The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform
Tai Chong Chai - One of the best experts on this subject based on the ideXlab platform.
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the mechanics of the Solder ball shear test and the effect of shear rate
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Julian Yan Hon Chia, Brian Cotterell, Tai Chong ChaiAbstract:Abstract A test rig was developed to do high speed Solder ball shear tests on a servohydraulic testing machine. Shear tests were conducted over a range of shear rates on eutectic tin–lead and lead-free Solder balls that were mounted on a chip scale package (CSP) with a Solder mask defined (SMD) ball grid array (BGA) configuration and on the Cu Pads in a maskless printed wire board (PWB). The high speed ball shear test was found to induce a brittle Solder/Pad interface fracture that resembles the fracture in lead-free interconnects of board mounted microelectronic devices that have been subjected to mechanical shock. An approximate static analysis of the Solder ball shear test has been developed that enables the plastic, fracture, and friction work to be separated. This analysis suggests that the specific work after maximum load obtained for low shear rate is closely related to the toughness of the Solder. Provided the fracture was stable, the specific work after maximum load was relatively insensitive to shear rate suggesting that the Solder toughness is also rate insensitive. The shear strength and total specific shear work all increase with shear rate.
Brian Cotterell - One of the best experts on this subject based on the ideXlab platform.
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the mechanics of the Solder ball shear test and the effect of shear rate
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Julian Yan Hon Chia, Brian Cotterell, Tai Chong ChaiAbstract:Abstract A test rig was developed to do high speed Solder ball shear tests on a servohydraulic testing machine. Shear tests were conducted over a range of shear rates on eutectic tin–lead and lead-free Solder balls that were mounted on a chip scale package (CSP) with a Solder mask defined (SMD) ball grid array (BGA) configuration and on the Cu Pads in a maskless printed wire board (PWB). The high speed ball shear test was found to induce a brittle Solder/Pad interface fracture that resembles the fracture in lead-free interconnects of board mounted microelectronic devices that have been subjected to mechanical shock. An approximate static analysis of the Solder ball shear test has been developed that enables the plastic, fracture, and friction work to be separated. This analysis suggests that the specific work after maximum load obtained for low shear rate is closely related to the toughness of the Solder. Provided the fracture was stable, the specific work after maximum load was relatively insensitive to shear rate suggesting that the Solder toughness is also rate insensitive. The shear strength and total specific shear work all increase with shear rate.
S Ricky W Lee - One of the best experts on this subject based on the ideXlab platform.
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assessment of Solder Pad cratering strength using cold pin pull test method with pre fabricated pin arrays
Electronic Components and Technology Conference, 2013Co-Authors: Qiming Zhang, Chaora Yang, Mia Tao, Fubi Song, S Ricky W LeeAbstract:Hot pin pull test is frequently used for the Pad crater evaluation. Although it carries several merits, it still has certain drawbacks such as time consuming and causing potential thermal impact on the PCB during the pin attachment process. In this paper, an innovative cold pin pull test method with pre-fabricated pin arrays is introduced. A set of fixture is designed and manufactured in advance. An array of pins can be attached to the test board at one time. With this fixture, instead of attaching the pin one by one, the test panel with pin arrays can be prepared after only two times of reflow without severe thermal impact. Compared with the conventional cold ball pull tests, this newly developed method cannot only equally exhibit the Pad crater characteristics of the PCB, but also reduces the scattering in testing results. These conclusions are well proven by the experimental data generated in the present study.
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development of innovative cold pin pull test method for Solder Pad crater evaluation
International Conference on Electronic Materials and Packaging, 2012Co-Authors: Qiming Zhang, Chaora Yang, Mia Tao, Fubi Song, S Ricky W LeeAbstract:Hot pin pull test is one of the testing methods frequently used in the Pad crater evaluation. Although it carries several merits comparing with the other testing methods, it still has certain drawbacks such as time consuming and the potential thermal impact on the PCB copper Pad during the pin attachment process. In this paper, an innovative cold pin pull testing method is introduced. Using a set of fixtures designed and manufactured in advance, an array of pins can be attached to the pre-deposited Solder balls at one time. Therefore, instead of attaching the pin one by one, the test panel with pin arrays can be prepared after only two times of reflow. Compared with conventional cold ball pull tests, this newly developed method can not only equally exhibit the Pad crater characteristics of the PCB, but also reduce the testing variations, which could be proven by experimental data generated in the present study.
