Board level reliability of PBGA using flex substrate

Prediction of damage and fatigue life of high-temperature flip chip assembly interconnections at operations

“…These performance threatening conditions also arise during power on/off and in severe cases none operating and then operating in high-temperature shift conditions -for HTE. It is pertinent to mention that high-temperature reliability of microelectronic chip on board is influenced significantly by the thermal expansion coefficients (CTEs) of bonded materials of its solder joint [2,[10][11][12][13] and also the brittle IMC formed at the interfaces of solder and bond pads [14,15].…”

“…The viscoplastic damage, measured by indicators such as strain energy density and plastic work, accumulates cycle by cycle and eventually culminates in solder joint failure through fatigue cracking mechanism. Metallurgical reactions involving solder alloys, copper in the bond pad and pad metalisation during both reflow assembly process and life operations produce and grow IMC respectively at the interfaces of solder bulk and the bond pads [12,[16][17][18][19][20][21]. The lead-free solder used in FC manufacture contains Sn3.9Ag0.6Cu alloy materials [22].…”

Effects of Different Kinds of Underfills and Temperature–Humidity Treatments on Drop Reliability of Board-Level Packages

“…1,2 With increasing miniaturization of electronic products, these handheld products are very susceptible to dropping or mechanical impact. Mechanical shocks resulting from mishandling during transportation or customer usage may cause solder joint failures, which lead to product malfunction.…”

“…17,18 Many studies have been performed to investigate the drop reliability of board-level packages, varying parameters such as drop test conditions, under bump metallurgy, solder, PCB finishes, and pad structure. [1][2][3][4][5][6][7][8][9][10][11][12][13] Nevertheless, insufficient studies have investigated the drop reliability of board-level packages with different kinds of underfill under hygrothermal and mechanical stresses. Therefore, we investigated the hygrothermal and mechanical reliability of board-level packages with various underfills using the temperature and humidity (TH) test and drop test.…”

Improvement of Board Level Reliability for μBGA Solder Joints Using Underfill

“…[1][2][3] A major issue in applying BGA packages and CSP has been board-level reliability, [4][5][6] which is a particularly critical issue in portable electronic products such as PDAs, cellular phones, etc. In these products, harsh service conditions such as mechanical impacts, 7) vibration and bending 8,9) add to cyclical thermal stresses induced by differences in the Coefficient of Thermal Expansion (CTE) between the chip and the printed circuit board (PCB).…”