Importance of Bonding Atmosphere for Mechanical Reliability of Reactively Bonded Solder Joints

Self-propagating exothermic reaction bonding (SERB) technique with Al/Ni multilayer film is fascinating in the viewpoint of lots of outstanding features, such as atmosphere-independent exothermic reaction and its self-propagation. The reactively bonded solder joints with high bonded strength are required for practical use in semiconductor devices. We have investigated the fracture strength of rectangular-solid specimens with reactively bonded solder joint (Sn–3.5Ag solder/reacted NiAl/Sn–3.5Ag solder) sandwiched by single crystal silicon (SCS). In this paper, the influence of bonding atmosphere on the fracture behavior is discussed by means of four-point bending testing and fracture surface observation. The fracture strength increases with increasing pressure load during bonding. The strength of the vacuum-bonded specimens is found to be higher than that of the air-bonded specimens. The fracture surface observation results suggest that Al oxide and intermetallic compounds (IMCs) formed at the reacted NiAl layer and the SnAg solder layer, respectively, would have affected the strength of the Al/Ni SERB joints.

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Influences of Exothermic Reactive Layer and Metal Interlayer on Fracture Behavior of Reactively Bonded Solder Joints

Journal of Engineering Materials and Technology ◽

10.1115/1.4030413 ◽

2015 ◽

Vol 137 (3) ◽

Cited By ~ 11

Author(s):

Takahiro Namazu ◽

Kohei Ohtani ◽

Shozo Inoue ◽

Shugo Miyake

Keyword(s):

Film Thickness ◽

Microelectromechanical Systems ◽

Solder Joints ◽

Single Crystal Silicon ◽

Bending Test ◽

Crystal Silicon ◽

Fracture Origin ◽

Four Point Bending ◽

External Forces

Reactively bonded solder joints with Al/Ni exothermic films attract much attention in semiconductor and microelectromechanical systems (MEMS) industries. Higher bond strength of the joints is required for long-term mechanical reliability. We have investigated the strength of rectangular-solid single crystal silicon (SCS) specimens with reactively bonded Sn-3.5Ag solder joint by using specially developed four-point bending test equipment. In this paper, the influences of Al/Ni exothermic film thickness and metallic interlayer on the strength are discussed. The strength increases with increasing Al/Ni film thickness and pressure load during bonding. Metallic interlayer between the solder and SCS also affects the strength because fracture origin is dependent on the types of metals. The obtained results suggest that reacted NiAl is durable against external forces compared with the solder and interlayer.

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Effect of surface morphology and crystal orientations on fracture strength of thin film (110) single crystal silicon

2013 Transducers & Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII) ◽

10.1109/transducers.2013.6627175 ◽

2013 ◽

Cited By ~ 4

Author(s):

A. Uesugi ◽

Y. Hirai ◽

K. Sugano ◽

T. Tsuchiya ◽

O. Tabata

Keyword(s):

Thin Film ◽

Surface Morphology ◽

Single Crystal ◽

Fracture Strength ◽

Single Crystal Silicon ◽

Crystal Silicon ◽

Crystal Orientations ◽

Effect Of Surface

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Fracture Behavior of Silicon Cut with a High Power Laser

MRS Proceedings ◽

10.1557/proc-226-363 ◽

1991 ◽

Vol 226 ◽

Cited By ~ 5

Author(s):

C.C. Chao ◽

R. Chleboski ◽

E.J. Henderson ◽

C.K. Holmes ◽

J.P. Kalejs ◽

...

Keyword(s):

Single Crystal ◽

Fracture Strength ◽

High Power ◽

Single Crystal Silicon ◽

Strength Distribution ◽

Power Laser ◽

Crystal Silicon ◽

Element Analysis ◽

Cut Edge ◽

Basic Hypothesis

AbstractThe fracture twist test is used to obtain the statistical fracture strength distribution for 10-cm square single crystal and polycrystalline silicon wafers cut with a high-power Nd:YAG laser. Tensile wafer edge stresses at fracture are calculated using nonlinear finite element analysis, and the model results are used to examine the limitations of linear torsion and plate theories. The basic hypothesis is that fracture strength of laser-cut wafers is limited by microcracks formed by large residual tensile stresses produced in the cut edge upon cooling after cutting. Differences are found between single crystal CZ and polycrystalline EFG silicon material Weibull parameters characterizing the fracture strength distribution. These indicate that there is a statistical influence of material variables on the fracture strength of the EFG silicon, which lowers its strength and increases the variance of fracture response in comparison to single crystal silicon.

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