Board-Level Solder Joint Reliability Study of Land Grid Array Packages for RF Applications Using a Laser Ultrasound Inspection System

2007 ◽  
Author(s):  
Jin Yang ◽  
Lizheng Zhang ◽  
I. Charles Ume ◽  
Camil Ghiu ◽  
George White
Keyword(s):  
Solder Joint ◽  
Inspection System ◽  
Laser Ultrasound ◽  
Reliability Study ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Rf Applications ◽  
Ultrasound Inspection ◽  
Board Level

Board-Level Solder Joint Reliability Study of Land Grid Array Packages for RF Application Using a Laser Ultrasound Inspection System

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Jin Yang ◽  
Lizheng Zhang ◽  
I. Charles Ume ◽  
Camil Ghiu ◽  
George White
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
Thermal Loading ◽  
Inspection System ◽  
Laser Ultrasound ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Joint Quality ◽  
Ultrasound Inspection ◽  
Board Level

Microelectronics packaging technology has evolved from through-hole, and bulk configuration to surface-mount, and small-profile ones. Today’s electronics industry is also transiting from SnPb to Pb-free to meet environmental requirements. Land grid array (LGA) package has been becoming popular in portable electronics in terms of low profile on the printed wiring boards and direct Pb-free assembly process compatibility. With the package profile shrinking and operating power increasing, solder joint quality and reliability has become a major concern in microelectronics manufacturing. The solder joint failure at the package level or board level will cause electronic devices not to function during service. In this paper, board-level solder joint reliability of the LGA packages under thermal loading is studied through thermal cycling tests. A novel laser ultrasound-interferometric system developed by the authors is applied to inspect solder joint quality during the thermal cycling tests. While the laser ultrasound inspection technique has been successfully applied to flip chips and chip scale packages, this study is the first application of this technique to overmolded packages. In this study, it is found out that the LGA packages can withstand 1000 temperature cycles without showing crack initiation or other failure mechanisms in the solder joints. The laser ultrasound inspection results match the visual observation and X-ray inspection results. This study demonstrates the feasibility of this system to solder joint quality inspection of overmolded packages. In particular, the devices constituting the objective of this study are radio frequency modules, which are encapsulated through overmolding and are mounted on a typical four-layer FR4 board through LGA terminations.

Reliability of Underfilled Chip Scale Packages Attached With Heat Sink

2005 ◽  
Author(s):  
Saketh Mahalingam ◽  
Ashutosh Joshi ◽  
Joseph Lacey ◽  
Kunal Goray
Keyword(s):  
Solder Joint ◽  
Heat Sink ◽  
Operating Temperature ◽  
Ball Grid Array ◽  
Solder Joint Reliability ◽  
Proper Understanding ◽  
Joint Reliability ◽  
Board Level ◽  
Inelastic Strains ◽  
Underfill Material

Chip Scale Packages (CSP) are ideal intermediates between Direct Chip Attach (DCA) and Ball Grid Array (BGA) technologies in terms of both size and cost. Depending upon the application, chip scale packages are either underfilled for better solder joint reliability or are attached with a heat sink to keep the operating temperature of the chip under control. In many applications, as discussed in this paper, both an underfill and a heat sink are required. Quite expectedly the addition of two more materials, heat sink and adhesive, in the board level assembly results in fresh reliability concerns. In particular, the requirements on the underfill material and the heat sink attach adhesive are more rigorous and needless to say, a proper understanding of process and material issues is needed to make such a choice. The inelastic strains experienced by the solder joint (related to the underfill) and the peeling stresses at the heat sink attach adhesive interfaces (related to the thermal adhesive) are used as metric for comparing the number of material choices that are available. Based on the results, it is shown that it is important to choose materials that are thermo-mechanically matched with the rest of the system.

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