scholarly journals Root Cause Analysis of a Printed Circuit Board (PCB) Failure in a Public Transport Communication System

2022 ◽  
Vol 12 (2) ◽  
pp. 640
Author(s):  
Cher-Ming Tan ◽  
Hsiao-Hi Chen ◽  
Jing-Ping Wu ◽  
Vivek Sangwan ◽  
Kun-Yen Tsai ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Essential Element ◽  
Circuit Board ◽  
Cause Analysis ◽  
Printed Circuit ◽  
Root Cause ◽  
Burn Out ◽  
Root Cause Identification

A printed circuit board (PCB) is an essential element for practical circuit applications and its failure can inflict large financial costs and even safety concerns, especially if the PCB failure occurs prematurely and unexpectedly. Understanding the failure modes and even the failure mechanisms of a PCB failure are not sufficient to ensure the same failure will not occur again in subsequent operations with different batches of PCBs. The identification of the root cause is crucial to prevent the reoccurrence of the same failure. In this work, a step-by-step approach from customer returned and inventory reproduced boards to the root cause identification is described for an actual industry case where the failure is a PCB burn-out. The failure mechanism is found to be a conductive anodic filament (CAF) even though the PCB is CAF-resistant. The root cause is due to PCB de-penalization. A reliability verification to assure the effectiveness of the corrective action according to the identified root cause is shown to complete the case study. This work shows that a CAF-resistant PCB does not necessarily guarantee no CAF and PCB processes can render its CAF resistance ineffective.

Temperature and Humidity Dependent Reliability Analysis of RGB LED Chips

2006 ◽  
Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris
Keyword(s):  
Reliability Analysis ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Light Emitting ◽  
Printed Circuit ◽  
Root Cause ◽  
Micro Cracks ◽  
Temperature And Humidity

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.

Unique Failure Modes from use of Sn-Pb and Lead-Free (mixed metallurgies) in PCB Assembly: Case Study

2005 ◽  
Author(s):  
Frank Toth ◽  
Gary F. Shade
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Circuit Board ◽  
Lead Free ◽  
Printed Circuit ◽  
Pcb Assembly ◽  
New Process ◽  
Solder Pastes

Abstract Printed Circuit Board (PCB) assemblies are moving toward lead-free (LF) alloys and away from the traditional Sn-Pb alloy [1]. This change is creating new and unique failure modes as the process adapts to accommodate the higher temperatures of the new process [2]. In addition, mis-processed lots are more likely due to the complexity of assembling a mix of Sn-Pb and leadfree solders, components, PCBs, solder pastes, and fluxes. This case study helps to highlight the challenge and provides an example of what can happen, how to detect it, and how the defects can cause reliability failures.

Case Study—Failure Analysis of a Printed Circuit Board Latent Failure and Resulting Implication of Weaknesses in Panel Coupons and Lot DPA

2017 ◽  
Author(s):  
Tom Tuite
Keyword(s):  
Failure Mechanism ◽  
Printed Circuit Board ◽  
Short Circuit ◽  
Circuit Board ◽  
System Level ◽  
Drilling Process ◽  
Printed Circuit ◽  
Root Cause ◽  
Ionic Contamination ◽  
Root Cause Identification

Abstract Multiple, independent, system level test failures that occurred around the same time were traced back to a short circuit on the same type of printed circuit board (PCB). The PCBs were removed from the application and sent to the authors' lab for analysis. This paper reviews the analysis techniques and results that led to the failure mechanism being identified. The discussion focuses on steps taken to exonerate the authors' lab and processes as possible sources of contamination. Additional investigation that leads to the conclusion that the issue is systemic is also covered. The paper then focuses on the containment effort as well as root cause identification at the manufacturers. It was concluded that the failure mechanism causing the short circuit in the failed PCB is due to ionic contamination trapped inside the PCB. The normal chemistry required to process the plated through holes contaminated the voids/fractures created by drilling process.

Root Cause Analysis of a Connector Time-Delayed Fracture

2015 ◽  
Author(s):  
Prabjit Singh ◽  
Ying Yu ◽  
Robert E. Davis
Keyword(s):  
Printed Circuit Board ◽  
Ceramic Substrate ◽  
Circuit Board ◽  
Delayed Fracture ◽  
Ceramic Substrates ◽  
Printed Circuit ◽  
Root Cause ◽  
Chip Carrier ◽  
Electrical Connections ◽  
Grain Boundary Grooves

Abstract A land-grid array connector, electrically connecting an array of plated contact pads on a ceramic substrate chip carrier to plated contact pads on a printed circuit board (PCB), failed in a year after assembly due to time-delayed fracture of multiple C-shaped spring connectors. The land-grid-array connectors analyzed had arrays of connectors consisting of gold on nickel plated Be-Cu C-shaped springs in compression that made electrical connections between the pads on the ceramic substrates and the PCBs. Metallography, fractography and surface analyses revealed the root cause of the C-spring connector fracture to be plating solutions trapped in deep grain boundary grooves etched into the C-spring connectors during the pre-plating cleaning operation. The stress necessary for the stress corrosion cracking mechanism was provided by the C-spring connectors, in the land-grid array, being compressed between the ceramic substrate and the printed circuit board.

