PCB Pad Cratering – Characterization Techniques and Challenges

2008 ◽  
Author(s):  
Satish Parupalli ◽  
Keith Newman ◽  
Mudasir Ahmad
Keyword(s):  
Working Group ◽  
Solder Ball ◽  
Printed Circuit Board ◽  
Phase 1 ◽  
Test Methods ◽  
Circuit Board ◽  
Mechanical Fracture ◽  
Characterization Techniques ◽  
Pad Cratering ◽  
Phase 2 Study

Abstract Some standard characterization techniques (solder ball pull, solder ball shear, etc.) exist for the assessment of solder ball mechanical fracture strength; however, it is not clear if these test methods would also provide characterization of printed circuit board (PCB) pad cratering susceptibility. This paper provides an overview of test methods being investigated by a PCB pad crater industry working group. The scope of this industry working group is two-fold: standardization of PCB pad crater crack characterization and measurement methods and development of a quantitative quality metric for PCB pad cratering. Though the test methods were successful in creating pad craters; there was not enough distinction between the various laminate material types based on the output parameters. Based on the readings from Phase 1 study and available literature, the team is in the process of completing the Phase 2 study which will be reported at a later stage.

Printed Circuit Board Pad Crater Test Methods and Sample Design

2012 ◽  
Author(s):  
Todd Embree ◽  
Deassy Novita ◽  
Gary Long ◽  
Satish Parupalli
Keyword(s):  
Test Data ◽  
Printed Circuit Board ◽  
Test Methods ◽  
Circuit Board ◽  
Lead Free ◽  
Sample Design ◽  
Printed Circuit ◽  
Highly Sensitive ◽  
Halogen Free ◽  
Lead Free Solders

The continual drive toward smaller second level interconnect dimensions, along with the introduction of Halogen-Free circuit board materials and increased process temperatures of Lead-Free solders, have all contributed to a more frequent occurrence of Pad Crater damage in circuit board materials during manufacturing and test processes. This paper addresses the methodology and test data of some common industry methods used to evaluate Pad Crater strength in circuit board materials. Pad Crater test data is highly sensitive to sample design; as a result a discussion of sample design criteria is also included.

scholarly journals DDR4 BER Degradation Due to Crack in FBGA Package Solder Ball

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1445
Author(s):  
Muhammad Waqar ◽  
Geunyong Bak ◽  
Junhyeong Kwon ◽  
Sanghyeon Baeg
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Solder Ball ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Thermal Coefficient ◽  
Electrical Model ◽  
Fine Pitch ◽  
Solder Balls ◽  
Board Material

This paper measures bit error rate degradation in DDR4 due to crack in fine pitch ball grid array (FBGA) package solder ball. Thermal coefficient mismatch between the package and printed circuit board material causes cracks to occur in solder balls. These cracks change the electrical model of the solder ball and introduce parallel capacitance in the electrical model. The capacitance causes higher frequency attenuation and closes the data eye. As the data rate of the DDR4 increases there are more data eye closures. The data eye closure causes bit error rate (BER) degradation as the timing margin and voltage margin decreases. This degradation reduces the reliability of the system and causes more intermittent errors. DDR4 data line is loaded with a parallel capacitive element to mimic a crack in solder ball. The measured data eye shows a decrease in eye width. Bathtub plots are created for comparison of cracked solder ball and intact solder ball. The bathtub plots show the BER degradation due to crack in solder ball.

scholarly journals Test Solution for Heatsinks in Power Electronics Applications

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1020
Author(s):  
Davide Piumatti ◽  
Stefano Borlo ◽  
Matteo Quitadamo ◽  
Matteo Sonza Reorda ◽  
Eric Giacomo Armando ◽  
...  
Keyword(s):  
Power Electronics ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
Test Methods ◽  
Circuit Board ◽  
Power Devices ◽  
Thermal Limits ◽  
Test Strategies ◽  
Dissipation System

