Wafer Spin Module Calibration Under Thermal and Vacuum Offset

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Solution Overview

Problem

Existing semiconductor processing systems face challenges in accurately placing wafers during process conditions due to coordinate shifts in process modules under vacuum or elevated temperatures, leading to misalignment and increased errors in semiconductor device fabrication.

Innovation Solution

A method for calibrating the offset of a rotation axis within a process module by delivering a wafer, detecting entry and exit offsets, and determining the magnitude and direction of temperature-induced offsets using a reference coordinate system and measurement devices outside the process module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If coordinates are programmed into the robot during set-up process when the process module is cold, then the set-up process is simple and can be performed by technician, but the coordinates shift when the process module is under vacuum or elevated temperature causing misalignment

Engineering Contradiction:

Improveset-up process simplicityVSAvoidwafer placement accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing calibration measurements before actual wafer processing. A calibration wafer is used to measure the pedestal center position under process conditions (vacuum and elevated temperature) before real wafers are processed. This preliminary calibration allows the system to determine coordinate offsets and compensate for thermal expansion effects, ensuring accurate wafer placement during subsequent processing operations.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the process module is placed under vacuum or elevated temperature for processing, then semiconductor devices can be fabricated, but the coordinates of locations within the process module move causing misalignment errors

Engineering Contradiction:

Improvesemiconductor device fabricationVSAvoidwafer placement accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by measuring the pedestal center position under actual process conditions (vacuum and elevated temperature) rather than at ambient conditions. The system varies the operational parameters (temperature, vacuum) to match production conditions and performs calibration measurements at these changed parameters. This allows the system to account for thermal expansion and vacuum-induced dimensional changes, maintaining manufacturing precision during semiconductor device fabrication.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces manual mechanical set-up procedures with an automated optical measurement system. Instead of relying on technicians to manually program coordinates based on cold-module measurements, the system uses an automated vision system or laser interferometer to measure the actual pedestal center position under process conditions. This substitution of mechanical set-up with optical/electronic measurement eliminates the coordinate shift problem caused by thermal expansion and vacuum effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If manual set-up process is used to program coordinates, then device complexity is low, but measurement precision of pedestal center under process conditions is insufficient

Engineering Contradiction:

Improvecalibration system complexityVSAvoidpedestal center position accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a calibration wafer as an intermediary object to facilitate precise measurement of the pedestal center position. The calibration wafer features precisely manufactured reference marks or alignment features that serve as intermediaries between the measurement system and the pedestal center. This intermediary allows the automated vision system or laser interferometer to accurately determine the pedestal center coordinates under process conditions without requiring direct measurement of the pedestal itself, thereby achieving high measurement precision while keeping the overall system relatively simple.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces misalignment errors by correcting the rotation axis offset, enabling precise wafer placement and improving the form factor of semiconductor devices and integrated circuits.

Implementation Method 1

detecting an entry offset... measuring an exit offset

Methodology Applied

Scientific EffectOptical measurement: Optical Tweezers

Implementation Method 2

temperature induced offset... when the process module is under a temperature condition for a process

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12489006B2Auto-calibration to a station of a process module that spins a wafer

Publication Date: 2025.12.02 LAM RES CORP

AI summary

A method for calibration including determining a temperature induced offset in a pedestal of a process module under a temperature condition for a process. The method includes delivering a wafer to the pedestal of the process module by a robot, and detecting an entry offset. The method includes rotating the wafer over the pedestal by an angle. The method includes removing the wafer from the pedestal by the robot and measuring an exit offset. The method includes determining a magnitude and direction of the temperature induced offset using the entry offset and exit offset.