Quantitative Solder Wetting Measurement for DCA Assembly

1992 ◽  
Vol 114 (4) ◽  
pp. 476-479 ◽  
Author(s):  
Cynthia M. Melton ◽  
Carl J. Raleigh ◽  
Susan M. Yarling
Keyword(s):  
Contact Angle ◽  
Measurement Technique ◽  
Continuous Monitoring ◽  
Solder Ball ◽  
Nitrogen Atmosphere ◽  
Base Diameter ◽  
Solder Flux ◽  
Wettability Measurement ◽  
Full Factorial ◽  
Final Degree

A quantitative dynamic solder wettability measurement technique was utilized to evaluate the effects of reflow processing on the wettability parameters associated with solder ball alloys. This technique enables the examination of the final degree of solder wetting and the continuous monitoring of wetting as a function of time during the reflow process under nitrogen atmosphere. An experimental design approach employing a 24 full factorial experiment was formulated to illustrate the use of this measurement technique investigating the final result of wetting. Solder wettability was determined with respect to the contact angle, base diameter and height of the reflowed solder ball alloy. The most significant effect estimates with respect to contact angle were solder flux and pad metallization. Solder ball alloy was found to significantly impact the base diameter and height of the reflowed solder. The effect of solder flux activators and pad metallizations on the subsequent continuous solder wettability wetting rates and amount of molten solder spread of solder ball alloys during reflow were measured. Reflow with a relatively more activated solder flux material was found to enhance the rate of solder wetting of the pad metallization.

Continuous Wetiability Measurement for Solder Reflow

1991 ◽  
Vol 226 ◽  
Author(s):  
Cynthia M. Melton ◽  
Susan M. Yarling ◽  
Carl J. Raleigh
Keyword(s):  
Contact Angle ◽  
Continuous Monitoring ◽  
Solder Ball ◽  
Nitrogen Atmosphere ◽  
Molten Solder ◽  
Reflow Process ◽  
Base Diameter ◽  
Solder Flux ◽  
Full Factorial ◽  
Final Degree

AbstractA quantitative dynamic solder wettability mesurement technique was utilized to evaluate the effects of reflow processing on the wettability parameters associated with solder ball alloys. This technique enables the examination of the final degree of solder wetting and the continuous monitoring of wetting as a function of time during the reflow process under nitrogen atmosphere. An experimental design approach employing a 24 full factorial experiment was formulated to illustrate the use of this measurement technique investigating the final result of wetting. Solder wettability was determined with respect to the contact angle, base diameter and height of the reflowed solder ball alloy. The most significant effect estimates with respect to contact angle were solder flux and pad metallization. Solder ball alloy was found to significantly impact the base diameter and height of the reflowed solder. The effect of solder flux activators and pad metallizations on the subsequent continuous solder wettability wetting rates and amount of molten solder spread of solder ball alloys during reflow were measured. Reflow with a relatively more activated solder flux material was found to enhance the rate of solder wetting of the the pad metallization.

scholarly journals 305 PRESSURE OF SAP EXUDATE OF TOMATO PLANTS IN VARIED ROOT ENVIRONMENTS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 474a-474
Author(s):  
Fude Yao ◽  
Kenneth Corey
Keyword(s):  
Pressure Transducer ◽  
Continuous Monitoring ◽  
Root Zone ◽  
Data Acquisition System ◽  
Nitrogen Atmosphere ◽  
Time Data ◽  
Tomato Plants ◽  
Real Time Data ◽  
Hydroponically Grown ◽  
Over Time

Sap pressure of cut tomato stems was monitored using a real time data acquisition system to assess changes in the root zone environment. Hydroponically-grown tomato plants were cut and a gas-free connection made to a temperature-compensated pressure transducer. When plants were bathed in nutrient solution under isothermal conditions, pressure increased to a maximum within 10 to 75 min; maxima varied in the range of 20 kPa to 150 kPa. A fatigue phenomenon occurred with all plants, exhibited by decreases in pressure maxima over time. When root zone aeration was stopped or a nitrogen atmosphere was used, pressure dropped following a lag of about 30 min. This decrease in pressure was partially reversible when aeration was resupplied. Near instantaneous changes in sap pressure occurred when the root zone was manipulated by imposing a temperature gradient or by increasing the osmolarity of the solution. The technique reported may be useful for continuous monitoring of changes in the root zone environment and in assessing plant health.

scholarly journals Wetting and Spreading of Commercially Available Aqueous Surfactants on Porous Materials

