Effect of multiple reflows on mechanical strength of the interface formed between Sn–Zn–Bi solder and Au/Ni/Cu bond pad

2007 ◽  
Vol 22 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Ahmed Sharif ◽  
Y.C. Chan ◽  
H.W. Zhong
Keyword(s):  
Shear Test ◽  
Failure Modes ◽  
Ball Grid Array ◽  
Cross Sectional ◽  
X Ray ◽  
Fracture Surfaces ◽  
Reflow Temperature ◽  
Active Nature ◽  
Cross Sectional Studies ◽  
Interfacial Intermetallic Compounds

In this work, the shear strengths and interfacial reactions of Sn–8Zn–3Bi and Sn–8Zn–1Bi (wt%) solders with Au/Ni/Cu ball grid array (BGA) pad metallization were systematically investigated after multiple reflows. The peak reflow temperature was fixed at 230 °C. After the shear test, fracture surfaces were investigated using a scanning electron microscope equipped with an energy dispersive x-ray spectrometer. Cross-sectional studies of the interfaces were also conducted to correlate with the fracture surfaces. Two failure modes, ball cut and pad lift, were assessed for the different solders and reflow cycles. It was found that the shearing forces of both the Sn–Zn–Bi solder joints tended to increase slightly with an increase in the number of reflow cycles due to augmentation of the shearing area. A layer-type spalling of the interfacial intermetallic compounds (IMCs) was observed very early in the liquid-state reaction for the solder alloys. The active nature of the Zn confirmed an instant reaction zone at the interface to maintain the bonding between the solder and the substrate.

Study on the strength of diameter-reducing solder balls by shear and pull tests

2019 ◽  
Vol 31 (4) ◽  
pp. 240-249 ◽  
Author(s):  
Kehang Yu ◽  
Chen Yang ◽  
Jun Wang ◽  
Jiabo Yu ◽  
Yi Yang
Keyword(s):  
Shear Test ◽  
Solder Ball ◽  
Failure Modes ◽  
Element Analysis ◽  
Content Type ◽  
Fracture Surfaces ◽  
Solder Balls ◽  
Pull Tests ◽  
Surface Morphologies ◽  
Force Displacement

Purpose The purpose of this paper is to study the variation of the mechanical strength and failure modes of solder balls with reducing diameters under conditions of multiple reflows. Design/methodology/approach The solder balls with diameters from 250 to 760 µm were mounted on the copper-clad laminate by 1-5 reflows. The strength of the solder balls was tested by the single ball shear test and pull test, respectively. The failure modes of tested samples were identified by combing morphologies of fracture surfaces and force-displacement curves. The stresses were revealed and the failure explanations were assisted by the finite element analysis for the shear test of single solder ball. Findings The average strength of a smaller solder ball (e.g. 250 µm in diameter) is higher than that of a larger one (e.g. 760 µm in diameter). The strength of smaller solder balls is more highly variable with multiple reflows than larger diameters balls, where the strength increased mostly with the number of reflows. According to load-displacement curves or fracture surface morphologies, the failure modes of solder ball in the shear and pull tests can be categorized into three kinds. Originality/value The strength of solder balls will not deteriorate when the diameter of solder ball is decreased with a reflow, but a smaller solder ball has a higher failure risk after multiple reflows. The failure modes for shear and pull tests can be identified quickly by the combination of force-displacement curves and the morphologies of fracture surfaces.

Inspection of ball grid array (BGA) solder joints using x-ray cross-sectional images

1999 ◽  
Author(s):  
Young Jun Roh ◽  
Kuk Won Ko ◽  
Hyungsuck Cho ◽  
Hyung C. Kim ◽  
Hyonam Joo ◽  
...  
Keyword(s):  
Solder Joints ◽  
Ball Grid Array ◽  
Cross Sectional ◽  
X Ray

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

A STUDY ON THE CORRELATION BETWEEN MORPHOLOGIC ANORMALIES AND LEFT VENTRICULAR DIASTOLIC FUNCTION IN DILATED CARDIO-MYOPATHY

2011 ◽  
pp. 137-144
Author(s):  
Thi Ngoc Ha Hoang ◽  
Anh Vu Nguyen ◽  
Minh Loi Hoang ◽  
Cuu Long Nguyen ◽  
Thi Thuy Hang Nguyen
Keyword(s):  
Pulmonary Artery ◽  
Dilated Cardiomyopathy ◽  
Diastolic Dysfunction ◽  
Diastolic Function ◽  
Pulmonary Arteries ◽  
Left Ventricular ◽  
University Hospital ◽  
Cross Sectional ◽  
X Ray ◽  
Key Words Dilated Cardiomyopathy

