A paper describes advanced ceramic column grid array (CCGA) packaging interconnects technology test objects that were subjected to extreme temperature thermal cycles. CCGA interconnect electronic package printed wiring boards (PWBs) of polyimide were assembled, inspected nondestructively, and, subsequently, subjected to extreme-temperature thermal cycling to assess reliability for future deep-space, short- and long-term, extreme-temperature missions.
The test hardware consisted of two CCGA717 packages with each package divided into four daisy-chained sections, for a total of eight daisy chains to be monitored. The package is 33×33 mm with a 27×27 array of 80%/20% Pb/Sn columns on a 1.27-mm pitch.
The change in resistance of the daisy-chained CCGA interconnects was measured as a function of the increasing number of thermal cycles. Several catastrophic failures were observed after 137 extreme-temperature thermal cycles, as per electrical resistance measurements, and then the tests were continued through 1,058 thermal cycles to corroborate and understand the test results. X-ray and optical inspection have been made after thermal cycling. Optical inspections were also conducted on the CCGA vs. thermal cycles. The optical inspections were conclusive; the x-ray images were not.
Process qualification and assembly is required to optimize the CCGA assembly, which is very clear from the x-rays. Six daisy chains were open out of seven daisy chains, as per experimental test data reported. The daisy chains are open during the cold cycle, and then recover during the hot cycle, though some of them also opened during the hot thermal cycle.
This work was done by Rajeshuni Ramesham of Caltech for NASA’s Jet Propulsion Laboratory. NPO-47341
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Reliability of Ceramic Column Grid Array Interconnect Packages Under Extreme Temperatures
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Overview
The document titled "Reliability of Ceramic Column Grid Array (CCGA) Interconnect Packages Under Extreme Temperatures for Space Applications" (NPO 47341) focuses on the reliability assessment of CCGA packages, which are increasingly utilized in space applications due to their high interconnect density and superior thermal and electrical performance. These packages are critical for various functions, including logic and microprocessor operations, telecommunications, flight avionics, and payload electronics.
One of the primary concerns addressed in the document is the reliability of CCGA packages under extreme temperature conditions, as these packages exhibit less solder joint strain relief compared to traditional leaded packages. This characteristic makes their reliability crucial for both short-term and long-term space missions. The document outlines the temperature ranges relevant to different space missions, including those on Titan, Europa, asteroids, comets, the Moon, and Mars, which require hardware to operate under both extremely cold and hot temperatures, with significant diurnal temperature variations.
To ensure the reliability of CCGA packages, the document highlights the need for rigorous testing. It notes that current NASA standards for thermal cycling range from -55°C to +100°C, but the research presented encompasses a broader range of -185°C to +125°C. This expanded range is particularly important for deep space missions and addresses a gap in existing literature, as there has been no systematic experimental data published on CCGA reliability in such extreme temperatures.
The novelty of this research lies in its comprehensive experimental test results, which provide valuable insights into the performance of CCGA packages under conditions that have not been previously documented. The findings are expected to significantly contribute to the understanding of CCGA reliability in extreme environments, thereby enhancing the design and implementation of reliable electronic systems for future space missions.
In summary, this document serves as a critical resource for understanding the reliability of CCGA interconnect packages in extreme temperatures, emphasizing the importance of this research for the success of NASA's deep space exploration initiatives. The results are anticipated to have broader technological, scientific, and commercial applications beyond aerospace.
