The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Michael G. Pecht - One of the best experts on this subject based on the ideXlab platform.
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Stress Relaxation Testing of Stamped Metal Land-Grid-Array Sockets
IEEE Transactions on Device and Materials Reliability, 2010Co-Authors: Vidyu Challa, Leoncio D. Lopez, Michael Osterman, Michael G. PechtAbstract:Stress Relaxation in stamped metal LGA sockets can result in a loss of normal force and an increase in contact resistance, potentially leading to a failure. This paper describes an approach for determining the risks from Stress Relaxation in stamped metal LGA sockets by taking into account the effect of Joule heating of the socket contacts. Stress Relaxation data were obtained at different temperatures and strain values, representative of both operating and overload conditions. Contact resistance measurements were conducted as the force was varied to determine the minimum force below which Stress Relaxation is likely to cause failure. Joule heating of the socket contacts was found to cause a measurable rise in temperature with a typical value of ~40°C above the unpowered state of 90°C at the maximum rated current of 3 A for the socket being studied. This temperature rise was determined to be a significant factor in Stress Relaxation and was found to cause an average reduction in normal force by ~26%. The properties of the polymer housing were found to be sensitive to Joule heating effects and to have a significant influence on the Stress Relaxation behavior of the socket.
Vidyu Challa - One of the best experts on this subject based on the ideXlab platform.
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Stress Relaxation Testing of Stamped Metal Land-Grid-Array Sockets
IEEE Transactions on Device and Materials Reliability, 2010Co-Authors: Vidyu Challa, Leoncio D. Lopez, Michael Osterman, Michael G. PechtAbstract:Stress Relaxation in stamped metal LGA sockets can result in a loss of normal force and an increase in contact resistance, potentially leading to a failure. This paper describes an approach for determining the risks from Stress Relaxation in stamped metal LGA sockets by taking into account the effect of Joule heating of the socket contacts. Stress Relaxation data were obtained at different temperatures and strain values, representative of both operating and overload conditions. Contact resistance measurements were conducted as the force was varied to determine the minimum force below which Stress Relaxation is likely to cause failure. Joule heating of the socket contacts was found to cause a measurable rise in temperature with a typical value of ~40°C above the unpowered state of 90°C at the maximum rated current of 3 A for the socket being studied. This temperature rise was determined to be a significant factor in Stress Relaxation and was found to cause an average reduction in normal force by ~26%. The properties of the polymer housing were found to be sensitive to Joule heating effects and to have a significant influence on the Stress Relaxation behavior of the socket.
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Stress Relaxation in a commercial stamped metal land grid array socket
2008 58th Electronic Components and Technology Conference, 2008Co-Authors: Vidyu Challa, Michael Osterman, Myra Torres, Michael Pecht, Leoncio LopezAbstract:Land grid array (LGA) sockets provide a solderless printed circuit board (PCB) attachment method for microprocessors that require high interconnect density. Stamped metal LGA sockets consist of metal contacts embedded in a plastic housing, that form the electrical and mechanical connection between the component and PCB by means of compression. To achieve a stable contact interface between the socket and component/PCB, it is necessary to maintain a minimum normal force. Stress Relaxation results in a loss of normal force, and could cause an increase in contact resistance, potentially leading to a failure. Contact alloy manufacturers report Stress Relaxation data for the alloy in strip form. This data may not be an appropriate measure of the Stress Relaxation in an LGA socket because it does not take into account the geometry of the increasingly miniaturized contacts or the effect of the surrounding polymer. This paper therefore aims to study the Stress Relaxation of stamped metal LGA sockets, by testing the actual socket in its final processed form and capturing the effect of the polymer on Stress Relaxation. Furthermore, by testing small pieces of the socket, independent of the loading assembly, a method of studying the temperature and load dependence of Stress Relaxation and the effect on the socket's electrical behavior was demonstrated, without the need for system level testing.
Michael Osterman - One of the best experts on this subject based on the ideXlab platform.
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Stress Relaxation Testing of Stamped Metal Land-Grid-Array Sockets
IEEE Transactions on Device and Materials Reliability, 2010Co-Authors: Vidyu Challa, Leoncio D. Lopez, Michael Osterman, Michael G. PechtAbstract:Stress Relaxation in stamped metal LGA sockets can result in a loss of normal force and an increase in contact resistance, potentially leading to a failure. This paper describes an approach for determining the risks from Stress Relaxation in stamped metal LGA sockets by taking into account the effect of Joule heating of the socket contacts. Stress Relaxation data were obtained at different temperatures and strain values, representative of both operating and overload conditions. Contact resistance measurements were conducted as the force was varied to determine the minimum force below which Stress Relaxation is likely to cause failure. Joule heating of the socket contacts was found to cause a measurable rise in temperature with a typical value of ~40°C above the unpowered state of 90°C at the maximum rated current of 3 A for the socket being studied. This temperature rise was determined to be a significant factor in Stress Relaxation and was found to cause an average reduction in normal force by ~26%. The properties of the polymer housing were found to be sensitive to Joule heating effects and to have a significant influence on the Stress Relaxation behavior of the socket.
