

Engineering Contradiction:
Improvecrystal quality controlVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system implements automatic feedback by using actual crystal quality results from previous batches to adjust and optimize manufacturing conditions for subsequent batches. The computer automatically calculates corrected pulling rates and temperature gradients based on measured deviations, creating a closed-loop control system that continuously improves crystal quality without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical calculation and adjustment processes with an automated computer-based system. The computer calculates optimal manufacturing parameters by processing previous batch data and applying correction algorithms, substituting human operators with an automated computational system that eliminates human error and increases precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If complex manual calculations and adjustments are performed to account for apparatus changes and process variations, then manufacturing precision improves, but loss of time and operational complexity increase

Engineering Contradiction:
ImproveF/G ratio controlVSAvoidcondition design time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system enables self-service automation where the computer automatically performs all calculations and adjustments without requiring manual intervention. The system takes previous batch results and apparatus change information as inputs, automatically computes corrected manufacturing conditions, and outputs optimized parameters, making the complex adjustment process autonomous and eliminating time-consuming manual operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent automatically adjusts critical parameters such as pulling rate and temperature gradient based on measured deviations in F/G ratio. The computer calculates specific parameter corrections needed to compensate for apparatus changes and process variations, dynamically modifying manufacturing parameters to maintain optimal crystal growth conditions without manual calculation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If fixed manufacturing conditions are used across batches, then operational simplicity is maintained, but manufacturing precision deteriorates due to unaccounted variations in apparatus constituents and processes

Engineering Contradiction:
Improveoperational simplicityVSAvoidcrystal quality consistency
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The system maintains ease of operation by requiring minimal user input while automatically implementing feedback loops. The computer continuously monitors crystal quality results and apparatus status, automatically adjusting manufacturing conditions based on measured deviations. This feedback mechanism ensures consistent crystal quality while maintaining operational simplicity, as the system handles all complex adjustments autonomously.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex manual adjustment mechanisms with an automated computer system that handles all condition optimization. The computer substitutes manual calculation and adjustment processes, automatically computing corrected pulling rates and temperature gradients based on previous batch performance and current apparatus status, thereby maintaining both simplicity and precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If automated systems are implemented to control manufacturing conditions, then productivity and consistency improve, but device complexity and initial investment increase

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidsystem structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The computer system performs multiple functions within a single integrated platform: it stores apparatus constituent information, processes crystal quality measurement data, calculates optimal manufacturing parameters, and controls pulling apparatus operations. This multi-functional approach consolidates what would otherwise require separate systems, reducing overall complexity while maintaining high productivity and consistency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The automated system operates autonomously by automatically collecting data from sensors, calculating optimal parameters, and adjusting manufacturing conditions without continuous human intervention. This self-service capability eliminates the need for complex manual monitoring and adjustment mechanisms, achieving high productivity through streamlined automation rather than complex multi-component systems.

Inventive Principle:
Principle #25Self-service

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 allows for highly accurate control of crystal quality, reducing operational burdens and improving efficiency, enabling the production of silicon single crystals with desired properties and high productivity, even in cases where the N region is difficult to maintain across the entire crystal length.

Implementation Method 1

a temperature gradient G of a solid-liquid interface along an axis direction in a crystal

Methodology Applied
Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 2

manufacturing conditions under which a value of a ratio F/G between a pulling rate F and a temperature gradient G of a crystal solid-liquid interface along an axis direction is controlled to fall within a predetermined range in order that a crystal quality of a silicon single crystal manufactured by a pulling apparatus using the Czochralski method

Methodology Applied
Scientific EffectCzochralski method: Crystallisation

Data Source

PatentEP2039811B1System for manufacturing silicon single crystal and method for manufacturing silicon single crystal using this system
Publication Date: 2012.09.19 SHIN ETSU HANDOTAI CO LTD
  • EP2039811B1 patent drawingFigure 1
  • EP2039811B1 patent drawingFigure 2
  • EP2039811B1 patent drawingFigure 3

AI summary

The present invention provides a system for manufacturing a silicon single crystal which designs manufacturing conditions under which a value of F/G is controlled to fall within a predetermined range in order that a crystal quality of a silicon single crystal manufactured by a pulling apparatus using the CZ method falls within a target standard, including, automatically, at least: means 1 tentatively designing manufacturing conditions of a silicon single crystal in a subsequent batch from a crystal quality result of a silicon single crystal in a previous batch; means 2 calculating a correction amount from an amount of change in F and/or G due to constituent members of the pulling apparatus in the subsequent batch; means 3 calculating a correction amount from an amount of change in F and/or G due to a manufacturing process in the subsequent batch; and means 4 adding the correction amount by the means 2 and/or the means 3 to the manufacturing conditions by the means 1 to calculate manufacturing conditions in the subsequent batch. As a result, there can be provided the system for manufacturing a silicon single crystal that can more assuredly obtain a silicon single crystal having a desired crystal quality and improve productivity or a yield and a method for manufacturing a silicon single crystal using this system.