Semiconductor Overlay Alignment Compensation via Pre-Measurement

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Solution Overview

Problem

The increasing complexity of semiconductor manufacturing due to smaller critical dimensions poses challenges in achieving accurate alignment and overlay precision, as existing methods are not sufficient to ensure the required alignment accuracy for advanced lithography technologies, leading to inefficiencies and higher costs.

Innovation Solution

The implementation of a method that uses a combination of coarse and fine alignment marks, along with overlay measurement marks, and a virtual alignment and pre-overlay measurement tool to improve alignment accuracy by determining compensation data for subsequent alignment operations, reducing overlay errors and enhancing manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If advanced lithography technologies are used to scale down geometry size, then production efficiency increases and costs decrease, but overlay errors increase and alignment accuracy deteriorates

Engineering Contradiction:

Improveproduction efficiencyVSAvoidalignment accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent performs pre-overlay measurement and determines compensation data before the actual lithography exposure process. By measuring overlay errors in advance using alignment marks and calculating compensation values, the system prepares correction parameters that will be applied during subsequent alignment operations, preventing overlay errors rather than correcting them after the fact.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where overlay measurement marks are used to detect actual overlay errors, this information is fed back to calculate compensation data, and the compensation data is then applied to adjust alignment parameters in subsequent lithography processes, creating a closed-loop system that continuously improves alignment accuracy.

Inventive Principle:

Principle #23Feedback

2Device complexity

If traditional alignment methods are used, then the manufacturing process is simpler, but alignment accuracy cannot achieve 3-5 nm or less

Engineering Contradiction:

Improvemanufacturing process complexityVSAvoidalignment accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the alignment system into multiple functional components: alignment marks embedded in the substrate, overlay measurement marks for detecting errors, a virtual alignment tool for pre-measurement, and compensation data calculation. This segmentation allows each component to be optimized independently while working together to achieve ultra-precise alignment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces overlay measurement marks as intermediary elements between the alignment marks and the lithography process. These measurement marks serve as mediators that enable precise detection of overlay errors without interfering with the actual product patterns, allowing accurate measurement and compensation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If multiple alignment marks and measurement marks are used, then alignment accuracy improves, but the number of components and process steps increases

Engineering Contradiction:

Improvealignment accuracyVSAvoidnumber of components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent designs alignment marks and overlay measurement marks that serve multiple functions: alignment marks are used both for initial alignment and as reference points for overlay measurement, while overlay measurement marks simultaneously enable error detection and compensation verification. This multi-functionality reduces the need for separate dedicated components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the alignment mark structure with overlay measurement capabilities by integrating measurement features directly into the alignment mark design. This merging allows the same physical structures to perform both alignment and measurement functions, reducing component count while maintaining precision.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11392045B2Method for manufacturing semiconductor device and system for performing the same

Publication Date: 2022.07.19 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for manufacturing a structure on a substrate includes projecting an image of a reference pattern onto a substrate having a first patterned layer, the first patterned layer including first alignment marks and first overlay measurement marks, and the reference pattern including second alignment marks and second overlay measurement marks, aligning, based on the first alignment marks and the second alignment marks, the first patterned layer to the image of the reference pattern, obtaining a pre-overlay mapping of the first overlay measurement marks and the second overlay measurement marks, and determining compensation data indicative of information of the pre-overlay mapping of the first overlay measurement marks and the second overlay measurement marks.