Electrical approach to Nondestructive Analysis on WB-PBGA with TDR Technology

Time Domain Reflectometry (TDR) is a powerful measurement technique that uses the reflection of a pulse sent down a transmission line to characterize the impedance of that line. The voltage of a reflection will vary depending on the distance to the fault and on the amount of energy reflected. In this paper we develop a simple and effective electrical nondestructive analysis (NA) system for the evaluation of the interconnection of wire-bonded plastic ball grid array (WB-PBGA) package. An open-end fixture (OEF) was employed to connect fast rising edge signals to the package which was monitored for its time delay and reflection voltage parameters. This technology represents a valuable new method for the NA of WB-PBGA packages, and it has enabled the rapid and efficient detection and location of faults. Comparative TDR measurements accurately predicted the location of opens and short circuits in the copper traces of the substrate, bond wire, and solders balls. The TDR analysis was verified by using X-ray analysis. The paper establishes the use of a TDR system incorporating an open-end fixture for locating opens and shorts in WB-PBGA packages.

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Backside Application of Acoustic Micro Imaging (AMI) on Plastic Ball Grid Array (PBGA) and Plastic Quad Flat Pack (PQFP) Packages

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

10.31399/asm.cp.istfa2004p0389 ◽

2004 ◽

Author(s):

Luis A. Curiel ◽

Andrew J. Komrowski ◽

Daniel J.D. Sullivan

Keyword(s):

Ball Grid Array ◽

Acoustic Microscopy ◽

Electronic Packages ◽

Nondestructive Technique ◽

Molding Compound ◽

Microscopy Technique ◽

Plastic Ball ◽

Die Surface ◽

Plastic Ball Grid Array ◽

Bond Pads

Abstract Acoustic Micro Imaging (AMI) is an established nondestructive technique for evaluation of electronic packages. Non-destructive evaluation of electronic packages is often a critical first step in the Failure Analysis (FA) process of semiconductor devices [1]. The molding compound to die surface interface of the Plastic Ball Grid Array (PBGA) and Plastic Quad Flat Pack (PQFP) packages is an important interface to acquire for the FA process. Occasionally, with these packages, the standard acoustic microscopy technique fails to identify defects at the molding compound to die surface interface. The hard to identify defects are found at the edge of the die next to the bond pads or under the bonds wires. This paper will present a technique, Backside Acoustic Micro Imaging (BAMI) analysis, which can better resolve the molding compound to die surface interface at the die edge by sending the acoustic signal through the backside of the PBGA and PQFP packages.

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The Effect of Ball Pad Metallurgy and Ball Composition on Solder Ball Integrity of Plastic Ball Grid Array Packages

ISTFA 1998: Conference Proceedings from the 24th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa1998p0405 ◽

1998 ◽

Author(s):

C.H. Zhong ◽

Sung Yi

Keyword(s):

Failure Mode ◽

Barrier Layer ◽

Shear Force ◽

Solder Ball ◽

Ball Grid Array ◽

Reliability Test ◽

Shear Forces ◽

Ball Shear ◽

Plastic Ball ◽

Plastic Ball Grid Array

Abstract Ball shear forces of plastic ball grid array (PBGA) packages are found to decrease after reliability test. Packages with different ball pad metallurgy form different intermetallic compounds (IMC) thus ball shear forces and failure modes are different. The characteristic and dynamic process of IMC formed are decided by ball pad metallurgy which includes Ni barrier layer and Au layer thickness. Solder ball composition also affects IMC formation dynamic process. There is basically no difference in ball shear force and failure mode for packages with different under ball pad metallurgy before reliability test. However shear force decreased and failure mode changed after reliability test, especially when packages exposed to high temperature. Major difference in ball shear force and failure mode was found for ball pad metallurgy of Ni barrier layer including Ni-P, pure Ni and Ni-Co. Solder ball composition was found to affect the IMC formation rate.

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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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