Non-destructive measurement of stem water content by time domain reflectometry using short probes

The measurement of moisture distribution in Engineered Barrier Systems (EBS) in salt mines and deep geological disposals is essential in order to monitor fluid ingress and record data for long-term security analyses. Additionally, soil moisture content has influence over the mechanical properties of the soil as well as plant growth, soil stability and contaminant transport to cite some. Therefore, finding affordable and reliable ways to determine moisture content, quickly and in the field without sampling, is of great interested among people in different subject areas. Time-domain reflectometry (TDR) has become a recognized electromagnetic method for non-destructive measurement of dielectric permittivity and electrical conductivity of moist porous materials. It turns out that both these measurements depend on the material moisture content, among other things. This paper presents a series of calibration tests performed on soil samples. TDR probes were used to obtain the dielectric permittivity and electrical conductivity of the samples. As a consequence, relationships between these measurements and the samples' volumetric water content were later established. These relationships can then be used to indirectly determine that important information of water content on similar soil material using cheap, quick and non-destructive TDR probes.

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Advanced Non-Destructive Fault Isolation Techniques for PCB Substrates Using Magnetic Current Imaging and Terahertz Time Domain Reflectometry

10.31399/asm.cp.istfa2018p0043 ◽

2018 ◽

Author(s):

Daechul Choi ◽

Yoonseong Kim ◽

Jongyun Kim ◽

Han Kim

Keyword(s):

Time Domain ◽

Quantum Interference ◽

Flip Chip ◽

Imaging System ◽

Time Domain Reflectometry ◽

Fault Isolation ◽

Magnetic Current ◽

Isolation Techniques ◽

Super Conducting ◽

Non Destructive

Abstract In this paper, we demonstrate cases for actual short and open failures in FCB (Flip Chip Bonding) substrates by using novel non-destructive techniques, known as SSM (Scanning Super-conducting Quantum Interference Device Microscopy) and Terahertz TDR (Time Domain Reflectometry) which is able to pinpoint failure locations. In addition, the defect location and accuracy is verified by a NIR (Near Infra-red) imaging system which is also one of the commonly used non-destructive failure analysis tools, and good agreement was made.

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Time Domain Reflectometry Technique for Failure Analysis

ISTFA 2004: Conference Proceedings from the 30th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2004p0616 ◽

2004 ◽

Author(s):

Teoh King Long ◽

Ko Yin Fern

Keyword(s):

Failure Analysis ◽

Time Domain ◽

Time Domain Reflectometry ◽

Fault Isolation ◽

Reference Plane ◽

First Case ◽

Main Emphasis ◽

Plastic Ball ◽

Solder Balls ◽

Non Destructive

Abstract In time domain reflectometry (TDR), the main emphasis lies on the reflected waveform. Poor probing contact is one of the common problems in getting an accurate waveform. TDR probe normalization is essential before measuring any TDR waveforms. The advantages of normalization include removal of test setup errors in the original test pulse and the establishment of a measurement reference plane. This article presents two case histories. The first case is about a Plastic Ball Grid Array package consisting of 352 solder balls where the open failure mode was encountered at various terminals after reliability assessment. In the second, a three-digit display LED suspected of an electrical short failure was analyzed using TDR as a fault isolation tool. TDR has been successfully used to perform non-destructive fault isolation in assisting the routine failure analysis of open and short failure. It is shown to be accurate and reduces the time needed to identify fault locations.

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Advanced Fault Isolation Technique Using Electro-Optical Terahertz Pulse Reflectometry (EOTPR) for 2D and 2.5D Flip-Chip Package

ISTFA 2012: Conference Proceedings from the 38th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2012p0021 ◽

2012 ◽

Author(s):

Lihong Cao ◽

Manasa Venkata ◽

Meng Yeow Tay ◽

Wen Qiu ◽

J. Alton ◽

...

Keyword(s):

Time Domain ◽

Flip Chip ◽

Time Domain Reflectometry ◽

Fault Isolation ◽

Experimental Results ◽

Terahertz Pulse ◽

Isolation And Identification ◽

Isolation Technique ◽

Non Destructive

Abstract Electro-optical terahertz pulse reflectometry (EOTPR) was introduced last year to isolate faults in advanced IC packages. The EOTPR system provides 10μm accuracy that can be used to non-destructively localize a package-level failure. In this paper, an EOTPR system is used for non-destructive fault isolation and identification for both 2D and 2.5D with TSV structure of flip-chip packages. The experimental results demonstrate higher accuracy of the EOTPR system in determining the distance to defect compared to the traditional time-domain reflectometry (TDR) systems.

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