Technical Articles From Ericsson AB

Head-on-Pillow Defect Detection – X-ray Inspection Limitations

May 26, 2020 | Lars Bruno and Benny Gustafson

Both the number and the variants of Ball Grid Array packages (BGAs) are tending to increase on network Printed Board Assemblies (PBAs)with sizes ranging from a few mm die size Wafer Level Packages (WLPs) with low ball count up to large multi-die System-in-Package (SiP) BGAs with 60-70 mm side lengths and thousands of I/Os....

Key Technology Choices For Optimal Massive IoT Devices

Nov 26, 2019 | Claes Lundqvist, Ari Keranen, Ben Smeets, John Fornehed, Carlos, R.B. Azevedo, Peter Von Wrycza

The latest cellular communication technologies LTE-M and NB-IoT enable the introduction of a new generation of IoT devices that deliver on the promise of scalable, cost-effective massive IoT applications using LPWAN technology. However, a few key technology choices are necessary to create IoT devices that can support the multitude of existing and emerging massive IoT use cases.....

Evaluation of Under-Stencil Cleaning Papers

Aug 04, 2016 | Lars Bruno

Solder paste screen printing is known to be one of the most difficult processes to quality assure in Printed Board Assembly (PBA) manufacturing. An important process step in solder paste screen printing is the under stencil cleaning process and one of the key materials in this process is the cleaning paper1. This, often neglected, material affects the cleaning process and thereby also the print quality. It is therefore important to perform tests of different cleaning papers before one could be chosen.

This article describes how cleaning papers can be tested and it also tells how big differences it can be between different materials....

Printing of Solder Paste - A Quality Assurance Methodology

Oct 01, 2015 | Lars Bruno and Tord Johnson Ericsson AB and MTEK Consulting AB

Solder paste printing is known to be one of the most difficult processes to quality assure in electronic manufacturing. The challenge increases as the technology development moves toward a mix between large modules and small chip components on large and densely populated printed circuit boards. Having a process for quality assurance of the solder paste print is fast becoming a necessity.

This article describes a method to ensure quality secured data from both solder paste printers and inspection machines in electronic assembly manufacturing. This information should be used as feedback in order to improve the solder paste printing process....