Purposes: Describe the morphological and diastolic function of left ventricular changes in the patients with dilated cardiomyopathy (DCM) on US, X-ray findings, and Evaluate the correlation between morphology and diastolic function of left ventricular. Materials and method: Cross sectional study from Dec 2009 to Aug 2010, on 39 patients with dilated cardiomyopathy were evaluated at the University Hospital of Hue College of Medical and Pharmaceutical. Results: 1. X-ray and US findings characteristics of DCM is significantly increased in diameter of L, H and mG; LVM, LVMI, LVDd and LAD. 2. The pression of pulmonary artery has been significantly increased with redistribution pulmonary arteries in 61.5% cases and 23.1% have reversed pulmonary artery distribution. 3. DCM have diastolic dysfunction in 100% patients, including severe disorders to 61.5%; the restrictive dysfunction has ratio E/A>2 and E/Em average was 23.89± 17.23. 4.The correlation between the morphology and function in DCM: the diameter of H and L on the X-ray, LAD and ratio LA/AO on US correlated with the level of diastolic dysfunction (p< 0.05). All three radiographic parameters on the radio standard (H, L, the index Cardio/Thoracic) and LVDd on US have negative correlated with EF and FS with p <0.05. Key words: dilated cardiomyopathy, diastolic dysfunction, cardiac tissue Doppler, reversed pulmonary artery distribution

OSTEOPOROSIS AND RISK FACTORS IN THE PATIENTS ON CHRONIC HEMODIALYSIS

2015 ◽  
pp. 50-58
Author(s):  
Thi Dung Nguyen ◽  
Tam Vo
Keyword(s):  
Quality Of Life ◽  
Risk Factors ◽  
Bone Density ◽  
Region Of Interest ◽  
Cross Sectional Study ◽  
Chronic Hemodialysis ◽  
Cross Sectional ◽  
X Ray ◽  
Density Reduction

Background: The patients on hemodialysis have a significantly decreased quality of life. One of many problems which reduce the quality of life and increase the mortality in these patients is osteoporosis and osteoporosis associated fractures. Objectives: To assess the bone density of those on hemodialysis by dual energy X ray absorptiometry and to examine the risk factors of bone density reduction in these patients. Patients and Method: This is a cross-sectional study, including 93 patients on chronic hemodialysis at the department of Hemodialysis at Cho Ray Hospital. Results: Mean bone densities at the region of interest (ROI) neck, trochanter, Ward triangle, intertrochanter and total neck are 0.603 ± 0.105; 0.583 ± 0.121; 0.811 ± 0.166; 0.489 ± 0.146; 0.723 ± 0.138 g/cm2 respectively. The prevalences of osteoporosis at those ROI are 39.8%, 15.1%; 28%; 38.7%; and 26.9% respectively. The prevalences of osteopenia at those ROI are 54.8%; 46.3%; 60.2%; 45.2% and 62.7% respectively. The prevalence of osteopososis in at least one ROI is 52.7% and the prevalence of osteopenia in at least one ROI is 47.3%. There are relations between the bone density at the neck and the gender of the patient and the albuminemia. Bone density at the trochanter is influenced by gender, albuminemia, calcemia and phosphoremia. Bone density at the intertrochanter is affected by the gender. Bone density at the Ward triangle is influenced by age and albuminemia. Total neck bone density is influenced by gender, albuminemia and phosphoremia. Conclusion: Osteoporosis in patients on chronic hemodialysis is an issue that requires our attention. There are many interventionable risk factors of bone density decrease in these patients. Key words: Osteoporosis, DEXA, chronic renal failure, chronic hemodialysis

Blood Parathyrin and Mineral Metabolism Dynamics. A clinical analyze

2018 ◽  
Vol 69 (10) ◽  
pp. 2754-2758
Author(s):  
Lucretiu Radu ◽  
Mara Carsote ◽  
Ancuta Augustina Gheorghisan Galateanu ◽  
Smaranda Adelina Preda ◽  
Veronica Calborean ◽  
...  
Keyword(s):  
Case Control Study ◽  
Mineral Metabolism ◽  
Lumbar Bone Mineral Density ◽  
Urinary Calcium ◽  
Mineral Density ◽  
Cross Sectional ◽  
X Ray ◽  
Menopausal Women ◽  
Ionic Calcium ◽  
Control Study

Circulating parathyrin (PTH or parthormon) is increased in primary hyperparathyroidism (PHP) in association with high total/ionic calcium (T/I Ca) and others mineral metabolism anomalies. This is a clinical cross-sectional and case-control study analyzing these changes after PHP surgical correction in menopausal women. Baseline parameters were: mean age at diagnosis (59.63�9.6 years), TCa of 10.9�0.7 mg/dL, PTH of 138.02�59.36 pg/mL. Longitudinal data showed: final TCa p[0.00001, ICa p[0.00001, phosphorus p[0.0001, magnesium p=0.9, 24-h urinary calcium p=0.4, 25-hydroxycholecalciferol p=0.01, PTH p[0.00001. High circulating parathyrin values due to PHP normalized after surgery in addition to statistical significant changes of TCa, ICa, P, lumbar Bone Mineral Density provided by Dual-Energy X-Ray Absorptiometry; Mg and 24-h Ca might not be a marker of general mineral metabolism improvement.

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