Power electronics technology is widely used in several areas, such as in the railways, automotive, electric vehicles, and renewable energy sectors. Some of these applications are safety critical, e.g., in the automotive domain. The heat produced by power devices must be efficiently dissipated to allow them to work within their operational thermal limits. Moreover, numerous ageing effects are due to thermal stress, which causes mechanical issues. Therefore, the reliability of a circuit depends on its dissipation system, even if it consists of a simple passive heatsink mounted on the power device. During the Printed Circuit Board (PCB) production, an incorrect assembly of the heatsink can cause a worse heat dissipation with a significant increase of the junction temperatures (Tj). In this paper, three possible test strategies are compared for testing the correct assembling of heatsinks. The considered strategies are used at the PCB end-manufacturing. The effectiveness of the different test methods considered is assessed on a case study corresponding to a Power Supply Unit (PSU).

scholarly journals Estimation of Solder Ball Collapse Height in Semiconductor Packaging Using Theoretical and Solid Modeling Techniques

2019 ◽  
pp. 1-8
Author(s):  
Jefferson Talledo
Keyword(s):  
Solder Ball ◽  
Printed Circuit Board ◽  
Cost Effective ◽  
Solid Modeling ◽  
Circuit Board ◽  
Ball Size ◽  
Short Period ◽  
Modeling Techniques ◽  
Solder Mask ◽  
Semiconductor Packages

Semiconductor packages using solder balls as interconnect to the printed circuit board (PCB) are very popular especially in mobile products like smart phones. Recent requirement to make the package much thinner is very challenging. The solder ball collapse height after the solder ball is reflowed on the package substrate metal pad would need to be tightly controlled and aligned with the required height to meet the target overall package thickness. Another challenge is that the package has to be developed in a short period of time. In this study, theoretical and solid modeling techniques were developed to estimate the solder ball collapse height and compared with actual evaluation results. With these, the solder ball collapse height could be quickly estimated to make the package design and development faster avoiding several trial evaluations on different combinations of solder ball size, substrate pad solder mask opening diameter and solder mask thickness. Based on the estimation results, using these techniques showed good agreement with actual solder ball height measurements and have now been successfully used in coming up with final package designs in a fast and cost-effective way.

Assessment of Fatigue Induced Pad Cratering With a Universal Expression of Printed Circuit Board Fatigue Resistance

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Qiming Zhang ◽  
S. W. Ricky Lee
Keyword(s):  
Printed Circuit Board ◽  
Drop Test ◽  
Circuit Board ◽  
Bending Test ◽  
Cyclic Bending ◽  
Pcb Assembly ◽  
Testing Method ◽  
Pad Cratering ◽  
Drop Tests ◽  
Board Level

Abstract Repeated loading is an important reason to cause pad cratering fatigue failure in ball grid array (BGA) device in printed circuit board (PCB) assembly. For industry application, the board level drop test is commonly applied to evaluate the pad cratering fatigue strength under the repetitive drop loading. Although this testing method is consistent with the actual service condition of BGA-PCB assembly, it is extremely time consuming in the testing operation and expensive in costs. Another fatigue evaluation testing method for BGA-PCB assembly is the board level cyclic bending test. Compare with the board level drop test, this testing method can be handled by universal testing machine automatically without manual operation during the testing process. In consequence, the cyclic bending test has the merits of simple, fast, and low costs, and it is always desirable to evaluate the repeated drop life of pad cratering with cyclic bending test. This research proposes a correlation between the cyclic bending and repetitive drop test in BGA-PCB assemblies. With assistance of finite element method, the equivalent cyclic bending testing conditions of drop tests are developed. The experimental validation is also conducted to prove accuracy of the correlation. From the analysis of finite element method and experiments, both cyclic bending tests and repetitive drop tests agree with the same strain–number of cycle (S–N) curve. This means the S–N curve can be treated as a generalized failure criterion of fatigue induced pad cratering. The conclusion is crucial for reliability design phases to prevent the pad cratering fatigue failure.

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