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Stress Relaxation in a commercial stamped metal land grid array socket
2008 58th Electronic Components and Technology Conference, 2008Co-Authors: Vidyu Challa, Michael Osterman, Myra Torres, Michael Pecht, Leoncio LopezAbstract:Land grid array (LGA) sockets provide a solderless printed circuit board (PCB) attachment method for microprocessors that require high interconnect density. Stamped metal LGA sockets consist of metal contacts embedded in a plastic housing, that form the electrical and mechanical connection between the component and PCB by means of compression. To achieve a stable contact interface between the socket and component/PCB, it is necessary to maintain a minimum normal force. Stress Relaxation results in a loss of normal force, and could cause an increase in contact resistance, potentially leading to a failure. Contact alloy manufacturers report Stress Relaxation data for the alloy in strip form. This data may not be an appropriate measure of the Stress Relaxation in an LGA socket because it does not take into account the geometry of the increasingly miniaturized contacts or the effect of the surrounding polymer. This paper therefore aims to study the Stress Relaxation of stamped metal LGA sockets, by testing the actual socket in its final processed form and capturing the effect of the polymer on Stress Relaxation. Furthermore, by testing small pieces of the socket, independent of the loading assembly, a method of studying the temperature and load dependence of Stress Relaxation and the effect on the socket's electrical behavior was demonstrated, without the need for system level testing.
Leoncio D. Lopez - One of the best experts on this subject based on the ideXlab platform.
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Stress Relaxation Testing of Stamped Metal Land-Grid-Array Sockets
IEEE Transactions on Device and Materials Reliability, 2010Co-Authors: Vidyu Challa, Leoncio D. Lopez, Michael Osterman, Michael G. PechtAbstract:Stress Relaxation in stamped metal LGA sockets can result in a loss of normal force and an increase in contact resistance, potentially leading to a failure. This paper describes an approach for determining the risks from Stress Relaxation in stamped metal LGA sockets by taking into account the effect of Joule heating of the socket contacts. Stress Relaxation data were obtained at different temperatures and strain values, representative of both operating and overload conditions. Contact resistance measurements were conducted as the force was varied to determine the minimum force below which Stress Relaxation is likely to cause failure. Joule heating of the socket contacts was found to cause a measurable rise in temperature with a typical value of ~40°C above the unpowered state of 90°C at the maximum rated current of 3 A for the socket being studied. This temperature rise was determined to be a significant factor in Stress Relaxation and was found to cause an average reduction in normal force by ~26%. The properties of the polymer housing were found to be sensitive to Joule heating effects and to have a significant influence on the Stress Relaxation behavior of the socket.
Leoncio Lopez - One of the best experts on this subject based on the ideXlab platform.
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Stress Relaxation in a commercial stamped metal land grid array socket
2008 58th Electronic Components and Technology Conference, 2008Co-Authors: Vidyu Challa, Michael Osterman, Myra Torres, Michael Pecht, Leoncio LopezAbstract:Land grid array (LGA) sockets provide a solderless printed circuit board (PCB) attachment method for microprocessors that require high interconnect density. Stamped metal LGA sockets consist of metal contacts embedded in a plastic housing, that form the electrical and mechanical connection between the component and PCB by means of compression. To achieve a stable contact interface between the socket and component/PCB, it is necessary to maintain a minimum normal force. Stress Relaxation results in a loss of normal force, and could cause an increase in contact resistance, potentially leading to a failure. Contact alloy manufacturers report Stress Relaxation data for the alloy in strip form. This data may not be an appropriate measure of the Stress Relaxation in an LGA socket because it does not take into account the geometry of the increasingly miniaturized contacts or the effect of the surrounding polymer. This paper therefore aims to study the Stress Relaxation of stamped metal LGA sockets, by testing the actual socket in its final processed form and capturing the effect of the polymer on Stress Relaxation. Furthermore, by testing small pieces of the socket, independent of the loading assembly, a method of studying the temperature and load dependence of Stress Relaxation and the effect on the socket's electrical behavior was demonstrated, without the need for system level testing.
