Wafer Overlay Feedforward Correction for EUV Table Degradation

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Solution Overview

Problem

As semiconductor circuits become finer, overlay errors due to wafer table degradation occur in EUV exposure processes, which are not effectively addressed by existing technologies.

Innovation Solution

An overlay correction method that involves acquiring leveling data, converting it into overlay data, splitting shots into sub-shots, extracting models for each sub-shot, and correcting overlay parameters in real time using a feedforward method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If existing overlay correction methods are used, then general overlay errors can be addressed, but overlay errors due to wafer table degradation cannot be effectively corrected

Engineering Contradiction:

Improveoverlay accuracyVSAvoideffectiveness against wafer table degradation

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent divides the wafer surface into multiple regions and acquires leveling data for each region separately. This segmentation allows the system to capture local variations in wafer table degradation across different areas of the wafer, enabling more precise correction of overlay errors caused by table degradation rather than treating the entire wafer surface uniformly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs feedforward correction by acquiring leveling data and calculating overlay correction values before the actual exposure process. This preliminary action allows the system to pre-compensate for wafer table degradation effects, ensuring accurate overlay from the start rather than attempting correction after errors have occurred during exposure.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If real-time correction is implemented, then overlay accuracy improves, but processing time increases

Engineering Contradiction:

Improveoverlay correction accuracyVSAvoidcorrection processing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs overlay correction calculations in advance before the exposure process begins. By acquiring leveling data and computing correction values beforehand, the system eliminates the need for time-consuming real-time calculations during exposure, thus improving overlay accuracy without adding processing time delays.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex real-time mechanical adjustment systems with a computational approach using leveling data and feedforward correction algorithms. This substitution allows overlay correction to be performed efficiently through data processing rather than requiring complex real-time mechanical interventions during the exposure process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12585199B2Overlay correction method, and exposure method and semiconductor device manufacturing method including overlay correction method

Publication Date: 2026.03.24 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided are an overlay correction method for effectively correcting an overlay due to degradation of a wafer table, and an exposure method and a semiconductor device manufacturing method, which include the overlay correction method, wherein the overlay correction method includes acquiring leveling data regarding a wafer, converting the leveling data into overlay data, splitting a shot into sub-shots via shot size split, extracting a model for each sub-shot from the overlay data, and correcting an overlay parameter of exposure equipment on the basis of the model for each sub-shot, wherein the correction of the overlay parameter is applied in real time to an exposure process for the wafer in a feedforward method.