Application of Lock-in Thermography on PCB for Fault Localization and Validation of Failure Mechanism Due to External Discrete Component Variation

2010 ◽  
Author(s):  
William Ng ◽  
Kevin Weaver ◽  
Zachary Gemmill ◽  
Herve Deslandes ◽  
Rudolf Schlangen
Keyword(s):  
Failure Mechanism ◽  
Integrated Circuit ◽  
Printed Circuit Board ◽  
Hot Spot ◽  
Circuit Board ◽  
Discrete Component ◽  
Printed Circuit ◽  
Thermal Signature ◽  
Lock In

Abstract This paper demonstrates the use of a real time lock-in thermography (LIT) system to non-destructively characterize thermal events prior to the failing of an integrated circuit (IC) device. A case study using a packaged IC mounted on printed circuit board (PCB) is presented. The result validated the failing model by observing the thermal signature on the package. Subsequent analysis from the backside of the IC identified a hot spot in internal circuitry sensitive to varying value of external discrete component (inductor) on PCB.

Microhardness Testing on Via Fill Material for Via In Pad Technology

2003 ◽  
Author(s):  
Norman J. Armendariz ◽  
Carolyn McCormick
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Strong Dependence ◽  
Circuit Board ◽  
Electrical Performance ◽  
Gravimetric Analysis ◽  
Passive Components ◽  
Root Cause ◽  
Fill Material ◽  
Signal Routing

Abstract Via in pad PCB (Printed Circuit board) technology for passive components such as chip capacitors and resistors, provides the potential for improved signal routing density and reduced PCB area. Because of these improvements there is the potential for PCB cost reduction as well as gains in electrical performance through reduced impedance and inductance. However, not long after the implementation, double digit unit failures for solder joint electrical opens due to capacitor “tombstoning” began to occur. Failure modes included via fill material (solder mask) protrusion from the via as well as “out gassing” and related “tombstoning.” This failure analysis involved investigating a strong dependence on PCB supplier and, less obviously, manufacturing site. Other factors evaluated included via fill material, drill size, via fill thermal history and via fill amount or fill percent. The factor most implicated was incomplete cure of the via fill material. Previous thermal gravimetric analysis methods to determine level of polymerization or cure did not provide an ability to measure and demonstrate via fill cure level in small selected areas or its link to the failures. As a result, there was a metrology approach developed to establish this link and root-cause the failures in the field, which was based on microhardness techniques and noncontact via fill measuring metrologies.

scholarly journals Decarbonization of Industrial Energy Systems: A Case Study of Printed Circuit Board manufacturing

2021 ◽  
Author(s):  
Carles Ribas Tugores ◽  
Gerald Birngruber ◽  
Jürgen Fluch ◽  
Angelika Swatek ◽  
Gerald Schweiger
Keyword(s):  
Printed Circuit Board ◽  
Energy Systems ◽  
Circuit Board ◽  
Printed Circuit ◽  
Printed Circuit Board Manufacturing ◽  
Industrial Energy

scholarly journals Locate faulty components by IR based Direct Current Injection method with Analog Signature Analysis

2021 ◽  
Author(s):  
Zhifeng Zhu ◽  
Paul Leone
Keyword(s):  
Direct Current ◽  
Printed Circuit Board ◽  
Failure Modes ◽  
High Efficiency ◽  
Circuit Board ◽  
Signature Analysis ◽  
Printed Circuit Board Assembly ◽  
Component Failure ◽  
Printed Circuit ◽  
Circuit Board Assembly

Abstract This article describes a method to integrate Analog Signature Analysis (ASA) into IR based Direct Current Inject method (IRDCI) for Printed Circuit Board Assembly failure analysis, which extends IRDCI application from diagnostic shorted power rails to any measurement locations that show signature differences. Also, it extends the application of component failure modes from electrical short to breakdown or degradation that can be identified by signature comparison and still keep high efficiency to eliminate the needs to guess and remove suspected faulty components one by one from the board to validate.

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