P Orgese - One of the best experts on this subject based on the ideXlab platform.
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joint level test methods for Solder Pad cratering investigations
Journal of Electronic Packaging, 2011Co-Authors: Ia Roggema, Venkatesh Arasanipalai Raghava, P OrgeseAbstract:The introduction of less compliant lead free Solders together with weaker and more brittle laminate materials has led to major concerns with respect to the resistance of the latter to Pad cratering. For purposes of laminate selection as well as for the quantification of acceptable handling and use conditions, there is a general interest in the testing for cratering at the joint level, rather than by testing entire assemblies. Joint level testing is cheaper, faster, and offers more quantitative results. Joint level testing also allows the elimination of confounding factors such as PCB and component stiffness. Developing test procedures and testing, it is important to distinguish between wear out under repeated loads and the failure due to a single overstress. Correlations between these two damage scenarios are largely fortuitous. Focusing on strength testing we have compared alternative methods and identified the most relevant approach. Occasions may arise where shear testing is the most appropriate, but most Pad cratering scenarios are best represented by so-called Hot Bump Pull at an angle of about 30° to the Pad normal. Replacing the Solder balls by paste deposits or pulling in a direction normal to the Pad may lead to a different ranking of materials and otherwise obscure systematic trends. We also recommend taking loading rate and temperature effects into account.
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effects of pre stressing on Solder joint failure by Pad cratering
Electronic Components and Technology Conference, 2010Co-Authors: Venkatesh Arasanipalai Raghava, Ia Roggema, Michael Meilunas, P OrgeseAbstract:The present work addresses a significant risk generally overlooked in the design and accelerated testing of high reliability electronics. Manufacturers of servers and other expensive high reliability electronics equipment are becoming increasingly concerned with the risk of Solder Pad cratering. Their focus is, however, on cratering in testing, handling or transport, while the risk of premature wear-out due to thermal excursions (cycling) in service is completely ignored. This is a result of reliability testing that almost invariably addresses individual loading conditions separately. Under such conditions it is for example extremely rare for electrical failures in thermal cycling or high-cycle vibration testing to be associated with Pad cratering. The present paper shows how manufacturers of high reliability equipment intended for mechanically protected or benign service conditions may be missing a significant risk of invisible damage induced in testing, handling or transport which may change the failure mode in service. We present first results of a systematic effort aimed at redefining currently proposed Pad cratering test protocols.
Julian Yan Hon Chia - One of the best experts on this subject based on the ideXlab platform.
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the mechanics of the Solder ball shear test and the effect of shear rate
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Julian Yan Hon Chia, Brian Cotterell, Tai Chong ChaiAbstract:Abstract A test rig was developed to do high speed Solder ball shear tests on a servohydraulic testing machine. Shear tests were conducted over a range of shear rates on eutectic tin–lead and lead-free Solder balls that were mounted on a chip scale package (CSP) with a Solder mask defined (SMD) ball grid array (BGA) configuration and on the Cu Pads in a maskless printed wire board (PWB). The high speed ball shear test was found to induce a brittle Solder/Pad interface fracture that resembles the fracture in lead-free interconnects of board mounted microelectronic devices that have been subjected to mechanical shock. An approximate static analysis of the Solder ball shear test has been developed that enables the plastic, fracture, and friction work to be separated. This analysis suggests that the specific work after maximum load obtained for low shear rate is closely related to the toughness of the Solder. Provided the fracture was stable, the specific work after maximum load was relatively insensitive to shear rate suggesting that the Solder toughness is also rate insensitive. The shear strength and total specific shear work all increase with shear rate.