Wafer Inspection Device Aligning Feature Points via Reference Coordinates

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Solution Overview

Problem

In the photolithography process, the alignment of wafer images is critical for defect detection, but image sensors may shake during scanning, leading to non-uniform patterns and inaccurate defect identification due to varying feature point coordinates across different image sets.

Innovation Solution

An inspection device comprising multiple processors and a server that detects feature points from multiple image sets, generates reference coordinates, and aligns images based on these coordinates to compensate for sensor shaking, ensuring accurate alignment and defect detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple image sets are scanned across different swaths on a wafer, then the coverage area increases, but image alignment accuracy deteriorates due to sensor shaking during scanning

Engineering Contradiction:

Improveinspection coverage areaVSAvoidimage alignment accuracy

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent introduces reference coordinates as an intermediary element that mediates between multiple image sets captured during scanning. These reference coordinates serve as a common reference framework that allows images from different swaths to be aligned accurately despite sensor shaking, thus resolving the contradiction between increased coverage area and maintained alignment precision

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the alignment problem by changing the parameter space from direct coordinate comparison to reference coordinate-based alignment. By detecting feature points and mapping them to reference coordinates, the system enables accurate alignment across multiple swaths while maintaining large inspection coverage, effectively resolving the precision-coverage tradeoff

Inventive Principle:

Principle #35Parameter changes

2Productivity

If feature point coordinates are used directly for defect detection, then the detection process is simple, but false positives increase due to non-uniform patterns from sensor shaking

Engineering Contradiction:

Improvedefect detection speedVSAvoiddefect detection accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-establishing reference coordinates and aligning all image sets to this reference framework before defect detection. This preliminary alignment step ensures that feature points from different swaths are in consistent positions, eliminating false positives caused by sensor shaking while maintaining efficient defect detection throughput

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10474133B2Inspection device for inspecting wafer and method of inspecting wafer using the same

Publication Date: 2019.11.12 SAMSUNG ELECTRONICS CO LTD

AI summary

An inspection device includes a first processor, a second processor, and a server. The first processor detects first coordinates of first feature points from first images in a first image set. The second processor detects second coordinates of second feature points from second images in a second image set. The server generates reference coordinates based on the first coordinates and the second coordinates. The reference coordinates are transmitted to the first processor and the second processor. The first and second image sets correspond to scanned swaths on a wafer.