Via Structure Measurement Using Optical Reflectometry

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for measuring via structures in semiconductor manufacturing, particularly those with high density, high aspect ratio, or small apertures, are slow and destructive, failing to provide non-destructive measurements of depth and bottom profile effectively.

Innovation Solution

A system and method utilizing a reflectometer to collect and compare diffraction spectrums with simulated spectrums, determining via structure parameters such as depth and bottom profile through frequency and magnitude information, employing an ellipsoid model to simulate and analyze diffraction patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electronic microscopes or spring probes are used to measure via structures with high density, high aspect ratio or small aperture, then measurement capability is improved, but measurement speed decreases and the measurement becomes destructive

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidmeasurement speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces mechanical measurement systems (electronic microscopes, spring probes) with an optical measurement system using reflectometry. The system uses optical reflectance signals to measure via structure parameters non-destructively and rapidly, eliminating the speed and destructiveness limitations of mechanical methods while maintaining measurement precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent measures multiple via structure parameters (depth, bottom profile, via diameter, mandrel diameter, mandrel roughness, via liner thickness, via fill material thickness) simultaneously through optical reflectance parameter analysis, improving productivity by obtaining all measurements in a single non-destructive optical scan rather than multiple sequential mechanical measurements

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidstructure damage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical measurement systems with an optical reflectometry system that measures via structures non-destructively. The optical method uses reflected light signals to characterize via parameters without physical contact or damage to the delicate high-density, high-aspect-ratio via structures

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an optical model/representation of the via structure by analyzing reflectance signals and comparing them with simulated diffraction spectrums. This optical copying method allows measurement without direct mechanical interaction that would damage the structure

Inventive Principle:

Principle #26Copying

3Object-affected harmful factors

If optical microscope is used to measure large sized via structures with aperture greater than 10 micrometers, then measurement is non-destructive, but measurement capability for high density or small aperture vias is lost

Engineering Contradiction:

Improvenon-destructive measurementVSAvoidmeasurement capability

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent extends optical measurement capability to small aperture and high-density vias by analyzing specific parameters in the diffraction spectrum (frequency information for depth, magnitude information for bottom profile). This parameter-based analysis enables the optical method to resolve features much smaller than the 10 micrometer limitation of conventional optical microscopy

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

Enables fast and non-destructive measurement of via structure parameters, suitable for high-density and high-aspect-ratio applications, improving measurement accuracy and preventing damage to the structures.

Implementation Method 1

a reflectometer is configured to collect a measured diffraction spectrum of at least a via structure

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS8139233B2System and method for via structure measurement

Publication Date: 2012.03.20 OMNIMEASURE TECH INC

AI summary

A system for via structure measurement is disclosed. The system comprises a reflectometer, a simulation unit and a comparing unit. The reflectometer is configured to collect a measured diffraction spectrum of at least a via. The simulation unit is configured to provide simulated diffraction spectrums of the at least a via. The comparing unit is configured to determine at least a depth and at least a bottom profile of the at least a via by comparing the collected diffraction spectrum and the simulated diffraction spectrums.