Misaligned Flip-Chip Solder Joints: Prediction and Experimental Determination of Force-Displacement Curves

2002 ◽  
Vol 124 (3) ◽  
pp. 227-233 ◽  
Author(s):  
D. Josell ◽  
W. E. Wallace ◽  
J. A. Warren ◽  
D. Wheeler ◽  
A. C. Powell
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
Minimum Energy ◽  
Computer Code ◽  
Silicon Substrates ◽  
Surface Evolver ◽  
Solder Volume ◽  
Lateral Offset ◽  
Force Displacement

The results of wetting experiments between eutectic lead-tin solder and copper pads on silicon substrates in geometries relevant to flip-chip applications are presented. Measurements of solder joint dimensions, specifically stand-off height and lateral offset (i.e., misalignment), as functions of the applied force (normal and shear), solder volume and pad diameter are presented. The experimentally-measured force-displacement relationships are compared with predictions obtained from the minimum energy model of the Surface Evolver computer code. For the case of the axisymmetric joint (zero shear) an exact solution to the capillary equations is also presented. The comparison of experimental and modeling results indicates that such models are accurate as well as extremely sensitive means for predicting the geometry of these solder joints.

Crack Propagation Experiments on Flip Chip Solder Joints

1998 ◽  
Vol 515 ◽  
Author(s):  
S. Wiese ◽  
F. Feustel ◽  
S. Rzepka ◽  
E. Meusel
Keyword(s):  
Crack Propagation ◽  
Flip Chip ◽  
Solder Joints ◽  
Shear Loading ◽  
Displacement Curve ◽  
In Situ Experiments ◽  
Propagation Experiment ◽  
Crack Propagation Experiment ◽  
Number Of Cycles ◽  
Force Displacement

ABSTRACTThe paper presents crack propagation experiments on real flip chip specimens applied to reversible shear loading. Two specially designed micro testers will be introduced. The first tester provides very precise measurements of the force displacement hysteresis. The achieved resolutions have been I mN for force and 20 nm for displacement. The second micro tester works similar to the first one, but is designed for in-situ experiments inside the SEM. Since it needs to be very small in size it reaches only resolutions of 10 mN and 100nm, which is sufficient to achieve equivalence to the first tester. A cyclic triangular strain wave is used as load profile for the crack propagation experiment. The experiment was done with both machines applying equivalent specimens and load. The force displacement curve was recorded using the first micro mechanical tester. From those hysteresis, the force amplitude has been determined for every cycle. All force amplitudes are plotted versus the number of cycles in order to quantify the crack length. With the second tester, images were taken at every 10th … 100th cycle in order to locate the crack propagation. Finally both results have been linked together for a combined quatitive and spatial description of the crack propagation in flip chip solder joints.

scholarly journals Design of Solder Connections for Self-Assembly of Optoelectronic Devices

2019 ◽  
Vol 16 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Thomas F. Marinis ◽  
Joseph W. Soucy
Keyword(s):  
Surface Tension ◽  
Flip Chip ◽  
Equilibrium Shape ◽  
High Surface ◽  
Optoelectronic Devices ◽  
Analytical Models ◽  
Volume Control ◽  
Surface Evolver ◽  
Solder Volume ◽  
Connected Set

Abstract In surface mount assembly, advantage is taken of the high surface tension of molten solder to self-align ball grid array packages and flip chip die. However, in these applications, the volume of solder applied as paste by stencil printing is not sufficiently well controlled to achieve the precise alignment required for optoelectronic devices. We believe that the requirement on solder volume control for assembly of optoelectronic devices can be relaxed by designing the bond pads so that the height or alignment of connections is controlled by the surface tension of the solder rather than its volume. Our design approach to accomplishing this is to connect auxiliary pads to the primary attachment pad, which act as solder reservoirs. Surface tension causes the solder to be redistributed among these pads to achieve a uniform pressure throughout the solder volume. This phenomena is governed by the Young-Laplace equation, ΔP = γκ, in which ΔP represents the difference in pressure within and outside the solder, γ the surface tension of the solder, and κ the local curvature of the solder surface. Thus, the design of the set of primary and auxiliary pads is critically important to realizing the desired control of joint height. In this article, we describe the use of the Surface Evolver software package in combination with analytical models, to analyze the behavior of various connection configurations with respect to variations in printed solder volume. Specifically, we calculate the equilibrium shape of the solder surface over the connected set of pads and examine how control of joint height is affected by the number, size, and geometry of auxiliary pad configurations.

