XRD Characterization of Sigma-3 Twin Defects in Semiconductor Wafers

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Solution Overview

Problem

Current methods for detecting sigma=3/{111} twin defects in semiconductor wafers are destructive and limited, failing to provide effective wafer-scale characterization, which is crucial for ensuring the quality of electronic devices.

Innovation Solution

Non-destructive XRD characterization methods that utilize (004) pole-figures to quantify the concentration of sigma=3/{111} twin defects in cubic semiconductor wafers, allowing for real-time feedback and integration into fabrication processes to reduce defect formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transmission electron microscopy (TEM) is used to characterize stacking faults and sigma=3 twins, then nanometer-to-micrometer scale characterization is achieved, but the method is destructive and cannot provide wafer-scale macroscopic characterization

Engineering Contradiction:

Improvecharacterization precisionVSAvoidwafer damage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces destructive mechanical/electrical field methods (TEM) with non-destructive electromagnetic radiation (XRD) to achieve wafer-scale characterization without damaging the semiconductor wafer

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from nanometer-to-micrometer scale characterization (TEM) to wafer-scale macroscopic characterization (XRD), expanding the measurement dimension from microscopic to macroscopic level

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If etch-pit density test is used to measure sigma=3/{111} defects, then defect concentration is measured, but the wafer is damaged or destroyed making it useless after testing

Engineering Contradiction:

Improvedefect measurement capabilityVSAvoidwafer usability after test

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the destructive etch-pit density test with non-destructive XRD methodology, substituting chemical/physical damage-based measurement with electromagnetic radiation-based measurement that preserves wafer integrity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a diffraction pattern copy of the wafer's crystal structure that reveals defect information without physically altering or damaging the original wafer

Inventive Principle:

Principle #26Copying

3Difficulty of detecting and measuring

If known defect measuring techniques are used, then sigma=3/{111} defects can be detected, but the techniques are destructive and limit real-time feedback integration into fabrication processes

Engineering Contradiction:

Improvedefect detection capabilityVSAvoidreal-time feedback capability

Core Design Contradiction:

Difficulty of detecting and measuringVSProductivity

Solution Approach 1:

The patent replaces slow, destructive, batch-processing measurement techniques with rapid, non-destructive XRD that enables real-time or near-real-time feedback integration into continuous fabrication processes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables continuous quality monitoring by replacing intermittent, destructive testing with ongoing non-destructive XRD measurements that can be integrated into the fabrication process flow

Inventive Principle:

Principle #20Continuity of useful action

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 rapid, non-destructive measurement of sigma=3/{111} twin defects, providing a quality factor that ensures wafer quality and identifies defects for process modifications, thereby reducing the number of defective wafers produced.

Implementation Method 1

X-ray diffraction (XRD) characterization methods for sigma=3 twin defects in cubic semiconductor (100) wafers

Methodology Applied

Scientific EffectX-ray diffraction: Bragg Diffraction

Data Source

PatentUS9835570B2X-ray diffraction (XRD) characterization methods for sigma=3 twin defects in cubic semiconductor (100) wafers

Publication Date: 2017.12.05 UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR NAT AERONAUTICS & SPACE ADMINISTRATION

AI summary

An X-ray defraction (XRD) characterization method for sigma=3 twin defects in cubic semiconductor (100) wafers includes a concentration measurement method and a wafer mapping method for any cubic tetrahedral semiconductor wafers including GaAs (100) wafers and Si (100) wafers. The methods use the cubic semiconductor's (004) pole figure in order to detect sigma=3/{111} twin defects. The XRD methods are applicable to any (100) wafers of tetrahedral cubic semiconductors in the diamond structure (Si, Ge, C) and cubic zinc-blend structure (InP, InGaAs, CdTe, ZnSe, and so on) with various growth methods such as Liquid Encapsulated Czochralski (LEC) growth, Molecular Beam Epitaxy (MBE), Organometallic Vapor Phase Epitaxy (OMVPE), Czochralski growth and Metal Organic Chemical Vapor Deposition (MOCVD) growth.