The Risk And Solution For No-Clean Flux Not Fully Dried Under Component Terminations the Risk And Solution For No-Clean Flux Not Fully Dried Under Component Terminations
Published: |
November 24, 2020 |
Author: |
Fen Chen and Ning Cheng Lee, Ph.D. |
Abstract: |
The miniaturization trend is driving industry to adopting low standoff components or components in cavity. The cost reduction pressure is pushing telecommunication industry to combine assembly of components and electromagnetic shield in one single reflow process. As a result, the flux outgassing/drying is getting very difficult for devices due to poor venting channel. This resulted in insufficiently dried/burnt-off flux residue. For a properly formulated flux, the remaining flux activity posed no issue in a dried flux residue for no-clean process. However, when venting channel is blocked, not only solvents remain, but also activators could not be burnt off. The presence of solvents allows mobility of active ingredients and the associated corrosion, thus poses a major threat to the reliability. In this work, a new halogen-free no-clean SnAgCu solder paste, 33-76-1, has been developed. This solder paste exhibited SIR value above the IPC spec 100 MΩ without any dendrite formation, even with a wet flux residue on the comb pattern. The wet flux residue was caused by covering the comb pattern with 10 mm × 10 mm glass slide during reflow and SIR testing in order to mimic the poorly vented low standoff components. The paste 33-76-1 also showed very good SMT assembly performance, including voiding of QFN and HIP resistance. The wetting ability of paste 33-76-1 was very good under nitrogen. For air reflow, 33-76-1 still matched paste C which is widely accepted by industry for air reflow process. The above good performance on both non-corrosivity with wet flux residue and robust SMT process can only be accomplished through a breakthrough in flux technology.... |
We apologize but we are unable to find the original text of this article. |
|
You must be a registered user to talk back to us. |
Company Information:
More articles from Indium Corporation »
- Dec 29, 2020 - D-PAK Voiding: A Study to Determine the Origins of D-PAK Voiding
- Jul 24, 2019 - Voiding Performance with Solder Pastes Containing Modified SAC Alloys for Automotive Applications in Bottom Terminated Component Assemblies
- Dec 19, 2018 - Process Optimization for Fine Feature Solder Paste Dispensing
- Nov 20, 2018 - Understanding the Effect of Different Heating Cycles on Post-Soldering Flux Residues and the Impact on Electrical Performance
- Aug 29, 2018 - Does Thermal Cycling Impact the Electrical Reliability of a No-Clean Solder Paste Flux Residue
- See all SMT / PCB technical articles from Indium Corporation »
More SMT / PCB assembly technical articles »
- Apr 11, 2022 - iNEMI Webinar 07.07.2021 - PCB Cleaning | ZESTRON Americas
- Jan 28, 2022 - Open Radio Unit White Box 5G | Whizz Systems
- Nov 10, 2021 - Understanding the Cleaning Process for Automatic Stencil Printers | ITW EAE
- Oct 20, 2021 - PCB Surface Finishes & The Cleaning Process - A Compatibility Study | ZESTRON Americas
- Oct 06, 2021 - Cleaning Before Conformal Coating | ZESTRON Americas
- Browse Technical Library »
The Risk And Solution For No-Clean Flux Not Fully Dried Under Component Terminations the Risk And Solution For No-Clean Flux Not Fully Dried Under Component Terminations article has been viewed 508 times