Predicting the Liquid Formation for the Solder Joints in Flip Chip Technology

2005 ◽  
Vol 128 (4) ◽  
pp. 331-338 ◽  
Author(s):  
Wen-Hwa Chen ◽  
Shu-Ru Lin ◽  
Kuo-Ning Chiang
Keyword(s):  
Surface Tension ◽  
Solder Joint ◽  
Flip Chip ◽  
Solder Joints ◽  
Geometric Method ◽  
External Loading ◽  
Surface Evolver ◽  
Eutectic Solder ◽  
Chip Technology ◽  
Interfacial Surface

An accurate and efficient analytical geometric method is presented for predicting the geometric parameters of the controlled collapse chip connection type solder joint using direct chip attach technology after a reflow process. By this method, the meridian of the solder joint is first discretized as a series of sufficiently fine fragmental arcs. After calculating the internal pressure inside the molten eutectic solder from the forces balance, the meridional and circumferential radii of curvature of each arc are then obtained from the Laplace-Young equation. As a result, the coordinates of each node of the arc and the solder joint geometry can be determined in turn. The factors that affect the final shape of the molten eutectic solder joints, including the solder volumes, external loading, pad size, surface tension of molten eutectic solder, and interfacial surface tension between the molten eutectic solder and the solid high-lead bump are considered herein. The results computed by the analytical geometric method are also compared with those obtained using the Surface Evolver program, the extended Heinrich’s model, and the experimental results. The results of the various approaches are mutually consistent.

Reliability of Fine Pitch Sn–3.8Ag–0.7Cu Flip Chip Solder Joints With Different Connection Pads on PCB

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Dezhi Li ◽  
Changqing Liu ◽  
Paul P. Conway
Keyword(s):  
Flip Chip ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Bulk Solder ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Fine Pitch ◽  
Solder Volume ◽  
Failure Location ◽  
Solder Interface

The reliability of fine pitch Sn–3.8Ag–0.7Cu flip chip solder joints with three different pads, i.e., bare pads, pads with solder masks, and pads with microvia, on printed circuit boards (PCBs) was studied through thermal cycling. After assembly, (Au,Ni)Sn4 intermetallics (IMCs) formed both in the bulk solder and at the interfaces due to the immersion-Au finish on the PCB side. The (Au,Ni)Sn4 IMCs formed in the solder joints on the pads with microvia were more abundant than those formed in the solder joints on the pads without microvia. The results showed that the solder joints on the pads with a microvia had poor reliability due to the insufficient solder volume and the formation of large amounts of (Au,Ni)Sn4 IMCs. The main crack initiation position was the corner of solder joint at the chip side. For the pads with microvia, the main location of failure was at the (Au,Ni)Sn4/solder interface on the chip side, and for the solder joints on bare pads and pads with solder mask, the possible failure location was in the bulk solder.

Determination of Sub‐Parts per Billion Boron Contamination in N+ Czochralski Silicon Substrates by SIMS

1994 ◽  
Vol 141 (12) ◽  
pp. 3453-3456 ◽  
Author(s):  
Paul K. Chu ◽  
Roger J. Bleiler ◽  
Jenny M. Metz
Keyword(s):  
Silicon Substrates ◽  
Czochralski Silicon

Rapid diagnosis of electromigration induced failure time of Pb-free flip chip solder joints by high resolution synchrotron radiation laminography

2011 ◽  
Vol 99 (8) ◽  
pp. 082114 ◽  
Author(s):  
Tian Tian ◽  
Feng Xu ◽  
Jung Kyu Han ◽  
Daechul Choi ◽  
Yin Cheng ◽  
...  
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
Flip Chip ◽  
Solder Joints ◽  
Failure Time ◽  
Rapid Diagnosis

Effect of entropy production on microstructure change in eutectic SnPb flip chip solder joints by thermomigration

2006 ◽  
Vol 89 (22) ◽  
pp. 221906 ◽  
Author(s):  
Fan-Yi Ouyang ◽  
K. N. Tu ◽  
Yi-Shao Lai ◽  
Andriy M. Gusak
Keyword(s):  
Entropy Production ◽  
Flip Chip ◽  
Solder Joints ◽  
Microstructure Change ◽  
Eutectic Snpb
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