Measurement of Moisture-Induced Packaging Stress With Piezoresistive Sensors

• Published in: IEEE transactions on advanced packaging Vol. 30; no. 3; pp. 393 - 401
• Main Authors: LWO, Ben-Je, LIN, Chih-Shiang
• Format: Journal Article
• Language: English
• Published: Piscataway, NY IEEE 01.08.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic measurements; Acoustic microscopes; Acoustic sensors; Acoustic wave devices, piezoelectric and piezoresistive devices; Applied sciences; Arrays; Design. Technologies. Operation analysis. Testing; Electronic packaging; Electronics; Exact sciences and technology; hygroscopic mismatch; Integrated circuits; Microelectronics; Moisture measurement; moisture-induced effect; Monitoring; Packages; Packaging; Piezoresistance; piezoresistive sensor; popcorn failure; Recording; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensor phenomena and characterization; Sensors; Stress measurement; Stresses; Thermal stresses; Thermal stress; Piezoresistive sensor; In situ; hygroscopic mismatch; Rupture; Microelectronics; Failures; Mismatching; BGA technology; Integrated circuit bonding; Scanning microscope; Humidity effect; Stress distribution; moisture-induced effect; Acoustic microscopy; popcorn failure; Electronic packaging; Soldered joint; Recording; Reliability; Stress measurement
• ISSN: 1521-3323; 1557-9980
• DOI: 10.1109/TADVP.2007.898603

Moisture is one of the major contributing factors in fracture and reliability issues for microelectronic packaging. To characterize the moisture-induced stress distribution inside the packaging structure, an in situ , quantitative, and nondestructive experimental methodology is needed. This paper proposes the use of piezoresistive sensors to measure moisture-induced stress in a plastic low profile, fine pitch, ball grid array (LFBGA) packaging. The measurements include hygroscopic swelling stress extractions and real-time stress monitoring of the popcorn phenomenon, and the results associated with gravimetric analyses are reported. Postreflow scanning acoustic microscope (SAM) inspection results and cross section observations are used as experimental verification. Comparing with thermal stresses previously measured on the same package, it is found that the hygroscopic mismatch stress is significant and important for package engineers. In addition, piezoresistive sensors were proven useful in this work for recording popcorn occurrence and monitoring the stress drops at the popcorn initiation.