2019 ◽  
Vol 3 (1) ◽  
pp. 14 ◽  
Author(s):  
Phillip Johnson ◽  
Toby Routledge ◽  
Anna Trybala ◽  
Mauro Vaccaro ◽  
Victor Starov
Keyword(s):  
Contact Angle ◽  
Porous Media ◽  
Surfactant Concentration ◽  
Degree Of Saturation ◽  
Distilled Water ◽  
Base Diameter ◽  
Complete Wetting ◽  
Wetting Properties ◽  
Surfactant Solutions ◽  
Aqueous Surfactants

The wetting properties of aqueous solutions of a commercially available surfactant at various concentrations on porous media are investigated using the KRUSS DSA100 shape analyzer and the ADVANCED software to process the data. Time evolution of both the contact angle and drop base diameter at each surfactant concentration after deposition were monitored. Three different porous substrates (sponges) were examined. The sponges used were a car sponge, dish sponge and audio sponge. The sponges were investigated both dry and at different degrees of saturation, that is, the amount of water absorbed into the sponge. It was found that pure distilled water droplets deposited on the dry porous media showed non-wetting. However, if droplets of surfactant solutions were deposited, then a change to a complete wetting case was found at all surfactant concentrations used. It has been observed that for all sponges, no matter the degree of saturation, they display a minimum contact angle after which the droplet is rapidly absorbed into the porous media.

Wettability and Surface Roughness Study on RIE Treated Aluminium Deposited Surface

2014 ◽  
Vol 925 ◽  
pp. 101-104
Author(s):  
Vithyacharan Retnasamy ◽  
Zaliman Sauli ◽  
Uda Hashim ◽  
Moganraj Palianysamy ◽  
Aaron Koay Terr Yeow ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Factorial Design ◽  
Process Parameters ◽  
Design Of Experiment ◽  
Etch Rate ◽  
Contact Angles ◽  
Atomic Force ◽  
Roughness Analysis ◽  
Full Factorial

Design of Experiment (DOE) is a technique for optimizing process which has controllable inputs and measurable outputs. As a method of DOE, 24 Full Factorial design is used to study the effect of Reactive Ion Etch towards the surface roughness of aluminum pad and effect of the roughness produced towards the contact angle. Surface roughness analysis is done using Atomic Force Microscop (AFM). Contact angle is measured using AutoCad software from the images captured from droplet test. This contact angles must be more than 90° for non-wetting profile or less than 90° for wetting profile. This work is also done to understand the interaction between the process parameters and how each parameters will affect the etch rate. The results are analyzed which shows that the increase in surface roughness produces an increase on the contact angle and vice versa.

scholarly journals Data-driven time-dependent state estimation for interfacial fluid mechanics in evaporating droplets

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahar Andalib ◽  
Kunihiko Taira ◽  
H. Pirouz Kavehpour
Keyword(s):  
Contact Angle ◽  
Time Evolution ◽  
Droplet Evaporation ◽  
Data Driven ◽  
Sessile Droplet ◽  
Base Diameter ◽  
Point Analysis ◽  
Regression Techniques ◽  
New Perspective ◽  
Substrate Temperatures

AbstractDroplet evaporation plays crucial roles in biodiagnostics, microfabrication, and inkjet printing. Experimentally studying the evolution of a sessile droplet consisting of two or more components needs sophisticated equipment to control the vast parameter space affecting the physical process. On the other hand, the non-axisymmetric nature of the problem, attributed to compositional perturbations, introduces challenges to numerical methods. In this work, droplet evaporation problem is studied from a new perspective. We analyze a sessile methanol droplet evolution through data-driven classification and regression techniques. The models are trained using experimental data of methanol droplet evolution under various environmental humidity levels and substrate temperatures. At higher humidity levels, the interfacial tension and subsequently contact angle increase due to higher water uptake into droplet. Therefore, different regimes of evolution are observed due to adsorption–absorption and possible condensation of water which turns the droplet from a single component into a binary system. In this work, machine learning and data-driven techniques are utilized to estimate the regime of droplet evaporation, the time evolution of droplet base diameter and contact angle, and level of surrounding humidity. Droplet regime is estimated by classification algorithms through point-by-point analysis of droplet profile. Decision tree demonstrates a better performance compared to Naïve Bayes (NB) classifier. Additionally, the level of surrounding humidity, as well as the time evolution of droplet base diameter and contact angle, are estimated by regression algorithms. The estimation results show promising performance for four cases of methanol droplet evolution under conditions unseen by the model, demonstrating the model’s capability to capture the complex physics underlying binary droplet evolution.

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