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Solder Paste Fitness Monitoring

Presenter: Denis Barbini, Ph.D.
Company: Insituware
Date Published: 5/21/2020

Description: Organized by the SMTA Dallas Chapter

The miniaturization of components has caused increased the defects in the Surface Mount Technology (SMT) process during the solder paste printing. The root cause of solder paste printing failures is often attributed to the stencil, squeegee, or printing process parameters; however, the solder paste is often overlooked and could be the cause of printing and soldering defects. Although there are current methods for quality control of solder pastes such as rheological techniques, they are not commonly used because of their complexity and high costs. Therefore, there is a need to implement a more affordable and efficient tool to control the solder paste before and during its use in order to reduce printing failures and minimize variations in the SMT process. In this research, electrochemical impedance spectroscopy was used as a method of inspecting solder paste to determine if paste printability, or its fitness for use, could be predicted. The solder paste was worked over an extended period of time while samples were extracted for rheological and electrochemical measurements. In another case, the solder paste was subjected to high temperatures in order to simulate an accelerated aging process as if the jar was experiencing poor shipment/handling conditions. Based on the results, there is an increase in the time constants of the flux-powder interface that directly correlates to the decrease in recoverability of the paste over time. Overall, a solder paste’s fitness for use can be predicted through the correlation of electrochemical and rheological measurements.

About the Presenter:

Dr. Denis Barbini is an experienced General Director with a demonstrated history of working in the electrical and electronic manufacturing industry. He is skilled in DMAIC, Value Stream Mapping, Failure Mode and Effects Analysis (FMEA), Quality Management, and Root Cause Analysis, and a strong sales professional with a Ph.D. focused in Chemistry, Material Science from State University of New York at Binghamton.

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