Hybrid Metrology for Semiconductor Layer Characterization

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Solution Overview

Problem

Current metrology techniques for nanosheet and nanowire technology are inadequate for accurately measuring the thickness of each layer, Germanium concentration in Silicon Germanium layers, strain in Silicon and Silicon Germanium layers, and dielectric properties of Nitride layers, often requiring multiple techniques and sacrificing accuracy or throughput.

Innovation Solution

The equation-based hybridization technique uses the raw signal from a first tool, such as an X-ray tool, as a constraint for a second tool, like an optical scatterometer, to improve measurement accuracy without reducing throughput, by employing raw signal data as a boundary condition for calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single metrology technique is used, then throughput is maintained, but measurement accuracy and precision are insufficient for multiple parameters

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidthroughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent combines data from multiple metrology tools (scatterometry tool and spectroscopic ellipsometry tool) into a unified hybridization model. The scatterometry raw signal serves as a constraint for the ellipsometry calculation, merging the strengths of both techniques to achieve accurate multi-parameter measurement without requiring sequential measurement of each parameter separately, thereby maintaining high throughput while improving measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If multiple metrology techniques are used sequentially, then measurement accuracy improves, but throughput decreases due to extended measurement time

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary action by obtaining the scatterometry raw signal first and using it as a pre-determined constraint for the subsequent ellipsometry calculation. This preliminary use of the first measurement tool's data eliminates the need for iterative adjustments and reduces the time required for the second measurement tool, thereby reducing total measurement time while maintaining the accuracy benefits of using multiple techniques.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If traditional hybridization methods are used, then some measurement parameters are obtained, but the goodness of fit and overall accuracy are insufficient

Engineering Contradiction:
Improvegoodness of fitVSAvoidhybridization complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback by using the scatterometry raw signal as a constraint that feeds into the ellipsometry calculation model. This feedback mechanism ensures that the hybridization model consistently converges to accurate solutions with high goodness of fit (0.99 or better). The feedback loop validates the model parameters against the actual measured signal, improving accuracy while the automated computational process manages the complexity of the hybridization approach.

Inventive Principle:
Principle #23Feedback

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

This approach enhances measurement accuracy and throughput, providing precise results for critical parameters in next-generation device architectures, with a goodness of fit of 0.99, effectively addressing the limitations of traditional hybridization methods.

Implementation Method 1

receiving, using a processor, a raw signal from a first tool representing a measured parameter of a semiconductor device

Methodology Applied
Scientific EffectX-ray scattering: Scattering

Implementation Method 2

receiving, using a processor, a raw signal from a first tool representing a measured parameter of a semiconductor device

Methodology Applied
Scientific EffectX-ray absorption: Absorption (EM radiation)

Implementation Method 3

receiving, using the processor, data on the measured parameter from a second tool

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentUS11295969B2Hybridization for characterization and metrology
Publication Date: 2022.04.05 NOVA MEASURING INSTR LTD
  • US11295969B2 patent drawing
  • US11295969B2 patent drawing
  • US11295969B2 patent drawing

AI summary

A computer-implemented method for measuring a parameter of a semiconductor. A non-limiting example of the computer-implemented method includes receiving, using a processor, a raw signal from a first tool representing a measured parameter of a semiconductor device. The method also receives, using the processor, data on the measured parameter from a second tool, and calculates, using the processor, the measured parameter based on the data received from the second tool and on a constraint based on the raw signal from the first tool.