Wafer Pedestal Auto-Calibration for Thermal Offset Correction

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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 calibration wafer, measuring entry and exit offsets, and determining a condition correction using a reference coordinate system to align wafers accurately despite temperature-induced shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If coordinates are programmed into the robot during set-up process when the process module is cold, then the initial wafer placement is accurate, but the coordinates shift when the process module is heated or placed under vacuum, causing misalignment

Engineering Contradiction:

Improvewafer placement accuracyVSAvoidcoordinate stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The system performs preliminary calibration actions by delivering a calibration wafer to the process module, measuring its entry and exit offsets, and calculating the temperature-induced offset before actual wafer processing begins. This preliminary measurement and correction process ensures that subsequent wafer placements remain accurate despite thermal expansion or vacuum conditions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the calibration parameters by measuring offsets at different temperature conditions (cold set-up vs. heated operation). By detecting the entry offset when the process module is cold and the exit offset when heated, the system calculates the temperature-induced offset and uses this information to correct coordinate shifts during operation.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If the process module is heated to higher temperature for processing, then the semiconductor manufacturing process can proceed, but the coordinates of locations within the process module move, causing placement errors

Engineering Contradiction:

Improveprocess temperatureVSAvoidwafer placement precision

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The system implements feedback by measuring the actual exit offset of the calibration wafer after it has been subjected to the temperature-induced offset, comparing this measurement with the expected position, and using the detected discrepancy to calculate and apply a correction factor for subsequent wafer placements during heated operation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The calibration process is performed preliminarily before actual production wafer processing to establish the temperature-induced offset characteristics. This preliminary calibration enables the system to compensate for thermal expansion effects during subsequent high-temperature processing operations.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the process module is placed under vacuum conditions, then semiconductor processing can occur, but coordinate shifts occur leading to misalignment errors

Engineering Contradiction:

Improveprocessing reliabilityVSAvoidlocation coordinate precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system accounts for parameter changes by measuring and calculating offsets under different vacuum conditions. By performing calibration measurements that capture the coordinate shifts induced by vacuum conditions, the system can apply appropriate corrections to maintain placement accuracy during vacuum-based semiconductor processing operations.

Inventive Principle:

Principle #35Parameter changes

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

Reduces misalignment errors in wafer placement, enabling smaller form factors for semiconductor devices and integrated circuits by correcting for temperature-induced offsets in process modules.

Implementation Method 1

determining a temperature induced offset in a pedestal of a process module under a temperature condition for a process

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20260076140A1Auto-calibration to a station of a process module that spins a wafer

Publication Date: 2026.03.12 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.