Interfacial behavior of a flip-chip structure under thermal testing

Abstract

Abstract-In this paper, the interfacial behavior of a flip-chip structure under thermal testing was investigated using high sensitivity, real-time Moiré interferometry. The model package studied was a sandwich structure consisting of a silicon chip, epoxy underfill and FR4 substrate. The behavior of FR4-underfill and silicon-underfill interfaces of the specimen under certain thermal loading was examined. The results show that the shear strain variation increases significantly along the interfaces, with the maximum shear strain concentration occurring at the edge of the specimen. At the edge, the maximum shear strain occurs at the silicon-underfill interface, and the FR4-underfill interface experiences a slightly lower shear strain. The creep effect is more dominant in the FR4-underfill interface when the specimen is heated for 2 h at 100 C. Upon cooling to 20 C, both the interfaces of the specimen experience partial strain recovery.

Measurements of surface deformations and strains using an AFM moiré method

“…A full-field optical moiré method [17] has the advantage of low cost. Its moiré pattern can give a picture about the whole distribution of the deformations in the whole surface.…”

“…Its moiré pattern can give a picture about the whole distribution of the deformations in the whole surface. However, to accurately study the deformation/strain in a small area, a micro moiré method [17,18] is needed.…”

Thermal Simulation Analysis of Internal Control Circuit Board of Steering Gear Box Based on COMSOL Three-Dimensional Simulation Software

“…Once the thermal resistance of the heat transfer path is studied, a feasible reference scheme is given for the heat dissipation of future power amplifier chips. Zhong et al [ 3 ] used high-sensitivity real-time Moiré interferometry to study the interface behavior of flip-chip structures under thermal test conditions. Su et al [ 4 ] taking the chip packaging structure as a model, using infrared thermal imaging technology, studied the change law of the chip thermal stress with the change of current, and it is found that the chip thermal stress changes logarithmically with the change of the working current.…”

Recent Applications of Moiré Interferometry

“…They were employed to study the temperature-dependent thermo-mechanical behavior. The schemes were implemented with convectiontype or conduction-type environmental chambers that provide the temperature control required in accelerated thermal cycling (isothermal loading) [35,41,[50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. Park et al…”